Antitumor activity of FCE 21336, a new prolactin lowering drug, on the MXT mouse mammary carcinoma.

The effect of a new prolactin-lowering drug, FCE 21336 [1-ethyl-3-(3'-dimethylaminopropyl)-3-(6'allylergoline-8'-beta-car bonyl)-urea diphosphate] was evaluated on the hormone-dependent MXT mouse mammary carcinoma. The compound at doses of 0.02, 0.2 and 2 mg/kg s.c., 5 days a week for 6 weeks, was effective against early tumors (start of treatment: 1 day after tumor transplantation), and was more potent than bromocriptine. When FCE 21336 was tested on advanced tumors (start of treatment: 24 days after tumor transplantation), tumor weight after 3 weeks of treatment with the doses of 0.2 and 2 mg/kg had increased 6 and 5 times, respectively, compared to an increase of 10 times for control groups.