Recombinant DNA Advisory Committee- 9/12-13/94 
vector. 
Regarding the toxicity to the lung of the CF patients, Dr. Crystal said he is starting at a 
low dose of 10 6 pfu and in a smaller volume. The toxicity of the particular patient in the 
other study occurred with 20 ml of vector at high dose. The volume has been reduced to 
100 m 1 per site for a total of 3 distinct sites. The toxicity can be due to spread of liquid to 
the alveolar sac, and the smaller volume of vector inocula will avoid this complication. 
Quantitative PCR will be deleted from the protocol. Regarding the question of subjects 
being immunized by repeat vector administration. Dr. Crystal said that in animal 
experiments as well as in the current human study, no neutralizing antibodies have been 
detected after vector administration. 
As to the concern about bronchial biopsy, Dr. Crystal said there will only be bronchial 
brushing to obtain lung cells rather than biopsy to remove lung tissue. There is no added 
toxicity by using this procedure. 
Regarding the consent process, the patients are allowed 2 weeks to decide about the 
study. 
In terms of glycerol, it is diluted to 3.3%; and no toxicity has been observed at this level. 
As to the bronchial alveolar lavage procedure in the protocol, it has not been applied to 
any patient in the CF protocol. Putting the saline solution to the lung will cause some 
inflammation. The procedure is included in the protocol as a potential means of 
obtaining samples for analyzing cytokines. Dr. Parkman inquired about the toxicity studies 
on animals and requested additional data. 
Mr. Capron asked if the patient population of the present protocol was the same as the 
previous CF study. Dr. Crystal said that the new protocol will recruit patients in the New 
York metropolitan area. As to Mr. Capron’s question about the present study aiming to 
cure CF, Dr. Crystal said that CF is a genetic disease and cannot be cured by the present 
approach. Repeat vector administration is essential to produce long-term relief of the 
lung symptoms. 
Dr. Walters asked for a clarification of the question of vector replication at high dosage. 
Dr. H. Ginsberg said that at 10 10 pfu, he has observed replication of El-deleted 
adenovirus in the cotton rat experiments. It is not a prolonged replication. Dr. Crystal 
emphasized that he has never seen replication of his vector in several monkey and cotton 
rat experiments. Mr. Capron asked if different results were due to different vectors. Dr. 
H. Ginsberg said he is discussing Ela and Elb deleted mutant adenovirus and not the 
vector Dr. Crystal constructed. Dr. Crystal said the clinical grade adenovirus vector 
preparations have to pass a test of less than one replication-competent virus per patient 
dose. With this clinical grade vector, no replication has been observed in animal 
experiments. Mr. Capron inquired if this result is published. Dr. Crystal said it is 
included in the RAC submission. Ms. Meyers expressed her discomfort about the 
contradictory experimental results, especially when the vector is to be used for humans. 
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Recombinant DNA Research, Volume 20 
