EZH1 and EZH2 inhibitor DS-3201b in relapsed adult T-cell leukaemia/lymphoma

A multicentre single-arm phase 2 study in Japan of valemetostat, an oral inhibitor of the histone methyltransferases EZH2 and EZH1, in relapsed or refractory aggressive adult T-cell leukaemia/lymphoma. The primary endpoint was overall response assessed centrally by an independent committee.

Twenty-five patients were enrolled, median age 69, with a median of three prior lines; 24 had already received mogamulizumab. The overall response was 48.0 per cent (90 per cent confidence interval 30.5 to 65.9), five complete and seven partial remissions, and 45.8 per cent in those previously treated with mogamulizumab. The median duration of response had not been reached. Adverse events in at least 20 per cent included thrombocytopenia, anaemia, hair loss, altered taste, neutropenia, lymphopenia, leukopenia, decreased appetite and fever. OnCo holds no drug record for valemetostat, so it is named here and not linked.