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Explore the latest in patent, trademark, and copyright cases on the Merchant & Gould LLP blog. Stay informed with expert insights on intellectual property law updates.

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Last week, the U.S. Court of Appeals for the Federal Circuit issued a precedential decision in <a href="https://www.cafc.uscourts.gov/opinions-orders/24-1094.OPINION.4-16-2026_2677411.pdf">Teva Pharmaceuticals International GmbH v. Eli Lilly and Company, No. 2024-1094 (Fed. Cir. Apr. 16, 2026)</a>, reversing the district court’s grant of judgment as a matter of law (“JMOL”) that the asserted claims of Teva’s “headache patents” are invalid for failure to satisfy the written description and enablement requirements of 35 U.S.C. § 112.&nbsp;

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Teva Pharmaceuticals International GmbH (“Teva”) sued Eli Lilly (“Lilly”) for indirect infringement of three patents covering methods of treating headaches using humanized anti-CGRP antagonist antibodies. A jury found willful infringement and rejected Lilly’s invalidity defenses. Although the district court acknowledged that the jury could have found that murine antibodies were known in the art and that humanization techniques were routine, it nonetheless granted Lilly’s motion for JMOL, holding the claims invalid for lack of written description and enablement.

The Federal Circuit reversed. The Court held that a reasonable jury could find adequate written description despite the specification disclosing only one humanized antibody species. Central to its reasoning were the following: anti-CGRP antagonist antibodies and methods of making them were well known in the art; humanization techniques were routine by the priority date; and the invention was not the antibodies themselves, but their use to treat headaches. Relying on Ajinomoto, Herschler,and Fuetterer, the Court distinguished between claims to a novel genus and claims that use a known genus as part of a different invention. The Court concluded that the jury could reasonably have found that the specification disclosed a “representative number of species” for the claimed method. The Court rejected Lilly’s argument that the lack of multiple humanized antibody examples was fatal and clarified that representativeness does not require disclosure of a composition structurally similar to the accused product.

The Court further held that the enablement ruling rose and fell with written description. The Court distinguished Amgen v. Sanofi, where the claims at issue covered an entire antibody genus, from the narrower claims here, which are directed only to a specific use—treating headaches. Because the jury could reasonably have found that all humanized anti-CGRP antagonist antibodies would treat headaches, the Court held that the patents did not impose an undue experimentation burden and that any additional antibody development was “extra credit,” not a required research assignment.

CAFC Reverses Grant of JMOL of Invalidity

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