Source: IPWatchdog

The U.S. Court of Appeals for the Federal Circuit (CAFC), in a precedential decision, affirmed a district court ruling that certain claims of Wyeth LLC’s two patents for methods of cancer treatment are invalid for lack of enablement. Wyeth had sued AstraZeneca Pharmaceuticals in September 2021, alleging induced infringement of U.S. Patents 10,603,314 and 10,596,162 based on marketing, distribution, and sales of the irreversible EGFR inhibitor Tagrisso (osimertinib). The district court had construed the claims to require administering daily a “unit dosage” of an irreversible EGFR inhibitor that covalently binds a specific part of the enzyme and adopted a definition of “unit dosage” as a physically discrete unit containing a predetermined quantity calculated to produce the desired therapeutic effect with required diluents.

A jury initially found induced infringement, no invalidity, and awarded Wyeth $107,500,000, but AstraZeneca renewed a motion for judgment as a matter of law (JMOL) that the claims were invalid for lack of enablement; the district court granted JMOL. The district court concluded that identifying a non‑toxic, therapeutically effective unit dosage for daily administration was highly unpredictable and would require undue experimentation, noting unrebutted evidence that some disclosed dosage levels would be toxic and that the asserted patents provided only a starting point requiring iterative trial‑and‑error by a skilled artisan. On appeal Wyeth argued the district court improperly altered its claim construction post‑verdict and that the JMOL was unsupported by the evidence, but the CAFC rejected those arguments. The CAFC held that AstraZeneca proved by clear and convincing evidence that the asserted claims require undue experimentation to determine a non‑toxic daily unit dosage. The patents’ specification lacked working examples of calculated unit dosages and relied on in vitro data without teaching how to extrapolate to in vivo dosing or otherwise instruct a skilled artisan how to calculate the claimed unit dosage. Although the specification recited dosage ranges, they were described as “general” and “projected” with no explanation of how they were derived or how to select among them for a given compound. The court also noted that Wyeth’s citations to certain studies and clinical experience did not address whether the specification itself teaches how to determine the claimed therapeutically effective daily unit dosage. Evidence, including testimony Wyeth’s experts did not rebut, indicated that therapeutically effective levels for the disclosed compounds could exceed the maximum tolerated dose in humans, reinforcing the lack of guidance. Recognizing that claiming dose ranges without clinical data can be common, the CAFC concluded these patents nonetheless left too much to the practitioner—some disclosed doses were toxic and no actual dosages for any claimed compound were provided—so the district court’s JMOL of invalidity was affirmed.