Autologous Bone Marrow Transplantation - Blog Science Connections

50 Panel Discussion: Session IA
the intensive chemotherapy at the time of marrow harvest. The latter possibility
is not likely because acute lymphocytic leukemia (ALL) treatment is probably
and quite similarly intensive in this disease and autologous bone marrow
transplantation (ABMT) is not associated with delayed recovery.
DR. F. BABAPULLE: Dr. Lowenberg, your patients experienced prolonged
pancytopenia following the autograft and you showed a correlation between
this phenomenon and granulocyte-macrophage colony-forming unit (CFCI-GM)
numbers. Do you think you could have circumvented this problem by actually
increasing the cell dose or giving them a supplementary autograft, maybe 14
days after the first?
DR. LOWENBERG: At this time, we cannot solve that question. We gave all
the cells we harvested immediately after finishing the conditioning regimen, so
we had no additional cells left for a second transplant.
DR. C. AUGUST: This may be a naive question and I will ask it to whomever
wants to answer it. In the last 3-5 years there has been an extraordinary
improvement in the results of this endeavor of using both purged and unpurged
marrows. I would like to ask to what do you attribute this?
DR. DlCKE: The question is not naive. Let me try to answer it. First, ABMT
is done in an early stage of the disease, so that drug resistance will be minimal.
Second, the time of marrow harvest, after relatively aggressive chemotherapy,
may minimize the presence of leukemic cells. Third, the improved results might
be due to patient selection. Randomized studies will answer this.
Dr. Mandelli, what was the mortality immediately after transplantation in
your first-remission studies?
DR. F. MANDELLI: Only one death of pulmonary embolism at 21 days after
bone marrow infusion.
DR. BURNETT: Dr. Mandelli, how many patients do you know you lost
between achieving remission and doing the autograft who are not actually
postautograft patients?
DR. MANDELLI: Our program was instituted 2 years ago and I think that the
loss of patients was almost between 20% and 25% before bone marrow
transplantation.
DR. DICKE: Are there any questions for Dr. Gorin?
DR. BURNETT: Claude (Dr. Gorin), we've done several in vitro studies on
purging and have not been able to demonstrate that cells prepared as a
mononuclear concentrate from bulk marrow have a reproducible doseresponse
curve. We do two harvests, and we always store one as a back-up. We
have not had the same dose response on a full mononuclear bulk-prepared
marrow as we had the second time. My questions are: Do you know whether it is
fair to make your assumption on an aspirate rather than on your final product?
Was your actual kill, the second time, what you anticipated?