U.S. patent application number 11/410442 was filed with the patent office on 2006-10-26 for antibodies with immune effector activity and that internalize in folate receptor alpha-positive cells.
This patent application is currently assigned to Morphotek Inc.. Invention is credited to Luigi Grasso, Nicholas C. Nicolaides, Philip M. Sass.
Application Number | 20060239910 11/410442 |
Document ID | / |
Family ID | 37215502 |
Filed Date | 2006-10-26 |
United States Patent
Application |
20060239910 |
Kind Code |
A1 |
Nicolaides; Nicholas C. ; et
al. |
October 26, 2006 |
Antibodies with immune effector activity and that internalize in
folate receptor alpha-positive cells
Abstract
This invention relates to the use of monoclonal and polyclonal
antibodies that specifically bind to and have the ability in the
alternative to become internalized by cells expressing folate
receptor alpha (FRA) and to induce an immune effector activity such
as antibody-dependent cellular cytotoxicity. The antibodies are
useful in specific delivery of pharmacologic agents to
FRA-expressing cells as well as in eliciting an immune-effector
activity particularly on tumor cells and precursors. The invention
is also related to nucleotides encoding the antibodies of the
invention, cells expressing the antibodies; methods of detecting
cancer cells; and methods of treating cancer using the
antibodies.
Inventors: |
Nicolaides; Nicholas C.;
(Boothwyn, PA) ; Grasso; Luigi; (Bala Cynwyd,
PA) ; Sass; Philip M.; (Audubon, PA) |
Correspondence
Address: |
WOODCOCK WASHBURN LLP
ONE LIBERTY PLACE, 46TH FLOOR
1650 MARKET STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
Morphotek Inc.
|
Family ID: |
37215502 |
Appl. No.: |
11/410442 |
Filed: |
April 24, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60674185 |
Apr 22, 2005 |
|
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|
Current U.S.
Class: |
424/1.49 ;
424/144.1; 435/320.1; 435/334; 435/69.1; 435/7.1; 530/388.22;
530/391.1; 536/23.53 |
Current CPC
Class: |
C07K 2317/24 20130101;
C07K 16/22 20130101; C07K 2317/76 20130101; A61K 31/7068 20130101;
A61K 47/6869 20170801; C07K 2317/732 20130101; A61K 47/6897
20170801; C07K 16/30 20130101; C07K 16/3069 20130101; A61K 47/6825
20170801; A61K 31/704 20130101; A61P 35/00 20180101; C07K 2317/21
20130101; A61K 47/6851 20170801; A61K 39/39558 20130101; C07K 16/28
20130101; B82Y 5/00 20130101; C07K 2317/77 20130101 |
Class at
Publication: |
424/001.49 ;
435/007.1; 424/144.1; 435/069.1; 435/320.1; 435/334; 530/388.22;
530/391.1; 536/023.53 |
International
Class: |
A61K 51/00 20060101
A61K051/00; G01N 33/53 20060101 G01N033/53; C07H 21/04 20060101
C07H021/04; C12P 21/06 20060101 C12P021/06; A61K 39/395 20060101
A61K039/395; C12N 5/06 20060101 C12N005/06; C07K 16/28 20060101
C07K016/28; C07K 16/46 20060101 C07K016/46 |
Claims
1. An in-out anti-folate receptor alpha antibody that (a)
specifically binds to folate receptor alpha (FRA) and (b)
alternatively elicits an immune effector activity or internalizes
within FRA-bearing cells.
2. The antibody of claim 1 wherein said antibody binds FRA with an
affinity of at least about 1.times.10.sup.-7 M.
3. The antibody of claim 1 wherein said antibody binds FRA with an
affinity of at least about 1.times.10.sup.-8 M.
4. The antibody of claim 1 wherein said antibody binds FRA with an
affinity of at least about 1.times.10.sup.-9 M.
5. The antibody of claim 1 wherein said antibody binds FRA with an
affinity of at least about 1.times.10.sup.-10 M.
6. The antibody of claim 1 wherein said antibody is a chimeric
antibody.
7. The antibody of claim 6 wherein said chimeric antibody is a
human-mouse chimeric antibody.
8. The antibody of claim 1 wherein said antibody is a humanized
antibody.
9. The antibody of claim 1 wherein said antibody is a fully human
antibody.
10. The antibody of claim 1 wherein antibody is conjugated to a
chemotherapeutic agent.
11. The antibody of claim 10 wherein said chemotherapeutic agent is
a radionuclide.
12. The antibody of claim 1 wherein FRA comprises an amino acid
sequence of SEQ ID NO:2.
13. The antibody of claim 1 wherein FRA is encoded by the
nucleotide sequence of SEQ ID NO:1.
14. The antibody of claim 1, wherein the immune effector activity
is antibody-dependent cellular cytotoxicity.
15. A polynucleotide encoding a heavy chain of the antibody of
claim 1.
16. A polynucleotide encoding a light chain of the antibody of
claim 1.
17. A polynucleotide encoding a heavy chain and a light chain of
the antibody of claim 1.
18. A pharmaceutical composition comprising the antibody of claim
1.
19. The pharmaceutical composition of claim 18, wherein the
antibody is conjugated to a chemotherapeutic agent.
20. The pharmaceutical composition of claim 19, wherein the
chemotherapeutic agent is a radionuclide.
21. A vector comprising a polynucleotide encoding a heavy chain of
the antibody of claim 1.
22. A vector comprising a polynucleotide encoding a light chain of
the antibody of claim 1.
23. A vector comprising a polynucleotide encoding a heavy chain of
the antibody of claim 1 and a light chain of the antibody of claim
1.
24. An expression cell comprising a polynucleotide encoding a heavy
chain of the antibody of claim 1 and a polynucleotide encoding a
light chain of the antibody of claim 1.
25. An expression cell comprising the vector of claim 23.
26. The expression cell of claim 25, wherein the cell is a
mammalian cell.
27. The expression cell of claim 24 wherein the cell is a mammalian
cell.
28. A cell that produces the antibody of claim 1.
29. The cell of claim 28, wherein the cell is a hybridoma.
30. A method of producing an in-out antibody that specifically
binds to FRA comprising the steps of culturing the cell of claim 28
and recovering the antibody from growth medium.
31. A method of inhibiting the growth of FRA-positive cells
comprising administering to a subject having said cells an in-out
anti-FRA antibody.
32. The method of claim 31 wherein said in-out anti-FRA antibody is
conjugated to a biomolecule.
33. The method of claim 31 wherein the FRA-positive cells are
dysplastic cells.
34. The method of claim 31 wherein the subject is a human.
35. The method of claim 31 wherein said antibody is conjugated to a
chemotherapeutic agent.
36. The method of claim 35 wherein said chemotherapeutic agent is a
radionuclide.
37. The method of claim 31 further comprising administering to said
subject a cytotoxic agent.
38. The method of claim 31 further comprising administering to said
subject a cytostatic agent.
39. The method of claim 31 further comprising administering to said
subject a chemotherapeutic agent.
40. The method of claim 31 wherein the antibody is administered as
an unconjugated antibody.
41. The method of claim 31 wherein the antibody is administered as
a mixture of unconjugated antibody and antibody conjugated to a
chemotherapeutic agent.
42. A kit comprising an antibody that specifically binds to FRA,
wherein the antibody alternatively elicits an immune effector
activity or internalizes within FRA-bearing cells, and instructions
for using the kit in a method for inhibiting the growth of
FRA-bearing cells in a subject.
43. The kit of claim 42 further comprising at least one
chemotherapeutic agent.
44. The kit of claim 42 further comprising at least one diagnostic
agent.
45. The kit of claim 42 further comprising means and instructions
for administering the antibody to the subject.
46. A kit comprising an in-out anti-FRA antibody and instructions
for using the kit in a method for identifying the presence of
FRA-bearing cells in vitro or in vivo.
47. The kit of claim 46 further comprising at least one diagnostic
agent.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This claims benefit of U.S. Provisional Application
60/674,185, filed Apr. 22, 2005, which is incorporated herein by
reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates to the use of monoclonal and
polyclonal antibodies that specifically bind to and alternatively
become internalized by cells expressing or bearing folate receptor
alpha (FRA) ("FRA-positive cells") and induce an immune effector
activity such as antibody dependent cellular cytotoxicity. The
antibodies are useful in specific delivery of pharmacologic agents
to FRA-positive cells as well as in eliciting an immune-effector
activity particularly on tumor and dysplastic cells. The invention
is also related to cells expressing the monoclonal antibodies,
polyclonal antibodies, antibody derivatives, such as chimeric and
humanized monoclonal antibodies, antibody fragments, methods of
detecting FRA-positive cells, and methods of treating cancer using
the antibodies of the invention.
BACKGROUND OF THE INVENTION
[0003] There are three major isoforms of the human membrane folate
binding proteins, .alpha., .beta., and .gamma.. The .alpha. and
.beta. isoforms have about 70% amino acid sequence homology and
differ dramatically in their stereospecificity for some folates.
Both isoforms are expressed in both fetal and adult tissue,
although normal tissue generally expresses low to moderate amounts
of FR-.beta.. FR-.alpha., however, is expressed in a subset of
normal epithelial cells, and is frequently strikingly elevated in a
variety of carcinomas (Ross et al. (1994) Cancer 73(9):2432-2443;
Rettig et al. (1988) Proc. Natl. Acad. Sci. USA 85:3110-3114;
Campbell et al. (1991) Cancer Res. 51:5329-5338; Coney et al.
(1991) Cancer Res. 51:6125-6132; Weitman et al. (1992) Cancer Res.
52:3396-3401; Garin-Chesa et al. (1993) Am. J. Pathol. 142:557-567;
Holm et al. (1994) APMIS 102:413-419; Franklin et al. (1994) Int.
J. Cancer 8 (Suppl.):89-95; Miotti et al. (1987) Int. J. Cancer
39:297-303; and Vegglan et al. (1989) Tumori 75:510-513).
FR-.alpha. is overexpressed in greater than 90% of ovarian
carcinomas (Sudimack and Lee (2000) Adv. Drug Deliv. Rev.
41(2):147-62). In addition, it is also over-expressed in a number
of other cancers such as but not limited to breast, colorectal,
renal, and lung cancer.
[0004] In 1987, Miotti et al. described three new monoclonal
antibodies that recognized antigens on human ovarian carcinoma
cells (Miotti et al. (1987) Int. J. Cancer 39(3):297-303). One of
these was designated MOv18, which recognizes a 38 kDa protein on
the surface of choriocarcinoma cells. MOv18 is a murine, IgG1,
kappa antibody and mediates specific cell lysis of the ovarian
carcinoma cell line, IGROV1. Alberti et al. ((1990) Biochem.
Biophys. Res. Commun. 171(3):1051-1055) showed that the antigen
recognized by MOv18 was a GPI-linked protein. This was subsequently
identified as the human folate binding protein (Coney et al. (1991)
Cancer Res. 51(22):6125-6132). Tomassetti et al. showed that MOv18
recognizes a soluble form and a GPI-anchored form of the folate
binding protein in IGROV1 cells (Tomassetti et al. (1993) FEBS
Lett. 317(1-2):143-146). Subsequent work combined the variable
regions of the mouse MOv18 with human IgGI (kappa) constant region
to create a chimerized MOv18 antibody. The chimerized antibody
mediated higher and more specific lysis of IGROV1 cells at 10-100
fold lower antibody concentrations (Coney et al. (1994) Cancer Res.
54(9):2448-2455).
[0005] U.S. Pat. No.5,952,484 describes a humanized antibody that
binds to a 38 kDa protein (FR-.alpha.). The antibody was named
LK26, after the antigen by the same name. The original mouse
monoclonal antibody was described by Rettig in European Patent
Application No. 86104170.5 (published as EP0197435 and issued in
the U.S. as U.S. Pat. No. 4,851,332).
