Abstract
BACKGROUND: TAS0313 is a multi-epitope long peptide vaccine targeting several cancer-associated antigens highly expressed in multiple cancer types, including glioblastoma (GBM). This cohort of a Phase 2 part evaluated the efficacy and safety of TAS0313 in patients with GBM. METHODS: TAS0313 (27 mg) was administered subcutaneously on Days 1, 8 and 15 of Cycles 1 and 2, and Day 1 of subsequent cycles in 21-day cycles. The primary endpoint was the objective response rate (ORR). The secondary endpoints were the disease control rate, progression-free survival (PFS) and 6- and 12-month progression-free survival rates (PFR) and safety. Immunological response was assessed as an exploratory endpoint. RESULTS: The best overall response was partial response in 1 patient, and the ORR (95% CI) was 11.1% (0.3-48.2%) in the per-protocol set (n = 9). A further 3 patients achieved stable disease, for a disease control rate (95% CI) of 44.4% (13.7-78.8%). Median (95% CI) PFS was 1.7 (1.3-NE) months and 6- and 12-month PFRs (95% CI) were 22.2% (3.4-51.3%) each. Common (≥ 20% incidence) treatment-related adverse events (AEs) were injection site reactions (n = 8, 80.0%), followed by pyrexia (n = 7, 70.0%), and malaise, injection site erythema and injection site pruritus (n = 2, 20.0% each). There were no grade 4 or 5 treatment-related AEs. No deaths occurred during the study. In some patients, TAS0313 treatment was confirmed to increase cytotoxic T lymphocyte and immunoglobulin G levels compared with baseline. CONCLUSION: TAS0313, a multi-epitope long peptide vaccine, demonstrated promising efficacy and acceptable safety in patients with recurrent GBM. CLINICAL TRIAL REGISTRATION: JapicCTI-183824 (Date of registration: Jan 11, 2018).