Risk and early cytogenetic response to imatinib and interferon in chronic myeloid leukemia.

BACKGROUND AND OBJECTIVES We compared the early cytogenetic response (CgR) to a combination of imatinib mesylate (Glivec, Novartis Pharma, Basel, Switzerland) and a pegylated form of human recombinant interferon-alpha2b (pegIFN-alpha2b, PegIntron, Schering Plough, Kenilworth, New Jersey, USA) with the relative risk, either according to Sokal's or Euro scoring systems. DESIGN AND METHODS Seventy-seven patients with early chronic phase, previously untreated, Ph-positive chronic myeloid leukemia (CML) received a combination of imatinib mesylate (400 mg/day) and pegIFN-alpha2b (3 consecutive cohorts treated with 50, 100 or 150 mg/weekly). Fifty-seven patients have completed the first 6 months of treatment and are evaluable for CgR. RESULTS After 6 months of treatment, the overall major CgR rate was 89% and 90% in low risk patients (Sokal's and Euro, respectively), 76 and 59% in intermediate risk and 23% and 17% in high risk patients. These differences were significant (p=0.0001 for Sokal and 0.001 for e). INTERPRETATION AND CONCLUSIONS For the first time, these data suggest that the early CgR rate to a imatinib mesylate-based regimen is significantly risk-related.