U.S. patent application number 16/548445 was filed with the patent office on 2019-12-05 for isolation, detection, diagnosis and/or characterization of circulating trop-2-positive cancer cells.
The applicant listed for this patent is Immunomedics, Inc.. Invention is credited to Chien-Hsing Chang, David M. Goldenberg, Hans J. Hansen.
Application Number | 20190369103 16/548445 |
Document ID | / |
Family ID | 57144272 |
Filed Date | 2019-12-05 |
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United States Patent
Application |
20190369103 |
Kind Code |
A1 |
Goldenberg; David M. ; et
al. |
December 5, 2019 |
ISOLATION, DETECTION, DIAGNOSIS AND/OR CHARACTERIZATION OF
CIRCULATING TROP-2-POSITIVE CANCER CELLS
Abstract
Described herein are compositions and methods of use of
anti-Trop-2 antibodies or antigen-binding fragment thereof to
isolate, enrich, detect, diagnose and/or characterize circulating
tumor cells (CTCs) from patients with a Trop-2 positive cancer.
Preferably, the antibody is an RS7, 162-46.2 or MAB650 antibody.
The compositions and methods are of use to detect, diagnose and/or
treat metastatic Trop-2.sup.+ cancers, such as breast, ovarian,
cervical, endometrial, lung, prostate, colon, rectum, stomach,
esophageal, bladder, renal, pancreatic, thyroid, epithelial or
head-and-neck cancer.
Inventors: |
Goldenberg; David M.;
(Delray Beach, FL) ; Hansen; Hans J.; (Picayune,
MS) ; Chang; Chien-Hsing; (Downingtown, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Immunomedics, Inc. |
Morris Plains |
NJ |
US |
|
|
Family ID: |
57144272 |
Appl. No.: |
16/548445 |
Filed: |
August 22, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15707404 |
Sep 18, 2017 |
10436788 |
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16548445 |
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15135758 |
Apr 22, 2016 |
9797907 |
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15707404 |
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62151169 |
Apr 22, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61P 35/04 20180101;
A61K 47/6803 20170801; G01N 33/574 20130101; A61P 35/00 20180101;
A61K 47/6857 20170801; G01N 33/57492 20130101; G01N 2001/4038
20130101; A61K 31/4745 20130101; G01N 1/405 20130101; G01N 33/57488
20130101; A61K 47/6855 20170801; G01N 2333/705 20130101; A61K
47/6863 20170801; A61K 47/6859 20170801 |
International
Class: |
G01N 33/574 20060101
G01N033/574; G01N 1/40 20060101 G01N001/40; A61K 31/4745 20060101
A61K031/4745; A61K 47/68 20060101 A61K047/68 |
Claims
1. A method of diagnosing Trop-2.sup.+ tumors comprising: a)
exposing an anti-Trop-2 antibody or antigen-binding fragment
thereof to blood, serum or plasma from a subject suspected of
having a Trop-2.sup.+ cancer, wherein the anti-Trop-2 antibody or
fragment thereof is the sole anti-TAA (tumor associated antigen)
capture antibody; b) allowing the anti-Trop-2 antibody or fragment
thereof to bind to Trop-2.sup.+ circulating tumor cells (CTCs); c)
collecting Trop-2+ CTCs bound to the anti-Trop-2 antibody or
fragment thereof; and d) analyzing the Trop-2+ CTCs for the
presence of one or more cancer biomarkers.
2. The method of claim 1, wherein the cancer biomarker is the copy
number of Trop-2 genes per cell, wherein the presence of a copy
number of Trop-2 of 3 or more per cell is predictive of response to
a therapeutic anti-Trop-2 antibody or immunoconjugate.
3. The method of claim 2, wherein the immunoconjugate is an
anti-Trop-2 antibody-drug conjugate (ADC).
4. The method of claim 3, wherein the anti-Trop-2 ADC is
sacituzumab govitecan.
5. The method of claim 1, further comprising administering to the
subject an anti-Trop-2 ADC.
6. The method of claim 5, further comprising administering to the
subject a therapeutic agent selected from the group consisting of
an antibody, an antibody fragment, an antibody-drug conjugate, a
drug, a toxin, a hormone, an immunomodulator, a pro-apoptotic
agent, an anti-angiogenic agent, and a photoactive agent.
7. The method of claim 6, wherein the drug is selected from the
group consisting of an anthracycline, a camptothecin, a tubulin
inhibitor, a maytansinoid, a calicheamycin, an auristatin, a
nitrogen mustard, an ethylenimine derivative, an alkyl sulfonate, a
nitrosourea, a triazene, a folic acid analog, a taxane, a COX-2
inhibitor, a pyrimidine analog, a purine analog, an antibiotic, an
enzyme inhibitor, an epipodophyllotoxin, a platinum coordination
complex, a vinca alkaloid, a substituted urea, a methyl hydrazine
derivative, an adrenocortical suppressant, a hormone antagonist, an
antimetabolite, an alkylating agent, an antimitotic, an
anti-angiogenic agent, a tyrosine kinase inhibitor, an mTOR
inhibitor, a heat shock protein (HSP90) inhibitor, a proteosome
inhibitor, an HDAC inhibitor, and a pro-apoptotic agent.
8. The method of claim 6, wherein the drug is selected from the
group consisting of 5-fluorouracil, afatinib, aplidin, azaribine,
anastrozole, anthracyclines, axitinib, AVL-101, AVL-291,
bendamustine, bleomycin, bortezomib, bosutinib, bryostatin-1,
busulfan, calicheamycin, camptothecin, carboplatin,
10-hydroxycamptothecin, carmustine, celecoxib, chlorambucil,
cisplatinum, COX-2 inhibitors, irinotecan (CPT-11), SN-38,
carboplatin, cladribine, camptothecans, crizotinib,
cyclophosphamide, cytarabine, dacarbazine, dasatinib, dinaciclib,
docetaxel, dactinomycin, daunorubicin, DM1, DM3, DM4, doxorubicin,
2-pyrrolinodoxorubicine (2-PDox), cyano-morpholino doxorubicin,
doxorubicin glucuronide, endostatin, epirubicin glucuronide,
erlotinib, estramustine, epidophyllotoxin, erlotinib, entinostat,
estrogen receptor binding agents, etoposide (VP16), etoposide
glucuronide, etoposide phosphate, exemestane, fingolimod,
floxuridine (FUdR), 3',5'-O-dioleoyl-FudR (FUdR-dO), fludarabine,
flutamide, farnesyl-protein transferase inhibitors, flavopiridol,
fostamatinib, ganetespib, GDC-0834, GS-1101, gefitinib,
gemcitabine, hydroxyurea, ibrutinib, idarubicin, idelalisib,
ifosfamide, imatinib, lapatinib, lenolidamide, leucovorin, LFM-A13,
lomustine, mechlorethamine, melphalan, mercaptopurine,
6-mercaptopurine, methotrexate, mitoxantrone, mithramycin,
mitomycin, mitotane, monomethylauristatin F (MMAF),
monomethylauristatin D (MMAD), monomethylauristatin E (MMAE),
navelbine, neratinib, nilotinib, nitrosurea, olaparib, plicomycin,
procarbazine, paclitaxel, PCI-32765, pentostatin, PSI-341,
raloxifene, semustine, SN-38, sorafenib, streptozocin, SU11248,
sunitinib, tamoxifen, temazolomide, transplatinum, thalidomide,
thioguanine, thiotepa, teniposide, topotecan, uracil mustard,
vatalanib, vinorelbine, vinblastine, vincristine, vinca alkaloids
and ZD1839.
9. The method of claim 6, wherein the toxin is selected from the
group consisting of ricin, abrin, alpha toxin, saporin,
ribonuclease (RNase), DNase I, Staphylococcal enterotoxin-A,
pokeweed antiviral protein, gelonin, diphtheria toxin, Pseudomonas
exotoxin, and Pseudomonas endotoxin.
10. The method of claim 6, wherein the immunomodulator is selected
from the group consisting of a cytokine, a stem cell growth factor,
a lymphotoxin, a hematopoietic factor, a colony stimulating factor
(CSF), an interferon (IFN), an interleukin, erythropoietin and
thrombopoietin.
11. The method of claim 10, wherein the cytokine is selected from
the group consisting of human growth hormone, N-methionyl human
growth hormone, bovine growth hormone, parathyroid hormone,
thyroxine, insulin, proinsulin, relaxin, prorelaxin, follicle
stimulating hormone (FSH), thyroid stimulating hormone (TSH),
luteinizing hormone (LH), hepatic growth factor, prostaglandin,
fibroblast growth factor, prolactin, placental lactogen, OB
protein, tumor necrosis factor-.alpha., tumor necrosis
factor-.beta., mullerian-inhibiting substance, mouse
gonadotropin-associated peptide, inhibin, activin, vascular
endothelial growth factor, integrin, thrombopoietin (TPO),
NGF-.beta., platelet-growth factor, TGF-.alpha., TGF-.beta.,
insulin-like growth factor-I, insulin-like growth factor-II,
erythropoietin (EPO), osteoinductive factors, interferon-.alpha.,
interferon-.beta., interferon-.gamma., macrophage-CSF (M-CSF),
IL-1, IL-1.alpha., IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9,
IL-10, IL-11, IL-12, IL-13, IL-14, IL-15, IL-16, IL-17, IL-18,
IL-21, IL-25, LIF, FLT-3, angiostatin, thrombospondin, endostatin,
tumor necrosis factor and lymphotoxin.
12. The method of claim 6, wherein the antibody is a checkpoint
inhibitor antibody.
13. The method of claim 12, wherein the checkpoint inhibitor
antibody is an anti-CTLA4, anti-PD-1 or anti-PD-L1 antibody.
14. The method of claim 12, wherein the checkpoint inhibitor
antibody is selected from the group consisting of pembrolizumab,
nivolumab, pidilizumab, ipilimumab, tremelimumab, AMP-224,
MDX-1105, MEDI4736, MPDL3280A, and BMS-936559.
15. The method of claim 1, wherein the Trop-2.sup.+ cancer is
selected from the group consisting of pancreatic cancer,
triple-negative breast cancer, colorectal cancer, breast cancer,
non-small-cell lung cancer (NSCLC), pancreatic cancer, esophageal
cancer, urothelial cancer, renal cell carcinoma, gastric cancer,
prostate cancer, and small-cell lung cancer.
16. The method of claim 15, wherein the cancer is metastatic.
17. The method of claim 1, wherein the cancer biomarker comprises a
mutation or change in copy number in a gene encoding a
tumor-associated antigen (TAA).
18. The method of claim 17, wherein the TAA is selected from the
group consisting of carbonic anhydrase IX, B7, CCL19, CCL21, CSAp,
HER-2/neu, BrE3, CD1, CD1a, CD2, CD3, CD4, CD5, CD8, CD11A, CD14,
CD15, CD16, CD18, CD19, CD20, CD21, CD22, CD23, CD25, CD29, CD30,
CD32b, CD33, CD37, CD38, CD40, CD40L, CD44, CD45, CD46, CD47, CD52,
CD54, CD55, CD59, CD64, CD67, CD70, CD74, CD79a, CD80, CD83, CD95,
CD126, CD133, CD138, CD147, CD154, CEACAM5, CEACAM6, CTLA-4,
alpha-fetoprotein (AFP), VEGF, ED-B fibronectin, EGP-1 (Trop-2),
EGP-2, EGF receptor, ErbB2, ErbB3, Factor H, Flt-1, Flt-3, folate
receptor, Ga 733,GRO-.beta., HMGB-1, hypoxia inducible factor,
HM1.24, HER-2/neu, histone H2B, histone H3, histone H4,
insulin-like growth factor, IFN-.gamma., IFN-.alpha., IFN-.beta.,
IFN-.lamda., IL-2R, IL-4R, IL-6R, IL-13R, IL-15R, IL-17R, IL-18R,
IL-2, IL-6, IL-8, IL-12, IL-15, IL-17, IL-18, IL-25, IP-10, IGF-1R,
Ia, HM1.24, gangliosides, HCG, HLA-DR, CD66a-d, MAGE, mCRP, MCP-1,
MIP-1A, MIP-1B, macrophage migration-inhibitory factor (MIF), MUC1,
MUC2, MUC3, MUC4, MUC5ac, placental growth factor, PSA
(prostate-specific antigen), PSMA, PD-1 receptor, PD-L1, NCA-95,
NCA-90, A3, A33, Ep-CAM, KS-1, Le(y), mesothelin, S100, tenascin,
TAC, Tn antigen, Thomas-Friedenreich antigens, tumor necrosis
antigens, tumor angiogenesis antigens, TNF-.alpha., TRAIL receptor
R1, TRAIL receptor R2, VEGFR, RANTES, T101, complement factors C3,
C3a, C3b, C5a, C5, and an oncogene product.
19. The method of claim 5, further comprising monitoring the
presence to Trop-2.sup.+ CTCs in the circulation to determine the
response of the tumor to the therapeutic anti-Trop-2 ADC.
20. The method of claim 1, wherein the anti-Trop-2 antibody is an
RS7 antibody comprising light chain CDR sequences CDR1
(KASQDVSIAVA, SEQ ID NO:1); CDR2 (SASYRYT, SEQ ID NO:2); and CDR3
(QQHYITPLT, SEQ ID NO:3) and the heavy chain CDR sequences CDR1
(NYGMN, SEQ ID NO:4); CDR2 (WINTYTGEPTYTDDFKG, SEQ ID NO:5) and
CDR3 (GGFGSSYWYFDV, SEQ ID NO:6).
21. The method of claim 6, wherein the presence of the cancer
biomarker is predictive of the response to therapy with the
anti-Trop-2 ADC and therapeutic agent.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/707,404, filed Sep. 18, 2017, which was a
continuation of U.S. patent application Ser. No. 15/135,758 (now
U.S. Pat. No. 9,797,907), filed Apr. 22, 2016, which claimed the
benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent
Application 62/151,169, filed Apr. 22, 2015, the text of which is
incorporated herein by reference in its entirety.
SEQUENCE LISTING
[0002] The instant application contains a Sequence Listing which
has been submitted in ASCII format via EFS-Web and is hereby
incorporated by reference in its entirety. Said ASCII copy, created
on Apr. 21, 2016, is named IMM359US1_SL.txt and is 44,983 bytes in
size.
BACKGROUND OF THE INVENTION
Field of the Invention
[0003] This invention relates to methods and compositions for
isolating, detecting, diagnosing and/or characterizing Trop-2+
cancer cells, preferably from the circulation. The methods and
compositions utilize anti-Trop-2 antibodies, which may be
monovalent, bivalent or multivalent. In a preferred embodiment,
anti-Trop-2 antibodies are the sole anti-TAA (tumor-associated
antigen) capture antibodies utilized in the assay, which does not
include use of mixtures of antibodies against TAAs other than
Trop-2. In alternative embodiments, the capture antibody may be a
bispecific antibody comprising an anti-Trop-2 antibody or fragment
and a second antibody or fragment against a different TAA. More
preferably, the antibodies are rodent, chimeric, humanized or human
antibodies or antigen-binding fragments thereof. Expression of
Trop-2 in cancer cells may be assessed using known techniques,
including but not limited to binding of anti-Trop-2 antibodies as
detected by flow cytometry or immunohistochemistry, and
quantitative RT-PCR. Automated systems and devices that have been
developed to isolate and/or detect circulating tumor cells (CTCs),
including but not limited to the MagSweeper device (Illumina, Inc.,
San Diego, Calif.), LIQUIDBIOPSY.RTM. system (Cynvenio Biosystems,
Inc., Westlake Village, Calif.), CELLSEARCH.RTM. system (Vendex
LLC, Raritan, N.J.), GILUPI CELLCOLLECTOR.TM. (GILUPI GmbH,
Potsdam, Germany), APOSTREAM.RTM. system (Apocell, Houston, Tex.),
ONCOCEE.TM. microfluidic platform (BioCept Laboratories, San Diego,
Calif.), VerIFAST System (Casavant et al., 2013, Lab Chip 13:391-6;
2014, Lab Chip 14:99-105) or ISOFLUX.TM. system (Fluxion, South San
Francisco, Calif.) may be utilized in the practice of the claimed
methods. Most preferably, the anti-Trop-2 antibody is a murine,
chimeric or humanized RS7 (hRS7) antibody, comprising the light
chain CDR sequences CDR1 (KASQDVSIAVA, SEQ ID NO:1); CDR2 (SASYRYT,
SEQ ID NO:2); and CDR3 (QQHYITPLT, SEQ ID NO:3) and the heavy chain
CDR sequences CDR1 (NYGMN, SEQ ID NO:4); CDR2 (WINTYTGEPTYTDDFKG,
SEQ ID NO:5) and CDR3 (GGFGSSYWYFDV, SEQ ID NO:6). However, in
alternative embodiments other known anti-Trop-2 antibodies may be
utilized, as discussed below. The methods and compositions are
applicable for the enrichment, isolation, detection, diagnosis
and/or characterization of various metastatic Trop-2-expressing
cancers, such as breast (e.g., triple-negative breast cancer),
ovarian, cervical, endometrial, lung, prostate, colon, rectum,
stomach, esophageal, bladder, renal, pancreatic, thyroid,
epithelial, and head-and-neck cancers. Anti-Trop-2 antibodies may
be utilized in combination with one or more labeled detection
antibodies, or may be directly labeled by conjugation with at least
one diagnostic agent. Alternatively, a bispecific antibody may
comprise one binding site for Trop-2 and another binding site for a
hapten on a targetable construct, typically a small peptide labeled
with at least one diagnostic agent. In certain alternative
embodiments, detection of Trop-2.sup.+ CTCs may be followed by
therapeutic treatment of the Trop-2.sup.+ cancer, using anti-Trop-2
antibodies or fragments thereof. Preferably the antibody or
fragment is conjugated to at least one therapeutic agent, such as
antibodies, antibody fragments, drugs, toxins, nucleases, hormones,
immunomodulators, pro-apoptotic agents, anti-angiogenic agents,
boron compounds, photoactive agents or dyes or radioisotopes. More
preferably, the therapeutic agent is SN-38 or P2PDOX.
Related Art
[0004] Trop-2 (human trophoblast-cell-surface marker) is a cell
surface glycoprotein that was originally identified in normal and
malignant trophoblast cells (Lipinski et al., 1981, Proc Natl. Acad
Sci USA 78:5147-50). Trop-2 is highly expressed in most human
carcinomas, particularly in epithelial carcinomas and
adenocarcinomas, with reported low to restricted expression in
normal tissues (see, e.g., Cubas et al., 2010, Molec Cancer 9:253;
Stepan et al., 2011, J Histochem Cytochem 59:701-10; Varughese et
al., 2011, Am J Obst Gyn 205:567e-e7). Expression of Trop-2 is
associated with metastasis, increased tumor aggressiveness and
decreased patient survival (Cubas et al., 2010; Varughese et al.,
2011). Pathogenic effects of Trop-2 have been reported to be
mediated, at least in part, by the ERK 1/2 MAPK pathway (Cubas et
al., 2010).
[0005] It has been proposed that early in tumor progression, cancer
cells may be found in low concentration in the circulation (see,
e.g., Krishnamurthy et al., 2013, Cancer Medicine 2:226-33;
Alix-Panabieres & Pantel, 2013, Clin Chem 50:110-18; Wang et
al., Feb. 24, 2015, Int J Clin Oncol, Epub ahead of print). Due to
the relatively non-invasive nature of blood sample collection,
there has been great interest in the isolation and detection of
CTCs, to promote cancer diagnosis at an earlier stage of the
disease and as a predictor for tumor progression, disease prognosis
and/or responsiveness to drug therapy (see, e.g., Alix-Panabieres
& Pantel, 2013, Clin Chem 50:110-18; Winer-Jones et al., 2014,
PLoS One 9:e86717; U.S. Patent Appl. Publ. No. 2014/0357659).
[0006] Various techniques and apparatus have been developed to
isolate and/or detect circulating tumor cells. Several reviews of
the field have recently been published (see, e.g., Alix-Panabieres
& Pantel, 2013, Clin Chem 50:110-18; Joosse et al., 2014, EMBO
Mol Med 7:1-11; Truini et al., 2014, Fron Oncol 4:242). The
techniques have involved enrichment and/or isolation of CTCs,
generally using capture antibodies against an antigen expressed on
tumor cells, and separation with magnetic nanoparticles,
microfluidic devices, filtration, magnetic separation,
centrifugation, flow cytometry and/or cell sorting devices (e.g.,
Krishnamurthy et al., 2013, Cancer Medicine 2:226-33;
Alix-Panabieres & Pantel, 2013, Clin Chem 50:110-18; Joosse et
al., 2014, EMBO Mol Med 7:1-11; Truini et al., 2014, Fron Oncol
4:242; Powell et al., 2012, PLoS ONE 7:e33788; Winer-Jones et al.,
2014, PLoS One 9:e86717; Gupta et al., 2012, Biomicrofluidics
6:24133; Saucedo-Zeni et al., 2012, Int J Oncol 41:1241-50; Harb et
al., 2013, Transl Oncol 6:528-38). The enriched or isolated CTCs
may then be analyzed using a variety of known methods, as discussed
further below. Systems or apparatus that have been used for CTC
isolation and detection include the CELLSEARCH.RTM. system (e.g.,
Truini et al., 2014, Front Oncol 4:242), MagSweeper device (e.g.,
Powell et al., 2012, PLoS ONE 7:e33788), LIQUIDBIOPSY.RTM. system
(Winer-Jones et al., 2014, PLoS One 9:e86717), APOSTREAM.RTM.
system (e.g., Gupta et al., 2012, Biomicrofluidics 6:24133), GILUPI
CELLCOLLECTOR.TM. (e.g., Saucedo-Zeni et al., 2012, Int J Oncol
41:1241-50), and ISOFLUX.TM. system (Harb et al., 2013, Transl
Oncol 6:528-38).
[0007] To date, the only FDA-approved technology for CTC detection
involves the CELLSEARCH.RTM. platform (Veridex LLC, Raritan, N.J.),
which utilizes anti-EpCAM antibodies attached to magnetic
nanoparticles to capture CTCs. Detection of bound cells occurs with
fluorescent-labeled antibodies against cytokeratin (CK) and CD45.
Fluorescently labeled cells bound to magnetic particles are
separated out using a strong magnetic field and are counted by
digital fluorescence microscopy. The CELLSEARCH.RTM. system has
received FDA approval for detection of metastatic breast, prostate
and colorectal cancers.
[0008] Most CTC detection systems have focused on use of anti-EpCAM
capture antibodies (see, e.g., Truini et al., 2014, Front Oncol
4:242; Powell et al., 2012, PLoS ONE 7:e33788; Alix-Panabieres
& Pantel, 2013, Clin Chem 50:110-18; Lin et al., 2013, Biosens
Bioelectron 40:63-67; Wang et al., Feb. 24, 2015, Int J Clin Oncol
Epub ahead of print; Magbanua et al., 2015, Clin Cancer Res
21:1098-105; Harb et al., 2013, Transl Oncol 6:528-38). However,
not all metastatic tumors express EpCAM (see, e.g., Mikolajcyzyk et
al., 2011, J Oncol 2011:252361; Pecot et al., 2011, Cancer
Discovery 1:580-86; Gupta et al., 2012, Biomicrofluidics 6:24133).
Attempts have been made to utilize alternative schemes for
isolating and detecting EpCAM-negative CTCs, such as use of
antibody combinations against TAAs. Antibodies against as many as
10 different TAAs have been utilized in an attempt to increase
recovery of metastatic circulating tumor cells (e.g., Mikolajcyzyk
et al., 2011, J Oncol 2011:252361; Pecot et al., 2011, Cancer
Discovery 1:580-86; Krishnamurthy et al., 2013, Cancer Medicine
2:226-33; Winer-Jones et al., 2014, PLoS One 9:e86717).
[0009] Drawbacks exist to such approaches, including the complexity
of preparing and using large numbers of different antibodies and
their attachment to magnetic nanoparticles, microfluidic devices or
other separation technologies, as well as potential
cross-reactivity against normal cell populations when using a broad
spectrum of anti-tumor antibodies. A need exists in the art for
improved methods of isolating, detecting, diagnosing and/or
characterizing CTCs, using antibodies against a single TAA that is
expressed in a broad range of tumors.
SUMMARY
[0010] In various embodiments, the present invention concerns
enrichment, isolation, detection, diagnosis and/or characterization
of Trop-2-positive circulating tumor cells (CTCs) using anti-Trop-2
antibodies and/or antigen-binding fragments thereof. The
anti-Trop-2 antibody may be used to enrich and/or isolate tumor
cells from the circulation. Bound CTCs may be detected by a variety
of known techniques and/or apparatus, as discussed in detail below.
Any known method for detecting biomarkers of isolated CTCs may be
utilized, such as FISH, FACS, fluorescence microscopy, fluorescent
detection, flow cytometry, immunohistochemistry, microchip-based
systems, RT-PCR, ELISA, or any other technique known in the art for
detecting the presence of cancer cells.
[0011] In a specific embodiment, the anti-Trop-2 antibody may be a
murine, chimeric or humanized RS7 antibody (see, e.g., U.S. Pat.
No. 7,238,785, the Figures and Examples section of which are
incorporated herein by reference), comprising the light chain CDR
sequences CDR1 (KASQDVSIAVA, SEQ ID NO:1); CDR2 (SASYRYT, SEQ ID
NO:2); and CDR3 (QQHYITPLT, SEQ ID NO:3) and the heavy chain CDR
sequences CDR1 (NYGMN, SEQ ID NO:4); CDR2 (WINTYTGEPTYTDDFKG, SEQ
ID NO:5) and CDR3 (GGFGSSYWYFDV, SEQ ID NO:6). However, as
discussed below other anti-Trop-2 antibodies are known and may be
used.
[0012] The anti-Trop-2 antibody moiety may be a monoclonal
antibody, an antigen-binding antibody fragment, a bispecific or
multivalent antibody, or other antibody-based molecule. The
antibody can be of various isotypes, preferably human IgG1, IgG2,
IgG3 or IgG4, more preferably comprising human IgG1 hinge and
constant region sequences. The antibody or fragment thereof can be
a rodent, chimeric, a humanized, or a human antibody, as well as
variations thereof, such as half-IgG4 antibodies (referred to as
"unibodies"), as described by van der Neut Kolfschoten et al.
(Science 2007; 317:1554-1557). More preferably, the antibody or
fragment thereof may be designed or selected to comprise human
constant region sequences that belong to specific allotypes, such
as G1m3, G1m3,1, G1m3,2 or G1m3,1,2. More preferably, the allotype
is selected from the group consisting of the nG1m1, G1m3, nG1m1,2
and Km3 allotypes.
[0013] Where bispecific antibodies are used to capture CTCs, the
antibody may comprises at least one anti-Trop-2 antibody or
fragment thereof, and at least one antibody or fragment thereof
against a different TAA. Exemplary TAAs may include carbonic
anhydrase IX, CCL19, CCL21, CSAp, CD1, CD1a, CD2, CD3, CD4, CD5,
CD8, CD11A, CD14, CD15, CD16, CD18, CD19, IGF-1R, CD20, CD21, CD22,
CD23, CD25, CD29, CD30, CD32b, CD33, CD37, CD38, CD40, CD40L, CD45,
CD46, CD52, CD54, CD55, CD59, CD64, CD66a-e, CD67, CD70, CD74,
CD79a, CD80, CD83, CD95, CD126, CD133, CD138, CD147, CD154, CXCR4,
CXCR7, CXCL12, HIF-1-.alpha., AFP, PSMA, CEACAM5, CEACAM-6, c-met,
B7, ED-B of fibronectin, Factor H, FHL-1, Flt-3, folate receptor,
GROB, HMGB-1, hypoxia inducible factor (HIF), insulin-like growth
factor-1 (ILGF-1), IFN-.gamma., IFN-.alpha., IL-2, IL-4R, IL-6R,
IL-13R, IL-15R, IL-17R, IL-18R, IL-6, IL-8, IL-12, IL-15, IL-17,
IL-18, IL-25, IP-10, MAGE, mCRP, MCP-1, MIP-1A, MIP-1B, MIF, MUC1,
MUC2, MUC3, MUC4, MUC5ac, NCA-95, NCA-90, Ia, EGP-1, EGP-2, HLA-DR,
tenascin, Le(y), RANTES, T101, TAC, Tn antigen,
Thomson-Friedenreich antigens, tumor necrosis antigens,
TNF-.alpha., TRAIL receptor (R1 and R2), VEGFR, EGFR, P1GF,
complement factors C3, C3a, C3b, C5a, or C5. Preferably, the TAA is
selected from the group consisting of CEACAM5, MUC5ac, CD74,
HLA-DR, CSAp, AFP (alpha-fetoprotein), HER2, vimentin, EGFR,
IGF-1R, PD-L1 and PD-L2.
