Treatment of hairy-cell leukemia: Current views

Although hairy-cell leukemia (HCL) is uncommon, remarkable progress has been made in the treatment of patients with this disease. Because of their unique mechanisms of action, the purine analogs, 2'-deoxycoformycin (2'-DCF) and 2-chlorodeoxyadenosine (2CdA), are naturally targeted to lymphocytes and are cytotoxic to both resting and dividing cells. Both of these agents induce durable complete remissions (CRs) in the overwhelming majority of patients. Remarkably, equally high rates of durable CR are achieved in both untreated and previously treated patients. Furthermore, patients with large tumor burdens fare as well as those with minimal disease. Therefore, these agents have emerged as the treatments of choice for all patients with hairy-cell leukemia and have supplanted earlier treatments such as splenectomy and interferon-α (IFN-α). Since a single 7-day cycle of 2-CdA leads to excellent outcomes and is associated with few toxicities other than culture- negative fever, this agent is particularly attractive and may offer some advantages. However, given the indolent natural history of HCL, long-term follow-up study will be required to determine if one purine analog offers a survival advantage over the other.