Introduction
The litigation between Allergan USA, Inc. and Sun Pharmaceutical Industries Ltd. is a complex and multifaceted case involving patent infringement, validity, and various affirmative defenses. This summary will delve into the key aspects of the case, including the procedural history, the patents in suit, the court's rulings, and the implications of these decisions.
Procedural History
The case began in September 2019 when Allergan filed a complaint against Sun Pharmaceutical Industries Ltd. in the US District Court for the District of Delaware. Allergan alleged that Sun's filing of an Abbreviated New Drug Application (ANDA) for a generic version of Allergan's eluxadoline tablet, Viberzi, infringed several of Allergan's patents[2][3].
Initial Complaint and Patents in Suit
Allergan initially asserted infringement of U.S. Patent Nos. 9,675,587 and 10,188,632. Over the course of the litigation, Allergan filed continuation applications and obtained additional patents, including U.S. Patent Nos. 11,007,179, 11,090,291, 11,160,792, 11,229,627, and 11,311,516, which were also asserted against Sun[3][5].
District Court Rulings
Obviousness-Type Double Patenting (ODP)
The district court found claim 40 of the '356 patent invalid under the doctrine of obviousness-type double patenting (ODP). Allergan argued that this claim should not be subject to ODP because it was the first patent claiming eluxadoline to have been filed, despite the later filing and issuance dates of its child patents. The court rejected this argument, focusing on the expiration dates of the patents rather than the filing dates[1].
Lack of Written Description
Certain claims of the '179, '291, '792, and '516 patents were found invalid for lack of written description. The court determined that the specification did not support the optional use of a glidant (e.g., colloidal silica) in the pharmaceutical tablet formulations[1].
Affirmative Defenses and Counterclaims
Unclean Hands Counterclaim
Sun Pharmaceutical alleged an unclean hands counterclaim and affirmative defenses, including prosecution history estoppel, judicial estoppel, waiver, estoppel, laches, and patent misuse. Sun claimed that Allergan misused Sun's confidential information to prosecute the '516 patent and assert it against Sun. However, Sun later stipulated that it would not introduce evidence of Allergan misusing confidential information, which undermined its unclean hands counterclaim. The court granted Allergan's motion for judgment on the pleadings regarding the unclean hands counterclaim but denied it for other affirmative defenses[3][5].
Public Information and Patent Strategy
The court ruled that using public information to shape patent strategy, including drafting claims, does not constitute misuse of confidential information or unconscionable conduct. This decision emphasized that there is nothing inherently wrong with using public information to inform patent strategy[3].
Appeal and Federal Circuit Rulings
Reversal of Invalidity Determinations
Allergan appealed the invalidity determinations to the Federal Circuit. The Federal Circuit reversed the district court's judgment, finding that the pharmaceutical formulation claims in the patents were not invalid. The court split on the issues of written description and proclaimed a new exception to the ODP doctrine[1][4].
Key Takeaways
- Filing Dates vs. Expiration Dates: The Federal Circuit emphasized the importance of filing dates over expiration dates in determining obviousness-type double patenting.
- Written Description Requirement: The court strictly enforced the written description requirement, invalidating claims that lacked specific support in the patent specification.
- Use of Public Information: The court clarified that using public information to inform patent strategy is permissible and does not constitute misconduct.
- Affirmative Defenses: The case highlights the challenges in asserting affirmative defenses such as unclean hands, prosecution history estoppel, and patent misuse, particularly when the underlying allegations are not supported by evidence.
FAQs
What was the main issue in the Allergan v. Sun Pharmaceutical case?
The main issue was whether Sun Pharmaceutical's generic version of Allergan's eluxadoline tablet infringed Allergan's patents and whether those patents were valid.
What is obviousness-type double patenting (ODP)?
ODP is a doctrine that prevents the extension of patent term by filing multiple patents on the same invention, ensuring that the patent term does not exceed the statutory limit.
Why were some of Allergan's patent claims found invalid?
Some claims were found invalid due to lack of written description in the patent specification and others due to obviousness-type double patenting.
What was the outcome of Sun's unclean hands counterclaim?
Sun's unclean hands counterclaim was dismissed because Sun stipulated that it would not introduce evidence of Allergan misusing confidential information, undermining its allegations.
How did the Federal Circuit rule on the appeal?
The Federal Circuit reversed the district court's invalidity determinations, finding that the pharmaceutical formulation claims were not invalid and establishing a new exception to the ODP doctrine.
Cited Sources:
- Federal Circuit Reverses Allergan Patent Invalidity Rulings - National Law Review
- Allergan USA, Inc. et al v. Sun Pharmaceutical Industries Ltd. - Justia Dockets
- Allergan USA, Inc. v. Sun Pharm. Indus. Ltd. - Robins Kaplan LLP
- United States Court of Appeals for the Federal Circuit - Patently-O
- Allergan U.S. Inc. v. Sun Pharm. Indus., 636 F. Supp. 3d 483 - Casetext
