Experimental chemotherapy with 5-arylpyrimidine antifolates: preliminary studies on toxicity and responsiveness of sarcoma 180 to DDMP (NSC-19494) and DDMP with citrovorum factor (NSC-3590).

The 5-arylpyrimidine antifolate DDMP showed appreciable therapeutic activity against an ascitic form of Sarcoma 180 in BD2F1 mice. Antitumor effects were highly schedule and dose dependent at a limited number of doses within the range of 8--40 mg/kg. The best results (increased lifespan = 112%) were obtained with two doses of DDMP at 40 mg/kg given 4 days apart. The incorporation of citrovorum factor rescue in dose schedules with DDMP appeared to improve the therapeutic index. In multiple-dose schedules with citrovorum factor allowing an average of eight doses of DDMP at a maximum level of 16 mg/kg, increases in median lifespan were greater than 158% with a number of long-term survivors.