On May 23, 2018, Federal Circuit affirmed a Delaware court’s finding that a UCB Inc’s patent on the epilepsy drug Vimpat® is not invalid for double patenting or obviousness or anticipation.
This case arises under the Hatch-Waxman Act. UCB holds NDA that cover its lacosamide anti-epileptic drug approved by USFDA and marketed under the tradename Vimpat®. Appellants are generic drug manufacturers who filed Abbreviated New Drug Applications (“ANDAs”), seeking approval for generic versions of Vimpat® before expiration of U.S. Patent No. RE38,551. The ’551 patent covers lacosamide compound. As disclosed in the ’551 patent, lacosamide is the R-enantiomer of N-benzyl-2-acetamido-3-methoxypropionamide. The specification teaches that “the R stereoisomer is unexpectedly more potent than the corresponding S stereoisomer and the racemic mixture.” The claims of the ’551 patent at issue in this case are dependent claims 9, 10, and 13.Claim 9 covers (R) N-Benzyl 2-Acetamido-3-methoxypropionamide containing at least 90% (w/w) R stereoisomer. Claim 10 covers therapeutic composition & claim 13 covers method of treating human.
Before the district court, Appellants asserted that claims 9, 10, and 13 of the ’551 patent are invalid for obviousness-type double patenting, alleging that they are not patentably distinct from claims 44–47 of the U.S. Patent No. 5,654,301 (continuation-in-part of the 5,378,729). Appellants also argued that the compound described in the asserted claims of the ’551 patent is merely an obvious species of the genus claimed in the ’301 patent. Following a bench trial, the district court found that it would not have been obvious to a person of ordinary skill in the art to make lacosamide by placing an unsubstituted benzyl at R or an unsubstituted methyl at R1 in combination with methoxymethyl at R3. Appellants also asserted that LeGall’s disclosure of the racemic mixture compound 107e alone, or in combination with the ’729 patent’s disclosure of the genus and Kohn 1991’s disclosure of compound 3l rendered the asserted claims of the ’551 patent obvious. The district court applied a lead compound analysis and concluded that, as of March 1996, a skilled artisan would not have selected any Functionalized Amino Acid (FAA) genus, let alone compound 107e (LeGall) or compound 3l (Kohn 1991), as a lead compound. Finally, Appellants asserted that the ’551 patent was anticipated by LeGall’s disclosure of the racemic mixture of compound 107e, which necessarily discloses the enantiomers of that mixture, including the R enantiomer. The district court held that LeGall does not anticipate the asserted claims because, while it discloses the racemic mixture compound 107e, it does not explicitly disclose the R-enantiomer or its characteristics. Thus, district court made exhaustive fact findings based on the trial evidence and concluded that the asserted claims (9, 10, and 13) of the ’551 patent are not invalid. Appellants appealed.
Obviousness-type double patenting:
Appellants asserted that claims 9, 10, and 13 of the ’551 patent are not patentably distinct from claims 44–47 of the ’301 patent and are thus invalid for obviousness-type double patenting. Because these claims only have a common methoxymethyl group at the R3 position, the question before court was whether a person of ordinary skill in the art, starting with claim 45 of the ’301 patent, would have been motivated to place an unsubstituted benzyl at R and an unsubstituted methyl at R1 in combination with the methoxymethyl group at R3 with a reasonable expectation of success.