June 1, 1990, Human Gene Therapy Subcommittee Minutes 
factors that are familiar to the subcommittee. 
In response to the question about amount of blood to be drawn, Dr. Blaese said that 
apheresis will take place once a month, drawing the amount of seven cc's per kilogram. 
Only lymphocytes will be removed, and the red cells will be returned to the patient. 
This amounts to 10 percent of blood volume being sampled once a month as defined in 
the protocol. Dr. Leventhal said the Red Cross advises that if ten percent of blood 
volume is sampled every six weeks, rather than monthly, anemia will be produced after 
several months. Dr. Blaese said that if the patients require an iron supplement to 
counter the anemia, this will be done. 
As to the issue of intraperitoneal infusion versus intravenous infusion. Dr. Blaese said 
that his feeling was that in some animal studies it has been able to show that peripheral 
lymphocytes injected intraperitoneally could be found up to 539 days in a frequency of 
between 1 in 100,000 and 1 in 10 million in peripheral blood by using PCR techniques. 
One of the reasons for considering the IP route of administration is that the vast 
majority of TILs migrate into the liver and lungs within 24 hours of infusion and are then 
released. The feeling was that IP administration would avoid that initial clearance, 
giving the cells a chance to glycosylate their surface membrane proteins in the 
peritoneum before being exposed to the galactose lectin receptor found in Kupffer cells 
in the liver, which prior to glycosylation, pull the cells out of circulation. There is no 
quantitative data, but this seems a reasonable alternative if intravenous administration is 
not successful. 
Dr. Blaese said that as far as stop criteria are concerned, the investigators feel that by 
the time they have studied three or four patients they will know whether the therapy is 
worthwhile and has a chance of succeeding. He said he doubted whether more than two 
or three patients could be treated in the first year. Since the investigators will be 
reporting back to the HGTS every six months or so, they will be kept apprised of the 
status of these patients. He added that if two treatment-related deaths occur, the 
investigators will consider it necessary to stop the protocol. 
As to effectiveness. Dr. Blaese cited the recent work of Dr. Bordignon looking at the 
effect of the gene-transduced cells in BNX mice, as suggesting that having the gene 
intracellularly is an advantage. He presented a table in the handout which showed that 
cell lines transduced with intracellular ADA had a potential advantage over non- 
transduced cell lines in tissue culture in the absence of toxic levels of deoxyadenosine. 
Dr. Blaese distributed a handout to address the issue of half-life of the transduced gene. 
This was based on half-life determination of TILs in five patients, showing a half-life of 
4-5 days. Dr. Kelley asked if this was in the presence of IL-2. Dr. Blaese replied that 
patients did receive IL-2 for varying numbers of days during the first five days after 
infusion, but that in studies with monkeys without IL-2 the gene could still be seen, as 
[164] 
Recombinant DNA Research, Volume 14 
