A phase II trial of piroxantrone in disseminated malignant melanoma. A Southwest Oncology Group study.

Piroxantrone is one of the anthrapyrazoles developed in an effort to combine the broad antitumor activity of the anthracyclines with decreased myocardial toxicity. It has shown activity in metastatic melanoma during phase I trials. The Southwest Oncology Group (SWOG) conducted a phase II trial in disseminated malignant melanoma with piroxantrone administered at 150 mg/m2 intravenously over 1 h every 21 days, based upon the phase I experience. Forty-six eligible patients were registered to the trial and 44 were evaluable for response. Two partial responses, Wayne of 6 and 9 months duration were observed for an overall response rate of 5% (95% confidence interval 1%-15%). Thirty-six of 46 eligible patients have died with an estimated median survival of 5 months (95% confidence interval 3-8 months). Toxicities were tolerable with granulocytopenia being the predominant toxicity. Based upon the observed response rate, it is concluded that piroxantrone administered at this dose and schedule has detectable but minimal activity, and does not warrant further investigation in this disease.