[0006] Ovarian cancer is the major cause of death due to
gynecological malignancy. Although chemotherapy is the recommended
treatment and has enjoyed some success, the 5-year survival term is
still less than 40%.
[0007] A difficult problem in treating ovarian cancer as well as
other cancers with cytotoxic drugs is that often the cytotoxin
causes toxicity to normal tissues as well as cancerous tissues. An
approach to get better specificity to treat cancer is the use of
antibodies that can target specific antigens expressed in cancer
cells that are not expressed or are expressed at a lower level on
normal cells. These targets can be exploited using antibodies to
kill antigen-bearing tumors by inhibiting the biological activity
of the antigen, eliciting an immune effector function by complement
dependent cytotoxicity (CDC) and/or antibody dependent cellular
cytotoxicity (ADCC); or by delivering immuno- or radio-conjugates
that when delivered to the antigen-bearing cells, specifically kill
the target cell. Finding antibodies that can specifically bind to
and effectively kill antigen-bearing tumor cells has proven
difficult for many cancers. This has been due in part to the
inability to obtain robust killing due to lack of immune-effector
function or to lack of efficient internalization of antibodies
carrying immunotoxins. FRA offers an opportunity to get
tumor-specific targeting for several cancer types including
ovarian, renal, colorectal and lung cancer.
[0008] Provided herein are in-out anti-FRA antibodies that can in
the alternative (i.e., have the ability to do both but only one at
a time) elicit a robust immune-effector function on and internalize
in FRA-positive cells, for example, for delivering toxic conjugates
to FRA-positive cells. The antibodies of the invention are
effective therapies for cancers that bear FRA such as but not
limited to ovarian, renal, colorectal, breast and lung cancers.
SUMMARY OF THE INVENTION
[0009] Provided herein are FRA-specific antibodies that
alternatively elicit a robust immune-effector function yet are able
to internalize in FRA-positive cells, referred to here as in-out
anti-FRA antibodies. As used herein, "in-out antibodies" ("in-out
Abs") refer to antibodies that can alternatively elicit an immune
effector activity and internalize within an antigen-presenting cell
by binding to target antigen. Without wishing to be bound by any
particular theory, it is believed that in-out Abs bind to the cell
surface of an antigen-bearing cell and internalize after a period
of time unless engaged by immune-effector cells or biochemicals
that are recruited to the antigen-antibody-bearing cell. Antibodies
that are able to elicit an immune effector effect such ADCC or CDC
and internalize have been previously described (Wolff et al.
Monoclonal antibody homodimers: enhanced antitumor activity in nude
mice. Cancer Res. Jun. 1, 1993;53:2560-5), however, it is not
obvious that in-out antibodies can be developed against any antigen
or epitope (Kusano et al. Immunocytochemical study on
internalization of anti-carbohydrate monoclonal antibodies.
Anticancer Res. November-December 1993;13(6A):2207-12). In-out
antibodies that can target FRA have not been described previously.
FRA-specific antibodies have been previously described but such
antibodies are not known to internalize upon binding to the antigen
(Cogliati et al. Preparation and biological characterization of
conjugates consisting of ricin and a tumor-specific
non-internalizing MAb. Anticancer Res. 11:417-21, 1991). Antibodies
that can target cell surface antigens do not always elicit an
immune effector function upon binding to the cell surface antigen
(Niwa et al. Defucosylated chimeric anti-CC chemokine receptor 4
IgG1 with enhanced antibody-dependent cellular cytotoxicity shows
potent therapeutic activity to T-cell leukemia and lymphoma. Cancer
Res. 64:2127-33, 2004; Kikuchi et al. Apoptosis inducing bivalent
single-chain antibody fragments against CD47 showed antitumor
potency for multiple myeloma. Leuk Res. 29:445-50, 2005; Scott et
al. Immunological effects of chimeric anti-GD3 monoclonal antibody
KM871 in patients with metastatic melanoma. Cancer Immun. February
22;5:3, 2005). Provided herein are antibodies that bind to the cell
surface antigen FRA and, in the alternative, elicit an immune
effector activity (such as ADCC or CDC) and internalize within
antigen-positive cells. These antibodies and derivatives thereof
are useful for cancer therapy.
[0010] The invention provides in-out antibodies that specifically
bind to FRA. In some embodiments, the antibodies bind antigen with
greater affinity and/or avidity than LK26 and MOv18. In some
embodiments the in-out antibodies of the invention bind the same
epitope, for example a conformational epitope, as that bound by
LK26 or MOv18. In other embodiments, the in-out antibodies of the
invention bind a different epitope as that bound by LK26 or
MOv18.
[0011] The antibodies of the invention may be chimeric, including,
but not limited to a human-mouse chimeric antibodies. The
antibodies of the invention may also be humanized. The antibodies
of the invention may also be fully human. The invention also
provides: hybridoma cells that express the antibodies of the
invention; polynucleotides that encode the antibodies of the
invention; vectors comprising the polynucleotides that encode the
antibodies of the invention; and expression cells comprising the
polynucleotides of the invention, referred to as transfectomas.
[0012] The invention also provides methods of producing in-out
antibodies of the invention. Some methods comprise the step of
culturing the transfectoma or hybridoma cell that expresses an
antibody of the invention. The antibody-producing cells of the
invention may be bacterial, yeast, insect cells, and animal cells,
preferably, mammalian cells.
[0013] The invention further provides methods of inhibiting the
growth of FRA-positive cells such as dysplastic or tumor cells
associated with increased expression of FRA. In some embodiments,
such methods comprise administering to a patient with FRA-positive
cells a composition comprising an in-out antibody of the invention.
The methods may be used for the treatment of various dysplastic
conditions, such as, but not limited to ovarian, breast,
colorectal, renal and lung cancer. In preferred embodiments, the
patients are human patients. In some embodiments, the antibodies
are conjugated to one or more chemotherapeutic agents such as, but
not limited to radionuclides, toxins, and cytotoxic or cytostatic
agents. In other embodiments the antibodies are used in combination
with one or more chemotherapeutic agents or biomolecules. Yet in
other embodiments the antibodies are used in combination with an
antifolate compound. In-out antibodies can be administered as a
single agent, as a conjugated or unconjugated antibody, or in
combination with the conjugated or unconjugated forms or another
therapeutic agent.
[0014] Previous attempts to develop therapeutic antibodies that
specifically target FRA have been performed with little success due
to poor internalization and/or affinity such as the MOv 18 antibody
(Cogliati et al. Preparation and biological characterization of
conjugates consisting of ricin and a tumor-specific
non-internalizing MAb. Anticancer Res. 11:417-21, 1991). This lack
of internalization could be due to low affinity or poor
internalization due to antibody composition and/or epitope binding.
In addition, the MOv18 antibody was attempted as an immunoconjugate
because the unconjugated form was not cytotoxic itself. Provided
herein are in-out antibodies that alternatively internalize in
FRA-positive cells and elicit a cytotoxic effect via an immune
effector activity.
[0015] Other features and advantages of the invention will be
apparent from the detailed description and examples that
follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 shows a FRA-specific binding antibody ML-1 by ELISA
and FACS. FIG. 1A demonstrates FRA-specific antibodies that have
in-out activity (ML-1). Shown is an ELISA identifying antibody that
can specifically bind to various amounts of recombinant FRA
antigen. ELISAs also can be formatted using purified,
semi-purified, membrane preps or whole cells expressing FRA. FIG.
1B shows the results of FACS analysis of ML-1 binding to
FRA-expressing cells (IGROV-1) while no binding is observed on
FRA-null H226 cells. These data were confirmed by western blot
analysis.
[0017] FIG. 2 demonstrates that ML-1 elicits a robust
antibody-dependent cellular cytotoxicity (ADCC) activity. Tumor
cell line OVCAR3 (referred to as target) which expresses FRA was
incubated with human peripheral blood mononuclear cells (PBMCs)
alone (no Ab lane); with ML-1; or control Ig (normal IgG). Cell
cultures were assayed for killing by monitoring for lactate
dehydrogenase (LDH) release that occurs upon cell lysis. ML-1 has
ADCC activity on FRA-expressing cells.
[0018] FIG. 3 demonstrates that ML-1 internalizes in FRA-expressing
cells. FIG. 3 shows the ability of ML-1 linked to saporin (diamond)
to kill cells in contrast to ML-1 unconjugated (square) while an
isotype control antibody MORAb-A92 did not kill cells in conjugated
or unconjugated toxin form (triangle and X, respectively). As
control, cells not expressing FRA were used and found that ML-1 has
no toxic effect in toxin-conjugated or unconjugated form (not
shown). These data support the finding that ML-1 internalizes in
FRA-bearing cells. Data is evaluated by comparing treated and
untreated wells and results are expressed as percent of
control.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0019] The reference works, patents, patent applications, and
scientific literature, including accession numbers to GenBank
database sequences that are referred to herein establish the
knowledge of those with skill in the art and are hereby
incorporated by reference in their entirety to the same extent as
if each was specifically and individually indicated to be
incorporated by reference. Any conflict between any reference cited
herein and the specific teachings of this specification shall be
resolved in favor of the latter. Likewise, any conflict between an
art-understood definition of a word or phrase and a definition of
the word or phrase as specifically taught in this specification
shall be resolved in favor of the latter.
[0020] Standard reference works setting forth the general
principles of recombinant DNA technology known to those of skill in
the art include Ausubel et al. CURRENT PROTOCOLS IN MOLECULAR
BIOLOGY, John Wiley & Sons, New York (1998); Sambrook et al.
MOLECULAR CLONING: A LABORATORY MANUAL, 2D ED., Cold Spring Harbor
Laboratory Press, Plainview, N.Y. (1989); Kaufman et al., Eds.,
HANDBOOK OF MOLECULAR AND CELLULAR METHODS IN BIOLOGY AND MEDICINE,
CRC Press, Boca Raton (1995); McPherson, Ed., DIRECTED MUTAGENESIS:
A PRACTICAL APPROACH, IRL Press, Oxford (1991).
[0021] It is to be understood that this invention is not limited to
particular methods, reagents, compounds, compositions or biological
systems, which can, of course, vary. It is also to be understood
that the terminology used herein is for the purpose of describing
particular embodiments only, and is not intended to be limiting. As
used in this specification and the appended claims, the singular
forms "a", "an" and "the" include plural referents unless the
content clearly dictates otherwise. Thus, for example, reference to
"a cell" includes a combination of two or more cells, and the
like.
[0022] Each range recited herein includes all combinations and
sub-combinations of ranges, as well as specific numerals contained
therein.
[0023] The term "about" as used herein when referring to a
measurable value such as an amount, a temporal duration, and the
like, is meant to encompass variations of .+-.20% or .+-.10%, more
preferably .+-.5%, even more preferably .+-.1%, and still more
preferably .+-.0.1% from the specified value, as such variations
are appropriate to perform the disclosed methods.
[0024] The invention provides a method for inhibiting the growth of
FRA-positive cells, such as but not limited to cancer cells. Such a
method may be used to inhibit the progression of neoplastic disease
using in-out antibodies that specifically bind to FRA, preferably
mammalian FRA, more preferably human FRA (SEQ ID NOs:1 (nucleotide)
and 2 (amino acid)). The methods of the invention may be used to
modulate the growth of FRA-positive cells, for example, to treat
cancer in mammals, including humans. The cancer cells that may be
inhibited include all cancer cells that have an increased
expression of FRA in relation to normal human tissues, particularly
ovarian, breast, colorectal and lung cancer cells.
[0025] Without wishing to be bound by any particular theory of
operation, it is believed that the increased expression of FRA in
cancer cells results in an increased cell surface expression of the
membrane bound form on the surface of the cells. Therefore, some
cancer cells have an increased expression of FRA relative to normal
tissues. Thus, the membrane bound FRA is an ideal target for
antibody therapy in cancer.
[0026] As used herein, the term "epitope" refers to the portion of
an antigen to which an antibody specifically binds.