[0014] Because the detected tumors will be Trop-2-positive, they
may be treated with anti-Trop-2 antibodies, such as anti-Trop-2
antibody-drug conjugates (ADCs). An anti-Trop-2 antibody may
initially be used to detect and/or quantify expression or gene copy
number of Trop-2 in the CTC. Such analysis may be used to predict
response to therapeutic anti-Trop-2 antibodies, as well as to
monitor response of the tumor(s) to treatment. As discussed below,
immunoconjugates of anti-Trop-2 antibodies may include any known
therapeutic agent, such as a chemotherapeutic agent. A number of
cytotoxic drugs of use for cancer treatment are well-known in the
art and any such known drug may be conjugated to the antibody of
interest. In a preferred embodiment, the drug conjugated to the
antibody is a camptothecin or anthracycline, most preferably SN-38
or a pro-drug form of 2-pyrrolinodoxorubicin (2-PDox) (see, e.g.,
U.S. Pat. Nos. 8,877,202 and 8,750,496, the Figures and Examples
section of each incorporated herein by reference). The drug to be
conjugated to the anti-Trop-2 antibody or antibody fragment may be
selected from the group consisting of an anthracycline, a
camptothecin, a tubulin inhibitor, a maytansinoid, a calicheamycin,
an auristatin, a nitrogen mustard, an ethylenimine derivative, an
alkyl sulfonate, a nitrosourea, a triazene, a folic acid analog, a
taxane, a COX-2 inhibitor, a pyrimidine analog, a purine analog, an
antibiotic, an enzyme inhibitor, an epipodophyllotoxin, a platinum
coordination complex, a vinca alkaloid, a substituted urea, a
methyl hydrazine derivative, an adrenocortical suppressant, a
hormone antagonist, an antimetabolite, an alkylating agent, an
antimitotic, an anti-angiogenic agent, a tyrosine kinase inhibitor,
an mTOR inhibitor, a heat shock protein (HSP90) inhibitor, a
proteosome inhibitor, an HDAC inhibitor, a pro-apoptotic agent, and
a combination thereof.
[0015] The anti-Trop-2 antibodies are of use for detection,
diagnosis, characterization and/or treatment of Trop-2 expressing
cancers, such as breast, ovarian, cervical, endometrial, lung,
prostate, colon, rectum, stomach, esophageal, bladder, renal,
pancreatic, thyroid, epithelial or head-and-neck cancers. The
methods and compositions may be of particular use for detection
and/or treatment of metastatic colorectal cancer, triple-negative
breast cancer, HER+, ER+, progesterone+breast cancer, metastatic
non-small-cell lung cancer (NSCLC), metastatic small-cell lung
cancer (SCLC), metastatic pancreatic cancer, metastatic renal cell
carcinoma, metastatic gastric cancer, metastatic esophageal cancer,
metastatic urothelial cancer, or metastatic prostate cancer.
DETAILED DESCRIPTION
[0016] Definitions
[0017] Unless otherwise specified, "a" or "an" means one or
more.
[0018] As used herein, "about" means plus or minus 10%. For
example, "about 100" would include any number between 90 and
110.
[0019] An antibody, as described herein, refers to a full-length
(i.e., naturally occurring or formed by normal immunoglobulin gene
fragment recombinatorial processes) immunoglobulin molecule (e.g.,
an IgG antibody) or an immunologically active (i.e., specifically
binding) portion of an immunoglobulin molecule, like an antibody
fragment.
[0020] An antibody fragment is a portion of an antibody such as
F(ab').sub.2, Fab', Fab, Fv, sFv and the like. Antibody fragments
may also include single domain antibodies and IgG4 half-molecules,
as discussed below. Regardless of structure, an antibody fragment
binds with the same antigen that is recognized by the full-length
antibody. The term "antibody fragment" also includes isolated
fragments consisting of the variable regions of antibodies, such as
the "Fv" fragments consisting of the variable regions of the heavy
and light chains and recombinant single chain polypeptide molecules
in which light and heavy variable regions are connected by a
peptide linker ("scFv proteins").
[0021] A chimeric antibody is a recombinant protein that contains
the variable domains including the complementarity determining
regions (CDRs) of an antibody derived from one species, preferably
a rodent antibody, while the constant domains of the antibody
molecule are derived from those of a human antibody. For veterinary
applications, the constant domains of the chimeric antibody may be
derived from that of other species, such as a cat or dog.
[0022] A humanized antibody is a recombinant protein in which the
CDRs from an antibody from one species; e.g., a rodent antibody,
are transferred from the heavy and light variable chains of the
rodent antibody into human heavy and light variable domains (e.g.,
framework region sequences). The constant domains of the antibody
molecule are derived from those of a human antibody. In certain
embodiments, a limited number of framework region amino acid
residues from the parent (rodent) antibody may be substituted into
the human antibody framework region sequences.
[0023] A human antibody is, e.g., an antibody obtained from
transgenic mice that have been "engineered" to produce specific
human antibodies in response to antigenic challenge. In this
technique, elements of the human heavy and light chain loci are
introduced into strains of mice derived from embryonic stem cell
lines that contain targeted disruptions of the endogenous murine
heavy chain and light chain loci. The transgenic mice can
synthesize human antibodies specific for particular antigens, and
the mice can be used to produce human antibody-secreting
hybridomas. Methods for obtaining human antibodies from transgenic
mice are described by Green et al., Nature Genet. 7:13 (1994),
Lonberg et al., Nature 368:856 (1994), and Taylor et al., Int.
Immun. 6:579 (1994). A fully human antibody also can be constructed
by genetic or chromosomal transfection methods, as well as phage
display technology, all of which are known in the art. See for
example, McCafferty et al., Nature 348:552-553 (1990) for the
production of human antibodies and fragments thereof in vitro, from
immunoglobulin variable domain gene repertoires from unimmunized
donors. In this technique, antibody variable domain genes are
cloned in-frame into either a major or minor coat protein gene of a
filamentous bacteriophage, and displayed as functional antibody
fragments on the surface of the phage particle. Because the
filamentous particle contains a single-stranded DNA copy of the
phage genome, selections based on the functional properties of the
antibody also result in selection of the gene encoding the antibody
exhibiting those properties. In this way, the phage mimics some of
the properties of the B cell. Phage display can be performed in a
variety of formats, for review, see e.g. Johnson and Chiswell,
Current Opinion in Structural Biology 3:5564-571 (1993). Human
antibodies may also be generated by in vitro activated B cells. See
U.S. Pat. Nos. 5,567,610 and 5,229,275, the Examples section of
which are incorporated herein by reference.
[0024] A "diagnostic agent" is an atom, molecule, or compound that
is useful in diagnosing a disease. Useful diagnostic agents
include, but are not limited to, radioisotopes, dyes, contrast
agents, luminescent agents, chemiluminescent agents, fluorescent
compounds or molecules and enhancing agents (e.g., paramagnetic
ions). Preferably, the diagnostic agents are selected from the
group consisting of radioisotopes, enhancing agents, and
fluorescent compounds.
[0025] A therapeutic agent is a compound, molecule or atom which is
administered separately, concurrently or sequentially with an
antibody moiety or conjugated to an antibody moiety, i.e., antibody
or antibody fragment, or a subfragment, and is useful in the
treatment of a disease. Examples of therapeutic agents include
antibodies, antibody fragments, drugs, toxins, nucleases, hormones,
immunomodulators, pro-apoptotic agents, anti-angiogenic agents,
boron compounds, photoactive agents or dyes and radioisotopes.
Therapeutic agents of use are described in more detail below.
[0026] An immunoconjugate is an antibody, antibody fragment or
fusion protein conjugated to at least one therapeutic and/or
diagnostic agent.
[0027] A multispecific antibody is an antibody that can bind
simultaneously to at least two targets that are of different
structure, e.g., two different antigens, two different epitopes on
the same antigen, or a hapten and/or an antigen or epitope.
Multispecific, multivalent antibodies are constructs that have more
than one binding site, and the binding sites are of different
specificity.
[0028] A bispecific antibody is an antibody that can bind
simultaneously to two different targets. Bispecific antibodies
(bsAb) and bispecific antibody fragments (bsFab) may have at least
one arm that specifically binds to, for example, a tumor-associated
antigen and at least one other arm that specifically binds to a
targetable conjugate that bears a therapeutic or diagnostic agent.
A variety of bispecific fusion proteins can be produced using
molecular engineering.
FIGURE LEGENDS
[0029] FIG. 1. Analysis of Trop-2 copy number by FISH. MCF-7
(Trop-2 positive) cells were analyzed by FISH. Trop-2 copy number
was determined using anti-Trop-2 and anti-chromosome-1 specific
probes (Empire Genomics, Buffalo, N.Y.).
[0030] FIG. 2. Analysis of Trop-2 copy number by FISH. A549 (Trop-2
negative) cells were analyzed by FISH. Trop-2 copy number was
determined using anti-Trop-2 and anti-chromosome-1 specific probes
(Empire Genomics, Buffalo, N.Y.).
[0031] FIG. 3. Analysis of topoisomerase-I copy number by FISH.
MCF-7 cells were analyzed by FISH. Topoisomerase I (TOP1) copy
number was determined using anti-TOP1 and anti-chromosome-20
specific probes (ABNOVA.RTM., Taipei, Taiwan).
[0032] FIG. 4. Analysis of topoisomerase-I copy number by FISH.
A549 cells were analyzed by FISH. Topoisomerase I (TOP1) copy
number was determined using anti-TOP1 and anti-chromosome-20
specific probes (ABNOVA.RTM., Taipei, Taiwan).
ANTI-TROP-2 ANTIBODIES
[0033] The subject methods and compositions for CTC isolation
and/or detection utilize at least one antibody or fragment thereof
that binds to Trop-2, including rodent, chimeric, human or
humanized antibodies. In a specific preferred embodiment, the
anti-Trop-2 antibody may be a humanized RS7 antibody (see, e.g.,
U.S. Pat. No. 7,238,785, incorporated herein by reference in its
entirety), comprising the light chain CDR sequences CDR1
(KASQDVSIAVA, SEQ ID NO:1); CDR2 (SASYRYT, SEQ ID NO:2); and CDR3
(QQHYITPLT, SEQ ID NO:3) and the heavy chain CDR sequences CDR1
(NYGMN, SEQ ID NO:4); CDR2 (WINTYTGEPTYTDDFKG, SEQ ID NO:5) and
CDR3 (GGFGSSYWYFDV, SEQ ID NO:6).
[0034] The RS7 antibody was a murine IgG.sub.1 raised against a
crude membrane preparation of a human primary squamous cell lung
carcinoma. (Stein et al., Cancer Res. 50: 1330, 1990) The RS7
antibody recognizes a 46-48 kDa glycoprotein, characterized as
cluster 13. (Stein et al., Int. J. Cancer Supp. 8:98-102, 1994) The
antigen was designated as EGP-1 (epithelial glycoprotein-1), but is
also referred to as Trop-2.
[0035] Trop-2 is a type-I transmembrane protein and has been cloned
from both human (Fornaro et al., Int J Cancer 1995; 62:610-8) and
mouse cells (Sewedy et al., Int J Cancer 1998; 75:324-30). In
addition to its role as a tumor-associated calcium signal
transducer (Ripani et al., Int J Cancer 1998; 76:671-6), the
expression of human Trop-2 was shown to be necessary for
tumorigenesis and invasiveness of colon cancer cells, which could
be effectively reduced with a polyclonal antibody against the
extracellular domain of Trop-2 (Wang et al., Mol Cancer Ther 2008;
7:280-5). Trop-2 is highly expressed in the vast majority of human
tumors and animal models of cancer (McDougall et al., 2015, Dev Dyn
244:99-109).
[0036] The utility of Trop-2 as a marker for solid cancers (Cubas
et al., Biochim Biophys Acta 2009; 1796:309-14) is attested by
further reports that documented the clinical significance of
overexpressed Trop-2 in breast (Huang et al., Clin Cancer Res 2005;
11:4357-64), colorectal (Ohmachi et al., Clin Cancer Res 2006;
12:3057-63; Fang et al., Int J Colorectal Dis 2009; 24:875-84), and
oral squamous cell (Fong et al., Modern Pathol 2008; 21:186-91)
carcinomas. The latest evidence that prostate basal cells
expressing high levels of Trop-2 are enriched for in vitro and in
vivo stem-like activity is particularly noteworthy (Goldstein et
al., Proc Natl Acad Sci USA 2008; 105:20882-7).
[0037] Flow cytometry and immunohistochemical staining studies have
shown that the RS7 MAb detects antigen on a variety of tumor types,
with limited binding to normal human tissue (Stein et al., 1990).
Trop-2 is expressed primarily by carcinomas such as carcinomas of
the lung, stomach, urinary bladder, breast, ovary, uterus, and
prostate. Localization and therapy studies using radiolabeled
murine RS7 MAb in animal models have demonstrated tumor targeting
and therapeutic efficacy (Stein et al., 1990; Stein et al., 1991).
Drug-conjugated RS7 MAb in animal models also have shown targeting
and therapeutic efficacy of human cancer xenografts (Cardillo et
al., Clinical Cancer Res., 17:3157-69, 2011).
[0038] Strong RS7 staining has been demonstrated in tumors from the
lung, breast, bladder, ovary, uterus, stomach, and prostate. (Stein
et al., Int. J. Cancer 55:938, 1993) The lung cancer cases
comprised both squamous cell carcinomas and adenocarcinomas. (Stein
et al., Int. J. Cancer 55:938, 1993) Both cell types stained
strongly, indicating that the RS7 antibody does not distinguish
between histologic classes of non-small-cell carcinoma of the
lung.
[0039] While the hRS7 antibody is preferred, other anti-Trop-2
antibodies are known and/or publicly available and in alternative
embodiments may be utilized in the subject methods and
compositions. While humanized or human antibodies are preferred for
reduced immunogenicity, in alternative embodiments a chimeric
antibody may be of use, while rodent MAbs can be useful for
in-vitro and ex-vivo studies. As discussed below, methods of
antibody humanization are well known in the art and may be utilized
to convert an available murine or chimeric antibody into a
humanized form.
[0040] Anti-Trop-2 antibodies are commercially available from a
number of sources and include LS-C126418, LS-C178765, LS-C126416,
LS-C126417 (LifeSpan BioSciences, Inc., Seattle, Wash.);
10428-MM01, 10428-MM02, 10428-R001, 10428-R030 (Sino Biological
Inc., Beijing, China); MR54 (eBioscience, San Diego, Calif.);
sc-376181, sc-376746, Santa Cruz Biotechnology (Santa Cruz,
Calif.); MM0588-49D6, (Novus Biologicals, Littleton, Colo.);
ab79976, and ab89928 (ABCAM.RTM., Cambridge, Mass.).
[0041] Other anti-Trop-2 antibodies have been disclosed in the
patent literature. For example, U.S. Publ. No. 2013/0089872
discloses anti-Trop-2 antibodies K5-70 (Accession No. FERM
BP-11251), K5-107 (Accession No. FERM BP-11252), K5-116-2-1
(Accession No. FERM BP-11253), T6-16 (Accession No. FERM BP-11346),
and T5-86 (Accession No. FERM BP-11254), deposited with the
International Patent Organism Depositary, Tsukuba, Japan. U.S. Pat.
No. 5,840,854 disclosed the anti-Trop-2 monoclonal antibody BR110
(ATCC No. HB11698). U.S. Pat. No. 7,420,040 disclosed an
anti-Trop-2 antibody produced by hybridoma cell line AR47A6.4.2,
deposited with the IDAC (International Depository Authority of
Canada, Winnipeg, Canada) as accession number 141205-05. U.S. Pat.
No. 7,420,041 disclosed an anti-Trop-2 antibody produced by
hybridoma cell line AR52A301.5, deposited with the IDAC as
accession number 141205-03. U.S. Publ. No. 2013/0122020 disclosed
anti-Trop-2 antibodies 3E9, 6G11, 7E6, 15E2, 18B1. Hybridomas
encoding a representative antibody were deposited with the American
Type Culture Collection (ATCC), Accession Nos. PTA-12871 and
PTA-12872. U.S. Pat. No. 8,715,662 discloses anti-Trop-2 antibodies
produced by hybridomas deposited at the AID-ICLC (Genoa, Italy)
with deposit numbers PD 08019, PD 08020 and PD 08021. U.S. Patent
Application Publ. No. 20120237518 discloses anti-Trop-2 antibodies
77220, KM4097 and KM4590. U.S. Pat. No. 8,309,094 (Wyeth) discloses
antibodies A1 and A3, identified by sequence listing. The Examples
section of each patent or patent application cited above in this
paragraph is incorporated herein by reference. For non-patent
publications, Lipinski et al. (1981, Proc Natl. Acad Sci USA,
78:5147-50) disclosed anti-Trop-2 antibodies 162-25.3 and 162-46.2.
More recently, the Pr1E11 anti-Trop-2 antibody was reported to
recognize a unique epitope on Trop-2 (Ikeda et al., Biochem Biophys
Res Comm 458:877-82).
[0042] Numerous anti-Trop-2 antibodies are known in the art and/or
publicly available. As discussed below, methods for preparing
antibodies against known antigens were routine in the art. The
sequence of the human Trop-2 protein was also known in the art
(see, e.g., GenBank Accession No. CAA54801.1). Methods for
producing humanized, human or chimeric antibodies were also known.
The person of ordinary skill, reading the instant disclosure in
light of general knowledge in the art, would have been able to make
and use the genus of anti-Trop-2 antibodies.
[0043] None of the prior studies discussed above contained any
disclosure of the use of anti-Trop-2 antibodies for isolating or
detecting Trop-2 positive CTCs. A need exists for compositions and
methods for enriching, isolating, detecting, diagnosing and/or
characterizing Trop-2 positive CTCs.
[0044] Isolation and Detection of Circulating Tumor Cells
[0045] The anti-Trop-2 antibodies may be utilized to enrich,
isolate, detect and/or diagnose Trop-2 positive CTCs using any
known technology for CTC isolation and detection. Numerous systems
have been developed and are commercially available for CTC
detection. Although the majority were developed using specific
anti-EpCAM antibodies, the compositions and methods may be modified
to utilize anti-Trop-2 antibodies instead. Thus, isolation and
detection of Trop-2 positive CTCs may be performed using any such
known system, or more traditional methods of cell isolation and
detection. Non-limiting examples of such known techniques are
discussed below.
[0046] The present invention may be used with an affinity-based
enrichment step, as well as methods without an enrichment steps,
such as MAINTRAC.RTM. (Pachmann et al. 2005, Breast Cancer Res, 7:
R975). Methods that use a magnetic device for affinity-based
enrichment, include the CELLSEARCH.RTM. system (Vendex), the
LIQUIDBIOPSY.RTM. platform (Cynvenio Biosystems) and the MagSweeper
device (Talasaz et al, PNAS, 2009, 106: 3970). Methods that do not
use a magnetic device for affinity-based enrichment, include a
variety of fabricated microfluidic devices, such as CTC-chips
(Stott et al. 2010, Sci Transl Med, 2: 25ra23), HB-chips (Stott et
al, 2010, PNAS, 107: 18392), NanoVelcro chips (Lu et al., 2013,
Methods, 64: 144), GEDI microdevice (Kirby et al., 2012, PLoS ONE,
7: e35976), and Biocept's ONCOCEE.TM. technology (Pecot et al.,
2011, Cancer Discov, 1: 580).
[0047] Use of the FDA-approved CELLSEARCH.RTM. system for CTC
detection in non-small cell and small cell lung cancer patients is
discussed in Truini et al. (2014, Front Oncol 4:242). A 7.5 ml
sample of peripheral blood is mixed with magnetic iron
nanoparticles coated with an nanti-EpCAM antibody. A strong
magnetic field is used to separate EpCAM positive from
EpCAM-negative cells. Detection of bound CTCs was performed using
fluorescently labeled anti-CK and anti-CD45 antibodies, along with
DAPI (4',6'diamidino-2-phynlindole) fluorescent labeling of cell
nuclei. CTCs were identified by fluorescent detection as CK
positive, CD45 negative and DAPI positive.
[0048] The VerIFAST system was used for diagnosis and
pharmacodynamic analysis of circulating tumor cells (CTCs) in
non-small cell lung cancer (NSCLC) (Casavant et al., 2013, Lab Chip
13:391-6; 2014, Lab Chip 14:99-105). The VerIFAST platform utilizes
the relative dominance of surface tension over gravity in the
microscale to load immiscible phases side by side. This pins
aqueous and oil fields in adjacent chambers to create a virtual
filter between two aqueous wells (Casavant et al., 2013, Lab Chip
13:391-6). Using paramagnetic particles (PMPs) with attached
antibody or other targeting moieties, specific cell populations can
be targeted and isolated from complex backgrounds through a simple
traverse of the oil barrier. In the NSCLC example, streptavidin was
conjugated to DYNABEADS.RTM. FLOWCOMP.TM. PMPs (Life Technologies,
USA) and cells were captured using biotinylated anti-EpCAM
antibody. A handheld magnet was used to transfer CTCs bound to PMPs
between aqueous chambers. Collected CTCs were released with PMP
release buffer (DYNABEADS.RTM.) and stained for EpCAM, EGFR or
transcription termination factor (TTF-1).
[0049] The VerIFAST platform integrates a microporous membrane into
an aqueous chamber to enable multiple fluid transfers without the
need for cell transfer or centrifugation. With physical
characteristic scales enabling high precision relative to
macroscale techniques, such microfluidic techniques are well
adapted to capture and assess CTCs with minimal sample loss. The
VerIFAST platform effectively captured CTCs from blood of NSCLC
patients.
[0050] The GILUPI CELLCOLLECTOR.TM. (Saucedo-Zeni et al., 2012, Int
J Oncol 41:1241-50) is based on a functionalized medical Seldinger
guidewire (FSMW) coated with chimeric anti-EpCAM antibody. The
guidewire was functionalized with a polycarboxylate hydrogel layer
that was activated with EDC and NHS, allowing covalent bonding of
antibody. The antibody-coated FSMW was inserted in the cubital
veins of breast cancer or NSCLC lung cancer patients through a
standard venous cannula for 30 minutes. Following binding of cells
to the guidewire, CTCs were identified by immunocytochemical
staining of EpCAM and/or cytokeratins and nuclear staining.
Fluorescent labeling was analyzed with an Axio Imager.A1m
microscope (Zeiss, Jena, Germany) equipped with an AxioCam digital
camera system and AxioVision 4.6 software. The FSMW system was
capable of enriching EpCAM-positive CTCs from 22 of 24 patients
tested, including those with early stage cancer in which distant
metasteses had not yet been diagnosed. No CTCs were detected in
healthy volunteers. An advantage of the FSMW system is that it is
not limited by the volume of ex vivo blood samples that may be
processed using alternative methodologies, such as the
CELLSEARCH.RTM. system. Estimated blood volume in contact with the
FSMW during the 30 minute exposure was 1.5 to 3 liters.
[0051] The MagSweeper device (e.g., Powell et al., 2012, PLoS ONE
7:e33788) is another system utilized antibody-coated magnetic
particles for CTC detection. Nine milliliters of whole blood was
mixed ex vivo for 1 hr at RT with 4.5 .mu.M DYNABEADS.RTM.
(Invitrogen, Life Technologies, Grand Island, N.Y.) coated with the
BerEP4 anti-EpCAM antibody. After dilution with PBS, cells bound to
DYNABEADS.RTM. were captured by a sweeping magnetic device
(MagSweeper, see FIG. 1 of Powell et al., 2012). Two cycles of
capture-wash-release were performed, using a controlled shear force
that released non-specifically bound leukocytes and RBCs. Captured
cells were released into fresh buffer and examined using an Axio
Observer A1 inverted microscope (Zeiss). Single CTCs were manually
aspirated and stored frozen, prior to analysis of expression of 87
genes by chip based high-throughput qRT-PCR.
[0052] Gupta et al. (2012, Biomicrofluidics 6:24133) discussed use
of the APOSTREAM.TM. dielectrophoretic device for CTC collection
and analysis. A microfluidic flow chamber is used with
dielectrophoretic (DEP) technology to capture CTCs (see FIG. 1,
Gupta et al., 2012). The system may be operated in continuous mode
for flow-through isolation and enrichment of CTCs from peripheral
blood. DEP sorts cells with distinct biophysical characteristics by
exploiting the frequency-dependent dielectric properties of
different cell types, arising from differences in morphologic
properties and electrical conductivity. These differences result in
differential frequency-dependent migration of CTCs and normal cells
in the microfluidic chamber. At an AC frequency in the range of
45-85 kHz, cancer cells experience a positive (attractive) DEP
force, which causes them to migrate towards the electrode plane and
away from the hydrodynamic flow through the chamber. At the same
frequency, normal cells experience a negative (repulsive) DEP
force, which moves them into the hydrodynamic flow velocity profile
and out of the chamber. A collection port is used to remove
separated CTCs for further analysis. For the initial optimization
study, cultured cancer cells were spiked into normal blood
mononuclear cells and were recovered with over a 70% efficiency.
Although the APOSTREAM.TM. system disclosed by Gupta does not use
capture antibodies, the subject anti-Trop-2 antibodies may
potentially be utilized to increase the efficiency of CTC
separation and/or for post-separation characterization of the
isolated CTCs.
[0053] Winer-Jones et al. (2014, PLoS One 9:e86717) discussed use
of the LIQUIDBIOPSY.RTM. system for isolation and characterization
of CTCs. The LIQUIDBIOPSY.RTM. system uses high throughput sheath
flow microfluidics through a flow cell, combined with anti-EpCAM
antibodies as a capture agent. Biotinylated anti-EpCAM was attached
to streptavidin-coated IMAG.TM. beads (BD, Franklin Lakes, N.J.)
and mixed with blood samples, containing spiked tumor cells labeled
with CFSE or FITC. Normal nucleated cells were labeled with DAPI.
After antibody binding, the blood samples were processed on the CTC
flow cell, attached to a glass slide. An external magnetic field is
used to capture magnetic-bead bound CTCs on the glass surface,
separating them from the laminar flow containing normal cells.
Captured cells were counted using an Eclipse E80i fluorescent
microscope (Nikon Instruments, Melville, N.Y.).
[0054] The person of ordinary skill will realize that any of these
systems, or any other known system for CTC enrichment and/or
isolation, may be used with the subject anti-Trop-2 antibodies for
enrichment, isolation, detection and/or characterization of CTCs.
Where an anti-Trop-2 capture antibody is utilized, the bound CTCs
may be detected and/or characterized using labeled antibodies
against a different Trop-2 epitope, or against other known
tumor-associated antigens, including but not limited to carbonic
anhydrase IX, CCL19, CCL21, CSAp, CD1, CD1a, CD2, CD3, CD4, CD5,
CD8, CD11A, CD14, CD15, CD16, CD18, CD19, IGF-1R, CD20, CD21, CD22,
CD23, CD25, CD29, CD30, CD32b, CD33, CD37, CD38, CD40, CD40L, CD45,
CD46, CD52, CD54, CD55, CD59, CD64, CD66a-e, CD67, CD70, CD74,
CD79a, CD80, CD83, CD95, CD126, CD133, CD138, CD147, CD154, CXCR4,
CXCR7, CXCL12, HIF-1-.alpha., AFP, PSMA, CEACAM5, CEACAM-6, c-met,
B7, ED-B of fibronectin, Factor H, FHL-1, Flt-3, folate receptor,
GROB, HMGB-1, hypoxia inducible factor (HIF), insulin-like growth
factor-1 (ILGF-1), IFN-.gamma., IFN-.alpha., IFN-.beta., IL-2,
IL-4R, IL-6R, IL-13R, IL-15R, IL-17R, IL-18R, IL-6, IL-8, IL-12,
IL-15, IL-17, IL-18, IL-25, IP-10, MAGE, mCRP, MCP-1, MIP-1A,
MIP-1B, MIF, MUC1, MUC2, MUC3, MUC4, MUC5ac, NCA-95, NCA-90, Ia,
EGP-1, EGP-2, HLA-DR, tenascin, Le(y), RANTES, T101, TAC, Tn
antigen, Thomson-Friedenreich antigens, tumor necrosis antigens,
TNF-.alpha., TRAIL receptor (R1 and R2), VEGFR, EGFR, P1GF,
complement factors C3, C3a, C3b, C5a, and C5.
[0055] Antibody Preparation
[0056] Techniques for preparing monoclonal antibodies against
virtually any target antigen, such as Trop-2, are well known in the
art. See, for example, Kohler and Milstein, Nature 256: 495 (1975),
and Coligan et al. (eds.), CURRENT PROTOCOLS IN IMMUNOLOGY, VOL. 1,
pages 2.5.1-2.6.7 (John Wiley & Sons 1991). Briefly, monoclonal
antibodies can be obtained by injecting mice with a composition
comprising an antigen, removing the spleen to obtain B-lymphocytes,
fusing the B-lymphocytes with myeloma cells to produce hybridomas,
cloning the hybridomas, selecting positive clones which produce
antibodies to the antigen, culturing the clones that produce
antibodies to the antigen, and isolating the antibodies from the
hybridoma cultures.
