Hepatotoxicity of hycanthone in patients with metastatic breast cancer

Hycanthone is an antischistosomal drug with promising antitumor activity against experimental animal tumors. In phase I clinical trials, hepatitis weas the dose-limiting toxic effect and a dose of 60-70 mg/m2/day for 5 days was reported as the maximum-tolerated dose. In a phase II study of hycanthone in patients with breast cancer we have recently observed severe hepatotoxicity, even at lower doses, which resulted in two drug-related deaths. From this study and the previously available data, we conclude that this drug is too toxic for human trials at the currently recommended doses. Its radiosensitizing effect may be worth exploring at a lower dose level.