Efficacy of ifosfamide, dacarbazine, doxorubicin and cisplatin in human sarcoma xenografts.
The primary chemosensitivity of 16 highly malignant xenografted human soft-tissue sarcomas to ifosfamide, dacarbazine, adriamycin and cisplatin and the development of secondary drug resistance in two chemosensitive sarcoma cell lines was tested in the xenograft system. Single-dose, single-agent treatments with 350 mg kg-1 ifosfamide, 200 mg kg-1 dacarbazine, 10 mg kg-1 doxorubicin and 6.6 mg kg-1 cisplatin were administered and response measured as specific growth delay. Since ifosfamide induced unexpectedly higher toxicity, response was corrected based on the shape of the dose-response curve for ifosfamide. Taking a specific growth delay > 3 as the cut-off point for chemosensitivity, ifosfamide, dacarbazine, doxorubicin and cisplatin were effective in 10/16, 4/16, 2/16 and 1/16 sarcoma cell lines respectively. Five out of 16 sarcoma cell lines were resistant to all tested drugs. Ifosfamide-resistant sarcoma lines were also resistant to doxorubicin and cisplatin, indicating a high degree of cross-resistance. Dacarbazine was still effective in 1/6 ifosfamide-resistant sarcoma cell lines. Secondary drug resistance developed slowly after doxorubicin and ifosfamide pretreatments at moderate selection pressure and developed rapidly after dacarbazine pretreatment at high selection pressure.
Budach
W
W
Department of Radiation Oncology, West German Tumour Centre, University of Essen, Medical School.
Budach
V
V
Stuschke
M
M
Schmauder
B
B
Reipke
P
P
Scheulen
M E
ME
D000818:Animals; D002945:Cisplatin / Q000494:pharmacology*; D003606:Dacarbazine / Q000494:pharmacology*; D004317:Doxorubicin / Q000494:pharmacology*; D004351:Drug Resistance; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007069:Ifosfamide / Q000494:pharmacology*; D007928:Lethal Dose 50; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D012513:Sarcoma, Experimental / Q000188:drug therapy*; D016019:Survival Analysis; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000637:transplantation
D003606:Dacarbazine; D004317:Doxorubicin; D002945:Cisplatin; D007069:Ifosfamide