ASH 2023: Durable Responses Observed with Valemetostat Tosylate Treatment in Relapsed/Refractory Peripheral T-Cell Lymphoma

Treatment options for relapsed or refractory peripheral T-cell lymphoma (PTCL) are limited, and many patients experience an aggressive disease course. In the phase 2 VALENTINE-PTCL01 study, the safety and efficacy of the novel drug valemetostat tosylate – approved for the treatment of relapsed/refractory adult T-cell leukemia/ lymphoma (ATLL) in Japan – was investigated in patients with relapsed/refractory PTCL. Primary results from this study were presented by LRF Scientific Advisory Board member Steven Horwitz, MD of Memorial Sloan Kettering Cancer Center.

Patients in the VALENTINE-PTCL01 study had received a median 2 prior lines of therapy (range, 1 to 12). The median duration of treatment in the study was 18 weeks, with a median follow-up of 10.5 months. At the time of analysis, 24.1% of patients were still receiving treatment; 34.6% discontinued treatment due to disease progression or relapse, and 9.8% discontinued due to adverse events. Other reasons for treatment discontinuation were clinical progression (14.3%) and progression to allogeneic stem cell transplant (9.0%).

Among 119 patients evaluated in the study, the overall response rate was 43.7%; 17 patients (14.3%) achieved a complete response and 35 (29.4%) achieved a partial response. Overall response rate was similar across all PTCL subtypes observed. The median duration of response was 11.9 months. Median progression-free and overall survival were 5.5 months and 17.0 months, respectively.

The most common treatment-emergent adverse events in the study were cytopenias, with thrombocytopenia representing the most common overall and grade ≥3 adverse events. Serious adverse events occurred in 39.8% of patients, and 65.4% of patients experienced an adverse event leading to a dose reduction or interruption.

This study also included contributions from Philadelphia Lymphoma Rounds Steering Committee member Stefan Barta, MD, MRCP, MS of University of Pennsylvania; and LRF grantee Neha Mehta-Shah, MD of Washington University in Saint Louis.