Some thoughts on experimental screening.

Experimental screening of anticancer drugs is discussed from the standpoint of the need for close co-operation between experimentalists and clinicans in developing therapies for human trials. Particular emphasis is given to screening analogues of known active drugs including the approaches in chemical synthesis and tests of experimental tumor activity, as well as the questions that determine clinical interest and capabilities for human trials. In the area of combinations of two or more drugs, the need for experimental systems providing data for rational design of clinical regimens is highlighted. Means for experimental evaluation of the major variables of dose ratio, dose schedule and sequence of drug administration are considered. Finally, the overall problems of drug screening are discussed within the context of combining drugs with other treatment modalities, such as surgery, radiotherapy, and immunotherapy. The complexities of designing better cancer treatment will require close interaction between experimental and clinical studies.