U.S. patent application number 10/104607 was filed with the patent office on 2003-05-15 for combination treatment of pancreatic cancer.
Invention is credited to Caplin, Martyn, Gevas, Philip C., Grimes, Stephen, Michaeli, Dov.
Application Number | 20030091574 10/104607 |
Document ID | / |
Family ID | 23064442 |
Filed Date | 2003-05-15 |
United States Patent
Application |
20030091574 |
Kind Code |
A1 |
Gevas, Philip C. ; et
al. |
May 15, 2003 |
Combination treatment of pancreatic cancer
Abstract
A combination for use in the treatment of pancreatic cancer
comprising: (i) an anti-gastrin effective immunogenic composition;
and, (ii) one or more chemotherapeutic agents suitable for
inhibiting cancer growth.
Inventors: |
Gevas, Philip C.; (Key
Biscayne, FL) ; Michaeli, Dov; (Larkspur, CA)
; Grimes, Stephen; (Davis, CA) ; Caplin,
Martyn; (London, GB) |
Correspondence
Address: |
WHITE & CASE LLP
PATENT DEPARTMENT
1155 AVENUE OF THE AMERICAS
NEW YORK
NY
10036
US
|
Family ID: |
23064442 |
Appl. No.: |
10/104607 |
Filed: |
March 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60278294 |
Mar 23, 2001 |
|
|
|
Current U.S.
Class: |
424/155.1 ;
424/649; 514/251; 514/269; 514/283; 514/34; 514/50 |
Current CPC
Class: |
C07K 16/26 20130101;
A61P 43/00 20180101; A61K 39/0005 20130101; A61P 35/00 20180101;
A61K 39/00113 20180801; A61K 2039/505 20130101; A61K 39/001103
20180801; A61K 2039/6037 20130101; A61P 35/04 20180101 |
Class at
Publication: |
424/155.1 ;
424/649; 514/34; 514/283; 514/251; 514/269; 514/50 |
International
Class: |
A61K 039/395; A61K
031/7072; A61K 031/704; A61K 031/525; A61K 033/24; A61K 031/513;
A61K 031/4745 |
Claims
What is claimed is:
1. A combination for use in the treatment of pancreatic cancer
comprising: (i) an anti-gastrin effective immunogenic composition;
and, (ii) one or more chemotherapeutic agents suitable for
inhibiting cancer growth.
2. The combination of claim 1 wherein the anti-gastrin effective
immunogenic composition is selected from immunogens comprising an
epitope of the gastrin peptide G17 covalently linked through a
spacer peptide to an immunogenic protein or fragment thereof.
3. The combination of claim 1, which further comprises an
anti-CCKB/gastrin receptor peptide GRE1 or peptide GRE4 effective
immunogenic composition.
4. The combination of claim 1 wherein one more chemotherapeutic
agent is selected from the group consisting of docetaxel,
leucovorin/5-fluorouraci- l, gemcitabine, cisplatin and
irinotecan.
5. The combination of claim 1 wherein the effective immunogenic
composition comprises a conjugate of the aminoterminal G17 peptide
epitope covalently linked to a seven-amino acid/peptide spacer
which is attached to an .epsilon.-amino acid of the side chain of
the immunogenic carrier protein lysine residue.
6. The combination of claim 3, wherein the effective immunogenic
composition comprises a conjugate of the aminoterminal
CCK-B/gastric receptor peptide which is attached to an
.epsilon.-amino acid side chain of the immunogenic carrier protein
lysine residue.
7. The combination of claim 1 wherein the immunogenic composition
is formulated in a water-in-oil emulsion suitable for intramuscular
injection.
8. The combination of claim 1, wherein the immunogenic composition
ranges from 10 .mu.g to 5000 .mu.g of the immunogen per dose.
9. The combination of claim 1 wherein the chemotherapeutic agent is
gemcitabine at a dose ranging from 500-1400 mg/m.sup.2 weekly for 3
weeks, every 28 days.
10. The combination of claim 1 or 6 wherein the immunogenic
composition is about 250 .mu.g to 500 .mu.g per dose.
11. The combination of claim 1 wherein the chemotherapeutic agent
is irinotecan.
12. A combination for use in the treatment of pancreatic cancer
comprising: (i) an anti-gastrin and/or anti-gastrin receptor
effective immunological agent which can be monoclonal antibody or
polyclonal antibodies derived from antisera produced in a patient
by immunization with an anti-gastrin immunogenic composition; and
(ii) one or more chemotherapeutic agents suitable for inhibiting
cancer growth.
13. The combination as claimed in claims 1 or 12, wherein the
treatment prevents cancer cell metastasis.
14. A method for treating pancreatic cancer comprising
administering a gastrin-immunoneutralizing immunogenic composition;
and administering a pharmaceutical composition of one or more
chemotherapeutic agent effective for inhibiting cancer growth.
15. The method of claim 14 wherein the immunogenic composition
comprising an immunogen directed to eliciting neutralizing
antibodies against gastrin G17, Gly-G17, CCK-B/gastrin receptor
peptide GRE1 or GRE4.
16. The method of claim 14 wherein one or more chemotherapeutic
agent is selected from a group consisting of docetaxel,
leucovorin/5-fluorouracil, gemcitabine, cisplatin and
irinotecan.
17. The method of claim 14, wherein the chemotherapeutic agent is
gemcitabine.
Description
[0001] This application claims the benefit of U.S. provisional
patent application No. 60/278,294 filed Mar. 23, 2001.
FIELD OF THE INVENTION
[0002] The invention relates to a combination of immunological and
chemotherapeutic treatment of pancreatic cancer. In particular,
treatment of locally advanced or metastatic gastrin-dependent
pancreatic adenocarcinoma in the form of immunization is provided
against gastrin hormone in combination with one or more anti-cancer
drugs.
BACKGROUND OF THE INVENTION
[0003] In 1998, approximately 29,000 people in the United States
were diagnosed with pancreatic adenocarcinoma, and approximately
28,900 people were expected to die from this tumor .sup.[1]. The
overall cure rate for pancreatic cancer remains less than 5%
despite more than 20 years of clinical trials. Only 10% of subjects
have a potentially resectable tumor; however, even for subjects
undergoing a curative pancreaticoduodenectomy, five-year survival
is 6-24% .sup.[2]. The vast majority of subjects have unresectable
tumors and develop metastatic disease within the first year of
therapy. The median survival for subjects with metastatic disease
is 3-6 months.
[0004] The description of cancertrophic agents set forth below
includes both growth factor and growth factor receptors which are
surprisingly expressed or overexpressed in cancerous tumors or more
specifically cancer cells.
[0005] Gastrin is highly expressed in the antral mucosa and
duodenal bulb and expressed at low levels in a variety of tissues,
including the pancreas. Gastrin is also highly expressed in the
fetal pancreas, a fact which may be of significance in the
development of pancreatic neoplasms .sup.[3].
[0006] The normal nonfetal pancreas shows no expression of gastrin
isoforms or receptor. It has been shown that a large percentage of
patients with pancreatic cancer possess progastrin,
glycine-extended gastrin, amidated gastrin in their blood, and
CCK-B/gastrin receptor are present in the tumor cells.sup.[4].
Thus, it was later found that pancreatic adenocarcinoma expresses
the precursor forms of gastrin, especially the progastrin and
glycine-extended forms. The tumor cells were also determined to
express the CCK-B/gastrin receptor. Similarly, these precursor
gastrin forms and receptors were detected in other cancers, such as
gastric, colonic, and hepatocellular carcinomas.
[0007] Several growth factors have been postulated to affect the
growth and development of pancreatic cancer. Moreover, it is well
recognized that gastrin is a trophic hormone and promotes growth of
gastrointestinal (GI) and non-gastrointestinal cancers .sup.[4].
Gastrin has been shown to promote the growth of hepatocellular
carcinoma, renal cell carcinoma, small cell carcinoma of the lung
and also pancreatic carcinoma .sup.[6-9]. Gastrin affects cell
behavior in the form of circulating fully processed peptides as
well as autocrine process whereby incomplete processed precursor
gastrin, especially in the form of glycine-extended gastrin can
stimulate cell growth or cell function.sup.[10].
[0008] In particular, a number of investigations have shown the
important role that G17 gastrin and glycine-extended G17 (Gly-G17)
gastrin play in the proliferation of gastrointestinal
adenocarcinomas including pancreatic adenocarcinoma. It has been
demonstrated that G17 gastrin causes proliferation of a variety of
colorectal, gastric and pancreatic cancer cell lines, both in vitro
and in vivo .sup.[11][12][6][13] and that an autocrine pathway may
be involved .sup.[14] [15]. Gly-G17 gastrin has also been shown to
stimulate growth of various cancers via an autocrine/paracrine
pathway.sup.[16][17].
[0009] Gastrin is actually a family of peptides including G17
gastrin, G34 gastrin, and the immature forms, glycine-extended G17
(Gly-G17) gastrin and glycine-extended G34 (Gly-G34) gastrin. G17
and G34 share a 5-amino-acid carboxy-terminal sequence in common
with cholecystokinin (CCK). It has been shown that in this sequence
that interacts with the CCK-B/gastrin receptor .sup.[11][18].
[0010] Gastrin requires post-translational carboxy-terminal
alpha-amidation using glycine as the amide donor. The penultimate
intermediate is gastrin with a C-terminal glycine--the so-called
glycine-extended gastrins (Gly-G17 and Gly-G34). Similar
concentrations of glycine-extended forms and mature gastrins are
often found. Gly-G17 appears to have some of gastrin's biological
activities .sup.[17].
[0011] Different tissues exhibit different patterns of
post-translational gastrin modification resulting in the
accumulation of different intermediates. While gastrin produced by
the gastric antrum is largely fully amidated G17 .sup.[19],
anterior pituitary corticotrophs almost entirely fail to process
the amidation site, resulting in>99% glycine-extended gastrins.
