Preclinical studies of the combination of mafosfamide (Asta-Z 7654) and etoposide (VP-16-213) for purging leukemic autologous marrow.
In the present study we evaluated the effect of etoposide (VP-16-213) compared to mafosfamide-cyclohexylamine (Asta-Z 7654) on normal granulocyte-macrophage colony-forming unit (GM-CFU) growth, T-cell response to mitogens, and a clonogenic promyelocytic cell line (HL-60). The incubation time (30 min vs 60 min) appeared to be a fundamental parameter. The GM-CFU recovery was 14.4% +/- 7.3% and 1.4% +/- 2.3%, respectively, at 50 micrograms/ml Asta-Z 7654, and 17.6% +/- 8.6% and 3.00% +/- 2.4%, respectively, at 50 micrograms/ml VP-16. ASTA-Z at 50 micrograms/ml was effective in inhibiting the T-cell response to phytohemagglutinin (98.7% +/- 1.2%), whereas VP-16 was not (2.3% +/- 1.7%). With the combined chemical agents ranging from 10 to 20 micrograms/ml for each drug, we obtained a better GM-CFU recovery (five to ten times) using a middle term liquid culture (21-day incubation) than with the standard colony assay (plated immediately after treatment). When using HL-60 cells as the target, the antileukemic activity of VP-16 was lower than of Asta-Z 7654. Both compounds, at 20 micrograms/ml, resulted in 3.3- and 2.3-log cell killing, respectively. On the other hand, lower doses of Asta-Z 7654 combined with VP-16 (ranging from 10 to 15 micrograms/ml each) induced greater than 4-log cell killing after 60 min incubation time. These data suggest that VP-16 could be combined with Asta-Z provided that the dose is reduced for both drugs (less than 20 micrograms/ml).
Tamayo
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Laboratories of Cell Culture, Regional Blood Transfusion Center, Besançon, France.
Hervé
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P
D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001853:Bone Marrow / Q000187:drug effects* / Q000473:pathology; D016026:Bone Marrow Transplantation; D002460:Cell Line; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003520:Cyclophosphamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D005047:Etoposide / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007938:Leukemia / Q000473:pathology* / Q000628:therapy; D008213:Lymphocyte Activation / Q000187:drug effects; D013997:Time Factors; D014182:Transplantation, Autologous
D000970:Antineoplastic Agents; C048341:mafosfamide; D005047:Etoposide; D003520:Cyclophosphamide