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Claim for Antidepressant Found Invalid for Public Use

April 23, 2004

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Last Month at the Federal Circuit - May 2004

Judges: Rader (author), Bryson, and Gajarsa

In SmithKline Beecham Corp. v. Apotex Corp., No. 03-1285 (Fed. Cir. Apr. 23, 2004), the Federal Circuit rejected the district court’s claim construction that led to a SJ of noninfringement, but affirmed the SJ nonetheless, concluding that the claimed invention was invalid as having been in public use.

This appeal arose from an ANDA infringement action involving Paxil®, an antidepressant marketed by SmithKline Beecham Corporation (“SB”). Claim 1 of SB’s U.S. Patent No. 4,721,723 (“the ‘723 patent”) claims “crystalline paroxetine hydrochloride hemihydrate.” Paxil® contains paroxetine hydrochloride (“PHC”) in the hemihydrate crystalline form. Apotex Corporation (“Apotex”) sought to make a generic version of PHC, arguing that its PHC product was in an anhydrate crystalline form. SB alleged that Apotex’s proposed product would contain the patented hemihydrate crystalline form and would therefore infringe claim 1 of the ‘723 patent.

The district court interpreted claim 1 as limited to PHC hemihydrate in “commercially significant” amounts and found that such amounts would have to be in the “high double digits.” The district court supported this claim construction with a reference in the specification to the hemihydrate’s superior handling properties. The district court then found that Apotex’s proposed paroxetine drug did not contain commercially significant amounts of PHC hemihydrate and, therefore, would not infringe.

SB had argued that the claim covered a crystalline form of PHC that contains one molecule of bound water for every two molecules of PHC in the crystalline structure, and that any PHC that had this crystalline structure would infringe this claim. The district court found that such a claim construction would be indefinite.

The Federal Circuit disagreed with the district court’s claim construction, stating that claim construction “is not a policydriven inquiry. . . . it is a contextual interpretation of language. The scope of patent claims can neither be broadened nor narrowed based on abstract policy considerations regarding the effect of a particular claim meaning.” Slip op. at 11. The Federal Circuit then found that claim 1 covered any amount of PHC hemihydrate. The Federal Circuit also rejected the district court’s indefiniteness arguments, observing 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 Federal Circuit found that the scope of the claim is in fact clear to one of ordinary skill. The Federal Circuit then adopted the district court’s factual finding that Apotex’s PHC anhydrate would contain PHC hemihydrate, and found that under the correct claim construction, Apotex would infringe claim 1.

The Federal Circuit then turned to the public-use issue. The district court had granted SB’s motion for SJ that SB’s PHC clinical trials did not constitute a public use but rather were experimental. But, the Federal Circuit reversed. The Court assumed that the clinical trials were subject to satisfactory controls and otherwise properly conducted to fulfill their intended purpose— namely, to establish the efficacy and safety of PHC hemihydrate as an antidepressant drug for humans. Nevertheless, the Federal Circuit found that SB’s clinical trials could not be experimental, because the intended use of PHC was not recited in the claim. The Court warned that “a patentee should understand that testing the properties, uses, and commercial significance of a compound claimed solely in structural terms may start the clock under § 102(b) for filing a claim that is not limited by any property, commercially significant amount, or other use of the compound.” Slip op. at 23.

In a concurring opinion, Judge Gajarsa disagreed with the majority ruling on public-use invalidity, citing precedent that had found experimental use even where the intended use was not literally recited in the claim. Judge Gajarsa instead concluded that the Court should hold that patent claims drawn broadly enough to encompass products that spread, appear, and reproduce through natural processes are not patentable and invalid under 35 U.S.C. § 101, and that claim 1 of the ‘723 patent was such a claim.