[0027] As used herein, the term "conformational epitope" refers to
a discontinuous epitope formed by a spatial relationship between
amino acids of an antigen other than an unbroken series of amino
acids.
[0028] As used herein, the terms "immune effector activity,"
"immune effector effect," and "immune effector function" refer to
the ability of an antibody to kill cells by antibody-dependent
cellular cytotoxicity (ADCC) or complement-dependent cytotoxicity
(CDC).
[0029] As used herein, the term "in-out antibody" refers to an
antibody that can internalize within an antigen-presenting cell
and, if not internalized, elicits an immune-effector activity.
[0030] As used herein, the phrase "in the alternative" when
referring to the ability of an antibody to internalize or elicit an
immune effector activity means that the antibody has the ability to
both internalize and elicit an immune effector activity but cannot
do both simultaneously.
[0031] As used herein, the term "inhibition of growth of dysplastic
cells in vitro" means a decrease in the number of cells, in
culture, by about 5%, preferably about 10%, more preferably about
20%, more preferably about 30%, more preferably about 40%, more
preferably about 50%, more preferably about 60%, more preferably
about 70%, more preferably about 80%, more preferably about 90%,
and most preferably about 100%. In vitro inhibition of tumor cell
growth may be measured by assays known in the art.
[0032] As used herein, the term "inhibition of growth of dysplastic
cells in vivo" means a decrease in the number of cells in an
organism by about 5%, preferably about 10%, more preferably about
20%, more preferably about 30%, more preferably about 40%, more
preferably about 50%, more preferably about 60%, more preferably
about 70%, more preferably about 80%, more preferably about 90%,
and most preferably about 100%. In vivo modulation of cell growth
may be measured by assays known in the art.
[0033] As used herein, "dysplastic cells" refer to cells that
exhibit abnormal growth. Examples of abnormal growth properties
include but are not limited to growth in soft agar, lack of contact
inhibition, failure to undergo cell cycle arrest in the absence of
serum, and formation of tumors when injected into
immuno-compromised mice Dysplastic cells include, but are not
limited to tumors, hyperplasia, and the like.
[0034] The term "preventing" refers to decreasing the probability
that an organism contracts or develops an abnormal condition such
as dysplasia.
[0035] The term "treating" refers to having a therapeutic effect
and at least partially alleviating or abrogating an abnormal
condition in the organism. Treating includes maintenance of
inhibited tumor growth and induction of remission.
[0036] "Therapeutic effect" refers to the reduction, elimination,
or prevention of a disease or abnormal condition, symptoms thereof,
or side effects thereof in the subject. "Effective amount" refers
to an amount necessary to produce a desired effect. A
"therapeutically effective amount" means the amount that, when
administered to a subject for treating a disease, condition or
disorder, is sufficient to effect treatment for that disease. A
therapeutic effect relieves to some extent one or more of the
symptoms of the abnormal condition. In reference to the treatment
of abnormal conditions, a therapeutic effect can refer to one or
more of the following: (a) an increase or decrease in the
proliferation, growth, and/or differentiation of cells; (b)
inhibition (i.e., slowing or stopping) of growth of tumor cells in
vivo (c) promotion of cell death; (d) inhibition of degeneration;
(e) relieving to some extent one or more of the symptoms associated
with the abnormal condition; and (f) enhancing the function of a
population of cells. The antibodies and derivatives thereof
described herein effectuate the therapeutic effect alone or in
combination with conjugates or additional components of the
compositions of the invention.
[0037] As used herein, the term "inhibits the progression of cancer
or neoplastic disease" refers to an activity of a treatment that
slows the modulation of neoplastic disease toward end-stage cancer
in relation to the modulation toward end-stage disease of untreated
cancer cells.
[0038] As used herein, the term "neoplastic disease" refers to a
condition marked by abnormal proliferation of cells of a
tissue.
[0039] As used herein the term "biomolecule" refers to any molecule
that can be conjugated to, coadministered with, administered before
or after administering the antibody, or otherwise used in
association with the antibody of the invention. Biomolecules
include, but are not limited to, enzymes, proteins, peptides, amino
acids, nucleic acids, lipids, carbohydrates, and fragments,
homologs, analogs, or derivatives, and combinations thereof.
Examples of biomolecules include but are not limited to
interleukin-2, interferon alpha, interferon beta, interferon gamma,
rituxan, zevalin, herceptin, erbitux, and avastin. The biomolecules
can be native, recombinant, or synthesized, and may be modified
from their native form with, for example, glycosylations,
acetylations, phosphorylations, myristylations, and the like. The
term biomolecule as it is used herein is not limited to naturally
occurring molecules, and includes synthetic molecules having no
biological origin.
[0040] As used herein, the term "cytotoxic" or "cytostatic" agent
refers to an agent that reduces the viability or proliferative
potential of a cell. Cytotoxic or cytostatic agents can function in
a variety of ways to reduce cell viability or proliferation, for
example, but not by way of limitation, by inducing DNA damage,
inducing cell cycle arrest, inhibiting DNA synthesis, inhibiting
transcription, inhibiting translation or protein synthesis,
inhibiting cell division, or inducing apoptosis. As used herein,
the term "chemotherapeutic agent" refers to cytotoxic, cytostatic,
and antineoplastic agents that preferentially kill, inhibit the
growth of, or inhibit the metastasis of neoplastic cells or disrupt
the cell cycle of rapidly proliferating cells. Specific examples of
chemotherapeutic agents include, but are not limited to,
radionuclides, pokeweed antiviral protein, abrin, ricin and each of
their A chains, altretamine, actinomycin D, plicamycin, puromycin,
gramicidin D, doxorubicin, colchicine, cytochalasin B,
cyclophosphamide, emetine, maytansine, amsacrine, cisplastin,
etoposide, etoposide orthoquinone, teniposide, daunorubicin,
gemcitabine, doxorubicin, mitoxantraone, bisanthrene, Bleomycin,
methotrexate, vindesine, adriamycin, vincristine, vinblastine,
BCNU, taxol, tarceva, avastin, mitomycin, modified Pseudomonas
enterotoxin A, calicheamicin, 5-fluorouracil, cyclophosphamide and
certain cytokines such as TNF-alpha and TNF-beta.
[0041] "Conservatively modified variants" applies to both amino
acid and nucleic acid sequences. With respect to particular nucleic
acid sequences, conservatively modified variants refers to those
nucleic acids which encode identical or essentially identical amino
acid sequences, or where the nucleic acid does not encode an amino
acid sequence, to essentially identical sequences. Because of the
degeneracy of the genetic code, a large number of functionally
identical nucleic acids encode any given protein. For instance, the
codons GCA, GCC, GCG and GCU all encode the amino acid alanine.
Thus, at every position where an alanine is specified by a codon,
the codon can be altered to any of the corresponding codons
described without altering the encoded polypeptide. Such nucleic
acid variations are "silent variations," which are one species of
conservatively modified variations. Every nucleic acid sequence
herein which encodes a polypeptide also describes every possible
silent variation of the nucleic acid. One of skill will recognize
that each codon in a nucleic acid (except AUG, which is ordinarily
the only codon for methionine, and TGG, which is ordinarily the
only codon for tryptophan) can be modified to yield a functionally
identical molecule. Accordingly, each silent variation of a nucleic
acid which encodes a polypeptide is implicit in each described
sequence with respect to the expression product, but not with
respect to actual probe sequences.
[0042] "Recombinant" when used with reference, e.g., to a cell, or
nucleic acid, protein, or vector, indicates that the cell, nucleic
acid, protein or vector, has been modified by the introduction of a
heterologous nucleic acid or protein or the alteration of a native
nucleic acid or protein, or that the cell is derived from a cell so
modified. Thus, for example, recombinant cells express genes that
are not found within the native (non-recombinant) form of the cell
or express native genes that are otherwise abnormally expressed,
under expressed or not expressed at all.
[0043] The phrase "nucleic acid" or "polynucleotide sequence"
refers to a single or double-stranded polymer of
deoxyribonucleotide or ribonucleotide bases read from the 5' to the
3' end. Nucleic acids can also include modified nucleotides that
permit correct read through by a polymerase and do not alter
expression of a polypeptide encoded by that nucleic acid,
including, for example, conservatively modified variants.
[0044] "Polypeptide," "peptide" and "protein" are used
interchangeably herein to refer to a polymer of amino acid
residues. The terms apply to amino acid polymers in which one or
more amino acid residue is an artificial chemical mimetic of a
corresponding naturally occurring amino acid, as well as to
naturally occurring amino acid polymers and non-naturally occurring
amino acid polymers. Polypeptides of the invention, including
antibodies of the invention, include conservatively modified
variants. One of skill will recognize that substitutions, deletions
or additions to a nucleic acid, peptide, polypeptide, or protein
sequence which alter, add or delete a single amino acid or a small
percentage of amino acids in the encoded sequence is a
"conservatively modified variant" where the alteration results in
the substitution of an amino acid with a chemically similar amino
acid. Conservative substitution tables providing functionally
similar amino acids are well known in the art. Such conservatively
modified variants are in addition to and do not exclude polymorphic
variants, interspecies homologs, and alleles of the invention. The
following eight groups each contain amino acids that are
conservative substitutions for one another: 1) Alanine (A), Glycine
(G); 2) Aspartic acid (D), Glutamic acid (E); 3) Asparagine (N),
Glutamine (Q); 4) Arginine (R), Lysine (K); 5) Isoleucine (I),
Leucine (L), Methionine (M), Valine (V); 6) Phenylalanine (F),
Tyrosine (Y), Tryptophan (W); 7) Serine (S), Threonine (T); and 8)
Cysteine (C), Methionine (M) (33). The term "conservative
substitution" also includes the use of a substituted amino acid in
place of an unsubstituted parent amino acid provided that such a
polypeptide also displays the requisite binding activity.
[0045] "Amino acid" refers to naturally occurring and synthetic
amino acids, as well as amino acid analogs and amino acid mimetics
that function in a manner similar to the naturally occurring amino
acids. Naturally occurring amino acids are those encoded by the
genetic code, as well as those amino acids that are later modified,
e.g., hydroxyproline, y-carboxyglutamate, and O-phosphoserine.
"Amino acid analog" refers to compounds that have the same basic
chemical structure as a naturally occurring amino acid, i.e., an a
carbon that is bound to a hydrogen, a carboxyl group, an amino
group, and an R group, e.g., homoserine, norleucine, methionine
sulfoxide, methionine methyl sulfonium. Such analogs have modified
R groups (e.g., norleucine) or modified peptide backbones but
retain the same basic chemical structure as a naturally occurring
amino acid. "Amino acid mimetic" refers to a chemical compound
having a structure that is different from the general chemical
structure of an amino acid but that functions in a manner similar
to a naturally occurring amino acid.
[0046] Amino acids can be referred to herein by either their
commonly known three letter symbols or by the one-letter symbols
recommended by the IUPAC-IUB Biochemical Nomenclature Commission
(see Table 1 below). Nucleotides, likewise, can be referred to by
their commonly accepted single-letter codes. TABLE-US-00001 TABLE 1
SYMBOL 1 -Letter 3 -Letter AMINO ACID Y Tyr L-tyrosine G Gly
L-glycine F Phe L-phenylalanine M Met L-methionine A Ala L-alanine
S Ser L-serine I Ile L-isoleucine L Leu L-leucine T Thr L-threonine
V Val L-valine P Pro L-proline K Lys L-lysine H His L-histidine Q
Gln L-glutamine E Glu L-glutamic acid W Trp L-tryptophan R Arg
L-arginine D Asp L-aspartic acid N Asn L-asparagine C Cys
L-cysteine
[0047] It should be noted that all amino acid sequences are
represented herein by formulae whose left to right orientation is
in the conventional direction of amino-terminus to
carboxy-terminus.
[0048] As used herein, the term "in vitro" or "ex vivo" refers to
an artificial environment and to processes or reactions that occur
within an artificial environment, for example, but not limited to,
test tubes and cell cultures. The term "in vivo" refers to a
natural environment (e.g., an animal or a cell) and to processes or
reactions that occur within a natural environment.