[0057] MAbs can be isolated and purified from hybridoma cultures by
a variety of well-established techniques. Such isolation techniques
include affinity chromatography with Protein-A or Protein-G
Sepharose, size-exclusion chromatography, and ion-exchange
chromatography. See, for example, Coligan at pages 2.7.1-2.7.12 and
pages 2.9.1-2.9.3. Also, see Baines et al., "Purification of
Immunoglobulin G (IgG)," in METHODS IN MOLECULAR BIOLOGY, VOL. 10,
pages 79-104 (The Humana Press, Inc. 1992).
[0058] After the initial raising of antibodies to the immunogen,
the antibodies can be sequenced and subsequently prepared by
recombinant techniques. Humanization and chimerization of murine
antibodies and antibody fragments are well known to those skilled
in the art, as discussed below.
[0059] Chimeric Antibodies
[0060] A chimeric antibody is a recombinant protein in which the
variable regions of a human antibody have been replaced by the
variable regions of, for example, a mouse antibody, including the
complementarity-determining regions (CDRs) of the mouse antibody.
Chimeric antibodies exhibit decreased immunogenicity and increased
stability when administered to a subject. General techniques for
cloning murine immunoglobulin variable domains are disclosed, for
example, in Orlandi et al., Proc. Nat'l Acad. Sci. USA 6: 3833
(1989). Techniques for constructing chimeric antibodies are well
known to those of skill in the art. As an example, Leung et al.,
Hybridoma 13:469 (1994), produced an LL2 chimera by combining DNA
sequences encoding the V.sub..kappa. and V.sub.H domains of murine
LL2, an anti-CD22 monoclonal antibody, with respective human
.kappa. and IgG.sub.1 constant region domains.
[0061] Humanized Antibodies
[0062] Techniques for producing humanized MAbs are well known in
the art (see, e.g., Jones et al., Nature 321: 522 (1986), Riechmann
et al., Nature 332: 323 (1988), Verhoeyen et al., Science 239: 1534
(1988), Carter et al., Proc. Nat'l Acad. Sci. USA 89: 4285 (1992),
Sandhu, Crit. Rev. Biotech. 12: 437 (1992), and Singer et al., J.
Immun. 150: 2844 (1993)). A chimeric or murine monoclonal antibody
may be humanized by transferring the mouse CDRs from the heavy and
light variable chains of the mouse immunoglobulin into the
corresponding variable domains of a human antibody. The mouse
framework regions (FR) in the chimeric monoclonal antibody are also
replaced with human FR sequences. As simply transferring mouse CDRs
into human FRs often results in a reduction or even loss of
antibody affinity, additional modification might be required in
order to restore the original affinity of the murine antibody. This
can be accomplished by the replacement of one or more human
residues in the FR regions with their murine counterparts to obtain
an antibody that possesses good binding affinity to its epitope.
See, for example, Tempest et al., Biotechnology 9:266 (1991) and
Verhoeyen et al., Science 239: 1534 (1988). Preferred residues for
substitution include FR residues that are located within 1, 2, or 3
Angstroms of a CDR residue side chain, that are located adjacent to
a CDR sequence, or that are predicted to interact with a CDR
residue.
[0063] Human Antibodies
[0064] Methods for producing fully human antibodies using either
combinatorial approaches or transgenic animals transformed with
human immunoglobulin loci are known in the art (e.g., Mancini et
al., 2004, New Microbiol. 27:315-28; Conrad and Scheller, 2005,
Comb. Chem. High Throughput Screen. 8:117-26; Brekke and Loset,
2003, Curr. Opin. Pharmacol. 3:544-50). A fully human antibody also
can be constructed by genetic or chromosomal transfection methods,
as well as phage display technology, all of which are known in the
art. See for example, McCafferty et al., Nature 348:552-553 (1990).
Where antibodies are to be utilized in vivo, for example in tumor
therapy following detection of a Trop-2 positive cancer, such fully
human antibodies are expected to exhibit even fewer side effects
than chimeric or humanized antibodies and to function in vivo as
essentially endogenous human antibodies.
[0065] In one alternative, the phage display technique may be used
to generate human antibodies (e.g., Dantas-Barbosa et al., 2005,
Genet. Mol. Res. 4:126-40). Human antibodies may be generated from
normal humans or from humans that exhibit a particular disease
state, such as cancer (Dantas-Barbosa et al., 2005). The advantage
to constructing human antibodies from a diseased individual is that
the circulating antibody repertoire may be biased towards
antibodies against disease-associated antigens.
[0066] In one non-limiting example of this methodology,
Dantas-Barbosa et al. (2005) constructed a phage display library of
human Fab antibody fragments from osteosarcoma patients. Generally,
total RNA was obtained from circulating blood lymphocytes (Id.).
Recombinant Fab were cloned from the .mu., .gamma. and .kappa.
chain antibody repertoires and inserted into a phage display
library (Id.). RNAs were converted to cDNAs and used to make Fab
cDNA libraries using specific primers against the heavy and light
chain immunoglobulin sequences (Marks et al., 1991, J. Mol. Biol.
222:581-97). Library construction was performed according to
Andris-Widhopf et al. (2000, In: Phage Display Laboratory Manual,
Barbas et al. (eds), 1.sup.st edition, Cold Spring Harbor
Laboratory Press, Cold Spring Harbor, N.Y. pp. 9.1 to 9.22). The
final Fab fragments were digested with restriction endonucleases
and inserted into the bacteriophage genome to make the phage
display library. Such libraries may be screened by standard phage
display methods, as known in the art. Phage display can be
performed in a variety of formats, for their review, see e.g.
Johnson and Chiswell, Current Opinion in Structural Biology
3:5564-571 (1993).
[0067] Human antibodies may also be generated by in vitro activated
B-cells. See U.S. Pat. Nos. 5,567,610 and 5,229,275, incorporated
herein by reference in their entirety. The skilled artisan will
realize that these techniques are exemplary and any known method
for making and screening human antibodies or antibody fragments may
be utilized.
[0068] In another alternative, transgenic animals that have been
genetically engineered to produce human antibodies may be used to
generate antibodies against essentially any immunogenic target,
using standard immunization protocols. Methods for obtaining human
antibodies from transgenic mice are disclosed by Green et al.,
Nature Genet. 7:13 (1994), Lonberg et al., Nature 368:856 (1994),
and Taylor et al., Int. Immun. 6:579 (1994). A non-limiting example
of such a system is the XenoMouse.RTM. (e.g., Green et al., 1999,
J. Immunol. Methods 231:11-23, incorporated herein by reference)
from Abgenix (Fremont, Calif.). In the XenoMouse.RTM. and similar
animals, the mouse antibody genes have been inactivated and
replaced by functional human antibody genes, while the remainder of
the mouse immune system remains intact.
[0069] The XenoMouse.RTM. was transformed with germline-configured
YACs (yeast artificial chromosomes) that contained portions of the
human IgH and Igkappa loci, including the majority of the variable
region sequences, along with accessory genes and regulatory
sequences. The human variable region repertoire may be used to
generate antibody producing B-cells, which may be processed into
hybridomas by known techniques. A XenoMouse.RTM. immunized with a
target antigen will produce human antibodies by the normal immune
response, which may be harvested and/or produced by standard
techniques discussed above. A variety of strains of XenoMouse.RTM.
are available, each of which is capable of producing a different
class of antibody. Transgenically produced human antibodies have
been shown to have therapeutic potential, while retaining the
pharmacokinetic properties of normal human antibodies (Green et
al., 1999). The skilled artisan will realize that the claimed
compositions and methods are not limited to use of the
XenoMouse.RTM. system but may utilize any transgenic animal that
has been genetically engineered to produce human antibodies.
[0070] Known Antibodies and Target Antigens
[0071] As discussed above, in certain alternative embodiments the
anti-Trop-2 antibodies are of use for treating Trop-2-expressing
cancers, following detection of circulating Trop-2-positive tumor
cells. In some embodiments, the target cancer may express one or
more additional tumor-associated antigens (TAAs) that may be
targeted for tumor therapy. Particular antibodies that may be of
use for therapy of cancer include, but are not limited to, LL1
(anti-CD74), LL2 or RFB4 (anti-CD22), veltuzumab (hA20, anti-CD20),
rituxumab (anti-CD20), obinutuzumab (GA101, anti-CD20),
lambrolizumab (anti-PD-1 receptor), nivolumab (anti-PD-1 receptor),
ipilimumab (anti-CTLA-4), RS7 (anti-epithelial glycoprotein-1
(EGP-1, also known as Trop-2)), PAM4 or KC4 (both anti-mucin),
MN-14 (anti-carcinoembryonic antigen (CEA, also known as CD66e or
CEACAM5), MN-15 or MN-3 (anti-CEACAM6), Mu-9 (anti-colon-specific
antigen-p), Immu 31 (an anti-alpha-fetoprotein), R1 (anti-IGF-1R),
A19 (anti-CD19), TAG-72 (e.g., CC49), Tn, J591 or HuJ591 (anti-PSMA
(prostate-specific membrane antigen)), AB-PG1-XG1-026 (anti-PSMA
dimer), D2/B (anti-PSMA), G250 (an anti-carbonic anhydrase IX MAb),
L243 (anti-HLA-DR) alemtuzumab (anti-CD52), bevacizumab
(anti-VEGF), cetuximab (anti-EGFR), gemtuzumab (anti-CD33),
ibritumomab tiuxetan (anti-CD20); panitumumab (anti-EGFR);
tositumomab (anti-CD20); PAM4 (aka clivatuzumab, anti-mucin) and
trastuzumab (anti-ErbB2). Such antibodies are known in the art
(e.g., U.S. Pat. Nos. 5,686,072; 5,874,540; 6,107,090; 6,183,744;
6,306,393; 6,653,104; 6,730.300; 6,899,864; 6,926,893; 6,962,702;
7,074,403; 7,230,084; 7,238,785; 7,238,786; 7,256,004; 7,282,567;
7,300,655; 7,312,318; 7,585,491; 7,612,180; 7,642,239; and U.S.
Patent Application Publ. No. 20050271671; 20060193865; 20060210475;
20070087001; the Examples section of each incorporated herein by
reference.) Specific known antibodies of use include hPAM4 (U.S.
Pat. No. 7,282,567), hA20 (U.S. Pat. No. 7,251,164), hA19 (U.S.
Pat. No. 7,109,304), hIMMU-31 (U.S. Pat. No. 7,300,655), hLL1 (U.S.
Pat. No. 7,312,318), hLL2 (U.S. Pat. No. 7,074,403), hMu-9 (U.S.
Pat. No. 7,387,773), hL243 (U.S. Pat. No. 7,612,180), hMN-14 (U.S.
Pat. No. 6,676,924), hMN-15 (U.S. Pat. No. 7,541,440), hR1 (U.S.
patent application Ser. No. 12/772,645), hRS7 (U.S. Pat. No.
7,238,785), hMN-3 (U.S. Pat. No. 7,541,440), AB-PG1-XG1-026 (U.S.
patent application Ser. No. 11/983,372, deposited as ATCC PTA-4405
and PTA-4406) and D2/B (WO 2009/130575) the text of each recited
patent or application is incorporated herein by reference with
respect to the Figures and Examples sections.
[0072] Alternative antibodies of use include, but are not limited
to, abciximab (anti-glycoprotein IIb/IIIa), alemtuzumab
(anti-CD52), bevacizumab (anti-VEGF), cetuximab (anti-EGFR),
gemtuzumab (anti-CD33), ibritumomab (anti-CD20), panitumumab
(anti-EGFR), rituximab (anti-CD20), tositumomab (anti-CD20),
trastuzumab (anti-ErbB2), lambrolizumab (anti-PD-1 receptor),
nivolumab (anti-PD-1 receptor), ipilimumab (anti-CTLA-4),
abagovomab (anti-CA-125), adecatumumab (anti-EpCAM), atlizumab
(anti-IL-6 receptor), benralizumab (anti-CD125), obinutuzumab
(GA101, anti-CD20), CC49 (anti-TAG-72), AB-PG1-XG1-026 (anti-PSMA,
U.S. patent application Ser. No. 11/983,372, deposited as ATCC
PTA-4405 and PTA-4406), D2/B (anti-PSMA, WO 2009/130575),
tocilizumab (anti-IL-6 receptor), basiliximab (anti-CD25),
daclizumab (anti-CD25), efalizumab (anti-CD11a), GA101 (anti-CD20;
Glycart Roche), muromonab-CD3 (anti-CD3 receptor), natalizumab
(anti-.alpha.4 integrin), omalizumab (anti-IgE); anti-TNF-.alpha.
antibodies such as CDP571 (Ofei et al., 2011, Diabetes 45:881-85),
MTNFAI, M2TNFAI, M3TNFAI, M3TNFABI, M302B, M303 (Thermo Scientific,
Rockford, Ill.), infliximab (Centocor, Malvern, Pa.), certolizumab
pegol (UCB, Brussels, Belgium), anti-CD40L (UCB, Brussels,
Belgium), adalimumab (Abbott, Abbott Park, Ill.), and Benlysta
(Human Genome Sciences).
[0073] Other useful tumor-associated antigens that may be targeted
include carbonic anhydrase IX, B7, CCL19, CCL21, CSAp, HER-2/neu,
BrE3, CD1, CD1a, CD2, CD3, CD4, CD5, CD8, CD11A, CD14, CD15, CD16,
CD18, CD19, CD20 (e.g., C2B8, hA20, 1F5 MAbs), CD21, CD22, CD23,
CD25, CD29, CD30, CD32b, CD33, CD37, CD38, CD40, CD40L, CD44, CD45,
CD46, CD47, CD52, CD54, CD55, CD59, CD64, CD67, CD70, CD74, CD79a,
CD80, CD83, CD95, CD126, CD133, CD138, CD147, CD154, CEACAM5,
CEACAM6, CTLA-4, alpha-fetoprotein (AFP), VEGF (e.g., AVASTIN.RTM.,
fibronectin splice variant), ED-B fibronectin (e.g., L19), EGP-1
(Trop-2), EGP-2 (e.g., 17-1A), EGF receptor (ErbB1) (e.g.,
ERBITUX.RTM.), ErbB2, ErbB3, Factor H, FHL-1, Flt-3, folate
receptor, Ga 733, GRO-.beta., HMGB-1, hypoxia inducible factor
(HIF), HM1.24, HER-2/neu, histone H2B, histone H3, histone H4,
insulin-like growth factor (ILGF), IFN-.gamma., IFN-.alpha.,
IFN-.beta., IFN-.lamda., IL-2R, IL-4R, IL-6R, IL-13R, IL-15R,
IL-17R, IL-18R, IL-2, IL-6, IL-8, IL-12, IL-15, IL-17, IL-18,
IL-25, IP-10, IGF-1R, Ia, HM1.24, gangliosides, HCG, the HLA-DR
antigen to which L243 binds, CD66 antigens, i.e., CD66a-d or a
combination thereof, MAGE, mCRP, MCP-1, MIP-1A, MIP-1B, macrophage
migration-inhibitory factor (MIF), MUC1, MUC2, MUC3, MUC4, MUC5ac,
placental growth factor (P1GF), PSA (prostate-specific antigen),
PSMA, PAM4 antigen, PD-1 receptor, PD-L1, NCA-95, NCA-90, A3, A33,
Ep-CAM, KS-1, Le(y), mesothelin, S100, tenascin, TAC, Tn antigen,
Thomas-Friedenreich antigens, tumor necrosis antigens, tumor
angiogenesis antigens, TNF-.alpha., TRAIL receptor (R1 and R2),
Trop-2, VEGFR, RANTES, T101, as well as cancer stem cell antigens,
complement factors C3, C3a, C3b, C5a, C5, and an oncogene
product.
[0074] Cancer stem cells, which are ascribed to be more
therapy-resistant precursor malignant cell populations (Hill and
Perris, J. Natl. Cancer Inst. 2007; 99:1435-40), have antigens that
can be targeted in certain cancer types, such as CD133 in prostate
cancer (Maitland et al., Ernst Schering Found. Sympos. Proc. 2006;
5:155-79), non-small-cell lung cancer (Donnenberg et al., J.
Control Release 2007; 122(3):385-91), and glioblastoma (Beier et
al., Cancer Res. 2007; 67(9):4010-5), and CD44 in colorectal cancer
(Dalerba et al., Proc. Natl. Acad. Sci. USA 2007; 104(24)10158-63),
pancreatic cancer (Li et al., Cancer Res. 2007; 67(3):1030-7), and
in head and neck squamous cell carcinoma (Prince et al., Proc.
Natl. Acad. Sci. USA 2007; 104(3)973-8). Another useful target for
breast cancer therapy is the LIV-1 antigen described by Taylor et
al. (Biochem. J. 2003; 375:51-9).
[0075] Checkpoint-inhibitor antibodies have been used in cancer
therapy. Immune checkpoints refer to inhibitory pathways in the
immune system that are responsible for maintaining self-tolerance
and modulating the degree of immune system response to minimize
peripheral tissue damage. However, tumor cells can also activate
immune system checkpoints to decrease the effectiveness of immune
response against tumor tissues. Exemplary checkpoint inhibitor
antibodies against cytotoxic T-lymphocyte antigen 4 (CTLA4, also
known as CD152), programmed cell death protein 1 (PD1, also known
as CD279), programmed cell death 1 ligand 1 (PD-L1, also known as
CD274) and programmed cell death 1 ligand 2 (PD-L2) (Latchman et
al., 2001, Nat Immunol 2:261-8), may be used in combination with
one or more other agents to enhance the effectiveness of immune
response against disease cells, tissues or pathogens. Exemplary
anti-PD1 antibodies include lambrolizumab (MK-3475, MERCK),
nivolumab (BMS-936558, BRISTOL-MYERS SQUIBB), AMP-224 (MERCK), and
pidilizumab (CT-011, CURETECH LTD.). Anti-PD1 antibodies are
commercially available, for example from ABCAM.RTM. (AB137132),
BIOLEGEND.RTM. (EH12.2H7, RMP1-14) and AFFYMETRIX EBIOSCIENCE
(J105, J116, MIH4). Exemplary anti-PD-L1 antibodies include
MDX-1105 (MEDAREX), MEDI4736 (MEDIMMUNE) MPDL3280A (GENENTECH) and
BMS-936559 (BRISTOL-MYERS SQUIBB). Anti-PD-L1 antibodies are also
commercially available, for example from AFFYMETRIX EBIOSCIENCE
(MIH1). Exemplary anti-CTLA4 antibodies include ipilimumab
(Bristol-Myers Squibb) and tremelimumab (PFIZER). Anti-PD1
antibodies are commercially available, for example from ABCAM.RTM.
(AB134090), SINO BIOLOGICAL INC. (11159-H03H, 11159-H08H), and
THERMO SCIENTIFIC PIERCE (PA5-29572, PA5-23967, PA5-26465,
MA1-12205, MA1-35914). Ipilimumab has recently received FDA
approval for treatment of metastatic melanoma (Wada et al., 2013, J
Transl Med 11:89).
[0076] Macrophage migration inhibitory factor (MIF) is an important
regulator of innate and adaptive immunity and apoptosis. It has
been reported that CD74 is the endogenous receptor for MIF (Leng et
al., 2003, J Exp Med 197:1467-76). The therapeutic effect of
antagonistic anti-CD74 antibodies on MIF-mediated intracellular
pathways may be of use for treatment of a broad range of disease
states, such as cancers of the bladder, prostate, breast, lung, and
colon (e.g., Meyer-Siegler et al., 2004, BMC Cancer 12:34; Shachar
& Haran, 2011, Leuk Lymphoma 52:1446-54). Milatuzumab (hLL1) is
an exemplary anti-CD74 antibody of therapeutic use for treatment of
MIF-mediated diseases.
[0077] Various other antibodies of use are known in the art (e.g.,
U.S. Pat. Nos. 5,686,072; 5,874,540; 6,107,090; 6,183,744;
6,306,393; 6,653,104; 6,730.300; 6,899,864; 6,926,893; 6,962,702;
7,074,403; 7,230,084; 7,238,785; 7,238,786; 7,256,004; 7,282,567;
7,300,655; 7,312,318; 7,585,491; 7,612,180; 7,642,239 and U.S.
Patent Application Publ. No. 20060193865; each incorporated herein
by reference.)
[0078] Antibodies of use may be commercially obtained from a wide
variety of known sources. For example, a variety of antibody
secreting hybridoma lines are available from the American Type
Culture Collection (ATCC, Manassas, Va.). A large number of
antibodies against various disease targets, including
tumor-associated antigens, have been deposited at the ATCC and/or
have published variable region sequences and are available for use
in the claimed methods and compositions. See, e.g., U.S. Pat. Nos.
7,312,318; 7,282,567; 7,151,164; 7,074,403; 7,060,802; 7,056,509;
7,049,060; 7,045,132; 7,041,803; 7,041,802; 7,041,293; 7,038,018;
7,037,498; 7,012,133; 7,001,598; 6,998,468; 6,994,976; 6,994,852;
6,989,241; 6,974,863; 6,965,018; 6,964,854; 6,962,981; 6,962,813;
6,956,107; 6,951,924; 6,949,244; 6,946,129; 6,943,020; 6,939,547;
6,921,645; 6,921,645; 6,921,533; 6,919,433; 6,919,078; 6,916,475;
6,905,681; 6,899,879; 6,893,625; 6,887,468; 6,887,466; 6,884,594;
6,881,405; 6,878,812; 6,875,580; 6,872,568; 6,867,006; 6,864,062;
6,861,511; 6,861,227; 6,861,226; 6,838,282; 6,835,549; 6,835,370;
6,824,780; 6,824,778; 6,812,206; 6,793,924; 6,783,758; 6,770,450;
6,767,711; 6,764,688; 6,764,681; 6,764,679; 6,743,898; 6,733,981;
6,730,307; 6,720,155; 6,716,966; 6,709,653; 6,693,176; 6,692,908;
6,689,607; 6,689,362; 6,689,355; 6,682,737; 6,682,736; 6,682,734;
6,673,344; 6,653,104; 6,652,852; 6,635,482; 6,630,144; 6,610,833;
6,610,294; 6,605,441; 6,605,279; 6,596,852; 6,592,868; 6,576,745;
6,572;856; 6,566,076; 6,562,618; 6,545,130; 6,544,749; 6,534,058;
6,528,625; 6,528,269; 6,521,227; 6,518,404; 6,511,665; 6,491,915;
6,488,930; 6,482,598; 6,482,408; 6,479,247; 6,468,531; 6,468,529;
6,465,173; 6,461,823; 6,458,356; 6,455,044; 6,455,040; 6,451,310;
6,444,206; 6,441,143; 6,432,404; 6,432,402; 6,419,928; 6,413,726;
6,406,694; 6,403,770; 6,403,091; 6,395,276; 6,395,274; 6,387,350;
6,383,759; 6,383,484; 6,376,654; 6,372,215; 6,359,126; 6,355,481;
6,355,444; 6,355,245; 6,355,244; 6,346,246; 6,344,198; 6,340,571;
6,340,459; 6,331,175; 6,306,393; 6,254,868; 6,187,287; 6,183,744;
6,129,914; 6,120,767; 6,096,289; 6,077,499; 5,922,302; 5,874,540;
5,814,440; 5,798,229; 5,789,554; 5,776,456; 5,736,119; 5,716,595;
5,677,136; 5,587,459; 5,443,953; 5,525,338. These are exemplary
only and a wide variety of other antibodies and their hybridomas
are known in the art. The skilled artisan will realize that
antibody sequences or antibody-secreting hybridomas against almost
any disease-associated antigen may be obtained by a simple search
of the ATCC, NCBI and/or USPTO databases for antibodies against a
selected disease-associated target of interest. The antigen binding
domains of the cloned antibodies may be amplified, excised, ligated
into an expression vector, transfected into an adapted host cell
and used for protein production, using standard techniques well
known in the art.
[0079] Antibody Allotypes
[0080] Immunogenicity of therapeutic antibodies is associated with
increased risk of infusion reactions and decreased duration of
therapeutic response (Baert et al., 2003, N Engl J Med 348:602-08).
The extent to which therapeutic antibodies induce an immune
response in the host may be determined in part by the allotype of
the antibody (Stickler et al., 2011, Genes and Immunity 12:213-21).
Antibody allotype is related to amino acid sequence variations at
specific locations in the constant region sequences of the
antibody. The allotypes of IgG antibodies containing a heavy chain
.gamma.-type constant region are designated as Gm allotypes (1976,
J Immunol 117:1056-59).
[0081] For the common IgG1 human antibodies, the most prevalent
allotype is G1m1 (Stickler et al., 2011, Genes and Immunity
12:213-21). However, the G1m3 allotype also occurs frequently in
Caucasians (Stickler et al., 2011). It has been reported that G1m1
antibodies contain allotypic sequences that tend to induce an
immune response when administered to non-G1m1 (nG1m1) recipients,
such as G1m3 patients (Stickler et al., 2011). Non-G1m1 allotype
antibodies are not as immunogenic when administered to G1m1
patients (Stickler et al., 2011).
[0082] The human G1m1 allotype comprises the amino acids aspartic
acid at Kabat position 356 and leucine at Kabat position 358 in the
CH3 sequence of the heavy chain IgG1. The nG1m1 allotype comprises
the amino acids glutamic acid at Kabat position 356 and methionine
at Kabat position 358. Both G1m1 and nG1m1 allotypes comprise a
glutamic acid residue at Kabat position 357 and the allotypes are
sometimes referred to as DEL and EEM allotypes. A non-limiting
example of the heavy chain constant region sequences for G1m1 and
nG1m1 allotype antibodies is shown below for the exemplary
antibodies rituximab (SEQ ID NO:7) and veltuzumab (SEQ ID
NO:8).
TABLE-US-00001 Rituximab heavy chain constant region sequence (SEQ
ID NO: 7) ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV
HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKAEP
KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS
HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK
EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTC
LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW
QQGNVFSCSVMHEALHNHYTQKSLSLSPGK Veltuzumab heavy chain constant
region sequence (SEQ ID NO: 8)
ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV
HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEP
KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS
HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK
EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTC
LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW
QQGNVFSCSVMHEALHNHYTQKSLSLSPGK
[0083] Jefferis and Lefranc (2009, mAbs 1:1-7) reviewed sequence
variations characteristic of IgG allotypes and their effect on
immunogenicity. They reported that the G1m3 allotype is
characterized by an arginine residue at Kabat position 214,
compared to a lysine residue at Kabat 214 in the G1m17 allotype.
The nG1m1,2 allotype was characterized by glutamic acid at Kabat
position 356, methionine at Kabat position 358 and alanine at Kabat
position 431. The G1m1,2 allotype was characterized by aspartic
acid at Kabat position 356, leucine at Kabat position 358 and
glycine at Kabat position 431. In addition to heavy chain constant
region sequence variants, Jefferis and Lefranc (2009) reported
allotypic variants in the kappa light chain constant region, with
the Km1 allotype characterized by valine at Kabat position 153 and
leucine at Kabat position 191, the Km1,2 allotype by alanine at
Kabat position 153 and leucine at Kabat position 191, and the Km3
allotype characterized by alanine at Kabat position 153 and valine
at Kabat position 191.
[0084] With regard to therapeutic antibodies, veltuzumab and
rituximab are, respectively, humanized and chimeric IgG1 antibodies
against CD20, of use for therapy of a wide variety of hematological
malignancies and/or autoimmune diseases. Table 1 compares the
allotype sequences of rituximab vs. veltuzumab. As shown in Table
1, rituximab (G1m17,1) is a DEL allotype IgG1, with an additional
sequence variation at Kabat position 214 (heavy chain CH1) of
lysine in rituximab vs. arginine in veltuzumab. It has been
reported that veltuzumab is less immunogenic in subjects than
rituximab (see, e.g., Morchhauser et al., 2009, J Clin Oncol
27:3346-53; Goldenberg et al., 2009, Blood 113:1062-70; Robak &
Robak, 2011, BioDrugs 25:13-25), an effect that has been attributed
to the difference between humanized and chimeric antibodies.
However, the difference in allotypes between the EEM and DEL
allotypes likely also accounts for the lower immunogenicity of
veltuzumab.
TABLE-US-00002 TABLE 1 Allotypes of Rituximab vs. Veltuzumab Heavy
chain position and associated allotypes Complete 214 356/358 431
allotype (allotype) (allotype) (allotype) Rituximab G1m17,1 K 17
D/L 1 A -- Veltuzumab G1m3 R 3 E/M -- A --
[0085] In order to reduce the immunogenicity of therapeutic
antibodies in individuals of nG1m1 genotype, it is desirable to
select the allotype of the antibody to correspond to the G1m3
allotype, characterized by arginine at Kabat 214, and the nG1m1,2
null-allotype, characterized by glutamic acid at Kabat position
356, methionine at Kabat position 358 and alanine at Kabat position
431. Surprisingly, it was found that repeated subcutaneous
administration of G1m3 antibodies over a long period of time did
not result in a significant immune response. In alternative
embodiments, the human IgG4 heavy chain in common with the G1m3
allotype has arginine at Kabat 214, glutamic acid at Kabat 356,
methionine at Kabat 359 and alanine at Kabat 431. Since
immunogenicity appears to relate at least in part to the residues
at those locations, use of the human IgG4 heavy chain constant
region sequence for therapeutic antibodies is also a preferred
embodiment. Combinations of G1m3 IgG1 antibodies with IgG4
antibodies may also be of use for therapeutic administration.
