Merck u-turns on NDA for HIV drug

Merck & Co has said it will not submit a New Drug Application (NDA) to the US Food and Drug Administration (FDA) for its HIV treatment, vicriviroc, at this time.

The company has made the announcement after the drug failed to meet the primary efficacy endpoint in two phase III trials in treatment-experienced HIV-infected patients. These particular trials involved a high percentage of patients who had three or more active drugs in their optimised background therapy regimen.

Vicriviroc was one of the drugs acquired by Merck when it purchased Schering-Plough for $41.4bn last year.

Merck will continue with current phase II trials investigating vicriviroc as a therapy in treatment-naïve HIV-infected patients. In addition, those treatment-experienced patients from the phase III who have responded well to treatment with the drug, will continue to have access to the medicine.