A phase II trial of the new anthrapyrazole piroxantrone was conducted by the Southwest Oncology Group in advanced ovarian carcinoma. The objective were to evaluate its response rate and toxicity in patients who had disease persistence, progression, or recurrence either during or after platinum-containing chemotherapy. A two-stage statistical design targeted accrual to 15 eligible patients if no responses were observed. The piroxantrone starting dose was 120 mg/m2, with the provision to escalate to 150 and 180 mg/m2. There were 16 eligible patients, all of whom had received either one (12 patients) or two (4 patients) prior platinum-containing regimens; one patient had received doxorubicin. Fourteen of the 16 patients were enrolled either at the time of disease persistence/progression during initial chemotherapy or with recurrence or progression within 6 months of the previous platinum-based remain. One to 5 cycles of piroxantrone were given. Dose escalation was feasible in 7 patients but was prevented in the other 9 by neutropenia. Maximum toxicity for all cycles was none or grade 1 in 2 patients; grade 2, 5; grade 3, 8; and grade 4, 1. All but one of the grade 3 or 4 events was from myelosuppression; there were no adverse cardiac events. No responses were observed. Thus, piroxantrone appears inactive in patients with persistent, progressive, or recurrent ovarian cancer who recently had received a platinum-based regimen.