The program consists of the evaluation of new anti-cancer drugs in three phases. I. The initial toxicologic evaluation of new candidate agents. The agents studied in this phase in the last year have been Piperazinedione, Pyrazofurin, Fluorouridine, and Anhydro- arabinosylfluorocytosine. II. The therapeutic evaluation of new agents. The compounds studied in this phase have been those which were also studied in Phase I. III. The study of combinations of agents in disease-oriented trials. The major programs during the last year have been in testicular, breast and gastrointestinal cancer and in soft tissue sarcomas. The second major program is the study of the clinical pharmacology of new agents. The compounds studied during the last year have included Anhydro-arabinosylfluorocytosine, Arabinosylcytosine, Piperazinedione, and Pyrazofurin.