Nanobodies
[0086] Nanobodies are single-domain antibodies of about 12-15 kDa
in size (about 110 amino acids in length). Nanobodies can
selectively bind to target antigens, like full-size antibodies, and
have similar affinities for antigens. However, because of their
much smaller size, they may be capable of better penetration into
solid tumors. The smaller size also contributes to the stability of
the nanobody, which is more resistant to pH and temperature
extremes than full size antibodies (Van Der Linden et al., 1999,
Biochim Biophys Act 1431:37-46). Single-domain antibodies were
originally developed following the discovery that camelids (camels,
alpacas, llamas) possess fully functional antibodies without light
chains (e.g., Hamsen et al., 2007, Appl Microbiol Biotechnol
77:13-22). The heavy-chain antibodies consist of a single variable
domain (V.sub.HH) and two constant domains (C.sub.H2 and C.sub.H3).
Like antibodies, nanobodies may be developed and used as
multivalent and/or bispecific constructs. Humanized forms of
nanobodies are in commercial development that are targeted to a
variety of target antigens, such as IL-6R, vWF, TNF, RSV, RANKL,
IL-17A & F and IgE (e.g., ABLYNX.RTM., Ghent, Belgium), with
potential clinical use in cancer and other disorders (e.g., Saerens
et al., 2008, Curr Opin Pharmacol 8:600-8; Muyldermans, 2013, Ann
Rev Biochem 82:775-97; Ibanez et al., 2011, J Infect Dis
203:1063-72).
[0087] The plasma half-life of nanobodies is shorter than that of
full-size antibodies, with elimination primarily by the renal
route. Because they lack an Fc region, they do not exhibit
complement dependent cytotoxicity.
[0088] Nanobodies may be produced by immunization of camels,
llamas, alpacas or sharks with target antigen, following by
isolation of mRNA, cloning into libraries and screening for antigen
binding. Nanobody sequences may be humanized by standard techniques
(e.g., Jones et al., 1986, Nature 321: 522, Riechmann et al., 1988,
Nature 332: 323, Verhoeyen et al., 1988, Science 239: 1534, Carter
et al., 1992, Proc. Nat'l Acad. Sci. USA 89: 4285, Sandhu, 1992,
Crit. Rev. Biotech. 12: 437, Singer et al., 1993, J. Immun. 150:
2844). Humanization is relatively straight-forward because of the
high homology between camelid and human FR sequences.
[0089] In various embodiments, the subject antibodies may comprise
nanobodies for targeted delivery of conjugated diagnostic agent(s)
to targeted cancer cells. Nanobodies of use are disclosed, for
example, in U.S. Pat. Nos. 7,807,162; 7,939,277; 8,188,223;
8,217,140; 8,372,398; 8,557,965; 8,623,361 and 8,629,244, the
Examples section of each incorporated herein by reference.)
[0090] Antibody Fragments
[0091] Antibody fragments are antigen binding portions of an
antibody, such as F(ab').sub.2, Fab', F(ab).sub.2, Fab, Fv, sFv,
scFv and the like. Antibody fragments which recognize specific
epitopes can be generated by known techniques. F(ab').sub.2
fragments, for example, can be produced by pepsin digestion of the
antibody molecule. These and other methods are described, for
example, by Goldenberg, U.S. Pat. Nos. 4,036,945 and 4,331,647 and
references contained therein. Also, see Nisonoff et al., Arch
Biochem. Biophys. 89: 230 (1960); Porter, Biochem. J. 73: 119
(1959), Edelman et al., in METHODS IN ENZYMOLOGY VOL. 1, page 422
(Academic Press 1967), and Coligan at pages 2.8.1-2.8.10 and
2.10.-2.10.4. Alternatively, Fab' expression libraries can be
constructed (Huse et al., 1989, Science, 246:1274-1281) to allow
rapid and easy identification of monoclonal Fab' fragments with the
desired specificity.
[0092] A single chain Fv molecule (scFv) comprises a VL domain and
a VH domain. The VL and VH domains associate to form a target
binding site. These two domains are further covalently linked by a
peptide linker (L). A scFv molecule is denoted as either VL-L-VH if
the VL domain is the N-terminal part of the scFv molecule, or as
VH-L-VL if the VH domain is the N-terminal part of the scFv
molecule. Methods for making scFv molecules and designing suitable
peptide linkers are described in U.S. Pat. Nos. 4,704,692,
4,946,778, R. Raag and M. Whitlow, "Single Chain Fvs." FASEB Vol
9:73-80 (1995) and R. E. Bird and B. W. Walker, Single Chain
Antibody Variable Regions, TIBTECH, Vol 9: 132-137 (1991).
[0093] Other antibody fragments, for example single domain antibody
fragments, are known in the art and may be used in the claimed
constructs. Single domain antibodies (VHH) may be obtained, for
example, from camels, alpacas or llamas by standard immunization
techniques. (See, e.g., Muyldermans et al., TIBS 26:230-235, 2001;
Yau et al., J Immunol Methods 281:161-75, 2003; Maass et al., J
Immunol Methods 324:13-25, 2007). The VHH may have potent
antigen-binding capacity and can interact with novel epitopes that
are inaccessible to conventional VH-VL pairs. (Muyldermans et al.,
2001). Alpaca serum IgG contains about 50% camelid heavy chain only
IgG antibodies (HCAbs) (Maass et al., 2007). Alpacas may be
immunized with known antigens, such as TNF-.alpha., and VHHs can be
isolated that bind to and neutralize the target antigen (Maass et
al., 2007). PCR primers that amplify virtually all alpaca VHH
coding sequences have been identified and may be used to construct
alpaca VHH phage display libraries, which can be used for antibody
fragment isolation by standard biopanning techniques well known in
the art (Maass et al., 2007).
[0094] An antibody fragment can also be prepared by proteolytic
hydrolysis of a full-length antibody or by expression in E. coli or
another host of the DNA coding for the fragment. An antibody
fragment can be obtained by pepsin or papain digestion of
full-length antibodies by conventional methods. For example, an
antibody fragment can be produced by enzymatic cleavage of
antibodies with pepsin to provide an approximate 100 kD fragment
denoted F(ab').sub.2. This fragment can be further cleaved using a
thiol reducing agent, and optionally a blocking group for the
sulfhydryl groups resulting from cleavage of disulfide linkages, to
produce an approximate 50 Kd Fab' monovalent fragment.
Alternatively, an enzymatic cleavage using papain produces two
monovalent Fab fragments and an Fc fragment directly.
[0095] Other methods of cleaving antibodies, such as separation of
heavy chains to form monovalent light-heavy chain fragments,
further cleavage of fragments, or other enzymatic, chemical or
genetic techniques may also be used, so long as the fragments bind
to the antigen that is recognized by the intact antibody.
[0096] General Techniques for Antibody Cloning and Production
[0097] Various techniques, such as production of chimeric or
humanized antibodies, may involve procedures of antibody cloning
and construction. The antigen-binding V.kappa. (variable light
chain) and V.sub.H (variable heavy chain) sequences for an antibody
of interest may be obtained by a variety of molecular cloning
procedures, such as RT-PCR, 5'-RACE, and cDNA library screening.
The V genes of a MAb from a cell that expresses a murine MAb can be
cloned by PCR amplification and sequenced. To confirm their
authenticity, the cloned V.sub.L and V.sub.H genes can be expressed
in cell culture as a chimeric Ab as described by Orlandi et al.,
(Proc. Natl. Acad. Sci., USA, 86: 3833 (1989)). Based on the V gene
sequences, a humanized MAb can then be designed and constructed as
described by Leung et al. (Mol. Immunol., 32: 1413 (1995)).
[0098] cDNA can be prepared from any known hybridoma line or
transfected cell line producing a murine MAb by general molecular
cloning techniques (Sambrook et al., Molecular Cloning, A
laboratory manual, 2.sup.nd Ed (1989)). The V.kappa. sequence for
the MAb may be amplified using the primers VK1BACK and VK1FOR
(Orlandi et al., 1989) or the extended primer set described by
Leung et al. (BioTechniques, 15: 286 (1993)). The V.sub.H sequences
can be amplified using the primer pair VH1BACK/VH1FOR (Orlandi et
al., 1989) or the primers annealing to the constant region of
murine IgG described by Leung et al. (Hybridoma, 13:469 (1994)).
Humanized V genes can be constructed by a combination of long
oligonucleotide template syntheses and PCR amplification as
described by Leung et al. (Mol. Immunol., 32: 1413 (1995)).
[0099] PCR products for V.kappa. can be subcloned into a staging
vector, such as a pBR327-based staging vector, VKpBR, that contains
an Ig promoter, a signal peptide sequence and convenient
restriction sites. PCR products for V.sub.H can be subcloned into a
similar staging vector, such as the pBluescript-based VHpBS.
Expression cassettes containing the V.kappa. and V.sub.H sequences
together with the promoter and signal peptide sequences can be
excised from VKpBR and VHpBS and ligated into appropriate
expression vectors, such as pKh and pG1g, respectively (Leung et
al., Hybridoma, 13:469 (1994)). The expression vectors can be
co-transfected into an appropriate cell and supernatant fluids
monitored for production of a chimeric, humanized or human MAb.
Alternatively, the V.kappa. and V.sub.H expression cassettes can be
excised and subcloned into a single expression vector, such as
pdHL2, as described by Gillies et al. (J. Immunol. Methods 125:191
(1989) and also shown in Losman et al., Cancer, 80:2660
(1997)).
[0100] In an alternative embodiment, expression vectors may be
transfected into host cells that have been pre-adapted for
transfection, growth and expression in serum-free medium. Exemplary
cell lines that may be used include the Sp/EEE, Sp/ESF and Sp/ESF-X
cell lines (see, e.g., U.S. Pat. Nos. 7,531,327; 7,537,930 and
7,608,425; the Examples section of each of which is incorporated
herein by reference). These exemplary cell lines are based on the
Sp2/0 myeloma cell line, transfected with a mutant Bcl-EEE gene,
exposed to methotrexate to amplify transfected gene sequences and
pre-adapted to serum-free cell line for protein expression.
[0101] Bispecific and Multispecific Antibodies
[0102] In certain alternative embodiments, the anti-Trop-2 antibody
or fragment thereof may be co-administered with, for example, a
hapten-binding antibody or fragment thereof, such as an anti-HSG or
anti-In-DTPA antibody. Such bispecific antibodies may be of use in
pretargeting techniques for administration of diagnostic and/or
therapeutic agents to Trop-2 positive tumors in vivo. In other
embodiments, bispecific or multispecific antibodies may be utilized
directly for anti-cancer therapy.
[0103] Numerous methods to produce bispecific or multispecific
antibodies are known, as disclosed, for example, in U.S. Pat. No.
7,405,320, the Examples section of which is incorporated herein by
reference. Bispecific antibodies can be produced by the quadroma
method, which involves the fusion of two different hybridomas, each
producing a monoclonal antibody recognizing a different antigenic
site (Milstein and Cuello, Nature, 1983; 305:537-540).
[0104] Another method for producing bispecific antibodies uses
heterobifunctional cross-linkers to chemically tether two different
monoclonal antibodies (Staerz, et al. Nature. 1985; 314:628-631;
Perez, et al. Nature. 1985; 316:354-356). Bispecific antibodies can
also be produced by reduction of each of two parental monoclonal
antibodies to the respective half molecules, which are then mixed
and allowed to reoxidize to obtain the hybrid structure (Staerz and
Bevan. Proc Natl Acad Sci USA. 1986; 83:1453-1457). Other methods
include improving the efficiency of generating hybrid hybridomas by
gene transfer of distinct selectable markers via retrovirus-derived
shuttle vectors into respective parental hybridomas, which are
fused subsequently (DeMonte, et al. Proc Natl Acad Sci USA. 1990,
87:2941-2945); or transfection of a hybridoma cell line with
expression plasmids containing the heavy and light chain genes of a
different antibody.
[0105] Cognate V.sub.H and V.sub.L domains can be joined with a
peptide linker of appropriate composition and length (usually
consisting of more than 12 amino acid residues) to form a
single-chain Fv (scFv), as discussed above. Reduction of the
peptide linker length to less than 12 amino acid residues prevents
pairing of V.sub.H and V.sub.L domains on the same chain and forces
pairing of V.sub.H and V.sub.L domains with complementary domains
on other chains, resulting in the formation of functional
multimers. Polypeptide chains of V.sub.H and V.sub.L domains that
are joined with linkers between 3 and 12 amino acid residues form
predominantly dimers (termed diabodies). With linkers between 0 and
2 amino acid residues, trimers (termed triabody) and tetramers
(termed tetrabody) are favored, but the exact patterns of
oligomerization appear to depend on the composition as well as the
orientation of V-domains (V.sub.H-linker-V.sub.L or
V.sub.L-linker-V.sub.H), in addition to the linker length.
[0106] These techniques for producing multispecific or bispecific
antibodies exhibit various difficulties in terms of low yield,
necessity for purification, low stability or the
labor-intensiveness of the technique. More recently, a technique
known as "DOCK-AND-LOCK.RTM." (DNL.RTM.), discussed in more detail
below, has been utilized to produce combinations of virtually any
desired antibodies, antibody fragments and other effector
molecules. Any of the techniques known in the art for making
bispecific or multispecific antibodies may be utilized in the
practice of the presently claimed methods.
[0107] DOCK-AND-LOCK.RTM. (DNL.RTM.)
[0108] Bispecific or multispecific antibodies or other constructs
may be produced using the DOCK-AND-LOCK.RTM. technology (see, e.g.,
U.S. Pat. Nos. 7,550,143; 7,521,056; 7,534,866; 7,527,787 and
7,666,400, the Examples section of each incorporated herein by
reference). Generally, the technique takes advantage of the
specific and high-affinity binding interactions that occur between
a dimerization and docking domain (DDD) sequence of the regulatory
(R) subunits of cAMP-dependent protein kinase (PKA) and an anchor
domain (AD) sequence derived from any of a variety of AKAP proteins
(Baillie et al., FEBS Letters. 2005; 579: 3264. Wong and Scott,
Nat. Rev. Mol. Cell Biol. 2004; 5: 959). The DDD and AD peptides
may be attached to any protein, peptide or other molecule,
preferably as a fusion protein comprising the AD or DDD sequence.
Because the DDD sequences spontaneously dimerize and bind to the AD
sequence, the technique allows the formation of complexes between
any selected molecules that may be attached to DDD or AD
sequences.
[0109] Although the standard DNL.RTM. complex comprises a trimer
with two DDD-linked molecules attached to one AD-linked molecule,
variations in complex structure allow the formation of dimers,
trimers, tetramers, pentamers, hexamers and other multimers. In
some embodiments, the DNL.RTM. complex may comprise two or more
antibodies, antibody fragments or fusion proteins which bind to the
same antigenic determinant or to two or more different antigens.
The DNL.RTM. complex may also comprise one or more other effectors,
such as proteins, peptides, immunomodulators, cytokines,
interleukins, interferons, binding proteins, peptide ligands,
carrier proteins, toxins, ribonucleases such as onconase,
inhibitory oligonucleotides such as siRNA, antigens or
xenoantigens, polymers such as PEG, enzymes, therapeutic agents,
hormones, cytotoxic agents, anti-angiogenic agents, pro-apoptotic
agents or any other molecule or aggregate.
[0110] PKA, which plays a central role in one of the best studied
signal transduction pathways triggered by the binding of the second
messenger cAMP to the R subunits, was first isolated from rabbit
skeletal muscle in 1968 (Walsh et al., J. Biol. Chem. 1968;
243:3763). The structure of the holoenzyme consists of two
catalytic subunits held in an inactive form by the R subunits
(Taylor, J. Biol. Chem. 1989; 264:8443). Isozymes of PKA are found
with two types of R subunits (RI and RII), and each type has
.alpha. and .beta. isoforms (Scott, Pharmacol. Ther. 1991; 50:123).
Thus, the four isoforms of PKA regulatory subunits are RI.alpha.,
RI.beta., RII.alpha. and RII.beta.. The R subunits have been
isolated only as stable dimers and the dimerization domain has been
shown to consist of the first 44 amino-terminal residues of
RII.alpha. (Newlon et al., Nat. Struct. Biol. 1999; 6:222). As
discussed below, similar portions of the amino acid sequences of
other regulatory subunits are involved in dimerization and docking,
each located near the N-terminal end of the regulatory subunit.
Binding of cAMP to the R subunits leads to the release of active
catalytic subunits for a broad spectrum of serine/threonine kinase
activities, which are oriented toward selected substrates through
the compartmentalization of PKA via its docking with AKAPs (Scott
et al., J. Biol. Chem. 1990; 265;21561)
[0111] Since the first AKAP, microtubule-associated protein-2, was
characterized in 1984 (Lohmann et al., Proc. Natl. Acad. Sci USA.
1984; 81:6723), more than 50 AKAPs that localize to various
sub-cellular sites, including plasma membrane, actin cytoskeleton,
nucleus, mitochondria, and endoplasmic reticulum, have been
identified with diverse structures in species ranging from yeast to
humans (Wong and Scott, Nat. Rev. Mol. Cell Biol. 2004; 5:959). The
AD of AKAPs for PKA is an amphipathic helix of 14-18 residues (Carr
et al., J. Biol. Chem. 1991; 266:14188). The amino acid sequences
of the AD are quite varied among individual AKAPs, with the binding
affinities reported for RII dimers ranging from 2 to 90 nM (Alto et
al., Proc. Natl. Acad. Sci. USA. 2003; 100:4445). AKAPs will only
bind to dimeric R subunits. For human RII.alpha., the AD binds to a
hydrophobic surface formed by the 23 amino-terminal residues
(Colledge and Scott, Trends Cell Biol. 1999; 6:216). Thus, the
dimerization domain and AKAP binding domain of human RII.alpha. are
both located within the same N-terminal 44 amino acid sequence
(Newlon et al., Nat. Struct. Biol. 1999; 6:222; Newlon et al., EMBO
J. 2001; 20:1651), which is termed the DDD herein.
[0112] We have developed a platform technology to utilize the DDD
of human PKA regulatory subunits and the AD of AKAP as an excellent
pair of linker modules for docking any two entities, referred to
hereafter as A and B, into a noncovalent complex, which could be
further locked into a DNL.RTM. complex through the introduction of
cysteine residues into both the DDD and AD at strategic positions
to facilitate the formation of disulfide bonds. The general
methodology of the approach is as follows. Entity A is constructed
by linking a DDD sequence to a precursor of A, resulting in a first
component hereafter referred to as a. Because the DDD sequence
would effect the spontaneous formation of a dimer, A would thus be
composed of a.sub.2. Entity B is constructed by linking an AD
sequence to a precursor of B, resulting in a second component
hereafter referred to as b. The dimeric motif of DDD contained in
a.sub.2 will create a docking site for binding to the AD sequence
contained in b, thus facilitating a ready association of a.sub.2
and b to form a binary, trimeric complex composed of a.sub.2b. This
binding event is made irreversible with a subsequent reaction to
covalently secure the two entities via disulfide bridges, which
occurs very efficiently based on the principle of effective local
concentration because the initial binding interactions should bring
the reactive thiol groups placed onto both the DDD and AD into
proximity (Chmura et al., Proc. Natl. Acad. Sci. USA. 2001;
98:8480) to ligate site-specifically. Using various combinations of
linkers, adaptor modules and precursors, a wide variety of DNL.RTM.
constructs of different stoichiometry may be produced and used
(see, e.g., U.S. Pat. Nos. 7,550,143; 7,521,056; 7,534,866;
7,527,787 and 7,666,400.)
[0113] By attaching the DDD and AD away from the functional groups
of the two precursors, such site-specific ligations are also
expected to preserve the original activities of the two precursors.
This approach is modular in nature and potentially can be applied
to link, site-specifically and covalently, a wide range of
substances, including peptides, proteins, antibodies, antibody
fragments, and other effector moieties with a wide range of
activities. Utilizing the fusion protein method of constructing AD
and DDD conjugated effectors described below, virtually any protein
or peptide may be incorporated into a DNL.RTM. construct. However,
the technique is not limiting and other methods of conjugation may
be utilized.
[0114] A variety of methods are known for making fusion proteins,
including nucleic acid synthesis, hybridization and/or
amplification to produce a synthetic double-stranded nucleic acid
encoding a fusion protein of interest. Such double-stranded nucleic
acids may be inserted into expression vectors for fusion protein
production by standard molecular biology techniques (see, e.g.
Sambrook et al., Molecular Cloning, A laboratory manual, 2.sup.nd
Ed, 1989). In such preferred embodiments, the AD and/or DDD moiety
may be attached to either the N-terminal or C-terminal end of an
effector protein or peptide. However, the skilled artisan will
realize that the site of attachment of an AD or DDD moiety to an
effector moiety may vary, depending on the chemical nature of the
effector moiety and the part(s) of the effector moiety involved in
its physiological activity. Site-specific attachment of a variety
of effector moieties may be performed using techniques known in the
art, such as the use of bivalent cross-linking reagents and/or
other chemical conjugation techniques.
[0115] Structure-Function Relationships in AD and DDD Moieties
[0116] For different types of DNL.RTM. constructs, different AD or
DDD sequences may be utilized. Exemplary DDD and AD sequences are
provided below.
TABLE-US-00003 DDD1 (SEQ ID NO: 9)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA DDD2 (SEQ ID NO: 10)
CGHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA AD1 (SEQ ID NO: 11)
QIEYLAKQIVDNAIQQA AD2 (SEQ ID NO: 12) CGQIEYLAKQIVDNAIQQAGC
[0117] The skilled artisan will realize that DDD1 and DDD2 are
based on the DDD sequence of the human RII.alpha. isoform of
protein kinase A. However, in alternative embodiments, the DDD and
AD moieties may be based on the DDD sequence of the human RI.alpha.
form of protein kinase A and a corresponding AKAP sequence, as
exemplified in DDD3, DDD3C and AD3 below.
TABLE-US-00004 DDD3 (SEQ ID NO: 13)
SLRECELYVQKHNIQALLKDSIVQLCTARPERPMAFLREYFERLEKEEAK DDD3C (SEQ ID
NO: 14) MSCGGSLRECELYVQKHNIQALLKDSIVQLCTARPERPMAFLREYFERLE KEEAK
AD3 (SEQ ID NO: 15) CGFEELAWKIAKMIWSDVFQQGC
[0118] In other alternative embodiments, other sequence variants of
AD and/or DDD moieties may be utilized in construction of the
DNL.RTM. complexes. For example, there are only four variants of
human PKA DDD sequences, corresponding to the DDD moieties of PKA
RI.alpha., RII.alpha., RI.beta. and RII.beta.. The RII.alpha. DDD
sequence is the basis of DDD1 and DDD2 disclosed above. The four
human PKA DDD sequences are shown below. The DDD sequence
represents residues 1-44 of RII.alpha., 1-44 of RII.beta., 12-61 of
RI.alpha. and 13-66 of RI.beta.. (Note that the sequence of DDD1 is
modified slightly from the human PKA RII.alpha. DDD moiety.)
TABLE-US-00005 PKA RI.alpha. (SEQ ID NO: 16)
SLRECELYVQKHNIQALLKDVSIVQLCTARPERPMAFLREYFEKLEKEE AK PKA RI.beta.
(SEQ ID NO: 17) SLKGCELYVQLHGIQQVLKDCIVHLCISKPERPMKFLREHFEKLEKEENR
QILA PKA RII.alpha. (SEQ ID NO: 18)
SHIQIPPGLTELLQGYTVEVGQQPPDLVDFAVEYFTRLREARRQ PKA RII.beta. (SEQ ID
NO: 19) SIEIPAGLTELLQGFTVEVLRHQPADLLEFALQHFTRLQQENER
[0119] The structure-function relationships of the AD and DDD
domains have been the subject of investigation. (See, e.g.,
Burns-Hamuro et al., 2005, Protein Sci 14:2982-92; Carr et al.,
2001, J Biol Chem 276:17332-38; Alto et al., 2003, Proc Natl Acad
Sci USA 100:4445-50; Hundsrucker et al., 2006, Biochem J
396:297-306; Stokka et al., 2006, Biochem J 400:493-99; Gold et
al., 2006, Mol Cell 24:383-95; Kinderman et al., 2006, Mol Cell
24:397-408, the entire text of each of which is incorporated herein
by reference.)
[0120] For example, Kinderman et al. (2006, Mol Cell 24:397-408)
examined the crystal structure of the AD-DDD binding interaction
and concluded that the human DDD sequence contained a number of
conserved amino acid residues that were important in either dimer
formation or AKAP binding, underlined in SEQ ID NO:9 below. (See
FIG. 1 of Kinderman et al., 2006, incorporated herein by
reference.) The skilled artisan will realize that in designing
sequence variants of the DDD sequence, one would desirably avoid
changing any of the underlined residues, while conservative amino
acid substitutions might be made for residues that are less
critical for dimerization and AKAP binding.
TABLE-US-00006 (SEQ ID NO: 9)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA
[0121] As discussed in more detail below, conservative amino acid
substitutions have been characterized for each of the twenty common
L-amino acids. Thus, based on the data of Kinderman (2006) and
conservative amino acid substitutions, potential alternative DDD
sequences based on SEQ ID NO:9 are shown in Table 2. In devising
Table 2, only highly conservative amino acid substitutions were
considered. For example, charged residues were only substituted for
residues of the same charge, residues with small side chains were
substituted with residues of similar size, hydroxyl side chains
were only substituted with other hydroxyls, etc. Because of the
unique effect of proline on amino acid secondary structure, no
other residues were substituted for proline. A limited number of
such potential alternative DDD moiety sequences are shown in SEQ ID
NO:20 to SEQ ID NO:39 below. The skilled artisan will realize that
an almost unlimited number of alternative species within the genus
of DDD moieties can be constructed by standard techniques, for
example using a commercial peptide synthesizer or well known
site-directed mutagenesis techniques. The effect of the amino acid
substitutions on AD moiety binding may also be readily determined
by standard binding assays, for example as disclosed in Alto et al.
(2003, Proc Natl Acad Sci USA 100:4445-50).
TABLE-US-00007 TABLE 2 Conservative Amino Acid Substitutions in
DDD1 (SEQ ID NO: 9). Consensus sequence disclosed as SEQ ID NO: 94.
S H I Q I P P G L T E L L Q G Y T V E V L R T K N A S D N A S D K R
Q Q P P D L V E F A V E Y F T R L R E A R A N N E D L D S K K D L K
L I I I V V V THIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID
NO: 20) SKIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO:
21) SRIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 22)
SHINIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 23)
SHIQIPPALTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 24)
SHIQIPPGLSELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 25)
SHIQIPPGLTDLLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 26)
SHIQIPPGLTELLNGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 27)
SHIQIPPGLTELLQAYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 28)
SHIQIPPGLTELLQGYSVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 29)
SHIQIPPGLTELLQGYTVDVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 30)
SHIQIPPGLTELLQGYTVEVLKQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 31)
SHIQIPPGLTELLQGYTVEVLRNQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 32)
SHIQIPPGLTELLQGYTVEVLRQNPPDLVEFAVEYFTRLREARA (SEQ ID NO: 33)
SHIQIPPGLTELLQGYTVEVLRQQPPELVEFAVEYFTRLREARA (SEQ ID NO: 34)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVDFAVEYFTRLREARA (SEQ ID NO: 35)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFLVEYFTRLREARA (SEQ ID NO: 36)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFIVEYFTRLREARA (SEQ ID NO: 37)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFVVEYFTRLREARA (SEQ ID NO: 38)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVDYFTRLREARA (SEQ ID NO: 39)
[0122] Alto et al. (2003, Proc Natl Acad Sci USA 100:4445-50)
performed a bioinformatic analysis of the AD sequence of various
AKAP proteins to design an RII selective AD sequence called AKAP-IS
(SEQ ID NO:11), with a binding constant for DDD of 0.4 nM. The
AKAP-IS sequence was designed as a peptide antagonist of AKAP
binding to PKA. Residues in the AKAP-IS sequence where
substitutions tended to decrease binding to DDD are underlined in
SEQ ID NO:11 below. The skilled artisan will realize that in
designing sequence variants of the AD sequence, one would desirably
avoid changing any of the underlined residues, while conservative
amino acid substitutions might be made for residues that are less
critical for DDD binding. Table 3 shows potential conservative
amino acid substitutions in the sequence of AKAP-IS (AD1, SEQ ID
NO:19), similar to that shown for DDD1 (SEQ ID NO:16) in Table 2
above.
[0123] A limited number of such potential alternative AD moiety
sequences are shown in SEQ ID NO:40 to SEQ ID NO:57 below. Again, a
very large number of species within the genus of possible AD moiety
sequences could be made, tested and used by the skilled artisan,
based on the data of Alto et al. (2003). It is noted that FIG. 2 of
Alto (2003) shows an even large number of potential amino acid
substitutions that may be made, while retaining binding activity to
DDD moieties, based on actual binding experiments.
