Fludarabine and rituximab for relapsed or refractory hairy cell leukemia.

The purine analogs, pentostatin and cladribine, induce high remission rates when used as first-line monotherapy for hairy cell leukemia (HCL); however, patients continue to relapse. Re-treatment with the same or alternate purine analog produces lower response rates and a shorter duration of response. Fludarabine is another purine analog widely used in indolent lymphoid cancers, often in combination with rituximab, but there are few reports of its use in HCL. We identified 15 patients treated in British Columbia with fludarabine and rituximab (FR) from 2004 to 2010 for relapsed/refractory HCL after first-line cladribine (n = 3) or after multiple lines of therapy (n = 12). All patients with available response data responded to FR. With median follow-up of 35 months, 14 patients remain progression-free, whereas 1 patient has developed progressive leukemia and died. Five-year progression-free and overall survivals are 89% and 83%, respectively. FR is a safe and effective therapeutic option for relapsed/refractory HCL.