[0049] "Pharmaceutically acceptable," "physiologically tolerable"
and grammatical variations thereof, as they refer to compositions,
carriers, diluents and reagents, are used interchangeably and
represent that the materials are capable of administration to or
upon a human without the production of undesirable physiological
effects to a degree that would prohibit administration of the
composition.
[0050] The term "pharmaceutically acceptable carrier" refers to
reagents, excipients, cells, compounds, materials, compositions,
and/or dosage forms which are, within the scope of sound medical
judgment, suitable for use in contact with the tissues of human
beings and animals without excessive toxicity, irritation, allergic
response, or other complication commensurate with a reasonable
benefit/risk ratio. As described in greater detail herein,
pharmaceutically acceptable carriers suitable for use in the
present invention include gases, liquids, and semi-solid and solid
materials.
[0051] Except when noted, "subject" or "patient" are used
interchangeably and refer to mammals such as human patients and
non-human primates, as well as experimental animals such as
rabbits, dogs, cats, rats, mice, and other animals. Accordingly,
"subject" or "patient" as used herein means any mammalian patient
or subject to which the compositions of the invention can be
administered. In some embodiments of the present invention, the
patient will be suffering from an infectious or inflammatory
disease. In some embodiments of the present invention, the patient
will have been diagnosed with cancer. In an exemplary embodiment of
the present invention, to identify candidate patients for treatment
according to the invention, accepted screening methods are employed
to determine the status of an existing disease or condition in a
subject or risk factors associated with a targeted or suspected
disease or condition. These screening methods include, for example,
examinations to determine whether a subject is suffering from an
infectious disease, an inflammatory disease, or cancer. These and
other routine methods allow the clinician to select subjects in
need of therapy.
[0052] "Therapeutic compound" as used herein refers to a compound
useful in the prophylaxis or treatment of a disease or condition
such as cancer.
[0053] "Concomitant administration," "concurrent administration,"
or "co-administration" as used herein includes administration of
the active agents (e.g., MAbs, chemotherapeutic agents,
biomolecules), in conjunction or combination, together, or before
or after each other. The multiple agent(s) may be administered by
the same or by different routes, simultaneously or sequentially, as
long as they are given in a manner sufficient to allow all agents
to achieve effective concentrations at the site of action. A person
of ordinary skill in the art would have no difficulty determining
the appropriate timing, sequence, and dosages of administration for
particular drugs and compositions of the present invention.
[0054] "Immunoglobulin" or "antibody" is used broadly to refer to
both antibody molecules and a variety of antibody-derived molecules
and includes any member of a group of glycoproteins occurring in
higher mammals that are major components of the immune system. The
term "antibody" is used in the broadest sense and specifically
covers monoclonal antibodies, antibody compositions with
polyepitopic specificity, bispecific antibodies, diabodies, and
single-chain molecules, as well as antibody fragments (e.g., Fab,
F(ab').sub.2, and Fv), so long as they exhibit the desired
biological activity. An immunoglobulin molecule includes antigen
binding domains, which each include the light chains and the
end-terminal portion of the heavy chain, and the Fc region, which
is necessary for a variety of functions, such as complement
fixation. There are five classes of immunoglobulins wherein the
primary structure of the heavy chain, in the Fc region, determines
the immunoglobulin class. Specifically, the alpha, delta, epsilon,
gamma, and mu chains correspond to IgA, IgD, IgE, IgG and IgM,
respectively. As used herein "immunoglobulin" or "antibody"
includes all subclasses of alpha, delta, epsilon, gamma, and mu and
also refers to any natural (e.g., IgA and IgM) or synthetic
multimers of the four-chain immunoglobulin structure. Antibodies
non-covalently, specifically, and reversibly bind an antigen. The
term "monoclonal antibody" as used herein refers to an antibody
obtained from a population of substantially homogeneous antibodies,
i.e., the individual antibodies comprising the population are
identical except for possible naturally occurring mutations that
can be present in minor amounts. For example, monoclonal antibodies
may be produced by a single clone of antibody-producing cells.
Unlike polyclonal antibodies, monoclonal antibodies are
monospecific (e.g., specific for a single epitope of a single
antigen). The modifier "monoclonal" indicates the character of the
antibody as being obtained from a substantially homogeneous
population of antibodies, and is not to be construed as requiring
production of the antibody by any particular method. For example,
the monoclonal antibodies to be used in accordance with the present
invention can be made by the hybridoma method first described by
Kohler et al., Nature, 256: 495, 1975, or can be made by
recombinant DNA methods. The "monoclonal antibodies" can also be
isolated from phage antibody libraries using the techniques
described in Marks et al., J. Mol. Biol., 222: 581-597, 1991, for
example.
[0055] Antibody-derived molecules comprise portions of intact
antibodies that retain antigen-binding specificity, and comprise,
for example, at least one variable region (either a heavy chain or
light chain variable region). Antibody-derived molecules, for
example, include molecules such as Fab fragments, Fab' fragments,
F(ab').sub.2 fragments, Fd fragments, F(v) fragments, Fabc
fragments, Fd fragments, Fabc fragments, Sc antibodies (single
chain antibodies), diabodies, individual antibody light chains,
individual antibody heavy chains, chimeric fusions between antibody
chains and other molecules, heavy chain monomers or dimers, light
chain monomers or dimers, dimers consisting of one heavy and one
light chain, and the like. All classes of immunoglobulins (e.g.,
IgA, IgD, IgE, IgG and IgM) and subclasses thereof are
included.
[0056] Antibodies can be labeled or conjugated to toxic or
non-toxic moieties. Toxic moieties include, for example, bacterial
toxins, viral toxins, radioisotopes, and the like. Antibodies can
be labeled for use in biological assays (e.g., radioisotope labels,
fluorescent labels) to aid in detection of the antibody. Antibodies
can also be labeled/conjugated for diagnostic or therapeutic
purposes, e.g., with radioactive isotopes that deliver radiation
directly to a desired site for applications such as
radioimmunotherapy (Garmestani et al., Nucl. Med. Biol., 28: 409,
2001), imaging techniques and radioimmunoguided surgery or labels
that allow for in vivo imaging or detection of specific
antibody/antigen complexes. Antibodies may also be conjugated with
toxins to provide an immunotoxin (see, Kreitman, R. J. Adv. Drug
Del. Rev., 31: 53, 1998).
[0057] With respect to antibodies, the term, "immunologically
specific" refers to antibodies that bind to one or more epitopes of
a protein of interest, but which do not substantially recognize and
bind other molecules in a sample containing a mixed population of
antigenic biological molecules.
[0058] "Chimeric" or "chimerized" antibodies (immunoglobulins)
refer to antibodies in which a portion of the heavy and/or light
chain is identical with or homologous to corresponding sequences in
antibodies derived from a particular species or belonging to a
particular antibody class or subclass, while the remainder of the
chain(s) is identical with or homologous to corresponding sequences
in antibodies derived from another species or belonging to another
antibody class or subclass, as well as fragments of such
antibodies, so long as they exhibit the desired biological activity
(Morrison et al., Proc. Natl. Acad. Sci. U.S.A., 81: 6851-6855,
1984).
[0059] "Humanized" forms of non-human (e.g., murine) antibodies are
chimeric immunoglobulins, immunoglobulin chains or fragments
thereof (such as Fv, Fab, Fab', F(ab').sub.2 or other
antigen-binding subsequences of antibodies) which contain minimal
sequence derived from non-human immunoglobulin. For the most part,
humanized antibodies are human immunoglobulins (recipient antibody)
in which residues from a complementary-determining region (CDR) of
the recipient are replaced by residues from a CDR of a non-human
species (donor antibody) such as mouse, rat or rabbit having the
desired specificity, affinity, and capacity. In some instances, Fv
framework region (FR) residues of the human immunoglobulin are
replaced by corresponding non-human residues. Furthermore,
humanized antibodies can comprise residues which are found neither
in the recipient antibody nor in the imported CDR or framework
sequences. These modifications are made to further refine and
optimize antibody performance. In general, the humanized antibody
will comprise substantially all of at least one, and typically two,
variable domains, in which all or substantially all of the CDR
regions correspond to those of a non-human immunoglobulin and all
or substantially all of the FR regions are those of a human
immunoglobulin sequence. The humanized antibody optimally also will
comprise at least a portion of an immunoglobulin constant region
(Fc), typically that of a human immunoglobulin. For further
details, see Jones et al., Nature, 321: 522-525, 1986; Reichmann et
al., Nature, 332: 323-329, 1988; Presta, Curr. Op. Struct. Biol.,
2: 593-596, 1992.
[0060] "Fully human" refers to an immunoglobulin, such as an
antibody, where the whole molecule is of human origin or consists
of an amino acid sequence identical to a human form of the
antibody.
[0061] "Hybridoma" refers to the product of a cell-fusion between a
cultured neoplastic lymphocyte and a primed B- or T-lymphocyte
which expresses the specific immune potential of the parent
cell.
[0062] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which the invention pertains. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice for testing of the present
invention, the preferred materials and methods are described
herein. In describing and claiming the present invention, the
following terminology will be used.
[0063] Various patents and other publications are cited herein and
throughout the specification, each of which is incorporated by
reference herein in its entirety.
[0064] Antibodies
[0065] The antibodies of the invention specifically bind FRA and
exhibit in-out activity (i.e., in the alternative, the ability to
induce an immune effector activity and the ability to internalize
in endosialin-positive cells). In some embodiments, the antibodies
bind to the same epitope as LK26 or MOv18. In other embodiments,
the antibodies bind to an epitope other than that bound by LK26 or
MOv18. FRA to which the antibodies of the invention bind is
preferably mammalian, more preferably human. Human FRA is encoded
by SEQ ID NO:1 and comprises an amino acid sequence of SEQ ID
NO:2:
[0066] SEQ ID NO 1: cDNA of human mature folate receptor alpha
TABLE-US-00002 1 attgcatggg ccaggactga gcttctcaat gtctgcatga
acgccaagca ccacaaggaa 61 aagccaggcc ccgaggacaa gttgcatgag
cagtgtcgac cctggaggaa gaatgcctgc 121 tgttctacca acaccagcca
ggaagcccat aaggatgttt cctacctata tagattcaac 181 tggaaccact
gtggagagat ggcacctgcc tgcaaacggc atttcatcca ggacacctgc 241
ctctacgagt gctcccccaa cttggggccc tggatccagc aggtggatca gagctggcgc
301 aaagagcggg tactgaacgt gcccctgtgc aaagaggact gtgagcaatg
gtgggaagat 361 tgtcgcacct cctacacctg caagagcaac tggcacaagg
gctggaactg gacttcaggg 421 tttaacaagt gcgcagtggg agctgcctgc
caacctttcc atttctactt ccccacaccc 481 actgttctgt gcaatgaaat
ctggactcac tcctacaagg tcagcaacta cagccgaggg 541 agtggccgct
gcatccagat gtggttcgac ccagcccagg gcaaccccaa tgaggaggtg 601
gcgaggttct atgctgcago catgagtggg gctgggccct gggcagcctg gcctttcctg
661 cttagcctgg ccctaatgct gctgtggctg ctcagc
[0067] SEQ ID NO 2: polypeptide sequence of human mature folate
receptor alpha TABLE-US-00003 1 iawartelln vcmnakhhke kpgpedklhe
gcrpwrknac cstntsqeah kdvsylyrfn 61 wnhcgemapa ckrhfiqdtc
lyecspnlgp wiqqvdqswr kervlnvplc kedceqwwed 121 crtsytcksn
whkgwnwtsg fnkcavgaac qpfhfyfptp tvlcneiwth sykvsnysrg 181
sgrciqmwfd paqgnpneev arfyaaamsg agpwaawpfl lslalmllwl ls
[0068] Preferred antibodies, and antibodies suitable for use in the
methods of the invention, include, for example, fully human
antibodies, human antibody homologs, single chain antibodies,
humanized antibody homologs, chimeric antibodies, chimeric antibody
homologs, and monomers or dimers of antibody heavy or light chains
or mixtures thereof.
