N-Trifluoroacetyladriamycin-14-valerate (AD-32) is superior to Adriamycin in murine L1210 and P388 leukemias and in a number of solid tumor systems, including Ridgway osteogenic sarcoma and Lewis lung carcinoma. In preclinical toxicology studies, AD-32 was less toxic than Adriamycin in both tumor- and non-tumor-being mice and in rabbits. An initial clinical trial was carried out in 23 patients who received a total of 74 courses of AD-32 over a dose range of 100--700 mg/m2 administered at 21-day intervals. Hydrocortisone given during the period of infusion prevented all clinical manifestations of acute toxicity. The AD-32 dose-limiting toxicity, leukopenia, was comparable to that of Adriamycin at a dose of 10:1, but at these equivalently myelosuppressive doses, AD-32 induced less gastrointestinal toxicity and alopecia than Adriamycin and it did not cause local tissue damage following inadvertent paravenous extravasation. Although two responses are reported, the therapeutic activity of AD-32 cannot be assessed because of an inadequate number of patients in any given tumor type. A phase II study is being initiated at a dose of 600 mg/m2 given at 21-day intervals.