Bloomberg Law
Dec. 9, 2020, 6:02 PM

Amgen Antibody Patent Faces ‘Uphill Battle,’ Appeals Judge Says

Perry Cooper
Perry Cooper
Legal Reporter

Amgen Inc. met with resistance from a panel of Federal Circuit judges in its bid to revive its patents for the cholesterol drug Repatha, which were invalidated in a long-running dispute with Sanofi and Regeneron Pharmaceuticals Inc.

A federal trial court most recently found Amgen’s two patents should never have been granted because it would take a substantial amount of time and effort to enable an expert to recreate the genus of antibodies claimed by the patents. The enablement requirement is meant to ensure that the invention is described well enough that it can be made and used without too much trial and error.

“That sounds like undue experimentation, and that’s the key factor in enablement,” Judge Alan D. Lourie told Amgen’s counsel Jeffrey Lamken of MoloLamken LLP in Washington. “So you’ve got a pretty uphill battle,” Lourie said.

The case could have implications for drugmakers and biotechnology companies that produce pioneering antibody-based drugs, including those being developed to treat and prevent Covid-19.

How Many Antibodies Covered?

Lamken argued Amgen’s patents clearly explain how a skilled artisan can identify all 400 distinct antibodies it covered using the standard tools of antibody science.

“I don’t think in terms of this road map, there’s any real question on this record that it is fully enabled,” he said.

“I’m having trouble seeing where your road map and your examples get you to enablement of the full scope of the claims,” Chief Judge Sharon Prost said.

Sanofi-Regeneron’s attorney Matthew Wolf challenged the number 400, which he said Amgen never presented to the jury or the trial court. “There’s no real dispute that you would have to test each of the millions of possible candidates for their function,” Wolf of Arnold & Porter Kaye Scholer LLP in Washington said.

The number of possible antibody candidates is “astronomical if you follow the rules of the patent,” Wolf said.

Wolf used the district court’s comparison to the California Gold Rush, saying “the fact that you knew that there was gold in the hills and that you knew how to use a pan to find it doesn’t mean you were entitled to every ounce of gold on every square mile of the California countryside.”

Judge Todd M. Hughes asked why the number of experiments matters if it just requires running conventional tests to determine how well the antibodies work.

“Why is the fact that you might have to do that a million times versus 100 times—as long as qualitatively it’s not difficult—undue experimentation?” Hughes asked.

Amgen’s expert said that analyzing millions of antibodies to see if they work “would be an enormous amount of work and more than any scientist would even contemplate doing,” Wolf said. “I can’t think of a better definition of undue experimentation.”

Lamken defined it differently.

“It’s only when you have failures that impede your ability to make and use the invention that you have undue experimentation,” he said. “Being able to successfully make these products isn’t undue experimentation, it’s production.”

Amgen sued Sanofi and Regeneron, alleging their competing drug Praluent infringed its patents for Repatha. Amgen’s patents are related to a genus of antibodies called PCSK9 inhibitors, which help patients with ultra-high bad, or LDL, cholesterol who have difficulty getting their condition under control with widely used statins such as Pfizer Inc.’s Lipitor.

The case isAmgen Inc. v. Sanofi, Fed. Cir., No. 20-1074, argued 12/9/20.

To contact the reporter on this story: Perry Cooper in Washington at

To contact the editors responsible for this story: Renee Schoof at; Keith Perine at