In neonatal pancreatic cells, gastrin is largely in the G34 form
.sup.[19] and it is fully sulfated at Tyr29, a unique modification,
making it CCK-like in its potency .sup.[3]. In neoplastic tissue,
immature forms of gastrin typically predominate. In colorectal
carcinomas, a considerable amount of progastrin species accumulates
.sup.[20][21]. In rat pancreatic tumor AR42J, it has been reported
that only glycine-extended gastrins are present .sup.[17]. Nothing
has been reported on the forms of gastrin produced by human
pancreatic cancer cells.
[0012] The gastrin and CCK-B receptors were recently cloned and
shown to be identical .sup.[22]. Messenger RNA for CCK-B receptors
was detected in all pancreatic cancer cell lines of ductal origin
and in normal pancreatic tissue as well as in fresh tumor cells
.sup.[23][24][25] and may be over-expressed in malignant pancreatic
tissue in comparison with normal tissue .sup.[26]. Some authors
have detected CCK-B receptors using radiolabeled ligand binding
(either gastrin or CCK) technologies in both normal pancreas and
tumor cell lines..sup.[27] Others have failed to detect receptors
in the tumor cell lines but do detect them in normal tissue
.sup.[28][29].
[0013] MacKenzie et al .sup.[30] demonstrated by
radioligand-binding the abundant presence of CCK-B/gastrin receptor
on the rat pancreatic tumor cell line, AR42J. Tarasova et al
.sup.[31] have shown that following ligand binding assays, rapid
clustering and internalization of the CCK-B/gastrin receptor
occurred in the pancreatic tumor cell line AR42J, as well as in a
variety of human gastric and colorectal tumor cell lines.
Incubation of the CCK-B/gastrin receptor with 1 nM of the specific
inhibitor CI-988 inhibited the proliferation of gastrin-stimulated
(1 nM) AR42J cells by about 47% after 96 hours of treatment, which
is consistent with competitive inhibition of the gastrin receptor
.sup.[32]. Anti-G17 antibodies have been shown to inhibit the
binding of gastrin to the CCK-B/gastrin receptors on the pancreatic
tumor cell line AR42J.
[0014] It has been shown that gastrin peptides increase the
proliferation of GI cancer cell lines of human and animal origin
both in vitro and in vivo .sup.[5]. More recent studies with four
human pancreatic cell lines have shown that all proliferation was
increased by 40-68% G17 gastrin relative to untreated controls.
Studies with receptor antagonists showed that this proliferative
effect was mediated via the CCK-B receptor .sup.[11]. Other studies
have reported similar results .sup.[12], but not all studies report
a positive effect even if the presence of CCK-B receptors was
confirmed by binding studies .sup.[25].
[0015] Additional studies compared the mitogenic effects of gastrin
on colorectal and gastric tumor cells obtained from cancer subjects
at surgical resection. It was shown that cells from 69% of gastric
and 55% of colorectal tumors had an enhanced proliferation in
response to G17 gastrin, which was of greater magnitude than that
seen in normal cells obtained from the GI mucosa .sup.[33][34].
[0016] It has been shown that the gastrin gene is activated in
epithelial cells derived from GI tumor specimens, but not in normal
GI mucosal cells .sup.[35][36][37][21][17][38]. Malignant
epithelial cells have been shown to produce mitogenic gastrin
peptides, which can increase self-proliferation of the surrounding
cells, thereby inducing a state of tumor autonomy
.sup.[39][16].
[0017] Gastrin also stimulated in vivo tumor growth in mice
inoculated with human Panc-1 cells. Tumor volume in mice treated
with pentagastrin was 127% greater than untreated control tumors,
while those animals receiving a CCK-B receptor antagonist (without
pentagastrin) had tumors only 60% as large as controls
.sup.[11].
[0018] The stimulatory effect of gastrin was also demonstrated by
antisense RNA directed at gastrin .sup.[40] which suppressed the
growth of human pancreatic cell lines. The observation that gastrin
mRNA is detectable in all normal as well as tumor cell lines and in
fresh pancreatic tissue, while gastrin peptide is detectable only
in malignant tissue, suggested that gastrin mRNA may be translated
only in the tumor cells .sup.[15].
[0019] Although inactive in stimulating acid secretion, Gly-G17
gastrin has been shown to increase the proliferation of pancreatic
.sup.[41] cancer cells, G17 and Gly-G17 were found to be equipotent
in stimulating proliferation of rat pancreatic tumor AR42J
cells.
[0020] The normal physiological functions of gastrin are mediated
by CCK-B/gastrin receptors. Expression of the receptor occurs in
all types of gastrointestinal malignancies including colorectal,
gastric, pancreatic, hepatomas and colorectal liver metastases
.sup.[42][43][24][15] [44][45][46]. Different isoforms of the
receptor exist .sup.[51][52], and more than one isoform of the
CCK-B gastrin receptor may be co-expressed on individual cells.
Therefore, antagonism of CCK-B receptors may not be the optimal
method to suppress the proliferative action of gastrin present
either in the serum or produced locally by the tumor cells.
[0021] It has been shown that several types of tumors, e.g.,
colorectal, stomach, pancreatic and hepatocellular adenocarcinomas,
possess CCK-B/gastrin receptors in their plasma membranes and that
they respond to gastrin with powerful cellular proliferation
.sup.[53][13]. Furthermore, more recently it has been discovered
that many of these cancer cells also secrete gastrin and thus
effect an autonomous proliferative pathway .sup.[21][37][16].
[0022] The CCK-B/gastrin receptor belongs to a family of G
protein-coupled receptors with seven transmembrane domains with
equal affinity for both CCK and gastrin .sup.[54]. This receptor
was named a CCK type-B receptor because it was found predominantly
in the brain .sup.[55]. The receptor was subsequently found to be
identical to the peripheral CCK/gastrin receptor in the parietal
and ECL cells of the stomach .sup.[56]. This receptor has been well
characterized in a number of normal .sup.[57][58] and tumor tissues
.sup.[59][34], and extensively studied using the rat pancreatic
adenocarcinoma cell line AR42J .sup.[60]. The AR42J CCK-B/gastrin
receptor cDNA has been cloned and sequenced, and it is more than
90% homologous in DNA sequence to the CCK-B/gastrin receptor in rat
and human brain, and more than 84% homologous in sequence to the
canine parietal cell CCK-B/gastrin receptor cDNA .sup.[61],
demonstrating a high sequence homology even between species.
[0023] The peptide hormones G17 and G34 bind to the CCK-B/gastrin
receptor on the cell membrane of normal cells. However, it has been
found that G17, and not G34, stimulates the growth of
gastrin-dependent cancer cells. Serum-associated G17, in
particular, has the potential to stimulate the growth of colorectal
tumors in an endocrine manner mediated by CCK-B/gastrin receptors
.sup.[34] in the tumor cells. Gastrin-17 appears to be particularly
implicated in stimulating the growth of colorectal adenocarcinomas
due to a possible increased affinity for the CCK-B/gastrin receptor
on the tumor cells, over other gastrin hormone species .sup.[62].
The CCK-B/gastrin receptors were found to be expressed in a high
affinity form on 56.7% of human primary colorectal tumors
.sup.[53]. It has been postulated that a potential autocrine loop
may also exist due to endogenous production of precursor gastrin
peptides by such tumors .sup.[21]. The resulting G17
ligand/receptor complex stimulates cell growth by way of secondary
messengers for regulating cell function .sup.[63]. The binding of
G17 to the CCK-B/gastrin receptor leads to activation of
phosphatidyl inositol breakdown, protein kinase C activation with a
resultant increase in intracellular calcium ion concentration, as
well as the induction of c-fos and c-jun genes via
mitogen-activated protein kinase, which has been implicated in the
regulation of cell proliferation .sup.[64]. Additionally, gastrin
binding to the CCK-B/gastrin receptor has been associated with the
subsequent increase in phosphorylation by a tyrosine kinase,
pp125FADK (focal adhesion kinase), which may also have a role in
the transmission of mitogenic signals .sup.[65].
[0024] A number of high affinity CCK-B/gastrin receptor antagonists
have been evaluated therapeutically both in vitro and in vivo in a
number of experimental models of gastrointestinal cancer. For
example, proglumide, a glutamic acid derivative .sup.[16][66][67]
Benzotript, an N-acyl derivative of tryptophan; L-365,260, a
derivative of Aspercillin .sup.[68], and CI-988 a molecule that
mimics the C-terminal pentapeptide sequence of CCK .sup.[69] have
been shown to effectively neutralize the effects of exogenous
gastrin on gastrointestinal tumor growth both in vitro and in vivo
.sup.[6][70]. However, these antagonists have severe toxic side
effects and lack specificity as they block the action of all
potential ligands of the receptor such as G34 and CCK in normal
cells. Recently, highly potent and selective CCKB/gastrin receptor
antagonists such as YM022 .sup.[71] and YF476 .sup.[72] have been
also described.
[0025] Proglumide and Benzotript have been widely assessed in
pre-clinical studies. The main problem with these compounds is
their lack of potency, with relatively high concentrations required
to displace G17. Despite this, proglumide and benzotript inhibited
the basal and gastrin-stimulated proliferation of a number of cell
lines .sup.[67]. In addition, proglumide increased the survival of
xenograft mice bearing the gastrin-sensitive mouse colon tumor,
MC26 to 39 days in the treated animals from 25 days in the control
animals.
[0026] Due to the low specificity of this class of gastrin
antagonising agents for the gastrin/CCKB receptor, the inhibition
of tumor growth may not be effectively control with gastrin
antagonists. Moreover, the cellular receptors which recognize and
bind the gastrins do not bind all the inhibitors tested .sup.[16].
Thus, if complete inhibition of gastrin binding to the receptor
does not occur in the autocrine growth cascade, then the gastrin
antagonists may be unable to block this mechanism of tumor growth
promotion.
