Figure IB 
35 
I ' ' I I I I I 
0 
2 
3 4 5 6 7 8 
9 
A.- Coi»ol J ) 
Days 
•: rtmCotartMawM 
C S*cg i J- C o to t 
O. 'Kr4*C«bartMM 
Interestingly, the studies of Brenner have been positive, the AML cells 
of these patients are also positive at the 10% level at the time of 
relapse, suggesting that all of the cells of marrow exposed to the i 
safety-modified retroviruses are modified at the same level with the 
vector sequences. The data and our animal model data suggests that we I 
will be able to modify the normal hematopoietic stem cells of these ' 
patients with the retroviruses which are safety-modified and contain a 
functional transcription unit with MDR-1 cDNA. j 
Accordingly, we have proposed to modify the peripheral blood stem i 
cells of breast cancer patients, who are incompletely responsive to ; 
conventional dose chemotherapy, and whose expectation of dying from the 
disease (by virtue of adverse prognostic features) is 80% or more. In ; 
this program, we will harvest the peripheral blood stem cells, ( 
following non ablative dose of cyclophosphamide chemotherapy (4 gms/^) , 
purify the early progenitor cells through CellPro CD34 selection, and 
then modify the peripheral blood cells with a protocol outlined in ^ 
Appendix D. GCSF, 5 mcg/kg, will be given as a daily subcutaneous dose j 
starting with the completion of the non ablative dose chemotherapy. The 
purpose of this chemotherapy and GCSF is first to produce the optimal 
conditions for the collection of early progenitors from the peripheral ”1 
blood. This is a regimen with which The U.T. M.D. Anderson has had 
extensive experience in producing preparations which are very rich in , 
reconstituting cells, if the collections are started when the total 
white cell count is between 800/cu mm and 2,000/cu mm. A second 
purpose of this regimen is to produce conditions under which the cells Ji 
which are collected from the peripheral blood contains higher numbers 
of early hematopoietic precursor cells which are proliferating. This is 
necessary to generate conditions under which the early precursor cells ! 
will be modified by the MDR-1 virus, as the conditions of a recovering 
marrow produce that condition. The peripheral blood cells collected i 
are split into two halves, and one half is exposed to the virus after i 
CD34 selection. The CD34 selection is used to increase the frequency , 
of cells with long term reconstituting capability so as to increase 
their frequency of being modified by the virus. The protocol of non I 
[5261 
Recombinant DNA Research, Volume 19 
