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Court “Administers Relief” to Plaintiff in Affirming Preliminary Injunction for Painkiller Patent

February 01, 2001

Decision icon Decision

Last Month at the Federal Circuit - March 2001

Judges: Mayer (author), Michel, and Schall

In Purdue Pharma L.P. v. Boehringer Ingelheim GmbH, No. 00-1398 (Fed. Cir. Feb. 1, 2001), the Federal Circuit affirmed the district court’s grant of a preliminary injunction enjoining Boehringer Ingelheim GmbH; Roxane Laboratories, Inc.; and Boehringer Ingelheim Corp. (collectively “Roxane”) from infringing U.S. Patent Nos. 5,549,912 (“the ‘912 patent”); 5,508,042 (“the ‘042 patent”); and 5,656,295 (“the ‘295 patent”).

The patents-in-suit are directed to orally administered, controlled-release formulations of oxycodone for treatment of moderate to severe pain. They have virtually identical specifications and are CIPs to United States Patent No. 5,266,331 (“the ‘331 parent”). Purdue Pharma L.P.; The Purdue Frederick Company; The P.F. Laboratories, Inc.; and The Purdue Pharma Company (collectively “Purdue”) filed suit alleging that Roxane’s Roxycodone™ controlled-release oxycodone product infringed the patents and seeking a preliminary injunction. Roxane filed counterclaims of invalidity, based on anticipation and inequitable conduct. The district court granted the preliminary injunction after an evidentiary hearing with fact witnesses and experts.

The district court’s finding that Purdue would likely prove infringement turned on the construction of the claim term “administration.” Purdue contended that “administration” included single or multiple doses, steady state application of oxycodone. Roxane countered that according to the teachings of the specification, “administration” was limited to single-dose applications.

The Federal Circuit held that the district court had not erred when it found the claim language to be ambiguous and relied on the specification in construing this term to encompass multiple doses. This claim construction, according to the Federal Circuit, was consistent with and furthers the purpose of the invention as described in the specification. With respect to Roxane’s argument that the district court had impermissibly relied on extrinsic evidence to construe the claims, the Federal Circuit found that the district court’s claim construction was reasonable, independent of the extrinsic evidence.

The Federal Circuit also agreed with the district court’s finding that no real dispute existed, under this claim construction, and ruled that Roxane’s product infringes.

Turning to Roxane’s anticipation defense, the Federal Circuit ruled that the district court had not erred in finding that Purdue had made a strong showing that Roxane’s defense lacked substantial merit. Roxane contended that the ‘331 parent, having a different inventive entity than the patentsin- suit, was prior art. Purdue argued that the ‘331 parent was not prior art since the inventions disclosed in the patents-in-suit had been conceived and reduced to practice prior to the ‘331 parent filing date. The Federal Circuit ruled that the district court had not erred in holding that the ‘331 parent was not an anticipatory reference, given the declaration testimony of one of the inventors together with three exhibits that demonstrated conception and reduction to practice.

The Federal Circuit also affirmed the district court’s ruling that Purdue had adequately shown that Roxane’s inequitable conduct defense lacked substantial merit. During the prosecution of the ‘912 patent, Purdue filed a terminal disclaimer and acquiesced to the Examiner’s suggestion that the specification be amended to claim the benefit of the ‘331 parent filing date. Roxane contended that Purdue had committed inequitable conduct by not advising the Examiner that the ‘331 parent was prior art.

The Federal Circuit found that there was no evidence that Purdue had actively misled the Examiner, that Purdue had initially claimed priority to the ‘331 parent, and the claim to priority was logical. The Court stated: “We therefore decline to find inequitable conduct in the mere act of claiming priority to an earlier patent where the specifications, but not the claims, of the later patents are supported by the earlier patent.” Purdue Pharma, slip op. at 13.

Finally, because Purdue had successfully made a clear showing of a reasonable likelihood of success on the merits, it was entitled, under the prevailing rule in the Federal Circuit, to a rebuttable presumption of irreparable harm, and Roxane had failed to adequately rebut that presumption. Thus, the Federal Circuit affirmed the preliminary injunction order and remanded the case to the district court for further proceedings.