Multicenter phase 2 trial of vemurafenib plus obinutuzumab as frontline therapy for hairy cell leukemia

Hairy cell leukemia (HCL) is a B-cell lymphoproliferative disorder characterized by a high prevalence of the BRAF-V600E mutation. A multicenter phase 2 trial in the United States evaluated the combination of vemurafenib (BRAF inhibitor) and obinutuzumab (anti-CD20) as frontline therapy for HCL. Among 30 patients, 27 patients completed all four cycles of treatments and achieved complete remission, and 26 patients achieved MRD negativity. At a median follow-up of 34.9 months, no patient experienced disease relapse. The most common vermurafenib-related adverse events were rash and arthralgia. Febrile neutropenia occurred in two patients, and two patients required blood or platelet transfusions. Patients were not observed long enough to reveal secondary malignancies.