[0027] Recent developments have demonstrated the feasibility of
immunoneutralization of hormones or their receptor moieties in
order to inhibit the hormone controlled physiological functions or
effects, such as cellular growth. (U.S. Pat. Nos. 5,023,077 and
5,468,494)
[0028] For example, immunization with the immunogen G17DT elicits
antibodies that react specifically with the aminoterminal end of
G17 gastrin and Gly-G17 gastrin (U.S. patent application Ser. No.
08/798,423). The antibodies do not cross-react with any of the
other gastrin species tested, including G34 gastrin and CCK.
Antibodies elicited by G17DT inhibit the binding of gastrin to the
CCK-B/gastrin receptor on a variety of gastrointestinal tumor
cells, including pancreatic tumor cells. Antibodies elicited by
G17DT inhibit the growth of human gastric, pancreatic, and
colorectal cancer cells in vitro and in in vivo animal models of
gastric and colorectal cancer. Immunological neutralization has
been discovered to inhibit metastsis of colorectal cancer
.sup.[46][47].
[0029] The alternate or additional immunological weapon against the
gastrin effect on pancreatic cancer growth comprises the induction
of anti-CCKB/gastrin receptor antibody binding with a specific
anti-receptor GRE1 or GRE4 peptide epitope, as described in
co-assigned pending U.S. patent application Ser. No. 09/076,372.
Accordingly, the receptor moieties can be prevented from binding
the circulating gastrin hormone or fragments thereof. Furthermore,
this immunological inhibition of pancreatic cancer advantageously
results in the internalization of the receptor antibody complex
causing apoptosis-like cell death.
[0030] Certain anticancer chemical compounds have been found useful
for treating adenocarcinoma such as pancreatic tumors. For example,
Gemcitabine (2', 2', difluorodeoxycytidine) is a nucleoside analog
with structural similarities to cytarabine. Its mode of action
involves disruption of cell replication. Gemcitabine enters the
cell via a carrier-mediated transport system that is shared with
other nucleosides. It is phosphorylated sequentially to
difluorodeoxycytidine monophosphate (diFdCMP),
difluorodeoxycytidine diphosphate (diFdCDP) and
difluorodeoxycytidine triphosphate (diFdCTP). Preclinical studies
of gemcitabine have shown incorporation of the phosphorylated
diFdCTP into DNA .sup.[73][74].
[0031] Gemcitabine triphosphate is a substrate and competitive
inhibitor of DNA polymerases alpha and epsilon. Once dFdCTP is
incorporated into the growing chain, only one (or perhaps two) more
nucleotide(s) can be incorporated, a novel mechanism termed "masked
chain termination." Once additional residues are incorporated at
the 3' end, gemcitabine cannot be excised by the proofreading
exonucleolytic activity of DNA polymerase .sup.[48]. DNA
fragmentation and apoptosis follow. As predicted by its mode of
action, gemcitabine is active only in S-phase when cells are
actively replicating DNA .sup.[49].
[0032] Since pancreatic cancer has a high occurrence of metastasis,
this method also comprises advantageous combination treatment with
immunological anti-gastrin, anti-CCK-B/gastrin receptor agents and
chemotherapeutic agents such as irinotecan and optionally 5-FU/LV
or gemcitabine, or both.
[0033] Irinotecan is a chemotherapeutic drug (Camposar.RTM.), which
has been approved for some types of cancer, mostly as second-live
treatment. It has been applied in conjunction with 5-FU/LV against
metastatic colorectal carcinoma which progressed after 5-FU
treatment.
[0034] Cisplatin is a drug used in a variety of neoplasms that is
capable of producing inter-and intrastrand DNA cross-links.
Cisplatin can be administered alone or together with other
chamotherapeucics.
[0035] In view of the very poor prognosis of pancreatic cancer and
lack of significant survival afforded by the currently available
therapies, a therapeutic strategy involving immunological targeting
of gastrin and its receptor in combination with chemotherapeutic
methods using one or more chemotherapeutic agents may provide a
novel and efficacious therapy.
SUMMARY OF THE INVENTION
[0036] Contrary to expectations, it has now been discovered that
the immune response to vaccination of the treated animal or human
is not significantly repressed by chemotherapeutics, or at least
can be overcome by adjusting the vaccine dosage.
[0037] Advantageously, therefore, the present invention provides a
treatment of pancreatic cancer comprising combining immunotherapy
with one or more than one anticancer growth active immunogen and
chemotherapy wherein the chemotherapy comprises one or more
chemotherapeutic anticancer agent.
[0038] The invention provides a combination of methods for use in
the treatment of pancreatic cancer including metastatic tumors
thereof, wherein the immunotherapy is administered both in the form
of an active or passive immunological composition comprising one or
more cancer trophic target and the chemotherapy comprise one or
more chemotherapeutic agent suitable for the inhibition of cancer
growth. In the general context of this invention, the active
immunization comprises an anti-growth factor immunogen and/or an
anti-growth factor receptor immunogen, and the passive immunization
comprises anti-growth factor antibodies, and anti-growth factor
receptor antibodies which are polyclonal or monoclonal.
[0039] In particular, the combination of methods provides treatment
of pancreatic cancer by immunological therapy directed against
hormones and receptors thereof which stimulate the growth of
pancreatic cancer cells, and concomitantly by administration of
pharmaceutically acceptable chemotherapeutic agents.
[0040] The invention also provides a combination of treatment of
pancreatic cancer comprising administering an immunogenic
composition containing a conjugate of the amino-terminal G17
peptide epitope covalently linked to an immunogenic carrier
proteins and a chemotherapeutic composition.
[0041] One form of active immunization according to the invention
provides an antigastrin effective immunogenic composition
comprising an epitope of the gastrin peptide G17 which is
covalently linked through a spacer peptide to an immunogenic
carrier or immunogenic carrier fragment.
[0042] More particularly, the invention may provide a conjugate of
the aminoterminal G17 peptide epitope linked to a seven amino acid
peptide spacer, the spacer being attached to an .epsilon.-amino
acid carrying side chain of the lysine residue of diphtheria toxoid
and a chemotherapeutic composition carrier protein.
[0043] The immunogenic composition according to this invention
contains an dosage in units ranging from approximately 10 .mu.g to
5000 .mu.g of immunogen.
[0044] An alternate embodiment of the invention provides an
anti-gastrin receptor immunogen. For example, such an embodiment
provides an immunogen which comprises a CCKB/gastrin receptor
peptide or fragment thereof which elicits antibodies in the
immunized patient, wherein the antibodies are specifically directed
against an epitope of the receptor so as to bind and inactivate the
receptor.
[0045] The antibodies produced by the anti-CCK-B/gastrin receptor
immunogens thereby inhibit the growth stimulatory pathway,
including the autocrine growth-stimulatory pathway of tumor cells
and ultimately the growth of the tumor.
[0046] Another embodiment of the invention provides an immunogen
which elicits an auto-antibody specifically directed to a gastrin
receptor, such that upon binding the antibody is internalized into
the receptor associated pancreatic tumor cell.
[0047] A further embodiment of the invention provides for an
immunogen which elicits an antibody specifically directed to the
gastrin receptor, or fragment thereof, such that upon binding the
antibody is internalized into the nucleus of the receptor
associated pancreatic tumor cell.
[0048] An embodiment of the treatment of pancreatic cancer provides
immunization with an anti-CCKB/gastrin receptor immunogen, alone/or
combined with treatment for the cancer by administering a
composition comprising one, or more than one, chemotherapeutic
agent effective against pancreatic cancer.
[0049] A further embodiment of the invention advantageously
provides an immunogenic composition formulated as a water-in-oil
emulsion amenable for intramuscular injection.
[0050] Another embodiment of the treatment of pancreatic cancer
provides immunization with both anti-gastrin immunogen and
anti-gastrin receptor immunogen combined with one, or more than
one, chemotherapeutic agent.
[0051] The treatment according to the invention combines the
immunological phase of therapy with one or more chemical adjuvant
compounds selected from known pharmaceutically acceptable taxanes,
such as e.g. docetaxel, taxotere, Paclitaxel, 7-Epi-Taxol,
10-Deacetyl Taxol, as well as mixtures thereof, 5-fluorouracil
(5-FU), cisplatin, gemcitabine, irinotecan (also called
Camposar.RTM. or CPT-11), and tamoxifen 5-FU may be administered
with leucovorin.
[0052] The chemotherapy comprises doses of 5-FU ranging from 50 to
1000 mg/m.sup.2/d, with leucovorin at 90 mg/d to 100 mg/d or
irinotecan ranging from 200-300 mg/m.sup.2/d, gemcitabine ranging
from 100-1500 mg/m.sup.2/d; cisplatin (platinol) ranging from 40
mg-100 mg/m.sup.2/d; and tamoxifen from 10 mg-20 mg tablet per day.
For example, combinations of chemotherapeutic agents comprise 5-FU
Cisplatin, 5-FU-Gemcitabine or 5-FU with leucovorin &
cisplatin.
[0053] The invention provides a treatment of G17DT immunogen
(100-500 .mu.g) in combination with gemcitabine of unresectable
metastatic carcinoma of the pancreas in previously untreated
subjects.
[0054] In accordance with this invention, the method of treatment
of pancreatic cancer provides periodic administration of
immunological anti-growth stimulating agents in conjunction with a
chemotherapeutic agent comprising one or more chemical compounds
having an anti-cancer effect. The immunological agents are either
hormone immunogens for active immunization or passive immunization
with exogenous anti-growth factor antibodies. The exogenous human
antibodies can be produced in transgenic animals or other suitable
subjects using standard techniques. For passive immunization, the
antibodies can be monoclonal, polyclonal or a hybrid. The
antibodies are administered in purified form, such as, e.g. IgG
fractions, comprising dosages sufficient to neutralize the
circulating growth factors or hormones, e.g., gastrin G17 or
Gly-G17, or their receptors.
