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Inherent Feature in Prior Art Was Anticipating, Even Though Not Previously Appreciated

November 10, 2006

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Last Month at the Federal Circuit - December 2006

Judges: Bryson, Archer, Gajarsa (author)

[Appealed from: N.D. Ill., Judge Guzman]

In Abbott Laboratories v. Baxter Pharmaceutical Products, Inc., Nos. 06-1021, -1022, -1034 (Fed. Cir. Nov. 9, 2006), the Federal Circuit reversed the district court’s judgment that the claims of U.S. Patent No. 5,990,176 (“the ’176 patent”) were valid.

Abbott Laboratories and Central Glass Company, Ltd. (collectively “Abbott”) are the owners of the ’176 patent, which involves a degradation-prevention combination of water or other “Lewis acid inhibitors” with sevoflurane. Abbott discovered that water mixed in with sevoflurane will deactivate and bind to Lewis acids, therefore protecting sevoflurane against degradation reaction. Baxter Pharmaceutical Products, Inc. and Baxter Healthcare Corporation (collectively “Baxter”) also had its own sevoflurane product and filed a certification of invalidation and noninfringement of the ’176 patent with the FDA. Abbott then sued Baxter for infringement of the ’176 patent. After a bench trial, the district court held that the asserted claims were valid and enforceable but not infringed.

On appeal, the Federal Circuit considered Baxter’s argument that prior art U.S. Patent No. 5,684,211 (“the ’211 patent”) disclosed a composition of watersaturated sevoflurane and, therefore, anticipated the ’176 patent. According to the Court, at the time of the ’176 patent, knowledge of the beneficial nature of a water-sevoflurane mix was not known. The ’211 patent discloses a composition and the claims are directed to a process for making that composition. The ’211 patent, however, does not teach the advantageous feature of that composition.

The Federal Circuit explained that “[o]ur cases have consistently held that a reference may anticipate even when the relevant properties of the thing disclosed were not appreciated at the time.” Slip op. at 7. “The general principle that a newly-discovered property of the prior art cannot support a patent on the same art is not avoided if the patentee explicitly claims that property.” Id. at 8. Moreover, a prior art reference may anticipate without disclosing a feature of the claimed invention if that missing characteristic is necessarily present, or inherent, in the single anticipating reference. Abbott argued that at the time of the ’211 patent, nobody knew that the watersaturated sevoflurane that the patent disclosed had the property of resisting the Lewis acid degradation. But in the Court’s view, the “lack of knowledge is wholly irrelevant to the question of whether the ’176 patent claims something ‘new’ over the disclosure of the ’211 patent,” because the claimed property of resistance to degradation is found “inherently” in the disclosure. Id.

The Federal Circuit rejected the district court’s reliance on Bristol-Myers Squibb Co. v. Ben Venue Labs, Inc., 246 F.3d 1368 (Fed. Cir. 2001), which held that new uses of known processes may be patentable. As a threshold matter, the Court noted that the proposition only applied to process claims and thus should not have been applied to those claims of the ’176 patent directed to a composition. As to the process claims, the Court found that the claimed process in the ’176 patent was not directed to a new use—it was the same use. Specifically, both the ’176 and ’211 patents disclosed methods to guarantee sevoflurane will be of high purity at the time it is dispensed to patients. The Court found that each step in the ’176 patent is disclosed in the ’211 patent, and for the same purpose, namely the delivery of safe, effective sevoflurane anesthetic. Thus, the Court reversed the district court’s judgment that the asserted claims were valid.