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

Viberzi® (eluxadoline)

September 27, 2023

GENERICally Speaking

Case Name: Allergan USA, Inc. v. MSN Labs. Private Ltd., C.A. Nos. 19-1727-RGA, 20-1479-RGA, 2023 WL 6295496 (D. Del. Sept. 27, 2023) (Andrews, J.)

Drug Product and Patent(s)-in-Suit: Viberzi® (eluxadoline); U.S. Patents Nos. 11,007,179 (“the ’179 patent”), 11,090,291 (“the ’291 patent”), 11,160,792 (“the ’792 patent”), 11,311,516 (“the ’516 patent”), 7,741,356 (“the ’356 patent”), and 11,229,627 (“the ’627 patent”)

Nature of the Case and Issue(s) Presented: Allergan holds the NDA for Viberzi, which is FDA approved for treating irritable bowel syndrome with diarrhea (“IBS-D”) in adults. Defendants submitted ANDAs seeking FDA approval to make and sell generic versions of that drug. Allergan filed complaints against MSN and Sun alleging infringement of earlier issued Orange Book-listed patents. As the cases progressed, the patents-in-suit issued and were also asserted against Defendants. Allergan and Sun stipulated that Sun would infringe the asserted claims of the ’179, ’291, ’792, ’516, and ’356 patents if the claims were found valid. At trial, the only issues between Allergan and Sun were whether the asserted claims of the ’179, ’291, ’792, ’516, and ’356 patents are invalid. Sun argued the asserted claims of the ’179, ’291, ’792, and ’516 patents were invalid for lack of written description. If the court found that those asserted claims were sufficiently described, then Sun argued those claims would be invalid as obvious. Sun also argued that the asserted claim of the ’356 patent was invalid for obviousness-type double patenting. At trial, the only issues between Allergan and MSN were whether the asserted claims of the ’627 and ’291 patents were invalid for lack of written description and non-enabled. If the court found adequate written description and enablement, then, according to MSN, the claims would be invalid as obvious. After a three-day bench trial, the court found the asserted claims of the ’627, ’291, ’179, ’792, and ’516 patents invalid for lack of written description and the asserted claim of the ’356 patent invalid for obviousness-type double patenting (“ODP”).

Why Defendants Prevailed: Sun’s written description defense. A glidant is an agent that is used to improve the flow characteristics of a powder mixture. Sun argued that the shared specification does not adequately describe a pharmaceutical formulation that does not require a glidant. Put another way, Sun contended that because the specification only discloses formulations that contain a glidant and “nothing in the specification describes, or even suggests, that the inventors possessed a formulation without a glidant,” the claims are invalid for lack of written description. The court agreed. “For all the formulations disclosed in the patent specification, a glidant is used without any indication that it was not required to practice the invention. For example, there is nothing to signal to a POSA that without a glidant the formulations would have sufficient flow characteristics. Of course, patents are not limited to the specific embodiments disclosed in the specification. But the specification here fails to show that the patentee was in possession of a formulation in which the inclusion of the glidant was optional.”

MSN’s written description defense. The shared specification of the patents-in-suit incorporates by reference a prior art reference, Breslin, and the parties dispute the scope of incorporation. MSN argued that, based on the context in which Breslin is cited in the specification, a POSA would understand Breslin to be incorporated only for its discussion about how eluxadoline can be used to treat gastrointestinal disorders along with the identification of the eluxadoline molecule and its mechanism of action. Allergan argued that the excerpted portion of Breslin is incorporated into the patent specification because the specification states that Breslin is incorporated in its entirety, and the court agreed.

The asserted claims against MSN cover formulations of eluxadoline that use any “filler” and any “disintegrant” at specific amounts or weight percentages. The specification only disclosed formulations made with the same disintegrant (crospovidone) and fillers (mannitol and SMCC). “The specification is explicit about using these specific excipients, not functional groups, as it repeatedly recites using SMCC and crospovidone.” When referring to glidants, the patentee referred to the common functional category, “glidant,” and then provided colloidal silica as a preferred embodiment. “In contrast to glidant, the patentee did not use a similar descriptive framework for filler and disintegrant (e.g., listing ‘disintegrant’ and then providing crospovidone as a preferred embodiment).” Therefore, a POSA would read the specification to only disclose a formulation with SMCC and crospovidone, not a formulation using any filler and any disintegrant. Allergan’s argument that Breslin gives examples of fillers and disintegrants, while true, is misplaced. “That Breslin gives multiple examples of fillers and disintegrants, however, does not mean it gives multiple examples of the claimed species (i.e., the combinations of fillers and disintegrants that can be used to make formulations of eluxadoline).”

Sun’s ’356 patent ODP defense. The issue here was whether the fact the ’356 patent expires after the ’011 and ’709 patents makes it invalid for obviousness-type double patenting over those two patents. Claim 40 of the ’356 patent is not patentably distinct from the asserted claims of the ’011 and ’709 patents. The expiration date of the ’356 patent, after addition of PTA, falls after the expiration dates of the ’011 and ’709 patents. ODP therefore invalidates the challenged claim.

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