title: Long-term follow-up of patients with hairy cell leukemia after cladribine treatment.
abstract: Hairy cell leukemia is a chronic B-cell disorder that follows an indolent, but progressive course. Cladribine (2-chlorodeoxyadenosine) induces complete remissions in the majority of patients after a single course. We report the long-term outcomes, including response rates and their duration; time-to-treatment failure (TTF) rates; retreatment results; toxicities; and survival rates of patients treated at Scripps Clinic (La Jolla, CA). A total of 358 patients with hairy cell leukemia were treated with cladribine at 0.087 or 0.1 mg/kg body weight per day by continuous intravenous infusion for 7 days. The expected number of second neoplasms was based on the National Cancer Institute's Surveillance Epidemiology and End Results data. Of 349 evaluable patients, 319 (91%) achieved an initial complete response and 22 (7%) a partial response with an overall median duration of response follow-up of 52 months. Ninety patients (26%) had relapsed at a median of 29 months. The TTF rate for all 341 responders was 19% at 48 months, 16% for complete responders, and 54% for partial responders. Of 53 evaluable patients treated with second courses of cladribine at first relapse, 33 (62%) achieved complete responses and 14 (26%) partial responses. Twenty-seven patients (8%) developed second neoplasms (only 1 hematopoietic) with an observed-to-expected ratio of 1.88 (95% confidence interval, 1.24 to 2.74). The overall survival rate was 96% at 48 months. Single courses of cladribine induced long-lasting complete responses in the vast majority of patients. Relapse rates for complete responders were low. Patients who relapse can be successfully retreated with cladribine. Cladribine has high efficacy and a favorable acute and long-term toxicity profile when administered to patients with hairy cell leukemia.
authors.affiliation: Division of Hematology/Oncology, Ida M. and Cecil H. Green Cancer Center, Scripps Clinic, La Jolla, CA; The Scripps Research Institute, La Jolla, CA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Saven
authors.forename: C
authors.initials: C
authors.lastname: Burian
authors.forename: J A
authors.initials: JA
authors.lastname: Koziol
authors.forename: L D
authors.initials: LD
authors.lastname: Piro
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D017338:Cladribine / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007372:Interferons / Q000627:therapeutic use; D007943:Leukemia, Hairy Cell / Q000150:complications / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D016609:Neoplasms, Second Primary / Q000139:chemically induced; D015649:Pentostatin / Q000627:therapeutic use; D012074:Remission Induction; D013156:Splenectomy; D016019:Survival Analysis; D017211:Treatment Failure
chemical_list: D000970:Antineoplastic Agents; D015649:Pentostatin; D017338:Cladribine; D007372:Interferons