MXPA00011300A - Combination therapy for the treatment of tumors - Google Patents

Abstract

The present invention relates to a combination therapy method for treating gastrin-dependent tumors. The method comprises the immunization of a patient with an anti-gastrin (17) immunogenic composition in combination with the administration of chemotherapeutic agents such as 5-fluorouracil and leucovorin.

Description

COMBINED THERAPY FOR THE TREATMENT OF TUMORS FIELD OF THE INVENTION The invention relates to a teirapia [against] tumors to inhibit growth by neutralization • Immunologically from the peptide hormones that stimulate growth, in combination with a chemotherapy that applies a derivative of 5-Fluorouracil and leucovorin. BACKGROUND OF THE INVENTION Gastrin is a peptide hormone that occurs in two mature forms, tetratriacontagastrina (G34) and heptadecagastrina (G17), and specialized cells, the G cells, located in the stomach antrum, synthesize and secrete. In gastrin-producing cells, these gastrin hormones are processed post-translationally from a common precursor molecule called "preprogastrin" which contains a precursor peptide.

The precursor peptide "pre" is removed in the endoplasmic reticulum of the cell, which gives rise to the peptide "progastrin", which in turn is processed in the cell to produce the mature gastrins ^ G34 and G17, before their secretion into the bloodstream (Dickinson 1991). (The full citations of the references cited here appear in the References section that precedes the Claims). Both mature forms of G34 and G17 are amidated at their carboxy terminal end (-NH2). In humans, multiple forms of G17 caused by the Differential processing of the precursor molecule, each of which may have different biological activities (Dickinson 1995 and Ciccotosto et al., 1995). In the post-translational processing of gastrin, the "mature" carboxyamide form binds to a specific cell receptor, the so-called CCK-B / gastrin receptor, via the carboxy terminus of the peptide (Kopin et al., 1992). Gastrin hormones are secreted in circulating blood and bind to specific cells in the stomach, ie, enterochromaffin-like cells (ECL) and parietal cells, which indirectly or directly affect the production of stomach acid. Historically, both gastrin hormones have been associated with stimulation of secretion • Gastric acid (Edkins, J.S. 1905). In recent years, evidence has accumulated showing that gastrin also acts as a trophic factor within the gastrointestinal tract (Johnson, L. 1997) and that promotes the growth of gastrointestinal cancers (Atson et al., 1989, Dickinson, C.J. 1995), as well as non-gastrointestinal cancers, including a small cell carcinoma of the lung (Rehfeld et al., 1989). . { Various types of tumors, including tumors of the colon and rectum, stomach, pancreatic and hepatocellular adenocarcinomas possess CCK-B / gastrin receptors in their plasma membranes and tumor cells respond to gastrin with vigorous cell proliferation (Rehfelcl, JF 1972, Upp et al., 1989 and Watson et al., 1993). High levels of total gastrin plasma in patients with cancers in the colon and rectum and, in particular, have been detected greater amounts of progastrin hormone precursor in many tumors in the colon and rectum making use of gastrin antisera (Ciccotosto et al . , nineteen ninety five) . More recently, it has been discovered that many of these cancer cells also secrete gastrin and thus create an autonomous proliferative pathway (Van-Solinge et al., 1993, Nemeth et al., 1993 and Seva et al., 1994). . Peptide hormones G17 and G34 bind to CCK-B / gastrin receptors in cell membranes of cells normal. However, it has been detected that G17, but not G34, stimulates the growth of dependent cancer cells • of gastrin. In particular, G17 associated with serum has the potential to stimulate tumor growth in the colon and rectum in an endocrine fashion mediated by CCK-15 B / gastrin receptors in tumor cells (Watson et al., 1993). G17 is particularly involved in stimulating the growth of adenocarcinomas of the colon and rectum due to a possible greater affinity with the CCK-B / gastrin receptors in the cells of the flfe tumors, in comparison with other species of hormones of gastrin (Rehfeld 1972 and 1993). It was detected that CCK-B / gastrin receptors were expressed in a higher affinity form in 56.7% of primary colon and rectum tumors in humans (Upp et al., 1989). Numerous studies have shown that, in addition to being able to Responding to exogenous endocrine gastrin, gastric tumors and in the colon and rectum of humans produce gastrin and its precursors (Ciccotosto et al., 1995; Finley et al., 1993; Kochman et al., 1992; Nemeth et al. 1993, Van Solinge et al., 1993), and in this way produce a path that stimulates autocrine growth. The production of gastrin in tumor cells differs from endocrine G cells. Specifically, such tumor cells contain a high proportion of progastrin precursor together with a lower concentration of mature peptides. It is postulated that this abnormal coefficient is due to a non-regulated constitutive release of gastrin combined with a limited activity of peptidylglycine aminidant monooxygenase Ciccotosto et al. , nineteen ninety five; Kelly • 1985). In this way, the unregulated release of gastrin leads to the abnormal production and secretion of different molecular forms of the hormone. Specifically, colon carcinoma cells do not efficiently process progastrin, which results in a lower conversion of precursor gastrin to mature peptides and, thus, produces mostly incomplete or aberrant gastrins (Dickinson 1993 fl) and Rehfeld et al. , 1993). In addition, the level of gastrin greater in tumors of the colon and rectum are attributed, in part, to the aberrant expression of the gastrin gene in colon and rectum tumor cells (Hoosein et al., 1990, Baldwin et al., 1992 and Finley et al. , 1993). Peptides similar to gastrin have been identified in such cells ((Hoosein et al., 1998, Watson et al. , 1991 and Finley et al. , 1993), and it was confirmed that they were precursor gastrin species (Van-Solinje et al., 1993 and Nemeth et al., 1993). The presence of G17 -administered G17 (G17-NH2) in some cancers of the colon and rectum (Ciccotosto et al., 1995; Van-Solinge ^ 5 et al., 1993) demonstrates that some tumors retain an intact processing path, since that the amidation of gastrin occurs only in secretory granules (Varro et al., 1994). Endogenously produced gastrin also functions as an autocrine growth factor, since it was shown that growth The basal cell line of the colon and rectum was inhibited by an antigastrin antibody [Hoosein et al. , 1988). This was confirmed by a second study in which northern blot analysis revealed gastrin mRNA in the same cell lines and radio immunity analysis revealed immunoreactivity similar to gastrin in a cell culture supernatant (Hoosein et al., 1990). Gastrin peptides also perform paracrine functions (Watson et al., 1991b), which was confirmed (Finley et al., 1993) in experiments that showed a predominant immunoreactivity of gastrin in infrapopulations of malignant mucosal cells in the colon and rectum. When G17 binds to its receptor, a G17 / receptor complex is formed that simulates cell growth through secondary messengers to regulate cell functions (Ullrich et al., 1990). Agglutination of G17 at receptor CCK-B / gastrin leads to an activation of the phosphatidylinositol disintegration, the activation of the protein kinase with a resulting increase in the concentration of intracellular calcium ions, and the induction of the protooncogenes c-fos and cj a through the protein kinase activated by the mitogen, which has been implicated in the VK regulation of cell proliferation (Tadisco et al., 1995). In addition, the agglutination of gastrin to the CCK-B / gastrin receptor has been associated with the further increase in phosphorylation by a tyrosine kinase, ppl25FADK (focal adhesion