Federal judge blocks Colorado's unprecedented price cap on Amgen's Enbrel

A US federal court has halted Colorado's attempt to impose a US$31,200 annual price cap on Amgen's arthritis drug Enbrel, ruling that the pharmaceutical company would likely suffer irreparable harm. The decision represents a significant blow to state-level efforts to control prescription drug costs and raises questions about the legal boundaries of pharmaceutical price regulation.

A federal judge has halted Colorado's groundbreaking attempt to impose a price cap on Amgen's blockbuster arthritis medication Enbrel, marking a significant setback for the state's efforts to control pharmaceutical costs. Chief Judge Daniel Domenico of the Denver federal court granted a preliminary injunction on Wednesday, ruling that the pharmaceutical giant would likely suffer substantial and irreparable harm from being forced to charge lower prices for the drug.

The judge noted that such a cap could have far-reaching consequences for Amgen's future contract negotiations with wholesalers and distributors. In his ruling, Judge Domenico stated that "as a matter of basic economic logic, Amgen is likely to be significantly harmed by a cap on the price of its product, even if the cap applies unevenly" throughout the supply chain. Whilst acknowledging Colorado's legitimate interest in helping patients afford essential medications, he emphasised that the state could pursue alternative approaches such as subsidies or price negotiations similar to those employed by the federal government. However, he concluded that "capping the price of a patented drug" exceeded the state's authority.

The Colorado Prescription Drug Affordability Board had voted in October to cap Enbrel prices at $600 for a 50-milligram weekly dose, equivalent to $31,200 annually, with the measure scheduled to take effect on 1st January 2027. This represented a dramatic reduction from Enbrel's current list price, which exceeds $100,000 per year. The decision made Colorado the first state in the nation to impose a price cap on a specific prescription drug, following years of establishing the board, gathering data and conducting analysis.

Amgen, based in Thousand Oaks, California, had challenged the cap through legal action, arguing that it conflicted with federal patent law, violated the company's due process rights under the United States Constitution, and threatened patients' access to necessary treatment. The company's position centres on the argument that federal patent law exists to promote pharmaceutical research and development by granting companies an exclusive window to sell their products at market prices. Amgen contends that Colorado's board specifically targeted drugs still under patent protection, as evidenced by their focus on Enbrel whilst avoiding similar drugs like Humira, which is now off-patent and has generic alternatives available.

Enbrel, whose chemical name is etanercept, is used to treat rheumatoid arthritis and plaque psoriasis. The medication remains one of Amgen's most significant products, generating $2.23 billion in sales during 2025. The company had faced a deadline of 5th July to decide whether to continue selling the drug in Colorado, with statutory requirements mandating at least 180 days' notice before withdrawing a medication from the state or facing potential penalties of $500,000.

Genna Morton, a spokeswoman for Colorado's Division of Insurance, stated that the agency could not comment on pending litigation. Amgen and its legal representatives did not immediately respond to requests for comment following the ruling.

The case highlights the ongoing tension between state efforts to control pharmaceutical costs and federal patent protections. The United States pays approximately three times as much as other high-income countries for branded medications, prompting both federal and state governments to pursue various policies aimed at reducing drug prices. Colorado's attempt to establish an upper payment limit represented one of the most aggressive state-level interventions to date, though the judge's ruling suggests significant legal obstacles remain for such approaches.

The preliminary injunction means the price cap will not take effect whilst the lawsuit proceeds, leaving the broader legal questions surrounding state prescription drug affordability boards unresolved for now. The outcome of this case could have significant implications for other states that have established similar boards and are considering implementing their own price controls on pharmaceutical products.

Source: Judge blocks Colorado's first-of-its-kind price cap on Enbrel [Accessed July 2, 2026] https://www.reuters.com./legal/litigation/judge-blocks-colorados-first-of-its-kind-price-cap-amgens-enbrel-2026-07-01/