G. Gonzalez

A novel cancer vaccine composed of human-recombinant epidermal growth factor linked to a carrier protein: Report of a pilot clinical trial

BACKGROUND There is evidence of a relationship between epidermal growth factor (EGF) and tumor cell proliferation, such as the overexpression of EGF receptor (EGF-R) in different human tumors, which makes this system an interesting target for cancer treatment. Up to now, passive immunotherapy with monoclonal antibodies against the EGF-R has been assayed in clinics. Our approach consists of active immunotherapy with human EGF (hu-EGF). We conducted a pilot clinical trial to define the safety, toxicity and immunogenicity of vaccination with hu-EGF coupled to a carrier protein. PATIENTS AND METHODS Ten patients with histologically-proven malignant carcinomas (colon, lung, stomach and prostate) in advanced clinical stages were enrolled. Patients were immunized twice (on days 0 and 15) with hu-EGF linked to either tetanic toxoid (TT, five patients) or P64K Neisseria Meningitidis recombinant protein (P64k, five patients), intradermically, using aluminium hydroxyde as adjuvant. RESULTS In both groups 60% of patients developed anti-EGF antibody titers without evidence of toxicity. Secondary reactions were very mild, limited to erythema and itching at the site of injection, which disappeared without medication. CONCLUSIONS We conclude that the proposed vaccination with hu-EGF was well tolerated and that antibody titers against self EGF were developed. The results of this trial may be useful in the design of new clinical trials with higher dose immunization protocols and using more effective adjuvants.

Effective Inhibition of the Epidermal Growth Factor/Epidermal Growth Factor Receptor Binding by Anti-Epidermal Growth Factor Antibodies Is Related to Better Survival in Advanced Non -Small-Cell Lung Cancer Patients Treated with the Epidermal Growth Factor Cancer Vaccine

Purpose: Epidermal growth factor (EGF) might be a suitable immunotherapeutic target in non–small-cell lung cancer (NSCLC). Our approach consists of active immunotherapy with EGF. The aim of the study is to characterize the humoral response and its effects on signal transduction in relation with the clinical outcome. Experimental Design: Eighty NSCLC patients treated with first-line chemotherapy were randomized to receive the EGF vaccine or supportive care. EGF concentration in sera, anti-EGF antibodies and their capacity to inhibit the binding between EGF/EGF receptor (EGFR), and the EGFR phosphorylation were measured. Results: Seventy-three percent of vaccinated patients developed a good antibody response, whereas none of the controls did. In good antibody-responder patients, self EGF in sera was significantly reduced. In 58% of vaccinated patients, the post-immune sera inhibited EGF/EGFR binding; in the control group, no inhibition occurred. Post-immune sera inhibited the EGFR phosphorylation whereas sera from control patients did not have this capacity. Good antibody-responder patients younger than 60 years had a significantly better survival. A high correlation between anti-EGF antibody titers, EGFR phosphorylation inhibition, and EGF/EGFR binding inhibition was found. There was a significantly better survival for vaccinated patients that showed the higher capacity to inhibit EGF/EGFR binding and for those who showed an immunodominance by the central region of EGF molecule. Conclusions: Immunization with the EGF vaccine induced neutralizing anti-EGF antibodies capable of inhibiting EGFR phosphorylation. There was a significant positive correlation between antibody titers, EGF/EGFR binding inhibition, immunodominance of anti-EGF antibodies, and survival in advanced NSCLC patients.

Therapeutic Vaccination with Epidermal Growth Factor (EGF) in Advanced Lung Cancer: Analysis of Pooled Data from Three Clinical Trials

We have undertaken the analysis of pooled data from three pilot clinical trials of vaccination with Epidermal Growth Factor (EGF) in patients with advanced non small cell lung cancer (NSCLC), addressing particularly the issue of the relationship between immunization and survival. Eighty-three patients with advanced disease were included in 3 pilot clinical trials and vaccinated with the EGF Vaccine. The trials were designed to evaluate the immunogenicity and safety of the vaccine using different adjuvants, cyclophosphamide pre-treatment or not, and different dosage levels of the vaccine. The vaccine elicited specific anti-EGF antibody titers in 83% of subjects, and 49% developed a good anti-EGF antibody response. The adjuvant, the vaccine dose, and cyclophosphamide pre-treatment significantly influenced immunogenicity. Patients that seroconverted survived significantly longer than patients who did not. Good antibody responders survived significantly longer than poor responders. Pooled results from these trials confirm that vaccination with EGF is safe and immunogenic in advanced NSCLC patients. The association between good antibody responses and survival consistently appeared in every single trial independently of the specific trial designs. Although these were small pilot non-randomized clinical trials not intended to confirm therapeutic effect, the survival of the pooled patient population was statistically greater compared with 163 control patients receiving standard treatment.