kinase), which may also have a role in the transmission of these mitogenic signals (Tanaguchi et al., 1994). Cancer in the colon and rectum continues to be a • formidable disease to treat, because in recent years only minor improvements in survival have been achieved. Surgery is an effective treatment of the primary disease, but it is ineffective against residual occult disease, which is often pre. In general, radiation therapy after surgery is recommended for patients with rectal cancers to reduce the risks of recurrence of the disease. Chemotherapy with 5-Fluorouracil (5-FU) has been the most traditional effective therapy after surgery in patients suffering from more advanced cancers of the colon and rectum. However, it has been shown that 5-FU therapy only has a marginal benefit for the patient, since 5-FU is highly toxic and the therapy is expensive and does not seem significantly prolong survival, on its own or in combination with other cytotoxic drugs. In most cases, occult or inoperable tumors in the colon and rectum do not respond well to chemotherapy or radiation, and new treatments are needed to supplement current procedures. Recently, several studies have shown that adjuvant combination chemotherapy with 5-FU and Leucovorin improves the efficacy of 5-FU in patients with cancer of the advanced colon and rectum. Leucovorin is a derivative of folic acid, which is also known as folinic acid, factor Citrovorum, or 5-formyl-5, 6, 7, 8, -tetrahydrofolic acid. Studies show that in patients in stage C of Dukes, the combined therapy of 5-FU / Leucovorin can reduce mortality between 10 and 15% • (Moertel, 1994). In the same group of patients, combined intravenous and intraperitoneal therapy with 5-FU / leucovorin caused a non-significant trend to survival without diseases and a general survival advantage (Scheithauer et al., 1995). In advanced disease, the same combination of drugs may give rise to a survival advantage (Taylor 1993), which has been shown to be 13.5 months Jfc average survival in the group treated with the combination compared with 7.5 months in patients treated with 5-FU (Petrioli et al., 1995). However, this combined chemotherapy is not without significant morbidity and causes deleterious side effects, including stomatitis, diarrhea and myelosuppression (Mahood et al., 1991; Erlichman et al., 1988; Pietnelli et al. , 1989), which makes the quality of life a topic of discussion, especially with patients suffering from advanced disease. Several high-affinity CCK-B / gastrin receptor antagonists both in vi tro and ^ p 5 in vivo have been therapeutically evaluated in several experimental gastrointestinal cancers. For example, proglumide, a glutamic acid derivative (Seva et al., 190 [sic]; Harrison et al., 1990 and Watson et al., 1991a); Benzotript, an N-acyl derivative of tryptophan; L-365,260, a derivative of Aspercillin (Bock et al., 1989); Y CI-988, a molecule that simulates the sequence of C-pentapeptides Conclusions from the CCK (Hughes et al., 1990) have been shown to effectively neutralize the effects of exogenous gastrin on the growth of gastrointestinal tumors both in vi tro and in vivo (Watson et al., and Romani et al. ., 1994). Nevertheless, These antagonists have severe toxic side effects and lack specificity, since they block the action of all potential receptor ligands, such as G34 and CCK in normal cells. Recently, highly potent CCK-B / gastrin receptor antagonists have also been described and selective ones such as YM022 (Yuki et al., 1997) and YF476 (Takinami et al., 1997). Proglumide and Benzotript have been extensively evaluated in preclinical studies. The main problem with these compounds is their lack of power, and they are required relatively high concentrations to displace the G17 (Watson et al., 1992a, Watson et al., 1992b). Notwithstanding the foregoing, proglumide and Benzotript inhibited the basal proliferation of several cell lines stimulated by gastrin (Seva et al., 1990; Watson et al., 1991a). In addition, proglumide increased the survival of xenografts of mice with colon tumor in mice sensitive to gastrin MC26 at 39 days in treated animals, of 25 days in the control animals. Due to the low specificity of this class of gastrin antagonist agents for the gastrin / CCK-B receptor, growth inhibition is also thought to induce gastrin receptor independent action. In addition, cellular receptors that recognize and fix gastrin do not bind to all tested inhibitors (Seva et al., 1994). Therefore, if the complete inhibition of gastrin binding the receptor does not occur in the autocrine growth cascade, gastrin antagonists may be prevented from blocking this mechanism of growth promotion of the tumors. Therefore, new therapeutic proposals are needed both as modalities in their own right and for combination strategies with chemotherapy. Combination treatments offer the possibilities of improving the therapeutic index and / or reducing the dose of chemotherapy needed, and thereby limiting the disadvantageous side effects. A therapeutic method of immunologically and selectively neutralizing the biological activity of the gastrin hormone would offer an effective means of controlling or preventing the pathological changes resulting from the excessive production of gastrin hormones associated with cancers in the colon and rectum. U.S. Patent Nos. 5,023,077, 5,468,494, 5,607,676, 5,609,870 and 5,622,702 disclose immunogens and immunogenic mixtures useful for controlling the levels of G17 and G34 in a patient by generating antigastrin antibodies and also disclosing the use of such mixtures for the treatment of gastric and duodenal ulcers and cancers induced by gastrin. The present invention relates to the use of immunogens and anti-G17 immunogenic mixtures which disclose Patent Nos. 5,023,077, 5,468,494, 5,607,676, 5,609,870 and 5,662,702 in a combination therapy with chemotherapeutic agents for treating colon and rectal cancers dependent on gastrin The anticancer therapy method described in this invention has several advantages over current methods for treating cancers in the colon and rectum. The anti-G17 immunization, combined with chemotherapeutic agents such as 5-FU and Leucovorin, promotes the therapeutic effects to control or inhibit the growth of tumors in the colon and rectum on chemotherapy alone. SUMMARY OF THE INVENTION The present invention offers a combination therapy for treating tumors that comprises immunologically neutralizing peptide hormones and factors that promote the proliferation of tumor cells in combination with chemotherapy. In particular, the present invention offers a method for treating gastrin-dependent cancers, such as adenocarcinomas of the colon and rectum. The method comprises a combination therapy comprising the anti-G17 immunization of the patient in need of therapy, together with the administration of one or more chemotherapeutic agents. Anti-G17 immunization to treat gastrin-dependent tumors is surprisingly effective in the generation of anti-G17 antibodies, notwithstanding the known myelosuppressive effects of the chemotherapeutic agents used. The anti-G17 immunization comprises the active or passive immunization of a patient with an anti-G17 immunogen against the G17 hormone to control the G17 levels of the patient. As a result of the induction of anti-G17 antibodies in a patient, the G17 hormone is neutralized in vivo and its physiological effects are inhibited, and in this way the growth of tumor cells dependent on G17 is inhibited. In addition, the use of anti-G17 immunization in combination with normal chemotherapy increases the efficacy of cancer treatment in the colon and rectum, since in combination, lower amounts of chemotherapeutic agents may be necessary to treat a patient, and that way reduce its toxic effects in normal tissues. In addition, the patient's quality of life can be improved and their survival time can be prolonged.

