title: Rituximab in relapsed or refractory hairy cell leukemia.
abstract: The purpose of this study was to investigate the efficacy and safety of the monoclonal antibody, rituximab, in relapsed or refractory hairy cell leukemia (HCL). Fifteen patients with relapsed or primary refractory HCL after nucleoside analogs received rituximab 375 mg/m2 weekly for a total of 8 planned doses. An additional 4 doses could be administered to responders who had not achieved complete response (CR). The overall response rate was 80%. Eight patients (53%) achieved CR, 2 (13%) attained CR by hematologic parameters with residual marrow disease (1% to 5% marrow hairy cells), and 2 (13%) had a partial response. Of the 12 responders followed for a median of 32 months (range, 8 to 45+ months), 5 patients (42%) had progression of disease 8, 12, 18, 23, and 39 months from the start of therapy. Three patients failed to respond (after 4, 6, or 8 doses). Reductions in serum interleukin-2 receptor (sIL-2R) levels correlated with response. Toxicity was minimal, and no infectious episodes were observed. Rituximab has significant activity and minimal toxicity in HCL and warrants further study. Rituximab should be explored further in HCL with regard to eradication of minimal residual disease and in combination with nucleoside analogs.
authors.affiliation: Department of Leukemia, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 428, Houston, TX 77030, USA. debthomas@mdanderson.org
authors.forename: Deborah A
authors.initials: DA
authors.lastname: Thomas
authors.forename: Susan
authors.initials: S
authors.lastname: O'Brien
authors.forename: Carlos
authors.initials: C
authors.lastname: Bueso-Ramos
authors.forename: Stefan
authors.initials: S
authors.lastname: Faderl
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Keating
authors.forename: Francis J
authors.initials: FJ
authors.lastname: Giles
authors.forename: Jorge
authors.initials: J
authors.lastname: Cortes
authors.forename: Hagop M
authors.initials: HM
authors.lastname: Kantarjian
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage* / Q000633:toxicity; D058846:Antibodies, Monoclonal, Murine-Derived; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007943:Leukemia, Hairy Cell / Q000150:complications / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D015375:Receptors, Interleukin-2 / Q000097:blood; D012074:Remission Induction; D000069283:Rituximab; D016879:Salvage Therapy; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D058846:Antibodies, Monoclonal, Murine-Derived; D015375:Receptors, Interleukin-2; D000069283:Rituximab