Pre-IDE Submission: Clinical Protocol 
Neuroblastoma Bone Marrow Purging System 
BAXTER HEALTHCARE CORPORATION, HYLAND DIVISION 
of the immunocytologic assay. Because of the sample size in the 
proposed Phase 2 study (12 patients), the likelihood that the Phase 
2 data will be statistically definitive data is small. It would require 
demonstration in 25 purged marrows of the absence of detectable 
tumor cells, at a sensitivity of 1 tumor cell in 100,000 bone 
marrow cells, to be 95 % confident that one would be at or below 
the detection limit in at least 88 % of patients. 
(4) The ability to detect marked neuroblastoma cells at relapse will 
establish the utility of gene marking for assessing the efficacy of 
purging. 
(5) The detection of marked neuroblastoma cells at relapse will 
indicate that transfused marrow does, in fact, contribute to 
neuroblastoma relapse and therefore, that tumor cell removal is of 
potential clinical benefit. 
(6) The data obtained from analysis of the marked neuroblasts from 
relapse marrow will allow the estimation of the number of patients 
that would be required to validate the clinical benefit of purging, 
and facilitate the design of such studies. 
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Recombinant DNA Research, Volume 16 
