Peptide vaccine helpful for HLA-A2-positive patients with prostate cancer.

2004 MAR 31 - (NewsRx.com & NewsRx.net) -- Peptide vaccination is helpful in HLA-A2-positive patients with metastatic hormone-refractory prostate cancer.

"To evaluate the safety and toxicity of peptide vaccination for patients with metastatic hormone-refractory prostate cancer (HRPC) based on pre-existing peptide-specific cytotoxic T-lymphocyte (CTL) precursors in the circulation, 10 patients positive for human leukocyte antigen (HLA)-A2 with metastatic HRPC were enrolled in a phase I study. Peptide-specific CTL-precursors reactive to 16 kinds of vaccine candidates in the pre-vaccination peripheral blood mononuclear cells (PBMCs) were measured, and patients were followed by vaccination with only positive peptides (up to four kinds of peptides). Serum prostate-specific antigen (PSA) levels were monitored regularly," investigators in Japan report.

"The peptide vaccination was safe and well tolerated with no major adverse effects," said Masanori Noguchi and colleagues at Kurume University. "The most common toxicities were dermatologic reactions at the injection site. Increased CTL response to peptides was observed in 4 of 10 patients. Anti-peptide IgG was also detected in post-vaccination sera of 7 of 10 patients. One patient showed the disappearance of a pelvic bone metastasis after five vaccinations. Three patients showed a decrease of serum PSA level from the baseline after the ...