ORLANDO—Prolonged maintenance treatment improves long-term outcome in acute myeloid leukemia (AML) more than intensive consolidation, even in those patients with poor prognosis, according to a study reported by Thomas Buchner, MD, professor of internal medicine, hematology and oncology at the University of Muenster in Germany (ASCO abstract 1046).
"Maintenance produced significant benefit in relapse-free survival and higher cure rate than seen with first-line therapy alone," he said. The benefits of prolonged maintenance in the poor prognostic subgroup are considered especially encouraging, because this subgroup represents more than half of the patients.
Although recent studies have enhanced understanding of prognostic factors and subgroups in AML, data concerning specific effects of particular treatments in each subgroup are still lacking. Because 18% of all patients in the first Acute Myeloid Leukemia Cooperative Group (AMLCG) study in 1981 were still alive and in remission after 10 years, investigators began to consider the role of prolonged maintenance.
Groups Well-Balanced
In this large randomized trial, 837 patients received treatment with either TAD (thioguanine/cytarabine [Ara-C]/daunorubicin)-HAM (high-dose Ara-C/mitoxantrone [Novantrone] induction, TAD consolidation, and S-HAM (sequential HAM) second consolidation, or with TAD-HAM-TAD and monthly reduced TAD maintenance for 3 years.
Average age was 55 years; age range was 16 to 82 years; and 36% of patients were age 60 or older. In the maintenance and S-HAM arms, groups were well balanced for age, LDH, cytogenetic groups, and day 16 blasts. In addition, members of the two groups had nearly identical response to induction, with complete remission in 69% and 70%, respectively.
In the maintenance arm, median relapse-free survival (RFS) was 19 months and 5-year survival was 31%. In the S-HAM arm, RFS was 12 months and 5-year survival was 24% (P = .014). "This difference is not an effect of an inadequate intensity of the S-HAM regimen, as the S-HAM regimen was highly myelotoxic, causing 6 weeks of severe neutropenia and thrombocytopenia," Dr. Buchner said.
