Autologous Bone Marrow Transplantation - Blog Science Connections

746 Chemopurging
isoeffect. On the other hand, the combination of VCR plus 4-HC was
subadditive and even protective on normal marrow: doses of VCR below 1.0
/ug/ml (and in some instances, 5 jug/ml) allowed 4-HC to be given in the
combination at greater than its 1C
9 0
dose before achieving its IC 90
isoeffect.
The results of ex vivo chemotherapy on normal bone marrow of seven
patients are reported in Table 2.
In contrast to bone marrow, the toxicity of VCR in combination with 4-HC
was additive or superadditive on both ALL and AML cell lines. The isoeffect
IC 90
doses of VCR (1 or 5 /jg/ml) plus 4-HC (5 /ig/ml) was significantly
superior to 4-HC alone at its 1C 90
dose of 5 fiq/m\ (P < .05) on ALL cell lines
REH and KM3. The superiority was evident but did not become significant
until VCR (5 jug/ml) was added on LAZ221, NALM-6, or AML cell line HL60,
and no drug or combination was able to cause a 1 -log reduction of K562 at its
IC 90
(paper submitted for publication).
Following the identification of the drug combination, VCR plus 4-HC, as
protective of normal bone marrow yet significantly superior in leukemic cell
kill to any single drug alone, clinical studies were initiated using VCR plus
4-HC for ex vivo marrow treatment in CR2 acute leukemia patients. A reserve
marrow of at least 1 x 10 8
cells/kg body weight was stored. The patient
subsequently completed a marrow harvest of 3-4 x 10 8
cells/kg body weight.
Light density cells were separated on a Percoll gradient (40-60% interphase;
specific gravity, 1.077 g/ml) and incubated in a slowly shaking water bath at 5
x 10 8 cells/ml at 37°C for 1 hour with VCR (1 jug/ml) plus 4-HC (5 ng/m\).
Following incubation, the cells were washed with RPMI 1640 solution
containing DNase (to avoid clumping), then filtered and frozen in dimethyl
sulfoxide and autologous serum in 4.5-ml aliquots.
Table 2. Percent of Granulocyte-Macrophage Colony-Forming Unit
Survival After Chemopurging Normal Bone Marrow 8
VCR (1 /ug/ml) + VCR (5 jug/ml) +
4-HC (5/jg/ml) 4-HC (5/ug/ml) 4-HC (5/jg/ml)
(x ± SEM) (x ± SEM) (x ± SEM)
4.1 ± 3.4 4.1 ± 2.4
6.8 ± 3.2 37.8 ± 1.4 —
4.0 ± 1.5 9.9 ± 5.3 —
17.6 ± 2.3 31.4 ± 5.2 5.2 ± 1.3
1.9 ± 1.1 4.4 ± 4.4 1.3 ± 0.6
12.6 ± 9.8 20.3 ± 1.7 16.3 ± 2.6
18.6 ± 1.3 19.4 ± 1.5 7.4 ± 1.0
9.4 ± 2.6 18.2 ± 4.9 7.6 ± 3.2
"Based on seven experiments.
Abbreviations: 4-HC, 4-hydroperoxycyclophosphamide; x, mean; SEM, standard
error of the mean; VCR, vincristine.