VI Autologous Bone Marrow Transplantation.pdf - Blog Science ...

AUTOLOGOUS BONE MARROW TRANSPLANTATION FOR ACUTE
MYELOID LEUKEMIA
Armand Keating, MD, FRCPC
University of Toronto Autologous Bone Marrow Transplant Program, The
Toronto Hospital, Toronto, Ontario, Canada
Results of numerous single arm studies of intensive therapy and ABMT for
AML suggest an apparent advantage over optimal conventional chemotherapy.
A recent unpublished update of 8 trials of ABMT for AML in first remission
(CR-1) involving a total of 425 patients indicates a disease-free survival (DFS)
range of 48-58 percent at a median follow-up ranging from 18 to 96 months.
Also, 5 trials contributing a total of 209 patients with AML CR-2 at a minimum
median follow-up of 34 months after ABMT had DFS from 14 to 53 percent.
Although these data are gratifying, and are suggestive of the superiority of
ABMT, several confounding patient-, disease- and treatment-related variables
make comparisons with cohorts treated with chemotherapy alone, problematic.
Such variables include age, white blood cell count at diagnosis, cytogenetic abnormalities
and FAB type. A major problem in analyzing transplant data relates
to the issue of time censoring of patients who receive transplants. Patients who
achieve remission and relapse before a scheduled transplant are invariably excluded
from the transplant cohort but are frequently included if assigned to a
chemotherapy group. This proportion may be as high as 20 percent.
In view of the issues raised above, it was particularly appropriate to focus
on current prospective trials of ABMT for AML in the leukemia session of the
Symposium.
Four trials were reviewed: the U.K. MRC10 trial, the EORTC-GGvIEMA trial,
the GOELAM trial and the BGMT study.
A. Burnett reported that the MRC10 trial has accrued over 1200 subjects
with an overall CR rate of 82 percent (children included). Of interest, actuarial
relapse was below 10 percent within the first 6 months after achieving CR. Over
90 patients have been randomized to the ABMT arm and analysis will be based
on intention to treat. The study will be analyzed in late 1994 and should provide
a comparison of DFS and relapse rate for patients undergoing allo-transplants,
ABMT or chemotherapy. Results of this large and important study will be
awaited with interest.
R. Zittoun provided a preliminary analysis of the EORTC-GIMEMA Study
(AML 8A) comparing allo-BMT, ABMT and intensive consolidation for AML
CR-1. A total of 988 subjects were registered and 581 (67 percent) achieved CR.
119 underwent allo-BMT while 239 were randomized to ABMT (119) or intensive
consolidation (120). Actuarial DFS at 3 years favors ABMT, although results
are not statistically significant: ABMT, 50+11.2 percent vs 31+1.4 percent for intensive
consolidation. Results with allo-BMT were not different with DFS of
51+11.4 percent. Overall survival is similar in all groups.
SIXTH INTERNATIONAL SYMPOSIUM ON AUTOLOGOUS BONE MARROW TRANSPLANTATION 247