A phase II study of JM8, an analog of cisplatin, was carried out in 36 patients with advanced ovarian carcinoma. Thirty-three of these patients had recurrent carcinoma and had been heavily pretreated, either with cytotoxic drugs alone (28 patients) or with cytotoxic drugs and radiotherapy (5 patients). All patients had previously received cisplatin, either alone or as part of a combination, and some of them had previously been treated with as many as 4 different chemotherapy regimens. In addition, 3 patients with stage III ovarian carcinoma were treated with JM8 as first-line therapy. Twenty-eight of the 33 pretreated patients were evaluable for response, and 5 partial and 2 complete remissions were achieved. Of the 7 responders, 4 had previously been shown to be completely resistant to cisplatin, and a 5th had initially responded to, but subsequently relapsed, while receiving cisplatin. Renal, aural and neurotoxic effects were less than would have been expected with cisplatin, but hematologic toxic effects were common with a white blood cell count of < 2000 .times. 109/l recorded in 6 patients, and a platelet count of < 50,000 .times. 109/l recorded in 8 patients.