Treatment of advanced malignant melanoma with coumarin and cimetidine: a pilot study.

Based on previous results demonstrating that coumarin and cimetidine render objective tumor regressions in renal cell carcinoma, we conducted a pilot study to determine whether these drugs possess activity against malignant melanoma. A total of 22 patients with advanced melanoma received 100 mg coumarin p.o. daily for 14 days; on day 15, cimetidine was added at an oral dose of 300 mg four times daily. Both drugs were continued until progression of disease. In all, 12 patients had previously been treated, but all patients had a favorable performance status. No response was observed in 19 patients. Two patients with a low tumor burden achieved a partial response and a third showed a minor response. There was no toxicity from this regimen. Although coumarin and cimetidine at this dose and schedule did not display significant activity in this study population, further studies are warranted to explore higher doses and focus on patients with relatively low tumor burdens.