AstraZeneca halts phase III trial of ZIBOTENTAN in non-metastatic castrate resistant prostate cancer

AstraZeneca today announced that the phase III ENTHUSE Study 15, studying zibotentan monotherapy in patients with non-metastatic castrate resistant prostate cancer (CRPC), will be stopped following the results of an early efficacy review by the Independent Data Monitoring Committee (IDMC). The decision was made after this review indicated that zibotentan monotherapy was unlikely to meet its primary efficacy endpoints (progression free survival and overall survival) and therefore unlikely to benefit patients with non-metastatic CRPC.

AstraZeneca felt it was prudent to take an early view on the progress of Study 15 following the announcement in September 2010 that ENTHUSE Study 14, evaluating zibotentan monotherapy, did not show a significant improvement in the primary endpoint of overall survival in patients with metastatic CRPC.

Study 15 is part of the Phase III clinical trial programme, ENTHUSE, which was developed to evaluate the efficacy and safety of zibotentan in extending survival in men with CRPC. The discontinuation of Study 15 concludes the zibotentan monotherapy programme in CRPC. The full data from Study 15 will be published in due course.

ENTHUSE Study 33 is a trial using zibotentan in combination with standard chemotherapy in a more advanced metastatic CRPC setting. This trial will continue and full results are expected in the second half of 2011.