In a preferred embodiment, the method comprises the active immunization of a mammal suffering from a gastrin-dependent tumor with an anti-G17 immunogen, in combination with the administration of one or more chemotherapeutic agents, such as 5-Fluorouracil, leucovorin, levamisole, cisplatin, tumor necrosis factor and proglumide. The anti-G17 immunogen can be administered to a patient at the start of therapy and at later intervals, as the patient needs. Anti-G17 antibodies produced by the patient after immunization agglutinate and neutralize G17 in its mature amidated G17 form as well as in its precursor forms, for example, G17-Gly, in vivo and prevent agglutination of G17 to its receptors , and in this way prevents the growth of gastrin-dependent tumor cells. The concentrations of anti-G17 antibodies produced by an immunized patient can be controlled at predetermined intervals using standard techniques. In addition, chemotherapeutic agents may be administered as indicated by normal regimens or lower doses may be administered, as the patient requires. In another embodiment, the invention also provides a method of treating a gastrin-dependent tumor comprising passive immunization of a patient suffering from a gastrin-dependent tumor with anti-G17 antibodies in combination with one or more chemotherapeutic agents, such as 5-Fluorouracil [,] leucovorin, levamisole, cisplatin, tumor necrosis factor and proglumide. In a preferred embodiment of this aspect of the invention, the antibodies can be chimeric, humanized or human monoclonal antibodies, which can be produced by methods that are well known in the art. The antibodies can be administered together with the chemotherapeutic agents at the beginning of the therapy and at subsequent intervals after the initial therapy, as the patient needs. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 depicts a graph showing a period of serum antibody concentrations after immunization of rats immunized with 500 μg / ml anti-G17 (1-9) -TD immunogen from rats. Figure 2 depicts a graph showing the effects of a 30 mg / kg dose of 5-FU / leucovorin treatment on the concentrations of anti-G17 (1-9) antibodies obtained in rats immunized with the subject immunogen of the invention . Figure 3 depicts a Scatchard plot showing the effects of the 30 mg / kg treatment cycle of 5-FU / leucovorin on the average counts of white blood cells in BDIX rats. Figure 4 depicts a bar graph showing the average weight of tumors in untreated rats treated with anti-G17 (1-9) TD- and treated with TD.

Figure 5 depicts a bar graph showing average tumor weights of rats treated with 30 mg / kg of 5-FU / leucovorin; 30 mg / kg of 5-FU / leucovorin and immunogen TD; 30 mg / kg of 5-FU / leucovorin and anti-G17 (1-9) TD; 25 mg / kg of 5-FU / leucovorin and TD immunogen; 25 mg / kg of 5-FU / leucovorin and anti-G17 (1-9) TD; 20 mg / kg of 5-FU / leucovorin and immunogen TD; 20 mg / kg of 5-FU / leucovorin and anti-G17 (1-9) TD; 12.5 mg / kg of 5-FU / leucovorin and TD immunogen; and 12.5 mg / kg of 5-FU / leucovorin and anti-G17 (1-9) TD. DETAILED DESCRIPTION OF THE INVENTION The present invention provides methods of treating tumors, in particular those associated with gastrin-dependent colon and rectal cancer, with a combination therapy comprising immunizing a patient with an anti-G17 immunogen and treating the patient with chemotherapeutic agents such as 5-FU and leucovorin. Combination therapy with anti-G17 / 5-FU-leucovorin immunization, surprisingly, has been found to be more effective than previous therapies in the treatment of cancer in the colon and rectum. Chemotherapeutic agents useful in combination therapy do not significantly inhibit the production of anti-G17 antibodies in an immunized patient and lower doses of chemotherapeutic agents can be used to treat tumor growth. In addition, the concentrations of anti-G17 antibodies produced by the immunization are effective to neutralize all forms of the G17 hormone.

