LONG-LASTING COMPLETE REMISSION IN PATIENTS WITH HAIRY-CELL LEUKEMIA TREATED WITH 2-CDA - A 5-YEAR SURVEY

Between January 1991 and January 1994, 40 patients with hairy-cell leu kemia (HCL), 30 males and 10 females, with a median age of 54 years, w ere treated with a single course of 2-chlorodeoxyadenosine (2-CdA) at a dose of 0.1 mg/kg/day continuous infusion for 7 days. Thirteen patie nts were untreated and 27 had previously received alpha-interferon. Th irty out of 40 patients (75%) achieved complete remission (CR) and 10 (25%) partial remission (PR). The median follow-up duration for patien ts in CR has been 48 months (range 30-66). Five of the complete respon ders (17%) relapsed at 12, 24, 26, 30 and 36 months after treatment as documented by the increase of hairy cells (Hc) in the bone marrow and two of them, who were retreated with 2-CdA after showing an initial i mpairment of peripheral blood values, obtained a second CR. The remain ing three relapsed patients were never retreated and still show normal peripheral counts after 30, 38 and 40 months. Twelve of the continuou s complete responder patients are still in CR after more than 5 years. In contrast, 8 out of 10 partial responders progressed after 8-36 mon ths and all of them were retreated with 2-CdA at a dose of 0.15 mg/kg/ day for 5 days i.v. Four of them (50%) achieved a CR, three a better P R and one patient died 6 months after the second 2-CdA course because of infectious complications. Two additional patients, both in CR, died after 28 and 37 months because of a second neoplasm. Toxic side-effec ts consisted of febrile episodes recorded in 16 patients: in seven of them, fever lasted only 24-48 h after the end of treatment and was app arently not infection-related. In the remaining nine patients, showing in addition severe neutropenia (neutrophils less than 1.0 x 10(9)/l), fever was related to bacterial infection requiring systemic antibioti cs in all of them and G-CSF in three cases. In conclusion, 2-CdA induc es a very high proportion of complete and long-lasting remissions in p atients with HCL. In a number of cases relapse at bone marrow level ma y not affect peripheral blood values for prolonged time. However, in t hose patients with initial pancytopenia a retreatment with 2-CdA is st ill effective in inducing a durable second CR.