[0055] A further growth factor or hormone specific embodiment of
the invention utilizes the exogenously added anti-CCKB/gastrin
receptor antibody in modified form with agents such as toxins, or
radiolabelled substances. The toxin can be of the cholera type. The
radiolabel can be .sup.125Iodine, .sup.131Iodine, .sup.187Rhenium
or .sup.90Yttrium.
[0056] For example, the embodiment provides a radiolabelled
specific anti-cancertrophic antibody to destroy the cell upon
internalization further in combination with other chemotherapeutic
and other immunologically active agents.
[0057] Radiolabeled antibodies can also be used for detection
diagnoses wherein the radiolabel comprises .sup.125Iodine, .sup.131
Iodine, Technetium (T.sub.c), .sup.111Indium, .sup.67Gallium, or
.sup.90Yttrium.
DETAILED DESCRIPTION OF THE INVENTION
[0058] Anti-G17DT antibodies administered in animals with
xenotransplants of various cancers, as well as antibodies elicited
by active immunization of subjects with colorectal or stomach
cancer with G17DT conjugate, bound both G17 and Gly-G17 gastrins at
high affinity. Furthermore, safety and dose ranging studies in
subjects with advanced colorectal, stomach, and pancreatic cancers
have demonstrated that high-affinity antibodies are elicited by
G17DT immunogen. Biological therapies such as immunization with
G17DT in combination with chemotherapy may show a higher degree of
efficacy than each alone. The higher efficacy is dut to the
inhibition of a proliferative factor such as gastrin, is
cytostatic, and the chemotherapy is a cytotoxic effect. A
combination of the two modalities is synergistic, similarly as
previously demonstrated with anti-HER2 antibody treatment in
combination with chemotherapy in advanced breast cancer .sup.[75]
and which, more specifically, is shown by results of pre-clinical
studies of combinations of G17DT with chemotherapeutic agents.
[0059] The majority of neutralizing antisera raised against gastrin
peptides has been directed against the 5-amino-acid
carboxy-terminal portion of the molecule common to G17 gastrin (SEQ
ID NO: 4), G34 gastrin (SEQ ID NO: 5), and cholecystokinin (CCK).
This carboxy-terminal sequence of these peptide hormones interacts
with the CCK-B/gastrin receptor .sup.[14]. G17DT conjugate was
developed in an attempt to generate antibodies against the
amino-terminal end of G17 and Gly-G17 gastrins. G17DT conjugate is
constructed from a synthetic 16-residue peptide comprising an
epitope derived from the amino acid residue 1-9 of G17 gastrin
linked at the C-terminal to a 7 amino acid residue spacer peptide
terminating in a cysteinyl residue. The peptide is cross-linked via
its C-terminal cysteine residue to a carrier protein, Diphtheria
toxoid (DT), using the bifunctional cross-linker EMCS to form the
G17DT conjugate. G17DT has been formulated in a water-in-oil
emulsion suitable for intramuscular injection.
[0060] Other immunogens for use in the invention are disclosed in
the coassigned U.S. Pat. Nos. 5,023,077, 5,488,494; 5,607,676,
5,866,128; 5,609,870; 5,688,506, and 5,662,702 which are
incorporated herein by reference in their entirety.
[0061] It has been shown that G17-specific antibodies raised, for
example, against the instant G17DT immunogen were affinity-purified
from rabbit serum and tested for their ability to inhibit in vitro
the binding of radioiodinated human G17 to AR42J cells, a rat
pancreatic cancer cell line that expresses gastrin receptors. It
was shown that the anti-G17 antibodies, pre-mixed with the labeled
G17, significantly (>90%) inhibited the binding of G17 to the
cells. This data demonstrate their capacity of the antibodies to
neutralize the biological activity of human G17 in pancreatic
cancer cells.
[0062] G17DT does not cause significant systemic side effects, and
no evidence has been found for deleterious effects of long-term
neutralization of G17 gastrin and Gly-G17 gastrins. The only
significant side effect following immunization with G17DT is
injection site reactions.
[0063] Neutralization of the endocrine and autocrine/paracrine
effects of G17 and glycine-extended G17 gastrin is proposed as a
mechanism by which G17DT immunization can reduce gastrin-stimulated
tumor growth and increase survival of the patient. A G17DT
formulation has been developed that elicits an immune response
while exhibiting an acceptable local reactogenicity.
[0064] Furthermore, as described in the co-assigned international
patent application serial number PCT/US99/10750, anti-gastrin
immunization treatment combined with lower than normal amounts of
Leucovorin/5-FU, has been advantageously effective.
[0065] The methods of the invention are directed to the treatment
of gastrin hormone-dependent tumors in animals, including humans,
and comprise administering to a patient an
anti-CCK-B/gastrin-receptor immunogen, which induces the formation
of antibodies in the immunized patient which bind to the
CCK-B/gastrin-receptor on the tumor cells. Antibodies boudn to the
cell receptors block the binding of the hormone to the receptor and
thereby inhibit the growth promoting effects of the hormone. More
importantly the receptor/anti GRE1 (anti-gastrin receptor epitope
1) antibody complex is rapidly internalized, traverses the
cytoplasm and enters the nucleus. The complex one in the nucleus
triggers the affected tumor cells to commit suicide
(apoptosis).
[0066] The immunogens of the invention comprise natural or
synthetic peptides of the human CCK-B/gastrin-receptor which act as
immunomimics. In particular, two synthetic peptides have been
developed as the immunomimics. These peptides, developed from the
amino acid sequence of the CCK-B/gastrin-receptor, are immunogenic
and cross-reactive with the endogenous CCK-B/gastrin-receptor of
tumor cells both in vivo and in vitro. Peptide 1 consists of amino
acids 5 through 21 of the CCK-B/gastrin-receptor sequence
KLNRSVQGTGPGPGASL (Peptide 1, SEQ ID NO.: 1 in the Sequence
Listing). Peptide 1 constitutes part of the amino-terminal domain
of the receptor and is located on the extracellular surface of the
cell membrane.
[0067] In another embodiment, the immunogen comprises Peptide 4,
which consists of the amino acid sequence of the
CCK-B/gastrin-receptor: GPGAHRALSGAPISF (Peptide 4, SEQ ID NO.: 2
in the Sequence Listing). Peptide 4 is part of the fourth
extracellular domain of the receptor and it too is on the outer
side of the cell membrane.
[0068] The immunogens may also comprise an extension or spacer
peptide suitable for projecting the immunomimic peptide away from
the protein carrier and to enhance its capacity to bind the
lymphocyte receptors. A suitable spacer peptide has the amino acid
sequence SSPPPPC (Serine (Ser) spacer, SEQ ID NO.: 3 in the
Sequence Listing). However, other spacer peptides would be suitable
as well. The immunomimic peptides, with or without the spacer, are
then conjugated to a protein carrier, such as Diphtheria toxoid,
via a cysteine residue at the carboxy terminal end. The spacer
peptides are not immunologically related to the
CCK-B/gastrin-receptor-derived peptides and should therefore
enhance, but not determine, the specific immunogenicity of the
receptor-derived peptides.
[0069] The presence and density of CCK-B/gastrin-receptors on tumor
cells in a patient can be determined in vitro by reacting labeled
anti-receptor antibodies with a sample of obtained from a tumor
biopsy. The anti-receptor antibodies can be labeled with either a
radioactive tracer, a dye, an enzyme or a fluorescent label, as
known in the art. In addition, the responsiveness of the tumor
cells to gastrin can be evaluated in vitro from a tumor biopsy
sample of the patient using standard techniques. Patients having
tumor biopsy samples positive for the CCK-B/gastrin-receptor
antibody assay are typical candidates for treatment by the methods
of the invention.
[0070] An effective dosage ranging from 0.001 to 5 mg of the
immunogenic composition is administered to the patient for the
treatment of the gastrointestinal cancer. The effective dosage of
the immunogenic composition should be capable of eliciting an
immune response in a patient consisting of effective levels of
antibody titer against the CCK-B/gastrin-receptor 1-3 months after
immunization. Following the immunization of a patient, the
effectiveness of the immunogens is monitored by standard clinical
procedures, such as ultrasound and magnetic resonance imaging
(MRI), to detect the presence and size of tumors. The antibody
titer levels against the receptor may also be monitored from a
sample of blood taken from the patient. Booster immunizations are
given as required to maintain an effective antibody titer.
Effective treatment of gastrin-dependent cancers, such as stomach,
liver, pancreatic and colorectal adenocarcinomas, according to this
method should result in inhibition of tumor growth and a decrease
in size of the tumor.
[0071] The antibodies raised by the anti-CCK-B/gastrin-receptor
immunogens of the present invention may have anti-trophic effects
against gastrin-dependent tumors by three potential mechanisms: (i)
inhibition of gastrin binding to its receptor, (ii) degradation or
disruption of the signal transduction pathway of tumor cell
proliferation; and (iii) induction of apoptosis (or cell suicide)
in cells where receptor/antibody complexes are internalized and
migrate into the nucleus.
[0072] In another embodiment of the invention,
anti-CCK-B/gastrin-receptor antibodies are administered to a
patient possessing a CCK-B/gastrin-receptor-responsive tumor. The
antibodies specifically bind to the CCK-B/gastrin-receptors on the
tumor cells. The binding of the antibodies to the receptors
prevents the binding of gastrin to its ligand in the membranes of
cells and, therefore, the growth signal for the gastrin-dependent
tumor cells is inhibited and the growth of the tumor is arrested.
The antibodies are preferably chimeric or humanized antibodies, or
fragments thereof, which effectively bind to the target receptor
and may be produced by standard techniques, such as, e.g., those
disclosed in U.S. Pat. Nos. 5,023,077, 5,468,494, 5,607,676,
5,609,870, 5,688,506 and 5,662,702. These exogenously produced
antibodies may also be useful for killing tumor cells that bear the
CCK-B/gastrin-receptor on their plasma membranes by virtue of their
inhibiting the growth of the tumor cells or delivering a toxic
substance to the tumor cell. Therapeutic anti-CCK-B/gastrin
antibodies are those reactive with extracellular domains 1 and 4 of
the receptor protein as GRE-1 and GRE-4, respectively. The
inhibition of tumor growth in this method of immunization is also
monitored by ultrasound imaging and MRI and repeated immunizations
are administered as required by the patient.
