Who Took Away The Better Half? Lipitor Patent Battle IV

Battle II Round I: US District Court Pfizer sued Ranbaxy in response of Ranbaxy’s Abbreviated New Drug Application (ANDA) No. 76-477 filed with FDA, seeking marketing approval for generic bioequivalent of Atorvastatin Calcium. Pfizer filed patent infringement lawsuit in the U.S. District Court for the District Court of Delaware alleging infringement of U.S. Patent # 4,681,893 (the ‘893 patent) and U.S. Patent # 5,273,995 (the ‘995 patent) under 35 U.S.C. § 271 (e)(2). In particular, Pfizer alleges infringement of claims 1-4, 8 and 9 of the ‘893 patent and claim 6 of the ‘995 patent. In response, Ranbaxy counterclaimed Pfizer arguments alleging that it does not infringe either the ‘893 or ‘995 patents. Ranbaxy also challenged the validity of the patent term extension granted by the USPTO for the ‘893 patent. With regard to the ‘995 patent, Ranbaxy contented that the claim 6 of the ‘995 patent is invalid for double patenting, obviousness and anticipation. Ranbaxy also contended that the ‘995 patent is unenforceable as a result of inequitable conduct by Warner-Lambert Co. before the USPTO. Judge Farnan Jr. in his Memorandum Opinion rendered the Court’s findings of fact and conclusion of law on the issues raised during the trial. In his Memorandum Opinion, the Judge carefully applied the legal principles of claim construction with respect to the ‘893 and ‘995 patents followed by applicable legal principles of infringement. The ‘893 patent With regard to the ‘893 patent, claim construction dispute arises regarding the structural formula I depicted by independent claim 1. According to Ranbaxy, the recited structural formula I represents only a genus of racemates whereas Pfizer contended that claim 1 represents racemates as well as R-trans enantiomers, S-trans enantiomers and unequal mixtures of R-trans and S-trans enantiomers. To support its claim construction, Ranbaxy contended that: 1. by common convention, a racemate can be represented by depicting one of its constituent enantiomers. But the court ruled out this argument stating that Ranbaxy has not demonstrated that, to one skilled in the art, such a depiction always or even usually specifies a racemate.

2. the reaction sequences and examples of the ‘893 patent are directed to racemate. But the court ruled out this argument stating that the ‘893 patent is not limited to its examples and provides no indication that it should be so limited.

3. if the Court accepts Pfizer’s construction of the ‘893 patent, the patent is invalid for lack of written description, because the patent does not disclose any methods for making enantiomers. But the Court ruled out this argument stating that the generic formula description contained in the ‘893 patent is sufficient to satisfy the written description requirement, regardless of whether the specific isomeric compounds are individually described in the patent.

4. Warner-Lambert’s representations during the prosecution of foreign counterparts to the ‘893 patent demonstrate that the ‘893 patent is limited to racemate. But the Court ruled out this argument stating that Warner-Lambert’s statements during the prosecution of foreign counterparts of the ‘893 patent are irrelevant to the Court’s claim construction of the ‘893 patent issued in the United States. In sum, the Court concluded that its claim construction of the ‘893 patent is supported by the specification and the express language of the claim. The Court positioned that Ranbaxy’s claim construction is primarily based on extrinsic evidence, which is irrelevant to claim construction and inconsistent with the intrinsic evidence of the ‘893 patent. After considering the claim language, the specification and the prosecution history of the ‘893 patent, the Court concluded that the ‘893 patent is not limited to racemate and embrace all trans-form isomers, including enantinomeric atorvastatin calcium. Based on above claim construction, the Court concluded that Ranbaxy’s ANDA product literally infringes claims 1-4 of the ‘893 patent. The Court also concluded that Ranbaxy is likely to market or sell a composition containing atorvastatin calcium as embraced by claim 8 of the ‘893 patent, for use in the method claimed by claim 9 of the ‘893 patent for inhibiting cholesterol biosynthesis in a patient in need of such treatment. Therefore, the Court concluded that Ranbaxy literally infringes claim 8 and 9 of the ‘893 patent.

To be continued...