Recombinant DNA Adviaory Committee - 09/14-15/92 
the time of relapse, samples will be collected and assayed for the presence of the vectors 
in order to determine the efficacy of the purging procedure. 
All three of the primary reviewers noted that purging is a preferable procedure and were 
concerned about readministering unpurged bone marrow to these patients. Dr. 
Haselkom asked Dr. Brenner to respond to this issue. 
Other Comments 
Dr. Murray encouraged Dr. Brenner to submit written documentation as a follow-up to 
his previously approved protocols. Dr. Murray noted that written data has not been 
forthcoming from many investigators, and this information is critical to assessing the 
progress of these protocols. 
Dr. Parkman asked Dr. Brenner to discuss the standard of care at St. Jude for patients 
undergoing ABMT for neuroblastoma. 
Presentation-Dr. Brenner 
Dr. Brenner explained that the first gene transfer patient was treated at St. Jude exactly 
one year ago. Reports have been written regarding the two patients who have relapsed 
and the 13 patients who have been transplanted without relapse. These written reports 
will be forwarded to the Office of Recombinant DNA Activities (ORDA). 
Regarding the administration of unpurged marrow, Dr. Brenner said that it is not known 
whether relapse is caused by residual disease remaining in the marrow. Currently, his 
laboratory is attempting to solve this question with the AML protocol. 
The standard of care for neuroblastoma autologous transplant patients at St. Jude is to 
administer marrow that has not been purged. No data exists demonstrating that patient 
survival is increased in patients receiving purged marrow as opposed to unpurged 
marrow. This situation may be partially due to the fact that engraftment in these 
patients is somewhat slow. Relapse may be through a mixture of disease in the patient 
and residual disease in the harvested marrow. 
Discussion 
Dr. Parkman inquired about the specificities of the monoclonal antibodies that will be 
used in the purging system. Dr. Mills said that the antibodies that were selected for 
targeting neuroblastoma cells were chosen based on their high level of reactivity with a 
broad panel of neuroblastoma specimens. Data obtained from Dr. Don Hempstead's 
laboratory demonstrated that these antibodies reacted with 274 out of 275 neuroblastoma 
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Recombinant DNA Research, Volume 16 
