Amgen vs Sanofi – A chronology of the patent battle over Repatha and Praluent
For more than ten years, Amgen, Sanofi and Regeneron were embroiled in a global patent battle to force each other's products off the market. Both sides have now agreed to end the dispute. It is a story of many surprising twists and turns, perseverance, but also joy and deep disappointment for the lawyers. JUVE Patent takes a look back at the most important stages of this epic dispute over cholesterol-lowering drugs.
13 March 2026 by Mathieu Klos
JUVE Patent followed the dispute between Amgen on the one side and Sanofi and Regeneron on the other over cholesterol-lowering drugs for many years. At the heart of the case are the two drugs Repatha and Praluent. While Amgen markets Repatha with the active ingredient evolocumab, Sanofi markets Praluent with the active ingredient alirocumab. Both are anti-PCSK9 antibodies.
One of the reasons this case was so interesting was because the launch of the Unified Patent Court in June 2023 added further fuel to the fire. At this point, the battle had already been fought. Amgen had not managed to prevail decisively in Germany. But in the summer of 2023, both sides were among the first plaintiffs at the new court.
Below JUVE Patent recaps the most important stages in this major dispute.
The US proceedings
2014
The global patent dispute begins. Amgen sues Sanofi and Regeneron in the US for patent infringement. Amgen argues that Praluent infringes its Repatha patents.
2015
Market launch of the two competing products. Both Amgen’s Repatha and Sanofi’s Praluent are the first PCSK9 antibodies to receive drug approval. The rivalry between the two products intensifies the patent dispute.
2017
US judgment in favour of Amgen. The US District Court in Delaware grants Amgen’s request for a permanent injunction prohibiting Sanofi and Regeneron from infringing two patents that Amgen holds for Repatha and from selling Praluent in the US.
2018
A turning point in the US proceedings. The District Court in Delaware invalidates central claims of Amgen’s Repatha patents. Later the US Court of Appeals for the Federal Circuit affirms the ruling.
2023
Final decision of the US Supreme Court. The court confirms the invalidity of key claims in Amgen’s Repatha patents.
Amgen’s first attempt in Europe
2018
September – Sanofi and Regeneron apply for a compulsory licence for its rival product Praluent, but in September 2018 the German Federal Patent Court rejects Sanofi and Regeneron’s application. Amgen can therefore continue to enforce the patent in Germany.
2019
July – Success for Amgen in Germany. The Regional Court Düsseldorf finds Sanofi and Regeneron infringe EP 124. The court issues an injunction (case ID: 4c O 39/26), which Amgen executes against a security deposit of almost €20 million. As a result, Sanofi and Regeneron are no longer able to sell and produce Praluent in Germany.
2020
November – Sanofi and Regeneron take the case to the EPO. The EPO Boards of Appeal restrict Amgen’s EP 2 215 124, which had formed the basis for injunctions in various European countries, including Germany. The decision comes as a surprise to Amgen and its European lawyers. A week later, the Higher Regional Court Düsseldorf allows Sanofi to sell Praluent in Germany again. Sanofi and Regeneron claim damages from Amgen for the period during which the parties were subject to an injunction. Many of the damages cases were still active until the settlement last week.
Amgen and Sanofi escalate the dispute to UPC
2023
June – On the first day of the UPC’s launch, Amgen and Sanofi race to file an infringement and revocation action, respectively, at the UPC’s local and central divisions in Munich. The actions concern Amgen’s patent EP 3 666 797.
2024
January and February – Sanofi and Regeneron go on the offensive and sue Amgen for infringement of EP 3 536 712 at the local division Düsseldorf. In February, they file another infringement suit against Amgen over EP 4 252 857.
July – The Munich central division overturns Amgen’s important EP 797. The ruling removes the basis for a parallel infringement action against Sanofi’s drug Praluent at the local division Munich.
2025
April – Resurrection of EP 797. After four days of oral hearings, the EPO Opposition Division finds Amgen’s EP 797 is valid as granted.
May – Düsseldorf local division dismisses Sanofi and Regeneron’s infringement claim against Amgen’s cholesterol-lowering drug Repatha and Amgen’s counterclaim for revocation against EP 712. Neither side benefit significantly from the ruling. The battle still shows no sign of ending.
November – Amgen’s most important cholesterol-lowering patent EP 797 is valid after all, according to a landmark ruling by the UPC Court of Appeal. The decision allows Amgen to proceed with its infringement action against Sanofi’s drug Praluent at the local division Munich. The hearing is scheduled for November 2026.
2026
March – In a surprising turn of events, Amgen, Sanofi and Regeneron agree to end their years-long patent dispute and withdraw their lawsuits against each other.
