Cubist Pharmaceuticals Inc has received notification from the U.S. Food & Drug Administration (FDA) that the agency now anticipates completing its priority review of the Cidecin (daptomycin for injection) New Drug Application (NDA) on or before September 20, 2003, a three-month extension of tomorrow's original action date. Cubist continues to anticipate the approval and launch of Cidecin by the end of 2003.

The extension is a result of the agency classifying a recent response to a question concerning the reformatting of certain data sets as a major amendment to the application. Under FDA standard operating procedures, the agency has reset the PDUFA (Prescription Drug User Fee Act) action date in order to review the reformatted data.

"As with any priority review, both the FDA and the sponsor are committed to working through a large number of issues during a very short period of time," said Cubist's President & CEO Michael W. Bonney. "We appreciate the agency's cooperative approach to working with us and believe this action to be the next best outcome to an approval. This submission of reformatted data sets resulted from interactions with the agency when unforeseen technical difficulties with the electronic submission became apparent, not from specific questions regarding the safety or efficacy of Cidecin. We expect that these reformatted data sets will allow the agency to complete its priority review of this NDA by the new PDUFA action date and expect the impact on our launch timing to be minimal."

Cubist also announced today that the FDA has completed pre-approval inspections of daptomycin manufacturing facilities, and that previously scheduled labeling discussions have been postponed. Cubist anticipates these discussions will occur during the extension period.