Phase 2 trial of talabostat and cisplatin in patients with stage IV melanoma

Abstract

8040 Background: Talabostat (TAL) is an oral inhibitor of dipeptidyl peptidases such as fibroblast activation protein found on the stroma of tumors, draining lymph nodes, and in melanomas. TAL up-regulates cytokines and chemokines, leading to specific T-cell immunity and T-cell independent activity. TAL significantly enhances the activity of cisplatin (C) in mice, and reduces tumor size >60% in melanoma xenografts (A375, A2058). This trial evaluated the activity of TAL and C in patients with Stage IV melanoma. Methods: Open-label, single-arm, Phase 2 study of 4 x 3-week cycles of C-75mg/m2 (Day 1) and TAL-300mcg BID orally on Days 2–15 with dose-escalation to TAL-400mcg BID depending on tolerability. Single-agent TAL could be continued beyond 4 cycles until disease progression or unacceptable toxicity. Eligibility criteria included: ≤1 prior bio- or chemotherapy regimen, ECOG 0–2, measureable disease per RECIST, no symptomatic CNS metastases, LDH, ALT, and AST <3X ULN. Primary endpoint was disease response; secondary endpoints included PFS, duration of response, and survival. Results: 74 patients (50 men, 24 women) entered the study; median age was 58 years (range 27 to 79); 94.6% were caucasian. Most patients (71.4%) were M1c, and the majority (64.3%) had received at least 1 prior regimen; 72.9% of these had received prior cytokine treatment. A PR was reported in 5/42 evaluable patients (11.9%), and SD for at least 4 cycles in an additional 21/42 (50%). Median PFS and survival are currently estimated at 2.6 months (95% CI 2.1, 3.4) and 8.5 months (95% CI 5.4, infinity), respectively in the ITT population. Most frequent AEs were nausea (46%), fatigue (35%), and vomiting (34%); the high unevaluability rate patients was due to non-compliance related to C-associated N/V (thus the dose of C was reduced mid-study from 100 to 75mg/m2). Grade 3 toxicities were neutropenia, fatigue, and dehydration, all at 3.4%. Grade 4 toxicities were organ failure, renal failure, and PD (1 patient each). 4 patients died due to PD, and 1 each due to renal and organ failure. Conclusions: The combination of TAL and C is active in patients with Stage IV melanoma. Most AEs were related to C-associated nausea and vomiting, limiting the oral delivery of TAL. Additional studies of TAL in melanoma with other drug combinations are warranted. [Table: see text]