Columns = Number of patients studied 
Rows = Percentage of cell contributing to relapse which 
contain the LNL6 vector 
Data = Probability of detecting marked cells in at least 
one patient 
1 PT 
3 PT 
10 PT 
0.1% 
9.5% 
25.9% 
95% 
1.0% 
63.4% 
95.0% 
>99.99% 
If 1000 cells contribute to relapse the number of 
patients required to detect marked cells increases 
significantly with a 95% probability of detection in at 
least one of three patients even if the transduction 
efficiency was very low (0.1% of the population). 
Columns = Number of patients studied 
Rows = Percentage of cell contributing to relapse which 
contain the LNL6 vector 
Data = Probability of detecting marked cells in at least 
one patient 
1 PT 
3 PT 
10 PT 
0.1% 
63.2% 
95.0% 
>99.99% 
1.0% 
>99.99% 
>99.99% 
>99.99% 
8.2) Data Collection 
This will be a feasibility study to determine if 
retroviral-mediated gene transfer for autologous bone 
marrow transplantation can be detected in patients with 
recurrent leukemia following bone marrow transplantation 
and to document the safety of the procedure. We will be 
accruing 10 patients each with AML and ALL. With an 70- 
80% recurrence rate, we expect that 7-8 patients from 
each group can be evaluated for source of recurrence. 
Recombinant DNA Research, Volume 15 
[495] 
