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Preliminary Injunction Vacated Where ANDA Shows No Likelihood of Infringement

August 20, 2001

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Last Month at the Federal Circuit - September 2001

Judges: Rader (author), Mayer, and Newman

In Glaxo Group Ltd. v. Ranbaxy Pharmaceuticals, Inc., No. 01-1151 (Fed. Cir. Aug. 20, 2001), the Federal Circuit found error with the district court’s claim construction and, accordingly, vacated the district court’s preliminary injunction based on an Abbreviated New Drug Application (“ANDA”) filing.

Ranbaxy Pharmaceuticals, Inc. (“Ranbaxy”) had filed an ANDA to market a generic tablet form of cefuroxime axetil, a broad spectrum antibiotic. Glaxo Group Ltd. and Glaxo Wellcome, Inc. (collectively “Glaxo”) currently market cefuroxime axetil under the name Ceftin. Glaxo holds two patents that cover the drug: U.S. Patent No. 4,267,320 (“the ‘320 patent”) and U.S. Patent No. 4,562,181 (“the ‘181 patent”).

Solid cefuroxime axetil has two forms: (1) amorphous (without the molecules in any arrangement), and (2) crystalline (with the molecules in an ordered arrangement). Claim 1 of the ‘181 patent recites the drug as “essentially free from crystalline material.”

In granting the preliminary injunction, the district court had found that Ranbaxy’s proposed product, which contains about 10 to 15% crystalline cefuroxime axetil, would likely infringe the ‘181 patent.

In assessing the reasonable likelihood of Glaxo’s success on the merits, the Federal Circuit examined the prosecution history of the ‘181 patent and its foreign priority applipage cation. Originally, the application for the ‘181 patent contained an independent claim reciting the drug in a “substantially amorphous form” and a dependent claim reciting the drug as “essentially free from crystalline material.” In response to a 35 U.S.C. § 112, second paragraph, rejection for being indefinite, the claims were cancelled and a new claim was drafted. This claim combined the limitations of the two cancelled claims and that of a third claim.

The specification includes as an example a product that was described as “substantially amorphous.” During prosecution, this product was characterized to contain approximately 10% crystalline material. Reasoning that 10% crystalline material was “substantially amorphous,” the Federal Circuit concluded that the limitation of the cancelled dependent claim, “essentially free of crystalline material,” must necessarily be less than that.

Finally, citing Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 234 F.3d 558, 56 USPQ2d 1865 (Fed. Cir. 2000) (en banc) (cert. granted), the Court found that Glaxo cannot assert any scope of equivalents because the cancellation and addition of claims in the application in response to the § 112 rejection was a narrowing amendment related to the statutory requirements for a patent that gave rise to prosecution history estoppel.