On September 18, 2024, the U.S. Court of Appeals for the Federal Circuit criticized the U.S. District Court for the District of Delaware for overstepping its authority in invalidating claims under 35 U.S.C. § 101. The claims involve Myrbetriq®, a Food and Drug Administration-approved extended-release formulation of mirabegron developed by Astellas Pharma to treat overactive bladder.  

Myrbetriq’s extended-release formulation, which addresses the issue of the drug’s changing effectiveness based on whether or not the patient has eaten, is protected under U.S. Patent No. 10,842,780 (the ‘780 patent). 

Several companies, including Sandoz and Lupin, sought to produce generic versions of Myrbetriq. To do so, they challenged Astellas Pharma’s patent, arguing it was invalid under several sections of the U.S. patent law. Consequently, the district court invalidated the said patent under 35 U.S.C. § 101. The court found that it did not meet patentability criteria, determining that its concept was the application of “previously known formulation technology” to address the food effect. 

However, the Federal Circuit reversed and remanded the case, reprimanding the district court for “rendering its decision on a ground not raised by any party at any stage of the proceedings.” While acknowledging the flexibility in the principle of party presentation, the appellate court found that invalidating a patent on grounds not raised by either party went too far. 

Moreover, the Federal Circuit clarified that patent eligibility under 35 U.S.C. § 101 is not a “threshold inquiry” akin to subject matter jurisdiction, noting that the presumption of validity applies to all grounds of validity, including § 101. Thus, the appellate court dismissed the defendants’ argument, highlighting that concerns around the invalidation of “pharmaceutical patents that delay low-cost generics” are irrelevant to the scope of the court’s authority. 

Astellas Pharma also raised concerns over the district court judge’s remarks about the pharmaceutical industry and requested to reassign the case. The remarks implied that brand and generic manufacturers were colluding to exploit the Hatch-Waxman amendments and that the U.S. Patent and Trademark Office had been lenient in granting patents for extended-release formulations. However, the Federal Circuit denied the request as the remarks were irrelevant to the appeal. The appellate court also noted that the case was not the right place for these frustrations and expressed confidence that the district court would approach the case objectively upon remand. 

The case, filed under 35 U.S.C. § 271(e)(2)(A), returned to the District of Delaware for further proceedings, where the district court is expected to reconsider the validity of the ‘780 patent based on the original arguments without introducing new legal grounds. 

This ruling is significant not only for Astellas Pharma but also for the broader pharmaceutical industry as it reaffirms the limits of judicial discretion in patent cases, particularly in the context of generic drug approvals. 

This case reflects ongoing debates in the pharmaceutical sector over patent eligibility, especially as companies seek to protect complex drug formulations. Courts are often asked to balance the need to incentivize innovation against concerns that overly broad patent claims might stifle competition. Extended-release formulations are often subject to challenges because they may involve known compounds or natural biological processes, making it harder to prove they meet the threshold for patentable subject matter under current law. 

- Cathy Li