Recombinant DNA Advisory Committee - 09/9-10/93 
Responding to the question of EL-2 production. Dr. Podack stated that in one human cell 
line studied, the level of production was between the range of 6,000 and 9,600 units of 
II^-2/ml/lO 6 cells/24 hours; and in another cell line, the level of expression was between 
4,000 and 5,000 units of 11^2/ml/lO 6 cells/24 hours. These levels are at least one order 
of magnitude higher than the same cell lines transfected with retrovirus vectors. After 
irradiation, the transfected cells continued to produce the same level of H^2 for 2 days; 
however, H^-2 expression declined over the next 6 days. Regarding the episomal status 
of the BPV vector, he explained that the vector is maintained episomally at 
approximately 16 copies per cell in human HeLa cells. Data derived from murine 
experiments suggest that there is a strong correlation between copy number and the 
levels of EL-2 expression. 
Dr. Podack stated that Dr. Savaraj, a co-investigator on this protocol, has established cell 
lines from fresh tumor specimens at approximately a 70% success rate. Dr. Podack 
explained that most of the preclinical data was obtained using a cell line that has been 
grown for a relatively short term in vitro. This cell line was established in approximately 
2 months, and aliquots of these cells were cryopreserved. All experiments were 
performed using cells grown from the cryopreserved stock. Dr. Podack stated that more 
comprehensive data would be obtained from a broader range of cell lines established 
from fresh tumors. 
Dr. Cassileth responded to questions relating to the clinical aspects of the protocol. The 
financial responsibility for costs associated with the treatment of adverse effects arising 
from the research study will be the responsibility of the patient, third party payers, or 
both. He explained that his local Institutional Review Board (IRB) requires this 
statement in the Informed Consent document. He said he is of the opinion that 
compensation for research related injury is an issue that should be addressed in a 
broader sense. 
In regard to their success rate for establishing fresh tumor cell lines, Dr. Cassileth stated 
that they have demonstrated a success rate of between 70 and 80%. Overall, 
approximately 30% of the patients initially entered onto the protocol will be eligible to 
receive the transfected cells due to the exclusion of some patients based on entrance 
criteria. 
Mr. Capron remarked that the terms "therapy" and "treatment" in the Informed Consent 
document are inappropriate for a Phase I study. Dr. Cassileth agreed to revise this 
inappropriate language. 
Drs. Parkman and Post requested that a minimum level of lb-2 production should be 
demonstrated prior to reimplantation of the transfected cells into patients. Dr. Miller 
suggested that 10 units of IL-2/ml/lO 6 cells/24 hours is an acceptable minimal level. Dr. 
Podack stated that 50 units of IL-2/ml/lO 6 cells/24 hours is an acceptable minimal level 
of IE^-2 expression. 
In regard to Dr. Haselkom's concern about whether BPV is maintained episomally in 
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