[0073] The effectiveness of the antibodies in inhibiting tumor cell
growth and killing of tumor cells can be enhanced by conjugating
cytotoxic molecules to the anti-CCK-B/gastrin antibodies and the
anti-gastrin G17 or G17-gly antibodies. The cytotoxic molecules are
toxins, for example, cholera toxin, ricin, .alpha.-amanitin, or
radioactive molecules labeled, for example, with .sup.125I or
.sup.131I, or chemotherapeutic agents, as for example, cytosine
arabinoside or 5-fluorouridine (5-FU).
[0074] In addition to antibodies radiolabeled with .sup.125I and
.sup.131I, the anti-CCK-B/Gastrin-receptor antibodies can also be
labeled with radionuclides such as .sup.111Indium and
.sup.90Yttrium. In this aspect of the invention, the antibodies are
useful for the detection and diagnosing of CCK-B/gastrin-receptor
possessing tumors in vivo, by administering these antibodies to the
patient, and detecting bound antibodies on
CCK-B/gastrin-receptor-containing tumor cells. After allowing the
radio labeled anti-CCK-B/gastrin antibodies to reach the tumor,
about 1-2 hours after injection, the radioactive, "hot spots" are
imaged using standard scintigraphic procedures as previously
disclosed (Harrison's Principles of Internal Medicine, Isselbacher
et al. eds. 13.sup.th Ed. 1994).
[0075] The compositions in which the immunogens are administered
for the treatment of gastrin-dependent tumors in patients may be in
a variety of forms. These include, for example, solid, semi-solid
and liquid dosage forms, such as tablets, powders, liquid
solutions, suspensions, suppositories, and injectable and infusible
solutions. The preferred form depends on the intended mode of
administration and therapeutic applications. The compositions
comprise the present immunogens and suitable pharmaceutically
acceptable components, and may include other medicinal agents,
carriers, adjuvants, excipients, etc. Suitable adjuvants may
include normuramyl dipeptide (nor-MDP, Peninsula Labs., Calif.),
and oils such as Montanide ISA 703 (Seppic, Inc., Paris, France),
which can be mixed using standard procedures. Preferably, the
compositions are in the form of a unit dose. The amount of active
compound administered for immunization or as a medicament at one
time, or over a period of time, will depend on the subject being
treated, the manner and form of administration, and the judgment of
the treating physician.
[0076] The anti-CCK-B/gastrin-receptor antibodies of the invention
for passive immunization can be administered to a patient
intravenously using a pharmaceutically acceptable carrier, such as
a saline solution, for example, phosphate-buffered saline.
[0077] The pharmacology and toxicology for the instant combined
treatment of advanced pancreatic cancer is described below:
EXAMPLE A
[0078] G17DT was administered to 28 patients with advanced
pancreatic adenocarcinoma at weeks 0,1 and 3 at a 250 .mu.g dose
[16]. Only one patient failed to mount an antibody response. G17DT
was well tolerated with no systemic side effects. One patient
developed a sterile abscess that settled following aspiration.
Survival was found to be significantly improved in G17DT patients
when compared to an historical control matched in terms of age,
stage and co-existing morbidity by POSSUM scoring .sup.[40].
[0079] Concerning the response rates of subjects with pancreatic
cancer the median time to onset of the immune response to G17DT
appears to be dose related and to be optimal at.gtoreq.250 .mu.g
G17DT.
EXAMPLE B
[0080] The immuno-electronmicroscopy studies used an antiserum
directed against the amino-terminal end of the
CCK-B/gastrin-receptor (GRE-1 epitope) show that after one hour
incubation, the distribution of immunogold-label
CCK-B/gastrin-receptor antibody was quickly internalized as 12% of
the antibody receptor complex was associated with the cell
membrane, 36.6% within the cytoplasm, 7.9% in the nuclear membrane
and, quite surprisingly, 43.5% within the cell nucleus. Areas of
intense CCK-B/gastrin-receptor immunoreactivity within the nucleus
were found on chromatin, which may suggest specific binding sites
for regulation of the DNA.
[0081] These electron microscopy studies with anti-immunoglobulin
conjugated to gold beads (immmunogold) reveal that an extremely
rapid turnover of the anti-receptor/receptor complex occurs in the
tumor cells; as early as 10 seconds after exposure to antibodies,
complexes are detectable in the cell nucleus.
EXAMPLE C
Immunological Efficacy
[0082] Patients' sera were assessed for antibodies to G17 gastrin
at 2-4 weekly intervals. Anti-gastrin-17 antibodies were measured
using a titration and inhibition radioimmunoassay with .sup.125I
labeled human gastrin-17. Assays for antibodies to G17 gastrin in
the pancreatic cancer trials 1 and 2 have been performed by a G17
antigen-based ELISA.
[0083] The pharmacodynamics of the immune response to G17DT was
evaluated as a function of the dose and treatment regimen for
G17DT. The frequency of seroconversion and time to onset of
production of G17 gastrin-specific antibodies was used to estimate
the optimal dose.
[0084] A positive immune response in test serum by RIA was defined
as being.gtoreq.40 fold above non-specific background determined on
a 1:40 dilution of pre-immune subject serum within the first 12
weeks post-immunization. This corresponds to approximately 10% of
total .sup.125I G17 cpm added in the RIA assay. A positive response
in the ELISA assay approximates.gtoreq.4 units in the ELISA assay
which is comparable to that observed by RIA.
[0085] To facilitate comparison of doses and formulations, the
immune response up to and including the 12-week time point observed
in subjects with non-resectable, locally advanced (stage II/III)
and metastatic (stage IV) pancreatic cancer were used to determine
the proportion of immune responders among the treatment groups in
the various studies. The proportion of immune responders and the
median time to develop an immune response are summarized in Tables
A and B, respectively.
[0086] A dose finding phase II study of G17DT in 22 patients with
pancreatic carcinoma demonstrated greater survival in patients who
mounted an adequate antibody response when compared to
non-responders (7.89 versus 4.93 months) .sup.[39].
1TABLE A Immune response in subjects with Stage II-IV pancreatic
cancer Studies 1 & 2 Study (Stage II-IV) G17DT Dose Schedule n
N.sup.a,b % 10 .mu.g 0, 4, 8 wk -- -- -- 10 .mu.g 0, 2, 6 wk -- --
-- 100 .mu.g 0, 4, 8 wk -- -- -- 100 .mu.g 0, 2, 6 wk 5 13 38 165
.mu.g 0, 4, 8 wk -- -- -- 250 .mu.g 0, 4, 8 wk -- -- -- 250 .mu.g
0, 2, 6 wk 6 10 60 250 .mu.g 0, 1, 3 wk -- -- -- 330 .mu.g 0, 4, 8
wk -- -- -- 330 .mu.g 0, 2, 6 wk -- -- -- 330 .mu.g 0, 2, 10 wk --
-- -- 495 .mu.g 0, 4, 8 wk -- -- -- 990 .mu.g 0, 4, 8 wk -- -- --
Total 11 23 48 n = number of subjects with an immune response. N =
number of subjects (immune responders and non-responders) that have
completed 12 weeks % = (n/N) .times. 100 .sup.aIn study 1, 4
subjects have not completed 12 weeks (evaluation ongoing). .sup.dIn
study 2, 11 subjects have not completed 12 weeks (evaluation
ongoing); no immune response data available.
[0087]
2TABLE B Time to immune response in subjects with Stage II-IV
pancreatic cancer 1.sup.a & 2.sup.b Study (Stage II-IV) G17DT
Dose Schedule Median (weeks) .+-. SD 10 .mu.g 0, 4, 8 wk -- 10
.mu.g 0, 2, 6 wk -- 100 .mu.g 0, 4, 8 wk -- 100 .mu.g 0, 2, 6 wk 10
.+-. 1 165 .mu.g 0, 4, 8 wk -- 250 .mu.g 0, 4, 8 wk -- 250 .mu.g 0,
2, 6 wk 6 .+-. 3 250 .mu.g 0, 1, 3 wk -- 330 .mu.g 0, 4, 8 wk --
330 .mu.g 0, 2, 6 wk -- 330 .mu.g 0, 2, 10 wk -- 495 .mu.g 0, 4, 8
wk -- 500 .mu.g 0, 4, 8 wk -- 990 .mu.g 0, 4, 8 wk -- Mean -- 8
.+-. 2 .sup.aIn study 1, 4 subjects have not completed 12 weeks
(evaluation ongoing). .sup.bIn study 2, 11 subjects have not
completed 12 weeks (evaluation ongoing); no immune response data
available.
[0088] Chemotherapy
EXAMPLE 1
Activity of Gemcitabine
[0089] The US FDA approved gemcitabine for use in pancreatic cancer
based on the results from several clinical trials [Gemzar.RTM.
(gemcitabine HCl) package insert, 1996, 1998, summarized in Table
3]. Subjects with locally advanced or metastatic disease were
treated with gemcitabine 1000 mg/m.sup.2 weekly.times.7, or
.times.3, followed by one week of rest, then weekly.times.3 every
four weeks thereafter. Early Phase II trials indicated that a
significant number of subjects experienced some palliation of
symptoms despite only modest objective response rates. To
quantitate these effects, a novel end point termed Clinical Benefit
Response was developed for use in subsequent trials.
[0090] Clinical Benefit Response is a composite of degrees of pain
(analgesic consumption and pain intensity), Karnofsky performance
status, and weight change. Gemcitabine was the first agent to be
approved using clinical benefit response as an endpoint. Clinical
benefit required a sustained (.gtoreq.4 weeks) improvement in at
least one parameter without worsening in any others. Subjects were
considered clinical benefit responders only if they showed at least
a 50% reduction in the level of pain (Memorial Pain Assessment
Card) or consumption of pain medication, or at least a 20-point
improvement in performance status (Karnofsky Performance Scale) for
a period of at least four consecutive weeks, without showing any
sustained worsening in any of the other parameters. A subject was
also considered a clinical benefit positive responder if stable in
all these parameters.
