Recombinant DNA Advisory Committee - 06/1-2/92 
To determine if the PCR positivity was a result of the CD34( + ) blast population, 
Fluorescence Activated Cell Sorter separation was performed on the patient's peripheral 
blood mononuclear cells. These cells were sorted into CD34( + )/CD13( + ) blast 
populations and normal peripheral blood mononuclear cells. Results indicate that the 
CD34( + ) subset of the PCR positive peripheral blood mononuclear cells were PCR 
negative for the neomycin resistance gene. Approximately 3% of the malignant blasts 
yielded G418 resistant colonies. Semiquantitative PCR on cDNA from these blasts 
indicated that between 1% and 10% were neomycin resistance positive. The neomycin 
resistance positivity could be a result of marked normal progenitor cells, but Dr. Brenner 
stated that this conclusion is unlikely because the actual number of neomycin resistant 
cells is too large to arise from normal progenitor cells. 
Dr. Brenner stated that another 20 patients will be entered into the protocol, 10 with 
neuroblastoma and 10 with AML. At the end of this time, the frequency of marked cells 
will be assessed; and a decision will be made regarding future directions. If several more 
marked relapses are observed, purging procedures will be reconsidered. 
Dr. Murray asked the RAC if they had any further questions for Dr. Brenner regarding 
the status of his approved protocols. 
Mr. Capron asked Dr. Brenner to expand on his plans if more marked relapses are 
observed. Dr. Brenner stated that if future relapses occur, he would design a two 
marker bone marrow purging protocol. Mr. Capron asked Dr. Brenner why he would 
not initiate this purging protocol immediately. Dr. Brenner stated that the data is still 
premature and is based on the results obtained from one patient. More patients would 
have to be evaluated to confirm the marked relapse result. 
Dr. Murray noted that it would be useful for the RAC to receive any abstracts or papers 
that Dr. Brenner intends to submit for publication. 
IV. PROPOSED ADDITION TO APPENDIX D OF THE NIH GUIDELINES REGARDING 
A HUMAN GENE TRANSFER PROTOCOL ENTITLED A PHASE I STUDY OF 
CYTOKINE-GENE MODIFIED AUTOLOGOUS NEUROBLASTOMA CELLS FOR 
TREATMENT OF RELAPSED/REFRACTORY NEUROBLASTOMA /DR. BRENNER: 
Review-Dr. Parkman 
Dr. Murray called on Dr. Parkman to present his review. Dr. Parkman provided an 
overview of the protocol submitted by Dr. Malcolm Brenner of St. Jude Children's 
Research Hospital, Memphis, Tennessee. Dr. Parkman described the proposed vector as 
a derivative of a previously approved vector that now contains a gene coding for 
interleukin-2 (IL-2). This vector has a cytomegalovirus (CMV) promoter. The 
[674] 
Recombinant DNA Research, Volume 15 
