By John Kruzel and Andrew Chung
WASHINGTON (Reuters) -Amgen Inc sought to convince the U.S. Supreme Court on Monday to revive patents on its cholesterol-lowering drug Repatha, while rival Sanofi SA urged the justices not to stifle competition for therapies to address a common health risk.
The justices heard arguments in Amgen's appeal of a lower court's ruling that invalidated two of its patents on Repatha, a drug that can reduce risk of heart attack and stroke in people with heart disease, after a legal fight with French drugmaker Sanofi and its partner Regeneron Pharmaceuticals Inc.
Questions asked by the justices indicated they were seeking to clarify the technical issues involved, pressing lawyers for both companies about what legal test to use to determine the validity of patents involving laboratory-made antibodies - protective immune system proteins.
The case carries considerable financial stakes. Thousand Oaks, California-based Amgen sold nearly $1.3 billion worth of Repatha worldwide in 2022. Meanwhile, Sanofi and Regeneron last year sold $530 million worth worldwide of their rival drug Praluent, which works by a similar mechanism as Repatha.
Amgen has sought to patent a group of antibodies that help reduce so-called "bad" cholesterol, though its patents disclosed only a subset of antibodies it claimed. At issue is whether a valid patent can cover all the members of an identified group, or if it is limited to only those members of the group specified by the patent owner.
Amgen's lawyer, Jeffrey Lamken, and Sanofi's attorney, Paul Clement, both said a ruling against the company they represent would hurt innovation. Lamken argued that companies would not invest in research if they cannot receive patents for what they invent.
Clement urged the court not to squeeze out competition from the market for cholesterol-lowering drugs.
"We're better off with two competing independently developed therapies," Clement said.
Clement said allowing Amgen's broad patents would freeze out other companies.
The justices focused their questions on trying to determine how many antibodies Amgen's patents actually covered, whether dozens, hundreds or even millions. Amgen has argued that a patent need only to "enable skilled artisans to 'make and use' the invention," not account for the full range of possible forms the invention might take.
Amgen faced tough questions about why its patents described 26 specific examples of antibodies when the scope of its patents would cover a larger number.
"Several times you referred to invention of the antibodies, and I think I'm somewhat confused as to exactly what your invention is. You said it's not just the 26 but it definitely is not millions. So what is it exactly?" conservative Justice Clarence Thomas asked Lamken. "We're not talking about what has been invented with any particular precision."
Liberal Justice Ketanji Brown Jackson wondered how the company has "satisfied enablement" by claiming a patent covering a large group of antibodies but focusing its patents on a smaller group.
If the number claimed in a patent could reach the millions, Jackson asked Amgen's lawyer, "You think that gives others enough notice as to what you've claimed?"
Amgen sued Sanofi and Regeneron in 2014 for patent infringement over Praluent. Both drugs use laboratory-made antibodies to block a protein called PCSK9 that inhibits the removal of bad cholesterol from the blood, but they achieve this result through different chemical combinations.
Bad cholesterol, known LDL, can cause a buildup of plaque in blood vessels and increase the risk of heart disease and stroke.
The Washington-based U.S. Court of Appeals for the Federal Circuit, which hears all patent appeals nationwide, invalidated Amgen's patents that covered PCSK9-blocking drugs as a group.
President Joe Biden's administration, arguing in support of Sanofi, told the justices that Amgen had not disclosed the information needed to make to make its patents valid.
A ruling in the case is expected by the end of June.
(Reporting by John Kruzel and Andrew Chung, with additional reporting by Blake Brittain; Editing by Will Dunham)