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Yesterday, the Court of Appeals for the Federal Circuit affirmed a June 2007 district court decision finding that Mylan's (NASDAQ:MYL) generic version of Prilosec (omeprazole) does not infringe two AstraZeneca patents (NYSE:AZN), U.S. Patent Nos. 4,786,505 and 4,853,230.

Omeprazole is difficult to formulate because it is acid-labile.  Astra scientists developed a formulation that protects omeprazole from degradation in the acidic environment of the stomach.  Astra's formulation, which is claimed in the '505 and '230 patents, includes a core containing omeprazole and an alkaline reacting compound ["ARC"], a water soluble subcoat, and an outer enteric coating.

Mylan's ANDA product consists of an inert sugar/starch sphere; an active coating of omeprazole, talc and HPMC; two subcoatings; and an enteric coating.  Astra argued that the talc in Mylan's formulation contains carbonates, which serve as an ARC.  However, after a forty-two day bench trial, the district court determined that Astra failed to prove the presence of carbonates in Mylan's product.  The district court also determined that talc cannot satisfy the ARC limitation of the claims because the specification of the patents indicates that talc is not an ARC but rather an ordinary excipient, and because of statements Astra made during prosecution of the European counterpart of the '505 patent.

In the decision released on Tuesday, the Federal Circuit concluded that the district court's factual findings with respect to the presence or absence of carbonates in Mylan's formulation were not clearly erroneous.  Astra argued on appeal that the District Court applied the wrong legal standard by requiring "conclusive evidence" that carbonates were present in the talc, but the Federal Circuit disagreed, finding that the district court correctly applied the preponderance of the evidence standard.  Having determined that the district court did not clearly err in finding that Astra failed to prove the presence of "non-negligible amounts of carbonates" in Mylan's formulation, the Federal Circuit declined to address Astra's remaining arguments.

The omeprazole patent litigation began in 2000, when Astra sued several companies who filed ANDAs for generic Prilosec.  The lawsuits were consolidated as a multidistrict litigation and tried in two waves.  Mylan, which launched its generic Prilosec in August 2003, was part of the second wave.  Other companies in the second wave included Lek Pharmaceutical, Apotex, and Impax Labs.  In the same June 2007 decision in which it ruled in favor of Mylan, the district court also found that Lek's products do not infringe Astra's patents, and that Apotex's and Impax's (NASDAQ:IPXL) products do infringe.  Those determinations were appealed separately.

 Related Reading:

 

  • Mylan press release
  • 4-Jun-07 OBB post on district court decision
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