SCOTUS hands win to Sanofi, Regeneron in long-running PCSK9 feud with Amgen

After numerous twists and turns, a highly divisive patent infringement case between Amgen and partners Sanofi and Regeneron has come to an end at the U.S. Supreme Court.

The nine justices voted unanimously to uphold (PDF) a lower court ruling invalidating a pair of patents on Amgen’s PCSK9 cholesterol med Repatha.

The case stretches back to 2014, when Amgen first sued Sanofi and Regeneron for allegedly treading on Amgen intellectual property with their rival PCSK9 drug Praluent, under development at the time as alirocumab.

Praluent and Amgen's Repatha won U.S. approvals just weeks apart in 2015. Both drugs work to help lower “bad” LDL cholesterol by blocking the protein PCSK9.

In 2019, a judge ruled that certain claims of two Amgen patents covering Repatha were invalid. Amgen took that loss to federal appeals court, where it was rejected. The company ultimately petitioned the U.S. Supreme Court to hear the case in November.  

“This ruling reinforces our longstanding belief that Amgen's asserted patent claims are invalid and represents an unequivocal win for America's innovation economy, its scientists, and researchers,” Sanofi said in a release.

Much of the long-running patent feud comes down to the legal requirement on “enablement,” which dictates that a patent must contain enough detail to allow a person of ordinary skill in the relevant trade to make or use an invention without “undue” trial and error. The law is meant to ensure inventions truly advance their fields. Since no patent lasts forever, inventions must be clearly described so that others can make and use them once they lose exclusivity. 

In the latest decision, the Supreme Court ruled that Amgen failed to provide enough detail to recreate the full scope of its claimed invention.

Worldwide, Amgen’s Repatha logged around $1.3 billion in full-year 2022 sales. Comparatively, Sanofi recorded $376 million in 2022 sales of Praluent, which it shares with Regeneron.

Sanofi’s win could have big implications for the rest of the industry.

Previously, Amgen argued that the court ought to back broader protections on antibody drugs like Repatha, suggesting that without those intellectual property bulwarks, me-too drugs can emerge with minor changes to successful meds without committing the same resources to research. 

Sanofi and Regeneron countered that letting Amgen’s Repatha patents stand could allow companies to deflect entire classes of rival drugs by claiming overly broad protections.

Ultimately, the Supreme Court agreed with Sanofi and Regeneron.

“Amgen seeks to monopolize an entire class of things defined by their function—every antibody that both binds to particular areas of the sweet spot of PCSK9 and blocks PCSK9 from binding to LDL receptors,” the Justices wrote in their unanimous opinion. “The record reflects that this class of antibodies does not include just the 26 that Amgen has described by their amino acid sequences, but a 'vast' number of additional antibodies that it has not.”