1.0 PRECIS OF AMENDMENT 
We propose to use retroviral-mediated gene transfer of the 
neomycin-resistance marker gene into autologous bone marrow 
and peripheral blood stem cells to study the biology of 
hematopoietic reconstitution after transplantation and the 
feasibility of using this type of delivery system to 
transfer foreign genes to short and long-term reconstituting 
cells. We will apply identical retroviral transduction 
conditions and vectors to autologous bone marrow and 
peripheral blood stem cells harvested for transplantation *as 
part of three clinical protocols. These three protocols 
enroll patients with multiple myeloma, chronic myelogenous 
leukemia, or metastatic breast cancer. The protocols are 
being carried out in collaboration between two institutions: 
the National Institutes of Health (Clinical Hematology 
Branch, NHLBI and Medicine Branch, NCI) and the University 
of Virginia School of Medicine, Department of Hematology and 
Oncology. The decision to submit a "generic" genetic 
marking amendment for all three clinical protocols is based 
on the use of identical transduction conditions and vectors 
by the same group of investigators in each. 
Eligible patients will have 70% of their harvested bone 
marrow and- peripheral blood stem cells processed and 
cryopreserved as per the original protocols. The remaining 
30% will be enriched for cells carrying the CD34 antigen, a 
protein found on the surface of primitive progenitor and 
stem cells, and transduced with Neo* retroviral marking 
vector in vitro for a 72 hour period in the presence of 
hematopoietic growth factors. Myeloma and CML patients 
receiving both bone marrow and peripheral blood stem 
transplantation will have these two populations marked with 
two separate vectors. After conditioning chemoradiotherapy , 
both the transduced and the non-transduced populations will 
be returned to the patient. Molecular analysis for the 
marker gene will be carried out, and if successful short or 
long-term marking occurs, critical pilot information may be 
obtained regarding the biology of autologous reconstitution, 
the feasibility of retroviral gene transfer into 
hematopoietic cells, and the contribution of viable tumor 
cells within the autograft to disease relapse. 
Recombinant DNA Research, Volume 16 
[5] 