In a preferred embodiment, the method comprises actively immunizing a patient suffering from gastrin-dependent colon and rectal cancer by applying an anti-G17 immunogenic mixture while administering chemotherapeutic agents to the patient. Subsequent anti-G17 booster immunizations may be administered as required by the patient, as determined through an analysis of anti-G17 antibody serum concentrations after patient immunization, using standard techniques and normal radiological evaluations of the patient. the tumors. The anti-G17 immunization can also • apply to a patient before tumor surgery. The anti-G17 immunogens comprise a natural or synthetic peptide fragment of the terminal N-amino acids of G17 as the immunosimulating portion of the immunogen. East The peptide fragment is conjugated to an immunogenic carrier such as diphtheria toxoid (TD). In a preferred embodiment of this aspect of the invention, the anti-G17 immunogen comprises the amino-terminal amino acids of G17 from positions 1 to 9, with the amino acid sequence pyroGlu-Gly-Pro-Trp-Leu-Glu-Glu- 20 Glu-Glu, conjugated to diphtheria toxoid. Other suitable immunogenic protein carriers include bovine serum albumin, limpet hemocyanin, hemocyanin, and tetanus toxoid. Immunogens of the invention may also comprise an extension or spacer peptide sequence suitable for projecting the immunosimulator peptide away from the protein carrier and for improving its ability to bind the receptor lymphocytes. A suitable spacer peptide sequence is the amino acid sequence SSPPPPC (Sequence Identifier No.: 2 in the Sequence List). However, other spacer peptides would also be suitable. In a preferred version of this aspect of the invention, the preferred spacer sequence is coupled to the carboxy terminal end of the immunosimulator peptide. Immunogens of the invention are produced by standard techniques and are disclosed in U.S. Patent Nos. 5,023,077, 5,468,494, 5,607,676, 10 5,609,870 and 5,622,702, the materials of which are incorporated herein by reference. ^^ reference. After immunization, the immunogens of the invention produce high affinity neutralizing antibodies to inhibit the effects of G17 in its mature and precursor forms on the growth of tumors in animals. immunized. The anti-G17 antibodies produced agglutinate and neutralize mature G17s and precursors, and thus prevent agglutination of G17 to the receptors in tumor cells and ultimately inhibit the growth of G17 cells. ^ tumors. Immunogens raise antibodies that neutralize both to G17 carboxyamidated and increased by glycine and do not show a cross-reactivity with G34 or CCK. Mixtures in which immunogens are administered for active immunization for the treatment of gastrin-dependent tumors in patients may have a variety of forms. These include, for example, solid, semi-solid and liquid dosage forms, such as powders, liquid solutions, suspensions, suppositories and injectable and infiltrable solutions. The preferred form depends on the desired mode of administration and the therapeutic applications. The mixtures comprise the current immunogens and suitable pharmaceutically acceptable components, and may include other medicinal agents, carriers, adjuvant excipients, etc., which can be mixed using standard procedures. Preferably, the mixtures are in the form of unit doses. The amount of active compound administered for immunization or as a drug at a time, or over a period of time, will depend on the subject being treated, the manner and manner of administration, and the judgment of the attending physician. An effective dose that varies from 0.001 to 2 mg. of the immunogenic mixture is administered to the patient for the treatment of gastrointestinal cancer. The effective dose of the immunogenic mixture is capable of eliciting an immune response in a patient of effective levels of antibody concentrations to agglutinate and neutralize immature G-17 and precursor for one to three months after immunization. After immunization and treatment with chemotherapeutic agents with, for example, 5-FU / leucovorin, of a patient suffering from cancer of the colon and rectum, the effectiveness of the therapy on the tumor is tested by normal clinical procedures, such as ultrasound and magnetic resonance imaging (MRI). to detect the presence and size of tumors, if any. The concentrations of anti-G17 antibodies can also be controlled with a blood sample taken from the patient. Booster immunizations should be applied as needed to maintain an effective antibody concentration. The effective treatment of adenocarcinomas in the colon and rectum dependent on gastrin and other gastrin-dependent cancers such as stomach, liver, pancreatic and small cell carcinomas of the lungs according to this method should give rise to the inhibition of growth of tumors and a reduction in tumor size. For passive immunization, anti-G17 antibodies are administered intravenously to a patient, making use of a pharmaceutically acceptable carrier, such as a saline solution, eg, saline buffer phosphate. The chemotherapeutic agents are administered in recommended doses in normal regimens and can be administered at the start of therapy simultaneously with the anti-G17 immunogen, either before or after immunization. In some cases, you can It will be beneficial to administer the chemo-therapeutic agent both before and after the immunization. Further chemotherapeutic treatments can also be administered as needed by the patient after evaluation through MRI and ultrasound imaging.

The following experiments were carried out to demonstrate the effects of the combination therapy present in cancers of the colon and rectum. EXAMPLE 1 The following experiments were performed to determine the potential clinical benefit offered by anti-G17 (1-9) -TD. The goals of this study were the following: (a) to determine the long-term effect of specific immunization of rats with anti-G17 (1-9) -TD on the histological appearance of the gastrointestinal tract of rats. (b) evaluate the effects of the combinations of 5- • FU / Leucovorin on antibody concentrations created by anti-G17 (1-9) -TD; and (c) determining the therapeutic effect anti-G17 (1-9) -TD 15 and combinations of 5-FU / leucovorin in a rat colon model. Cell Line DHDK12 is a line of tumor cells of the epithelial colon faith (Martin, 1983). The cell line is maintained in a growth medium RPMI 1640 (Gibco, Paisley, Scotland) containing 10% calf fetus serum (FCS, Sigma, Poole, UK) in humid conditions at 37 ° C and 5% C02. Immunogen The anti-G17 (1-9) -TD immunogen consists of residues of amino acid 1-9 of G17 linked by the carboxy terminal to the spacer peptide SSPPPPC (Sequence Identification No.: 1 in the Sequence List), which in turn is conjugated to TD. The immunogen used in these studies was made specifically for rat G17 substituting the epitope of human G17 with the amino-terminal amino acids 9 of the G17 of rats, linked to flK5 through a peptide spacer to diphtheria toxoid (TD). The antiserum created by the anti-G17 (1-9) -TD was designated G17 (1-9): TD anti-ras. Experimental Animals The Unit of Cancer Studies of the University of Nottingham, in the United Kingdom, supplied male BDIX rats and ^^ females, and they were ages of 6 to 10 weeks, and weighed between 340 and 9 420 grams. The rats were housed in pairs and maintained in a cycle of 12 hours of light and 12 hours of darkness at 25 ° C, in 50% humidity. 15 Before each experiment, the animals were grouped to equalize the weight distribution. The sizes of the groups varied from 6 to 13 animals. The guidelines of the Coordinating Committee of Cancer Research of the United Kingdom United (UKKCCCR) throughout all the experiments with animals. Immunization Procedure The anti-G17 (1-9) -TD immunogen for rats was dissolved in a sterile saline solution (0.9%) pH 7.3 at 1 mg / ml. The normuramyl dipeptide adjuvant (Peninsula Labs., Belmont, CA, USA) was added to the conjugate solution to give a final conjugate concentration of between 200 and 500 μg / ml. The aqueous solution was formulated with a fatty vehicle (montanide ISA 703, AMS Seppic Inc., Paris, France) at a coefficient of 1: 2 (v / v) by emulsification. Once placed in a glass syringe that was attached to a second syringe through a three-way stopcock, the mixture was pushed back and forth through the syringes 40 times to form an emulsion. An emulsion containing DT peptide and muramyl dipeptide was also formulated for the control rats. A volume of 200 μl of emulsion (50 μg / per rat) was injected subcutaneously (right side of the experimental animals). The animals were immunized by a single injection or repeatedly at 21-day intervals as noted below. Cytotoxic treatment regimen Rats received 12.5 and 25 mg / kg of 5-Fluorouracil (5-FU, David Bull Labs, Warwick, UK) and 12.5-25 mg / kg Leucovorin (Lederle Labs, Gosport, Hants, UK) administered intravenously (iv) on days 1, 3 and 5, and the cycle was repeated every 4 weeks throughout the duration of the study period (Asao, 1992). The cytotoxic combination was administered to the rats either before or after immunization with anti-G17 (1-9) -TD (200 μg / ml). Start of tumor growth DHDK12 cells were suspended in a sterile phosphate buffer line (PBS, Oxoid, Hants, UK) at a cell concentration of 2.5xl07 / ml. The rats were anesthetized with an intraperitoneal injection of 1 ml of Hypnorm (0.315 ng / ml of phenatanyl citrate and 10 mg / ml fluanison, Jannsen, Berrse, Belgium), Hypnovel (5 ng / ml of midazolam, Roche, Basel, Switzerland) ), and sterile distilled water at a ratio of 1: 1: 5. After a subcutaneous incision (sc) on the right side, a volume of 200 μl of cell suspension was injected into the layer of (Bd abdominal wall muscles and the surgical incision was closed with wound clamps.) Each experimental group was integrated between 6 and 13 animals.Determination of specific antibody levels of rats immunized with the immunogen for anti-G17 (1-9) -10 TD. ^^ To obtain blood samples for analysis, blood was drawn from the tail of the rats at various times throughout the experiment and to the termination thereof through a cardiac puncture under terminal anesthesia.The anti-rat serum levels of G17 were determined by enzyme-linked immunosorbent assay (ELISA). dissolved a conjugate of bovine serum albumin G-7 for rats at 2 μg / ml in 0.1M glycine buffer (pH 9.5) and 25 μl per well was in 96-well plates Immunulon U (Dynatech Labs, Sussex , UK). The wells are incubated overnight at 4 ° C after which the non-absorbed conjugate was rapidly removed and the wells were washed with buffer (9.9% saline, 9.5% Tween-20 [Sigma] 0.02% NaN3 [Sigma ], pH 8.3). This buffer was used for all washing spaces and dilutions reactive. The sera were treated at 10-fold serial dilutions, from a dilution of 1: 100. The positive control was antiserum antiserum G17 (1-9) -TD from animals previously immunized and negative controls were normal rat serum and serum from rats immunized only with TD. All control sera were used in the same dilutions in the test sera. Diluted sera were added to the wells in 25 μl aliquots in the presence or absence of 25 μl / per well of G17-BSA for rats at 199 μg / ml) as a soluble inhibitor. The control well reference points received only 25 μl of assay buffer. The plates were incubated by space of 60 minutes at room temperature before washing ^^ with the analysis buffer. Goat anti-rabies immunoglobulin (H + L-biotin (Zymed, San Francisco, CA, USA) was added to the wells at a dilution of 1: 500., 50 μl / per well and incubated for 60 minutes, in the dark and at temperature atmosphere. After washing, a 1: 100 dilution of avidin-alkaline phosphatase (Zymed)) (59 μl / per well) was added and the plates were incubated for 60 minutes at room temperature. After further washing, p-1? Nitrophenylphosphate (pNPP) substrate was added to the wells at 50 μl / well and then After a five minute development time, the absorbance at 405 nm was read. Absorbance excellence between untreated sera and sera co-incubated with G17-BSA for rats was calculated at absorbance. Determination of white cell counts of the blood.

