Federal Circuit Reverses Teva Headache Patent Invalidity, Distinguishing Amgen on §112 Written Description and Enablement

The U.S. Court of Appeals for the Federal Circuit issued a precedential opinion on April 16, 2026, reversing a judgment as a matter of law (JMOL) of invalidity entered by the U.S. District Court for the District of Massachusetts in Teva Pharmaceuticals International GmbH v. Eli Lilly and Company (No. 24-1094). The case involved three Teva patents — U.S. Patent Nos. 8,586,045, 9,884,907, and 9,884,908 — covering methods of using humanized anti-CGRP antagonist antibodies to treat headache.

The district court had granted Lilly’s JMOL motion, holding that all asserted claims failed both the written description and enablement requirements of 35 U.S.C. §112. The lower court applied the exacting genus-claim standard articulated by the Supreme Court in Amgen Inc. v. Sanofi, 598 U.S. 594 (2023). On appeal, the Federal Circuit reversed, finding the JMOL improper on both statutory grounds.

The Federal Circuit drew a sharp distinction between Teva’s claims and those at issue in Amgen. In Amgen, the challenged claims broadly encompassed entire genera of antibodies defined solely by their functional binding properties, requiring would-be practitioners to engage in substantial research to identify and make species within the claimed genus. By contrast, the Teva patents “do not claim humanized anti-CGRP antagonist antibodies themselves; instead, they claim only the use of such antibodies for the different, limited purpose of treating headache.” The invention, in other words, was the therapeutic indication — not the antibody genus.

That characterization governed the §112 analysis. The court found that anti-CGRP antagonist antibodies and methods of humanizing murine antibodies were well-known and extensively documented in the prior art at the time of the claimed invention. Citing Ajinomoto Co. v. ITC, In re Herschler, and In re Fuetterer, the Federal Circuit held that where a well-known genus already exists and routine modification techniques are established in the art, method-of-use claims directed to that genus need not satisfy the same demanding disclosure threshold as genus claims to the biological entities themselves. Adapting language used in prior opinions, the court observed that locating or producing all antibodies within the known genus would amount to “more akin to extra credit than a necessary research assignment left to others to complete.”

This decision should be read alongside — and distinguished from — the Federal Circuit’s earlier ruling in the Teva–Lilly litigation reinstating a $177 million damages verdict, which addressed infringement and claim scope rather than patent validity under §112.

The practical significance for pharmaceutical and biotech patent prosecution is substantial. Post-Amgen, practitioners have faced uncertainty about whether antibody-related claims of any kind can withstand §112 scrutiny. Today’s decision confirms that method-of-use claims targeting a known antibody class for a specific therapeutic indication remain a viable — and defensible — claiming strategy, provided the specification adequately establishes that the genus and its humanization are well understood in the art. The ruling creates a meaningful pathway for companies to protect therapeutic use innovations without needing to satisfy the exhaustive disclosure demands applicable to functional genus claims.

The full Federal Circuit opinion in No. 24-1094 is available on the court’s website. Analysis is also available via IPWatchdog.