Long-term outcomes in patients with relapsed or refractory hairy cell leukemia treated with vemurafenib monotherapy

Shivani Handa, Jeong Ok Lee, Andriy Derkach, Richard M. Stone, Alan Saven, Jessica K Altman, Michael R. Grever, Kanti R. Rai, Madhulika Shukla, Shreya Vemuri, Skye Montoya, Justin Taylor, Omar Abdel-Wahab, Martin S. Tallman, Jae H. Park*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Vemurafenib, an oral BRAF inhibitor, has demonstrated high response rates in relapsed/refractory (R/R) hairy cell leukemia (HCL). However, little is known about long-term outcomes and response to retreatment. Herein, we report the results of 36 patients with R/R HCL treated with vemurafenib from the United States arm of the phase 2 clinical trial (NCT01711632). The best overall response rate was 86%, including 33% complete response (CR) and 53% partial response (PR). After a median follow-up of 40 months, 21 of 31 responders (68%) experienced relapse with a median relapse-free survival (RFS) of 19 months (range, 12.5-53.9 months). There was no significant difference in the RFS for patients with CR vs PR. Fourteen of 21 (67%) relapsed patients were retreated with vemurafenib, with 86% achieving complete hematologic response. Two patients acquired resistance to vemurafenib with the emergence of new KRAS and CDKN2A mutations, respectively. Six of 12 (50%) responders to vemurafenib retreatment experienced another relapse with a median RFS of 12.7 months. Overall survival (OS) was 82% at 4 years, with a significantly shorter OS in patients who relapsed within 1 year of initial treatment with vemurafenib. Higher cumulative doses or a longer duration of treatment did not lengthen the durability of response. All adverse events in the retreatment cohort were grade 1/2 except for 1 case of a grade 3 rash and 1 grade 3 fever/pneumonia. Our data suggest that vemurafenib retreatment is a safe and effective option for patients with R/R HCL.

Original languageEnglish (US)
Pages (from-to)2663-2671
Number of pages9
Issue number25
StatePublished - Dec 22 2022

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology


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