Human Gene Therapy Subcommittee - 11/30/90 
versus those found in adjacent skin could answer this question. Dr. Parkman said 
that in order to prove this point, there would have to be at least a three log 
difference in the frequency of cells in normal tissue from tumor, and he questioned 
whether this large difference could be anticipated. 
Dr. Lotze said that the NIH group had noted a more than one log difference using 
semiquantitative PCR. Dr. Parkman asked to see data on this finding. Dr. 
Anderson said that such specific data did not exist because of a lack of appropriate 
patients and the difficulty of extracting skin for PCR analysis. The data to which Dr. 
Lotze is referring comes from indium labeled cells in which a two log difference was 
noted between normal adjacent skin and tumor. Dr. Kelley agreed with Dr. 
Parkman that this difference was a critical variable for future experiments. 
However, there is a concern that the correct studies are being performed evaluating 
homing of the TIL. The investigators have underestimated the importance of this 
issue to the future of human gene therapy research. Dr. Lotze said that he 
understood the importance of this point. However, it is critical to have a complete 
understanding of how the system works and how cells persist. 
Dr. R. Murray drew a corollary to a study section reviewing two protocols dealing 
with similar problems. Just because both grants address similar problems, does not 
mean both will be funded or will receive different priority scores. There is no 
problem with allowing different institutions to conduct protocols that either replicate 
or carry out similar types of studies. 
Dr. Parkman said the protocol did not state that normal skin would be biopsied as a 
part of the protocol, and it is not mentioned in the informed consent document. Yet 
under the parameters to be measured, it states that tumor biopsies would be taken 
"if feasible." Dr. Lotze said that this point would be added to the protocol if indeed 
it was not within it already. 
Dr. Kelley said the reason why this protocol was a reasonable gene transfer 
experiment was to answer homing questions, and it is important to see evidence that 
this question will be answered. 
Dr. Epstein made a motion that the HGTS give the protocol provisional approval 
contingent upon the investigator bringing to the RAC an amended protocol defining 
how the homing experiments will be conducted and an amended consent form. 
Dr. Erickson asked if it would require an explanation of how the homing 
experiments will be conducted or evidence that the experiment can be performed? 
Dr. Epstein said he would accept clear evidence of the likelihood of getting an 
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