[0069] The antibodies of the invention may include intact
immunoglobulins of any isotype including types IgA, IgG, IgE, IgD,
IgM (as well as subtypes thereof). The light chains of the
immunoglobulin may be kappa or lambda.
[0070] The antibodies of the invention include portions of intact
antibodies that retain antigen-binding specificity, for example,
Fab fragments, Fab' fragments, F(ab').sub.2 fragments, F(v)
fragments, heavy chain monomers or dimers, light chain monomers or
dimers, dimers consisting of one heavy and one light chain, and the
like. Thus, antigen-binding fragments, as well as full-length
dimeric or trimeric polypeptides derived from the above-described
antibodies are themselves useful for exhibiting in-out
activity.
[0071] It was found that the direct use of rodent monoclonal
antibodies as human therapeutic agents led to human anti-rodent
antibody ("HARA") responses which occurred in a significant number
of patients treated with the rodent-derived antibody (Khazaeli, et
al. (1994) Immunother. 15:42-52). Chimeric antibodies containing
less rodent amino acid sequence were thought to circumvent the
problem of eliciting an immune response in humans.
[0072] Chimeric antibodies may be produced by recombinant DNA
technology in which all or part of the hinge and constant regions
of an immunoglobulin light chain, heavy chain, or both, have been
substituted for the corresponding regions from another animal's
immunoglobulin light chain or heavy chain. In this way, the
antigen-binding portion of the parent monoclonal antibody is
grafted onto the backbone of another species' antibody. One
approach, described in EP 0239400 to Winter et al. describes the
substitution of one species' complementarity determining regions
(CDRs) for those of another species, such as substituting the CDRs
from human heavy and light chain immunoglobulin variable region
domains with CDRs from mouse variable region domains. These altered
antibodies may subsequently be combined with human immunoglobulin
constant regions to form antibodies that are human except for the
substituted murine CDRs which are specific for the antigen. Methods
for grafting CDR regions of antibodies may be found, for example in
Riechmann et al. (1988) Nature 332:323-327 and Verhoeyen et al.
(1988) Science 239:1534-1536.
[0073] As a non-limiting example, a method of performing CDR
grafting may be performed by sequencing the mouse heavy and light
chains of the antibody of interest that binds to the target antigen
(e.g., FRA) and genetically engineering the CDR DNA sequences and
imposing these amino acid sequences to corresponding human V
regions by site-directed mutagenesis. Human constant region gene
segments of the desired isotype are added, and the chimeric heavy
and light chain genes are co-expressed in mammalian cells to
produce soluble antibody. A typical expression cell is a Chinese
Hamster Ovary (CHO) cell. Other expression cells include HEK293 and
myeloma cells. Suitable methods for creating the chimeric
antibodies may be found, for example, in Jones et al. (1986) Nature
321:522-525; Riechmann (1988) Nature 332:323-327; Queen et al.
(1989) Proc. Nat. Acad. Sci. USA 86:10029; and Orlandi et al.
(1989) Proc. Natl. Acad. Sci. USA 86:3833.
[0074] Further refinement of antibodies to avoid the problem of
HARA responses led to the development of "humanized antibodies."
Humanized antibodies are produced by recombinant DNA technology, in
which at least one of the amino acids of a human immunoglobulin
light or heavy chain that is not required for antigen binding has
been substituted for the corresponding amino acid from a nonhuman
mammalian immunoglobulin light or heavy chain. For example, if the
immunoglobulin is a mouse monoclonal antibody, at least one amino
acid that is not required for antigen binding is substituted using
the amino acid that is present on a corresponding human antibody in
that position. Without wishing to be bound by any particular theory
of operation, it is believed that the "humanization" of the
monoclonal antibody inhibits human immunological reactivity against
the foreign immunoglobulin molecule.
[0075] Queen et al. (1989) Proc. Nat. Acad. Sci. USA 86:10029-10033
and WO 90/07861 describe the preparation of a humanized antibody.
Human and mouse variable framework regions were chosen for optimal
protein sequence homology. The tertiary structure of the murine
variable region was computer-modeled and superimposed on the
homologous human framework to show optimal interaction of amino
acid residues with the mouse CDRs. This led to the development of
antibodies with improved binding affinity for antigen (which is
typically decreased upon making CDR-grafted chimeric antibodies).
Alternative approaches to making humanized antibodies are known in
the art and are described, for example, in Tempest (1991)
Biotechnology 9:266-271.
[0076] The antibodies of the invention include derivatives that are
modified, e.g., by the covalent attachment of any type of molecule
to the antibody such that covalent attachment does not prevent the
antibody from binding to its epitope. Examples of suitable
derivatives include, but are not limited to glycosylated antibodies
and fragments, acetylated antibodies and fragments, pegylated
antibodies and fragments, phosphorylated antibodies and fragments,
and amidated antibodies and fragments. The antibodies and
derivatives thereof of the invention may themselves be derivatized
by known protecting/blocking groups, proteolytic cleavage, linkage
to a cellular ligand or other proteins, and the like. Further, the
antibodies and derivatives thereof of the invention may contain one
or more non-classical amino acids.
[0077] The antibodies of the invention include variants having
single or multiple amino acid substitutions, deletions, additions,
or replacements that retain the biological properties (e.g.,
internalization, binding affinity or avidity, or immune effector
activity) of the antibodies of the invention. The skilled person
can produce variants having single or multiple amino acid
substitutions, deletions, additions or replacements. These variants
may include, inter alia: (a) variants in which one or more amino
acid residues are substituted with conservative or nonconservative
amino acids, (b) variants in which one or more amino acids are
added to or deleted from the polypeptide, (c) variants in which one
or more amino acids include a substituent group, and (d) variants
in which the polypeptide is fused with another peptide or
polypeptide such as a fusion partner, a protein tag or other
chemical moiety, that may confer useful properties to the
polypeptide, such as, for example, an epitope for an antibody, a
polyhistidine sequence, a biotin moiety and the like. Antibodies of
the invention may include variants in which amino acid residues
from one species are substituted for the corresponding residue in
another species, either at the conserved or nonconserved positions.
In another embodiment, amino acid residues at nonconserved
positions are substituted with conservative or nonconservative
residues. The techniques for obtaining these variants, including
genetic (suppressions, deletions, mutations, etc.), chemical, and
enzymatic techniques, are known to the person having ordinary skill
in the art. Antibodies of the invention also include antibody
fragments. A "fragment" refers to polypeptide sequences which are
preferably at least about 40, more preferably at least to about 50,
more preferably at least about 60, more preferably at least about
70, more preferably at least about 80, more preferably at least
about 90, and more preferably at least about 100 amino acids in
length, and which retain some biological activity or immunological
activity of the full-length sequence, for example, FRA binding
affinity or avidity, the ability to internalize, and immune
effector activity.
[0078] The invention also encompasses fully human antibodies such
as those derived from peripheral blood mononuclear cells of
FRA-linked cancer patients. Such cells may be fused with myeloma
cells, for example to form hybridoma cells producing fully human
antibodies against FRA.
[0079] The antibodies and derivatives thereof of the invention have
binding affinities that include a dissociation constant (K.sub.d)
of less than 1.times.10.sup.-2. In some embodiments, the K.sub.d is
less than 1.times.10.sup.-3. In other embodiments, the K.sub.d is
less than 1.times.10.sup.-4. In some embodiments, the K.sub.d is
less than 1.times.10.sup.-5. In still other embodiments, the
K.sub.d is less than 1.times.10.sup.-6. In other embodiments, the
K.sub.d is less than 1.times.10.sup.-7. In other embodiments, the
K.sub.d is less than 1.times.10.sup.-8. In other embodiments, the
K.sub.d is less than 1.times.10.sup.-9. In other embodiments, the
K.sub.d is less than 1.times.10.sup.-10. In still other
embodiments, the K.sub.d is less than 1.times.10.sup.-11. In some
embodiments, the K.sub.d is less than 1.times.10.sup.-12. In other
embodiments, the K.sub.d is less than 1.times.10.sup.-13. In other
embodiments, the K.sub.d is less than 1.times.10.sup.-14. In still
other embodiments, the K.sub.d is less than 1.times.10.sup.-15.
[0080] Without wishing to be bound by any particular theory of
operation, it is believed that the antibodies of the invention are
particularly useful to bind FRA due to an increased avidity of the
antibody as both "arms" of the antibody (F.sub.ab fragments) bind
to separate FRA molecules. This leads to a decrease in the
dissociation (K.sub.d) of the antibody and an overall increase in
the observed affinity (K.sub.D). In addition, antibodies of this
invention must bind to epitopes that allow for the internalization
of the antibody-antigen complex. These are especially good features
for targeting tumors as the antibodies of the invention will bind
more tightly to tumor tissue than normal tissue to attract immune
cells for cytotoxicity and be capable of internalizing for delivery
of conjugated agents for added therapeutic effects.
[0081] The antibodies of the invention may be used alone or with
one or more biomolecules or chemotherapeutic agents such as a
cytotoxic or cytostatic agent. In some embodiments, the
chemotherapeutic agent is a radioisotope, including, but not
limited to Lead-212, Bismuth-212, Astatine-2 11, Iodine-131,
Scandium-47, Rhenium-186, Rhenium-188, Yttrium-90, Iodine-123,
Iodine-125, Bromine-77, Indium-111, and fissionable nuclides such
as Boron-10 or an Actinide. In other embodiments, the
chemotherapeutic agent is a toxin or cytotoxic drug, including but
not limited to ricin, modified Pseudomonas enterotoxin A,
calicheamicin, adriamycin, 5-fluorouracil, and the like. Methods of
conjugation of antibodies and antibody fragments to such agents are
known in the literature.
[0082] Also included in the invention are cells producing the
in-out antibodies of the invention. The antibody-producing cells of
the invention may be bacterial, yeast, insect, and animal cells,
preferably, mammalian cells. For example, the antibody-producing
cells of the invention include insect cells, such as for example,
Spodoptera frugiperda cells; yeast cells, such as, for example,
Saccharomyces cerevisiae and Schizosaccharomyces pombe cells; and
mammalian cells such as, for example Chinese Hamster Ovary, baby
hamster kidney cells, human embryonic kidney line 293, normal dog
kidney cell lines, normal cat kidney cell lines, monkey kidney
cells, African green monkey kidney cells, COS cells, and
non-tumorigenic mouse myoblast G8 cells, fibroblast cell lines,
myeloma cell lines, mouse NIH/3T3 cells, LMTK cells, mouse sertoli
cells, human cervical carcinoma cells, buffalo rat liver cells,
human lung cells, human liver cells, mouse mammary tumor cells, TRI
cells, MRC 5 cells, and FS4 cells. Antibody-producing cells have
been placed with the Amer. Type Cult. Coll. (10801 University
Blvd., Manassas, Va. 20110-2209) on Apr. 24, 2006 and have been
assigned Access. No. ______. Examples of in-out antibodies of the
invention are antibodies produced by such cells.
[0083] Nucleic Acids
[0084] The invention also includes nucleic acids encoding the heavy
chain and/or light chain of the anti-FRA antibodies of the
invention. "Nucleic acid" or a "nucleic acid molecule" as used
herein refers to any DNA or RNA molecule, either single- or
double-stranded and, if single-stranded, the molecule of its
complementary sequence in either linear or circular form. In
discussing nucleic acid molecules, a sequence or structure of a
particular nucleic acid molecule may be described herein according
to the normal convention of providing the sequence in the 5' to 3'
direction. In some embodiments of the invention, nucleic acids are
"isolated." This term, when applied to a nucleic acid molecule,
refers to a nucleic acid molecule that is separated from sequences
with which it is immediately contiguous in the naturally occurring
genome of the organism in which it originated. For example, an
"isolated nucleic acid" may comprise a DNA molecule inserted into a
vector, such as a plasmid or virus vector, or integrated into the
genomic DNA of a prokaryotic or eukaryotic cell or host organism.
