Recombinant DNA Advisory Committee - 12/1-2/94 
development of certain cancers due to a hereditary mutation. Dr. Roth stated that none of the 100 patients 
who were screened had a p53 germ line mutation. 
Dr. Glorioso asked Dr. Roth to compare the adenovirus p53 "bystander" effect to HSV-TK/GCV "bystander" 
effect strategy. Dr. Roth said that the present "bystander" effect is much weaker than the effect observed with 
HSV-TK. Dr. Glorioso asked about the rationale for using p53 instead of the HSV-TK/GCV. 
Dr. Ross stated that any stipulations required for Dr. dayman’s protocol should be applicable to Dr. Roth’s 
previous lung cancer protocol (#9406-079), so that the assays will be conducted for all the studies involving the 
same adeno-p5J construct. Dr. Miller commented that the investigators have provided the best in vitro cell 
culture data for the previous approval. 
As a point of clarification. Dr. Chase said the present stipulation does not include construction of a more risky 
vector with a mutant p53 gene. He said in this case he would support Dr. Haselkorn’s motion. 
Dr. Samulski proposed a friendly amendment to the motion for approval of the protocol. In addition to the 
PCR assays that will be used to show that mutant p53 ’ s are not accumulating in the vector stock, he suggested 
that there be additional assays to characterize the different types of p53 mutations. One could be able to 
determine if there is a correlation between mutants that are stabilized with protein and accumulate versus 
those mutants that produce a truncated or nonfunctional protein. 
Dr. Par km an was concerned about the requirement for inclusion of a biochemical assay for p53 mutations. 
Mutations occur in all genes. Although such a mutation would be expected in some virus stocks, the real 
concern is posed by mutations that have a biological effect. A biological assay for such mutations would be 
preferable to a biochemical assay. Dr. Samulski agreed with Dr. Parkman’s suggestion regarding the biological 
assay. Dr. Roth agreed to discard any virus stock in which a p53 mutation is detected by PCR assay. Dr. 
Glorioso suggested that co-transfection with the ras oncogene could be used to screen for oncogenic p53 
mutants. Dr. dayman said that phenotypically "normal" oral keratinocytes infected by transforming human 
papilloma virus (HPV)-16 and 18 exhibit normal growth when transduced with the wild-type p53 gene. This 
HPV assay could be developed into co-transformation assay for the detection of oncogenic p53 mutants. Dr. 
Haselkorn said such an assay should be an acceptable test for the adenovirus stocks. A subgroup of the RAC 
should review the pertinent data. 
Mr. Capron asked the investigators to use consistent terminology throughout the Informed Consent document, 
and he suggested that the p53 gene be called "normal" instead of "wild-type." 
Dr. Ross asked the investigators to specify post-mortem analyses that will be conducted at autopsy. Dr. 
Clayman agreed to provide a complete description of such a plan. 
Regarding Dr. Roth’s protocol (#9406-079) previously approved by the RAC, Ms. Meyers asked ORDA to 
include a note to the NIH Director conveying the RAC’s concern about potential oncogenic mutations of the 
p53 gene. Dr. Wivel explained that the NIH Director is always informed about contingencies for approval and 
reasons for split votes when considering protocol approval. Dr. Smith said that the NIH Director should be 
informed that the RAC retrospectively recommends amending its approval of Dr. Roth’s protocol (#9406-079) 
contingent on each vector lot should be assayed for the presence of p53 mutants, using the same biological 
assay recommended for Dr. dayman’s study. Dr. DeLeon said that a similar stipulation about autopsy 
analysis should be included for Dr. Roth’s protocol. Mr. Capron said that the FDA should monitor the vector 
lots in regard to the safety concerns raised by the RAC. As a point of clarification. Dr. Haselkorn stated the 
assay for a mutant p53 in the adenovirus vector should be a biological assay such as the proposed HPV system 
and not a PCR biochemical assay. Dr. Par km an confirmed that a biological screening assay will be required. 
Dr. Smith said the RAC is giving the investigators a choice to propose a biological test that is acceptable to a 
RAC subcommittee; if a vector lot is found to contain any mutant p53 , it will be discarded. 
Recombinant DNA Research, Volume 20 
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