Patients with metastatic prostate cancer resistant to hormones and docetaxel were treated with vinflunine (320 mg/m(2) every 21 days), a new vinca alkaloid with improved preclinical activity. Only 1 of 36 patients (3%) had partial response; the median progression-free survival (PFS) was 2.1 months. Treatment was well tolerated, with myelosuppression as the only frequent toxicity. Vinflunine has a low level of activity in the treatment of refractory metastatic prostate cancer, and should not be further developed for this indication.