When applied to RNA, the term "isolated nucleic acid" refers
primarily to an RNA molecule encoded by an isolated DNA molecule as
defined above. Alternatively, the term may refer to an RNA molecule
that has been sufficiently separated from other nucleic acids with
which it would be associated in its natural state (i.e., in cells
or tissues). An isolated nucleic acid (either DNA or RNA) may
further represent a molecule produced directly by biological or
synthetic means and separated from other components present during
its production.
[0085] Nucleic acids of the invention include nucleic acids having
at least 80%, more preferably at least about 90%, more preferably
at least about 95%, and most preferably at least about 98% homology
to nucleic acids of the invention. The terms "percent similarity",
"percent identity" and "percent homology" when referring to a
particular sequence are used as set forth in the University of
Wisconsin GCG software program. Nucleic acids of the invention also
include complementary nucleic acids. In some instances, the
sequences will be fully complementary (no mismatches) when aligned.
In other instances, there may be up to about a 20% mismatch in the
sequences.
[0086] Nucleic acids of the invention also include fragments of the
nucleic acids of the invention. A "fragment" refers to a nucleic
acid sequence that is preferably at least about 10 nucleic acids in
length, more preferably about 40 nucleic acids, and most preferably
about 100 nucleic acids in length. A "fragment" can also mean a
stretch of at least about 100 consecutive nucleotides that contains
one or more deletions, insertions, or substitutions. A "fragment"
can also mean the whole coding sequence of a gene and may include
5' and 3' untranslated regions.
[0087] Nucleic acids of the invention can be cloned into a vector.
A "vector" is a replicon, such as a plasmid, cosmid, bacmid, phage,
artificial chromosome (BAC, YAC) or virus, into which another
genetic sequence or element (either DNA or RNA) may be inserted so
as to bring about the replication of the attached sequence or
element. A "replicon" is any genetic element, for example, a
plasmid, cosmid, bacmid, phage, artificial chromosome (BAC, YAC) or
virus, that is capable of replication largely under its own
control. A replicon may be either RNA or DNA and may be single- or
double-stranded. In some embodiments, the expression vector
contains a constitutively active promoter segment (such as but not
limited to CMV, SV40, Elongation Factor or LTR sequences) or an
inducible promoter sequence such as the steroid inducible pIND
vector (Invitrogen), where the expression of the nucleic acid can
be regulated. Expression vectors of the invention may further
comprise regulatory sequences, for example, an internal ribosomal
entry site. The expression vector can be introduced into a cell by
transfection, for example.
[0088] Nucleic acids encoding antibodies of the invention may be
recombinantly expressed. The expression cells of the invention
include any insect expression cell line known, such as for example,
Spodoptera frugiperda cells. The expression cell lines may also be
yeast cell lines, such as, for example, Saccharomyces cerevisiae
and Schizosaccharomyces pombe cells. The expression cells may also
be mammalian cells such as, for example Chinese Hamster Ovary, baby
hamster kidney cells, human embryonic kidney line 293, normal dog
kidney cell lines, normal cat kidney cell lines, monkey kidney
cells, African green monkey kidney cells, COS cells, and
non-tumorigenic mouse myoblast G8 cells, fibroblast cell lines,
myeloma cell lines, mouse NIH/3T3 cells, LMTK cells, mouse sertoli
cells, human cervical carcinoma cells, buffalo rat liver cells,
human lung cells, human liver cells, mouse mammary tumor cells, TRI
cells, MRC 5 cells, and FS4 cells. Nucleic acids of the invention
may be introduced into a cell by transfection, for example.
Recombinantly expressed antibodies may be recovered from the growth
medium of the cells, for example.
[0089] Methods of Producing In-Out Antibodies to FRA
[0090] Immunizing Animals
[0091] The invention also provides methods of producing in-out
monoclonal antibodies that specifically bind to FRA. FRA may be
purified from cells or from recombinant systems using a variety of
well-known techniques for isolating and purifying proteins. For
example, but not by way of limitation, FRA may be isolated based on
the apparent molecular weight of the protein by running the protein
on an SDS-PAGE gel and blotting the proteins onto a membrane.
Thereafter, the appropriate size band corresponding to FRA may be
cut from the membrane and used as an immunogen in animals directly,
or by first extracting or eluting the protein from the membrane. As
an alternative example, the protein may be isolated by
size-exclusion chromatography alone or in combination with other
means of isolation and purification. Other means of purification
are available in such standard reference texts as Zola, MONOCLONAL
ANTIBODIES: PREPARATION AND USE OF MONOCLONAL ANTIBODIES AND
ENGINEERED ANTIBODY DERIVATIVES (BASICS: FROM BACKGROUND TO BENCH)
Springer-Verlag Ltd., New York, 2000; BASIC METHODS IN ANTIBODY
PRODUCTION AND CHARACTERIZATION, Chapter 11, "Antibody Purification
Methods," Howard and Bethell, Eds., CRC Press, 2000; ANTIBODY
ENGINEERING (SPRINGER LAB MANUAL.), Kontermann and Dubel, Eds.,
Springer-Verlag, 2001.
[0092] One strategy for generating in-out antibodies against FRA
involves immunizing animals with cells expressing FRA. Animals so
immunized will produce antibodies against the protein. Standard
methods are known for creating monoclonal antibodies including, but
are not limited to, the hybridoma technique (see Kohler &
Milstein, (1975) Nature 256:495-497); the trioma technique; the
human B-cell hybridoma technique (see Kozbor et al. (1983) Immunol.
Today 4:72) and the EBV hybridoma technique to produce human
monoclonal antibodies (see Cole, et al. in MONOCLONAL ANTIBODIES
AND CANCER THERAPY, Alan R. Liss, Inc., 1985, pp. 77-96).
[0093] Antibodies of the invention may be produced in vivo or in
vitro. For in vivo antibody production, animals are generally
immunized with an immunogenic portion of FRA. The antigen or
antigen-positive cell is generally combined with an adjuvant to
promote immunogenicity. Adjuvants vary according to the species
used for immunization. Examples of adjuvants include, but are not
limited to: Freund's complete adjuvant ("FCA"), Freund's incomplete
adjuvant ("FIA"), mineral gels (e.g., aluminum hydroxide), surface
active substances (e.g., lysolecithin, pluronic polyols,
polyanions), peptides, oil emulsions, keyhole limpet hemocyanin
("I(LH"), dinitrophenol ("DNP"), and potentially useful human
adjuvants such as Bacille Calmette-Guerin ("BCG") and
corynebacterium parvum. Such adjuvants are also well known in the
art.
[0094] Immunization may be accomplished using well-known
procedures. The dose and immunization regimen will depend on the
species of mammal immunized, its immune status, body weight, and/or
calculated surface area, etc. Typically, blood serum is sampled
from the immunized mammals and assayed for anti-FRA antibodies
using appropriate screening assays as described below, for
example.
[0095] Splenocytes from immunized animals may be immortalized by
fusing the splenocytes (containing the antibody-producing B cells)
with an immortal cell line such as a myeloma line. Typically,
myeloma cell line is from the same species as the splenocyte donor.
In one embodiment, the immortal cell line is sensitive to culture
medium containing hypoxanthine, aminopterin and thymidine ("HAT
medium"). In some embodiments, the myeloma cells are negative for
Epstein-Barr virus (EBV) infection. In preferred embodiments, the
myeloma cells are HAT-sensitive, EBV negative and Ig expression
negative. Any suitable myeloma may be used. Murine hybridomas may
be generated using mouse myeloma cell lines (e.g., the
P3-NS1/1-Ag4-1, P3-x63-Ag8.653 or Sp2/O-Ag14 myeloma lines). These
murine myeloma lines are available from the ATCC. These myeloma
cells are fused to the donor splenocytes polyethylene glycol
("PEG"), preferably 1500 molecular weight polyethylene glycol ("PEG
1500"). Hybridoma cells resulting from the fusion are selected in
HAT medium which kills unfused and unproductively fused myeloma
cells. Unfused splenocytes die over a short period of time in
culture. In some embodiments, the myeloma cells do not express
immunoglobulin genes.
[0096] Hybridomas producing a desired antibody which are detected
by screening assays such as those described below, may be used to
produce antibodies in culture or in animals. For example, the
hybridoma cells may be cultured in a nutrient medium under
conditions and for a time sufficient to allow the hybridoma cells
to secrete the monoclonal antibodies into the culture medium. These
techniques and culture media are well known by those skilled in the
art. Alternatively, the hybridoma cells may be injected into the
peritoneum of an unimmunized animal. The cells proliferate in the
peritoneal cavity and secrete the antibody, which accumulates as
ascites fluid. The ascites fluid may be withdrawn from the
peritoneal cavity with a syringe as a rich source of the monoclonal
antibody.
[0097] Another non-limiting method for producing human antibodies
is described in U.S. Pat. No. 5,789,650 which describes transgenic
mammals that produce antibodies of another species (e.g., humans)
with their own endogenous immunoglobulin genes being inactivated.
The genes for the heterologous antibodies are encoded by human
immunoglobulin genes. The transgenes containing the unrearranged
immunoglobulin encoding regions are introduced into a non-human
animal. The resulting transgenic animals are capable of
functionally rearranging the transgenic immunoglobulin sequences
and producing a repertoire of antibodies of various isotypes
encoded by human immunoglobulin genes. The B-cells from the
transgenic animals are subsequently immortalized by any of a
variety of methods, including fusion with an immortalizing cell
line (e.g., a myeloma cell).
[0098] In-out antibodies against FRA may also be prepared in vitro
using a variety of techniques known in the art. For example, but
not by way of limitation, fully human monoclonal antibodies against
FRA may be prepared by using in vitro-primed human splenocytes
(Boemer et al. (1991) J. Immunol. 147:86-95).
[0099] Alternatively, for example, the antibodies of the invention
may be prepared by "repertoire cloning" (Persson et al. (1991)
Proc. Nat. Acad. Sci. USA 88:2432-2436; and Huang and Stollar(1991)
J. Immunol. Methods 141:227-236). Further, U.S. Pat. No. 5,798,230
describes preparation of human monoclonal antibodies from human B
antibody-producing B cells that are immortalized by infection with
an Epstein-Barr virus that expresses Epstein-Barr virus nuclear
antigen 2 (EBNA2). EBNA2, required for immortalization, is then
inactivated resulting in increased antibody titers.
[0100] In another embodiment, in-out antibodies against FRA are
formed by in vitro immunization of peripheral blood mononuclear
cells ("PBMCs"). This may be accomplished by any means known in the
art, such as, for example, using methods described in the
literature (Zafiropoulos et al. (1997) J. Immunological Methods
200:181-190).
[0101] Another strategy for generating in-out antibodies against
FRA involves immunizing animals with peptides corresponding to
regions of the membrane bound form of FRA that allow for
internalization of antibodies that retain robust immune effector
activity. Animals so immunized will produce antibodies against the
protein. Standard methods are known for creating monoclonal
antibodies including, but are not limited to, the hybridoma
technique (see Kohler & Milstein, (1975) Nature 256:495-497);
the trioma technique; the human B-cell hybridoma technique (see
Kozbor et al. (1983) Immunol. Today 4:72) and the EBV hybridoma
technique to produce human monoclonal antibodies (see Cole, et al.
in MONOCLONAL ANTIBODIES AND CANCER THERAPY, Alan R. Liss, Inc.,
1985, pp. 77-96).
