Current treatment strategies for patients with hairy cell leukemia

Hairy cell leukemia is uncommon, but recent developments in treatment have improved the outcome. Splenectomy was the preferred treatment for many years until the efficacy of interferon was clearly demonstrated. Currently, the purine analogs have emerged as the treatments of choice. 2-Chlorodeoxyadenosine (2-CdA) is resistant to the action of adenosine deaminase. Since this agent generally is administered as a single 7-day course with a paucity of toxicities, many investigators have suggested it is the preferable agent. However, the outcome associated with 2-CdA has never been compared to 2-deoxycoformycin in a prospective randomized trial. Therefore, it is not known whether one or the other agent is associated with improved long-term outcome. The new immunotoxin, BL22, which is a fusion of an anti-CD22 antibody linked to a portion of the Pseudomonas exotoxin A, has proved to be very effective for patients who have failed or are refractory to the purine analogs. The role of this agent as initial therapy for newly diagnosed patients has not been explored.