AstraZeneca has secured a significant legal victory after a U.S. federal appeals court upheld a decision invalidating two patents asserted by Pfizer subsidiary Wyeth in a dispute over the blockbuster lung cancer treatment Tagrisso.
The U.S. Court of Appeals for the Federal Circuit affirmed a Delaware federal court’s ruling that the patents at the center of the case were not legally valid, effectively bringing an end to Wyeth’s infringement claims against the British drugmaker.
The dispute traces back to 2021, when Wyeth—acquired by Pfizer in 2009—filed suit alleging that Tagrisso infringed patents connected to the breast cancer drug Nerlynx, which is marketed by Puma Biotechnology under a licensing arrangement involving Pfizer’s intellectual property.
Although Wyeth initially prevailed at trial in 2024, winning a jury award of $107.5 million, that outcome did not stand. The trial judge later overturned the verdict after determining the patents failed to meet key legal standards. The court concluded the patent specifications did not adequately describe the claimed inventions and lacked sufficient technical detail to allow a skilled researcher to reproduce them without excessive experimentation.
The Federal Circuit agreed with that assessment, ruling that the patents were invalid because they did not satisfy the written description and enablement requirements under U.S. patent law. With those patents deemed invalid, AstraZeneca cannot be held liable for infringement based on them.
AstraZeneca declined to comment on the appellate ruling, while Pfizer did not immediately issue a public response.
The decision is a major boost for AstraZeneca, whose Tagrisso remains one of its most valuable medicines. The lung cancer therapy generated more than $7.2 billion in worldwide sales last year, making it one of the company’s top-performing products.
The case, Wyeth LLC v. AstraZeneca Pharmaceuticals LP, was heard by the U.S. Court of Appeals for the Federal Circuit under case number 24-2325. The ruling leaves intact the lower court’s decision that erased the earlier jury award in Wyeth’s favor.
