suggests that so-e protective role results frcm the residual tZt- activity. 
Because these patients are relatively stable, they may also be able to survive 
a lag phase after gene therapy. Their relatively large size (25 -30kg) would 
necessitate the production of large amounts of vector, however. In these 
patients who have been treated with essentially supportive therapy only. 
Incomplete ADA-deficiency SCID appears not to be a rapidly fatal disease. 
Thus, the ethical consideration that a fatal underlying disease justifies 
Innovative therapy with a degree of unknown risks and benefits may not apply. 
Finally, the older child can be actively involved in the decisior.-raking 
process. 
5. How will patients be selected If It Is not possible to Include 
all who desire to participate? 
This Is an unlikely problem because of the small number of potential 
patients. The four criteria In descending order of Importance are: 
a) The patients most likely to benefit. 
b) The patients who have the fewest options for alternative therapies. 
c) The patients most likely to be informative to benefit future patients. 
d) The patients whose family Is able to deal satisfactorily with the 
complex medical Issues, media exposure, etc. This criteria, of 
course. Is secondary to the child's ability to benefit medically from 
the procedure. 
D. Informed consent 
Indicate how patients will be Informed about the proposed study and 
how their consent will be solicited. The consent procedure should 
adhere to the requirements of DHHS regulations for the protection of 
human subjects (45 Code of Federal Regulations. Part 46). If the 
study involves pediatric or mentally handicapped patients, describe 
procedures for seeking the permission of parents or guardians and. 
where applicable, the assent of each patient. Areas of special 
concern highlighted below include potential adverse effects, financial 
Recombinant DMA Research, Volume 12 
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