Wyeth LLC v. AstraZeneca Pharmaceuticals LP — Federal Circuit Affirms Invalidity of Cancer Drug Patents for Lack of Enablement

Background

Wyeth LLC owns two patents — U.S. Patent Nos. 10,603,314 and 10,596,162 — directed to methods of treating non-small cell lung cancer (NSCLC) that has become resistant to the drugs gefitinib and erlotinib. The patents claim methods of administering a daily “unit dosage” of an irreversible epidermal growth factor receptor (EGFR) inhibitor — a compound that permanently latches onto a specific part of the cancer cell receptor — to patients with this drug-resistant NSCLC.

In 2021, Wyeth sued AstraZeneca in the District of Delaware, alleging that AstraZeneca’s blockbuster cancer drug Tagrisso (osimertinib) infringed these patents by inducing physicians to use it in patients with drug-resistant NSCLC. After a five-day trial, the jury sided with Wyeth, finding the patents valid and infringed and awarding $107.5 million in damages. AstraZeneca then moved for judgment as a matter of law (JMOL), arguing no reasonable jury could have found the patents enabled the full scope of the claimed invention. The district court agreed and threw out the jury verdict, finding the patents invalid for lack of enablement. Wyeth appealed.

The core dispute on appeal was whether the patent specifications — their detailed written descriptions — adequately taught skilled researchers how to determine the correct daily dosage of an irreversible EGFR inhibitor to administer to a patient with drug-resistant NSCLC, across the full range of compounds the broad claims covered.

The Court’s Holding

The Federal Circuit, in an opinion by Judge Lourie joined by Judges Linn and Hughes, affirmed the district court in all respects. The court rejected Wyeth’s argument that the claims only required a compound capable of killing cancer cells in a test tube, finding instead that the plain language of the claims demanded actual daily administration of a “unit dosage” to a human patient — a dosing regimen that produces a therapeutic effect in a living person, not merely in vitro results.

On the enablement question, the court found substantial evidence supported JMOL of invalidity. The specifications disclosed no working examples of dosages actually administered to patients; the dosage ranges they provided (1–1,000 mg generally; 2–500 mg preferred) were so broad that some fell at toxic or lethal levels for the disclosed compounds — a fact Wyeth’s own trial experts essentially conceded. The court emphasized that the specification itself acknowledged that determining the right dose “depends on the subject to be treated” and the “judgment of the practitioner,” yet provided no guidance on how to navigate that complexity across the wide class of compounds claimed. Citing Amgen Inc. v. Sanofi, 598 U.S. 594 (2023), the court reiterated that “the more one claims, the more one must enable.” Here, Wyeth claimed a functionally-defined class of irreversible EGFR inhibitors but enabled only a starting point for further research — precisely the kind of incomplete disclosure the enablement doctrine prohibits.

The Federal Circuit also rejected Wyeth’s contention that the district court improperly shifted its claim construction post-verdict to add clinical safety requirements. The court found the district court consistently construed “unit dosage” to require a therapeutically effective dose in a patient — neither more (full FDA approval) nor less (any dose capable of killing cancer cells in a dish).

Key Takeaways

• Broad functional claims need broad enablement. Claiming an entire class of compounds based on shared function (irreversible EGFR inhibition) requires the specification to enable the full scope — including showing how to identify workable dosages across that class. A starting point plus general guidance is not enough when the art is unpredictable.
• “Unit dosage” in a method-of-treatment claim requires patient-level administrability. The court held that claiming daily administration of a unit dosage to a patient means the patent must enable determination of a dose that is therapeutically effective — and safe enough — for actual human use, not just in vitro efficacy.
• $107.5 million jury verdict erased. This case illustrates the power of JMOL post-verdict to correct jury findings when the enablement evidence is overwhelming — AstraZeneca successfully overturned a large damages award by proving by clear and convincing evidence that the patents should never have issued.
• Amgen v. Sanofi continues to reshape pharma patent litigation. The court’s reasoning tracks the Supreme Court’s 2023 landmark enablement decision, signaling that broadly functional pharmaceutical patents remain vulnerable, particularly when specifications lack dosing data for actual patient use.

Why It Matters

Tagrisso is one of AstraZeneca’s most important cancer drugs, generating billions in annual revenue. This ruling ends Wyeth’s claim to a share of that revenue and, more broadly, reinforces a demanding post-Amgen enablement standard for pharmaceutical method-of-treatment patents that claim wide functional classes of compounds. Drug companies and patent practitioners need to ensure that cancer treatment patents include not just in vitro data but dosing information translatable to patients across the full claimed compound class — or risk invalidity regardless of how successful the accused product turns out to be.

The decision also serves as a reminder of the JMOL mechanism’s power. Even after a multi-million-dollar jury verdict, a well-supported post-trial motion can overturn the result entirely, without a retrial, when the patent’s written description simply cannot sustain the legal requirements of enablement.