Combining an EGF-based Cancer Vaccine With Chemotherapy in Advanced Nonsmall Cell Lung Cancer

An epidermal growth factor (EGF) vaccine was given before and after standard first line chemotherapy to patients with advanced nonsmall cell lung cancer (NSCLC), to investigate the immunologic and clinical results in a phase 1 study. Twenty patients diagnosed with advanced NSCLC were recruited. Two vaccinations were given before the first line of chemotherapy treatment, with subsequent monthly vaccination after concluding chemotherapy. The EGF vaccination dose was increased compared with previous trials; the primary end points were immunogenicity and safety. Anti-EGF antibody titers were more than 20 times higher than those previously obtained, without any increase in adverse events, serum EGF concentration decreased to undetectable levels in all patients. Ninety-two percent of the evaluated patients (n=13) showed an immunodominant antibody response against the central region on the EGF molecule. High percentages of EGF/EGF receptor binding inhibition were observed, which significantly positively correlated with the increased antibody response against the EGF immunodominant region. Survival of the patients in this study correlates positively with antibody titers. This study has shown that combination of EGF vaccination at high dose, with chemotherapy is feasible and well tolerated higher anti-EGF antibody titers and reduction of serum EGF concentration seen; do not entail an increase in severe adverse events. The correlation of survival with antibody titers observed is being confirmed confirmation in a wider and randomized trial currently ongoing.

Chronic Vaccination with a Therapeutic EGF-Based Cancer Vaccine: A Review of Patients Receiving Long Lasting Treatment

Therapeutic vaccines continue to be one of the most active fields in cancer research. However, despite clear evidence of antitumor effect in laboratory animals, and despite the ability of current vaccine candidates to elicit tumor specific antibodies and T-cells in humans, objective responses in the clinical trials are rare. The role of therapeutic vaccines in advanced cancer patients, if any, would be to decrease the rate of disease progression and to increase survival and quality of life. Due to the redundant regulatory loops contracting the immune response to antigens that cannot be eliminated, such a role would require chronic vaccination, which is at first sight at odds with the classic experience of vaccinology. During the last decade our team has been developing a therapeutic vaccine for advanced lung cancer, which consists in human recombinant Epidermal Growth Factor (EGF) chemically conjugated to a carrier protein from Neisseria meningitides. Several clinical trials have been carried out, showing increase in anti-EGF antibody titters, decrease in plasma EGF concentration and survival advantage in vaccinated patients. In the present paper we review data from 58 patients who were vaccinated monthly for more than one or two years. Long term vaccination was feasible and safe, and there was no evidence of cumulative toxicity. Patients kept high anti-EGF antibody titters during all the time of vaccination, without evidence of immune response exhaustion. Continued vaccination increased the probability to get a high antibody response, which has been previously shown to be, in turn, associated with a better survival. Observations done in this series of patients suggest that long term therapeutic vaccination is a feasible strategy, worth to be further explored in the aim of transforming advanced cancer into a chronic disease.

Cancer Vaccines for Hormone/Growth Factor Immune Deprivation:A Feasible Approach for Cancer Treatment

One of the older and most validated cancer treatments is endocrine therapy. Some tumors are dependent on hormone stimulation for growth, and therefore therapeutic interventions aiming to deprive the cells of the hormone are feasible and have been successful. Tumor growth also depends in some cases on growth factors, so that the concept of hormone-dependence can be extended to growth factors deprivation. Hormone deprivation has been therapeutically achieved up to now by surgical, radiation and chemical means. However, the immune system usually can be manipulated to recognize hormones and growth factors, and in fact some autoimmune diseases exists involving autoantibodies against hormones. The idea of inducing a deprivation of hormones and growth factors by active immunizations is appealing, and initial evidence about the feasibility of this approach is starting to appear in the literature. Clinical trials have been initiated using immunization with human chorionic gonadotrophin (hCG), gastrin, luteinizing hormone releasing hormone (LHRH) / gonadotropin releasing hormone (GnRH) and epidermal growth factor (EGF). Preliminary data already show that antibody titers can be elicited, which results in a decrease in the concentration of a given hormone or growth factor. Both the antibody titers and the decrease in the hormone level are related to survival. This immunological approach for hormone and growth factor deprivation creates the possibility of chronic management of advanced cancer patients.

