US FDA turns down ADVENTRX NSCLC drug Exelbine

US cancer and antiviral drug developer ADVENTRX Pharmaceuticals (NYSE Amex: ANX) says it received a complete response letter from the US Food and Drug Administration regarding its New Drug Application for Exelbine (vinorelbine injectable emulsion; also known as ANX-530) for the treatment of non-small cell lung cancer (NSCLC).

The company made the announcement after the close of stock markets. However, in after-hours trading, ADVENTRX shares lost more than half of their value, falling $1.39 to $1.15.

The FDA determined that it could not approve the Exelbine NDA in its present form. In particular, the complete response letter noted that, based on inspections at clinical sites, the authenticity of the drug products used in the pivotal bioequivalence trial (Study 530-01) could not be verified, which placed the results of the trial into question. The letter stated that the bioequivalence trial will need to be repeated to address this deficiency.