Sabarubicin (MEN-10755), a new synthetic anthracycline analogue, was evaluated for safety and efficacy in a multicentre phase II study in patients with advanced hormone refractory prostate cancer (HRPC). Thirty seven patients were included, of which 34 were evaluable for PSA response according to Bubley's criteria. Sabarubicin was administered as a short (30 min) intravenous infusion at a dose of 80 mg/m(2) every 3 weeks. The main toxicity consisted of grade 3/4 neutropenia in 24 patients (64.9%), with grade 3/4 febrile neutropenia occurring in one patient only. Grade 3/4 cardiotoxicity was observed in 4 patients including one ineligible. Other toxicities were mild. Nine patients achieved a PSA response (26.5%), 10 patients had stable disease (29.4%) and 14 patients disease progression (41.2%). One patient (2.9%) had a PSA response that was not confirmed by repeat PSA testing. The objective response rate according to RECIST criteria was 6.7% in 15 patients with measurable disease. The median duration of PSA responses was relatively long 7.1 months (95% CI 4.9-20.7) as was the median time to treatment progression in patients with stable disease. The median overall survival was 18.7 months (95% CI 9.1-N), comparable to results recently observed in taxotere-containing regimens. To confirm and extend these results, further testing of sabarubicin in larger trials is warranted.