Human Gene Therapy Subcommittee - 11/21-22/91 
administered or contraindicated in these patients. 
Dr. Mclvor summarized by stating that the protocol was well designed, and that the 
introduction of the ablatable function for the selective elimination of cells is an 
innovative concept. There is the potential that the cellular therapy will be effective in 
controlling HIV infection in patients undergoing bone marrow transplantation. He 
suggested a few minor wording changes in the informed consent document and added 
that his primary criticism of the protocol was that the preliminary data supporting the 
feasibility and efficacy of the proposal were not included in the original protocol. 
Review— Dr. Kelley 
Dr. Kelley agreed with Dr. Mclvor that his major concern was the lack of in vivo data 
demonstrating that these T cell clones expressing the HyTK gene are more sensitive to 
ganciclovir than nonselected cells. 
Review~Ms. Meyers 
Ms. Meyers was concerned about the likelihood of success of the proposed study. What 
are the results that have been obtained previously from HIV patients receiving bone 
marrow transplants? Will the virus remaining outside of the bone marrow be affected? 
How long will patient survival be increased as a result of the therapy? Have any animal 
experiments been performed? 
Ms. Meyers expressed concerns regarding the informed consent document. She 
suggested that the clause, "Although we expect it to benefit your condition," should be 
changed to read, "We hope this is going to benefit your condition." The document 
describes the risk of death as very remote and added that this statement is not accurate 
since risks associated with bone marrow transplant alone in these patients are high. Will 
women be included in this study in addition to men? 
Other Comments 
Dr. Kelley stated that since the gene marking portion is a minor addition to an already 
existing bone marrow transplantation protocol, perhaps the subcommittee should only 
comment on the gene transfer aspects of the protocol. Mr. Capron asked the 
investigators to discuss other review processes that the protocol has undergone. Ms. 
Meyers added that if the risk of the bone marrow transplant is high, then results may 
never be obtained from the gene marking portion of the experiment. Dr. Miller agreed 
that the HGTS must consider the risk-benefit ratio to these patients and whether the 
procedure is worth performing to justify the risk of the gene modification. If patients are 
not likely to survive long enough to interpret the experiment, then that is an important 
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Recombinant DNA Research, Volume 15 