TABLE-US-00008 AKAP-IS (SEQ ID NO: 11) QIEYLAKQIVDNAIQQA
TABLE-US-00009 TABLE 3 Conservative Amino Acid Substitutions in AD1
(SEQ ID NO: 11). Consensus sequence disclosed as SEQ ID NO: 95. Q I
E Y L A K Q I V D N A I Q Q A N L D F I R N E Q N N L V T V I S V
NIEYLAKQIVDNAIQQA (SEQ ID NO: 40) QLEYLAKQIVDNAIQQA (SEQ ID NO: 41)
QVEYLAKQIVDNAIQQA (SEQ ID NO: 42) QIDYLAKQIVDNAIQQA (SEQ ID NO: 43)
QIEFLAKQIVDNAIQQA (SEQ ID NO: 44) QIETLAKQIVDNAIQQA (SEQ ID NO: 45)
QIESLAKQIVDNAIQQA (SEQ ID NO: 46) QIEYIAKQIVDNAIQQA (SEQ ID NO: 47)
QIEYVAKQIVDNAIQQA (SEQ ID NO: 48) QIEYLARQIVDNAIQQA (SEQ ID NO: 49)
QIEYLAKNIVDNAIQQA (SEQ ID NO: 50) QIEYLAKQIVENAIQQA (SEQ ID NO: 51)
QIEYLAKQIVDQAIQQA (SEQ ID NO: 52) QIEYLAKQIVDNAINQA (SEQ ID NO: 53)
QIEYLAKQIVDNAIQNA (SEQ ID NO: 54) QIEYLAKQIVDNAIQQL (SEQ ID NO: 55)
QIEYLAKQIVDNAIQQI (SEQ ID NO: 56) QIEYLAKQIVDNAIQQV (SEQ ID NO:
57)
[0124] Gold et al. (2006, Mol Cell 24:383-95) utilized
crystallography and peptide screening to develop a SuperAKAP-IS
sequence (SEQ ID NO:58), exhibiting a five order of magnitude
higher selectivity for the RII isoform of PKA compared with the RI
isoform. Underlined residues indicate the positions of amino acid
substitutions, relative to the AKAP-IS sequence, which increased
binding to the DDD moiety of RII.alpha.. In this sequence, the
N-terminal Q residue is numbered as residue number 4 and the
C-terminal A residue is residue number 20. Residues where
substitutions could be made to affect the affinity for RII.alpha.
were residues 8, 11, 15, 16, 18, 19 and 20 (Gold et al., 2006). It
is contemplated that in certain alternative embodiments, the
SuperAKAP-IS sequence may be substituted for the AKAP-IS AD moiety
sequence to prepare DNL.RTM. constructs. Other alternative
sequences that might be substituted for the AKAP-IS AD sequence are
shown in SEQ ID NO:59-61. Substitutions relative to the AKAP-IS
sequence are underlined. It is anticipated that, as with the AD2
sequence shown in SEQ ID NO:12, the AD moiety may also include the
additional N-terminal residues cysteine and glycine and C-terminal
residues glycine and cysteine.
TABLE-US-00010 SuperAKAP-IS (SEQ ID NO: 58) QIEYVAKQIVDYAIHQA
Alternative AKAP sequences (SEQ ID NO: 59) QIEYKAKQIVDHAIHQA (SEQ
ID NO: 60) QIEYHAKQIVDHAIHQA (SEQ ID NO: 61) QIEYVAKQIVDHAIHQA
[0125] FIG. 2 of Gold et al. disclosed additional DDD-binding
sequences from a variety of AKAP proteins, shown below.
TABLE-US-00011 RII-Specific AKAPs AKAP-KL (SEQ ID NO: 62)
PLEYQAGLLVQNAIQQAI AKAP79 (SEQ ID NO: 63) LLIETASSLVKNAIQLSI
AKAP-Lbc (SEQ ID NO: 64) LIEEAASRIVDAVIEQVK RI-Specific AKAPs
AKAPce (SEQ ID NO: 65) ALYQFADRFSELVISEAL RIAD (SEQ ID NO: 66)
LEQVANQLADQIIKEAT PV38 (SEQ ID NO: 67) FEELAWKIAKMIWSDVF
Dual-Specificity AKAPs AKAP7 (SEQ ID NO: 68) ELVRLSKRLVENAVLKAV
MAP2D (SEQ ID NO: 69) TAEEVSARIVQVVTAEAV DAKAP1 (SEQ ID NO: 70)
QIKQAAFQLISQVILEAT DAKAP2 (SEQ ID NO: 71) LAWKIAKMIVSDVMQQ
[0126] Stokka et al. (2006, Biochem J 400:493-99) also developed
peptide competitors of AKAP binding to PKA, shown in SEQ ID
NO:72-74. The peptide antagonists were designated as Ht31 (SEQ ID
NO:72), RIAD (SEQ ID NO:73) and PV-38 (SEQ ID NO:74). The Ht-31
peptide exhibited a greater affinity for the RII isoform of PKA,
while the RIAD and PV-38 showed higher affinity for RI.
TABLE-US-00012 Ht31 (SEQ ID NO: 72) DLIEEAASRIVDAVIEQVKAAGAY RIAD
(SEQ ID NO: 73) LEQYANQLADQIIKEATE PV-38 (SEQ ID NO: 74)
FEELAWKIAKMIWSDVFQQC
[0127] Hundsrucker et al. (2006, Biochem J 396:297-306) developed
still other peptide competitors for AKAP binding to PKA, with a
binding constant as low as 0.4 nM to the DDD of the RII form of
PKA. The sequences of various AKAP antagonistic peptides are
provided in Table 1 of Hundsrucker et al., reproduced in Table 4
below. AKAPIS represents a synthetic RII subunit-binding peptide.
All other peptides are derived from the RII-binding domains of the
indicated AKAPs.
TABLE-US-00013 TABLE 4 AKAP Peptide sequences Peptide Sequence
AKAPIS QIEYLAKQIVDNAIQQA (SEQ ID NO: 11) AKAPIS-P QIEYLAKQIPDNAIQQA
(SEQ ID NO: 75) Ht31 KGADLIEEAASRIVDAVIEQVKAAG (SEQ ID NO: 76)
Ht31-P KGADLIEEAASRIPDAPIEQVKAAG (SEQ ID NO: 77)
AKAP7.delta.-wt-pep PEDAELVRLSKRLVENAVLKAVQQY (SEQ ID NO: 78)
AKAP7.delta.-L304T-pep PEDAELVRTSKRLVENAVLKAVQQY (SEQ ID NO: 79)
AKAP7.delta.-L308D-pep PEDAELVRLSKRDVENAVLKAVQQY (SEQ ID NO: 80)
AKAP7.delta.-P-pep PEDAELVRLSKRLPENAVLKAVQQY (SEQ ID NO: 81)
AKAP7.delta.-PP-pep PEDAELVRLSKRLPENAPLKAVQQY (SEQ ID NO: 82)
AKAP7.delta.-L314E-pep PEDAELVRLSKRLVENAVEKAVQQY (SEQ ID NO: 83)
AKAP1-pep EEGLDRNEEIKRAAFQIISQVISEA (SEQ ID NO: 84) AKAP2-pep
LVDDPLEYQAGLLVQNAIQQAIAEQ (SEQ ID NO: 85) AKAP5-pep
QYETLLIETASSLVKNAIQLSIEQL (SEQ ID NO: 86) AKAP9-pep
LEKQYQEQLEEEVAKVIVSMSIAFA (SEQ ID NO: 87) AKAP10-pep
NTDEAQEELAWKIAKMIVSDIMQQA (SEQ ID NO: 88) AKAP11-pep
VNLDKKAVLAEKIVAEAIEKAEREL (SEQ ID NO: 89) AKAP12-pep
NGILELETKSSKLVQNIIQTAVDQF (SEQ ID NO: 90) AKAP14-pep
TQDKNYEDELTQVALALVEDVINYA (SEQ ID NO: 91) Rab32-pep
ETSAKDNINIEEAARFLVEKILVNH (SEQ ID NO: 92)
[0128] Residues that were highly conserved among the AD domains of
different AKAP proteins are indicated below by underlining with
reference to the AKAP IS sequence (SEQ ID NO:11). The residues are
the same as observed by Alto et al. (2003), with the addition of
the C-terminal alanine residue. (See FIG. 4 of Hundsrucker et al.
(2006), incorporated herein by reference.) The sequences of peptide
antagonists with particularly high affinities for the RII DDD
sequence were those of AKAP-IS, AKAP7.delta.-wt-pep,
AKAP7.delta.-L304T-pep and AKAP7.delta.-L308D-pep.
TABLE-US-00014 AKAP-IS (SEQ ID NO: 11) QIEYLAKQIVDNAIQQA
[0129] Carr et al. (2001, J Biol Chem 276:17332-38) examined the
degree of sequence homology between different AKAP-binding DDD
sequences from human and non-human proteins and identified residues
in the DDD sequences that appeared to be the most highly conserved
among different DDD moieties. These are indicated below by
underlining with reference to the human PKA RII.alpha. DDD sequence
of SEQ ID NO:9. Residues that were particularly conserved are
further indicated by italics. The residues overlap with, but are
not identical to those suggested by Kinderman et al. (2006) to be
important for binding to AKAP proteins. The skilled artisan will
realize that in designing sequence variants of DDD, it would be
most preferred to avoid changing the most conserved residues
(italicized), and it would be preferred to also avoid changing the
conserved residues (underlined), while conservative amino acid
substitutions may be considered for residues that are neither
underlined nor italicized.
TABLE-US-00015 (SEQ ID NO: 9)
SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA
[0130] A modified set of conservative amino acid substitutions for
the DDD1 (SEQ ID NO:9) sequence, based on the data of Carr et al.
(2001) is shown in Table 5. Even with this reduced set of
substituted sequences, there are over 65,000 possible alternative
DDD moiety sequences that may be produced, tested and used by the
skilled artisan without undue experimentation. The skilled artisan
could readily derive such alternative DDD amino acid sequences as
disclosed above for Table 2 and Table 3.
TABLE-US-00016 TABLE 5 Conservative Amino Acid Substitutions in
DDD1 (SEQ ID NO: 9). Consensus sequence disclosed as SEQ ID NO: 96.
S H I Q P T E Q V T N S I L A Q P V E V E T R R E A A N L D S K K L
L I I I V V V
[0131] The skilled artisan will realize that these and other amino
acid substitutions in the DDD or AD amino acid sequences may be
utilized to produce alternative species within the genus of AD or
DDD moieties, using techniques that are standard in the field and
only routine experimentation.
[0132] Alternative DNL.RTM. Structures
[0133] In certain alternative embodiments, DNL.RTM. constructs may
be formed using alternatively constructed antibodies or antibody
fragments, in which an AD moiety may be attached at the C-terminal
end of the kappa light chain (C.sub.k), instead of the C-terminal
end of the Fc on the heavy chain. The alternatively formed DNL.RTM.
constructs may be prepared as disclosed in Provisional U.S. Patent
Application Ser. Nos. 61/654,310, filed Jun. 1, 2012, 61/662,086,
filed Jun. 20, 2012, 61/673,553, filed Jul. 19, 2012, and
61/682,531, filed Aug. 13, 2012, the entire text of each
incorporated herein by reference. The light chain conjugated
DNL.RTM. constructs exhibit enhanced Fc-effector function activity
in vitro and improved pharmacokinetics, stability and anti-lymphoma
activity in vivo (Rossi et al., 2013, Bioconjug Chem 24:63-71).
[0134] C.sub.k-conjugated DNL.RTM. constructs may be prepared as
disclosed in Provisional U.S. Patent Application Ser. Nos.
61/654,310, 61/662,086, 61/673,553, and 61/682,531. Briefly,
C.sub.k-AD2-IgG, was generated by recombinant engineering, whereby
the AD2 peptide was fused to the C-terminal end of the kappa light
chain. Because the natural C-terminus of C.sub.K is a cysteine
residue, which forms a disulfide bridge to C.sub.H1, a 16-amino
acid residue "hinge" linker was used to space the AD2 from the
C.sub.K-V.sub.H1 disulfide bridge. The mammalian expression vectors
for C.sub.k-AD2-IgG-veltuzumab and C.sub.k-AD2-IgG-epratuzumab were
constructed using the pdHL2 vector, which was used previously for
expression of the homologous C.sub.H3-AD2-IgG modules. A 2208-bp
nucleotide sequence was synthesized comprising the pdHL2 vector
sequence ranging from the Bam HI restriction site within the
V.sub.K/C.sub.K intron to the Xho I restriction site 3' of the
C.sub.k intron, with the insertion of the coding sequence for the
hinge linker (EFPKPSTPPGSSGGAP, SEQ ID NO:93) and AD2, in frame at
the 3' end of the coding sequence for C.sub.K. This synthetic
sequence was inserted into the IgG-pdHL2 expression vectors for
veltuzumab and epratuzumab via Bam HI and Xho I restriction sites.
Generation of production clones with SpESFX-10 were performed as
described for the C.sub.H3-AD2-IgG modules.
C.sub.k-AD2-IgG-veltuzumab and C.sub.k-AD2-IgG-epratuzumab were
produced by stably-transfected production clones in batch roller
bottle culture, and purified from the supernatant fluid in a single
step using MabSelect (GE Healthcare) Protein A affinity
chromatography.
[0135] Following the same DNL.RTM. process described previously for
22-(20)-(20) (Rossi et al., 2009, Blood 113:6161-71),
C.sub.k-AD2-IgG-epratuzumab was conjugated with
C.sub.H1-DDD2-Fab-veltuzumab, a Fab-based module derived from
veltuzumab, to generate the bsHexAb 22*-(20)-(20), where the 22*
indicates the C.sub.k-AD2 module of epratuzumab and each (20)
symbolizes a stabilized dimer of veltuzumab Fab. The properties of
22*-(20)-(20) were compared with those of 22-(20)-(20), the
homologous Fc-bsHexAb comprising C.sub.H3-AD2-IgG-epratuzumab,
which has similar composition and molecular size, but a different
architecture.
[0136] Following the same DNL.RTM. process described previously for
20-2b (Rossi et al., 2009, Blood 114:3864-71),
C.sub.k-AD2-IgG-veltuzumab, was conjugated with IFN.alpha.2b-DDD2,
a module of IFN.alpha.2b with a DDD2 peptide fused at its
C-terminal end, to generate 20*-2b, which comprises veltuzumab with
a dimeric IFN.alpha.2b fused to each light chain. The properties of
20*-2b were compared with those of 20-2b, which is the homologous
Fc-IgG-IFN.alpha..
[0137] Each of the bsHexAbs and IgG-IFN.alpha. were isolated from
the DNL.RTM. reaction mixture by MabSelect affinity chromatography.
The two C.sub.k-derived prototypes, an anti-CD22/CD20 bispecific
hexavalent antibody, comprising epratuzumab (anti-CD22) and four
Fabs of veltuzumab (anti-CD20), and a CD20-targeting
immunocytokine, comprising veltuzumab and four molecules of
interferon-.alpha.2b, displayed enhanced Fc-effector functions in
vitro, as well as improved pharmacokinetics, stability and
anti-lymphoma activity in vivo, compared to their Fc-derived
counterparts.
[0138] Amino Acid Substitutions
[0139] In alternative embodiments, the disclosed methods and
compositions may involve production and use of proteins or peptides
with one or more substituted amino acid residues. For example, the
DDD and/or AD sequences used to make DNL.RTM. constructs may be
modified as discussed above.
[0140] The skilled artisan will be aware that, in general, amino
acid substitutions typically involve the replacement of an amino
acid with another amino acid of relatively similar properties
(i.e., conservative amino acid substitutions). The properties of
the various amino acids and effect of amino acid substitution on
protein structure and function have been the subject of extensive
study and knowledge in the art.
[0141] For example, the hydropathic index of amino acids may be
considered (Kyte & Doolittle, 1982, J. Mol. Biol.,
157:105-132). The relative hydropathic character of the amino acid
contributes to the secondary structure of the resultant protein,
which in turn defines the interaction of the protein with other
molecules. Each amino acid has been assigned a hydropathic index on
the basis of its hydrophobicity and charge characteristics (Kyte
& Doolittle, 1982), these are: isoleucine (+4.5); valine
(+4.2); leucine (+3.8); phenylalanine (+2.8); cysteine/cystine
(+2.5); methionine (+1.9); alanine (+1.8); glycine (-0.4);
threonine (-0.7); serine (-0.8); tryptophan (-0.9); tyrosine
(-1.3); proline (-1.6); histidine (-3.2); glutamate (-3.5);
glutamine (-3.5); aspartate (-3.5); asparagine (-3.5); lysine
(-3.9); and arginine (-4.5). In making conservative substitutions,
the use of amino acids whose hydropathic indices are within .+-.2
is preferred, within .+-.1 are more preferred, and within .+-.0.5
are even more preferred.
[0142] Amino acid substitution may also take into account the
hydrophilicity of the amino acid residue (e.g., U.S. Pat. No.
4,554,101). Hydrophilicity values have been assigned to amino acid
residues: arginine (+3.0); lysine (+3.0); aspartate (+3.0);
glutamate (+3.0); serine (+0.3); asparagine (+0.2); glutamine
(+0.2); glycine (0); threonine (-0.4); proline (-0.5 .+-. 1);
alanine (-0.5); histidine (-0.5); cysteine (-1.0); methionine
(-1.3); valine (-1.5); leucine (-1.8); isoleucine (-1.8); tyrosine
(-2.3); phenylalanine (-2.5); tryptophan (-3.4). Replacement of
amino acids with others of similar hydrophilicity is preferred.
[0143] Other considerations include the size of the amino acid side
chain. For example, it would generally not be preferred to replace
an amino acid with a compact side chain, such as glycine or serine,
with an amino acid with a bulky side chain, e.g., tryptophan or
tyrosine. The effect of various amino acid residues on protein
secondary structure is also a consideration. Through empirical
study, the effect of different amino acid residues on the tendency
of protein domains to adopt an alpha-helical, beta-sheet or reverse
turn secondary structure has been determined and is known in the
art (see, e.g., Chou & Fasman, 1974, Biochemistry, 13:222-245;
1978, Ann. Rev. Biochem., 47: 251-276; 1979, Biophys. J.,
26:367-384).
[0144] Based on such considerations and extensive empirical study,
tables of conservative amino acid substitutions have been
constructed and are known in the art. For example: arginine and
lysine; glutamate and aspartate; serine and threonine; glutamine
and asparagine; and valine, leucine and isoleucine. Alternatively:
Ala (A) leu, ile, val; Arg (R) gln, asn, lys; Asn (N) his, asp,
lys, arg, gln; Asp (D) asn, glu; Cys (C) ala, ser; Gln (Q) glu,
asn; Glu (E) gln, asp; Gly (G) ala; His (H) asn, gln, lys, arg; Ile
(I) val, met, ala, phe, leu; Leu (L) val, met, ala, phe, ile; Lys
(K) gln, asn, arg; Met (M) phe, ile, leu; Phe (F) leu, val, ile,
ala, tyr; Pro (P) ala; Ser (S), thr; Thr (T) ser; Trp (W) phe, tyr;
Tyr (Y) trp, phe, thr, ser; Val (V) ile, leu, met, phe, ala.
[0145] Other considerations for amino acid substitutions include
whether or not the residue is located in the interior of a protein
or is solvent exposed. For interior residues, conservative
substitutions would include: Asp and Asn; Ser and Thr; Ser and Ala;
Thr and Ala; Ala and Gly; Ile and Val; Val and Leu; Leu and Ile;
Leu and Met; Phe and Tyr; Tyr and Trp. (See, e.g., PROWL website at
rockefeller.edu) For solvent exposed residues, conservative
substitutions would include: Asp and Asn; Asp and Glu; Glu and Gln;
Glu and Ala; Gly and Asn; Ala and Pro; Ala and Gly; Ala and Ser;
Ala and Lys; Ser and Thr; Lys and Arg; Val and Leu; Leu and Ile;
Ile and Val; Phe and Tyr. (Id.) Various matrices have been
constructed to assist in selection of amino acid substitutions,
such as the PAM250 scoring matrix, Dayhoff matrix, Grantham matrix,
McLachlan matrix, Doolittle matrix, Henikoff matrix, Miyata matrix,
Fitch matrix, Jones matrix, Rao matrix, Levin matrix and Risler
matrix (Idem.)
[0146] In determining amino acid substitutions, one may also
consider the existence of intermolecular or intramolecular bonds,
such as formation of ionic bonds (salt bridges) between positively
charged residues (e.g., His, Arg, Lys) and negatively charged
residues (e.g., Asp, Glu) or disulfide bonds between nearby
cysteine residues.
[0147] Methods of substituting any amino acid for any other amino
acid in an encoded protein sequence are well known and a matter of
routine experimentation for the skilled artisan, for example by the
technique of site-directed mutagenesis or by synthesis and assembly
of oligonucleotides encoding an amino acid substitution and
splicing into an expression vector construct.
[0148] Pre-Targeting
[0149] Bispecific or multispecific antibodies may be of use in
pretargeting techniques. In this case, one or more diagnostic
and/or therapeutic agents may be conjugated to a targetable
construct that comprises one or more haptens. The hapten is
recognized by at least one arm of a bispecific or multispecific
antibody that also binds to a tumor-associated antigen or other
disease-associated antigen. In this case, the therapeutic agent
binds indirectly to the antibodies, via the binding of the
targetable construct. This process is referred to as
pretargeting.
[0150] Pre-targeting is a multistep process originally developed to
resolve the slow blood clearance of directly targeting antibodies,
which contributes to undesirable toxicity to normal tissues such as
bone marrow. With pre-targeting, a therapeutic agent is attached to
a small delivery molecule (targetable construct) that is cleared
within minutes from the blood. A pre-targeting bispecific or
multispecific antibody, which has binding sites for the targetable
construct as well as a target antigen, is administered first, free
antibody is allowed to clear from circulation and then the
targetable construct is administered.
[0151] Pre-targeting methods are disclosed, for example, in Goodwin
et al., U.S. Pat. No. 4,863,713; Goodwin et al., J. Nucl. Med.
29:226, 1988; Hnatowich et al., J. Nucl. Med. 28:1294, 1987; Oehr
et al., J. Nucl. Med. 29:728, 1988; Klibanov et al., J. Nucl. Med.
29:1951, 1988; Sinitsyn et al., J. Nucl. Med. 30:66, 1989;
Kalofonos et al., J. Nucl. Med. 31:1791, 1990; Schechter et al.,
Int. J. Cancer 48:167, 1991; Paganelli et al., Cancer Res. 51:5960,
1991; Paganelli et al., Nucl. Med. Commun. 12:211, 1991; U.S. Pat.
No. 5,256,395; Stickney et al., Cancer Res. 51:6650, 1991; Yuan et
al., Cancer Res. 51:3119, 1991; U.S. Pat. Nos. 6,077,499;
7,011,812; 7,300,644; 7,074,405; 6,962,702; 7,387,772; 7,052,872;
7,138,103; 6,090,381; 6,472,511; 6,962,702; and 6,962,702, each
incorporated herein by reference.
[0152] A pre-targeting method of diagnosing or treating a disease
or disorder in a subject may be provided by: (1) administering to
the subject a bispecific antibody or antibody fragment; (2)
optionally administering to the subject a clearing composition, and
allowing the composition to clear the antibody from circulation;
and (3) administering to the subject the targetable construct,
containing one or more chelated or chemically bound therapeutic or
diagnostic agents.
[0153] Targetable Constructs
[0154] In certain embodiments, targetable construct peptides
labeled with one or more therapeutic or diagnostic agents for use
in pre-targeting may be selected to bind to a bispecific antibody
with one or more binding sites for a targetable construct peptide
and one or more binding sites for a target antigen associated with
a disease or condition. Bispecific antibodies may be used in a
pretargeting technique wherein the antibody may be administered
first to a subject. Sufficient time may be allowed for the
bispecific antibody to bind to a target antigen and for unbound
antibody to clear from circulation. Then a targetable construct,
such as a labeled peptide, may be administered to the subject and
allowed to bind to the bispecific antibody and localize at the
diseased cell or tissue.
[0155] Such targetable constructs can be of diverse structure and
are selected not only for the availability of an antibody or
fragment that binds with high affinity to the targetable construct,
but also for rapid in vivo clearance when used within the
pre-targeting method and bispecific antibodies (bsAb) or
multispecific antibodies. Hydrophobic agents are best at eliciting
strong immune responses, whereas hydrophilic agents are preferred
for rapid in vivo clearance. Thus, a balance between hydrophobic
and hydrophilic character is established. This may be accomplished,
in part, by using hydrophilic chelating agents to offset the
inherent hydrophobicity of many organic moieties. Also, sub-units
of the targetable construct may be chosen which have opposite
solution properties, for example, peptides, which contain amino
acids, some of which are hydrophobic and some of which are
hydrophilic.
[0156] Peptides having as few as two amino acid residues,
preferably two to ten residues, may be used and may also be coupled
to other moieties, such as chelating agents. The linker should be a
low molecular weight conjugate, preferably having a molecular
weight of less than 50,000 daltons, and advantageously less than
about 20,000 daltons, 10,000 daltons or 5,000 daltons. More
usually, the targetable construct peptide will have four or more
residues and one or more haptens for binding, e.g., to a bispecific
antibody. Exemplary haptens may include In-DTPA (indium-diethylene
triamine pentaacetic acid) or HSG (histamine succinyl glycine). The
targetable construct may also comprise one or more chelating
moieties, such as DOTA
(1,4,7,10-tetraazacyclododecane1,4,7,10-tetraacetic acid), NOTA
(1,4,7-triaza-cyclononane-1,4,7-triacetic acid), TETA
(p-bromoacetamido-benzyl-tetraethylaminetetraacetic acid), NETA
([2-(4,7-biscarboxymethyl[1,4,7]triazacyclononan-1-yl-ethyl]-2-carbonylme-
thyl-amino]acetic acid) or other known chelating moieties.
Chelating moieties may be used, for example, to bind to a
therapeutic and or diagnostic radionuclide, paramagnetic ion or
contrast agent.
[0157] The targetable construct may also comprise unnatural amino
acids, e.g., D-amino acids, in the backbone structure to increase
the stability of the peptide in vivo. In alternative embodiments,
other backbone structures such as those constructed from
non-natural amino acids or peptoids may be used.
[0158] The peptides used as targetable constructs are conveniently
synthesized on an automated peptide synthesizer using a solid-phase
support and standard techniques of repetitive orthogonal
deprotection and coupling. Free amino groups in the peptide, that
are to be used later for conjugation of chelating moieties or other
agents, are advantageously blocked with standard protecting groups
such as a Boc group, while N-terminal residues may be acetylated to
increase serum stability. Such protecting groups are well known to
the skilled artisan. See Greene and Wuts Protective Groups in
Organic Synthesis, 1999 (John Wiley and Sons, N.Y.). When the
peptides are prepared for later use within the bispecific antibody
system, they are advantageously cleaved from the resins to generate
the corresponding C-terminal amides, in order to inhibit in vivo
carboxypeptidase activity.
[0159] Where pretargeting with bispecific antibodies is used, the
antibody will contain a first binding site for an antigen produced
by or associated with a target tissue and a second binding site for
a hapten on the targetable construct. Exemplary haptens include,
but are not limited to, HSG and In-DTPA. Antibodies raised to the
HSG hapten are known (e.g. 679 antibody) and can be easily
incorporated into the appropriate bispecific antibody (see, e.g.,
U.S. Pat. Nos. 6,962,702; 7,138,103 and 7,300,644, incorporated
herein by reference with respect to the Examples sections).
However, other haptens and antibodies that bind to them are known
in the art and may be used, such as In-DTPA and the 734 antibody
(e.g., U.S. Pat. No. 7,534,431, the Examples section incorporated
herein by reference).
[0160] Immunoconjugates
[0161] Various embodiments may involve use of immunoconjugates,
comprising an anti-Trop-2 antibody or antigen-binding fragment
thereof attached to one or more diagnostic or therapeutic agents.
In some embodiments, a drug or other agent may be attached to an
antibody or fragment thereof via a carrier moiety. Carrier moieties
may be attached, for example to reduced SH groups and/or to
carbohydrate side chains. A carrier moiety can be attached at the
hinge region of a reduced antibody component via disulfide bond
formation. Alternatively, such agents can be attached using a
heterobifunctional cross-linker, such as N-succinyl
3-(2-pyridyldithio)propionate (SPDP). Yu et al., Int. J. Cancer 56:
244 (1994). General techniques for such conjugation are well-known
in the art. See, for example, Wong, CHEMISTRY OF PROTEIN
CONJUGATION AND CROSS-LINKING (CRC Press 1991); Upeslacis et al.,
"Modification of Antibodies by Chemical Methods," in MONOCLONAL
ANTIBODIES: PRINCIPLES AND APPLICATIONS, Birch et al. (eds.), pages
187-230 (Wiley-Liss, Inc. 1995); Price, "Production and
Characterization of Synthetic Peptide-Derived Antibodies," in
MONOCLONAL ANTIBODIES: PRODUCTION, ENGINEERING AND CLINICAL
APPLICATION, Ritter et al. (eds.), pages 60-84 (Cambridge
University Press 1995). Alternatively, the carrier moiety can be
conjugated via a carbohydrate moiety in the Fc region of the
antibody.
