Print PDF

Court Finds Paroxetine Patent Invalid Based on New Prior Art

April 08, 2005
Swan, Jennifer S.

Decision icon Decision

Last Month at the Federal Circuit - May 2005

Judges: Rader (author), Bryson, and Gajarsa

In SmithKline Beecham Corp. v. Apotex Corp., No. 03-1285 (Fed. Cir. Apr. 8, 2005), the Federal Circuit, sitting en banc, vacated the prior panel’s decision, SmithKline Beecham Corp. v. Apotex Corp., 365 F.3d 1306 (Fed. Cir. 2004), that claim 1 of U.S. Patent No. 4,721,723 (“the ‘723 patent”) was invalid under the “public use” bar of 35 U.S.C. § 102(b). The Court then remanded the case back to the panel for further proceedings.

In a new decision, SmithKline Beecham Corp. v. Apotex Corp., 403 F.3d 1331 (Fed. Cir. 2005), issued the same day, the panel again held that Apotex Corporation (“Apotex”) infringed claim 1, which recites a “crystalline paroxetine hydrochloride hemihydrate.” The panel found that claim 1 covers any amount of paroxetine hydrochloride hemihydrate without limitation and that the scope of this claim would be clear to those of skill in the art. The panel rejected the district court’s indefiniteness findings, stating that “the test for indefiniteness does not depend on a potential infringer’s ability to ascertain the nature of its own accused product to determine infringement, but instead on whether the claim delineates to a skilled artisan the bounds of the invention.” The panel adopted the district court’s factual finding that Apotex’s paroxetine hydrochloride anhydrate would contain paroxetine hydrochloride hemihydrate and, thus, found that under the correct claim construction, Apotex would infringe claim 1.

The Court, however, also held claim 1 of the ‘723 patent invalid, but this time on a different ground than public use. Following the en banc decision that vacated the public-use determination, the Federal Circuit reversed the district court and held that claim 1 of the ‘723 patent was inherently anticipated by U.S. Patent No. 4,007,196 (“the ‘196 patent”). Apotex had not appealed this decision to the Federal Circuit. Specifically, in its prior public-use opinion, the panel had noted that “the district court . . . determined that Apotex did not present clear and convincing evidence of inherent anticipation . . . . Apotex does not appeal that Ruling.” SB v. Apotex, 365 F.3d at 1315.

Nevertheless, in a split decision, the majority panel sua sponte reversed the district court and held the claim invalid for inherent anticipation over the ‘196 patent. The ‘196 patent does not disclose paroxetine hydrochloride, but discloses a maleate salt form of paroxetine. Although there was no evidence in the record that before the preparation of hemihydrate by the named inventors, anyone had ever practiced the ‘196 patent and obtained hemihydrate, and no evidence that anyone had ever recognized the existence of hemihydrate in the prior art, the majority held that the ‘196 patent necessarily produced undetectable amounts of paroxetine hydrochloride hemihydrate. Thus, the majority invalidated claim 1 under 35 U.S.C. § 102(b).

Judge Gajarsa filed a separate opinion concurring in the judgment. Judge Gajarsa would have held the ‘723 patent infringed by Apotex, but claim 1 invalid under 35 U.S.C. § 101.

Judge Newman dissented from the panel’s inherency holding, stating that it “contravenes long-established precedent.” SmithKline Beecham Corp. v. Apotex, 403 F.3d 1328, 1330 (Fed. Cir. 2005). Judge Newman stated that there was no evidence that PHC hemihydrate existed at the time the ‘196 patent was filed. She stated that the district court’s finding that the PHC hemihydrates had not been produced in 1975 was not shown to be clearly erroneous. As Judge Newman stated, inherent anticipation requires that the identical invention was known or its existence would have reasonably been known to a person of ordinary skill—not that it might have lain hidden in miniscule amounts, undetected, unsuspected, or unknown.