EXAMPLE 2
Therapy with Gemcitabine
[0091] Prior to the approval of gemcitabine (Gemzar.RTM., Eli Lilly
& Co.) in 1996 for the first-line treatment of locally advanced
and metastatic adenocarcinoma of the pancreas, 5-fluorouracil
(5-FU) had been the standard of GI or pancreatic cancer care for 30
years. A review .sup.[50] of 28 Phase II trials involving 25 new
agents showed that none provided any improvement over 5-FU in
subject outcome, with a median objective response rate of 0% (range
0-14%) and a median survival of 3 months (range 2-8.3 months).
Suggestions that combined chemotherapeutic treatments offered
improvements over 5-FU alone were not confirmed in randomized Phase
III trials .sup.[50].
[0092] Gemcitabine exhibits several self-potentiation mechanisms
which enhance its incorporation into DNA .sup.[76]. These effects
are mediated via interactions of gemcitabine and its metabolites
with the enzymes of pyrimidine nucleotide metabolism and are
believed to be significant in producing the high concentration of
active drug in cells and in prolonging the half-life of active drug
in cells. These include the following:
[0093] Gemcitabine triphosphate directly inhibits dCMP deaminase,
thus inhibiting the breakdown of gemcitabine monophosphate to
difluorodeoxyuridine monophosphate (the major breakdown
pathway)
[0094] Gemcitabine triphosphate may also inhibit CTP synthase,
which catalyzes the synthesis of CTP from UTP and ammonia (or
glutamate), additionally depleting dCTP pools.
[0095] Inhibition of ribonucleotide reductase by gemcitabine
diphosphate reduces the concentrations of dCTP and dCDP, both of
which feedback inhibit deoxycytidine kinase. Thus, more gemcitabine
is phosphorylated because the feedback inhibition is removed.
[0096] Gemcitabine has also been shown to be a potent
radiosensitizer. This activity does not parallel the incorporation
of the phosphorylated drug into DNA. Rather, it paralleles the
intracellular depletion of dATP, suggesting that the inhibition of
ribonucleotide reductase is the key mechanism of this action
.sup.[73][74][1]. In general, agents (e.g. urea) that reduce dNTP
pools act as radiation sensitizers. The intermediate diFdCDP
(gemcitabine diphosphate) is a potent inhibitor of ribonucleotide
reductase. This inhibition causes a decrease in all four
deoxynucleotide triphosphate intracellular pools, which results in
an inhibition of DNA synthesis. Variation in the extent of
depletion of each dNTP pool in different cell types suggests that
the greater depletion of the dATP pool in particular observed in
solid tumor cell types may account for the greater clinical
activity of gemcitabine in solid tumors .sup.[74][1].
[0097] Gemcitabine rapidly distributes into total body water after
IV administration. The volume of distribution is affected by
duration of infusion, age, and sex. Longer infusions result in
higher concentrations.
[0098] Clearance is independent of dose and duration of infusion
but is variable, and is influenced by age. Because the volume of
distribution increases with longer infusion times, its elimination
half-life is longer when it is infused over a longer period.
[0099] Gemcitabine is deaminated by cytidine deaminase in plasma to
diflurodeoxyuridine, which is inactive. Only 5% is excreted
unchanged as gemcitabine.
[0100] Gemcitabine is generally less well tolerated than 5-FU, but
despite a higher incidence of adverse events, its overall toxicity
is considered moderate. There is no evidence of cumulative
toxicity.
[0101] A treatment of the invention combines immunoneutralization
of G17 gastrin or G17-Gly gastrin with the chemotherapy with
gemcitabine. The advantageous aspect of this combination affords a
lower dosage of gemcitabine or irinotecan (or some similarly
amenable and approved anti-cancer drug) such that the toxicity and
other adverse side effects are reduced. In addition, the
immunization with, e.g., G17-DT immunogen containing compositions,
can be administered at a time preceding the chemotherapy in order
to avoid suppressing of the immuno response before a sufficient
titer of auto-antisera has been raised in the treated subject.
EXAMPLE 3
Therapy with Irinotecan
[0102] Irinotecan injection (irinotecan hydrochloride injection) is
a semisynthetic derivative of camptothecin, an alkaloid extract
from plants such as Camptotheca acuminata. The chemical name is
(S)-4,1-diethyl-3,4,12,14-tetrahydro-4-hydroxy-3,14-dioxi-[H-pyrano[3',4'-
:67]-indolizino[1,2-b]quinolin-9-yl-[1,4'-bipiperidine]-1'-carboxylate,
monohydrochloride, trihydrate. It is supplied as a sterile, pale
yellow, clear, aqueous solution. Each milliliter of solution
contains 20 mg irinotecan. (The Camptosar package insert provides
detailed labeling information for irinotecan). Irinotecan is an
emetogenic. Therefore patients may receive premedication with
antiemetic agents. Irinotecan therapy had been shown to cause GI
adverse effects, in particular early and late diarrhea. Early
diarrhea may be accompanied by cholinergic symptoms. Prophylactic
or therapeutic administration of atropine should be considered in
patients experiencing cholinergic symptoms. Late diarrhea should be
promptly treated with loperamide. In addition to the GI
manifestations, irinotecan has been shown to cause myelosuppresion
and hypersensitivity reactions. Only patients with adequate
hematologic, renal, and hepatic function, as well as patients with
no contraindication to irinotecan from previous irinotecan-based
therapy, are able to avoid or immunize the frequency and severity
of toxic effects such as neutropenia and GI abnormalities.
[0103] Patients are permitted to remain on the medications they are
taking except for immunosuppressants, including systemic (i.e.,
oral or injected) corticosteroids. All concomitant medications
should be recorded on the appropriate page of the CRF.
[0104] Palliative radiotherapy is allowed. In the event that
gemcitabine therapy is terminated because of a SAE, G17DT
immunization can be continued.
EXAMPLE b 4
Therapy with Cisplatin
[0105] Injections with Platinol, a solution of cisplatin or
cis-diammine dichloroplatinual II, is used mostly in combination
with other cytotoxic agents has used as a potential cure of
testicular germ cell neoplasms. Substantial activity has been
observed in the treatment of small cell lung cancer, bladder cancer
and ovarian germ cell tumors. According to the invention, cisplatin
may augment antipancreatic cancer treatment in combination with
other pharmaceutically acceptable cytitoxic agents and immunogens
or exogenous application of anti-cancertroph antibodies. Suitable
effective dosing may range as high as 1000 mg/m.sup.2 per week
although the chemotherapeutic effect may be enhanced with
simultaneous immunotherapy so as to allow lower chemotherapeutic
dosages.
EXAMPLE 5
Effect of Gemcitabine on G17DT Immunogenicity
[0106] The example depicts an in vivo test to assess the effect of
the chemotherapeutic agent Gemcitabine on the immunogenicity of the
G17DT immunogen. For that purpose, as a model animal system, mice
were immunized intraperitoncally (IP) with 125, 250 and 500 .mu.g
doses of G17DT in Montanide ISA 703 emulsions of 0.1 ml volume on
days 0, 28 and 56. Gemcitabine was given intravenously (IV) at a
dose of 21.4 mg/kg in a volume of 0.2 ml on days 0, 7, 14, 21, 28,
35, 42, 56, 63 and 70. Control mice received saline vehicle without
the chemotherapeutics. The resultant anti-G17 antibody responses
were measured by ELISA in sera collected every two weeks, and one
bleed at day 21, over the course of the study.
[0107] The G17DT immunogen was formulated under sterile conditions
using PBS (physiological saline solution) as diluent. The emulsion
was produced by mixing the aqueous phases of immunogens with
Montanide ISA 703 at an oil: aqueous phase w/w ratio of 70:30.
[0108] Aliquots 8-10 mg dry Gemcitabine were weighed to be
solubilized in PBS at a human treatment concentration of 3.424
mg/ml Gemcitabine before i.v. administration.
[0109] The results of the treatment over the course of 84 days
showed that all mice responded to G17DT immunogen with similar
kinetics comparing the median responses of all groups. (see Table
1).
[0110] Mice immunized with 125 .mu.g G17DT manifested a statistical
decrease in mean anti-G17 titers when concomitantly treated with
Gemcitabine. However, the suppression was overcome by increasing
the dose of immunogen to 250 .mu.g or 500 .mu.g G17DT.
[0111] This second part of the example depicts cell proliferation
of human pancreatic cell lines, PANC-1, BxPC3 and PAN-1 using a
tetrazolium-based combined with anti-gastrin G17 antibodies induced
by G17DT (10-500 .mu.g/ml). The G17DT elicited antibodies are
active against both serum-associated and tumor-secreted,
proliferative forms of gastrin. The PAN-1 cell were administered at
clinically reflective doses.
[0112] G17DT concentrations of 100 and 50 .mu.g/ml increased the in
vitro inhibitory effects of Gemcitabine (1.0-0.01 .mu.g/ml) by
11-38% (p<0.05, ANOVA) when compared to the individual agents
for all three cell lines.
[0113] In vivo G17DT alone inhibited basal pancreatic tumor weight
by 33% (p=0.016, ANOVA) compared to 38% for Gemcitabine (p=0.004,
ANOVA). When combined the agents inhibited tumor weight by 55%
which was significant from G17DT alone (p=0.025). Thus the
immunological agent G17DT may promote the therapeutic efficacy of
Gemcitabine.
