SEATTLE--While about 65% of adults with newly diagnosed, acute myelogenous leukemia (AML) are able to achieve complete remission of their disease, this remission is often short-lived when conventional postremission regimens are used. However, new approaches to postremission therapy are proving beneficial to patients, Robert J. Mayer, MD, said at a symposium held in conjunction with the American Society of Hematology's 37th Annual Meeting.
These approaches include high-dose cytarabine(Drug information on cytarabine) (ara-C) as postremission chemotherapy, and cytogenetic analysis to "risk adapt" postremission therapy to an individual patient's cancer karyotype.
Dr. Mayer, professor of medicine, Harvard Medical School, and clinical director, Department of Medicine, Dana-Farber Cancer Institute, presented data from a study conducted by CALGB (Cancer and Leukemia Group B), involving 693 AML patients in complete remission following induction therapy with standard-dose cytarabine and daunorubicin(Drug information on daunorubicin) (Cerubidine).
Patients then were randomized to receive four cycles of cytarabine in one of three dosage schedules: high dose (3g/m², twice daily, on days 1, 3, and 5); intermediate dose (400 mg/m²/day × 5 days); or low dose (100 mg/m²/day × 5 days). This regimen was followed by four cycles of monthly maintenance treatment with cytarabine and daunorubicin, after which all treatment was discontinued.
Four-year disease-free survival rates showed significant advantages for patients who received the high-dose cytara-bine consolidation regimen--43% of the high-dose patients achieved continuous complete remission (CCR) vs 31% and 23% for the intermediate- and low-dose groups, respectively. (Dr. Mayer added that these results were for patients younger than age 60; for those older than 60, the CCR rates were 16% or less for each of the three dosage groups.)
An analysis of pretreatment cytogenetic status showed an even more striking effect of high-dose cytarabine, Dr. Mayer said.
Patients were divided into three prognostic groups according to leukemia karyotype: favorable [t(8;21) or inv(16)]; intermediate [t(15;17) or normal]; and unfavorable (other karyotypes).