Pfizer announced today that it has received an "approvable letter" from the U.S. Food and Drug Administration (FDA) for its HIV entry inhibitor Celsentri® (maraviroc). While not an official approval, such a letter typically means that the FDA is poised to grant marketing clearance for a drug once outstanding issues between the agency and manufacturer are settled.
According to a press release issued by Pfizer, Celsentri is still "under review as a therapy for treatment-experienced patients" and the company is continuing its discussions with the FDA "to address outstanding questions and to finalize the product labeling as soon as possible."
Potentially life-saving drugs, such as Celsentri, are subject to accelerated review by the FDA. If a drug qualifies for rapid approval, the agency has six months from the date the manufacturer submits its New Drug Application (NDA) to either grant or deny expedited marketing clearance. Celsentri was tapped for accelerated review in February 2007 and today marked the agency's official deadline to respond to Pfizer's December 2006 NDA filing.
In light of what appear to be unresolved issues involving Celsentri's labeling – the official description of the drug's indication for usage, efficacy, safety, and dosing, all of which is included in the package insert for the product – an approvable letter was issued in place of an official approval decision.
In April, an independent advisory committee to the FDA voted unanimously to recommend the approval of Celsentri for treatment-experienced HIV-positive patients. Celsentri binds to a protein on the membrane of CD4 cells called CCR5. Once it does this, HIV cannot successfully bind with the surface of CD4 cells, thus preventing the virus from infecting healthy cells.
Pfizer's press release noted that it is currently in the process of submitting marketing applications around the work to make Celsentri available globally.
Source: Pfizer Inc.
