Recombinant DNA Advisory Committee - 06/1-2/92 
contribution of the two sources of relapse. 
Mr. Capron stated that it is extremely important that investigators planning to submit 
protocols to the RAC for review should not underestimate the importance of a well 
designed and thought out informed consent document. In addition, principal 
investigators should detail the process by which these patients will receive this 
information. Dr. Deisseroth stated that he appreciated the RAC's questions and 
comments concerning the informed consent process, and that it is important for stringent 
dialogue to transpire between people who represent all aspects of society. It is 
important to ensure that these gene therapy programs are launched in a manner that is 
evaluable as well as in the best interest of society. 
Dr. Parkman stated that some of the controversy surrounding the contents of the 
informed consent document stems from the fusion of the Human Gene Therapy 
Subcommittee (HGTS) with the parent committee, the RAC. The informed consent 
document provided by Dr. Deisseroth that has elicited this controversy today is a 
therapeutic protocol and is separate from the gene marking document. The RAC should 
focus on the gene therapy aspects similar to the HGTS. 
Dr. D. Miller commented on the issue of helper virus contamination. Although it is 
difficult to detect helper virus in the small volumes of supernatant being tested, the RAC 
should be reassured by the fact that Dr. Brenner has been able to culture the vector 
producing cells for many months without detecting any viral contamination. If there 
were undetectable levels of virus initially, there would be enormous amounts of virus 
present following several weeks in culture. Dr. Brenner's estimate of 15 helper virus 
particles per liter is an overestimate. Dr. McGarrity commented that supernatant 
samples for helper virus assays are taken from pooled production runs, not one ampule 
or one flask. 
Dr. Walters asked if the patients will be subjected to more than one procedure for 
obtaining bone marrow? Dr. Deisseroth responded that twice the necessary quantity of 
peripheral blood and bone marrow cells are stored for transplantation. Storing a large 
number of cells ensures that cells will be available for a second transplantation 
procedure should the first engraftment fail. 
Dr. Leventhal asked if patients would be subjected to additional procedures beyond 
those that would be required for bone marrow transplantation, e.g., more needle sticks. 
Dr. Deisseroth replied that the gene marking patients will not be subjected to any 
procedures except for sampling in order to monitor the gene markers. These sampling 
procedures are explained in detail in the informed consent document. 
Dr. Carmen moved to call the question. The motion was seconded by Dr. D. Miller. By 
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Recombinant DNA Research, Volume 15 
