Human Gene Therapy Subcommittee - 7/30/90 
to produce only 20-fold more than normally produced, but said 
that with selection they hope to be able to reach 100-fold. He 
added that they now had viral preparations available at titers of 
5 X 10® c.f.u./ml.; viral titer and availability of supernatant 
will not be a problem. Southern blots based on quantitative PCRs 
and survival in G418 show that transduction efficiencies are 10- 
20 percent, which is very similar to the LNL6 vector used in the 
N2/TIL protocol. 
Dr. Rosenberg said the study was a Phase I trial, which by nature 
is a trial to seek the maximum tolerated dose of the TIL^j^p, and 
that, if this trial is successful, a Phase II trial to evaluate 
the anticancer effects would be the normal way to proceed. This 
of course would have to be resubmitted for local approval, as 
well as approval by the HGTS and the RAC. However, each patient 
selected will have widely metastatic cancer and a life expectancy 
of only months. If substantial antitumor effects are seen they 
will be noted and carefully measured, as each patient will be his 
own control and will be receiving increasing numbers of cells. 
Regarding lysis. Dr. Rosenberg said that when target cells are 
treated with TNF or TNF and gamma interferon, the lysis is 
increased because TNF up-regulates major histocompatibility 
complex (MHC) antigens on the tumor cell surface when using 
exogenous TNF. However each TIL preparation has been checked for 
lysis and has been close to the same in 4-hour chromium release 
assays . 
As far as dose-response data are concerned. Dr. Rosenberg said 
that the investigators intend to begin with a one-third dose of 
IL-2 and that with dose escalation leeway is provided in terms of 
the number of doses that can be administered and when it is 
possible to withdraw IL-2. He noted that, even if 1/100 the dose 
of IL-2 were given for a long enough period, it could result in 
toxicity. Finally, if toxicity were to occur, there are three 
ways to deal with it: 
1. Stop giving IL-2, because the cells are dependent on 
IL-2 for survival; 
2. Administer steroids which have a lymphocytic effect in 
humans which should cause lysis of any cell which 
survives IL-2 withdrawal; and, 
3. Administer anti-TNF antibody. Dr. Rosenberg noted that 
several commercial firms are now aggressively pursuing 
techniques to produce anti-TNF antibody and that enough 
should be available by the time it is needed and could 
Recombinant DNA Research, Volume 14 
[83] 