[0102] In one embodiment of the invention, the procedure for in
vitro immunization is supplemented with directed evolution of the
hybridoma cells in which a dominant negative allele of a mismatch
repair gene such as PMS1, PMS2, PMS2-134, PMSR2, PMSR3, MLH1, MLH2,
MLH3, MLH4, MLH5, MLH6, PMSL9, MSH1, and MSH2 is introduced into
the hybridoma cells after fusion of the splenocytes, or to the
myeloma cells before fusion. Cells containing the dominant negative
mutant will become hypermutable and accumulate mutations at a
higher rate than untransfected control cells. A pool of the
mutating cells may be screened for clones that produce higher
affinity antibodies, or that produce higher titers of antibodies,
or that simply grow faster or better under certain conditions. The
technique for generating hypermutable cells using dominant negative
alleles of mismatch repair genes is described in U.S. Pat. No.
6,146,894, issued Nov. 14, 2000. Alternatively, mismatch repair may
be inhibited using the chemical inhibitors of mismatch repair
described by Nicolaides et al. in WO 02/054856 "Chemical Inhibitors
of Mismatch Repair" published Jul. 18, 2002. The technique for
enhancing antibodies using the dominant negative alleles of
mismatch repair genes or chemical inhibitors of mismatch repair may
be applied to mammalian expression cells expressing cloned
immunoglobulin genes as well. Cells expressing the dominant
negative alleles can be "cured" in that the dominant negative
allele can be turned off, if inducible, eliminated from the cell
and the like such that the cells become genetically stable once
more and no longer accumulate mutations at the abnormally high
rate.
[0103] Screening for In-Out Antibodies
[0104] Screening for in-out antibodies that specifically bind to
FRA may be accomplished using an enzyme-linked immunosorbent assay
(ELISA), by screening antibodies for immune effector activity,
and/or by assaying for internalization. Antibodies exhibiting
immune effector activity may be identified using a standard immune
effector assay to monitor antibody-dependent cellular cytotoxicity
(ADCC) or complement-dependent cytotoxicity (CDC). Antibodies that
can be internalized can be identified by conjugating the antibody
with a detectable label, such as a fluorochrome or prodrug, to
monitor ability to internalize by visualization or toxicity. One or
more of these assays (ELISA, immune effector assay, and
internalization assay) may be performed in any order to identify
in-out antibodies of the invention.
[0105] For example, the ELISA may comprise coating microtiter
plates with immunizing antigen (whole protein or peptides).
Antibodies from positively reacting clones can be screened for
reactivity in an ELISA-based assay to FRA. Antibodies specific to
the alpha form of folate receptor can be identified by ELISA
employing one or more other isotypes of folate receptor. Clones
that produce antibodies that are reactive to FRA are selected for
further expansion and development. Confirmation of FRA-reactive
antibodies exhibiting in-out activity may be accomplished, for
example, using a standard immune effector assay to monitor
antibody-dependent cellular cytotoxicity (ADCC) or
complement-dependent cytotoxicity (CDC). FRA-specific antibodies
exhibiting immune effector activity can then be conjugated with a
fluorochrome or prodrug to monitor ability to internalize by
visualization or toxicity that occurs when prodrug is internalized
and liberated from the antibody leading to the presence of the
toxin.
[0106] Pharmaceutical Compositions of Antibodies
[0107] Another aspect of the invention features a pharmaceutical
composition of anti-FRA antibodies of the invention. The
pharmaceutical compositions may be used to inhibit or reduce growth
of FRA-positive cells in a patient. In certain embodiments, the
pharmaceutical composition is formulated for administration by
injection or infusion.
[0108] Pharmaceutical compositions of the invention may further
comprise one or more biomolecule, chemotherapeutic agent, or
antifolate compound. Examples of antifolate compounds include but
are not limited to 5-fluoro-2'-deoxy-uridine-5'-monophosphate
(FdUMP), 5-fluorouracil, leucovorin, ZD1649, MTA, GW1843U89,
ZD9331, AG337, and PT523. In some embodiments, the antibody is
conjugated to the biomolecule, antifolate compound, or
chemotherapeutic agent. Suitable chemotherapeutic agents include
but are not limited to a radioisotope, including, but not limited
to Lead-212, Bismuth-212, Astatine-211, Iodine-131, Scandium-47,
Rhenium-186, Rhenium-188, Yttrium-90, Iodine-123, Iodine-125,
Bromine-77, Indium-111 , and fissionable nuclides such as Boron-10
or an Actinide. In other embodiments, the agent is a toxin or
cytotoxic drug, including but not limited to ricin, modified
Pseudomonas enterotoxin A, calicheamicin, adriamycin,
5-fluorouracil, and the like.
[0109] Pharmaceutical compositions of the invention may be
formulated with a pharmaceutically acceptable carrier or medium.
Suitable pharmaceutically acceptable carriers include water, PBS,
salt solution (such as Ringer's solution), alcohols, oils,
gelatins, and carbohydrates, such as lactose, amylose, or starch,
fatty acid esters, hydroxymethylcellulose, and polyvinyl
pyrolidine. Such preparations can be sterilized, and if desired,
mixed with auxiliary agents such as lubricants, preservatives,
stabilizers, wetting agents, emulsifiers, salts for influencing
osmotic pressure, buffers, and coloring. Pharmaceutical carriers
suitable for use in the present invention are known in the art and
are described, for example, in Pharmaceutical Sciences (17.sup.th
Ed., Mack Pub. Co., Easton, Pa.).
[0110] Kits
[0111] According to yet another aspect of the invention, a kit is
provided for inhibiting or reducing growth of FRA-positive cells in
vitro or in vivo. Also provided are kits for identifying the
presence of FRA-positive cells in vitro or in vivo.
[0112] The kits of the invention comprise antibody or an antibody
composition of the invention and instructions for using the kit in
a method for inhibiting or reducing growth of FRA-positive cells,
preferably dysplastic cells, in vitro or in vivo or in a method for
identifying the presence of FRA-positive cells, preferably
dysplastic cells, in a biological sample. The kit may comprise at
least one biomolecule, antifolate compound, or chemotherapeutic
agent. The kit may comprise at least one diagnostic reagent. An
example of a diagnostic reagent is a detectable label, for example
but not limited to a radioactive, fluorescent, or chromophoric
agent (e.g., .sup.111In-DOTA). The detectable label may comprise an
enzyme. The kit may comprise instructions and/or means for
administering the antibody or antibody composition, for example, by
injection or infusion.
[0113] Methods of Detecting a FRA-Positive Cell
[0114] The methods of the invention include methods of detecting
cells, such as dysplastic cells, presenting FRA on the surface,
including but not limited to ovarian, pancreatic, prostate, or lung
cancer cells. The method may be performed in vitro on a biological
sample or in vivo. Methods of detecting FRA-positive cells
according to the invention comprise contacting anti-FRA antibody of
the invention with a biological sample or administering anti-FRA
antibody of the invention to a patient, wherein the antibody is
labeled with a detectable label, for example but not limited to a
radioactive, fluorescent, or chromophoric agent (e.g.,
.sup.111In-DOTA), and determining binding of the antibody to cells.
The detectable label may be an enzyme.
[0115] Methods of Reducing the Growth of FRA-Positive Cells
[0116] The in-out anti-FRA antibodies of the invention are suitable
for use in reducing the growth of FRA-positive cells in vitro or in
vivo. The methods of the invention are suitable for use in humans
and non-human animals identified as having a neoplastic condition
associated with an increased expression of FRA. Non-human animals
which benefit from the invention include pets, exotic (e.g., zoo
animals) and domestic livestock. Preferably the non-human animals
are mammals.
[0117] The invention is suitable for use in a human or animal
patient that is identified as having a dysplastic disorder that is
marked by increased expression of FRA in the neoplasm in relation
to normal tissues. Once such a patient is identified as in need of
treatment for such a condition, the method of the invention may be
applied to effect treatment of the condition. Dysplastic tissues
that may be treated include, but are not limited to ovary, lung,
pancreas, and prostate.
[0118] The antibodies and derivatives thereof for use in the
invention may be administered orally in any acceptable dosage form
such as capsules, tablets, aqueous suspensions, solutions or the
like. The antibodies and derivatives thereof may also be
administered parenterally. That is via the following routes of
administration: subcutaneous, intravenous, intramuscular,
intra-articular, intra-synovial, intrastemal, intranasal,
topically, intrathecal, intrahepatic, intralesional, and
intracranial injection or infusion techniques. Generally, the
antibodies and derivatives will be provided as an intramuscular or
intravenous injection.
[0119] The antibodies and derivatives of the invention may be
administered alone or with a pharmaceutically acceptable carrier,
including acceptable adjuvants, vehicles and excipients.
[0120] The antibodies and derivatives of the invention may also be
administered with one or more antifolate compounds. The antifolate
compounds include, but are not limited to
5-fluoro-2'-deoxy-uridine-5'-monophosphate (FdUMP); 5-fluorouracil
(5-FU); L-5-formyltetrahydrofolate ("leucovorin");
N-[5-(N-(3,4-dihydro-2-methyl-4-oxoquinazolin-6-yl-methyl)-amino)-2-theny-
l)]-L-glutamic acid ("ZD1649"; also known as "Tomudex") (Jackman et
al. (1991) Cancer Res. 51:5579-5586);
N-(4-(2-(2-amino-4,7-dihydro-4-oxo-3H-pyrrolo[2,3-D]pyrimidin-5-yl)-ethyl-
)-benzoyl]-L-glutamic acid ("multi-targeted antifolate" (MTA) also
known as "LY231514," "ALIMTA," and "Pemetrexed")(Taylor et al.
(1992) J. Med. Chem. 35:4450-4454; Shih et al. (1997) Cancer Res.
57:1116-1123);
(S)-2-(5)-(((1,2-dihydro-3-methyl-1-oxobenzo(f)quinazolin-9-yl)-methyl)-a-
mino)-oxo-2-isoindolinyl)-glutaric acid ("GW1843U89") (Hanlon and
Ferone (1996) Cancer Res. 56:3301-3306);
(2S)-2-{O-fluoro-p-[N-(2,7-dimethyl-4-oxo-3,4-dihydro-quinazolin-6-yl-met-
hyl)-N-prop-2-ynyl)amino]benzamido}-4-(tetrazol-5-yl)-butyric acid
("ZD9331") (Jackman et al. (1997) Clin. Cancer Res. 3:911-921);
3,4-dihydro-amino-6-methyl-4-oxo-5-(4-pyridylthio)-quinazoline
("AG337" also known as "Thymitaq") (Webber et al. (1996) Cancer
Chemother. Pharmacol. 37:509-517; Rafi et al. (1998) J. Clin.
Oncol. 16:1331-1341), and
N.sup..alpha.-(4-amino-4-deoxypteroyl)-N.sup..delta.-(hemiphthaloyl-L-
-omithine) ("PT523") (Rhee et al. (1994) Mol. Pharmacol.
45:783-791; Rowowsky (1999) Curr. Med. Chem. 6:329-352). The
antifolate compounds may be administered before, after, or
simultaneously with the anti-FR-.alpha. antibodies of the
invention. The amounts of antifolate compounds to be administered
may be the dosages currently used, or may be increased or
decreased, as can readily be determined by a physician based on
achieving decreased tumor growth or tumor elimination without
causing any untoward effects on the patient.
[0121] The antibodies of the invention may be administered before,
after, or simultaneously with another therapeutic or diagnostic
agent. For example, the in-out antibodies of the invention may be
administered alone or with a cytotoxic agent such as but not
limited to adriamycin, doxorubicin, gemcitabine, or 5-fluorouracil.
The in-out antibodies of the invention may be administered alone or
with a cytostatic agent such as but not limited to tarceva and
avastin. The in-out antibodies and derivatives of the invention may
be administered alone or with a vaccine agent. The in-out
antibodies and derivatives of the invention may be administered
alone or with another biomolecule such as but not limited to
interleukin-2, interferon alpha, interferon beta, interferon gamma,
rituxan, zevalin, herceptin, erbitux, avastin.
[0122] The in-out antibodies and derivatives of the invention may
be administered as a homogeneous mixture of unconjugated or
conjugated antibody or as a heterogeneous mixture of unconjugated
and conjugated in-out antibody.
