Low-Dose Vemurafenib Plus Rituximab in Front-Line and Relapsed or Refractory Hairy Cell Leukemia: The Scripps Regimen

Area of Science:

• Hematology
• Oncology
• Pharmacology

Background:

• Purine nucleoside analogues are standard HCL treatments but cause myelosuppression.
• Traditional vemurafenib dosing (960 mg BID) often requires dose reductions.
• Targeted therapy with BRAF inhibitors and anti-CD20 antibodies shows promise for HCL.

Purpose of the Study:

• To evaluate the efficacy and safety of low-dose vemurafenib plus rituximab in HCL patients.
• To assess hematologic recovery, response rates, and MRD negativity.
• To determine tolerability in treatment-naïve and relapsed/refractory HCL.

Main Methods:

• Prospective observational study of 15 HCL patients.
• Low-dose vemurafenib (240 mg BID for 8 weeks) plus rituximab (375 mg/m² every 2 weeks for 14 weeks).
• Assessed hematologic recovery, overall response, MRD negativity, and toxicities.

Main Results:

• All patients achieved complete hematologic recovery.
• 87% overall response rate (73% complete response), with 53% MRD negativity at 6 months.
• No grade 3-4 toxicities or deaths observed; favorable tolerability.

Conclusions:

• Low-dose vemurafenib plus rituximab is effective and well-tolerated for HCL.
• This regimen induces rapid hematologic recovery in treatment-naïve and relapsed/refractory HCL.
• Further investigation into this combination for HCL treatment is warranted.