3TABLE 1 Mean Anti-G17 Titer .+-. Standard Error Plus Student's
t-Test DAY OF STUDY 0 14 21 28 42 56 70 84 Group 1; 125 .mu.g G17DT
0 1.006 .+-. 1.132 .+-. 1.227 .+-. 74.780 .+-. 40.200 .+-. 241.140
.+-. 95.940 .+-. Placebo Treatment 240 140 210 7.655 4.883 37.905
23.248 Group 2, 125 .mu.g G17DT 0 292 .+-. 408 .+-. 408 .+-. 43.860
.+-. 21.497 .+-. 64.200 .+-. 37.774 .+-. Gemcitabine Treatment 59
77 104 11.118 6.813 18.788 9.480 t-test Group 1 vs. 2 0.020.sup.1
0.002.sup.1 0.008.sup.1 0.051.sup.1 0.054.sup.1 0.003.sup.1
0.049.sup.1 P(T <= t) two-tail Group 3; 250 .mu.g G17DT. 0 2.047
.+-. 2.074 .+-. 2.349 .+-. 86.840 .+-. 25.913 .+-. 71.788 .+-.
42.166 .+-. Placebo Treatment 717 575 622 34.076 8.730 21.755
13.013 Group 4; 250 .mu.g G17DT. 0 923 .+-. 1.899 .+-. 2.863 .+-.
169.300 .+-. 40.620 .+-. 256.560 .+-. 73.220 .+-. Placebo Treatment
242 724 1.284 65.955 11.494 59.743 17.674 t-test Group 3 vs. 4
0.176 0.855 0.728 0.299 0.338 0.020.sup.1 0.195 P(T <= t)
two-tail Group 5; 500 .mu.g G17DT. 0 1.555 .+-. 4.703 .+-. 6.489
.+-. 107.398 .+-. 43.146 .+-. 196.000 .+-. 118.667 .+-. Placebo
Treatment 160 963 1.545 26.096 13.699 44.006 50.824 Group 6; 500
.mu.g G17DT. 0 1.100 .+-. 1.715 .+-. 4.372 .+-. 653.925 .+-.
162.900 .+-. 166.800 .+-. 77.450 .+-. Placebo Treatment 452 790
2.127 360.669 90.679 87.853 13.846 t-test Group 5 vs. 6 0.370
0.043.sup.1 0.436 0.130 0.184 0.760 0.407 P(T <= t) two-tail
.sup.1Statistical significance at p .ltoreq. 0.05
[0114] Another embodiment of the present invention provides
treatment with more than one chemotherapeutic agent in combination
with active immunization against an appropriate growth factor
and/or growth factor receptor. For example, such treatment can
involve a combination of 5-FU/Leucovorin or 5-FU plus
cisplatinum.
[0115] As a preclinical experiment, mice were treated with a
combination of the two anticancer agents 5-FU and Cisplatinum and
tested as to the extent of numerous suppressive effects.
EXAMPLE 6
Effect of 5-FU & Cisplatinum on G17DT Immunogenicity
[0116] This example concerns the effect of co-treatment with the
chemotherapeutic agent 5-fluorouracil (5-FU) and Cisplatinum
(II)--Diamine Dichloride (Cisplatinum as the active ingredient of
the drug formulation cisplatin) upon the immunogenicity of G17DT
immunogen in mice.
[0117] G17DT immunogen was formulated with Montanide.RTM. ISA 703
at 1.25 mg/ml of G17DT conjugate. Mice were immunized
intraperitoncally (IP) with an injection volume of 0.1 ml
delivering a dose of 125 .mu.g G17DT on days 0, 28 and 56. The
chemotherapeutic dosing regimen was based on the doses recommended
for human patients. Thus the combined 5-FU plus Cisplatinum was
administered to the test group on day 0, following by 5-FU above on
days 1 and 2 by intravenous injection in 0.2 ml volume at doses of
10.0 mg/kg 5-FU and 1.0 mg/kg Cisplatinum. Control mice were
immunized while receiving saline vehicle without the
chemotherapeutics. As supportive therapy for the potential
dehydration caused by Cisplatinum, all mice received IP 1.0 ml PSS
(Physiological Saline solution). The anti-G17 antibody levels in
sera collected at 14-day intervals (plus an additional on d 21)
were assayed by ELISA.
[0118] The G17 DT immunogen was formulated as described in Example
4. The 5FU and Cisplatinum formulations were prepared at 10.0 mg/kg
for 5-FU and 1.0 mg/kg for Cisplatinum to provide calculated doses
of 320 mg of 5-FU and 32 mg of Cisplatinum. The dry aliquots of
5-FU and Cisplatinum were reconstituted on treatment days by
dissolution in the same PSS to yield 1.6 mg/ml and 0.16 mg/ml,
respectively. For day 1 and 2, 5-FU alone was given at 1.6 mg/ml in
PSS.
[0119] The subject mice were ten CAF1 female, about 18 months old.
All mice were G17-immunized at a dose (IP) of 0.1 ml of G17 DT on
days 0, 28, 56 of study. All chemotherapeutics were administered in
volumes of 0.2 ml. Control mice received 0.2 ml of PSS placebo,
according to the treatment regimen. To counter Cisplatinum related
dehydration, all mice were injected IP with 10 ml PSS per mouse.
The mice were bled every 14 days starting on day 0 and ending on
day 84. The sera were assayed by ELISA, showing that all mice
responded to G17 DT immunogen with significant titers of anti-G17
antibodies. The responses of both groups peaked on day 70. The
mean/median response of the combination treatment group was
overcome by the administration of the second injection of
immunogen. The results indicate that the 5FU plus Cisplatinum
treatment (following a dose regimen designed for humans) had no
statistically significant negative effect on the anti-G17 antibody
response.
4TABLE 2 A Comparison of Anti-G17 Antibody Mean Titers by ELISA
(Ex. 6) (plus/minus S.D.) DAY OF STUDY 0 14 21 28 42 56 70 84 Group
1, 125 .mu.g 100 997 .+-. 1,099 .+-. 1,029 .+-. 70,660 .+-. 48,020
.+-. 108300 .+-. 50500 .+-. 194 249 355 30571 22382 44771 11449
Group 2, 125 .mu.g 100 874 .+-. 739 .+-. 266 .+-. 81,400 .+-.
35,966 .+-. 15,4360 .+-. 48,860 .+-. G17DT, 5-FU- 222 265 83 34429
14014 41771 10797 CISPLATINUM Treatment t-test Group 1 vs. 2 0.687
0.351 0.066 0.821 0.660 0.473 0 920 P(T <= t) two-tail
EXAMPLE 7
A. Combined Treatment with Immunization and Gemcitabine
(Protocol)
[0120] The following clinical treatment regime is provided:
5 MEDICATION G17DT Gemcitabine (immunotherapy + Days 1, 28, 56 Day
1 and continue once a chemotherapy) week for a total of 7 weeks,
followed by 1 week rest. Then continue with 4-week cycles of 3
weekly admini- strations followed by 1 week rest each cycle.
Sampling Schedules: Blood Chemistry: weekly Hematology: weekly
Urinalysis: weekly Immunology: bi-weekly to week 12, monthly after
week 12 Diagnostics prior to entry: Endoscopy: pre-enrollment CT
scan and Chest x-ray: pre-enrollment Diagnostics follow up: CT
scan: monthly Chest x-ray: as needed
[0121] The treatment(s) can be administered up to disease
progression, unacceptable toxicities or withdrawal of consent. If
the unacceptable toxicities are due to chemotherapy and the
subject's disease has not progressed, chemotherapy can be stopped
and immunotherapy can be continued as planned. Immunotherapy is
continued after the onset of disease progression and is stopped
only for unacceptable toxicity attributable to G17DT or withdrawal
of consent.
[0122] Gemcitabine
6 Dose: 1000 mg/m.sup.2 Route: in 250 ml of 0.9% sodium chloride
over 30 min., IV infusion Schedule: Day 1 and continue once a week
for a total of 7 weeks, followed by 1 week rest.
[0123] Then continue with 4-week cycles of 3 weekly
administrations, followed by 1 week rest each cycle.
[0124] Alternatively, the dosage of gemcitabine may be reduced to
about 750 mg/m.sup.2 or 500 mg/m.sup.2 or less.
B. Combination with Irinotecan
[0125] Irinotecan was initially approved as second-line therapy for
patients with metastatic colorectal carcinoma whose disease has
recurred or progressed following 5-FU-based therapy. Subsequently,
irinotecan in combination with 5-FU and LV was approved as
first-line therapy for treatment of this disease. Irinotecan-based
therapy, however, is not without significant morbidity, including
diarrhea and myelosuppression. To reduce these side effects, dose
adjustments are often necessary that may reduce the efficacy of
irinotecan. Patients who fail irinotecan-based therapy, thereby,
are left with few options for the efficacious treatment of their
disease.
[0126] Immunotherapy combined with irinotecan has the potential to
enhance overall therapeutic effect, while reducing side effects
associated with irinotecan treatment. In addition to having
antitumor activity on its own, gastrin neutralization by G17DT
administered prior to 5-FU and LV treatment has been shown to
enhance the antitumor activity of 5-FU and LV therapy, and
potentiated the activity of suboptimal doses of 5-FU on rat
colorectal tumors.
[0127] Using this rationale, it can be proposed that G17DT may also
potentiate the efficacy of irinotecan and offer a potentially new
treatment modality that combines the cytostatic action of
antigastrin immunization with the cytotoxic effects of
chemotherapy. In addition, immunization with G17DT could be used
with drugs whose maximum doses must be reduced due to associated
serious AEs.
[0128] G17DT is administered as an intramuscular injection of 250
.mu.g in 0.2 mL vehicle. To elicit an immune response, G17DT is
administered in the initial treatment period at Week 1. In the
absence of Grade 2 or greater allergic reaction to G17DT following
first injection of G17DT, additional doses of G17DT are
administered at Weeks 5, 9; thereafter G17DT is administered
following a decrease in anti-G17 titer of 50% or more from the
maximum titer.
