I. DESCRIPTION OF PROPOSAL 
A. OBJECTIVES AND RATIONALE OF THE PROPOSED RESEARCH; 
Obi ective ; 
We will use in vitro molecular marking with the LNL6 vector to 
test if relapse after autologous transplant arises from residual 
systemic disease or neoplastic cells in autologous marrow used for 
transplantation. Specifically, we will test chronic myelogenous 
leukemia (CML) patients, re-induced into a second chronic phase or 
cytogenetic remission after accelerated phase or blast crisis, to 
determine if the origin of blastic relapse following autologous 
bone marrow and peripheral blood stem cell transplantation arises 
from residual systemic blastic cells or from viable blastic 
leukemia cells remaining in the autologous peripheral blood stem 
cell and marrow used for restoration of marrow function. 
Rationale : 
The patients in blastic or accelerated phase are first treated 
with Daunomycin, high dose Ara-C, and GM-CSF to re-induce the 
chronic phase from blast crisis. We expect that 50% of the patients 
will be converted into a cytogenetic remission with two courses of 
this therapy. The autologous marrow and peripheral blood stem cells 
are then collected and stored while the patient is in the chronic 
phase and has no blasts from the blastic phase detectable by 
morphology in the marrow and peripheral blood or when the patient 
is in cytogenetic remission. The ratio of leukemic blasts/total 
nucleated cells may be as high as 1/100 or as low as 1/100,000 
after in vivo chemotherapy. The infusion of the autologous 
hematopoietic cells (peripheral blood and marrow) is then used for 
restoration of marrow function after TBI, VP-16, and cyclophospha- 
mide therapy. 20% of patients may remain in remission for greater 
than one year although the majority relapse before 12 months. 
The origin of relapse will be tested by marking the autologous 
cells with the LNL6 vector which is produced by Genetic Therapy, 
Inc. (GTI) , and which is approved by the Food and Drug 
Administration (FDA) for this purpose. Screening for the LNL6- 
associated NEO gene will be performed at the time of relapse by 
PCR. A PCR assay for the Philadelphia chromosome and its molecular 
correlate, the bcr-abl mRNA, will also be used to determine if the 
NEO positive blast cells at relapse in the patients are normal or 
leukemic. Fluorescence in situ hybridization (FISH) for the 9/22 
translocation will also be used. 
Rationale for Use of CML in 2nd Chronic Phase After Accelerated 
Phase or Blast Crisis ; 
The presence of the NEO gene in the blastic leukemic cells at 
relapse, especially if the integration sites are polyclonal, will 
suggest that relapse came from leukemia cells remaining in the 
autologous marrow which is infused rather than from residual 
systemic disease. In view of the fact that the remissions in some 
of the patients may last greater than one year, it is conceivable 
that relapse is occurring from blast cells which contaminate the 
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Recombinant DNA Research, Volume 14 
