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 (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 (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
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).