Homoharringtonine and Low-Dose Cytarabine in the Management of Late Chronic-Phase Chronic Myelogenous Leukemia

Abstract

PURPOSE: : To evaluate the efficacy andtoxicity profiles of a combination regimen of homoharringtonine (HHT)and low-dose cytarabine (ara-C) in patients with Philadelphiachromosome (Ph)–positive chronic myelogenous leukemia (CML) whohad experienced treatment failure with interferon alfa (IFNα)therapy. PATIENTS AND METHODS: One hundred five patients were treated: 100 in chronicphase (15 with cytogenetic clonal evolution) and five in acceleratedphase. Their median age was 52 years; all had been treatedunsuccessfully with IFNα; 94% were in late chronic phase; 43% hadbeen exposed to ara-C and 11% had been exposed to HHT. Patientsreceived HHT 2.5 mg/m2 by continuousinfusion daily for 5 days and ara-C 15mg/m2 daily in two subcutaneous injectionsfor 5 days every 4 weeks. The outcome of the 100 patients in chronicphase was compared with a previous study group of 73 patients treatedwith HHT alone. RESULTS: Overall, the complete hematologic response (CHR) rate in chronic phasewas 72%; the cytogenetic response rate was 32% (major response, 15%;complete response, 5%). Toxicities were acceptable, mostly related tomoderate diarrhea (3%), headaches (3%), cardiovascular events (3%),and myelosuppression-associated complications (3% to 14%). With amedian follow-up period of 25 months, the estimated 4-year survivalrate was 55%. Response rates were identical with HHT plus ara-C versusHHT alone, but the survival was significantly longer with thecombination after accounting for differences in the study groups andby multivariate analysis. CONCLUSION: The combination regimen of HHT and ara-C is effective andsafe in patients with CML who have experienced treatment failure withIFNα and needs to be investigated together with IFNα as partof front-line CML therapy. The addition of ara-C did not improve theresponse rates but may have improved survival, perhaps throughsuppression of clones related to diseasetransformation.