Heparinized blood was collected from the rats through bleeding from the tails during the experiment and by cardiac puncture at the end of the experiment. The numbers of white blood cells were analyzed by the Department of Hematology of the University Hospital in Nottingham, with the use of a FACScan tomograph. Histology At the termination [killing] of the long-term immunized rats with anti-G17 (1-9) -TD, representative areas 10 of the stomach, colon and rectum of the immunized rats and corresponding age controls were dissected out and fixed. with formalin The sections were then embedded in paraffin and sections of 4 μm were cut by the use of a microtome. These were stained with hematoxylin and eosin and evaluated by a histopathologist who had no knowledge of the treatment groups. Rhythm of proliferation of crypt cells One hour before the termination [killing] of the ^ fc animals, vincristine (2 mg / kg, Sigma) was injected via intraperitoneal to induce metaphase arrest in the colon epithelium before the valuation of colon crypt cell proliferation (CCPR). The number of metaphase cells was counted per crypt. The colon and rectum of each rat were removed, they were opened longitudinally and the mucosa was fixed of each in a Carnoys solution. The crypts were gently macerated, longitudinally, under a microscope to dissect and the number of metaphase cells was enumerated (increase x 25). Statistical analysis Live results were analyzed using a non-parametric Mann Whitney test with the use of the SPSS statistical package for the IBM personal computer. Long-term anti-G17 (1-9) -TD study Five male rats were immunized with the anti-G17 (1-9) -TD immunogen for rats as ribed above, and their antibody concentrations were measured for 34 weeks after a single immunization. At this point, the rats were boosted with a second injection of [immunogen] anti-G17 (1-9) -TD. Figure 1 shows the results. The figure 1 shows the period of up to 40 weeks after the immunization with rat antibody titers immunized with 500 μg / ml of [immunogen] anti-G17 (1-9) -TD for rats. Each point represents an individual animal. Antibody concentrations were measured by a? Jk ELISA analysis as ribed above, making use of a dilution of serum at 1: 100. The date indicates the immunizations.

After the primary immunization, 4 of the 5 rats responded to the anti-G17 (1-9) -TD immunogen for rats. The antibodies, after this single injection, were detectable at week 7 in 3 of the 5 rats and in 4 of the 5 rats at the week 9. This initial increase in antibodies was followed by a second increase between weeks 15 and 20, after which the antibody concentrations were reduced steadily and by week 34 they approached zero. At this point, Figure 1 also shows that after a second immunization with [immunogen] anti-G17 (1-9) -TD for rats, all rats? 5 had concentrations of anti-G-17 antibodies for detectable rats, at 1 to 2 weeks after immunization. EXAMPLE 2 Histological Analysis of Rats Immunized Long-Term with [Immunogen] Anti-G17 (1-9) -TD 10 After being stained with hematoxylin and esoin as ribed in EXAMPLE 1, specimens from the stomach, from the colon and rectum are evaluated histologically. These specimens were compared with the specimens of corresponding age and sex control rats. All areas of the appliance The gastrointestinal tests evaluated were identical in rats treated with the anti-G17 (1-9) -TD immunogen and of corresponding ages in relation to the height of the villus / crypts / mucous membranes. In the stomach, enterochromaffin-like cells (ECL) were similar in number and appearance in the two groups of animals subject. However, there was some granulation testing of the G cell in the stomach mucosa of the rats treated with [the immunogen] anti-G17 (1-9) -TD. EXAMPLE 3 Proliferation rate of cells in the crypts (CCPR) of the colon epithelium of long-term immunized rats with [the immunogen] anti-G17 (1-9) -TD.

