Phase II Study: Valemetostat Tosylate Effective, Safe in Relapsed or Refractory PTCL

A multi-center phase II study found that valemetostat tosylate (valemetostat) has favorable efficacy and manageable safety in patients with relapsed or refractory peripheral T-cell lymphoma. The study was led by Pier Luigi Zinzani, MD, of the University of Bologna, Italy, and its findings are published in The Lancet Oncology.

This open-label single-arm study, VALENTINE-PTCL01, enrolled 133 patients with relapsed or refractory peripheral T-cell lymphoma, who had a median age of 69 years and were 68% male. It also enrolled 22 patients with relapsed or refractory adult T-cell leukemia or lymphoma, who had a median age of 66.5 years and were 68% male. All patients received oral valemetostat dosed at 200 mg per day in continuous 28-day cycles until disease progression or unacceptable toxicity.

In the study, efficacy was evaluated specifically in the patients with peripheral T-cell lymphoma. These patients had a median follow-up time of 12.3 months, and of 119 evaluable patients, 44% had an objective response.

Adverse events were evaluated in all patients enrolled in the study. The most prevalent grade 3-4 adverse events that occurred among the 133 patients with peripheral T-cell lymphoma were thrombocytopenia at 23%, anemia at 19%, and neutropenia at 17%. Among the 22 patients with adult T-cell leukemia or lymphoma, the most prevalent were thrombocytopenia at 50%, anemia at 46%, and neutropenia at 18%.

Serious treatment-emergent adverse events were reported by 40% of all patients with peripheral T-cell lymphoma and 68% of patients with adult T-cell leukemia or lymphoma. Experience of a serious treatment-emergent adverse event related to treatment was reported by 7% of patients with peripheral T-cell lymphoma and 5% of patients with adult T-cell leukemia or lymphoma. There were no treatment-related mortalities reported in the study.

The VALENTINE-PTCL01 study was funded by Daiichi Sankyo.

Reference

Zinzani PL, Izutsu K, Mehta-Shah N, et al. Valemetostat for patients with relapsed or refractory peripheral T-cell lymphoma (VALENTINE-PTCL01): a multicentre, open-label, single-arm, phase 2 study. Lancet Oncol. 2024;25(12):1602-1613. doi:10.1016/S1470-2045(24)00503-5