Astellas Pharma, Inc. v. Sandoz Inc
Authored by: Jeremy J. Gustrowsky
In a recent decision, the Federal Circuit vacated a district court ruling that had invalidated key claims of Astellas Pharma’s patent for its overactive bladder drug, Myrbetriq® (U.S. Patent No. 10,842,780), on the grounds of patent ineligibility under Section 101—a defense that was never actually raised by the opposing parties. The case centered on Astellas’s sustained-release formulation of mirabegron, which was developed to address problematic “food effects” that affected how the drug was absorbed depending on whether it was taken with or without food.
During the litigation, the generic drug companies (including Sandoz Inc., Zydus Pharmaceuticals, and others) only challenged the patent’s validity under other grounds, specifically Sections 102, 103, and 112, and eventually narrowed their arguments to Section 112 issues alone. Neither side ever argued that the patent was invalid under Section 101, which deals with subject matter eligibility. Despite this, the district court judge took it upon himself to invalidate the patent claims under Section 101, reasoning that the invention was just an application of a natural law using conventional methods.
The Federal Circuit found this to be a clear abuse of discretion, emphasizing that courts must act as neutral arbiters and decide cases based on the issues presented by the parties, not on grounds the court raises on its own. The court highlighted the importance of the “party presentation principle,” which ensures that each side frames the dispute and that the burden of proving invalidity remains with the party asserting it. The court also clarified that the presumption of validity applies to all grounds of patent validity, including Section 101.
Although Astellas requested that the case be reassigned to a different judge due to concerns about impartiality, the Federal Circuit declined, stating that adverse rulings alone do not prove bias. The case was sent back to the district court for further proceedings—this time, limited to the actual issues the parties had raised. This decision reinforces the boundaries of judicial authority in patent cases and the importance of letting the parties, not the court, define the scope of the dispute.