4 
r*:. Anderson suaqested such tumors would rarely occur in heterozygous indivi- 
duals. Problems are not evident in heterozygous transgenic mice; serious 
problems are evident, however, in homozygous descendants. 
Dr. Walters asked whether investigators would be able to detect an untoward 
event within a few weeks of treatment. Cr. Anderson replied they might. 
Dr. Motulsky said the Working Group on Human Gene Therapy would evaluate the 
possibility of patient injury or spread of recombinant viruses to other people; 
the points to consider document developed by the working group addresses these 
issues. 
Dr. Rich thought at the present time the risks associated with drug therapies 
can be evaluated with greater certainty than the risks associated with human 
gene therapy. 
Mr. Capron said the current druq evaluation process is also inexact. Seme 
druqs which appear to be very safe with no evident adverse effects have caused 
problems in patients several years after administration. Similarly, negative 
side effects of human gene therapy may not be detected for many years; same 
diseases caused by retroviruses have a long incubation period. Ultimately, 
only human studies will demonstrate safety in humans. 
Ms. Witherby said two issues impact ing on an evaluation of the potential for 
neqative effects are: (1) whether test animals have been followed for a 
sufficiently long period of time; and (2) whether the effects of the therapy 
could be controlled or are reversible. 
Report on the November 12, 1985, Meeting of the Recombinant DNA Advisory Corrmittee 
(RAC) Working Group on Viruses 
Dr. Walters then asked Dr. Gottesman, the Chair of the Working Group on 
Viruses, to report on the November 12, 1985, meeting of that working group. 
Dr. Gottesman said the November 12, 1985, meeting was primarily convened: (1) 
to respond to scientific issues originating in a memorandum from the Department 
of Health and Human Services; and (2) to address the impact of recent developments 
in viroloqy on the NIH Guidelines for Research Involving Reccmbinant DNA Molecules. 
Dr. Gottesman said the major issues discussed by the Working Group on Viruses 
were: (1) should RNA derived from recombinant DNA be explicitly covered by the 
NIH Guidelines; (2) should the NIH Guidelines be modified with respect to cloning 
of small fragments of viruses in tissue culture systems; (3) should the NIH 
Guidelines be modified to explicitly refer to experiments involving retreviruses; 
and (4) what safety levels are appropriate for research involving retroviruses? 
Dr. Gottesman said currently the NIH Guidelines only refer to reccmbinant ENA 
and do not refer to RNA derived frem reccmbinant DNA although RNA viruses would 
appear to be covered by case law. A proposal addressing FNA derived from 
reccmbinant DNA was developed by a RAC working group and reviewed by the Working 
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