Reevaluation of a screening program for antineoplastic agents.

A total of 389 compounds and 40 antibiotics were active in the sequential screening program for antineoplastic agents at Lederle Laboratories during the past 8 years . Many of these compounds were folic acid , alkylating agents , or nicotinamide antagonists (thiad.tazoles) . The distribution of anti neoplastic activity against the 3-tumor screen (Sarcoma 180 , 6C3HED ym, and 72j mammary adenocarcinoma) was reviewed . Of the compounds , 78 . 4 and 10 . 3% were specifically active against the 72j tumor and the 6C3HED (Gardner) lymphosarcoma, respectively; 85 and 5% of the antibiotics were active against the 2 tumors . In contrast only 1 % of the compounds and 2 . 5% of the antibiotics were specifically active against Sarcoma 180 : azaserine , 2 folic acid antagonists , . tr, and an antibiotic preparation. These 5 substances seemed like a small return for the effort expended in testing with Sar coma 180 during the last 8 years . The importance of the 3 tumor types to the sequential screening program was further examined by reviewing the activity of 36 known carcinostatic compounds . Of , 34 were active against either the 72j or the 6C3HED tumors or both . None of the 3 tumors detected vincaleuko blastine sulfate (VLB). Azaserine was the only substance which required Sarcoma 180 testing for detection. It was concluded that a sequential antineoplastic screening program with only the 72j and 6C3HED tumors would have found almost all the known compounds and all clinically useful compounds now detected by the 3-tumor screen.