RESUMEN
BACKGROUND: The present exploratory phase II study was performed to evaluate the activity and tolerability of adding a second agent (gemcitabine) to the well-tolerated mitoxantrone/prednisone regimen in patients with locally advanced or metastatic prostate cancer no longer responsive to hormonal treatment. PATIENTS AND METHODS: Forty-three patients with hormone-refractory prostate cancer (HRPC) were included in the study from May 2000 to April 2004. Their median age was 71 years (range, 56-81) and their median Karnofsky performance status (KPS) was 90 (range, 70-100). The treatment schedule consisted of intravenous (i.v.) mitoxantrone (8 mg/m2 on day 1), i.v. gemcitabine 800 mg/m2 on days 1 and 8, recycled every 21 days and oral prednisone administered at a dose of 10 mg per day. Hormonal treatment with LHRH was continued in all patients. Up to six cycles of treatment were planned in the absence of progressive disease. RESULTS: Sixteen patients had measurable disease (six patients only measurable disease, ten patients bone disease plus measurable disease) and 27 patients had only bone disease. Concerning the PSA levels, a partial response (PR) was observed in 15 patients (38%), stable disease (SD) in 16 patients (41%) and progressive disease (PD) in eight patients (21%). The objective response was evaluable in 16 patients; one patient was not evaluable because he had received only one cycle. Ten patients (63%) had SD and five patients (31%) PD. In the ten evaluable patients with objective SD, depending upon the PSA response, three PR, six SD and one PD were observed. Among the five patients who progressed, three PD and two SD were observed as a PSA response. Pain remission was recorded in 15/41 patients (36%) and the KPS remained stable in most patients. The median overall survival was 15 months (range, 1-41) (95% CI: 10-20 months). The 1-year survival rate was 61%. Hematological toxicity was mild: G 3-4 neutropenia was observed in five (12%) patients. There were no neutropenic, fevers. No significant non-hematological toxicity was observed. CONCLUSION: The mitoxantrone, gemcitabine and prednisone combination, in accordance with the present regimen, was feasible, had a palliative effect, good tolerance and antitumor activity. Nonetheless, our results do not seem to be superior to those previously described for mitoxantrone plus prednisone.