Recombinant DMA Advisory Committee - 12/3-4/92 
setting. Dr. Kahn stated that the FDA has been made aware of data indicating that co- 
cultivation of cells detects RCR, whereas direct testing of the supernatant does not 
detect RCR. Dr. Anderson inquired about the source of this data. Dr. Kahn said that 
she could not discuss the co-cultivation data. Dr. Kahn added that Dr. Janet Hartley has 
data in her notebook that she is willing to share if necessary. Dr. Anderson was 
concerned that the FDA is proposing a regulatory assay based on preliminary data that is 
still in someone's notebook. Dr. D. Miller said that the RAC should have access to this 
data, because it is central to this discussion. 
Dr. Kurt Gunter of the FDA responded that the FDA is currently in the process of 
conducting the suggested reconstruction experiments. These experiments will be 
compared to other testing methods and validated. Once the FDA has solid information 
(solid data on the relative sensitivities and the relative usefulness of co-cultivation), a 
rational decision will be made about the preferable method of testing. However, it is 
reasonable that co-cultivation assays should be performed if there is no undue burden 
placed on the investigator. Dr. Gunter explained that the FDA recommendations 
distributed by Dr. Kahn are for discussion purposes. These are procedures that are 
being considered by the FDA. 
Dr. Anderson stated that it is very important that the RAC continue to work with the 
FDA on this issue. However, he expressed concern about the FDA's proposed 
recommendations. Although the FDA has proposed to perform RCR testing in a 
responsible manner, Dr. Anderson said that he would like to offer several counter- 
suggestions. The margin of safety imposed by present assays must be considered. Is it 
necessary to establish more sensitive assays? There is no question that sensitive assays 
must exist, and that investigators must be conscientious. There is no evidence, however, 
that the present assays need to be improved. In response to the FDA's comments 
regarding the preliminary nature of these proposals, Dr. Anderson reminded the RAC 
that the FDA had proposed a clinical hold on all gene therapy protocols several months 
ago until new standards could be developed. Subsequently, the FDA withdrew the 
proposed clinical hold. Although the FDA has not delayed any human gene therapy 
protocols, the threat still remains. 
Dr. Anderson explained that the assays proposed by the FDA are reasonable assays. In 
fact, they have included every assay that could possibly be conceived to improve the level 
of sensitivity. However, these are not regulatory assays. The proposed testing will cost 
investigators hundreds of thousands of dollars and an enormous amount of time. The 
FDA could bring the entire field of biotechnology to its knees, and then the U.S. might 
have to buy its recombinant products from another country such as Japan. It is 
imperative that the RAC and FDA ask the fundamental question. Do we need new, 
more sensitive assays? Dr. Anderson stated that he is of the opinion that new, more 
sensitive assays are not necessary. 
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Recombinant DNA Research, Volume 16 
