Long-term efficacy and safety of bexarotene for Japanese patients with cutaneous T-cell lymphoma: The results of a phase 2 study (B-1201).

The present study (B-1201 clinical trial) was conducted as a multicenter, open-label, single-arm phase II study to evaluate the long-term safety, tolerability and efficacy of bexarotene. This study enrolled 10 Japanese adults aged more than 20 years with cutaneous T-cell lymphoma (CTCL) who completed the 24-week study period of the B-1101 trial. The objective response rate (ORR) was 53.8% (95% confidence interval, 25.1-80.8). In the early stage (IB), the ORR was 60% (3/5 cases). In the advanced stage (IIB and IIIA), the ORR was 57.1% (4/7 cases). The median time to response was 58 days (range, 27-168). The median treatment duration was 380 days (range, 33-1674). The median duration of response (DOR) could not be reached during the study period. The longest DOR reached 1618 days at the end of the B-1201 trial. Nine patients (56.3%) in the full analysis set (FAS) population experienced dose reduction of bexarotene. Common drug-related adverse events in the FAS population included hypothyroidism (93.8%), hypertriglyceridemia (81.3%), hypercholesterolemia (81.3%), leukopenia (68.8%) and neutropenia (56.3%). Dose-limiting toxicity (DLT) was present in five (38.5%) of the 13 patients in the 300 mg/m cohort. Of the five patients, four developed grade 3 neutropenia and one developed grade 4 hypertriglyceridemia. All DLT cases recovered after the discontinuation of bexarotene. None of the five patients discontinued this trial because of DLT. The B-1201 trial shows the long-term safety of oral bexarotene for Japanese patients with CTCL, despite frequent dose reduction.