contaminating materials? What are possible sources of 
contamination? What is the sensitivity of tests used 
to monitor contamination? 
(2) Describe any other material to be used in preparation of 
the material to be administered to the patient. For example, 
if a viral vector is proposed, what is the nature of the 
helper virus or cell line? If carrier particles are to be 
used, what is the nature of these? 
2. Preclinical studies, including risk-assesgnent studies 
Describe the experimental basis (derived f ran tests in cultured 
cells and animals) for claims about the efficacy and safety of the 
proposed system for gene delivery. 
a. Laboratory studies of the delivery system 
(1) What cells are the intended recipients of gene therapy? 
If recipient cells are to be treated hi vitro and returned 
to the patient, how will the cells be characterized before 
and after treatment? What is the theoretical and practical 
basis for assuminq that only the treated cells will act as 
recipients? 
(2) Is the delivery system efficient? What percentage of the 
target cells oontain the added DNA? 
(3) How is the structure of the added DNA sequences monitored 
and what is the sensitivity of the analysis? Is the added 
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