Journal Article

Mixed 20-peptide cancer vaccine in combination with docetaxel and dexamethasone for castration-resistant prostate cancer: a randomized phase II trial

Suekane Shigetaka, Ohyama Chikara, Uemura Hirotsugu, Naito Seiji, Egawa Shin, Nakagawa Masayuki, Eto Masatoshi, Yamada, Akira, Nasu Yasutomo, Matsumoto Kazumasa, Kakuma Tatsuyuki, Shichijo Shigeki, Noguchi Masanori, Arai Gaku, Sasada Tetsuro, Itoh Kyogo

2020

Overview

A novel cancer vaccine consisting of 20 mixed peptides (KRM-20) was designed to induce cytotoxic T lymphocytes (CTL) against twelve different tumor-associated antigens. The aim of this phase II trial was to examine whether KRM-20 in combination with docetaxel and dexamethasone enhances the antitumor effects in patients with castration-resistant prostate cancer (CRPC). In this double-blind, placebo-controlled, randomized phase II study, we enrolled chemotherapy-naïve patients with CRPC from ten medical centers in Japan. Eligible patients were randomly assigned 1:1 centrally to receive either KRM-20 combined with docetaxel and dexamethasone (n = 25) or placebo with docetaxel and dexamethasone (n = 26). The primary endpoint was the difference in prostate-specific antigen (PSA) decline between each treatment. The rates of > 50% PSA decline in the two arms were similar (56.5% versus 53.8%; P = 0.851). Human leukocyte antigen (HLA)-matched peptide-specific immunoglobulin G (P = 0.018) and CTL (P = 0.007) responses in the KRM-20 arm significantly increased after treatment. The addition of KRM-20 did not increase toxicity. There were no between-group differences in progression-free or overall survival (OS). The addition of KRM-20 was safe, and similar PSA decline and HLA-matched peptide-specific CTL and IgG responses increased in combination with docetaxel and dexamethasone in CRPC patients. Subgroup analysis suggested that this treatment is favorable for CRPC patients with ≥ 26% lymphocytes or PSA levels of < 11.2 ng/ml, but further clinical trials comparing OS are required.

• Publisher: Springer Nature B.V
• Subject: Antigen (tumor-associated) / Antigens / Antitumor activity / Cancer vaccines / Castration / Chemotherapy / Clinical trials / Cytotoxicity / Dexamethasone / Histocompatibility antigen HLA / Immunoglobulin G / Immunotherapy / Lymphocytes T / Patients / Peptides / Placebos / Prostate cancer / Prostate-specific antigen / Steroids / Vaccines