Recombinant DNA Advisory Committee - 03/1-2/93 
assays have been performed, and that Dr. Jack Barber of Viagene, Inc., would provide a 
summary of these data. Dr. Leventhal asked what would be considered as dose-limiting 
toxicity in these patients. Dr. Seigler responded that toxicity is no longer being 
considered as an endpoint. The endpoints will be tumor and CTL responses. In 
addition, if no CTL activity is demonstrated after 10 patients, the study will be 
terminated unless tumor regression is observed. 
Dr. Leventhal asked how toxicity will be monitored and evaluated as a stop criterion. If 
a patient demonstrates fever, chills, and shock, there must be a point at which the 
protocol will be terminated. Dr. Seigler agreed to include the suggested stop criteria in 
the protocol. 
Ms. Meyers asked if the patient would be liable for any costs associated with adverse 
effects associated with an overdose of y-IFN. Dr. Seigler stated that the patient would 
not be financially responsible for the cost of treatments that resulted directly from the 
research. 
Dr. Haselkorn inquired about the responsibilities of the co-investigators and if Dr. 
Seigler is the only investigator who would have contact with the patient. Dr. Jolly of 
Viagene, Inc., responded that he and Dr. Barber will produce the vector at Viagene; Drs. 
Seigler and Darrow will perform the laboratory experiments at Duke University. Dr. 
Seigler will have direct contact with the patients. 
Dr. Barber of Viagene, Inc., addressed the RAC members' questions regarding the 
vector and packaging cell line. The proposed vector and packaging cell have not 
produced helper virus breakout; the breakout that the committee members referred to 
was with another packaging cell line. The proposed system has been extensively 
characterized. All of the RCR testing will be repeated after the master cell bank and 
working cell banks have been established. The testing of the cell banks is currently in 
progress. 
Dr. Post asked further questions regarding the helper virus breakout. If the breakout did 
not occur with the proposed packaging cell line and virus, did it occur with the same 
packaging cell line and another virus? Dr. Barber stated that the breakout occurred with 
a different virus and a different packaging cell line. Dr. Post asked about the difference 
between the two systems. Dr. Barber explained that the gene expression vectors are the 
same; however, everything else is different. The cell line that had the breakout of helper 
virus was the canine fibroblast cell line, CF2. The current packaging cell line is based on 
the canine cell line, D17. The only similarity between the 2 systems is the expression of 
the Moloney structural gene products. Dr. Barber noted that the reason that the RCR 
safety data had not been included in the original submission was that the master and 
working cell banks had not yet been established. 
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