Repatha Lawsuit: Jury Verdict, Patents, and Global Settlement

The Repatha lawsuit story is really two stories: a patent war between Amgen and Sanofi/Regeneron that reached the U.S. Supreme Court in 2023, and a separate antitrust case in which a Delaware jury found in 2025 that Amgen had used its other blockbuster drugs to shut Regeneron’s competing cholesterol drug out of the market. Both were resolved by a global settlement announced in March 2026.

What Regeneron Accused Amgen of Doing

Regeneron Pharmaceuticals sued Amgen in the U.S. District Court for the District of Delaware in May 2022. The claim: Amgen was using anticompetitive tactics to block Praluent (alirocumab), Regeneron’s PCSK9 inhibitor, from pharmacy formularies where it would compete head-to-head with Repatha (evolocumab).

The alleged mechanism was a cross-therapeutic bundle. Amgen offered pharmacy benefit managers large rebates on two unrelated, high-demand drugs, Enbrel (an anti-inflammatory) and Otezla (a psoriasis treatment), but conditioned those rebates on the PBMs giving Repatha exclusive or preferred status and excluding Praluent. Regeneron argued that because it did not have a comparable portfolio to offer competing rebates, it was locked out no matter how Praluent performed clinically or on price.¹

Regeneron also alleged Amgen enforced the arrangement with “rebate cliffs,” steep economic penalties for PBMs that refused the bundle, and that some bundling terms were kept out of written contracts through verbal agreements.² The PBMs involved included Express Scripts, UnitedHealth’s Optum, and CVS.³

The 2025 Jury Verdict

On May 15, 2025, the jury sided with Regeneron. It found that Amgen had violated the Sherman Act on both monopolization and restraint-of-trade grounds, along with the Clayton Act, New York’s Donnelly Act, California’s Cartwright Act, and Delaware tort law.¹ The jury specifically found that both Repatha and Enbrel possessed market power in their relevant product markets and that Amgen’s conduct “substantially foreclosed” Regeneron from competing.³

The damages award came to roughly $406.8 million: $135.6 million in compensatory damages and $271.2 million in punitive damages.⁴ The court noted the punitive award was intended to punish outrageous conduct and deter similar behavior.¹

Amgen filed a renewed motion for judgment as a matter of law on June 12, 2025, challenging the verdict.³ Oral arguments on post-trial motions covering a permanent injunction, a constructive trust, and prejudgment interest were scheduled for August 2025, and no decision on those motions had been released as of mid-2026.²

The Patent Fight Behind It

The antitrust case was one strand of a much longer dispute. In 2014, Amgen sued Sanofi and Regeneron for patent infringement, claiming Praluent infringed its patents covering anti-PCSK9 antibodies. Amgen initially won a permanent injunction from the Delaware district court in January 2017 that would have barred Praluent from the U.S. market, though enforcement was delayed 30 days to allow an expedited appeal.⁵ That victory did not hold. By 2018, the Delaware court had invalidated central claims of Amgen’s patents, and the Federal Circuit affirmed.⁶

The Supreme Court Ruling

The case reached the U.S. Supreme Court as Amgen Inc. v. Sanofi (No. 21-757). On May 18, 2023, the Court issued a unanimous decision authored by Justice Neil Gorsuch, ruling against Amgen. The Court held that Amgen’s patents failed the Patent Act’s enablement requirement. Although Amgen had identified 26 specific antibodies by their amino acid sequences, it tried to claim an entire class of antibodies that were not adequately described in the specification. When a patent claims an entire class of items, the Court held, the specification must enable a skilled person to make and use the full scope of that class, and Amgen’s did not.⁷

The ruling was widely seen as raising the bar for broad genus claims in biotechnology patents, meaning companies could no longer claim vast categories of biological molecules based on a handful of representative examples.⁷

The 2026 Global Settlement

In March 2026, Amgen, Sanofi, and Regeneron reached a global settlement ending all of their disputes. Sanofi confirmed the resolution on March 16, 2026.⁸ The deal covers the U.S. antitrust claims, the U.S. patent litigation, and the patent oppositions and appeals pending in Europe and other jurisdictions. All three companies agreed to withdraw their pending lawsuits, including damages claims tied to earlier injunctions.⁶ The financial terms have not been publicly disclosed.⁹

FTC Scrutiny of the Same Bundling Playbook

Amgen’s bundling strategy had already drawn federal attention before the jury weighed in. When Amgen pursued its $27.8 billion acquisition of Horizon Therapeutics, the Federal Trade Commission challenged the deal partly out of concern that Amgen would apply the same cross-therapeutic bundling approach to Horizon’s drugs Tepezza and Krystexxa. The FTC explicitly referenced the then-pending Regeneron antitrust case in its complaint.¹⁰

Amgen denied the allegations. It argued it had no incentive or ability to bundle pharmacy-benefit products like Enbrel with medical-benefit products like Tepezza and Krystexxa, said it had committed to the FTC that it would not bundle its products with Horizon’s medicines, and offered to formalize that commitment in a binding consent order.¹⁰

What This Meant for Patients

The formulary exclusions at the center of the antitrust case had consequences for the people trying to fill prescriptions. PCSK9 inhibitors were approved by the FDA in 2015 for high-risk patients with familial hypercholesterolemia and atherosclerotic cardiovascular disease, but coverage was hard to get. A 2016 study found that initial denial rates for PCSK9 inhibitor prescriptions ran around 80%, and clinicians reported their on-label prescriptions were rejected 80% to 90% of the time. Even after appeals, final approval rates were only between 25% and 50%.¹¹

List price, roughly $14,000 per year for either drug, was one factor. PBMs were another: they controlled formulary placement and required extensive prior authorization. The Regeneron verdict suggests that at least some of those formulary decisions were shaped not by cost-effectiveness calculations alone but by Amgen’s bundling leverage.¹¹

These are the lawsuits Repatha has been at the center of. The file does not describe any personal-injury or product-liability litigation over the drug itself; the disputes have been between drugmakers over patents and competition, not between patients and Amgen.

1
Regeneron. Regeneron Prevails Over Amgen in Antitrust PCSK9 Lawsuit
2
American Bar Association. Dissecting the Regeneron Trial
3
Haug Partners. Regeneron Pharmaceuticals, Inc. v. Amgen Inc. – Jury Finds Rebate Offers on Bundled Drugs Violate Antitrust Laws
4
Fierce Pharma. Amgen on Hook to Pay More Than $400M After Regeneron Triumphs in Cholesterol Drug Antitrust Suit
5
Amgen. Court Grants Permanent Injunction for Infringement of Amgen’s Repatha Patents
6
JUVE Patent. Amgen vs Sanofi: A Chronology of the Patent Battle Over Repatha and Praluent
7
Oyez. Amgen Inc. v. Sanofi
8
Law360. Amgen and Sanofi End Repatha IP Fight Heard by Justices
9
Pearce IP. Sanofi Regeneron Amgen Settle Dispute Over PCSK9 Inhibitors Praluent Repatha
10
FTC. Answer and Defenses of Respondents Amgen Inc. and Horizon Therapeutics plc
11
PubMed Central. PCSK9 Inhibitor Access Barriers