[Recent data on biological and clinical properties of radiosensitizers (author's transl)]

In the pursuit of a way to reduce the radioresistance due, among others, to hypoxia in solid tumors, research on radiosensitizers (notably the electron-affinic sensitizers) has been active for many years. The radiosensitization efficiency and the cytotoxic and transforming effects of a great number of substances was first studied in vitro. Then two drugs, metronidazole and misonidazole, were tested especially in vivo in animals; this research concerned their effect both on tumors and on normal tissues. After presenting an overview of the experimental results, we summarize the preliminary results of the first clinical trials with misonidazole. The general tolerance to this drug is now well known: its local influence on tumors and also normal tissues radiosensitivity is the object of most of the present clinical trials.