A phase II study of vinorelbine and estramustine in patients with hormone-resistant prostate cancer

Abstract

Introduction: This phase II study was designed to evaluate the efficacy of vinorelbine in combination with estramustine in patients with chemotherapy-naïve hormone-refractory prostate cancer.

Material and methods: Patients received vinorelbine (i.v. 25 mg/m2) on days 1 and 8 every 3 weeks and estramustine (oral, 600 mg/m2) daily. Eligible patients were required to have progressive metastatic disease following the first hormonal manipulation.

Results: Of the 51 patients enrolled (median age = 69 years), 84% presented bone involvement and 75% had at least two organs involved at the time of study entry and 47 were evaluable for treatment efficacy. Prostate specific antigen (PSA) response (> or =50% decrease) which was the primary efficacy criterion was reported in 21 patients (41.2%) in the intent-to-treat (ITT) population and in 20 patients (48.8%) in the per protocol (PP) population. Of the 7 patients with measurable disease, 2 achieved partial response. Median progression-free survival and overall survival were 4.7 months (range: 1.9-8.6) and 14.3 months (range: 4.2-21.2), respectively. Grade 3-4 neutropenia was reported in 6.1% of patients and in 1% of cycles. The incidence of complicated neutropenia (febrile neutropenia reported in 1 patient and septic shock with severe neutropenia reported in 2 patients) was 5.8%. The most frequent grade 3-4 non-haematological events (% of patients > or =5%) included anorexia (10%), thrombosis/embolism (8%), vomiting and hypotension (6% each). There were 3 toxic deaths (5.9 %) resulting from pulmonary embolism, angina pectoris, and septic shock. The impact of combined chemotherapy on the quality-of-life (QL) of the patients was assessed between baseline and the first evaluation scheduled at 6 weeks indicated a marked reduction in pain while the rest of the symptoms remained stable. Overall, health status improved slightly over the treatment period.

Conclusions: This study confirmed that the combination of vinorelbine and estramustine is an active regimen in patients with hormone-resistant prostate cancer who had not been treated previously with chemotherapy. Main toxicities included complicated neutropenia even though the incidence of severe neutropenia was low. We observed a higher incidence of toxic deaths which could have been related to the regimen of estramustine used in the study.