Britain's second-biggest drug manufacturer, AstraZeneca withdrew the clinical trials of its prostate cancer drug, zibotentan, as the beneficial efficacy of the drug was proving to be questionable.
A Phase III study was cancelled when it was established that the drug was no better than standard therapy. The Independent Data Monitoring Committee (IDMC) reviewed the matter and reported that there was no conclusive evidence that the drug would help patients with prostate tumors live longer or delay progression of the disease. When these primary targets - disease progression-free survival and overall survival - were not met, it was decided that it would be best to discontinue the trials.
Prostate cancer, the second most common cancer affecting men, especially in the West, poses the danger of developing into non-metastatic castrate-resistant prostate tumors (CRPC) when it does not respond to treatment.
Zibotentan was expected to block the endothelin pathway that becomes uncontrolled with the advance of the disease, and thus slow down the spread of the cancer cells. Unfortunately, the ENTHUSE (Endothelin A Use) clinical trial programme did not find this happening.
There is one more study that AstraZenta hopes to finish with successful results. The study will evaluate zibotentan plus chemotherapy rather than just chemotherapy alone, in men whose cancer had spread and who have been prescribed treatment with chemotherapy.
This is not the first disappointment AstraZenta faces in the trial studies of its drugs. It had to deal with failures in Recentin in colon cancer, Vandetanib for lung cancer, Motavizumab for respiratory problems in children, and Brilinta, a blood thinning drug for heart problems.
Although AstraZeneca has led the field in its innovative medicines, observers feel that the company has to be more thorough in its research strategies.