High-dose carboplatin in refractory ovarian cancer patients.

Thirty previously treated refractory ovarian cancer patients, all of whom received prior therapy with cisplatin, were treated in a phase II trial with high-dose carboplatin (800 mg/m2 per cycle with cycles administered every 35 days). Patients were treated with high-dose carboplatin when they were no longer responding to prior therapy or had relapsed after an initial response. Objective responses were achieved in eight of 30 patients (27%) while ten patients had minor responses or stable disease. No responses were observed from high-dose carboplatin in patients who had progressive disease during prior therapy with a cisplatin-based regimen. The primary toxicity of high-dose carboplatin was myelosuppression with a median WBC nadir of 0.6 and a median platelet nadir of 6,500 after the first cycle of therapy. Myelosuppression was not particularly cumulative as 78% of patients were able to receive either 100% or 75% of the projected dose even with the fourth cycle of high-dose carboplatin. The gastrointestinal (GI) toxicity of carboplatin was mild and there was no clinically apparent nephrotoxicity or neurotoxicity. These results demonstrate that: there is marked cross-resistance between cisplatin and carboplatin, and high-dose carboplatin may be a potential alternative to high-dose cisplatin in the treatment of ovarian cancer patients.