IP Law Daily, PATENT—Fed. Cir.: AstraZeneca preserves invalidation of lung cancer treatment patents on appeal, (Jul 10, 2026)

By Ravindra Kumar Singh, B.L.

The patent specification failed to enable the claimed treatment methods because it did not teach skilled artisans how to determine therapeutic daily dosages without undue experimentation.

The U.S. Court of Appeals for the Federal Circuit has affirmed a federal district court's judgment as a matter of law invalidating patents covering methods of treating drug-resistant non-small cell lung cancer (NSCLC). The court held that the patents failed the enablement requirement of 35 U.S.C. § 112 because, although they broadly claimed daily administration of irreversible EGFR inhibitors to treat resistant NSCLC, they did not teach skilled artisans how to determine therapeutically effective unit dosages across the full scope of the claimed compounds without undue experimentation. As a result, the court upheld the post-verdict invalidation of the patents and left undisturbed a jury's $107.5 million infringement award that the district court had set aside (Wyeth LLC v. Astrazeneca Pharmaceuticals LP, No. 24-2325 (Fed. Cir. Jul. 9, 2026)).

Background. The plaintiff-appellant, Wyeth LLC, is a pharmaceutical company that develops prescription medicines, including cancer therapies. The defendants-appellees, AstraZeneca Pharmaceuticals LP and AstraZeneca AB, develop and market pharmaceutical products, including Tagrisso® (osimertinib), a treatment for EGFR-mutated non-small cell lung cancer.

The dispute involved U.S. Patent Nos. 10,603,314 (the ’314 patent) and 10,596,162 (the ’162 patent). The patents generally relate to methods of treating gefitinib- and erlotinib-resistant NSCLC by administering irreversible epidermal growth factor receptor (EGFR) inhibitors that covalently bind to specific cysteine residues within EGFR or erb-B2. The patents sought to overcome resistance that often develops to earlier reversible EGFR inhibitors by using irreversible inhibitors that provide longer-lasting inhibition of cancer cell growth.

Wyeth sued AstraZeneca in the District of Delaware in 2021, alleging that AstraZeneca induced infringement of the asserted patents by marketing and selling Tagrisso. Before trial, the district court construed the claim term "unit dosage" as "physically discrete units suitable as unitary dosage for the subject, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect." Following a five-day jury trial, the jury found the asserted claims valid and infringed and awarded Wyeth $107.5 million in damages. The district court subsequently granted AstraZeneca's renewed motion for judgment as a matter of law (JMOL), holding the asserted claims invalid for lack of enablement, and set aside the jury's $107.5 million infringement award. Wyeth appealed.

Claim construction. Wyeth first argued that the district court effectively changed its construction of "unit dosage" after trial by importing unclaimed clinical safety and efficacy requirements into the claims.

The Federal Circuit disagreed. It explained that the district court had consistently construed "unit dosage" according to the patent's own express definition and merely clarified what was already inherent in that construction. The claims required daily administration of a unit dosage to a human patient to produce a therapeutic effect, not merely identification of compounds capable of killing cancer cells in laboratory testing.

The court emphasized that this interpretation did not import FDA approval standards or clinical efficacy requirements into the claims. Rather, it simply gave effect to the claim language requiring daily administration of a therapeutically effective unit dosage to a patient. Citing Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc), the court reiterated that claim terms must be interpreted in light of the specification, while Merck & Co. v. Teva Pharmaceuticals USA, Inc., 395 F.3d 1364 (Fed. Cir. 2005), supported construing claims so that every limitation has operative meaning.

Enablement. The Federal Circuit next addressed whether the patents enabled the full scope of the claimed invention. It explained that the specification identified only three example irreversible EGFR inhibitors and disclosed only laboratory (in vitro) testing. It contained no working examples showing therapeutically effective daily dosages administered to human patients. It did not explain how skilled artisans could translate the laboratory results into clinically usable dosing regimens.

Although the patents disclosed broad dosage ranges, they provided no guidance on how those ranges were derived, how to select appropriate doses for particular compounds, or how to determine whether the disclosed dosages would produce the claimed therapeutic effect in patients. Instead, the specification simply stated that a skilled artisan would know the effective dose for each patient.

The court held that such disclosure was insufficient. Relying on Amgen Inc. v. Sanofi, 598 U.S. 594 (2023), it reiterated that a patent must enable the full scope of its claims without undue experimentation. It also cited Idenix Pharmaceuticals LLC v. Gilead Sciences Inc., 941 F.3d 1149 (Fed. Cir. 2019), explaining that the specification—not the knowledge of skilled artisans—must provide the critical guidance necessary to practice the claimed invention.

The trial evidence further supported the district court's conclusion. AstraZeneca presented unrebutted testimony showing that the dosage ranges disclosed for at least two of the three preferred compounds exceeded the maximum tolerated dose in humans and therefore could not be safely administered daily as required by the claims. Wyeth's own experts agreed that therapeutically effective unit dosages must avoid toxic doses and acknowledged that some disclosed dosage levels were substantially higher than those that could be administered to patients.

According to the Federal Circuit, those facts demonstrated that the patents left skilled artisans to determine through further testing which compounds and dosages were actually operable. The patents, therefore, supplied only a starting point for future research rather than an enabling disclosure of the claimed treatment methods.

The court rejected Wyeth's argument that the district court improperly imposed a non-toxicity or FDA-style safety requirement. Instead, it explained that evidence concerning toxicity was relevant because it illustrated the specification's failure to teach which disclosed dosages could actually be administered daily to patients while producing the claimed therapeutic effect.

Distinguishing its earlier decision in United Therapeutics Corp. v. Liquidia Technologies, Inc., 74 F.4th 1360 (Fed. Cir. 2023), the court observed that although treatment-method patents need not establish FDA approval or clinical efficacy, these patents claimed daily therapeutic dosages for patients while providing no actual dosing examples and leaving practitioners to undertake undue experimentation to identify workable regimens.

Accordingly, the Federal Circuit affirmed the district court's grant of JMOL, invalidating the asserted claims of the ’314 and ’162 patents for lack of enablement under 35 U.S.C. § 112.

The Case is No. 24-2325.

Judge: Lourie, A.

Attorneys: Jennifer L. Swize (Jones Day) for Wyeth LLC. Christopher Neil Sipes (Covington & Burling LLP) for AstraZeneca Pharmaceuticals LP.

Companies: Wyeth LLC; AstraZeneca Pharmaceuticals LP

Cases: Patent FedCirNews