IP Law Daily, PATENT—Fed. Cir.: Validity of Allergan's IBS-D treatment patents reinstated on appeal, (Aug 13, 2024)

By Saurabh Kashyap, B.A., LL.B., LL.M.

District court erred in its application of obviousness-type double patenting and written description standards.

The U.S. Court of Appeals for the Federal Circuit reversed a federal district court’s ruling in a patent infringement lawsuit between leading pharmaceutical companies and determined that certain patents held by the plaintiff Allergan USA, Inc. and its affiliates were neither invalid for obviousness-type double patenting (ODP) nor for lack of written description under 35 U.S.C. § 112. The Federal Circuit held that the district court’s reliance on later-expiring claims to invalidate earlier-expiring patents was misplaced and clarified the proper analysis for determining written description requirements (Allergan USA, Inc. v. MSN Laboratories Private Ltd., No. 24-1061 (Fed. Cir. Aug. 13, 2024)).

Background. The plaintiff/ appellant, Allergan USA, Inc., is a global pharmaceutical company known for developing and commercializing prescription medications across various therapeutic areas. It markets Viberzi®, a prescription medication for treating irritable bowel syndrome with diarrhea (IBS-D). The co-plaintiffs/co-appellants are Allergan’s group companies.

The defendant/appellee, MSN Laboratories Private Ltd., is based in India and specializes in developing and manufacturing active pharmaceutical ingredients (APIs) and finished dosage forms. The co-defendant/ appellee, MSN Pharmaceuticals, Inc., is a U.S.-based subsidiary of MSN Laboratories and focuses on commercializing and distributing these pharmaceutical products within the United States. The other co-defendant/appellee, Sun Pharmaceutical Industries Limited, is headquartered in India and is a significant player in the global generic drug market. It has a strategic partnership with MSN Laboratories.

The dispute centered around several patents related to the drug Eluxadoline, marketed by Allergan under the brand name Viberzi®. The asserted patents included 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). These patents cover the drug’s composition, formulations, and methods of use, particularly targeting IBS-D.

Sun Pharmaceutical Industries filed an Abbreviated New Drug Application (ANDA) seeking approval to market a generic version of Viberzi®. Allergan responded by suing Sun, asserting that Sun’s ANDA infringed the ‘356 patent under the Hatch-Waxman Act. As additional patents (’179, ’291, ’792, and ’516) covering Eluxadoline formulations were issued, Allergan amended its complaint to include these new patents, claiming infringement.

At trial, the district court ruled in favor of the defendants, holding that claim 40 of the ’356 patent was invalid for ODP over later-filed patents and that the asserted claims of the ’179, ’291, ’792, and ’516 patents lacked an adequate written description. The court’s ruling was based on the expiration dates of the patents, finding that the ’356 patent, despite being the first to file and issue, could be invalidated by the later-filed but earlier-expiring patents. Allergan appealed the district court’s decision.

Obviousness-type double patenting. The Federal Circuit disagreed with the district court’s ODP analysis, emphasizing that the ‘356 patent was the first to file and issue, covering the core invention of Eluxadoline. The court found that the district court’s approach, which considered only the expiration dates of the patents, was incorrect. The Federal Circuit clarified that a later-filed, later-issued, earlier-expiring patent within the same patent family cannot invalidate a first-filed, first-issued, later-expiring patent.

Referencing Novartis AG v. Ezra Ventures LLC, 909 F.3d 1367 (Fed. Cir. 2018), the appellate court emphasized that the primary purpose of ODP was to prevent the unjust extension of a patent’s exclusivity, which was not the case with the ’356 patent. In Ezra, the Federal Circuit had held that a later-expiring patent resulting from a patent term extension (PTE) under 35 U.S.C. § 156 could not be invalidated on ODP grounds by an earlier-expiring patent that did not receive such an extension.

The Federal Circuit concluded that the ’356 patent, the first patent in its family to file and issue, could not extend the exclusivity period improperly and, therefore, was not subject to ODP over the ’011 and ’709 patents. Thus, the Federal Circuit reversed the district court’s determination that claim 40 of the ’356 patent was invalid.

Written description requirement. Regarding the written description issue, the Federal Circuit reversed the district court’s finding that the asserted claims of the ’179, ’291, ’792, and ’516 patents were invalid for lack of written description. The district court had concluded that the patents did not adequately describe formulations without a glidant, an inert ingredient typically included in pharmaceutical tablets to aid in manufacturing. However, The Federal Circuit found that the patent specifications provided sufficient description, including examples of formulations both with and without a glidant.

The court pointed to its ruling in Ariad Pharmaceuticals, Inc. v. Eli Lilly & Co., 598 F.3d 1336 (Fed. Cir. 2010) (en banc), where it held that the written description requirement is met if the specification reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date. The Federal Circuit noted that the specifications in Allergan’s patents described the claimed formulations, including those that could exclude a glidant, thus satisfying the written description requirement. The appellate court also emphasized that a written description does not require a detailed explanation of every possible formulation variant but must demonstrate that the inventor was in possession of the claimed invention.

Moreover, the court acknowledged that while the specification primarily described formulations including a glidant, it did not exclude formulations without a glidant. Therefore, the claims that did not require a glidant were supported by the specification, reversing the district court’s judgment of invalidity under 35 U.S.C. § 112.

Judge Dyk’s partial dissent. Circuit Judge Timothy B. Dyk issued a separate opinion, concurring with the majority on the ODP issue but dissenting on the written description finding. Judge Dyk argued that the district court was correct in its analysis that the specification did not demonstrate possession of formulations without a glidant. He emphasized that the specification consistently described the necessity of a glidant for ensuring proper flow characteristics, and without explicit disclosure that a glidant was optional, the claims should not be upheld.

Judge Dyk referenced ICU Medical, Inc. v. Alaris Medical Systems, Inc., 558 F.3d 1368 (Fed. Cir. 2009), where the court held that claims to a “spikeless” medical valve were invalid for lack of written description because the specification uniformly described valves with spikes. He argued that similar reasoning applied in this case because the specification did not adequately disclose formulations without a glidant, making it impossible for a person of ordinary skill in the art to understand that the inventors possessed such formulations at the time of filing.

In Judge Dyk’s view, the majority’s opinion incorrectly expanded the written description requirement, potentially leading to broader claims than what was actually disclosed. Judge Dyk expressed concern that this approach could undermine the purpose of the written description requirement, which is to ensure that the patent applicant fully discloses the claimed invention, preventing overbroad patent claims that could stifle innovation.

The Case is No. 24-1061.

Judge: Lourie, A.

Attorneys: Eric William Dittmann (Paul Hastings LLP) for Allergan USA, Inc., Allergan Holdings Unlimited Co., Allergan Pharmaceuticals International Ltd., Janssen Pharmaceutica NV, and Eden Biodesign, LLC. Charles B. Klein (Winston & Strawn LLP) for Ronald M. Daignault (Daignault Iyer LLP) for MSN Laboratories Private Ltd., MSN Pharmaceuticals, Inc., and Sun Pharmaceutical Industries Limited.

Companies: Allergan USA, Inc.; Allergan Holdings Unlimited Co.; Allergan Pharmaceuticals International Ltd.; Janssen Pharmaceutica NV; Eden Biodesign, LLC. MSN Laboratories Private Ltd.; MSN Pharmaceuticals, Inc.; Sun Pharmaceutical Industries Limited

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