This is a single-center, open label, single arm, investigator-initiated phase II trial of the oral BRAF inhibitor, vemurafenib, plus rituximab in patients with previously untreated or relapsed and refractory HCL. Eligible patients will receive vemurafenib at a dose of 240 mg orally twice daily (b.i.d.) continuously for 8 weeks. Rituximab 375 mg/m2 will be administered concomitantly with vemurafenib every 2 weeks from the first day of treatment. After completion of vemurafenib, the patient will receive rituximab 375 mg/m2 every 2 weeks for a total of 8 weeks. The entire duration of treatment will be 16 weeks. Six months after the initiation of the treatment, a peripheral blood flow cytometry and a bone marrow aspirate and biopsy will be performed for assessment of response and evaluation of minimal residual disease (MRD).
The current standard-of-care for Hairy Cell Leukemia involves chemotherapy, with agents such as cladribine or pentostatin. Chemotherapy is associated with infection, low blood counts and predisposition to future cancers. This study tests a new drug combination for the treatment of hairy cell leukemia. The treatment involves 8 weeks of treatment with an oral drug called vemurafenib and 8 doses of an intravenous medication called rituximab. The goal of this study is to see whether this treatment is better tolerated and more effective than the currently used treatment in this disease. In addition, this study uses a lower dose of vemurafenib than previous studies have used, with the goal of minimizing side effects from this medication.