Phase II assessment of talabostat and cisplatin in second-line stage IV melanoma

BACKGROUND: Metastatic melanoma is an incurable disease with an average survival of less than one year. Talabostat is a novel dipeptidyl peptidase inhibitor with immunostimulatory properties. METHODS: This phase II, open label, single arm study was conducted to evaluate the safety and efficacy of 75-100 mg/m2 cisplatin combined with 300-400 mcg talabostat bid for 6, 21-day cycles. The primary endpoint was overall response. The rate of complete responses, duration of overall objective response, progression-free survival (PFS), and overall survival were the secondary endpoints. RESULTS: Six objective partial responses were recorded in the 74 patients (8.1%) in the intention-to-treat population. Five of these responses involved the 40 evaluable patients (12.5%). Thirty-one percent of patients reported SAEs to the combination of talabostat and cisplatin. CONCLUSION: Acceptable tolerability was observed in the intention-to-treat population and antitumor activity was observed in 12.5% of evaluable patients, which is not greater than historical expectation with cisplatin alone.