Federal Circuit Denies Rehearing En Banc in Teva v. Lilly; Judge Dyk Dissents.

What the court did

On September 30, 2026, the Federal Circuit issued a per curiam order in Teva Pharmaceuticals International GmbH v. Eli Lilly and Company, No. 2024-1094, denying panel rehearing and rehearing en banc on Lilly's petition. After referral to the panel and then to the active circuit judges, "[t]he court conducted a poll on request, and the poll failed." The order gives no vote count or reasons.

The order lists Chief Judge Moore and Circuit Judges Lourie, Dyk, Prost, Reyna, Taranto, Chen, Hughes, Stoll, Cunningham, and Stark; Circuit Judge Newman did not participate. District Judge Richard G. Andrews, who sat on the panel by designation, participated only in the panel rehearing decision. Judge Dyk dissented alone; no judge wrote a concurrence. The court granted leave to file amicus briefs to Ipsen Biopharmaceuticals, Merck Sharp & Dohme, Amgen, Sanofi, Johnson & Johnson, Nagra USA, and three individuals.

The panel decision

Judge Prost wrote the April 16, 2026 panel opinion (172 F.4th 1367), joined by Judges Cunningham and Andrews. Teva's 2018 suit alleged that Lilly indirectly infringed three Teva patents through its Emgality product. A jury found willful infringement and rejected Lilly's written-description and enablement defenses. The District of Massachusetts (No. 1:18-cv-12029) then granted Lilly judgment as a matter of law (JMOL) of invalidity on both grounds. The panel reversed and remanded.

The asserted claims are claim 30 of U.S. Patent No. 8,586,045 and claims 5 and 6 of each of U.S. Patent Nos. 9,884,907 and 9,884,908. The panel treated claim 30 as representative, quoting it with claim 17: "A method for reducing incidence of or treating headache in a human, comprising administering to the human an effective amount of an anti-CGRP antagonist antibody, wherein said anti-CGRP antagonist antibody is a . . . humanized monoclonal antibody." The specification disclosed one humanized antibody, G1, the active ingredient in Teva's Ajovy product.

The panel's reasoning

On written description, the panel applied precedent on "a well-known genus that is not, itself, the invention." It held that a reasonable jury could have found the antibodies and methods of making them well known and humanization routine (as Lilly itself had said in inter partes reviews), and that a skilled artisan would have understood from the specification that all humanized anti-CGRP antagonist antibodies treat headache.

On enablement, the panel assumed, "solely for argument's sake," that making and humanizing all such antibodies would have required undue experimentation, and said that if the claims were to the antibody genus itself, "this case would resemble Amgen." But it held that the claims "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." Because the specification disclosed that all such antibodies treat headache, the panel wrote that, in the context of these claims, finding or making all of them would be "more akin to extra credit than a necessary research assignment left to others to complete."

Judge Dyk's dissent

Judge Dyk wrote that the panel's holding "creates confusion as to the enablement standards for method claims, will undermine medical innovation by sustaining overly broad claims, and is contrary to Supreme Court enablement precedent." He read claim 30 as reciting two functional limitations, an antagonist antibody and headache treatment, with the second adding "nothing of substance" to the first. He cited record evidence that identifying and humanizing such antibodies took months of benchtop and animal testing at "tens of thousands of dollars per antibody."

He wrote that where the record suggests no use for the antibodies other than treating headache, "the practical scope of the method claim is equal to the scope of the compound," and, quoting Amgen Inc. v. Sanofi, 598 U.S. 594 (2023), that a patent "must enable the full scope of the invention as defined by its claims." Treating the method claim as narrower, he wrote, "simply makes no sense." He added: "Claiming a method of use that depends on a recited component cannot excuse the enablement requirement of the component."

Under the panel's reasoning, he wrote, the Amgen patentee "could have evaded the enablement requirement" by claiming a cholesterol-lowering method. Quoting the Johnson & Johnson and Nagra USA brief, he wrote that the opinion creates an "end-run around Amgen," and noted that amici "representing the pharmaceutical industry, not known for urging onerous requirements for patentability, view the panel decision as confusing and erroneous."

Why it matters

The denial leaves in place the panel's precedential holding that, given these method claims and the jury's supportable findings, JMOL of invalidity was improper. The panel did not decide whether a claim to the antibody genus itself would be enabled.

What to watch next

Under Federal Rule of Appellate Procedure 41, the mandate issues seven days after entry of an order denying a timely rehearing petition unless the court shortens or extends that time, and a party may move to stay it pending a certiorari petition.

Lilly may petition for a writ of certiorari. Under Supreme Court Rule 13, the 90-day period runs from the September 30 denial of rehearing, and a Justice may extend it by up to 60 days for good cause.

After the mandate issues, the case returns to the district court on remand; the parties can also settle or dismiss it at any time.