[Romidepsin (Istodax ® for intravenous injection 10 mg): pharmacokinetics, pharmacodynamics and clinical study outcome].

Romidepsin (Brand name: ISTODAX® for Injection 10 mg) is a novel antitumor drug that inhibits histone deacetylase (HDAC). Romidepsin strongly inhibited class I HDAC activity in vitro and demonstrated a strong antitumor activity against human tumor cell line xenograft in vivo. Based on its demonstrated efficacy against T-cell lymphoma in early clinical studies, multicenter phase II clinical studies in overseas with romidepsin were conducted in patients with cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL), followed by approval for the treatment of CTCL and PTCL in the U.S. and other countries. Thereafter, domestic phase I/II studies were planned. The phase I study was designed to evaluate the tolerability of romidepsin in Japanese patients with relapsed or refractory PTCL/CTCL and thereby determine the recommended dose, as patients were administered romidepsin by intravenous infusion at a dose of 9 or 14 mg/m2 over 4 hours on days 1, 8 and 15 of each 28-day cycle, and 14 mg/m2 was determined as the recommended dose for phase II. While the phase II study was designed to include 40 Japanese patients with relapsed or refractory PTCL to evaluate the efficacy and safety of romidepsin. Treatment response was 42.5% and the most common AEs of Grade ≥ 3 were lymphopenia (74.0%), neutropenia (54.0%), leukocytopenia (46.0%) and thrombocytopenia (38.0%). The overall safety profile was considered to be within the acceptable range. On the basis of these result, romidepsin was approved in July 2017 for the treatment of relapsed or refractory PTCL in Japan.