Mogamulizumab for relapsed adult T‐cell leukemia–lymphoma: Updated follow‐up analysis of phase I and II studies

Summary The present study sought to elucidate the prognosis of adult T-cell leukemia–lymphoma (ATL) patients receiving mogamulizumab, a defucosylated anti-CCR4 monoclonal antibody. Progression-free survival (PFS) and overall survival (OS) of ATL patients enrolled in two studies are updated here, namely NCT00355472 (phase I study of mogamulizumab in relapsed patients with ATL and peripheral T-cell lymphoma) and NCT00920790 (phase II study for relapsed ATL). Of 13 patients with relapsed aggressive ATL in the phase I study, four (31%) survived > 3 years. For 26 relapsed patients with aggressive ATL in the phase II study, median PFS was 5.2 months and 1-year PFS was 26%, while median OS was 14.4 months, and 3-year OS was 23%. For patients without a rash or who developed only a grade 1 rash, median PFS was 0.8 months, and 1-year PFS was zero, with a median OS of 6.0 months, and 3-year OS of 8%. In contrast, for patients who developed a rash ≥ grade 2, median PFS was 11.7 months, and 1-year PFS was 50%, with a median OS of 25.6 months, and 3-year OS of 36%. Thus, we conclude that mogamulizumab monotherapy may improve PFS and OS in some patients with relapsed aggressive ATL, especially those who develop a skin rash as a moderate immune-related adverse event. Therefore, further investigation is warranted to validate the present observations and to clarify the mechanisms involved in the activity of mogamulizumab. This article is protected by copyright. All rights reserved.