Antitumor Activity of ME2303, a Fluorine‐containing Anthracycline, against Human Tumors Implanted in Nude Mice

A fluorine‐containing anthracyctine, ME2303, given intravenously once a week for 4 weeks at the maximum tolerated dose showed better therapeutic effects against 2 gastric, 3 lung and 2 human breast tumor xenografts than did adriamycin (ADM) at the maximum tolerated dose. Among the tumors, ME2303 showed a better effect against St‐40, a well‐differentiated human gastric adenocarcinoma, against which ADM showed only a marginal effect. Likewise, ME2303 was more effective against Lu‐24 human small cell carcinoma and MX‐1 human medullary tubular adenocarcinoma than ADM. Notably, the Lu‐24 tumor, developed in nude mice, disappeared after the treatment in 3 out of 6 mice. ME2303 would be an interesting compound for phase I and II clinical studies in the future