E0771 Tumors Research Articles

Effective combination therapy of metastatic murine solid tumors with edatrexate and the vinca alkaloids, vinblastine, navelbine and vindesine

Studies are described in which a new folate analogue, edatrexate (EDX), in combination with the vinca alkaloids, vinblastine (VBL), navelbine (NVB) or vindesine (DVA) was evaluated against E0771 mammary adenocarcinoma, T241 fibrosarcoma and the Lewis lung tumor. Each of the four agents when given individually to animals 3 days after transplant of these tumors resulted in increases in survival of 53-143%. The relative effectiveness of these agents was (in increasing order) VBL, NVB congruent to DVA, EDX, with no long-term survivors obtained with any. Combination therapy with EDX and vinca alkaloids required dosage attenuation but was still markedly more effective. Treatment of E0771 and T241 tumors with EDX and either NVB or DVA increased survival 3- to 4-fold compared with therapy with individual agents and yielded 40-70% long-term survivors, while EDX with VBL increased survival 2- to 3-fold and yielded 20-40% long-term survivors. Simultaneous or sequential (EDX given 24 h before vinca alkaloid) administration of combined therapy was equally effective. Sequential administration of these agents at the same doses in the reverse order was highly toxic and required further dosage attenuation which compromised efficacy. Effects of these combinations against the Lewis Lung tumor were not as pronounced and were somewhat schedule-dependent. Simultaneous administration of EDX with VBL, NVB or DVA increased survival 2- to 3-fold over that obtained with single agents alone and yielded 10-40% long-term survivors, while sequential administration increased survival < 2-fold over that obtained with single agents and yielded 0-20% long-term survivors. These results suggest that combined therapy with these agents in patients may have appreciable utility and provide a basis for further clinical trials.

New folate analogs of the 10-deaza-aminopterin series

A group of folate analogs of the 10-deaza-aminopterin series, which were designed on the basis of the results of an intensive biochemical and pharmacokinetic program, have been examined in therapy experiments utilizing a group of murine tumor models. These new analogs were found to be markedly superior to methotrexate against four of five ascites tumors (L1210 leukemia, Sarcoma 180, Ehrlich carcinoma and Tapper carcinosarcoma) and against four of five solid tumors (S180, Tapper carcinosarcoma, E0771 mammary adenocarcinoma, Lewis lung carcinoma, and T241 sarcoma). Analogs alkylated (methyl or ethyl) at the 10 position of 10-deaza-aminopterin were found to be the most effective of the group. These analogs achieved log10 reduction in tumor burden several-fold greater in magnitude than methotrexate against L1210 and S180 ascites tumors and there were also long-term survivors. 10-Deaza-aminopterin itself gave a result intermediate between those obtained with the 10-alkyl derivatives and methotrexate. Against the solid forms of the Tapper tumor some partial regressions were obtained with methotrexate and 10-deaza-aminopterin, but a far greater number, extending over a longer period were obtained with the 10-ethyl derivative of 10-deaza-aminopterin. Against the E0771 tumor, 10-deaza-aminopterin was 2-fold and the ethyl derivative of 10-deaza-aminopterin was greater than 5-fold more effective than methotrexate in retarding tumor growth. Evidence for partial regressions and marked effects against metastatic disease were also obtained in the case of the 10-alkyl derivative. Similar results were also obtained with the T241 sarcoma. For Lewis lung carcinoma the relative potency was about the same but overall antitumor effects were more modest.