ORLANDOImatinib mesylate (STI-571, Gleevec) is showing excellent results in newly diagnosed patients with chronic myelogenous leukemia (CML) in the early chronic phase, scientists reported at the 43rd Annual Meeting of the American Society of Hematology (abstract 577). The response rates reported are significantly higher than those seen in previous trials of interferon regimens.
"Imatinib should now be considered as frontline therapy for all newly diagnosed patients with Ph [Philadelphia chromosome]-positive chronic myelogenous leukemia. It may have the potential to eliminate the disease for long periods, and perhaps permanently," said lead investigator Hagop Kantarjian, MD, professor of medicine and chairman of the leukemia service, M.D. Anderson Cancer Center.
Dr. Kantarjian reviewed the interim results of an ongoing phase II trial in which patients with early Ph+ CML were treated with imatinib at 400 mg daily as initial therapy. Interferon-alfa and cytarabine (ara-C) will be added after 12 months if cytogenetic responses are unsatisfactory.
50 Patients Enrolled
The trial enrolled 50 newly diagnosed patients, with 47 patients currently evaluable after 3 months of treatment and 44 evaluable for efficacy with 6-month follow-up.
After 3 months of treatment, 77% (36 patients) had achieved a complete or major cytogenetic response (Ph less than 35%); after 6 months of treatment, 86% (38 patients) had achieved a complete or major cytogenetic response. The hematologic response rate (normalization of blood counts lasting for at least 4 weeks) was 98% (46 patients) at 4-month follow-up.
Cytogenetic Response Rates