[0123] The effective dosage will depend on a variety of factors and
it is well within the purview of a skilled physician to adjust the
dosage for a given patient according to various parameters such as
body weight, the goal of treatment, the highest tolerated dose, the
specific formulation used, the route of administration and the
like. Generally, dosage levels of between about 0.001 and about 100
mg/kg body weight per day of the antibody or derivative thereof are
suitable. In some embodiments, the dose will be about 0.1 to about
50 mg/kg body weight per day of the antibody or derivative thereof.
In other embodiments, the dose will be about 0.1 mg/kg body
weight/day to about 20 mg/kg body weight/day. In still other
embodiments, the dose will be about 0.1 mg/kg body weight/day to
about 10 mg/kg body weight/day. Dosing may be as a bolus or an
infusion. Dosages may be given once a day or multiple times in a
day. Further, dosages may be given multiple times of a period of
time. In some embodiments, the doses are given every 1-14 days. In
some embodiments, the antibodies or derivatives thereof are given
as a dose of about. 3 to 1 mg/kg i.p. In other embodiments, the
antibodies of derivatives thereof are provided at about 5 to 12.5
mg/kg i.v. In still other embodiments, the antibodies or
derivatives thereof are provided such that a plasma level of at
least about 1 ug/ml is maintained.
[0124] Effective treatment may be assessed in a variety of ways. In
one embodiment, effective treatment is determined by a slowed
progression of tumor growth. In other embodiments, effective
treatment is marked by shrinkage of the tumor (i.e., decrease in
the size of the tumor). In other embodiments, effective treatment
is marked by inhibition of metastasis of the tumor. In still other
embodiments, effective therapy is measured by increased well-being
of the patient including such signs as weight gain, regained
strength, decreased pain, thriving, and subjective indications from
the patient of better health.
[0125] The following Examples are provided to illustrate the
present invention, and should not be construed as limiting
thereof.
EXAMPLES
Example 1
In-Out Antibodies That Can Bind to FRA
[0126] The monoclonal antibody ML-1 was developed by grafting the
CDRs of the variable domain of a murine antibody specific to FRA
onto a human IgG1 constant region. The antibody was shown to bind
specifically to FRA protein and cancer cells expressing FRA and was
found to have a binding constant of about 5 nM using Biacore.RTM..
To demonstrate FRA-specific binding, antigen-specific ELISA were
performed using recombinant FRA in 96-well format following methods
used by those skilled in the art (FIG. 1A). Antibodies found to
react by ELISA were further analyzed for FRA binding using FACS
analysis following the manufacturer's protocol. Shown in FIG. 1B
are representative data of the FACS analysis whereby FRA-expressing
ovarian tumor cells were positive for ML-1 binding in contrast to
null cells. Antigen-specific ELISA can be also formatted using
whole cells expressing FRA, membrane preparations obtained from
such FRA expressing cells, or synthetic, overlapping peptides
encompassing the entire FRA amino acid sequence.
Example 2
[0127] Activity of ML-1 antibody for immune effector activity was
assessed by standard antibody-dependent cellular cytotoxicity
(ADCC) assays on the FRA-expressing OVCAR-3 cell line. Briefly,
OVCAR-3 target cells are seeded in flat-bottom 96-well microplates
in complete growth medium (RPMI-1640 containing 10% FBS, 2 mM
L-glutamine). The following day, the complete medium is replaced
with 100 ul of CHO-CD serum-free medium (Sigma) and 50 ul of
antibody-containing conditioned medium is added to target cells and
incubated for 20 minutes at 37.degree. C. Subsequently, 100 ul of
serum-free medium containing 2.times.10.sup.5 effector cells are
added to each well and cells are incubated for 5-6 hours at
37.degree. C., 5% CO.sub.2. Effector cells are derived from human
peripheral blood mononuclear cells (PBMCs), isolated from healthy
donors (purchased from Interstate Blood Bank). Prior to use in
ADCC, PBMCs are activated by seeding PBMCs at 2.5.times.10.sup.6/ml
in complete RPMI containing about 10 ng/ml human recombinant
interleukin 2 (R&D Systems) for 3 days at 37.degree. C., 5%
CO.sub.2. Activated PBMCs are then added to OVCAR-3 cells at an
effector:target cell ratio of 5:1 and cultures are incubated for
5-6 hours at 37.degree. C., 5% CO.sub.2. Supernatant is then
collected from each well and transferred into ELISA plates and
analyzed for ADCC as follows. ADCC is monitored by lactate
dehydrogenase (LDH) release, an endogenous enzyme used to measure
ADCC in standard assays. LDH is monitored by adding 100 ul of LDH
substrate (Roche), a chemical that when converted by LDH is
spectrophotometrically detectable at OD.sub.490, to supernatant and
incubated for 10 minutes at ambient temperature. LDH activity is
proportional to the extent of the LDH enzyme released from lysed
target cells. Optical density at 490 nm (OD.sub.490) is obtained
spectrophotometrically. 2% Triton X is added to effector cells
alone as a "max" positive control, while target cells with PBMC and
no antibody serve as the "spontaneous" negative control. LDH values
are obtained and percent of cytotoxicity is determined with the
formula: (sample value-spontaneous)/(max-spontaneous).times.100%,
where `spontaneous`=target cell lysis in absence of effector cells,
and `max`=target cell lysis in the presence of 2% Triton.
Cytotoxicity elicited by 100 ng/ml of MORAb-A92 (protein A
purified) will be used as positive control. Non-specific
cytotoxicity will be monitored using 100 ng/ml of normal human IgG1
antibody. The ratio obtained by dividing the % cytotoxicity by the
concentration of the antibody for each well/clone (i.e.
ratio=50(%)/100(ng/ml)=0.5) will be set as the criterion for
selecting lead clones with potentially enhanced effector
function.
[0128] Analysis of ML-1 shows the ability to enhance ADCC activity
(p=0.018) over cells incubated with control Ig or no antibody (FIG.
2). FIG. 2 demonstrates that ML-1 elicits a robust
antibody-dependent cellular cytotoxicity (ADCC) activity. Tumor
cell line OVCAR3 (referred to as target) which expresses FRA was
incubated with human PBMCs alone (no Ab lane); with ML-1; or
control Ig (normal IgG). Cell cultures were assayed for killing by
monitoring for lactate dehydrogenase (LDH) release that occurs upon
cell lysis. ML-1 has ADCC activity on FRA-expressing cells. These
data support the finding that ML-1 has cytotoxic effects via immune
effector function.
Example 3
[0129] ML-1 internalizes when bound to FRA-expressing cells. This
finding is shown in FIG. 3 using the Hum-ZAP assay. Second
immunotoxins are conjugations of a secondary antibody to the
ribosome inactivating protein saporin. If the primary antibody
being tested is internalized, the saporin is transported into the
cell via its binding to the secondary antibody. Once internalized
saporin separates from its IgG conjugate, it inhibits protein
synthesis and ultimately causes cell death. Hum-ZAP (Advanced
Targeting Systems, cat# IT-22) is a secondary chemical conjugate of
affinity purified goat anti-human IgG, (mw 210 kDa) that recognizes
human monoclonal antibodies. The control molecule, Goat IgG-SAP
(Advanced Targeting Systems cat#IT-19) is a conjugate of normal
goat IgG and saporin. Briefly, cells are plated into flat-bottom
96-well tissue culture plates at 2500/well in 80 ul of RPMI 1640
with 10% FCS, 2.0 mM glutamine, 1.0 mM sodium pyruvate, and 0.1 mM
MEM non-essential amino acids. Twenty-four hours later, 10 ul of
primary antibodies ML-1 or MORAb-A92 are added along with 10 ul of
Hum-ZAP or Goat IgG-SAP to bring the total volume to 100 ul.
Experiments are set up with antibody titrations and include primary
and secondary antibodies alone as control. Four days later, cell
viability is evaluated using Promega CellTiter.RTM. Cytotoxicity
Assay (cat# G3581) which reads viable cell number by
spectrophotometry. All tests are performed in triplicate. Data is
evaluated by comparing treated and untreated wells and results are
expressed as percent of control. As shown in FIG. 3, ML-1
internalizes in OVCAR-3 cells which overexpress FRA. Cells die upon
treatment with ML-1 linked to saporin (diamond) in contrast to ML-1
unconjugated (square), while an isotype control antibody MORAb-A92
did not kill cells in conjugated or unconjugated toxin form
(triangle and X, respectively). As control, cells not expressing
FRA were used and it was shown that ML-1 has no toxic effect in
toxin-conjugated or unconjugated form. These data support the
finding that ML-1 internalizes in FRA-bearing cells.
Sequence CWU 1
1
2 1 696 DNA Homo sapiens 1 attgcatggg ccaggactga gcttctcaat
gtctgcatga acgccaagca ccacaaggaa 60 aagccaggcc ccgaggacaa
gttgcatgag cagtgtcgac cctggaggaa gaatgcctgc 120 tgttctacca
acaccagcca ggaagcccat aaggatgttt cctacctata tagattcaac 180
tggaaccact gtggagagat ggcacctgcc tgcaaacggc atttcatcca ggacacctgc
240 ctctacgagt gctcccccaa cttggggccc tggatccagc aggtggatca
gagctggcgc 300 aaagagcggg tactgaacgt gcccctgtgc aaagaggact
gtgagcaatg gtgggaagat 360 tgtcgcacct cctacacctg caagagcaac
tggcacaagg gctggaactg gacttcaggg 420 tttaacaagt gcgcagtggg
agctgcctgc caacctttcc atttctactt ccccacaccc 480 actgttctgt
gcaatgaaat ctggactcac tcctacaagg tcagcaacta cagccgaggg 540
agtggccgct gcatccagat gtggttcgac ccagcccagg gcaaccccaa tgaggaggtg
600 gcgaggttct atgctgcagc catgagtggg gctgggccct gggcagcctg
gcctttcctg 660 cttagcctgg ccctaatgct gctgtggctg ctcagc 696 2 232
PRT Homo sapiens 2 Ile Ala Trp Ala Arg Thr Glu Leu Leu Asn Val Cys
Met Asn Ala Lys 1 5 10 15 His His Lys Glu Lys Pro Gly Pro Glu Asp
Lys Leu His Glu Gln Cys 20 25 30 Arg Pro Trp Arg Lys Asn Ala Cys
Cys Ser Thr Asn Thr Ser Gln Glu 35 40 45 Ala His Lys Asp Val Ser
Tyr Leu Tyr Arg Phe Asn Trp Asn His Cys 50 55 60 Gly Glu Met Ala
Pro Ala Cys Lys Arg His Phe Ile Gln Asp Thr Cys 65 70 75 80 Leu Tyr
Glu Cys Ser Pro Asn Leu Gly Pro Trp Ile Gln Gln Val Asp 85 90 95
Gln Ser Trp Arg Lys Glu Arg Val Leu Asn Val Pro Leu Cys Lys Glu 100
105 110 Asp Cys Glu Gln Trp Trp Glu Asp Cys Arg Thr Ser Tyr Thr Cys
Lys 115 120 125 Ser Asn Trp His Lys Gly Trp Asn Trp Thr Ser Gly Phe
Asn Lys Cys 130 135 140 Ala Val Gly Ala Ala Cys Gln Pro Phe His Phe
Tyr Phe Pro Thr Pro 145 150 155 160 Thr Val Leu Cys Asn Glu Ile Trp
Thr His Ser Tyr Lys Val Ser Asn 165 170 175 Tyr Ser Arg Gly Ser Gly
Arg Cys Ile Gln Met Trp Phe Asp Pro Ala 180 185 190 Gln Gly Asn Pro
Asn Glu Glu Val Ala Arg Phe Tyr Ala Ala Ala Met 195 200 205 Ser Gly
Ala Gly Pro Trp Ala Ala Trp Pro Phe Leu Leu Ser Leu Ala 210 215 220
Leu Met Leu Leu Trp Leu Leu Ser 225 230
* * * * *