Vascular endothelial growth factor receptor 2 (VEGFR2) is an essential factor in tumor angiogenesis and in the growth of pancreatic cancer. Immunotherapy using epitope peptide for VEGFR2 (VEGFR2-169) that we identified previously is expected to improve the clinical outcome. Therefore, a phase I clinical trial combining of VEGFR2-169 with gemcitabine was conducted for patients with advanced pancreatic cancer. Patients with metastatic and unresectable pancreatic cancer were eligible for the trial. Gemcitabine was administered at a dose of 1000 mg ⁄ m 2 on days 1, 8, and 15 in a 28-day cycle. The VEGFR2-169 peptide was subcutaneously injected weekly in a dose-escalation manner (doses of 0.5, 1, and 2 mg ⁄ body, six patients ⁄ one cohort). Safety and immunological parameters were assessed. No severe adverse effect of grade 4 or higher was observed. Of the 18 patients who completed at least one course of the treatment, 15 (83%) developed immunological reactions at the injection sites. Specific cytotoxic T lymphocytes (CTL) reacting to the VEGFR2-169 peptide were induced in 11 (61%) of the 18 patients. The disease control rate was 67%, and the median overall survival time was 8.7 months. This combination therapy for pancreatic cancer patients was tolerable at all doses. Peptide-specific CTL could be induced by the VEGFR2-169 peptide vaccine at a high rate, even in combination with gemcitabine. From an immunological point of view, the optimal dose for further clinical trials might be 2 mg ⁄ body or higher. This trial was registered with ClinicalTrial.gov (no.
2567 Background: The prognosis of pancreatic cancer patients is one of the most dismal of all cancers. Gemcitabine is a potent anticancer drug for pancreatic cancer, however, one should consider that the clinical benefit of anticancer drugs is limited and other potent therapeutic tool is eagerly awaited. Vascular endothelial growth factor (VEGF) is a glycoprotein which is predominantly related to the neoplastic angiogenesis. VEGF-receptor 2 (VEGFR2; Flk-1 and KDR) is an essential target for tumor angiogenesis. We first identify the epitope peptides of vascular endothelial growth factor receptor 2 (VEGFR2) and confirmed that stimulation using these peptides induces CTLs with potent cytotoxicity in HLA class I-restricted fashion. Methods: We proceeded to Phase I clinical trial using gemcitabine and one of these peptides. Patients were sequentially allocated to cohorts of 6 patients per group receiving 0.5, 1.0, 2.0mg of peptides/body. No intra-patient dose escalation was permitted. The eligibility criteria are: being aged between 20- and 80- year old, expecting the survival more than 3 months after the initiation of this treatment, adequate organ function including bone marrow function, and having HLA-A*2402 (A24) genotype. The enrolled patients received 4 cycles of VEGFR2 peptide sc. and 3 cycles of 1,000 mg/m2 gemcitabine weekly. Results: No patients had grade 3 and 4 toxicity, and dose escalation was succeeded without any DLT. CTL response was observed in 50%, 67%, and 67% of 0.5mg, 1.0mg, and 2.0mg cohort, respectively. The delayed type hypersensitivity of the peptide-injection site was recognized in 83%, 67%, and 100% of 0.5mg, 1.0mg, and 2.0mg cohort, respectively. Therefore, we concluded that MTD should be 2.0mg of peptide. Disease control rate (>SD) was 67% (12/18 patients), and one patient had PR. The median survival time was 8.72 months. Conclusions: These results are promising to proceed the pivotal clinical trial, and the randomized phase II/III trial will start in 2009. No significant financial relationships to disclose.
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