ORLANDOProlonged 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.
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.