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

sible in an environment where access to a transplant unit usually involved some
delay. In the event, 9 patients who relapsed were autografted in relapse - only
one survives, with relatively short follow-up.
One of the early concerns was whether re-induction would be more difficult
given that the first line treatment was much more intensive than in previous trials.
Our previous trials had found a dominant effect of the length of first CR on
the chances of entering remission. In fact this pattern of reinduction in AMLIO
has been at least as good (duration of CR 12mo 78%).
Within these subdivisions DAT or ADE was at least as successful as alternative,
usually more aggressive or exotic, combinations (table 1). It should be pointed
out that these data are not randomized and there may well be selection biases in
what re-induction schedule was given.
Of 170 patients who relapsed, of whom the statistical center is aware, 48
achieved a second CR. It should be noted that not all patients had an attempt at
reinduction. Of the 48 CR2 patients, only 18 so far have received an auto BMT
with a survival of around 30% on relatively short follow-up. This mimics the
single center and registry experience. However, this was a selected patient
group because 30 eligible patients did not receive the second CR autograft because
of relapse (n=4) or early death (n=16) or were not considered fit. Ten of
this group remain in CCR. This preliminary experience suggests that only a
small number of patients who relapse in practice get to autograft. It therefore
remains to be seen whether the adoption of a delayed transplant strategy will
make any significant impact on survival in AML.
OVERALL TRIAL OUTCOME
No analysis relating to the major trial questions has so far been undertaken
but is intended by late 1994. However, entrants to this trial are enjoying a significantly
better outlook than MRC Trial entrants in the previous decade, even
when the influence of the pediatric sub-group is allowed for, Such benefits over
AML9 are apparent even if the transplanted groups are excluded from both trials.
This suggests that the recipients of chemotherapy alone are enjoying an important
benefit but until complete analysis is performed we are not in a position
to know whether or not any of the BMT options bring additional benefit on top
of that.
Preliminary inspection has suggested certain subgroups of patients who are
enjoying a better than average survival. These include those with an 8:21 or
15:17 translocation and patients who enter remission with the first course.
Whether these are the same patient group is not yet clear. Nor does this infer
that they do or do not derive benefit from a transplant option. But these could
clearly be used as landmarks for more individually oriented risk-directed
therapy in the future. Interestingly, the experience of the EBMT Group suggests
that purging the autograft will not benefit patients who enter remission quickly,
presumably because they already are a good risk group. Our 4 year accrual of
1150 patients has produced 950 patients in remission, of whom a subset of
around 250 fail to enter remission promptly, and might, as one option for the
future, benefit from a purging approach. This is approximately the patient number
which would need to be recruited to a randomization to confirm, with sufficient
statistical confidence, the apparent benefit of purging in this subgroup.
SIXTH INTERNATIONAL SYMPOSIUM ON AUTOLOGOUS BONE MARROW TRANSPLANTATION 3