[0162] Methods for conjugating functional groups to antibodies via
an antibody carbohydrate moiety are well-known to those of skill in
the art. See, for example, Shih et al., Int. J. Cancer 41: 832
(1988); Shih et al., Int. J. Cancer 46: 1101 (1990); and Shih et
al., U.S. Pat. No. 5,057,313, the Examples section of which is
incorporated herein by reference. The general method involves
reacting an antibody having an oxidized carbohydrate portion with a
carrier polymer that has at least one free amine function. This
reaction results in an initial Schiff base (imine) linkage, which
can be stabilized by reduction to a secondary amine to form the
final conjugate.
[0163] The Fc region may be absent if the antibody component is an
antibody fragment. However, it is possible to introduce a
carbohydrate moiety into the light chain variable region of a full
length antibody or antibody fragment. See, for example, Leung et
al., J. Immunol. 154: 5919 (1995); U.S. Pat. Nos. 5,443,953 and
6,254,868, the Examples section of which is incorporated herein by
reference. The engineered carbohydrate moiety is used to attach the
therapeutic or diagnostic agent.
[0164] An alternative method for attaching carrier moieties to a
targeting molecule involves use of click chemistry reactions. The
click chemistry approach was originally conceived as a method to
rapidly generate complex substances by joining small subunits
together in a modular fashion. (See, e.g., Kolb et al., 2004, Angew
Chem Int Ed 40:3004-31; Evans, 2007, Aust J Chem 60:384-95.)
Various forms of click chemistry reaction are known in the art,
such as the Huisgen 1,3-dipolar cycloaddition copper catalyzed
reaction (Tornoe et al., 2002, J Organic Chem 67:3057-64), which is
often referred to as the "click reaction." Other alternatives
include cycloaddition reactions such as the Diels-Alder,
nucleophilic substitution reactions (especially to small strained
rings like epoxy and aziridine compounds), carbonyl chemistry
formation of urea compounds and reactions involving carbon-carbon
double bonds, such as alkynes in thiol-yne reactions.
[0165] The azide alkyne Huisgen cycloaddition reaction uses a
copper catalyst in the presence of a reducing agent to catalyze the
reaction of a terminal alkyne group attached to a first molecule.
In the presence of a second molecule comprising an azide moiety,
the azide reacts with the activated alkyne to form a
1,4-disubstituted 1,2,3-triazole. The copper catalyzed reaction
occurs at room temperature and is sufficiently specific that
purification of the reaction product is often not required.
(Rostovstev et al., 2002, Angew Chem Int Ed 41:2596; Tornoe et al.,
2002, J Org Chem 67:3057.) The azide and alkyne functional groups
are largely inert towards biomolecules in aqueous medium, allowing
the reaction to occur in complex solutions. The triazole formed is
chemically stable and is not subject to enzymatic cleavage, making
the click chemistry product highly stable in biological systems.
Although the copper catalyst is toxic to living cells, the
copper-based click chemistry reaction may be used in vitro for
immunoconjugate formation.
[0166] A copper-free click reaction has been proposed for covalent
modification of biomolecules. (See, e.g., Agard et al., 2004, J Am
Chem Soc 126:15046-47.) The copper-free reaction uses ring strain
in place of the copper catalyst to promote a [3+2] azide-alkyne
cycloaddition reaction (Id.) For example, cyclooctyne is an
8-carbon ring structure comprising an internal alkyne bond. The
closed ring structure induces a substantial bond angle deformation
of the acetylene, which is highly reactive with azide groups to
form a triazole. Thus, cyclooctyne derivatives may be used for
copper-free click reactions (Id.)
[0167] Another type of copper-free click reaction was reported by
Ning et al. (2010, Angew Chem Int Ed 49:3065-68), involving
strain-promoted alkyne-nitrone cycloaddition. To address the slow
rate of the original cyclooctyne reaction, electron-withdrawing
groups are attached adjacent to the triple bond (Id.) Examples of
such substituted cyclooctynes include difluorinated cyclooctynes,
4-dibenzocyclooctynol and azacyclooctyne (Id.) An alternative
copper-free reaction involved strain-promoted alkyne-nitrone
cycloaddition to give N-alkylated isoxazolines (Id.) The reaction
was reported to have exceptionally fast reaction kinetics and was
used in a one-pot three-step protocol for site-specific
modification of peptides and proteins (Id.) Nitrones were prepared
by the condensation of appropriate aldehydes with
N-methylhydroxylamine and the cycloaddition reaction took place in
a mixture of acetonitrile and water (Id.) These and other known
click chemistry reactions may be used to attach carrier moieties to
antibodies in vitro.
[0168] Agard et al. (2004, J Am Chem Soc 126:15046-47) demonstrated
that a recombinant glycoprotein expressed in CHO cells in the
presence of peracetylated N-azidoacetylmannosamine resulted in the
bioincorporation of the corresponding N-azidoacetyl sialic acid in
the carbohydrates of the glycoprotein. The azido-derivatized
glycoprotein reacted specifically with a biotinylated cyclooctyne
to form a biotinylated glycoprotein, while control glycoprotein
without the azido moiety remained unlabeled (Id.) Laughlin et al.
(2008, Science 320:664-667) used a similar technique to
metabolically label cell-surface glycans in zebrafish embryos
incubated with peracetylated N-azidoacetylgalactosamine. The
azido-derivatized glycans reacted with difluorinated cyclooctyne
(DIFO) reagents to allow visualization of glycans in vivo.
[0169] The Diels-Alder reaction has also been used for in vivo
labeling of molecules. Rossin et al. (2010, Angew Chem Int Ed
49:3375-78) reported a 52% yield in vivo between a tumor-localized
anti-TAG72 (CC49) antibody carrying a trans-cyclooctene (TCO)
reactive moiety and an .sup.111In-labeled tetrazine DOTA
derivative. The TCO-labeled CC49 antibody was administered to mice
bearing colon cancer xenografts, followed 1 day later by injection
of .sup.111In-labeled tetrazine probe (Id.) The reaction of
radiolabeled probe with tumor localized antibody resulted in
pronounced radioactivity localization in the tumor, as demonstrated
by SPECT imaging of live mice three hours after injection of
radiolabeled probe, with a tumor-to-muscle ratio of 13:1 (Id.) The
results confirmed the in vivo chemical reaction of the TCO and
tetrazine-labeled molecules.
[0170] Antibody labeling techniques using biological incorporation
of labeling moieties are further disclosed in U.S. Pat. No.
6,953,675 (the Examples section of which is incorporated herein by
reference). Such "landscaped" antibodies were prepared to have
reactive ketone groups on glycosylated sites. The method involved
expressing cells transfected with an expression vector encoding an
antibody with one or more N-glycosylation sites in the CH1 or
V.kappa. domain in culture medium comprising a ketone derivative of
a saccharide or saccharide precursor. Ketone-derivatized
saccharides or precursors included N-levulinoyl mannosamine and
N-levulinoyl fucose. The landscaped antibodies were subsequently
reacted with agents comprising a ketone-reactive moiety, such as
hydrazide, hydrazine, hydroxylamino or thiosemicarbazide groups, to
form a labeled targeting molecule. Exemplary agents attached to the
landscaped antibodies included chelating agents like DTPA, large
drug molecules such as doxorubicin-dextran, and acyl-hydrazide
containing peptides. The landscaping technique is not limited to
producing antibodies comprising ketone moieties, but may be used
instead to introduce a click chemistry reactive group, such as a
nitrone, an azide or a cyclooctyne, onto an antibody or other
biological molecule.
[0171] Modifications of click chemistry reactions are suitable for
use in vitro or in vivo. Reactive targeting molecule may be formed
either by either chemical conjugation or by biological
incorporation. The targeting molecule, such as an antibody or
antibody fragment, may be activated with an azido moiety, a
substituted cyclooctyne or alkyne group, or a nitrone moiety. Where
the targeting molecule comprises an azido or nitrone group, the
corresponding targetable construct will comprise a substituted
cyclooctyne or alkyne group, and vice versa. Such activated
molecules may be made by metabolic incorporation in living cells,
as discussed above.
[0172] Alternatively, methods of chemical conjugation of such
moieties to biomolecules are well known in the art, and any such
known method may be utilized. General methods of immunoconjugate
formation are disclosed, for example, in U.S. Pat. Nos. 4,699,784;
4,824,659; 5,525,338; 5,677,427; 5,697,902; 5,716,595; 6,071,490;
6,187,284; 6,306,393; 6,548,275; 6,653,104; 6,962,702; 7,033,572;
7,147,856; and 7,259,240, the Examples section of each incorporated
herein by reference.
[0173] Diagnostic Agents
[0174] Diagnostic agents may comprise any detectable agent that may
be used to label a detection antibody, or to directly label a CTC,
and are preferably selected from the group consisting of a
radionuclide, a radiological contrast agent, a paramagnetic ion, a
metal, a fluorescent label, a chemiluminescent label, an ultrasound
contrast agent and a photoactive agent. Such diagnostic agents are
well known and any such known diagnostic agent may be used.
Non-limiting examples of diagnostic agents may include a
radionuclide such as .sup.110In, .sup.111In, .sup.177Lu, .sup.18F,
.sup.52Fe, .sup.62Cu, .sup.64Cu, .sup.67Cu, .sup.67Ga, .sup.68Ga,
.sup.86Y, .sup.90Y, .sup.89Zr, .sup.94mTc, .sup.94Tc, .sup.99mTc,
.sup.120I, .sup.123I, .sup.124I, .sup.125I, .sup.131I,
.sup.154-158Gd, .sup.32P, .sup.11C, .sup.13N, .sup.15O, .sup.186Re,
.sup.188Re, .sup.51Mn, .sup.52mMn, .sup.55Co, .sup.72As, .sup.75Br,
.sup.76Br, .sup.82mRb, .sup.83Sr, or other gamma-, beta-, or
positron-emitters. Paramagnetic ions of use may include chromium
(III), manganese (II), iron (III), iron (II), cobalt (II), nickel
(II), copper (II), neodymium (III), samarium (III), ytterbium
(III), gadolinium (III), vanadium (II), terbium (III), dysprosium
(III), holmium (III) or erbium (III). Metal contrast agents may
include lanthanum (III), gold (III), lead (II) or bismuth (III).
Ultrasound contrast agents may comprise liposomes, such as gas
filled liposomes. Radiopaque diagnostic agents may be selected from
compounds, barium compounds, gallium compounds, and thallium
compounds.
[0175] In certain embodiments, the fluorescent probe may be a
DYLIGHT.RTM. dye (Thermo Fisher Scientific, Rockford, Ill.). The
DYLIGHT.RTM. dye series are highly polar (hydrophilic), compatible
with aqueous buffers, photostable and exhibit high fluorescence
intensity. They remain highly fluorescent over a wide pH range and
are preferred for various applications. However, the skilled
artisan will realize that a variety of fluorescent dyes are known
and/or are commercially available and may be utilized. Other
fluorescent agents include, but are not limited to, dansyl
chloride, rhodamine isothiocyanate, Alexa 350, Alexa 430, AMCA,
aminoacridine, BODIPY 630/650, BODIPY 650/665, BODIPY-FL,
BODIPY-R6G, BODIPY-TMR, BODIPY-TRX,
5-carboxy-4',5'-dichloro-2',7'-dimethoxy fluorescein,
5-carboxy-2',4',5',7'-tetrachlorofluorescein, 5-carboxyfluorescein,
5-carboxyrhodamine, 6-carboxyrhodamine, 6-carboxytetramethyl amino,
Cascade Blue, Cy2, Cy3, Cy5,6-FAM, dansyl chloride, fluorescein,
HEX, 6-JOE, NBD (7-nitrobenz-2-oxa-1,3-diazole), Oregon Green 488,
Oregon Green 500, Oregon Green 514, Pacific Blue, phthalic acid,
terephthalic acid, isophthalic acid, cresyl fast violet, cresyl
blue violet, brilliant cresyl blue, para-aminobenzoic acid,
erythrosine, phthalocyanines, azomethines, cyanines, xanthines,
succinylfluoresceins, rare earth metal cryptates, europium
trisbipyridine diamine, a europium cryptate or chelate, diamine,
dicyanins, La Jolla blue dye, allopycocyanin, allococyanin B,
phycocyanin C, phycocyanin R, thiamine, phycoerythrocyanin,
phycoerythrin R, REG, Rhodamine Green, rhodamine isothiocyanate,
Rhodamine Red, ROX, TAMRA, TET, TRIT (tetramethyl rhodamine
isothiol), Tetramethylrhodamine, and Texas Red. (See, e.g., U.S.
Pat. Nos. 5,800,992; 6,319,668.) These and other luminescent labels
may be obtained from commercial sources such as Molecular Probes
(Eugene, Oreg.), and EMD Biosciences (San Diego, Calif.).
[0176] Chemiluminescent labels of use may include luminol,
isoluminol, an aromatic acridinium ester, an imidazole, an
acridinium salt or an oxalate ester.
[0177] Therapeutic Agents
[0178] A wide variety of therapeutic reagents can be administered
concurrently or sequentially with an anti-Trop-2 or other anti-TAA
antibody. Alternatively, such agents may be conjugated to
antibodies, for example, drugs, toxins, oligonucleotides,
immunomodulators, hormones, hormone antagonists, enzymes, enzyme
inhibitors, radionuclides, angiogenesis inhibitors, etc.
Therapeutic agents include, for example, cytotoxic drugs such as
vinca alkaloids, anthracyclines such as doxorubicin, 2-PDox or
pro-2-PDox, gemcitabine, epipodophyllotoxins, taxanes,
antimetabolites, alkylating agents, antibiotics, SN-38, COX-2
inhibitors, antimitotics, anti-angiogenic and pro-apoptotic agents,
particularly doxorubicin, methotrexate, taxol, CPT-11,
camptothecans, proteosome inhibitors, mTOR inhibitors, HDAC
inhibitors, tyrosine kinase inhibitors, and others. Other useful
anti-cancer cytotoxic drugs include nitrogen mustards, alkyl
sulfonates, nitrosoureas, triazenes, folic acid analogs, COX-2
inhibitors, antimetabolites, pyrimidine analogs, purine analogs,
platinum coordination complexes, mTOR inhibitors, tyrosine kinase
inhibitors, proteosome inhibitors, HDAC inhibitors, camptothecins,
hormones, and the like. Suitable cytotoxic agents are described in
REMINGTON'S PHARMACEUTICAL SCIENCES, 19th Ed. (Mack Publishing Co.
1995), and in GOODMAN AND GILMAN'S THE PHARMACOLOGICAL BASIS OF
THERAPEUTICS, 7th Ed. (MacMillan Publishing Co. 1985), as well as
revised editions of these publications. Other suitable cytotoxic
agents, such as experimental drugs, are known to those of skill in
the art. In a preferred embodiment, conjugates of camptothecins and
related compounds, such as SN-38, may be conjugated to anti-Trop-2
or other anti-TAA antibodies. In another preferred embodiment,
gemcitabine is administered to the subject in conjunction with
SN-38-hRS7 and/or .sup.90Y-hPAM4.
[0179] A toxin can be of animal, plant or microbial origin. Toxins
of use include ricin, abrin, ribonuclease (RNase), DNase I,
Staphylococcal enterotoxin-A, pokeweed antiviral protein, onconase,
gelonin, diphtheria toxin, Pseudomonas exotoxin, and Pseudomonas
endotoxin. See, for example, Pastan et al., Cell 47:641 (1986),
Goldenberg, C A--A Cancer Journal for Clinicians 44:43 (1994),
Sharkey and Goldenberg, C A--A Cancer Journal for Clinicians 56:226
(2006). Additional toxins suitable for use are known to those of
skill in the art and are disclosed in U.S. Pat. No. 6,077,499, the
Examples section of which is incorporated herein by reference.
[0180] As used herein, the term "immunomodulator" includes a
cytokine, a lymphokine, a monokine, a stem cell growth factor, a
lymphotoxin, a hematopoietic factor, a colony stimulating factor
(CSF), an interferon (IFN), parathyroid hormone, thyroxine,
insulin, proinsulin, relaxin, prorelaxin, follicle stimulating
hormone (FSH), thyroid stimulating hormone (TSH), luteinizing
hormone (LH), hepatic growth factor, prostaglandin, fibroblast
growth factor, prolactin, placental lactogen, OB protein, a
transforming growth factor (TGF), TGF-.alpha., TGF-.beta.,
insulin-like growth factor (ILGF), erythropoietin, thrombopoietin,
tumor necrosis factor (TNF), TNF-.alpha., TNF-.beta., a
mullerian-inhibiting substance, mouse gonadotropin-associated
peptide, inhibin, activin, vascular endothelial growth factor,
integrin, interleukin (IL), granulocyte-colony stimulating factor
(G-CSF), granulocyte macrophage-colony stimulating factor (GM-CSF),
interferon-.alpha., interferon-.beta., interferon-.gamma.,
interferon-.lamda., S1 factor, IL-1, IL-1cc, IL-2, IL-3, IL-4,
IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12, IL-13, IL-14,
IL-15, IL-16, IL-17, IL-18 IL-21 and IL-25, LIF, kit-ligand, FLT-3,
angiostatin, thrombospondin, endostatin, lymphotoxin, and the
like.
[0181] Particularly useful therapeutic radionuclides include, but
are not limited to .sup.111In, .sup.177Lu, .sup.212Bi, .sup.213Bi,
.sup.211At, .sup.62Cu, .sup.64Cu, .sup.67Cu, .sup.90Y, .sup.125I,
.sup.131I, .sup.32P, .sup.33P, .sup.47Sc, .sup.111Ag, .sup.67Ga,
.sup.142Pr, .sup.153Sm, .sup.161Tb, .sup.166Dy, .sup.166Ho,
.sup.186Re, .sup.188Re, .sup.189Re, .sup.212Pb, .sup.223Ra,
.sup.225Ac, .sup.59Fe, .sup.75Se, .sup.77As, .sup.89Sr, .sup.99Mo,
.sup.105Rh, .sup.109Pd, .sup.143Pr, .sup.149Pm, .sup.169Er,
.sup.194Ir, .sup.198Au, .sup.199Au, .sup.227Th, and .sup.211Pb. The
therapeutic radionuclide preferably has a decay energy in the range
of 20 to 6,000 keV, preferably in the ranges 60 to 200 keV for an
Auger emitter, 100-2,500 keV for a beta emitter, and 4,000-6,000
keV for an alpha emitter. Maximum decay energies of useful
beta-particle-emitting nuclides are preferably 20-5,000 keV, more
preferably 100-4,000 keV, and most preferably 500-2,500 keV. Also
preferred are radionuclides that substantially decay with
Auger-emitting particles. For example, Co-58, Ga-67, Br-80m,
Tc-99m, Rh-103m, Pt-109, In-111, Sb-119, I-125, Ho-161, Os-189m and
Ir-192. Decay energies of useful beta-particle-emitting nuclides
are preferably <1,000 keV, more preferably <100 keV, and most
preferably <70 keV. Also preferred are radionuclides that
substantially decay with generation of alpha-particles. Such
radionuclides include, but are not limited to: Dy-152, At-211,
Bi-212, Ra-223, Rn-219, Po-215, Bi-211, Ac-225, Fr-221, At-217,
Bi-213, Fm-255 and Th-227. Decay energies of useful
alpha-particle-emitting radionuclides are preferably 2,000-10,000
keV, more preferably 3,000-8,000 keV, and most preferably
4,000-7,000 keV.
[0182] For example, .sup.90Y, which emits an energetic beta
particle, can be coupled to an antibody, antibody fragment or
fusion protein, using diethylenetriaminepentaacetic acid (DTPA), or
more preferably using DOTA. Methods of conjugating .sup.90Y to
antibodies or targetable constructs are known in the art and any
such known methods may be used. (See, e.g., U.S. Pat. No.
7,259,249, the Examples section of which is incorporated herein by
reference. See also Linden et al., Clin Cancer Res. 11:5215-22,
2005; Sharkey et al., J Nucl Med. 46:620-33, 2005; Sharkey et al.,
J Nucl Med. 44:2000-18, 2003.)
[0183] Additional potential therapeutic radioisotopes include
.sup.11C, .sup.13N, .sup.15O, .sup.75Br, .sup.198Au, .sup.224Ac,
.sup.126I, .sup.133I, .sup.77Br, .sup.113mIn, .sup.95Ru, .sup.97Ru,
.sup.103Ru, .sup.105Ru, .sup.107Hg, .sup.203Hg, .sup.121mTe,
.sup.122mTe, .sup.125mTe, .sup.165Tm, .sup.167Tm, .sup.168Tm,
.sup.197Pt, .sup.109Pd, .sup.105Rh, .sup.142Pr, .sup.143Pr,
.sup.161Tb, .sup.166Ho, .sup.199Au, .sup.57Co, .sup.58Co,
.sup.51Cr, .sup.59Fe, .sup.75Se, .sup.201Tl, .sup.225Ac, .sup.76Br,
.sup.169Yb, and the like.
[0184] In another embodiment, a radiosensitizer can be used in
combination with a naked or conjugated antibody or antibody
fragment. For example, the radiosensitizer can be used in
combination with a radiolabeled antibody or antibody fragment. The
addition of the radiosensitizer can result in enhanced efficacy
when compared to treatment with the radiolabeled antibody or
antibody fragment alone. Radiosensitizers are described in D. M.
Goldenberg (ed.), CANCER THERAPY WITH RADIOLABELED ANTIBODIES, CRC
Press (1995). Other typical radiosensitizers of interest for use
with this technology include gemcitabine, 5-fluorouracil, and
cisplatin, and have been used in combination with external
irradiation in the therapy of diverse cancers.
[0185] Antibodies or fragments thereof that have a boron
addend-loaded carrier for thermal neutron activation therapy will
normally be affected in similar ways. However, it will be
advantageous to wait until non-targeted immunoconjugate clears
before neutron irradiation is performed. Clearance can be
accelerated using an anti-idiotypic antibody that binds to the
anti-cancer antibody. See U.S. Pat. No. 4,624,846 for a description
of this general principle. For example, boron addends such as
carboranes, can be attached to antibodies. Carboranes can be
prepared with carboxyl functions on pendant side chains, as is
well-known in the art. Attachment of carboranes to a carrier, such
as aminodextran, can be achieved by activation of the carboxyl
groups of the carboranes and condensation with amines on the
carrier. The intermediate conjugate is then conjugated to the
antibody. After administration of the antibody conjugate, a boron
addend is activated by thermal neutron irradiation and converted to
radioactive atoms which decay by alpha-emission to produce highly
toxic, short-range effects.
[0186] Formulation and Administration
[0187] Where therapeutic antibodies are to be administered in vivo,
suitable routes of administration may include, without limitation,
oral, parenteral, rectal, transmucosal, intestinal administration,
intramedullary, intrathecal, direct intraventricular, intravenous,
intravitreal, intracavitary, intraperitoneal, or intratumoral
injections. The preferred routes of administration are parenteral,
more preferably intravenous. Alternatively, one may administer the
compound in a local rather than systemic manner, for example, via
injection of the compound directly into a solid or hematological
tumor.
[0188] Antibodies can be formulated according to known methods to
prepare pharmaceutically useful compositions, whereby the antibody
is combined in a mixture with a pharmaceutically suitable
excipient. Sterile phosphate-buffered saline is one example of a
pharmaceutically suitable excipient. Other suitable excipients are
well-known to those in the art. See, for example, Ansel et al.,
PHARMACEUTICAL DOSAGE FORMS AND DRUG DELIVERY SYSTEMS, 5th Edition
(Lea & Febiger 1990), and Gennaro (ed.), REMINGTON'S
PHARMACEUTICAL SCIENCES, 18th Edition (Mack Publishing Company
1990), and revised editions thereof.
[0189] In a preferred embodiment, the antibody is formulated in
Good's biological buffer (pH 6-7), using a buffer selected from the
group consisting of N-(2-acetamido)-2-aminoethanesulfonic acid
(ACES); N-(2-acetamido)iminodiacetic acid (ADA);
N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES);
4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES);
2-(N-morpholino)ethanesulfonic acid (MES);
3-(N-morpholino)propanesulfonic acid (MOPS);
3-(N-morpholinyl)-2-hydroxypropanesulfonic acid (MOPSO); and
piperazine-N,N'-bis(2-ethanesulfonic acid) [Pipes]. More preferred
buffers are MES or MOPS, preferably in the concentration range of
20 to 100 mM, more preferably about 25 mM. Most preferred is 25 mM
MES, pH 6.5. The formulation may further comprise 25 mM trehalose
and 0.01% v/v polysorbate 80 as excipients, with the final buffer
concentration modified to 22.25 mM as a result of added excipients.
The preferred method of storage is as a lyophilized formulation of
the conjugates, stored in the temperature range of -20.degree. C.
to 2.degree. C., with the most preferred storage at 2.degree. C. to
8.degree. C.
[0190] The antibody can be formulated for intravenous
administration via, for example, bolus injection, slow infusion or
continuous infusion. Preferably, the antibody of the present
invention is infused over a period of less than about 4 hours, and
more preferably, over a period of less than about 3 hours. For
example, the first 25-50 mg could be infused within 30 minutes,
preferably even 15 min, and the remainder infused over the next 2-3
hrs. Formulations for injection can be presented in unit dosage
form, e.g., in ampoules or in multi-dose containers, with an added
preservative. The compositions can take such forms as suspensions,
solutions or emulsions in oily or aqueous vehicles, and can contain
formulatory agents such as suspending, stabilizing and/or
dispersing agents. Alternatively, the active ingredient can be in
powder form for constitution with a suitable vehicle, e.g., sterile
pyrogen-free water, before use.
[0191] Additional pharmaceutical methods may be employed to control
the duration of action of the therapeutic conjugate. Control
release preparations can be prepared through the use of polymers to
complex or adsorb the antibody. For example, biocompatible polymers
include matrices of poly(ethylene-co-vinyl acetate) and matrices of
a polyanhydride copolymer of a stearic acid dimer and sebacic acid.
Sherwood et al., Bio/Technology 10: 1446 (1992). The rate of
release of an antibody from such a matrix depends upon the
molecular weight of the antibody, the amount of antibody within the
matrix, and the size of dispersed particles. Saltzman et al.,
Biophys. J. 55: 163 (1989); Sherwood et al., supra. Other solid
dosage forms are described in Ansel et al., PHARMACEUTICAL DOSAGE
FORMS AND DRUG DELIVERY SYSTEMS, 5th Edition (Lea & Febiger
1990), and Gennaro (ed.), REMINGTON'S PHARMACEUTICAL SCIENCES, 18th
Edition (Mack Publishing Company 1990), and revised editions
thereof.
[0192] Generally, the dosage of an administered antibody for humans
will vary depending upon such factors as the patient's age, weight,
height, sex, general medical condition and previous medical
history. It may be desirable to provide the recipient with a dosage
of antibody that is in the range of from about 0.3 mg/kg to 5 mg/kg
as a single intravenous infusion, although a lower or higher dosage
also may be administered as circumstances dictate. A dosage of
0.3-5 mg/kg for a 70 kg patient, for example, is 21-350 mg, or
12-206 mg/m.sup.2 for a 1.7-m patient. The dosage may be repeated
as needed, for example, once per week for 2-10 weeks, once per week
for 8 weeks, or once per week for 4 weeks. It may also be given
less frequently, such as every other week for several months, or
monthly or quarterly for many months, as needed in a maintenance
therapy. Preferred dosages may include, but are not limited to, 0.3
mg/kg, 0.5 mg/kg, 0.7 mg/kg, 1.0 mg/kg, 1.2 mg/kg, 1.5 mg/kg, 2.0
mg/kg, 2.5 mg/kg, 3.0 mg/kg, 3.5 mg/kg, 4.0 mg/kg, 4.5 mg/kg, and
5.0 mg/kg. More preferred dosages are 0.6 mg/kg for weekly
administration and 1.2 mg/kg for less frequent dosing. Any amount
in the range of 0.3 to 5 mg/kg may be used. The dosage is
preferably administered multiple times, once a week. A minimum
dosage schedule of 4 weeks, more preferably 8 weeks, more
preferably 16 weeks or longer may be used, with the dose frequency
dependent on toxic side-effects and recovery therefrom, mostly
related to hematological toxicities. The schedule of administration
may comprise administration once or twice a week, on a cycle
selected from the group consisting of: (i) weekly; (ii) every other
week; (iii) one week of therapy followed by two, three or four
weeks off; (iv) two weeks of therapy followed by one, two, three or
four weeks off; (v) three weeks of therapy followed by one, two,
three, four or five week off; (vi) four weeks of therapy followed
by one, two, three, four or five week off; (vii) five weeks of
therapy followed by one, two, three, four or five week off; and
(viii) monthly. The cycle may be repeated 2, 4, 6, 8, 10, or 12
times or more.
