Recombinant DNA Advisory Committee - 03/1-2/93 
protocol. The protocol was approved by a vote of 19 in favor, 0 opposed, and no 
abstentions. 
VI. ADDITION TO APPENDIX D OF THE NIH GUIDELINES REGARDING A HUMAN 
GENE TRANSFER PROTOCOL ENTITLED: ASSESSMENT OF THE EFFICACY OF 
PURGING BY USING GENE-MARKED AUTOLOGOUS MARROW 
TRANSPLANTATION FOR CHILDREN WITH ACUTE MYELOGENOUS LEUKEMIA 
IN FIRST COMPLETE REMISSION/ DRS. BRENNER, KRANCE, HESLOP, SANTANA, 
AND IHLE 
Review--Dr. Chase 
Dr. Walters called on Dr. Chase to present his primary review of the protocol submitted 
by Drs. Malcolm K. Brenner, Robert Krance, Helen E. Heslop, Victor Santana, and 
James Ihle of St. Jude Children's Research Hospital, Memphis, Tennessee. 
Dr. Chase explained this is a marking study in which two different retrovirus vectors, 
LNL6 and GINa, will be used to compare the efficacy of two bone marrow purging 
techniques, 4-hydroxyperoxicyclophosphamide (4-HC) and interleukin-2 (IL-2) activation 
of cytotoxic effector cells. Data from previous studies indicates that gene-marked 
malignant cells have been identified in the marrow of remission patients and can 
contribute to recurrent disease. Therefore, the current purging methods probably do not 
eliminate all of the malignant cells in the reinfused marrow. 
Review--Dr. Doi (presented by Dr. Chase) 
In Dr. Doi's absence, Dr. Walters asked Dr. Chase to summarize Dr. Doi's written 
comments regarding this protocol. 
Dr. Chase noted that the investigators had responded to all of Dr. Doi's written 
comments and questions. Dr. Doi had inquired whether it was possible to determine the 
percentage of relapsed cells that contained marker genes in the 2 marked relapse 
patients from the previous study. The investigators' response to this question was that 
2% of the relapse cells were marked; however, since only one-third of the reinfused 
marrow was transduced, the total number of marked cells could be as much as 6%. 
Dr. Chase commended the investigators for their responses regarding the patient sample 
size. A detailed discussion and published article about the sample size and power 
computations has been included. Dr. Chase suggested that all investigators should 
submit an analysis section according to these standards. He complemented Dr. Brenner 
on his clear explanation of the issues and recommended that the protocol be approved. 
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Recombinant DNA Research, Volume 17 
