Coumarin (1,2-benzopyrone) for the treatment of prostatic carcinoma.

The unavailability of effective treatment for metastatic hormone-refractory and clinically localized but pathologically unfavorable prostatic carcinoma warrants trial of new and promising treatments. Preliminary studies in patients with metastatic disease have shown (a) subjective but no objective responses to 100 mg coumarin and cimetidine daily; (b) objective responses in 3 of 40 patients treated with 3 g coumarin daily, all of whom had normal performance status and 1 of whom remains with three resolved bone metastases and stable prostate-specific antigen levels after 4 years; (c) toxicity only in bedridden patients. We recently initiated two multi-center trials of 1 g coumarin daily. Metastatic prostatic carcinoma patients of normal performance status were treated in a phase II trial. Patients who had been treated by radical prostatectomy, but had surgical margin, seminal vesicle or lymph node involvement or detectable prostate-specific antigen after radical prostatectomy, were randomized to coumarin or placebo.