[0129] Irinotecan is administered as an intravenous infusion of 125
mg/m.sup.2 over 90 minutes starting at Week 5 or 4 weeks after the
initial administration of G17DT. Each cycle of treatment consists
of irinotecan i.v. administration by infusion once weekly for 4
weeks, followed by a 2-week rest period. Additional cycles of
treatment are repeated until disease progression, dose limiting
toxicity (DLT), or patient withdrawal. If necessary, doses of
irinotecan can be adjusted by using specific dose modification
rules to accommodate individual patient tolerance of treatment. In
the absence of DLT or progressive disease, patients continue the
G17DT-irinotecan combination treatment regimen. This dosing regimen
is based on results from 3 open-label, single-agent clinical
studies involving a total of 304 patients.
Example 7
Tumor Response Criteria
[0130] Abdominal/pelvic CT scan with IV contrast and chest x-ray
(as needed) can be used to assess tumor burden.
[0131] Examples of such lesions evaluated by clinical examination
or imaging tools include:
[0132] a skin nodule or superficial lymph node minimum.gtoreq.10
mm.times..gtoreq.10 mm
[0133] a liver lesion, soft tissue, lymph node and masses
investigated by CT scan (minimum.gtoreq.20 mm.times..gtoreq.10
mm).
[0134] These include all the lesions that can be measured with only
one diameter.gtoreq.20 mm on CT scan or.gtoreq.10 mm on physical
examination.
[0135] An example of these lesions is a palpable abdominal mass or
soft tissue mass that can be measured only in one diameter.
EXAMPLE 8
Evaluation of Response
[0136] Subjects must have received 3 immunizations with G17DT
and/or GRE1DT and a minimum of one 7-week cycle or two 4-week
cycles of treatment with gemcitabine with at least one follow-up
tumor assessment using the same method as baseline to be considered
evaluable for response unless "early progression" occurs, in which
case they are considered evaluable (in progressive disease).
Subjects on therapy for at least this period have their response
classified according to the definitions set out below.
[0137] Immune response assessments is made by ELISA on blood
samples collected from subjects every 2 weeks up to 12 weeks and
every 4 weeks thereafter. Tumor assessment for all lesions must be
performed every 4 weeks on therapy until the documentation of the
progression. Tumor response should be reported on follow-up visits
every 4 weeks for the subject who goes off study for reason other
than progressive disease (PD).
[0138] No further anti-tumor therapy is given after end of
treatment until disease progression is documented, except if the
subject requests further therapy or the investigator deems it
necessary. All uni- or bi-dimensionally measurable lesions should
be measured every subsequent 4 weeks. Additional assessments should
be performed to confirm a response at least 28 days after the first
response has been observed. In addition, extra assessments may be
performed if there is a clinical suspicion of progression. When
multiple lesions are present, this may not be possible and, under
such circumstances, up to 6 measurable target lesions which are
representative of all organs involved should be selected for the
involved sites, giving the priority to bi-dimensionally measurable
lesions, then uni-dimensionally measurable lesions.
[0139] Best overall response is the best response designation
recorded from the start of treatment until disease progression.
[0140] Complete and partial responses have to be confirmed by two
evaluations of the disease, taken at least 4 weeks apart (see above
for assessment time).
[0141] No change is only accepted if it is measured at least 4
weeks after the treatment start.
[0142] Tumor response, time to progression, time to treatment
failure and survival can be analyzed both on an intent-to-treat
basis and on the evaluable population.
[0143] The period for complete response lasts from the date the
complete response was achieved to the date thereafter on which
progressive disease is first noted. In those subjects who achieved
partial response, only the period of overall response should be
recorded. The period of overall response lasts from the day of the
first observation of response (partial or complete) to the date of
first observation of progressive disease.
[0144] Time to disease progression is the time measured from the
start of treatment to the first progression, death, or
discontinuation of both chemotherapy and immunotherapy, whichever
occurs first. Subjects that have not progressed at the time of the
final analysis can be censored at the date of their last tumor
assessment. Subjects who receive non-study anti-tumor therapy
before disease progression can be censored at the date of the last
assessment before therapy.
[0145] Time to treatment failure is the time measured from the
start of treatment to the date of failure (progression, relapse,
death or any other cause of treatment discontinuation).
[0146] Survival is measured from the start of treatment to the date
of death from whatever cause. Subjects alive as of the final
analysis will be censored at their last contact date.
[0147] The pharmacodynamics of the immune response following the
primary series of three injections are assessed by the proportion
of immune responders with.gtoreq.4 ELISA units sustained for 2
consecutive bleeds in study Arm A attained by week 12 following the
first immunization and by the mean and median peak titers.
Immunoassays are performed by G17 antigen-based ELISA. The quality
of the antibody response is measured by inhibition RIA and assessed
by dissociation constant (Kd) and antigen binding capacity (ABC),
and ABC/Kd ratio.
[0148] The mean and median duration of the immune response from
peak titer to<25% of peak titer is assayed in order to determine
the time to administer a booster immunization.
[0149] Taxanes
[0150] Recent treatments of advance prostate cancer include the
administration of chemotherapeutic agents such as taxanes. Taxanes,
such as, for example, docetaxel, are effective microtubule
inhibitors thereby interfering in the further transition of the
cell cycle at G2/M check-point. Taxanes have now emerged as a
promising class of newly approved chemotherapies currently under
investigation in hormone-refractory prostate cancer. A number of
recent studies indicate that the taxane, i.e. docetaxel, is
particularly active. For example, 35 patients with
hormone-refractory prostate cancer were treated with docetaxel at
75 mg/m.sup.2 every 21 days while being maintained on androgen
suppression. Toxicity remained tolerable throughout the treatment;
although there were two deaths during the study, one due to lung
toxicity/pneumonia and one due to pulmonary embolus. Responses,
defined as a more than 40% PSA decline and a more than 50%
reduction of bi-dimensional cross-products in patients with
measurable disease, were seen in 17 of the 35 patients enrolled,
including one complete response. Responses were maintained for a
median of nine months (range, 2 to 24 months). The median overall
survival in this study was 27 months. Preclinical studies suggested
a potential benefit for the combination of docetaxel with
estramustine in the treatment of patients with hormone-refractory
prostate cancer. Based on data from two phase I studies, the
docetaxel dose applied for phase II study which was undertaken in
combination with estramustine in human subjects was 70 mg/m.sup.2
or 60 mg/m.sup.2. Phase II studies of docetaxel plus estramustine
have demonstrated more than 50% PSA declines in 59% to 88% of
patients. Although reduction of the dose of estramustine appears to
result in a somewhat lower response rate, the contribution of
estramuxtine to the efficacy of the docetaxel-estramustine
combination was not conclusive.
[0151] Passive Immunization:
[0152] The chemotherapies described above can be combined with
passive immunization against cancer growth promoting factors and
receptors comprises administration of purified antibodies which can
be polyclonal or monoclonal. Monoclonal antibodies are
conventionally prepared for treatment in humanized or chimeric
form.
[0153] The transgenic mouse isolated human antibodies can be
further modified by radiolabel or other toxic materials so as to
induce necrosis or apoptosis in the target cancer cells. For
example, the antibodies, modified or not, will be directed to bind
to receptors, many of which will internalize the ab-receptor
complex to the nucleus of the cell so as to lead to the affected
cell's death, which process may be similar or like apoptosis.
Pancreatic carcinoma treatment can include one or more of the
combinations of chemotherapeutic agents and active or passive
immunotherapies, as described above. However, the treatment are not
in any way limited to the specific aforementioned samples. On the
contrary, the thrust of the invention suggests a useful variety of
combined chemical and immunological agents to slow or decrease
tumor growth.
[0154] Polyclonal antibodies can be obtained from immunized human
and other mammalian sources. One manner of inducing high affinity
specific antisera utilizes the immunogen as described above where
the antigenic varieties are conjugated to immunogenic carrier. The
highly active antibody fractions are isolated and purified by
conventional means for inoculation in the cancer patient in need of
this treatment. Since this type of passive immunotherapy can
utilize the patient's own antibodies, the risk of rejection and
other complications can be minimized or entirely avoided.
[0155] Treatment with modified, such as radioactive-labeled
antibodies is from anti-CCKB/gastrin receptor antibodies would
effect cell death by internalized specific irradiation.
Furthermore, the combination therapy using gastrin and gastrin
receptor immunogens can be administered to immunize or prevent
metastasis of gastrin-dependent adenocarcinoma cells. Such
metastatic cancer cells may derive from gastric, prostate,
pancreatic, or colorectal lesions and localize in other tissues,
such as bone, liver or lymph nodes. Anti-gastrin immunization has
been shown to inhibit liver metasis.
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Sequence CWU 1
1
5 1 17 PRT Homo sapiens PEPTIDE (1)..(17) Amino acid sequence 5
through 21 of the CCK-B/gastrin receptor 1 Lys Leu Asn Arg Ser Val
Gln Gly Thr Gly Pro Gly Pro Gly Ala Ser 1 5 10 15 Leu 2 15 PRT homo
sapiens PEPTIDE (1)..(15) Amino acid sequence of the fourth
extracellular domain of the CCK -B/gastrin receptor 2 Gly Pro Gly
Ala His Arg Ala Leu Ser Gly Ala Pro Ile Ser Phe 1 5 10 15 3 7 PRT
Artificial Sequence Hypothetical synthetic peptide spacer 3 Ser Ser
Pro Pro Pro Pro Cys 1 5 4 17 PRT Homo sapiens PEPTIDE (1)..(17)
Amino acid sequence of Gastrin 17 4 Xaa Gly Pro Trp Leu Glu Glu Glu
Glu Glu Ala Tyr Gly Trp Met Asp 1 5 10 15 Xaa 5 34 PRT homo sapiens
PEPTIDE (1)..(1) XAA = Pyroglutamine 5 Xaa Leu Gly Pro Gln Gly Pro
Pro His Leu Val Ala Asp Pro Ser Lys 1 5 10 15 Lys Gln Gly Pro Trp
Leu Glu Glu Glu Glu Glu Ala Tyr Gly Trp Met 20 25 30 Asp Xaa
* * * * *