Retrospective analysis of valemetostat for relapsed or refractory adult T-cell leukemia-lymphoma

The prognosis of patients with relapsed or refractory adult T-cell leukemia-lymphoma (R/R ATL) is poor. Valemetostat is an orally available selective inhibitor of enhancer of zeste homologue (EZH) 1 and 2. A retrospective study at three centers in Japan evaluated valemetostat for R/R aggressive ATL. The overall response rate and complete response rate were 54.2% and 33.3%, respectively. With a median follow-up of 19.2 months (range 7.3-21.7), the median progression-free survival was 8.3 months and the median overall survival was 15.8 months, with 1-year PFS rate 44.1% and 1-year OS rate 55.8%. Notably, the probability of 1-year OS was 90.9% in patients with achieved complete or partial response, compared to 17% in patients who did not achieve complete or partial response. The authors conclude that valetometostat might be a valuable therapy for R/R aggressive ATL.