4'-O-tetrahydropyranyladriamycin as a potential new antitumor agent.

Chemotherapy with 4'-O-tetrahydropyranyladriamycin (THP-ADM), a new derivative of Adriamycin, was equally or more effective against several experimental mouse tumors than it was with Adriamycin (ADM). When mice with P388 leukemia were given i.p. injections of THP-ADM or ADM daily for 9 consecutive days, the maximum increases in life span (ILSs) of the mice were 190 and 175%, respectively. Eight of 24 mice treated with THP-ADM were free of tumor, while one of 24 mice treated with ADM was free of tumor. A single i.p. injection of either drug was also effective; maximum ILS was 170% for mice treated with THP-ADM and 240% for those treated with ADM. Nine of 12 mice were found to be free of tumor. THP-ADM was equally or slightly more effective against P388 leukemia than was ADM when either drug was given i.v. The maximum ILS was 106% with THP-ADM and 77% with ADM when the drug was given for 9 consecutive days. Single i.v. injections of THP-ADM or ADM were almost equally (ILS, 100%) effective. Chemotherapy with THP-ADM was also very effective against L1210 leukemia. THP-ADM administered i.p. five times, every other day starting from Day 1, was more effective than ADM was against Lewis lung carcinoma, B16 melanoma, and colon adenocarcinoma 38 inoculated s.c. In the study with Lewis lung carcinoma, metastasis to the lungs was well suppressed by THP-ADM. ADM was more effective than was THP-ADM against colon adenocarcinoma 26. Because THP-ADM was more cytotoxic than or almost equally as cytotoxic as ADM against the established cell lines from the above mouse tumors, we suggest that THP-ADM is more efficiently transported into cultured cells.