Successful re-treatment of a relapsed V600E mutated HCL patient with low-dose vemurafenib.

Caroline Bailleux,Isabelle Sudaka,Daniel Re,Patrick Auberger,Antoine Thyss,Guillaume Robert,Frederic Peyrade,Clémence Ginet,Paul Hofman,Isabelle Peyrottes

doi:10.18632/oncoscience.111

Abstract

Hairy cell leukemia (HCL) is a chronic B-cell lymphoproliferative disorder that accounts for 2% of all leukemia. Recent identification of the recurrent V600E BRAF mutation in a majority of HCL patients has led some teams to evaluate the clinical potential of vemurafenib, a BRAF V600 specific inhibitor in a limited number of refractory HCL patients. Recently, we published the case of an HCL patient successfully treated with a low dose of vemurafenib. Eight months after the ending of treatment this patient relapsed. We present here the successful retreatment of this patient with a second line of vemurafenib. Our data suggest for the first time that vemurafenib at the dose of 240 mg once a day could be sufficient to maintain a complete hematological remission after an initial induction treatment with low-dose vemurafenib (2 × 240 mg) daily without inducing major toxicity.

Highlights

Hairy cell leukemia (HCL) is a rare chronic B-cell lymphoproliferative disorder that predominantly affects middle-aged males
The presence of 12% BRAF V600E mutation was established by Sanger sequencing in blood leukemia cells at day 308 corresponding to 28% of CD19/CD103 double positive HCL cells
Recent identification of the recurrent V600E BRAF mutation in a huge majority of HCL patients has led some teams to evaluate the clinical potential of vemurafenib a BRAF V600 specific inhibitor

Summary

Introduction

Hairy cell leukemia (HCL) is a rare chronic B-cell lymphoproliferative disorder that predominantly affects middle-aged males (sex ratio 1⁄4). Dietrich et al reported in 2012 a case of refractory HCL treated with increasing doses of vemurafenib an ATP-competitive BRAF V600 inhibitor that has been shown to have potent antitumor activity in BRAF V600 mutated melanomas [3]. This drug was shown to exhibit remarkable activity at high doses (480 mg 4x/day) on both splenomegaly and blood counts. We presented the case of a refractory HCL patient treated with low dose of vemurafenib (240 mg 2x/day) and leading to complete remission [5]. We present a successful re-treatment schema of a relapsed V600E mutated HCL with low-dose vemurafenib

Methods

Results

Conclusion