Recombinant DMA Advisory Committee - 5/30-31/91 
to rule out the possibility of having no RNA in a sample. Dr. Deisseroth said that this was 
a good suggestion and in fact is part of the algorithm for PCR analysis. 
Dr. Carmen said he had some minor changes in wording in the consent document that he felt 
were also called for which had not been noted in Dr. Walters' summary. He said the changes 
were under "Description of Research," paragraph 3, beginning on line 11, to strike out the 
term "DNA molecule" and insert "a bacterial marker gene" in its place. Then change the 
sentence in the same paragraph that begins with "Thirty percent of your stored cells..." to read: 
"Thirty percent of your stored cells will be mixed with a specially engineered 
mouse virus which cannot cause an infection in the body. This virus will mark 
your cells with a bacterial gene that makes it possible to find these cells." 
Dr. Deisseroth agreed to make these changes in the informed consent document. 
Dr. Mclvor said he was not in agreement that a negative result would mean that the relapse 
was caused by residual systemic leukemic cells. He noted that if 10% of the cells were 
marked and only 1 cell contributed to the regeneration of a tumor and it all came from the 
marrow, there was a 90% probability that there will not be any marked cells in the population 
of relapsed tumor cells. Dr. Mclvor asked that the informed consent document state "It is 
also possible that no information will be gained from the gene marking study." Dr. Deisseroth 
agreed to include this in the consent form. 
Dr. McGarrity asked Dr. Walters to compile a master copy of the changes which were made 
to the informed consent document and then asked for a motion on the protocol. 
Dr. Mclvor moved that the protocol be approved contingent upon the changes in the informed 
consent document and with the suggestion that a large-scale dry run be attempted before the 
actual experiment is performed in up to 10 patients. He asked for clarification on the early 
stopping rule to be employed in the protocol. Dr. Deisseroth said that the usual rule was in 
therapeutic protocols to stop if there are 3 treatment deaths. In this case, if there were 3 
failures to engraft the study would be stopped. He noted that the investigators would have 
back-up unmarked marrow to cover this contingency and thereby not subject the patients to 
an adverse outcome in terms of the viral marking on the viability of the marrow. 
Dr. R. Murray seconded Dr. Mclvor's motion. 
Dr. Leventhal asked if Dr. Deisseroth was going to provide a full revised protocol with a road 
map stating when each step would be done. He said he would send that in immediately. 
There being no further discussion. Dr. McGarrity put the motion to a vote. The motion 
passed by a vote of 19 in favor, none opposed and no abstentions. 
Dr. McGarrity then called on Dr. Brenner to present the next agenda item. 
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Recombinant DNA Research, Volume 14 
