Sanofi-Aventis and partner Regeneron have suffered a setback in the clinic with the news that their investigational agent aflibercept has failed in a late-stage trial for non-small cell lung cancer.

Specifically, top-line data from the 913-patient Phase III VITAL trial evaluating aflibercept (also known as VEGF Trap) for the second-line treatment of NSCLC showed that adding the drug to the chemotherapy docetaxel did not meet the primary endpoint of improvement in overall survival compared with docetaxel plus placebo. However, the addition of aflibercept to docetaxel demonstrated activity as measured by secondary endpoints, ie progression free survival and an overall objective response rate (ORR) of 23.3% in the aflibercept arm compared to 8.9% for the placebo/chemotherapy combo.

The companies said they will conduct a detailed analysis of the efficacy and safety results of VITAL and present full results at an upcoming medical meeting. Debasish Roychowdhury, head of oncology at Sanofi, noted that "bringing new and innovative cancer therapies to patients can be incredibly challenging, especially in difficult-to-treat cancers such as second-line NSCLC”.

He added that Phase III trials of aflibercept in two other indications - metastatic colorectal cancer and hormone-refractory metastatic prostate cancer - are underway. Still the drug has suffered earlier setbacks: in September 2009, the firms stopped a late-stage trial of aflibercept for metastatic pancreatic cancer and was pulled in ovarian cancer in June.

Outside of oncology, Regeneron is developing aflibercept with Bayer as a treatment of central vein occlusion in the eye. On the basis of positive results in two Phase III studies, marketing submissions for VEGF Trap-Eye are planned in Europe and the USA during the first half of 2011.