Scheduling of combination chemotherapy for a murine melanoma, with the subrenal capsular assay.

The effect of varying schedules for administration of two drugs, dimethyl triazeno imidazole carboxamide (DTIC) and methylcyclohexyl chloroethyl nitrosourea (MeCCNU), was studied using the Harding-Passey Mouse melanoma in the subrenal capsular assay. The results of the assay indicate that the responses of the tumor varied depending on the schedule of administration. The best response, with a mean decrease in dimensions of 3.0 ocular micrometer units (+/- 1.12 SD), was noted with administration of DTIC on day 1 after tumor implantation, followed by MeCCNU on day 2. These results are similar to previously reported data in CD2F1 mice bearing intraperitoneal Harding-Passey melanoma and suggest that the subrenal capsular assay may be of use in determining the best combinations and schedules of administration for treatment of tumors.