The CCPR of the colon epithelium and the anti-G17 concentrations for rats were analyzed as ribed above. Table I shows the results obtained from 4 out of 5 rats evaluated by comparing the CCPR with the concentrations of anti-G17 antibodies for rats. The average CCPR for the control rats was 18.93 (standard deviation of 3.2) and for the rats immunized with [the immunogen] anti-G17 (1-9) -TD of 23.7 (standard deviation 7.9). There was no statistical difference in the CCPR between the rats immunized with [the immunogen] anti-G17 (1-9) -TD and the corresponding age control rats. These results indicate that the rate of cell division of crypts in the colon epithelium is the same for the controlled rats and the rats immunized with [immunogen] anti-G17 (1-9) [-] TD. Table I. Comparison of the concentrations of anti-G17 antibodies: TD for rats with the proliferation of cells of the colon crypts.

EXAMPLE 4 Effect of pre and post-cytotoxic treatment on the levels of antibodies created by [immunogen] anti-G17 (1-9) - TD for rats A rat was injected intravenously with a 1: 1 ratio of 5-FU / Leucovorin to 30 mg / kg as described in Example 1 before or after immunization with [immunogen] anti-G17 (1-9) -TD. Each group was composed of 6 male rats and 6 female rats per group and mean antibody concentrations were measured by an ELISA technique. using a dilution of sera at 1: 100. Antibody levels in each rat were measured based on blood samples as described in Example 1. Figure 2 shows the effect of pre- and post-cytotoxic treatment with 30 mg / kg cycles of 5-FU / Leucovorin in concentrations of antibodies created by immunization with [the immunogen] anti-G17 (1-9) -TD (500 μg / ml). In the Figure, the data is represented as follows: - < - without cytotoxins, 7 immunizations; . - two immunizations before 4 'cytotoxic treatments; --D-- an immunization before 4 cytotoxic treatments; -? a cytotoxic before 4 immunizations (2 cytotoxic treatments during immunizations); -? - 2 cytotoxic treatments before 4 immunizations; - * - 3 cytotoxic treatments before 3 immunizations and --D-- 4 cytotoxic treatments before 2 immunizations.

Figure 2 shows the average of 6 female rats and 6 male rats per group. Normal deviations were around 10% of the mean. There was no significant effect on antibody concentrations by pretreatment with the 5-FU / Leucovorin cytotoxic combination at any of the antibody levels achieved or the time taken to achieve such levels when compared to untreated rats immunized with [ immunogen] anti-G17 (1-9) -TD. The maximum number of treatment cycles evaluated was 4 cycles of 10 cytotoxic treatment followed by 2 immunizations. • Figure 3 shows the effects of treatment on the mean counts of white blood cells (WBC) in BDIX rats. The effect of cytotoxic treatment with 30 mg / kg of 5 FU / Leucovorin in BDIX rats receiving 4 treatments cytotoxic before 2 immunizations on the mean counts of white blood cells (WBC) is shown in Figure 3.