Safety, immunogenicity and preliminary efficacy of multiple-site vaccination with an Epidermal Growth Factor (EGF) based cancer vaccine in advanced non small cell lung cancer (NSCLC) patients

The prognosis of patients with advanced non small cell lung (NSCLC) cancer remains dismal. Epidermal Growth Factor Receptor is over-expressed in many epithelial derived tumors and its role in the development and progression of NSCLC is widely documented. CimaVax-EGF is a therapeutic cancer vaccine composed by human recombinant Epidermal Growth Factor (EGF) conjugated to a carrier protein, P64K from Neisseria Meningitides. The vaccine is intended to induce antibodies against self EGF that would block EGF-EGFR interaction. CimaVax-EGF has been evaluated so far in more than 1000 advanced NSCLC patients, as second line therapy. Two separate studies were compared to assess the impact of high dose vaccination at multiple anatomic sites in terms of immunogenicity, safety and preliminary efficacy in stage IIIb/IV NSCLC patients. In both clinical trials, patients started vaccination 1 month after finishing first line chemotherapy. Vaccination at 4 sites with 2.4 mg of EGF (high dose) was very safe. The most frequent adverse events were grade 1 or 2 injection site reactions, fever, headache and vomiting. Patients had a trend toward higher antibody response. The percent of very good responders significantly augmented and there was a faster decrease of circulating EGF. All vaccinated patients and those classified as good responders immunized with high dose at 4 sites, had a large tendency to improved survival.

Therapeutic vaccination with an EGF-based vaccine in lung cancer: a step in the transition to a chronic disease

The trend of increased survival in advanced tumors suggests the possibility of the transformation of cancer into a chronic disease. That goal will require therapeutic weapons with low toxicity that can be used chronically. Here we summarize the development of a therapeutic vaccine consisting in recombinant EGF chemically linked to a protein from Neisseria meningitides. In mice, the vaccine elicited antibodies to self-EGF and had anti-tumor activity. Clinical trials have shown that the vaccine is also immunogenic and well tolerated in humans. The vaccination produced a decrease in plasma EGF concentration. Advanced lung cancer patients eliciting high antibody titers of EGF had better survival. The vaccine can be used long term and integrated with other treatment modalities.

Therapeutic vaccination with epidermal growth factor (EGF) in advanced lung cancer: Analysis of pooled data from three clinical trials

2548 Background: During the last 10 years we have studied the effect of vaccination against self EGF, both in the preclinical setting, and in several pilot clinical trials in advanced non-small cell lung cancer (NSCLC) patients. Here, we undertake the analysis of aggregated data from these trials, addressing particularly the issue of the relationship between immunization and survival. METHODS Pooled data from 3 pilot clinical trials in 75 patients, considered not amenable to any other modality of onco-specific treatment, were used. For survival analysis, 27 NSCLC patients were considered as a non-randomized concurrent control group. This group of patients has features which make it adequate for comparison: compliance with inclusion criteria, simultaneity in time, and treatment in the same hospital by the same physician staff. Vaccination using different adjuvants (alum and Montanide ISA51), cyclophosphamide pre-treatment or not, as well as different dosages of the Vaccine were compared. RESULTS On vaccinated patients, 80% showed seroconversion, of which 47% developed a good antibody (Ab) response. Geometric mean of maximal Ab titers was 1:3949 (sera dilution). Adjuvant, vaccine dose and cyclophosphamide pre-treatment significantly influenced immunogenicity whereas the other analyzed variables (sex, age, clinical stage, previous treatment) did not. The immune response was short lasting (2.64 +/- 1.89 months) and non-boostable. To maintain Ab titers continuous re-immunizations were required. No serious adverse events were registered. Vaccinated patients survived significantly more (mean: 9.13 months; median: 8 months) than the control group (mean: 4.85 months; median: 4.53 months) (p=0.0003). Patients who seroconverted survived significantly more than patients who did not. Patients with good Ab response showed a significant improvement in survival as compared with those with poor Ab response. CONCLUSIONS Vaccination with EGF was safe, immunogenic and improved survival in advanced NSCLC patients as compared with concurrent controls. These results are currently being verified in a randomized trial. No significant financial relationships to disclose.