Allergan USA, Inc. v. MSN Labs. Private Ltd.

Case Name: Allergan USA, Inc. v. MSN Labs. Private Ltd., 111 F.4th 1358, 2024 WL 3763599 (Fed. Cir. Aug. 13, 2024) (Circuit Judges Lourie, Dyk, and Reyna presiding; Opinion by Lourie, J.; Opinion concurring-in-part and dissenting-in-part by Dyk, J.) (Appeal from D. Del., Andrews, J.) 

Drug Product and Patent(s)-in-Suit: Viberzi® (eluxadoline); U.S. Patent Nos. 7,741,356 (“the ’356 patent”), 11,007,179 (“the ’179 patent”), 11,090,291 (“the ’291 patent”), 11,160,792 (“the ’792 patent”), and 11,311,516 (“the ’516 patent”)

Nature of the Case and Issue(s) Presented: FDA approved Viberzi, which mitigates the symptoms of irritable bowel syndrome with diarrhea (“IBS-D”), in 2015. The ’356 patent claims the eluxadoline compound and expires on June 24, 2026. U.S. Patent Nos. 8,344,011 (“the ’011 patent”) and 8,609,709 (“the ’709 patent”) issued from continuation applications that claim priority to the filing date of the ’356 patent. The ’011 patent issued on Jan. 1, 2013, expires on Mar. 14, 2025, and claims a method for treating a gastrointestinal disorder by administering eluxadoline or one of seven other compounds. The ’709 patent issued on Dec. 17, 2013, also expires on Mar. 14, 2025, is subject to a terminal disclaimer over the ’356 patent, and claims the eluxadoline compound. Each of the ’179, ’291, ’792, and ’516 patents, which share a common specification, claim formulations of eluxadoline.

In October 2020, Allergan sued Sun alleging patent infringement of the ’356 patent. In May 2021, Allegan filed a new complaint alleging patent infringement of the ’179 patent. Issuance of each of the ’291 patent, the ’792 patent, and the ’516 patent soon followed, and with each issuance Allergan amended its complaint to add new claims of infringement. Following discovery and ahead of trial, the parties stipulated that Sun would infringe all the asserted claims if those claims were valid. The only issues before the district court at trial were: (i) whether the ’356 patent was invalid for obviousness-type double patenting (“ODP”); and (ii) whether the ’179, ’291, ’792, and ’516 patents were invalid for lack of written description. The district court found all asserted claims invalid. On appeal, the Federal Circuit reversed.

Why Allergan Prevailed: Relying on Federal Circuit precedent, the district court held that because the ’356 patent expired after the reference claims of the ’011 and ’709 patents due to PTA, it was invalid for ODP. The Federal Circuit extensively distinguished the precedential case relied on by the district court:

The problem with that result, however, is that Cellect answered a different question than that at issue here. Our holding in Cellect is only controlling in this case to the extent that it requires us to consider, in our ODP analysis, the ’356 patent’s June 24, 2026 expiration date (i.e., the expiration date after the addition of PTA), not the March 24, 2025 expiration date that it would have shared with the ’011 and ’709 reference patents in the absence of a PTA award. It does not follow, however, that the ’356 patent must be invalidated by the ’011 and ’709 reference patents simply because it expires later. Indeed, Cellect does not address, let alone resolve, any variation of the question presented here—namely, under what circumstances can a claim properly serve as an ODP reference—and therefore has little to say on the precise issue before us.

The Federal Circuit concluded that the claims of the ’011 and ’709 patents were not proper ODP references that can be used to invalidate the ’356 patent. The ’356 patent is undoubtedly the “first” patent to cover eluxadoline, and each of the ’011 and ’709 patents is unquestionably “second” to that patent. Each of the ’011 and ’709 patents claims priority from the application that led to the ’356 patent. A first-filed, first-issued, later-expiring claim cannot be invalidated by a later-filed, later-issued, earlier-expiring reference claim having a common priority date. Therefore, the ’356 patent is not invalid for ODP over the ’011 patent or the ’709 patent.

With regard to the issue of written description, the Federal Circuit acknowledged that “this is not a typical written description case.” The asserted claims are narrow picture claims to a particular pharmaceutical tablet comprising eluxadoline and various excipients. The claims recite specific amounts of the excipients, not ranges in the amount or types of classes of excipients. The issue is “whether the inventors had possession of a formulation that lacked a component that is not claimed, or only optional. In the district court's view, they did not. We disagree.”

The district court determined that the common specification of ’179, ’291, ’792, and ’516 patents disclosed only a narrow group of eluxadoline formulations, all of which include a glidant. It further found no indication that a glidant was not required to practice the invention. The Federal Circuit found the district courts findings to be clear error. The specification described embodiments requiring only eluxadoline and some other ingredient, not necessarily a glidant. Moreover, the originally filed patent application claims recited formulations without a glidant. “It therefore cannot be, as the district court found, that the inventors did not have possession of a formulation in which a glidant was not required.”

Judge Dyk filed an opinion dissenting with the majority’s opinion concerning written description. Relying on unrebutted expert testimony that a skilled artisan would normally use a glidant and that, absent a teaching to the contrary, he would interpret the specification to show that the inventor possessed only formulations that include a glidant, he would have affirmed the district court’s opinions concerning written description.