As shown in the Figure, there was a significant reduction in the WBC counts in the representative k rats evaluated, post-cytotoxic treatment (p < 0.005, test-t of Students). The counts were reduced by the number of cycles of cytotoxic treatments, indicative of myelosuppression. However, there was no effect on the antibody response to [immunogen] anti-G17 (1-9) -TD produced by the rats, as shown in Figure 2. EXAMPLE 5 Effect of the combined therapy of 5-FU / Leucovorin and [immunogen] anti-G17 (1 -9) -TD on the live growth of DHDK12 tumors. The effects of combination therapies with 5-FU / Leucovorin (12.5-30 mg / kg) and [the immunogen] anti-G17 (1-9) -TD for rats (200μg / ml) on colon tumor growth rats of the DHDK12 cell line in the muscular or muscle layer of the abdominal wall of the BDIX rats were tested by comparing them to the tumors in tested animals, just as is described in the previous Examples. At the end of the therapies, the rats were killed, their tumors were removed and weighed • using normal procedures. Each group was composed of between 10 and 12 rats / groups of mixed sex. The average weights of the tumors are shown with the scopes interquartiles above the columns. Statistical evaluation was performed with a non-parametric Mann Whitley U test, as described in Example 1. Figures 4 and 5 show the effects of immunization with [the immunogen] anti-G17 (1-9) -TD about the weights means of the final tumor of BDIX rats to which DHDK12 tumor cells were implanted in the muscle / muscle layer of the abdominal wall. This route of implantation causes a well vascularized tumor receptive to the therapies administered in the circulation (Watson, nineteen ninety six) . Previously, the antigen [immunogen] 25 G17 (1-9) -TD for rats had been shown to inhibit the final weight of the DHDK12 tumor by 56.5% when administered at a dose of 500 μg / ml (Watson, 1996). In the present experiments, to detect the benefits of the combination therapy with 5-FU / Leucovorin, the dose of [immunogen] antiG17 (1-9) -TD was reduced to 200 μg / ml, which gave rise to a significant inhibition of tumor growth of 25.7% as shown in Figure 4. Figure 4 shows data of tumors excised from untreated control rats, rats immunized with the [immunogen] anti-G17 (1-9) -TD and immunized rats with TD. After a period of 50 days, the untreated rats offered a mean tumor weight of 4.43 grams. The immunization with TD caused a mean tumor weight of 4.7 grams, which did not turn out to be significantly different from the tumor weights of the untreated rats, but which was found to be significantly greater than the mean weight of the tumors of the rats immunized with the [immunogen] anti-G17 (1-9) -TD (3.49 g, p = 0.034, Mann Whitney). Figure 5 shows that 5-FU / leucovorin alone, applied at 30 mg / kg, significantly reduced the tumor weight to a measure of 1.01 grams (p = 0.0106 when compared to the ^ | control rats not treated). When the rats were treated with the same cytotoxic dose along with immunization with TD, the mean weight of the tumor did not turn out to be significantly different (0.945 grams). A combination of 5-FU / Leucovorin at 30 mg / kg and immunization of rats with [immunogen] anti-G17 (1-9) -TD originated a mean tumor weight of 0.68 grams, which was not significantly different from the group treated with 5-FU / Leucovorin / TD (p = 0.27). The combination of 25 mg / kg of 5-FU / Leucovorin and immunization with TD yielded a mean tumor weight of 0.96 grams, compared to a mean tumor weight of 0.68 grams in the [rats] immunized with [the immunogen] anti- G17 (1-9) -TD together with the combination therapy group 5-FU / Leucovorin that was not significant (p = 0.409). When the dose of 5-FU / Leucovorin was reduced to 20 mg / kg, the immunogen combination 5-FU / Leucovorin / TD yielded a mean tumor weight of 1.23 grams. The mean weight of the tumor was significantly reduced to 0.71 grams when 20 mg / kg of 5-FU / Leucovorin were combined with immunization with [the immunogen] anti-G17 (1-9) -TD (p = 0.027, Mann Whitney) . Finally, Figure 5 also shows that a dose of 5-FU / Leucovorin of 12.5 mg / kg combined with anti-G17 immunization (1-9) -TD (p = 0.015, Mann Whitney) reduces the mean tumor weight of 1.34. grams to 0.41 grams. The combinations of 5-FU / Leucovorin- [immunogen] anti-G17 (1-9) -TD were compared and there was no significant statistical difference between the [immunogen] anti-G17 (1-9) -TD given in combination with either 12.5, 20 or 30 mg / kg of 5-FU / Leucovorin. Due to the limited benefit shown for combination chemotherapy with 5-FU / Leucovorin in both an advanced cancer state and, in particular, with an adjuvant therapy treatment environment (Moertel, 1994; Scheithauer, 1995; Taylor, 1993; Petrioli, 1995), it may be necessary to give new therapeutic modalities together with 5-FU / Leucovorin to improve the therapeutic index (and possibly reduce the chemotherapeutic dose to limit the toxicity) or as a second-line treatment if the chemotherapy is not effective. Therefore, the new treatments should be suitable for such 5 uses. Previously, proposals or immunotherapeutic approaches (os) together with chemotherapy were considered problematic due to myelosuppression associated with chemotherapeutic agents, as observed with 5-FU / Leucovorin (Mahood, 1991). However, in the present study the Myelosuppression of the rats induced with combinations of 30 mg / kg of 5-FU / Leucovorin administered according to Asao et al. , at the maximum tolerated dose, did not affect the level of and time to achieve anti-G17 antibody concentrations: TD for rats after immunization with the anti- 15 G17 (1-9) -TD immunogen. In the therapeutic studies that make use of 5-FU / Leucovorin in combination with [the immunogen] anti-G17 (1-9) - TD, potentiation of the doses of 20 mg / kg and 12.5 flfe mg / kg was achieved . The dose of 20 mg / kg was as effective as the dose Maximum tolerated when combined with [the immunogen] anti-G17 (1-9) -TD and the dose of 12.5 mg / kg showed a trend towards a greater therapeutic effect. The reason for the latest trend is unknown, but it may be due to the cytotoxic dose that affects the immune system to a lesser degree than higher dose levels. that can help in the general inflammatory response against the tumor. The 5-FU / Leucovorin given in continuous cycles would seem to exert an "all or nothing" effect on tumor growth just as the dose reduction at one mg / kg was found to have no inhibition of tumor growth. The therapeutic effect can be concentrated more gradually by reducing flpd the number of toxic cycles (Watson, personal communication) . Therefore, in the combinations according to the present invention, doses of 5-FU / Leucovorin lower than the usual doses can be administered, and in this way reduce the side effects of the drugs, at the same time as they can effectively annihilate the tumor cells by making use of the present combination, since the immune system is only minimally affected. In this way, the inhibitory effect of the growth of immunization [with immunogen] anti-G17 (1-9) -TD is increased. These characteristics of the combination therapy are unexpected and surprising by virtue of the myelosuppressive effects of the chemotherapeutic agents themselves. In addition, due to the absence of deleterious effects in the host, immunization with [the immunogen] anti-G17 (1-9) -jflfc TD is likely to become such a long-term treatment and as shown by the length of time that measurable / measurable antibody levels were present in rats that received a single immunization. The first immunization was found to be effective 80%, in terms of induction of antigastrin antibodies, and 100% effective after second immunization with an immediate increase in antibody levels. Although the enhancement of chemotherapy can be achieved by a single injection of [immunogen] anti-G17 (1-9) -TD, in the majority of hosts the absence of side effects, characteristic of immunization [with the immunogen] anti-G17 (1-9) -TD and the response rate to the hosts after the boosters indicate that a multiple injection regimen may be desirable. Despite the length of time that the anti-G17 antibodies for rats remained in the circulation, it does not appear that there were long-term deleterious effects in the gastrointestinal tract, as determined by a simple histological evaluation. In addition, the rate of crypt cell proliferation of mucosal cells in the colon did not reveal a significant effect on their growth. EXAMPLE 6 Treatment of human colon cancer patients with a combination therapy of 5-FU / Leucovorin and [immunogen] anti-G17 (1-9) -TD. It has previously been shown that immunization [with the immunogen] anti-G17 (1-9) -TD itself was a valuable and safe therapeutic option in the treatment of gastrin-dependent cancer. The present combinations of anti-G17 immunogens with 5-FU / Leucovorin improve the effectiveness of cancer treatment, in particular the treatment of colon cancer, and the possible reduction in the dose of the chemotherapeutic agent necessary in the combination should reduce the side effects deleterious cytotoxic of any of the chemotherapeutic agents currently used. The present combinations of an immunogen with chemotherapeutic agents may also prove useful as a second line therapy in patients who do not respond to chemotherapy alone. Patients with human colon and rectal tumors or colon cancer are treated with a combination of chemotherapy and immunotherapy. Specifically, patients suffering from tumors of the colon and rectum or colon cancer that respond to gastrin can be treated with the concomitant administration of 5-FU / Leucovorin and a mixture of anti-G17 immunogen or anti-G17 antibodies. In particular, preferred immunotherapy offers an immunogenic mixture comprising a conjugate of amino terminal peptide G17 (1-9): TD in a pharmaceutically acceptable carrier which may include an adjuvant to further stimulate the immune response. The preferred immunotherapeutic regimen may begin before, during or after the course of chemotherapy, depending on clinical considerations. For example, in a patient with a large tumor burden it may be advantageous to start with several cycles of chemotherapy to reduce the mass of the tumor and then start immunotherapy. Alternatively, in a patient with a small tumor load or after curative surgery, immunotherapy may be initiated before or during chemotherapy.

The dose of active immunization can vary from 300 μg to 1200 μg of the anti-G17 immunogen, depending on the condition in terms of patient immunization (or the ability of an immune response). The injection intervals can be days 1, 7 and 14, or days 1, 14 and 21, or days 1, 14, then 28 and 56. All programs can give rise to similar antibody concentrations. Accelerated immunization programs offer the possibility of an early onset of the immune response. 10 The preferred method of antigastrin therapy provides for a booster to be administered every six months after the period • Initial immunization, regardless of what protocol is used. Another preferred method for the effective neutralization of G17, GlyG17 and G17 NH2, provides a passive immunization with anti-G17 antibodies, preferably in purified form. More specifically, the inoculation of 10-1000 μg anti-G17 antibodies (1-9) is administered before, during and / or after the cycles of chemotherapies for the control of gastrin activities. f Passive immunization can be given daily, weekly or biweekly. Other protocols may be followed depending on the effectiveness of the treatment. Another combination of treatment provides for an initial passive immunization before and / or during the first cycle of chemotherapy followed by active immunization as described above.

