The U.S. Court of Appeals for the Federal Circuit recently affirmed a district court’s finding of invalidity based for double-patenting and held that a claim to an active pharmaceutical ingredient is invalidated by an earlier claim to a three-element composition that included the active compound. In re Metoprolol Succinate Patent Litig., Case No. 06-1254 (Fed. Cir., July 23, 2007) (Gajarsa, J.; Schall, J. dissenting-in-part).
Generic drug companies applied to the U.S. Food and Drug Administration (FDA) for approval to market generic versions of Toprol-XL, a branded cardiovascular drug containing extended-release metoprolol succinate. The generic applicants made Paragraph IV certifications under the Hatch-Waxman Act that AstraZeneca’s patents listed in the FDA’s Orange Book for Toprol-XL (the ’161 and ’154 patents) were invalid or not infringed by the proposed generic products. AstraZeneca sued the generics for patent infringement. The district court granted summary judgment of invalidity for obviousness-type double patenting on both patents. Obviousness-type double patenting is a judicially created doctrine adopted to prevent claims in separate applications or patents that do not recite the same invention, but nonetheless claim inventions so alike that granting both exclusive rights would effectively extend the life of patent protection. Astra appealed the grant of summary judgment for invalidity of the ’154 patent.
The earlier claim at issue was to an oral pharmaceutical composition that had a core containing "metoprolol succinate" (or one of 10 other active ingredients) with a surrounding inner coating that allowed gradual release and an outer coating that was designed to stay intact until the pill reached the lower digestive tract. The later claim in the ’154 patent was to "metoprolol succinate." On appeal, the Federal Circuit noted that its 1997 In re Emert decision, which presented closely analogous facts, mandated a finding of invalidity. The panel majority observed that "in this case, Claim 1 of the ’154 patent claiming a compound (A1) is an obvious variation of Claim 8 of the ’318 patent claiming a composition comprised of one compound of an enumerated list (A1, A2, A3, etc.), an inner layer (B), and an outer layer (C)," and therefore that "it would have been an obvious variation of Claim 8 of the ’318 patent to omit the inner layer (B) and the outer layer (C)." Citing the Supreme Court’s decision in KSR, the Federal Circuit also noted that the omission of the known elements from the composition in this case was the product of ordinary skill and common sense rather than of innovation.
Judge Shall’s dissent argued that the claim to the three-element composition A-B-C is, under the law, patentably distinct from a claim to A alone, and that the majority’s holding prevents the issuance of a later claim to an active ingredient when the active ingredient has been patented and marketed as part of a composition.
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