Today the Federal Circuit reversed a district court’s JMOL and held that claims to a method of treating headaches using a genus of antagonistic anti-CGRP antibodies satisfied both the written description and enablement requirements. In particular, the court held that the prior art evidence demonstrates the genus was well known, methods of making the antibodies were routine and “critically” all of the antibodies in the genus worked in the method of treatment—even the disclosure of a single embodiment for use in the method of treatment satisfied the written description and enablement requirements.  

In the district court, Teva asserted several patents, including patents to anti-CGRP antibodies and methods of treatment. Teva asserted a number of its patents against Lilly in district court. In response, Lilly challenged all of the patents in IPRs, arguing that anti-CGRP antibodies were well known—the prior art was “replete with exemplary disclosures.” The board agreed with Lilly on the antibody patents and found them unpatentable, but upheld the method of treatment claims.   

The district court litigation then proceeded on Teva’s method claims, which a jury ultimately found those claims willfully infringed, sufficiently described and enabled. On JMOL, the district court acknowledged the jury could have found that anti-CGRP antagonist antibodies were well known and disclosed, that methods of humanizing such antibodies were well known and that all such antibodies would treat headaches. The district court nonetheless concluded the claims covering a method of treating headaches with a genus of anti-CGRP antibodies were invalid for both lack of written description and enablement.

The Federal Circuit reversed on appeal. Addressing written description, the court stressed that the claimed invention was not a genus of anti-CGRP antibodies, but rather the use of those antibodies to treat headaches. On the contrary, based on Lilly’s own statements, the anti-CRGP antibodies were “well known, replete, or extensively described in the prior art.” The court noted that although the specification only disclosed one humanized anti-CGRP antagonist antibody, it also disclosed several murine antibodies and well-known methods of humanizing those antibodies. And “critically,” the record included evidence demonstrating that a skilled artisan would have understood from the specification that all humanized anti-CGRP antagonistic antibodies treat headaches. Based on all of this evidence, the Federal Circuit held that the jury could have reasonably found adequate written description support for the claims. In so doing, the court distinguished claims to broad methods of performing a function, like a method of antagonizing X protein by administering a compound that antagonizes X protein, from the claims here that focused on treating a specific indication, explaining that treating a headache is different from a method of performing the function that characterizes the antibody. 

Turning to enablement, the Federal Circuit distinguished this case from prior cases like Amgen, stating that Lilly’s reliance on those cases would have been more persuasive if the claims were directed to the genus of anti-CGRP antibodies themselves. But the claims here claimed only the use of those antibodies for the “limited purpose of treating headaches.” “In light of the well-known status of anti-CGRP antagonist antibodies and the routine nature of humanization,” the appropriate question for enablement is whether a POSA could have determined which antibodies treat headaches without undue experimentation. And that question was answered directly by the specification, which disclosed that all antagonistic anti-CGRP antibodies work for that purpose. 

Teva Pharms Int’l GMBH v. Eli Lilly & Co., No. 24-1094 (Fed. Cir. Apr. 16, 2026)