[0193] Alternatively, an antibody may be administered as one dosage
every 2 or 3 weeks, repeated for a total of at least 3 dosages. Or,
twice per week for 4-6 weeks. The dosage may be administered once
every other week or even less frequently, so the patient can
recover from any drug-related toxicities. Alternatively, the dosage
schedule may be decreased, namely every 2 or 3 weeks for 2-3
months. The dosing schedule can optionally be repeated at other
intervals and dosage may be given through various parenteral
routes, with appropriate adjustment of the dose and schedule.
[0194] The methods and compositions described and claimed herein
may be used to treat malignant or premalignant conditions and to
prevent progression to a neoplastic or malignant state, including
but not limited to those disorders described above. Such uses are
indicated in conditions known or suspected of preceding progression
to neoplasia or cancer, in particular, where non-neoplastic cell
growth consisting of hyperplasia, metaplasia, or most particularly,
dysplasia has occurred (for review of such abnormal growth
conditions, see Robbins and Angell, Basic Pathology, 2d Ed., W. B.
Saunders Co., Philadelphia, pp. 68-79 (1976)).
[0195] Dysplasia is frequently a forerunner of cancer, and is found
mainly in the epithelia. It is the most disorderly form of
non-neoplastic cell growth, involving a loss in individual cell
uniformity and in the architectural orientation of cells. Dysplasia
characteristically occurs where there exists chronic irritation or
inflammation. In preferred embodiments, the method of the invention
is used to inhibit growth, progression, and/or metastasis of
cancers, in particular those listed above.
[0196] Kits
[0197] Various embodiments may concern kits containing components
suitable for detecting Trop-2 positive CTCs in a patient. Exemplary
kits may contain at least one anti-Trop-2 antibody as described
herein. In certain embodiments, the antibody may be conjugated to
at least one diagnostic agent. In alternative embodiments, a second
antibody that binds to a Trop-2 positive CTC may be included. The
second antibody may bind to a different epitope of Trop-2 or to a
different TAA, and may be labeled with at least one diagnostic
agent. In certain embodiments, an anti-Trop-2 antibody or antigen
binding fragment thereof may be provided in the form of a prefilled
syringe or vial containing a sterile, liquid formulation or
lyophilized preparation of antibody (e.g., Kivitz et al., Clin.
Ther. 2006, 28:1619-29).
[0198] The kit components may be packaged together or separated
into two or more containers. In some embodiments, the containers
may be vials that contain sterile, lyophilized formulations of a
composition that are suitable for reconstitution. A kit may also
contain one or more buffers suitable for reconstitution and/or
dilution of other reagents. Other containers that may be used
include, but are not limited to, a pouch, tray, box, tube, or the
like. Kit components may be packaged and maintained sterilely
within the containers. Another component that can be included is
instructions for use of the kit.
EXAMPLES
[0199] The examples below are illustrative of embodiments of the
current invention and are not limiting to the scope of the
claims.
Example 1
Cell Binding Assay of Anti-Trop-2 Antibodies
[0200] Two different murine monoclonal antibodies against human
Trop-2 were obtained. The first, 162-46.2, was purified from a
hybridoma (ATCC, HB-187) grown up in roller-bottles. A second
antibody, MAB650, was purchased from R&D Systems (Minneapolis,
Minn.). For a comparison of binding, the Trop-2-positive human
gastric carcinoma, NCI-N87, was used as the target. Cells
(1.5.times.10.sup.5/well) were plated into 96-well plates the day
before the binding assay. The following morning, a dose/response
curve was generated with 162-46.2, MAB650, and murine RS7 (0.03 to
66 nM) (not shown). These primary antibodies were incubated with
the cells for 1.5 h at 4.degree. C. Wells were washed and an
anti-mouse-HRP secondary antibody was added to all the wells for 1
h at 4.degree. C. Wells are washed again followed by the addition
of a luminescence substrate. Plates were read using Envision plate
reader and values are reported as relative luminescent units.
[0201] All three antibodies had similar K.sub.D-values of 0.57 nM
for RS7, 0.52 nM for 162-46.2 and 0.49 nM for MAB650 (not shown).
However, when comparing the maximum binding (B.sub.max) of 162-46.2
and MAB650 to RS7 they were reduced by 25% and 50%, respectively
(B.sub.Max 11,250 for RS7, 8,471 for 162-46.2 and 6,018 for MAB650)
indicating different binding properties in comparison to RS7 (not
shown).
Example 2
Collection and Storage of Blood Samples
[0202] Ten mL blood samples are drawn from each of 10 healthy
donors and 20 patients with metastatic breast cancer and dispensed
into a CELLSAVE.TM. Preservative tube (Jassen Diagnostics LLC,
Raritan, N.J.). The samples are stored at RT and processed within
72 h of blood collection (Allard et al., 2004, Clin Cancer Res, 10:
6897). Alternatively, 10 mL of blood samples are drawn into a
CYTOCHEX.RTM. Blood collection tube (Streck, Omaha, Nebr.),
maintained at RT, and processed within 7 days (Ng et al., 2012 J
Immunol Methods, 385: 79). Blood can also be drawn into 10 mL
K2EDTA VACUTAINER.RTM. (BD, Waltham, Mass.), fixed with the
LIQUIDBIOPSY.RTM. fixative (Cynvenio Biosystems, Westlake Village,
Calif.)) within 4 h of collection, stored at room temperature, and
processed within 96 h of fixation.
Example 3
Spiking of Cancer Cells in Blood Samples from Healthy Donors
[0203] SK-BR-3 and BxPC-3 cells, both expressing high levels of
Trop-2, are cultured in their designated medium, and harvested
using trypsin. The viability and cell number of the resulting cell
suspensions are assessed by Guava EASYCYTE.TM. flow cytometer. The
cell suspensions are used only when their viability exceeds 90%.
The number of cells spiked into normal serum is from 1 to 100 per
mL. Cancer cells that express moderate levels of Trop-2, for
example, MCF-7, LoVo, and LS 174 T, low levels of Trop-2, for
example, HT-29, or are negative for Trop-2, for example, A549 and
H460, can also be used to spike blood samples.
Example 4
Isolation of Epithelial Cancer Cells from Spiked Blood Samples with
the Use of a Magnetic Device
[0204] Blood samples spiked with epithelial cancer cells are
incubated with biotinylated tri-Fab hRS7 (biotin-E1/3, prepared by
the DNL.RTM. technique described above), and ferrofluids coated
with streptavidin (FF-SV) to immunomagnetically enrich epithelial
cells. Briefly, 7.5 mL of a blood sample containing a known number
of spiked BxPC-3 or SK-BR-3 are mixed with 6 mL of buffer, and
centrifuged at 800.times.g for 10 min. After removing the plasma
and buffer layer, biotin-E1/3 and FF-SV are added and incubated for
1 h. Subsequently, unlabeled cells are removed from labeled cells
following magnetic separation. Cells labeled with biotin-E1/3 are
then detached from FF-SV with a further wash and centrifugation,
and are analyzed by flow cytometry after labeling with DAPI,
PE-anti-CK18, and APC-anti-CD45. Nucleated cells lacking CD45 and
expressing cytokeratin (CK8, CK18, CK19) are generally defined as
CTCs (Swaby & Cristofanilli, 2011, BMC Medicine, 9: 43).
Example 5
Isolation of Epithelial Cancer Cells from Spiked Blood Samples
without the Use of a Magnetic Device
[0205] Blood samples spiked with epithelial cancer cells are
incubated with biotin-E1/3 in a microvortex-generating
herringbone-chip (HP-Chip) chemically modified with avidin as
described by Stott et al (2010, PNAS, 107: 18392), or more
preferably, are incubated with biotin-E1/3 for 1 h before adding to
NanoVelcro chips functionalized with streptavidin as described by
Lu et al. (2013, Methods, 64: 144). After rinsing away the unbound
cells, the bound cells are analyzed for CTCs as described in
Example 3.
Example 6
Detection of Epithelial Cancer Cells from Spiked Blood Samples
without Prior Enrichment
[0206] Red blood cells in blood samples spiked with BxPC-3 are
lysed with ammonium chloride, and centrifuged. The cell pellets are
collected and incubated with FITC-labeled E1/3. The live cells in
suspension are then applied to a poly-lysine-treated slide and
analyzed with a laser scanning cytometer (Pachmann et al., 2005,
Breast Cancer Res, 7: R975). Alternatively, the cell pellets
collected after lysis of red blood cells are incubated with a
cocktail comprising biotinylated E1/3 and one or more of other
biotinylated DNL.RTM. conjugates in the presence of FITC-labeled
avidin. The live cells in suspension are then analyzed by laser
scanning cytometer.
Example 7
Detection of Epithelial Cancer Cells from Spiked Blood Samples
Using a Bispecific Construct Targeting both Trop-2 and EGFR
[0207] Blood samples spiked with BxPC-3 cells, which express high
levels of both Trop-2 and EGFR, are incubated with a biotinylated
bispecific Tri-Fab, designated (E1)-225, and ferrofluids coated
with streptavidin (FF-SV), as described in Example 4. (E1)-225 is
generated by conjugating C.sub.H1-DDD2-Fab-hRS7 to
C.sub.H1-AD2-Fab-c225, thus providing bivalent and monovalent
binding to Trop-2 and EGFR, respectively. When compared with the
enrichment using only monospecific hRS7 or c225 (cetuximab), the
bispecific (E1)-225 is able to capture more BxPC-3 spiked into the
blood samples, with less contamination of CD45-positive white blood
cells.
Example 8
Detection of Trop-2.sup.+ CTCs Using LIQUIDBIOPSY.RTM. System
[0208] A LIQUIDBIOPSY.RTM. instrument (Cat. No. A28188),
LIQUIDBIOPSY.RTM. Blood Collection Kit (Cat. No. A28171) and
LIQUIDBIOPSY.RTM. Reagents and Consumables Kits (Cat. Nos. A28186,
A28187) are obtained from Life Technologies, ThermoFisher (Grand
Island, N.Y.). The LIQUIDBIOPSY.RTM. kits includes a stabilization
protocol for whole-blood samples, allowing unrefrigerated shipping
of samples (96-hour window), as well as buffers, reagents, vials,
elution tubes, and flow cells to process blood samples.
[0209] The humanized RS7 (hRS7) monoclonal antibody (sacituzumab)
is biotinylated using the protocols and reagents provided with the
Reagents and Consumables kit. Biotinylated hRS7 (sacituzumab) is
used in place of the anti-EpCAM biotinylated antibody provided with
the Reagents and Consumables Kit. Alternatively, anti-TROP-2
Biotinylated Antibody (Cat. No. BAF650, R&D Systems,
Minneapolis, Minn.) is used in place of anti-EpCAM.
[0210] Circulating tumor cells from the blood of patients with
solid tumors are isolated using the anti-TROP-2 biotinylated
antibody and the instrument and reagents discussed above, according
to the manufacturer's instructions. Isolated tumor cells are
released from the slide, and confirmed by flow cytometry after
labeling with DAPI, PE-anti-CK18, and APC-anti-CD45, as described
in Example 3. Released cells from a second blood specimen are
cultured, and a colony of live cells is obtained, which are
isolated and analyzed by FISH for the copy number of Trop-2 and
chromosome-1 using specific probes available from Empire Genomics
(Buffalo, N.Y.). FIG. 1 and FIG. 2 are representative results
obtained in MCF-7 (Trop-2-positive) and A549 (Trop-2-negative)
cells, showing 3 and 2 copies of the Trop-2 gene, respectively. In
addition, the copy number of topoisomerase-I (TOP1) and
chromosome-20 are also determined using specific probes provided by
Abnova (Taipei, Taiwan) and documented. FIG. 3 and FIG. 4 are
representative results obtained in MCF-7 and A549 cells, showing 7
and 3 copies of the TOP1 gene, respectively. The simultaneous
detection and quantitation of copy numbers of Trop-2 and TOP1 allow
the determination of cancer cells that also express TOP1, which
would indicate which patient tumors may be particularly responsive
or resistant to a TOP1-inhibitor therapy, such as with irinotecan.
This is particularly useful when using sacituzumab govitecan
(IMMU-132), which targets Trop-2-expressing cancer cells and
delivers SN-38 selectively to such cells. Recovery of tumor cells
from blood samples is compared using anti-Trop-2 hRS7 antibody
versus the anti-EpCAM antibody provided with the kit. Surprisingly,
recovery of CTCs is higher with the anti-Trop-2 antibody than the
anti-EpCAM antibody.
Example 9
Isolation of Trop-2.sup.+ CTCs with IMAG.TM. Magnetic Particles
[0211] Purified mouse anti-human Trop-2 antibody is prepared from
clone 162-46, purchased from BD Pharmingen (San Jose, Calif.). The
anti-Trop-2 antibody is biotinylated as described in Example 7.
IMAG.TM. magnetic particles (Streptavidin Particles Plus--DM) and a
BD IMAG.TM. Cell Separation Magnet are purchased from BD
Biosciences (San Jose, Calif.). Ten ml plastic whole blood tubes
spray-coated with K2EDTA (Cat. No. 366643) are also purchased from
BD.
[0212] For separation and analysis of CTCs, ten mL blood samples
are drawn from patients with lung cancer and stored in K2EDTA
tubes. Mononuclear cells are obtained by density gradient
centrifugation using Ficoll-Hypaque solution. Protocols for
positive selection of CTCs from Ficoll-Hypaque are as disclosed in
BD Technical Data Sheet Streptavidin Particles Plus--DM Material
Number: 557812. After the final wash step on the BD IMAG.TM.
magnet, the released cells are resuspended in buffer.
[0213] The cells are stained with fluorescently labeled
anti-cytokeratin, fluorescently labeled affinity purified goat
anti-TROP-2, DAPI and/or anti-CD45. Subsequent immunofluorescence
images are taken of the captured cells, followed by comprehensive
computer aided analysis based on fluorescence intensities and cell
morphology.
Example 10
Detection of Trop-2.sup.+ CTCs and Treatment of Metastatic Trop-2
Expressing Cancer
[0214] A CELLSEARCH.RTM. system and Circulating Tumor Cell Kit are
obtained Veridex LLC (Raritan, N.J.). A 7.5 ml blood sample is
collected from a 65 year-old male with suspected NSCLC and stored
in a CellSave tube (Veridex LLC). The anti-Trop-2 hRS7 antibody is
substituted for the anti-EpCAM antibody provided with the
CELLSEARCH.RTM. kit. The blood sample is mixed with magnetic
nanoparticles conjugated to anti-Trop-2 antibody. Cells are stained
with fluorescently labeled anti-CD45 and anti-CK antibodies and
cell nuclei are fluorescently labeled with DAPI nuclear dye. A
strong magnetic field is generated in the CELLSEARCH.RTM. system
and used to separate cells bound to the magnetic nanoparticles,
which are then analyzed by FISH to determine Trop-2 copy number, as
described in Example 7 above. The results show the presence of
circulating Trop-2.sup.+ tumor cells, with 4 copies of Trop-2 per
cell. The presence of high copy numbers of Trop-2 in the CTCs
indicates that the patient is a good candidate for therapy with
anti-Trop-2 antibodies.
[0215] Further clinical workup shows the presence of stage IIIB
NSCLC (squamous cell carcinoma). Initial treatment of
caboplatin/etoposide (3 mo) in concert with 7000 cGy XRT results in
a response lasting 10 mo. The patient is then started on Tarceva
maintenance therapy, which he continues until he was considered for
IMMU-132 (hRS7-CL2A-SN-38) trial, in addition to undergoing a
lumbar laminectomy. He receives the first dose of IMMU-132 after 5
months of Tarceva, presenting at the time with a 5.6-cm lesion in
the right lung with abundant pleural effusion. He completes his
6.sup.th dose two months later when the first CT shows the primary
target lesion reduced to 3.2 cm. Periodic assays for Trop-2.sup.+
CTCs show a substantial reduction in CTC number following treatment
with IMMU-132.
[0216] This Example shows the feasibility of selecting for patients
who are responsive to therapy with IMMU-132 or another therapeutic
anti-Trop-2 antibody, by assaying for Trop-2.sup.+ CTCs in the
individual patient's blood and/or determining Trop-2 copy number in
CTCs. The Example further demonstrates the feasibility of
monitoring relative levels of Trop-2.sup.+ CTCs as an indicator of
the efficacy of anti-Trop-2 based therapies. Preferably, patients
who show a positive response, including but not limited to a
complete response (CR), partial response (PR) and/or stable disease
(SD) will show a decrease in levels of Trop-2.sup.+ CTCs of at
least 50%, at least 60%, at least 70%, at least 80%, at least 90%,
at least 95%, at least 98% or at least 99%. Where the treatment is
highly efficacious and results in complete response, a decrease of
100% in Trop-2.sup.+ CTCs may be observed.
Example 11
Isolation and Detection of Trop-2.sup.+ CTCs with a VerIFAST
System
[0217] A VerIFAST system as disclosed in Casavant et al. (2013, Lab
Chip 13:391-6; 2014, Lab Chip 14:99-105) is used to detect Trop-2+
CTCs in TNBC. 7.5 ml blood samples are collected from a series of
patients with suspected TNBC or control normal individuals and
stored in CellSave tubes (Veridex LLC). Biotinylated anti-Trop-2
hRS7 antibody is prepared as disclosed in Casavant et al. (2013,
Lab Chip 13:391-6). The blood samples are mixed with biotinylated
anti-Trop-2 antibody and streptavidin-conjugated PMPs (Casavant et
al., 2013, Lab Chip 13:391-6) and CTCs are separated with the
VerIFAST platform and a handheld magnet. Cells are stained for
tumor markers and cell nuclei are fluorescently labeled with DAPI
nuclear dye. The results show the presence of circulating
Trop-2.sup.+ tumor cells in blood samples from individuals with
TNBC, but not control normal individuals.
Example 12
Clinical Trials with IMMU-132 Anti-Trop-2 ADC Comprising hRS7
Antibody Conjugated to SN-38
[0218] Summary
[0219] The present Example reports results from a phase I clinical
trial and ongoing phase II extension with IMMU-132 (sacituzumab
govitecan), an antibody-drug conjugate (ADC) of the internalizing,
humanized, hRS7 anti-Trop-2 antibody conjugated by a pH-sensitive
linker to SN-38 (mean drug-antibody ratio=7.6). Trop-2 is a type I
transmembrane, calcium-transducing, protein expressed at high
density (.about.1.times.10.sup.5), frequency, and specificity by
many human carcinomas, with limited normal tissue expression.
Preclinical studies in nude mice bearing Capan-1 human pancreatic
tumor xenografts have revealed IMMU-132 is capable of delivering as
much as 136-fold more SN-38 to tumor than derived from a maximally
tolerated irinotecan therapy (not shown).
[0220] The present Example reports the initial Phase I trial of 25
patients (pts) who had failed multiple prior therapies (some
including topoisomerase-I/II inhibiting drugs), and the ongoing
Phase II extension now reporting on 69 pts, including in colorectal
(CRC), small-cell and non-small cell lung (SCLC, NSCLC,
respectively), triple-negative breast (TNBC), pancreatic (PDC),
esophageal, and other cancers.
[0221] As discussed in detail below, Trop-2 was not detected in
serum, but was strongly expressed (.gtoreq.2.sup.+) in most
archived tumors. In a 3+3 trial design, IMMU-132 was given on days
1 and 8 in repeated 21-day cycles, starting at 8 mg/kg/dose, then
12 and 18 mg/kg before dose-limiting neutropenia. To optimize
cumulative treatment with minimal delays, phase II is focusing on 8
and 10 mg/kg (n=30 and 14, respectively). In 49 pts reporting
related AE at this time, neutropenia .gtoreq.G3 occurred in 28% (4%
G4). Most common non-hematological toxicities initially in these
pts have been fatigue (55%; .gtoreq.G3=9%), nausea (53%;
.gtoreq.G3=0%), diarrhea (47%; .gtoreq.G3=9%), alopecia (40%), and
vomiting (32%; .gtoreq.G3=2%). Homozygous UGT1A1 *28/*28 was found
in 6 pts, 2 of whom had more severe hematological and GI
toxicities. In the Phase I and the expansion phases, there are now
48 pts (excluding PDC) who are assessable by RECIST/CT for best
response. Seven (15%) of the patients had a partial response (PR),
including patients with CRC (N=1), TNBC (N=2), SCLC (N=2), NSCLC
(N=1), and esophageal cancers (N=1), and another 27 pts (56%) had
stable disease (SD), for a total of 38 pts (79%) with disease
response; 8 of 13 CT-assessable PDC pts (62%) had SD, with a median
time to progression (TTP) of 12.7 wks compared to 8.0 weeks in
their last prior therapy. The TTP for the remaining 48 pts is 12.6+
wks (range 6.0 to 51.4 wks). Plasma CEA and CA19-9 correlated with
responses. No anti-hRS7 or anti-SN-38 antibodies were detected
despite dosing over months. The conjugate cleared from the serum
within 3 days, consistent with in vivo animal studies where 50% of
the SN-38 was released daily, with >95% of the SN-38 in the
serum being bound to the IgG in a non-glucoronidated form, and at
concentrations as much as 100-fold higher than SN-38 reported in
patients given irinotecan. These results show that the
hRS7-SN-38-containing ADC is therapeutically active in metastatic
solid cancers, with manageable diarrhea and neutropenia.
[0222] Pharmacokinetics
[0223] Two ELISA methods were used to measure the clearance of the
IgG (capture with anti-hRS7 idiotype antibody) and the intact
conjugate (capture with anti-SN-38 IgG/probe with anti-hRS7
idiotype antibody). SN-38 was measured by HPLC. Total IMMU-132
fraction (intact conjugate) cleared more quickly than the IgG (not
shown), reflecting known gradual release of SN-38 from the
conjugate. HPLC determination of SN-38 (Unbound and TOTAL) showed
>95% the SN-38 in the serum was bound to the IgG. Low
concentrations of SN-38G suggest SN-38 bound to the IgG is
protected from glucoronidation. Comparison of ELISA for conjugate
and SN-38 HPLC revealed both overlap, suggesting the ELISA is a
surrogate for monitoring SN-38 clearance.
[0224] A summary of the dosing regiment and patient poll is
provided in Table 6.
TABLE-US-00017 TABLE 6 Clinical Trial Parameters Dosing regimen
Once weekly for 2 weeks administered every 21 days for up to 8
cycles. In the initial enrollment, the planned dose was delayed and
reduced if .gtoreq.G2 treatment-related toxicity; protocol was
amended to dose delay and reduction only in the event of .gtoreq.G3
toxicity. Dose level cohorts 8, 12, 18 mg/kg; later reduced to an
intermediate dose level of 10 mg/kg. Cohort size Standard Phase I
[3 + 3] design; expansion includes 15 patients in select cancers.
DLT G4 ANC .gtoreq.7 d; .gtoreq.G3 febrile neutropenia of any
duration; G4 Plt .gtoreq.5 d; G4 Hgb; Grade 4 N/V/D any duration/G3
N/V/D for >48 h; G3 infusion-related reactions; related
.gtoreq.G3 non-hematological toxicity. Maximum Maximum dose where
.gtoreq. 2/6 patients tolerate 1st 21-d cycle w/o Acceptable Dose
delay or reduction or .gtoreq.G3 toxicity. (MAD) Patients
Metastatic colorectal, pancreas, gastric, esophageal, lung (NSCLC,
SCLC), triple-negative breast (TNBC), prostate, ovarian, renal,
urinary bladder, head/neck, hepatocellular. Refractory/relapsed
after standard treatment regimens for metastatic cancer. Prior
irinotecan- containing therapy NOT required for enrollment. No
bulky lesion >5 cm. Must be 4 weeks beyond any major surgery,
and 2 weeks beyond radiation or chemotherapy regimen. Gilbert's
disease or known CNS metastatic disease are excluded.
[0225] Clinical Trial Status
[0226] A total of 69 patients (including 25 patients in Phase I)
with diverse metastatic cancers having a median of 3 prior
therapies were reported. Eight patients had clinical progression
and withdrew before CT assessment. Thirteen CT-assessable
pancreatic cancer patients were separately reported. The median TTP
(time to progression) in PDC patients was 11.9 wks (range 2 to 21.4
wks) compared to median 8 wks TTP for the preceding last
therapy.
[0227] A total of 48 patients with diverse cancers had at least 1
CT-assessment from which Best Response (not shown) and Time to
Progression (TTP; not shown) were determined. To summarize the Best
Response data, of 8 assessable patients with TNBC (triple-negative
breast cancer), there were 2 PR (partial response), 4 SD (stable
disease) and 2 PD (progressive disease) for a total response
[PR+SD] of 6/8 (75%). For SCLC (small cell lung cancer), of 4
assessable patients there were 2 PR, 0 SD and 2 PD for a total
response of 2/4 (50%). For CRC (colorectal cancer), of 18
assessable patients there were 1 PR, 11 SD and 6 PD for a total
response of 12/18 (67%). For esophageal cancer, of 4 assessable
patients there were 1 PR, 2 SD and 1 PD for a total response of 3/4
(75%). For NSCLC (non-small cell lung cancer), of 5 assessable
patients there were 1 PR, 3 SD and 1 PD for a total response of 4/5
(80%). Over all patients treated, of 48 assessable patients there
were 7 PR, 27 SD and 14 PD for a total response of 34/48 (71%).
These results demonstrate that the anti-TROP-2 ADC (hRS7-SN-38)
showed significant clinical efficacy against a wide range of solid
tumors in human patients.
[0228] The reported side effects of therapy (adverse events) are
summarized in Table 7. The therapeutic efficacy of hRS7-SN-38 was
achieved at dosages of ADC showing an acceptably low level of
adverse side effects. By comparison, patients receiving a dosage of
irinotecan (125 mg/m.sup.2 weekly.times.4, Q6W) showed a much
higher incidence of adverse effects, with 38% incidence of grade
3/4 diarrhea, 31% neutropenia and 8% neutropenic
fever/infection.
TABLE-US-00018 TABLE 7 Related Adverse Events Listing for IMMU-132,
Startingdoes of 8 or 10 mg/kg Criteria: Grade 3-4 Adverse Event for
>5% or any Grade 3 or 4 Adverse Event (N = 123 patients) Grade 3
Grade 4 Neutropenia 22 (18%) 7 (6%) Febrile Neutropenia 3 (2%) 2
(2%) Diarrhea 4 (3%) 0 Anemia 7 (6%) 0 Fatigue 6 (5%) 0 Vomiting 2
(2%) 0 WBC Decrease 2 (2%) 0 Lymphocyte Decrease 2 (2%) 0 Asthenia
1 (1%) 0 Dizziness 1 (1%) 0 Urinary Tract Infection 1 (1%) 0
Alopecia -- --
[0229] Data on dose reduction is also summarized. Of 76 patients
starting at a dose of 8 mg/kg, 12 (16%) were provided with a dose
reduction. Of 33 patients at a starting dose of 10 mg/kg, 5 (15%)
were provided with a dose reduction. Of 9 patients at a starting
dose of 12 mg/kg, 6 (67%) were provided with a dose reduction. Of 3
patients at a starting dose of 18 mg/kg, 3 (100%) were provided
with a dose reduction. We conclude that at 8 and 10 mg/kg, there
were few dose reductions, reflecting a mild, predictable and
manageable toxicity profile at therapeutic levels of ADC.
Currently, 425 serum samples from 148 patients have been analyzed
and no evidence of an antibody response to IMMU-132 has been
detected, even after repeated administration, with some patients
receiving more than 20 doses of ADC.
[0230] Of 46 assessable patients with TNBC treated to date (Phase I
and II), an objective response was seen in 12 patients (26%), with
disease control in 34 patients (74%), a clinical benefit ratio
(CR+PR+(SD.gtoreq.6 mo)] of 46% and a clinical benefit ratio
(CR+PR+(SD.gtoreq.4 mo)] of 63%.
[0231] Of 19 assessable patients with NSCLC treated to date, an
objective response was seen in 6 patients (32%), with disease
control in 14 patients (74%), and a clinical benefit ratio
(CR+PR+(SD.gtoreq.4 mo)] of 59%.
[0232] Of 20 assessable patients with SCLC treated to date, an
objective response was seen in 6 patients (30%), with disease
control in 11 patients (55%), a clinical benefit ratio
(CR+PR+(SD.gtoreq.6 mo)] of 37% and a clinical benefit ratio
(CR+PR+(SD.gtoreq.4 mo)] of 55%.
[0233] Of 16 assessable patients with EAC treated to date, an
objective response was seen in 2 patients (13%), with disease
control in 9 patients (56%), and a clinical benefit ratio
(CR+PR+(SD.gtoreq.4 mo)] of 44%.