Many chemotherapy regimens are in use. These regimes recognized in the art, although not described in this invention, are not excluded from the combined treatment according to this invention. A preferred chemotherapy regimen fl5 has an intravenous bolus of 5-FU of 425 mg / m2 with intravenous infusion of leucovorin (folic acid, FA, 20 mg / m2) for one to five days per period, up to four weeks. Another preferred regimen provides 200 mg / m2 of FA over a period of two hours, followed by 10 intravenous boluses of 5-FU of 400 mg / m2 + 5-FU of 600 mg / m2 over 22 hours one or two days in a period of two weeks. Another preferred regimen provides for continuous infusion of 5-FU at 250-300 mg / m2 per day, continuous intravenous for four to six weeks, followed by a two-week rest.

REFERENCES ASAO T. TAKAYUKI A, SHIBATA HR, BATIST G and BRODT P.

Eradication of Hepatic Metastases of Carcinoma H-59 combination chemoimmunotherapy with Liposomal Muramyl Tripeptide, 5-Fluorouracil, and Leucovorin. Cancer Research 52: 6254-6257, 1992. BALDWIN G. Binding of the progastrin fragments to the 78kDa gastrin-binding protein. FEBS Lett 1995; 359: 97-100. ERLICHMAN C, FINE S, WONG A, ELHAKEIM T. A randomized trial of fluorouracil and folinic acid in patients with metastatic CRC. J Clin Oncol 1988; 6: 496-475. MAHOOD DJ, DOSE AM, LOPNIZ CC. Inhibition of Fluorouracil stomatitis by oral cryotherapy. J. Clin Oncol 1991; 9; 449-452. MAKISHIMA R, LARKIN D, MICHAELI D, GAGINELLA TS.

Active immunization against gastrin-17 with an N-terminus derived from inhibited gastrin and duodenal lesions in rats. Gastroenterol 1995; 106: A824. MARTIN F, CAIGNARD A, JEANNIN JF, LECLERC A, MARTIN M. Selection of trypsin of 2 sublines of rat colon cancer cells forming progressive or regressive tumors. Int. J Cancer 1983; 32: 623-627. MOERTEL GG. Chemotherapy CRC. NEJM 1994; 330: 1136-1142. PETRIOLI R, LORENZI M, AQUINO A, MARSILI S, FREDIANI B, PALAZZUOLI V, MARZOCCA G. Treatment of advanced colorectal cancer with high-dose intensity folinic acid and 5-Fluorouracil plus supportive care. Eur J Cancer 1995; 31A: 2105-2108. PIETNELLI N, DOUGLAS HO, HARRAVA L. The modulation of Fluorouracil with leucovorin in metastatic CRC: a prospective randomized phase III trial. J Clin Oncol 1989; 7: 1419-1426. SCHEITHAUER W, KORNEK G, ROSEN H, SEBESTA C, MARCELL A, KWASNY W, KARALL M, DEPISCH D. Combined intreperitoneal plus intravenous chemotherapy after curative resection for colonic adenocarcinoma Eur J Cancer 1995; 31A: 1981-1986. 10 SEVA C, DICKINSON CJ, SAWADA M, YAMADA T.

Characterization of the glycine-extended gastrin (G-gly) receptor • on AR4-2J cells. Gastroenterol 1995; 108: A742. TAYLOR, I. Chemotherapy, raaiotherapy and immunology of colorectal neoplasia. Current opinion in Gastroenterology 15 1993; 9: 28-33. WATSON SA and STEELE RJC. Gastrin receptors in gastrointestinal tumors. WG Landes Company, Austin, USA, 1993. WATSON SA, MICHAEL D, GRIMES S, MORRIS T, ROBINSON G, VARRO A, JUSTIN TA, HARDCASTLE JD. Gastrimmune raises antibodies • 20 that neutralize amidated and glycine-extended gastrin-17 and inhibits the growth of colon cancer. Cancer Res 1996; 56: 880-885.

LIST OF SEQUENCES < 110 > APHTON CORPORATION < 120 > Combined therapy for the 5 < 130 > 1102865-0034 • < 140 > US < 141 > 1999-05-14 10 < 150 > US 60 / 085,687 < 151 > 1998-05-15 < 160 > 2 15 < 170 > Patentln Ver. 2.0 < 210 > 1 < 211 > 9 ___20 < 212 > PRT • < 213 > human or synthetic peptide < 220 > < 221 > MOD RES 25 < 222 > (1) < 223 > pyroglutamic acid < 400 > 1 Glu Gly Pro Trp Leu Glu Glu Glu Glu 30 1 5 210 > 2 211 > 7 35 212 > PRT 213 > Artificial sequence < 220 > < 223 > Description of the artificial sequence: synthetic P'tptido 40 < 400 > 2 Being Pro Pro Pro Pro Cys 1 5

Claims (9)

1. CLAIMS We claim the following: 1. A combination of therapeutic ingredients designed to fight gastrin-dependent tumors and that • comprises: (i) an immunogen directed to combat the growth of gastrin-dependent tumors; and (ii) one or more chemotherapeutic agents.
2. 2. The combination of claim 1, wherein the immunogen comprises a therapeutically effective amount of an immunogen containing a G17 antigastrin peptide.
3. 3. The combination of claim 2, wherein the G17 antigastrin immunogen is conjugated to a diphtheria toxoid.
4. 4. The subject combination of claim 2, wherein the G17 antigastrin immunogen also comprises a spacer peptide.
5. The combination of claim 2, wherein the G17 antigastrin immunogen comprises a peptide consisting of ^ of the amino acid sequence pGlu-Gly-Pro-Trp-Leu-Glu-Glu-Glu-20 Glu (Sequence Identification Number: 1 in the Sequence List).
6. The combination of claim 2, wherein the chemotherapeutic agent is selected from the group consisting of 5-Fluorouracil, leucovorin, levamisole, cisplatin, 25 the tumor necrosis factor, and proglumide.,
7. 7. The combination of any one of claims 1 to 6, which likewise comprises a pharmaceutically acceptable carrier.
8. 8. The use of the combination claimed in the terms of any of claims 1 to 7 for the treatment of a gastrin tumor in a patient.
9. 9. The use, for processing, of the subject combination of any of claims 1 to 7.