An old but still good friend: chemoimmunotherapy in HCL

In this issue ofBlood, Schroeder et al 1 from the Kreitman team at the National Cancer Institute build on their already strong track record in clinical research on hairy cell leukemia (HCL) by reporting valuable prospective data on 2 chemoimmunotherapy regimens, DCFR (pentostatin [alias deoxycoformycin (DCF)] plus rituximab) and BR (bendamustine + rituximab), for patients with relapsed or refractory (R/R) HCL.HCL is a rare mature chronic B-cell neoplasm caused by the mutation of BRAF (or extremely rarely, of MAP2K1) that presents at a median age of ~50 to 60 years, usually with cytopenias and splenomegaly.In most cases, patients with HCL respond durably to chemotherapy with purine analogs (PA) (cladribine [CDA] or DCF). [2]3][4] However, this established standard of care does not typically eradicate the disease, and relapses of cytopenias are frequent (at a median of 10 years after therapy).Although retreatment with the same or the alternate PA is usually effective, the disease becomes progressively less sensitive to chemotherapy, with a shorter median duration of response after each relapse. 2