Autologous Bone Marrow Transplantation - Blog Science Connections

64 ABMT in Acute Nonlymphocytic Leukemia
persistent thrombocytopenia (platelet counts, 30-35 x 10 9 /l) 249 days after
transplantation. In the remaining 25 patients, the median time to attain a platelet
count greater than 50 x 10 9 /1 was 63 days (range, 23-330 days) after
autologous marrow infusion.
Leukemic Relapses and Disease-free Survival
Of the 28 évaluable patients, leukemic relapses were observed in 12 of 22
patients undergoing ABMT in second remission and in three of six patients
undergoing transplantation in third remission. The median time until relapse
was 176 days (range, 60-321 days) after autologous marrow infusion, for an
actuarial relapse rate of 53%. All relapses were hematologic in nature, and no
episodes of nervous system or gonadal involvement were apparent at the time
of relapse. The relapses occurred in nine patients with FAB morphologic class
ML two in class M 2
, one in class M 3
, and three in class M 4
. There was no
significant difference in length of first remission between those who relapsed
(median duration, 13 months; range, 3-53 months) and those who remained
free of disease (median duration of first remission, 19 months; range, 2-41
months). The intervals between attainment of remission and time of marrow
transplantation were similar in both groups. Attempts at reinduction therapy
were successful in 5 patients; the other 10 have died with leukemia in relapse or
of complications of its treatment. Thirteen patients remain in unmaintained
second (10 patients) or third (3 patients) remission at a median of 572 days
(range, 228-1,869 days) after transplantation with 4-HC-treated autologous
marrow. In 7 of these 13 patients, the duration of remission after transplantation
exceeds the duration of first remission; in contrast, only 1 of the 15 patients who
relapsed had a posttransplantation remission that exceeded the duration of first
remission. Actuarial survival analysis in these patients indicates an overall
survival of 41% and an event-free survival of 31% (Fig 1).
DISCUSSION
Intensive chemoradiotherapy and infusion of histocompatible marrow
from a normal donor may be curative in many patients with acute leukemia
whose chances of disease-free survival are negligible with current conventional
chemotherapy. Transplantation with autologous marrow may provide some
advantages over the use of allogeneic marrow. For example, the risks of acute
graft-versus-host disease, a major cause of morbidity and mortality after
allogeneic BMT, are greatly minimized with autologous marrow. However,
experiences with syngeneic BMT for acute leukemia have demonstrated a high
(50-60%) relapse rate (17), suggesting that the antileukemic effects observed
after allogeneic transplantation are attributable, at least in part, to graft-versusleukemia
effects ( 18,19). One might therefore expect that ABMT would at best
provide antileukemic effects that are similar to those observed after syngeneic
transplantation (i.e., a higher incidence of leukemic relapses but a lower