Romidepsin in Japanese patients with relapsed or refractory peripheral T-cell lymphoma: a phase I/II and pharmacokinetics study

This phase I/II multicenter study evaluated romidepsin treatment in Japanese patients with relapsed/refractory peripheral T-cell lymphoma (PTCL) or cutaneous T-cell lymphoma (CTCL). Patients aged ≥20 years received romidepsin via a 4-h intravenous infusion on days 1, 8, and 15 of each 28-day cycle. Phase I used a 3 + 3 design to identify any dose-limiting toxicity (DLT) for regimens of romidepsin 9 and 14 mg/m². The primary endpoints for phase I and II were DLT and overall response rate (ORR), respectively. Intent-to-treat patients were those who received ≥1 romidepsin dose (PTCL, n = 48; CTCL, n = 2). In phase I, none of the patients (n = 3, 9 mg/m²; n = 6, 14 mg/m²) exhibited DLT. In phase II, 40 patients with PTCL were treated with 14 mg/m² romidepsin. The most common treatment-emergent grade ≥3 adverse events were lymphopenia (74%), neutropenia (54%), leukopenia (46%), and thrombocytopenia (38%). Patients in phase II showed a 43% ORR, including 25% complete responses. Median progression-free survival was 5.6 months and median duration of response was 11.1 months. This phase I/II study identified a well-tolerated dose of romidepsin, with an acceptable toxicity profile and clinically meaningful efficacy in Japanese patients with relapsed/refractory PTCL.