VIRGINIA — Pharmaceutical company Sandoz has filed a federal lawsuit accusing Amgen of orchestrating an illegal scheme to block biosimilar competition for its blockbuster arthritis drug Enbrel, resulting in inflated prices for American patients and insurers.

The Enbrel biosimilar lawsuit, lodged Friday in the Eastern District of Virginia, claims that Amgen violated antitrust laws by engaging in anti-competitive behavior, including acquiring strategic patents and manipulating licensing agreements to shut out rivals from the etanercept market—Enbrel’s active ingredient.

Decades-Long Monopoly Alleged

Sandoz asserts that Amgen’s anti-competitive conduct dates back to 2002, following its acquisition of Enbrel’s original manufacturer, Immunex. By 2004, Enbrel sales had ballooned to nearly $2 billion annually, making it Amgen’s highest-grossing drug.

Fearing future competition from biosimilars after its patents were set to expire in 2015, Amgen allegedly moved to secure exclusive control over key patent rights from F. Hoffmann-La Roche, the Swiss firm that first sequenced Enbrel’s core receptor technology. Although Roche had licensed these patents non-exclusively, Amgen allegedly transformed that deal into an exclusive arrangement, effectively locking out competitors like Sandoz.

“Amgen chose to scheme,” Sandoz claimed in the suit. “Rather than compete fairly, it pursued a course to extend its monopoly beyond what the law allows.”

The Patent Buy That Changed the Game

In 2004, Amgen purchased Roche’s patent rights, which Sandoz claims served no purpose other than to extend its legal power to block biosimilars. When Sandoz attempted to enter the U.S. market with its Enbrel alternative, Erelzi, Amgen used those patents to halt the launch—actions Sandoz now argues violate Section 2 of the Sherman Act.

While Sandoz’s biosimilar has been approved and successfully marketed in Europe since 2017—cutting Enbrel’s prices by nearly 50% in some markets—the U.S. market has remained closed, costing the healthcare system billions, according to the suit.

A Costly Delay for American Patients

The complaint highlights Sandoz’s role in reducing drug costs through biosimilars, pointing to its earlier launch of Zarxio—a biosimilar to Amgen’s Neupogen—which saved U.S. consumers about $1.6 billion from 2016 to 2022.

But due to Amgen’s “unlawful and anticompetitive scheme,” Sandoz says it has been unable to offer the same cost-saving competition for Enbrel in the U.S.

“Unless stopped, Amgen will continue to rake in billions by keeping affordable biosimilars off the market until at least 2029,” the complaint states. In 2024 alone, Enbrel generated $3.288 billion in revenue for Amgen, with prices rising nearly every year.

Legal Representation and Case Details

Sandoz is represented by attorneys from Alston & Bird LLP, including Scott J. Pivnick, Ross R. Barton, Matthew D. Kent, Troy A. Steam, and Karla Doe.

Amgen has not yet issued a public comment on the lawsuit. Legal counsel for Amgen was not listed in court filings available as of Monday.

The case is Sandoz Inc. v. Amgen Inc. et al, case number 2:25-cv-00218, filed in the U.S. District Court for the Eastern District of Virginia.