Amgen-Sanofi patent case divides makers of antibody drugs

March 27 (Reuters) - Amgen Inc's battle with Sanofi and Regeneron at the U.S. Supreme Court over its cholesterol drug Repatha on Monday has some drugmakers hoping a ruling will reshape U.S. patent law and competition among companies that make antibody medicines.

In the dispute with Sanofi and partner Regeneron, whose cholesterol-lowering monoclonal antibody drug Praluent works in a similar way as Repatha, Amgen wants the court to rule on how much information it and others need to disclose when describing inventions in patents.

The court has been asked to weigh in on the validity of two patents for Repatha, which garnered sales of $1.5 billion in 2022 for Amgen, to determine whether Praluent infringes them.

The Supreme Court could maintain the legal status quo with its decision – expected by the end of June – which would keep the antibodies market open to numerous players. It could also decide to make it easier for drug companies to muscle competitors out of some market areas with broad patents that cover more ground.

Market research consultant Global Market Insights said the monoclonal antibodies market, which includes big-selling treatments for cancer, high cholesterol, COVID-19 and many other conditions, was worth $181 billion in 2021.

Under U.S. patent law, drug companies can get 20 years of market exclusivity for publishing their inventions, but must describe them clearly enough so skilled people can copy and use them without too much trial and error. Companies that describe inventions too broadly run the risk of having their patents canceled.

Amgen, supported at the Supreme Court by AbbVie, Bristol Myers Squibb and GSK, wants the high court to rule that it can use “genus claims,” which describe a set of characteristics or features common to a group, to describe what Repatha does in broad language.

If successful, Amgen would claim ownership of all antibodies that inhibit the PCSK9 protein, the mechanism of action for both Repatha and Praluent. Other companies could then do the same with their own antibody treatments in other disease areas.

Sanofi and Regeneron, backed by Johnson & Johnson, Pfizer, Eli Lilly < LLY.N> and at least six other companies, have argued that broad patent protection like Amgen is seeking is not allowed by U.S. patent law.

Patent lawyer Irena Royzman of Kramer Levin said the companies taking Sanofi and Regeneron’s side are doing so because a win would allow them to keep bringing competitive drugs to market more easily.

“The J&Js, Eli Lillys and Pfizers recognize that if a particular company controls an entire therapeutic target, we’re all the poorer for it,” Royzman said.

The case might also affect newer technologies used in medicine, such as CRISPR gene editing and messenger RNA, she said.

Amgen's side says if forced to only claim the structural components of their drugs in patents, competitors could easily design around them, disincentivizing investment in monoclonal antibodies.

Baird analyst Brian Skorney said the immediate financial impact of the decision is limited to the companies involved, although it could give some an advantage in future litigation.

Regeneron made $130 million from Praluent in the U.S. last year, and Sanofi collected $400 million in the rest of the world.

U.S. courts have so far sided with Sanofi. A Washington, D.C.-based federal appeals court that covers U.S. patent cases invalidated Amgen's patent claiming ownership of all PCSK9 inhibitors as a whole in 2021.

Amgen sued Sanofi and Regeneron in 2014. Both drugs use lab-made antibodies to block PCSK9 proteins that inhibit removal of bad LDL cholesterol from the blood, but they achieve that result through different chemical combinations.