[0234] Exemplary partial responses to the anti-Trop-2 ADC were
confirmed by CT data (not shown). As an exemplary PR in CRC, a
62-year-old woman first diagnosed with CRC underwent a primary
hemicolectomy. Four months later, she had a hepatic resection for
liver metastases and received 7 mos of treatment with FOLFOX and 1
mo 5FU. She presented with multiple lesions primarily in the liver
(3+ Trop-2 by immunohistology), entering the hRS7-SN-38 trial at a
starting dose of 8 mg/kg about 1 year after initial diagnosis. On
her first CT assessment, a PR was achieved, with a 37% reduction in
target lesions (not shown). The patient continued treatment,
achieving a maximum reduction of 65% decrease after 10 months of
treatment (not shown) with decrease in CEA from 781 ng/mL to 26.5
ng/mL), before progressing 3 months later.
[0235] As an exemplary PR in NSCLC, a 65-year-old male was
diagnosed with stage IIIB NSCLC (sq. cell). Initial treatment of
caboplatin/etoposide (3 mo) in concert with 7000 cGy XRT resulted
in a response lasting 10 mo. He was then started on Tarceva
maintenance therapy, which he continued until he was considered for
IMMU-132 trial, in addition to undergoing a lumbar laminectomy. He
received first dose of IMMU-132 after 5 months of Tarceva,
presenting at the time with a 5.6 cm lesion in the right lung with
abundant pleural effusion. He had just completed his 6.sup.th dose
two months later when the first CT showed the primary target lesion
reduced to 3.2 cm (not shown).
[0236] As an exemplary PR in SCLC, a 65-year-old woman was
diagnosed with poorly differentiated SCLC. After receiving
carboplatin/etoposide (Topo-II inhibitor) that ended after 2 months
with no response, followed with topotecan (Topo-I inhibitor) that
ended after 2 months, also with no response, she received local XRT
(3000 cGy) that ended 1 month later. However, by the following
month progression had continued. The patient started with IMMU-132
the next month (12 mg/kg; reduced to 6.8 mg/kg; Trop-2 expression
3+), and after two months of IMMU-132, a 38% reduction in target
lesions, including a substantial reduction in the main lung lesion
occurred (not shown). The patient progressed 3 months later after
receiving 12 doses.
[0237] These results are significant in that they demonstrate that
the anti-Trop-2 ADC was efficacious, even in patients who had
failed or progressed after multiple previous therapies.
[0238] In conclusion, at the dosages used, the primary toxicity was
a manageable neutropenia, with few Grade 3 toxicities. IMMU-132
showed evidence of activity (PR and durable SD) in
relapsed/refractory patients with triple-negative breast cancer,
small cell lung cancer, non-small cell lung cancer, colorectal
cancer and esophageal cancer, including patients with a previous
history of relapsing on topoisomerase-I inhibitor therapy. These
results show efficacy of the anti-Trop-2 ADC in a wide range of
cancers that are resistant to existing therapies.
[0239] It will be apparent to those skilled in the art that various
modifications and variations can be made to the products,
compositions, methods and processes of this invention. Thus, it is
intended that the present invention cover such modifications and
variations, provided they come within the scope of the appended
claims and their equivalents.
Sequence CWU 1
1
96111PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 1Lys Ala Ser Gln Asp Val Ser Ile Ala Val Ala1 5
1027PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 2Ser Ala Ser Tyr Arg Tyr Thr1 539PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 3Gln
Gln His Tyr Ile Thr Pro Leu Thr1 545PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 4Asn
Tyr Gly Met Asn1 5517PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 5Trp Ile Asn Thr Tyr Thr Gly
Glu Pro Thr Tyr Thr Asp Asp Phe Lys1 5 10 15Gly612PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 6Gly
Gly Phe Gly Ser Ser Tyr Trp Tyr Phe Asp Val1 5 107330PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
7Ala Ser Thr Lys Gly Pro Ser Val Phe Pro Leu Ala Pro Ser Ser Lys1 5
10 15Ser Thr Ser Gly Gly Thr Ala Ala Leu Gly Cys Leu Val Lys Asp
Tyr 20 25 30Phe Pro Glu Pro Val Thr Val Ser Trp Asn Ser Gly Ala Leu
Thr Ser 35 40 45Gly Val His Thr Phe Pro Ala Val Leu Gln Ser Ser Gly
Leu Tyr Ser 50 55 60Leu Ser Ser Val Val Thr Val Pro Ser Ser Ser Leu
Gly Thr Gln Thr65 70 75 80Tyr Ile Cys Asn Val Asn His Lys Pro Ser
Asn Thr Lys Val Asp Lys 85 90 95Lys Ala Glu Pro Lys Ser Cys Asp Lys
Thr His Thr Cys Pro Pro Cys 100 105 110Pro Ala Pro Glu Leu Leu Gly
Gly Pro Ser Val Phe Leu Phe Pro Pro 115 120 125Lys Pro Lys Asp Thr
Leu Met Ile Ser Arg Thr Pro Glu Val Thr Cys 130 135 140Val Val Val
Asp Val Ser His Glu Asp Pro Glu Val Lys Phe Asn Trp145 150 155
160Tyr Val Asp Gly Val Glu Val His Asn Ala Lys Thr Lys Pro Arg Glu
165 170 175Glu Gln Tyr Asn Ser Thr Tyr Arg Val Val Ser Val Leu Thr
Val Leu 180 185 190His Gln Asp Trp Leu Asn Gly Lys Glu Tyr Lys Cys
Lys Val Ser Asn 195 200 205Lys Ala Leu Pro Ala Pro Ile Glu Lys Thr
Ile Ser Lys Ala Lys Gly 210 215 220Gln Pro Arg Glu Pro Gln Val Tyr
Thr Leu Pro Pro Ser Arg Asp Glu225 230 235 240Leu Thr Lys Asn Gln
Val Ser Leu Thr Cys Leu Val Lys Gly Phe Tyr 245 250 255Pro Ser Asp
Ile Ala Val Glu Trp Glu Ser Asn Gly Gln Pro Glu Asn 260 265 270Asn
Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser Asp Gly Ser Phe Phe 275 280
285Leu Tyr Ser Lys Leu Thr Val Asp Lys Ser Arg Trp Gln Gln Gly Asn
290 295 300Val Phe Ser Cys Ser Val Met His Glu Ala Leu His Asn His
Tyr Thr305 310 315 320Gln Lys Ser Leu Ser Leu Ser Pro Gly Lys 325
3308330PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 8Ala Ser Thr Lys Gly Pro Ser Val Phe Pro Leu
Ala Pro Ser Ser Lys1 5 10 15Ser Thr Ser Gly Gly Thr Ala Ala Leu Gly
Cys Leu Val Lys Asp Tyr 20 25 30Phe Pro Glu Pro Val Thr Val Ser Trp
Asn Ser Gly Ala Leu Thr Ser 35 40 45Gly Val His Thr Phe Pro Ala Val
Leu Gln Ser Ser Gly Leu Tyr Ser 50 55 60Leu Ser Ser Val Val Thr Val
Pro Ser Ser Ser Leu Gly Thr Gln Thr65 70 75 80Tyr Ile Cys Asn Val
Asn His Lys Pro Ser Asn Thr Lys Val Asp Lys 85 90 95Arg Val Glu Pro
Lys Ser Cys Asp Lys Thr His Thr Cys Pro Pro Cys 100 105 110Pro Ala
Pro Glu Leu Leu Gly Gly Pro Ser Val Phe Leu Phe Pro Pro 115 120
125Lys Pro Lys Asp Thr Leu Met Ile Ser Arg Thr Pro Glu Val Thr Cys
130 135 140Val Val Val Asp Val Ser His Glu Asp Pro Glu Val Lys Phe
Asn Trp145 150 155 160Tyr Val Asp Gly Val Glu Val His Asn Ala Lys
Thr Lys Pro Arg Glu 165 170 175Glu Gln Tyr Asn Ser Thr Tyr Arg Val
Val Ser Val Leu Thr Val Leu 180 185 190His Gln Asp Trp Leu Asn Gly
Lys Glu Tyr Lys Cys Lys Val Ser Asn 195 200 205Lys Ala Leu Pro Ala
Pro Ile Glu Lys Thr Ile Ser Lys Ala Lys Gly 210 215 220Gln Pro Arg
Glu Pro Gln Val Tyr Thr Leu Pro Pro Ser Arg Glu Glu225 230 235
240Met Thr Lys Asn Gln Val Ser Leu Thr Cys Leu Val Lys Gly Phe Tyr
245 250 255Pro Ser Asp Ile Ala Val Glu Trp Glu Ser Asn Gly Gln Pro
Glu Asn 260 265 270Asn Tyr Lys Thr Thr Pro Pro Val Leu Asp Ser Asp
Gly Ser Phe Phe 275 280 285Leu Tyr Ser Lys Leu Thr Val Asp Lys Ser
Arg Trp Gln Gln Gly Asn 290 295 300Val Phe Ser Cys Ser Val Met His
Glu Ala Leu His Asn His Tyr Thr305 310 315 320Gln Lys Ser Leu Ser
Leu Ser Pro Gly Lys 325 330944PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 9Ser His Ile Gln Ile Pro
Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu
Arg Gln Gln Pro Pro Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe
Thr Arg Leu Arg Glu Ala Arg Ala 35 401045PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
10Cys Gly His Ile Gln Ile Pro Pro Gly Leu Thr Glu Leu Leu Gln Gly1
5 10 15Tyr Thr Val Glu Val Leu Arg Gln Gln Pro Pro Asp Leu Val Glu
Phe 20 25 30Ala Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
40 451117PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 11Gln Ile Glu Tyr Leu Ala Lys Gln Ile Val Asp Asn
Ala Ile Gln Gln1 5 10 15Ala1221PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 12Cys Gly Gln Ile Glu Tyr Leu
Ala Lys Gln Ile Val Asp Asn Ala Ile1 5 10 15Gln Gln Ala Gly Cys
201350PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 13Ser Leu Arg Glu Cys Glu Leu Tyr Val Gln Lys
His Asn Ile Gln Ala1 5 10 15Leu Leu Lys Asp Ser Ile Val Gln Leu Cys
Thr Ala Arg Pro Glu Arg 20 25 30Pro Met Ala Phe Leu Arg Glu Tyr Phe
Glu Arg Leu Glu Lys Glu Glu 35 40 45Ala Lys 501455PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
14Met Ser Cys Gly Gly Ser Leu Arg Glu Cys Glu Leu Tyr Val Gln Lys1
5 10 15His Asn Ile Gln Ala Leu Leu Lys Asp Ser Ile Val Gln Leu Cys
Thr 20 25 30Ala Arg Pro Glu Arg Pro Met Ala Phe Leu Arg Glu Tyr Phe
Glu Arg 35 40 45Leu Glu Lys Glu Glu Ala Lys 50 551523PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 15Cys
Gly Phe Glu Glu Leu Ala Trp Lys Ile Ala Lys Met Ile Trp Ser1 5 10
15Asp Val Phe Gln Gln Gly Cys 201651PRTHomo sapiens 16Ser Leu Arg
Glu Cys Glu Leu Tyr Val Gln Lys His Asn Ile Gln Ala1 5 10 15Leu Leu
Lys Asp Val Ser Ile Val Gln Leu Cys Thr Ala Arg Pro Glu 20 25 30Arg
Pro Met Ala Phe Leu Arg Glu Tyr Phe Glu Lys Leu Glu Lys Glu 35 40
45Glu Ala Lys 501754PRTHomo sapiens 17Ser Leu Lys Gly Cys Glu Leu
Tyr Val Gln Leu His Gly Ile Gln Gln1 5 10 15Val Leu Lys Asp Cys Ile
Val His Leu Cys Ile Ser Lys Pro Glu Arg 20 25 30Pro Met Lys Phe Leu
Arg Glu His Phe Glu Lys Leu Glu Lys Glu Glu 35 40 45Asn Arg Gln Ile
Leu Ala 501844PRTHomo sapiens 18Ser His Ile Gln Ile Pro Pro Gly Leu
Thr Glu Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Gly Gln Gln Pro
Pro Asp Leu Val Asp Phe Ala Val 20 25 30Glu Tyr Phe Thr Arg Leu Arg
Glu Ala Arg Arg Gln 35 401944PRTHomo sapiens 19Ser Ile Glu Ile Pro
Ala Gly Leu Thr Glu Leu Leu Gln Gly Phe Thr1 5 10 15Val Glu Val Leu
Arg His Gln Pro Ala Asp Leu Leu Glu Phe Ala Leu 20 25 30Gln His Phe
Thr Arg Leu Gln Gln Glu Asn Glu Arg 35 402044PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
20Thr His Ile Gln Ile Pro Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1
5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro Asp Leu Val Glu Phe
Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
402144PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 21Ser Lys Ile Gln Ile Pro Pro Gly Leu Thr Glu
Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro
Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu
Ala Arg Ala 35 402244PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 22Ser Arg Ile Gln Ile Pro
Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu
Arg Gln Gln Pro Pro Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe
Thr Arg Leu Arg Glu Ala Arg Ala 35 402344PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
23Ser His Ile Asn Ile Pro Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1
5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro Asp Leu Val Glu Phe
Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
402444PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 24Ser His Ile Gln Ile Pro Pro Ala Leu Thr Glu
Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro
Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu
Ala Arg Ala 35 402544PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 25Ser His Ile Gln Ile Pro
Pro Gly Leu Ser Glu Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu
Arg Gln Gln Pro Pro Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe
Thr Arg Leu Arg Glu Ala Arg Ala 35 402644PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
26Ser His Ile Gln Ile Pro Pro Gly Leu Thr Asp Leu Leu Gln Gly Tyr1
5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro Asp Leu Val Glu Phe
Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
402744PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 27Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu
Leu Leu Asn Gly Tyr1 5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro
Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu
Ala Arg Ala 35 402844PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 28Ser His Ile Gln Ile Pro
Pro Gly Leu Thr Glu Leu Leu Gln Ala Tyr1 5 10 15Thr Val Glu Val Leu
Arg Gln Gln Pro Pro Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe
Thr Arg Leu Arg Glu Ala Arg Ala 35 402944PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
29Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1
5 10 15Ser Val Glu Val Leu Arg Gln Gln Pro Pro Asp Leu Val Glu Phe
Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
403044PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 30Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu
Leu Leu Gln Gly Tyr1 5 10 15Thr Val Asp Val Leu Arg Gln Gln Pro Pro
Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu
Ala Arg Ala 35 403144PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 31Ser His Ile Gln Ile Pro
Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu
Lys Gln Gln Pro Pro Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe
Thr Arg Leu Arg Glu Ala Arg Ala 35 403244PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
32Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1
5 10 15Thr Val Glu Val Leu Arg Asn Gln Pro Pro Asp Leu Val Glu Phe
Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
403344PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 33Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu
Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu Arg Gln Asn Pro Pro
Asp Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu
Ala Arg Ala 35 403444PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 34Ser His Ile Gln Ile Pro
Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu
Arg Gln Gln Pro Pro Glu Leu Val Glu Phe Ala 20 25 30Val Glu Tyr Phe
Thr Arg Leu Arg Glu Ala Arg Ala 35 403544PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
35Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1
5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro Asp Leu Val Asp Phe
Ala 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
403644PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 36Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu
Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro
Asp Leu Val Glu Phe Leu 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu
Ala Arg Ala 35 403744PRTArtificial SequenceDescription of
Artificial Sequence Synthetic polypeptide 37Ser His Ile Gln Ile Pro
Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu
Arg Gln Gln Pro Pro Asp Leu Val Glu Phe Ile 20 25 30Val Glu Tyr Phe
Thr Arg Leu Arg Glu Ala Arg Ala 35 403844PRTArtificial
SequenceDescription of Artificial Sequence Synthetic polypeptide
38Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu Leu Leu Gln Gly Tyr1
5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro Asp Leu Val Glu Phe
Val 20 25 30Val Glu Tyr Phe Thr Arg Leu Arg Glu Ala Arg Ala 35
403944PRTArtificial SequenceDescription of Artificial Sequence
Synthetic polypeptide 39Ser His Ile Gln Ile Pro Pro Gly Leu Thr Glu
Leu Leu Gln Gly Tyr1 5 10 15Thr Val Glu Val Leu Arg Gln Gln Pro Pro
Asp Leu Val Glu Phe Ala 20 25 30Val Asp Tyr Phe Thr Arg Leu Arg Glu
Ala Arg Ala 35 404017PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 40Asn
Ile Glu Tyr Leu Ala Lys Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10
15Ala4117PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 41Gln Leu Glu Tyr Leu Ala Lys Gln Ile Val Asp Asn
Ala Ile Gln Gln1 5 10 15Ala4217PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 42Gln Val Glu Tyr Leu Ala Lys
Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10 15Ala4317PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 43Gln
Ile Asp Tyr Leu Ala Lys Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10
15Ala4417PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 44Gln Ile Glu Phe Leu Ala Lys Gln Ile Val Asp Asn
Ala Ile Gln Gln1 5 10 15Ala4517PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 45Gln Ile Glu Thr Leu Ala Lys
Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10 15Ala4617PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 46Gln
Ile Glu Ser Leu Ala Lys Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10
15Ala4717PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 47Gln Ile Glu Tyr Ile Ala Lys Gln Ile Val Asp Asn
Ala Ile Gln Gln1 5 10 15Ala4817PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 48Gln Ile Glu Tyr Val Ala Lys
Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10 15Ala4917PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 49Gln
Ile Glu Tyr Leu Ala Arg Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10
15Ala5017PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 50Gln Ile Glu Tyr Leu Ala Lys Asn Ile Val Asp Asn
Ala Ile Gln Gln1 5 10 15Ala5117PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 51Gln Ile Glu Tyr Leu Ala Lys
Gln Ile Val Glu Asn Ala Ile Gln Gln1 5 10 15Ala5217PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 52Gln
Ile Glu Tyr Leu Ala Lys Gln Ile Val Asp Gln Ala Ile Gln Gln1 5 10
15Ala5317PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 53Gln Ile Glu Tyr Leu Ala Lys Gln Ile Val Asp Asn
Ala Ile Asn Gln1 5 10 15Ala5417PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 54Gln Ile Glu Tyr Leu Ala Lys
Gln Ile Val Asp Asn Ala Ile Gln Asn1 5 10 15Ala5517PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 55Gln
Ile Glu Tyr Leu Ala Lys Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10
15Leu5617PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 56Gln Ile Glu Tyr Leu Ala Lys Gln Ile Val Asp Asn
Ala Ile Gln Gln1 5 10 15Ile5717PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 57Gln Ile Glu Tyr Leu Ala Lys
Gln Ile Val Asp Asn Ala Ile Gln Gln1 5 10 15Val5817PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 58Gln
Ile Glu Tyr Val Ala Lys Gln Ile Val Asp Tyr Ala Ile His Gln1 5 10
15Ala5917PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 59Gln Ile Glu Tyr Lys Ala Lys Gln Ile Val Asp His
Ala Ile His Gln1 5 10 15Ala6017PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 60Gln Ile Glu Tyr His Ala Lys
Gln Ile Val Asp His Ala Ile His Gln1 5 10 15Ala6117PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 61Gln
Ile Glu Tyr Val Ala Lys Gln Ile Val Asp His Ala Ile His Gln1 5 10
15Ala6218PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 62Pro Leu Glu Tyr Gln Ala Gly Leu Leu Val Gln Asn
Ala Ile Gln Gln1 5 10 15Ala Ile6318PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 63Leu
Leu Ile Glu Thr Ala Ser Ser Leu Val Lys Asn Ala Ile Gln Leu1 5 10
15Ser Ile6418PRTArtificial SequenceDescription of Artificial
Sequence Synthetic peptide 64Leu Ile Glu Glu Ala Ala Ser Arg Ile
Val Asp Ala Val Ile Glu Gln1 5 10 15Val Lys6518PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 65Ala
Leu Tyr Gln Phe Ala Asp Arg Phe Ser Glu Leu Val Ile Ser Glu1 5 10
15Ala Leu6617PRTArtificial SequenceDescription of Artificial
Sequence Synthetic peptide 66Leu Glu Gln Val Ala Asn Gln Leu Ala
Asp Gln Ile Ile Lys Glu Ala1 5 10 15Thr6717PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 67Phe
Glu Glu Leu Ala Trp Lys Ile Ala Lys Met Ile Trp Ser Asp Val1 5 10
15Phe6818PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 68Glu Leu Val Arg Leu Ser Lys Arg Leu Val Glu Asn
Ala Val Leu Lys1 5 10 15Ala Val6918PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 69Thr
Ala Glu Glu Val Ser Ala Arg Ile Val Gln Val Val Thr Ala Glu1 5 10
15Ala Val7018PRTArtificial SequenceDescription of Artificial
Sequence Synthetic peptide 70Gln Ile Lys Gln Ala Ala Phe Gln Leu
Ile Ser Gln Val Ile Leu Glu1 5 10 15Ala Thr7116PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 71Leu
Ala Trp Lys Ile Ala Lys Met Ile Val Ser Asp Val Met Gln Gln1 5 10
157224PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 72Asp Leu Ile Glu Glu Ala Ala Ser Arg Ile Val Asp
Ala Val Ile Glu1 5 10 15Gln Val Lys Ala Ala Gly Ala Tyr
207318PRTArtificial SequenceDescription of Artificial Sequence
Synthetic peptide 73Leu Glu Gln Tyr Ala Asn Gln Leu Ala Asp Gln Ile
Ile Lys Glu Ala1 5 10 15Thr Glu7420PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 74Phe
Glu Glu Leu Ala Trp Lys Ile Ala Lys Met Ile Trp Ser Asp Val1 5 10
15Phe Gln Gln Cys 207517PRTArtificial SequenceDescription of
Artificial Sequence Synthetic peptide 75Gln Ile Glu Tyr Leu Ala Lys
Gln Ile Pro Asp Asn Ala Ile Gln Gln1 5 10 15Ala7625PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 76Lys
Gly Ala Asp Leu Ile Glu Glu Ala Ala Ser Arg Ile Val Asp Ala1 5 10
15Val Ile Glu Gln Val Lys Ala Ala Gly 20 257725PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 77Lys
Gly Ala Asp Leu Ile Glu Glu Ala Ala Ser Arg Ile Pro Asp Ala1 5 10
15Pro Ile Glu Gln Val Lys Ala Ala Gly 20 257825PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 78Pro
Glu Asp Ala Glu Leu Val Arg Leu Ser Lys Arg Leu Val Glu Asn1 5 10
15Ala Val Leu Lys Ala Val Gln Gln Tyr 20 257925PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 79Pro
Glu Asp Ala Glu Leu Val Arg Thr Ser Lys Arg Leu Val Glu Asn1 5 10
15Ala Val Leu Lys Ala Val Gln Gln Tyr 20 258025PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 80Pro
Glu Asp Ala Glu Leu Val Arg Leu Ser Lys Arg Asp Val Glu Asn1 5 10
15Ala Val Leu Lys Ala Val Gln Gln Tyr 20 258125PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 81Pro
Glu Asp Ala Glu Leu Val Arg Leu Ser Lys Arg Leu Pro Glu Asn1 5 10
15Ala Val Leu Lys Ala Val Gln Gln Tyr 20 258225PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 82Pro
Glu Asp Ala Glu Leu Val Arg Leu Ser Lys Arg Leu Pro Glu Asn1 5 10
15Ala Pro Leu Lys Ala Val Gln Gln Tyr 20 258325PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 83Pro
Glu Asp Ala Glu Leu Val Arg Leu Ser Lys Arg Leu Val Glu Asn1 5 10
15Ala Val Glu Lys Ala Val Gln Gln Tyr 20 258425PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 84Glu
Glu Gly Leu Asp Arg Asn Glu Glu Ile Lys Arg Ala Ala Phe Gln1 5 10
15Ile Ile Ser Gln Val Ile Ser Glu Ala 20 258525PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 85Leu
Val Asp Asp Pro Leu Glu Tyr Gln Ala Gly Leu Leu Val Gln Asn1 5 10
15Ala Ile Gln Gln Ala Ile Ala Glu Gln 20 258625PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 86Gln
Tyr Glu Thr Leu Leu Ile Glu Thr Ala Ser Ser Leu Val Lys Asn1 5 10
15Ala Ile Gln Leu Ser Ile Glu Gln Leu 20 258725PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 87Leu
Glu Lys Gln Tyr Gln Glu Gln Leu Glu Glu Glu Val Ala Lys Val1 5 10
15Ile Val Ser Met Ser Ile Ala Phe Ala 20 258825PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 88Asn
Thr Asp Glu Ala Gln Glu Glu Leu Ala Trp Lys Ile Ala Lys Met1 5 10
15Ile Val Ser Asp Ile Met Gln Gln Ala 20 258925PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 89Val
Asn Leu Asp Lys Lys Ala Val Leu Ala Glu Lys Ile Val Ala Glu1 5 10
15Ala Ile Glu Lys Ala Glu Arg Glu Leu 20 259025PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 90Asn
Gly Ile Leu Glu Leu Glu Thr Lys Ser Ser Lys Leu Val Gln Asn1 5 10
15Ile Ile Gln Thr Ala Val Asp Gln Phe 20 259125PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 91Thr
Gln Asp Lys Asn Tyr Glu Asp Glu Leu Thr Gln Val Ala Leu Ala1 5 10
15Leu Val Glu Asp Val Ile Asn Tyr Ala 20 259225PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 92Glu
Thr Ser Ala Lys Asp Asn Ile Asn Ile Glu Glu Ala Ala Arg Phe1 5 10
15Leu Val Glu Lys Ile Leu Val Asn His 20 259316PRTArtificial
SequenceDescription of Artificial Sequence Synthetic peptide 93Glu
Phe Pro Lys Pro Ser Thr Pro Pro Gly Ser Ser Gly Gly Ala Pro1 5 10
159444PRTArtificial SequenceDescription of Artificial Sequence
Synthetic consensus polypeptideMOD_RES(1)..(1)Ser or
ThrMOD_RES(2)..(2)His, Lys or ArgMOD_RES(4)..(4)Gln or
AsnMOD_RES(8)..(8)Gly or AlaMOD_RES(10)..(10)Thr or
SerMOD_RES(11)..(11)Glu or AspMOD_RES(14)..(14)Gln or
AsnMOD_RES(15)..(15)Gly or AlaMOD_RES(17)..(17)Thr or
SerMOD_RES(19)..(19)Glu or AspMOD_RES(22)..(22)Arg or
LysMOD_RES(23)..(24)Asn or GlnMOD_RES(27)..(27)Asp or
GluMOD_RES(30)..(30)Glu or AspMOD_RES(32)..(32)Ala, Leu, Ile or
ValMOD_RES(34)..(34)Glu or AspMOD_RES(37)..(37)Thr or
SerMOD_RES(38)..(38)Arg or LysMOD_RES(40)..(40)Arg or
LysMOD_RES(41)..(41)Glu or AspMOD_RES(42)..(42)Ala, Leu, Ile or
ValMOD_RES(43)..(43)Arg or LysMOD_RES(44)..(44)Ala, Leu, Ile or Val
94Xaa Xaa Ile Xaa Ile Pro Pro Xaa Leu Xaa Xaa Leu Leu Xaa Xaa Tyr1
5 10 15Xaa Val Xaa Val Leu Xaa Xaa Xaa Pro Pro Xaa Leu Val Xaa Phe
Xaa 20 25 30Val Xaa Tyr Phe Xaa Xaa Leu Xaa Xaa Xaa Xaa Xaa 35
409517PRTArtificial SequenceDescription of Artificial Sequence
Synthetic consensus peptideMOD_RES(1)..(1)Gln or
AsnMOD_RES(2)..(2)Ile, Leu or ValMOD_RES(3)..(3)Glu or
AspMOD_RES(4)..(4)Tyr, Phe, Thr or SerMOD_RES(5)..(5)Leu, Ile or
ValMOD_RES(7)..(7)Lys or ArgMOD_RES(8)..(8)Gln or
AsnMOD_RES(11)..(11)Asp or GluMOD_RES(12)..(12)Asn or
GlnMOD_RES(15)..(16)Gln or AsnMOD_RES(17)..(17)Ala, Leu, Ile or Val
95Xaa Xaa Xaa Xaa Xaa Ala Xaa Xaa Ile Val Xaa Xaa Ala Ile Xaa Xaa1
5 10 15Xaa9644PRTArtificial SequenceDescription of Artificial
Sequence Synthetic consensus polypeptideMOD_RES(1)..(1)Ser or
ThrMOD_RES(4)..(4)Gln or AsnMOD_RES(10)..(10)Thr or
SerMOD_RES(18)..(18)Val, Ile, Leu or AlaMOD_RES(23)..(23)Gln or
AsnMOD_RES(33)..(33)Val, Ile, Leu or AlaMOD_RES(34)..(34)Glu or
AspMOD_RES(37)..(37)Thr or SerMOD_RES(38)..(38)Arg or
LysMOD_RES(40)..(40)Arg or LysMOD_RES(42)..(42)Ala, Leu, Ile or
ValMOD_RES(44)..(44)Ala, Leu, Ile or Val 96Xaa His Ile Xaa Ile Pro
Pro Gly Leu Xaa Glu Leu Leu Gln Gly Tyr1 5 10 15Thr Xaa Glu Val Leu
Arg Xaa Gln Pro Pro Asp Leu Val Glu Phe Ala 20 25 30Xaa Xaa Tyr Phe
Xaa Xaa Leu Xaa Glu Xaa Arg Xaa 35 40
* * * * *