Advances in the Treatment of Hairy Cell Leukemia Variant

Opinion statement Hairy cell leukemia variant (HCL-V) is a rare B cell lymphoproliferative disorder with a clinical-pathological distinction from the classic form of hairy cell leukemia (HCL-C). HCL-V is more aggressive in nature, has a higher tendency to be refractory to conventional purine analog pharmacotherapies, and leads to a poorer prognosis. Hence, these differing features bring paramount importance to the diagnosis and management of HCL-V. While there is no genetic mutation diagnostic of HCL-V, genetic profiling efforts have identified potential therapeutic targets (i.e., MAP2K1, KDM6A, CREBBP, ARID1A, CCND3, U2AF1, KMT2C) and yielded prognostic markers (i.e., IGHV4-34 rearrangements). To date, combination chemoimmunotherapies, such as cladribine and rituximab, have shown the best results in HCL-V. Future directions include targeted therapies such as moxetumomab pasudotox, ibrutinib, trametinib, and binimetinib and potentially anti-CD22 chimeric antigen receptor T cell therapy. The purpose of this review is to provide an outline of the diagnostic approach and an update on the therapeutic advancements in HCL-V.

Automated summary

Hairy cell leukemia variant (HCL-V) is a rare and aggressive B cell lymphoproliferative disorder with distinct clinical and pathological features from classic hairy cell leukemia (HCL-C). It has a higher likelihood of being refractory to conventional purine analog therapies and leads to a poorer prognosis. While there is no specific genetic mutation diagnostic of HCL-V, genetic profiling has identified potential therapeutic targets and prognostic markers. Combination chemoimmunotherapies have shown the best results in HCL-V, but targeted therapies and CAR-T cell therapy are being explored for future advancements.