Phase I clinical study of a personalized peptide vaccination available for six different human leukocyte antigen (HLA-A2, -A3, -A11, -A24, -A31 and -A33)-positive patients with advanced cancer.

The majority of peptide-based cancer vaccines under development are for human leukocyte antigen (HLA)-A2- or -A24-positive patients. To overcome this limitation, we conducted a phase I clinical study of peptide vaccines designed for cancer patients with six different HLA-A types. Eligible patients were required to have failed prior standard cancer therapies and to be positive for the HLA-A2, -A24 or -A3 (A3, A11, A31 and A33) supertype. Three sets of 8 candidate peptides (24 peptides in total) were provided for vaccination to HLA-A2(+), HLA-A24(+) and HLA-A3(+) patients, respectively. Personalization of the vaccination peptides from the candidate pool was made by considering the patients' HLA types and pre-existing levels of IgGs to the candidate peptides. Seventeen patients were enrolled in this study. The peptide vaccinations were well tolerated in all patients with no vaccine-related severe adverse events. Augmentation of cytotoxic T lymphocyte (CTL) or IgG responses specific to the vaccinated peptides was observed in 11 or 10 out of 13 cases tested, respectively. This new type of vaccine is recommended for phase II clinical trial because of its tolerability and the immune responses to the vaccinated peptides.