Recombinant DNA Advisory Committee - 06/1-2/92 
Ms. Meyers commented that sections of the informed consent document were written in 
language that is considered too technical to be understood by a layperson. Also, a 
request for autopsy was omitted from the document. Dr. Deisseroth needs to explain the 
differences between this protocol and his previously approved protocol. Will any new 
information be derived from this study? 
Dr. Geiduschek noted that a similar CML protocol, submitted by Dr. Cynthia Dunbar, is 
on the agenda for the RAC meeting tomorrow. Since some of the information derived 
from these two protocols is duplicate in some aspects, he suggested that the RAC 
consider the number of patients being entered into each protocol. There are also 
dissimilarities between Drs. Deisseroth and Dunbar's CML protocols. 
Dr. Geiduschek stated that his major concern regarded the safety issues surrounding the 
administration of chemotherapy/radiation treatments that could be fatal to a small 
percentage of these patients. If the only benefit of this protocol is gene marking, than 
the risks associated with the treatment should be a major consideration. 
Dr. Geiduschek noted a significant difference between Drs. Deisseroth and Dr. Dunbar's 
protocol. Dr. Deisseroth proposes to reconstitute the patients entirely with CD34( + ) 
selected cells, and Dr. Dunbar proposes to reconstitute with a combination of CD34( + ) 
marked cells and unselected bone marrow that has been cryopreserved and stored. Dr. 
Deisseroth needs to compare these two strategies. 
Dr. Geiduschek stated that Dr. Dunbar has presented in vivo monkey data demonstrating 
that these animals were infected with supernatants that were contaminated with 
replication competent virus. In turn, these monkeys developed T-cell 
leukemia/lymphoma. The investigators stated that safety tests performed on 
approximately 200 supernatants containing safety modified vectors at GTI indicate that 
no replication competent virus is present. Dr. Deisseroth needs to expand on this data. 
What is the upper limit of contamination with statistical extrapolation? 
Dr. Leventhal asked the investigators to explain why they are choosing to use purged 
bone marrow for transplantation versus unpurged? Will the use of purged marrow affect 
decisions regarding CD34( + ) selection and the risk/benefit considerations. 
Presentation-Dr. Deisseroth 
Dr. Murray called on Dr. Deisseroth to respond to the questions presented by the 
primary and secondary reviewers as well as the other committee members. Dr. 
Deisseroth stated the difference between this proposed protocol and his previously 
approved protocols. Dr. Deisseroth said that this protocol is designed to treat patients 
with autologous cells that are in the last phase, the accelerated or blast crisis phase, of 
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