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Cubist Reveals Drug Patent Error

The company is working on fixing the technical error, which relates to antibiotic Cubicin.

Cubist Pharmaceuticals


said Wednesday that it found an error in a pharmaceutical composition patent, and subsequently has asked the Food and Drug Administration to delist the patent from the Orange Book, where the FDA publishes patent information on approved drug products.

The biopharmaceutical company said the technical error was related to U.S. patent No. RE39071, one of the patents for its lead product, Cubicin, an injectible antibiotic for skin infections. Specifically, the stereochemistry of an amino acid in the claimed chemical structures was incorrectly identified in the patent, which was originally issued to

Eli Lilly

(LLY) - Get Free Report

and is now owned by Cubist.

The error came to light while Cubist was preparing for another company's potential paragraph IV filing regarding Cubicin. Such a filing is made when another manufacturer wants to submit an abbreviated new-drug application (ANDA) for a generic version of a drug. A paragraph IV certification lists the patents that are either unenforceable or not infringed by the generic drug. The generic has to give notice of the filing to the company holding the patents in question (Cubist in this case).

Upon receiving paragraph IV certification, Cubist has 45 days to file an infringement suit. Filing a suit delays approval for 30 months, but if the company does not file the suit, the ANDA for the generic can be approved immediately.

Cubist said it will pursue the appropriate course of action in the U.S. Patent Office to correct the patent. "If and when the error is corrected,

the company will ask FDA to re-list the corrected patent in the Orange Book," it said in a release.

After a slight drop in the morning, Cubist shares were trading up a slight 0.5% at $23.16 Wednesday.