Phase I/II Study of Multiple-Vaccine Therapy Using Epitope Peptide Restricted to HLA-A*2402 in Treating Patients With Refractory Gastric Cancer

URLC10 and KOC1 have been identified as cancer specific molecules especially in non small cell lung cancer using genome-wide expression profile analysis by cDNA microarray technique. In a prior study, it has been shown that URLC10 and KOC1 are upregulated in human gastric tumors. VEGF receptor 1 and 2 are essential targets to tumor angiogenesis, and we identified that peptides derived from these receptors significantly induce the effective tumor specific CTL response in vitro and vivo. According to these findings, in this trial, we evaluate the safety, immunological and clinical response of those peptides. Patients will be vaccinated twice a week for 8 weeks. On each vaccination day, the URLC10 peptide (1mg), KOC1 peptide (1mg), VEGFR1 peptide (1mg) and VEGFR2 peptide (1mg) mixed with Montanide ISA 51 will be administered by subcutaneous injection. The patients will also receive oral chemotherapy (S-1) simultaneously. Repeated cycles of vaccine will be administered until patients develop progressive disease or unacceptable toxicity, whichever occurs first. In the phase I study, we evaluate the safety and tolerability of these peptide vaccines. In the following phase II study, we evaluate the immunological and clinical response of this vaccine therapy.