4'-O-tetrahydropyranyladriamycin has greater antineoplastic activity than adriamycin in various human tumours in vitro.

The sensitivities of 84 human tumor tissues (23 gastric, 8 colorectal cancers, 34 hepatomas, 6 breast, 6 lung cancers and 7 malignant lymphomas) to adriamycin (ADM) and 4'-0-tetrahydropyranyladriamycin (THP-ADM), a semisynthetic anthracycline glycoside, were determined using the in vitro succinate dehydrogenase inhibition (SDI) test. The succinate dehydrogenase (SD) activity of the tumor tissues was assayed following exposure to 6.9 microM of the drug for 3 days; sensitivity was considered positive when the SD activity decreased to below 50% of that of the control cells. In the case of exposure to THP-ADM, the SD activity in the tissue decreased and the decrease was more extensive in the gastric, colorectal cancers, hepatomas, lung cancers, with a statistically significant difference (P less than 0.001-P less than 0.05), but not in the breast cancers and malignant lymphomas. The rate of sensitivity was 70.2% for THP-ADM and 51.2% for ADM in the 84 tumor tissues. The percentage of tissues with a higher sensitivity to THP-ADM, compared to ADM, was 79.8%. As THP-ADM proved to be more cytotoxic than ADM to human tumors in vitro, this drug should be kept in mind when anti-cancer chemotherapy is designed.