Attachment IV - Page 35 
-13- DRAFT 
NOVEMBER 7, 1983 
consisting of a natural substance with a minor modification would require somewhat 
more testing In appropriate animal models. A product radically altered from the 
natural substance would require still more extensive animal tests. Including those 
for carcinogenicity, teratogenicity and effects on fertility. The specific tests 
which might be appropriate are best addressed on a case-by-case basis with the 
appropriate Office. 
VIII. Modified Protein Products 
Using recombinant DNA procedures It may be possible to modify the structure 
of biological proteins to enhance their desired biological properties and/or 
diminish undesirable ones. Any substance which Is not a natural constituent of the 
human body may be antigenic and also may cause unknown and possibly adverse 
biological effects. Whether such a product should be used In humans depends on a 
careful assessment of its new benefits compared to the risks Identifiable during 
Its precllnlcal and clinical evaluation. 
IX. Clinical Trials 
Clinical trials will be necessary for all products derived from recombinant DNA 
technology to evaluate their safety and efficacy. 
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