Court rules Sanofi-Aventis’ Lovenox patent is unenforceable

NEW YORK A federal court has ruled that the patent for Sanofi-Aventis’ blood-thinning drug, Lovenox, is unenforceable.

The U.S. Federal Court of Appeals for the Federal Circuit made the decision after Sanofi-Aventis appealed a ruling by the U.S. District Court of California that the company intended to deceive the U.S. Patent and Trademark Office by withholding information when it filed for patents ‘618 and ‘743 for Lovenox, the brand name for injected enoxaparin sodium.

Aventis had sued two manufacturers in the district court after they filed ANDAs for Paragraph IV for generic versions of the drug.

After losing in the district court, Aventis appealed to the appellate court, which upheld the block on the patents, but found error in the district court’s ruling on intent to deceive, sending the case back to the lower court. The district court found that the patents were unenforceable due to inequitable conduct, and the appeals court upheld the lower court’s second decision.