New therapeutic options for hairy cell leukemia

Hairy cell leukemia (HCL) is a rare B-cell lymphoproliferative disorder characterized by pancytopenia, splenomegaly and increased susceptibility to infections. In 2011, BRAF gene mutation was identified in almost all the patients with the classical type of HCL. The purine analogs cladribine and pentostatin induce long-term remission in the majority of patients, and they remain the standard treatment for this type of leukemia. However, more than half of patients in complete response relapse over the long term, with a quarter of them relapsing within the first five years. Recently, new drugs have been developed and have demonstrated efficacy in refractory or relapsed HCL. The immunotoxin Moxetumomab pasudotox was registered for HCL in 2018. The BRAF kinase inhibitors vemurafenib and dabrafenib, as well as the Bruton kinase inhibitor ibrutinib, are also proven highly effective in clinical trials.