Fifty years of hairy cell leukemia treatments

Treatment of hairy cell leukemia (HCL), a disease first described in 1958, has evolved from splenectomy, which resulted in a normalization of blood counts in about 41% of patients and an improvement in the remaining 59% of patients but with a time to failure of only approximately 19 months, through treatment in the early 1980s with interferon, which resulted in the same high overall response rate but with a time to failure of approximately 31 months. Subsequently, therapy with either pentostatin or cladribine showed an increase in the complete remission (CR) rate to approximately 80-90%, with only a small percentage of patients relapsing at approximately 30 months. More recently, patients who have failed either or both of these drugs have been shown to respond to rituximab or the experimental drug, BL22 (HA22). With these documented successes, the outlook for patients diagnosed with HCL, 50 years after the disease was first described, is so positive that patients with HCL have survival curves similar to those for the appropriate age-related cohorts.