Bloomberg Law
March 27, 2023, 4:07 PM

Justices Debate Antibodies in Amgen-Sanofi Drug Patent Fight (1)

Kelcee Griffis
Kelcee Griffis

The Supreme Court appeared to struggle Monday over Amgen Inc.'s arguments in a dispute with Sanofi S.A. that two canceled patents covering its Repatha cholesterol drug contained enough information to merit protection.

Justice Clarence Thomas pressed Amgen counsel Jeffrey Lamken on why he said the patents—related to antibodies called PCSK9 inhibitors, which help reduce LDL cholesterol levels—can be likened to a steam engine design.

According to Lamken, both the engine and Amgen’s cholesterol drug may be made many different ways, but those variations on the original should not invalidate the patent for the base design simply because additional combinations would take a long time to discover.

“We’re not talking about what has been invented with any particular precision,” Thomas said in response. “It seems as though you’re actually trying to patent the use of steam pressure, which can be used for almost anything, and that makes it very difficult because then you’re looking at what can it be used for.”

The case over competing cholesterol drugs offers the justices the chance to define the scope of a statutory requirement known as “enablement.” Put simply, patents must contain enough information to enable someone with expertise in the field to make and use the invention, or to reach “the full scope” of the claims “without undue experimentation.”

In support of Amgen, GSK PLC and AbbVie Inc. told the court that broader patent claims encourage the development of widely applicable treatments and insure a reasonable return on investment. To the contrary, a host of drugmakers, including Pfizer Inc., Eli Lilly and Company, and Genentech Inc., said Sanofi’s argued-for approach promotes the disclosure of specific inventions and breakthroughs over time without unfairly monopolizing far-ranging research areas.

Repatha has 70 percent of the US market for PCSK9-inhibiting drugs, leaving its main rival, Sanofi and Regeneron Pharmaceuticals Inc.’s Praluent, with only $130 million in US sales last year, according to Bloomberg Intelligence analyst Marc Engelsgjerd. The treatments may face rising competition from Novartis’ Leqvio, which was approved by the Food and Drug Administration in late 2021, Engelsgjerd said.

Far-Ranging Pharma Impacts

An eventual decision on whether drug patents have to specify all potential antibodies that could have the same effect—or only spell out some of them to protect an entire category—will impact patent strategies and drug research and development.

In the underlying dispute, Amgen challenged the cancellation of two patents covering its Repatha cholesterol drug that it asserted against Sanofi and Regeneron’s Praluent treatment.

Amgen says it should be able to lay claim to a whole area of potentially unexplored research in a single patent, while Sanofi, Regenron, and the government argue that such patents do not contain enough information to be protected. The US Department of Justice previously suggested the high court reject the case.

Lamken told the justices that the Federal Circuit has displayed a “basic hostility to the breadth” of claims that the Repatha patents contained. Under the Federal Circuit standard Sanofi says should be upheld, Lamken argued that patents developed through intensive research efforts can be overturned too easily and billions of dollars in pharmaceutical investment can evaporate.

“The industry can’t take it any longer,” he said.

Invention’s ‘Full Scope’

Justice Ketanji Brown Jackson appeared particularly interested in ascertaining how many possible antibodies could fall within Amgen’s patent claims. The patents identified 384 antibodies that bind to PCSK9’s “sweet spot” and block its LDL receptors, as well as specific amino acid sequences for 26 of those antibodies.

Aside from these examples, Amgen claimed that any sequence that has the effect of blocking LDL receptors within this category should also be protected using what’s known as functional genus claims.

“So you say you claim a class of antibodies that bind to a particular spot and therefore block. That’s my shorthand. So is that class comprised by 384 species or more?” Jackson asked.

Thomas pressed the point as well: “So in other words, you can’t say how many?”

Sanofi counsel Paul D. Clement said this debate means the full scope of the claims is not enabled, meaning that it doesn’t give a scientist a roadmap to reproduce every claimed antibody.

The court should uphold the status quo and insist that inventors clearly spell out what they’re claiming, he said, leaving room for other innovators to explore the same field.

“We’re better off with two independently developed therapies,” Clement said.

‘Tweaks at the Margins’

Sanofi wasn’t immune to the justices’ skepticism. Jackson questioned whether upholding the Federal Circuit’s patent-scope standard would preclude any patent that involves a limited amount of experimentation from gaining protection.

“I’m a little worried that your view would mean we can’t have patents where some experimentation is required,” she said.

Clement said “tweaks at the margins” of a patent should be allowed through experimentation. However, he argued that Amgen called for a cumbersome set of tests to ensure that any new cholesterol treatment doesn’t infringe its patents, and he said that extent of experimentation should not be allowed.

Arguing for the government in support of Sanofi, Colleen Sinzdak approached the concept from a different angle.

She raised the doctrine of equivalents, which holds that a party can be found liable for patent infringement even if their new invention differs slightly from a pre-existing invention.

The doctrine requires that a pre-existing concept be distinct if it’s to be afforded protection—or, as Sinzdak said, an inventor must build a different mousetrap, not a better one.

Amgen established that it and Sanofi’s medicines were not equivalents, Sinzdak said, so that means Amgen’s patents were obligated to spell out all of the combinations they planned to protect.

“Because they’re not equivalent, you have to enable all the different antibodies,” she said.

MoloLamken LLP represents Amgen. Clement & Murphy PLLC represents Sanofi. The US Solicitor General’s office argued in support of Sanofi.

The case is Amgen Inc., et al., Petitioners vs. Sanofi, et al., U.S., No. 21-757, argued 3/27/23.

To contact the reporter on this story: Kelcee Griffis in Washington at

To contact the editor responsible for this story: Jay-Anne B. Casuga at

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