Pharmaceutical giant Amgen has filed a second federal lawsuit against Colorado's Prescription Drug Affordability Board, challenging the state's groundbreaking decision to impose a price ceiling on the arthritis medication Enbrel. The lawsuit, filed Thursday in U.S. District Court in Denver, argues that Colorado's first-in-the-nation drug pricing regulation violates federal patent laws and constitutional protections.
Legal Challenge to Historic Price Control
The dispute centers on Colorado's October decision to set a "fair price" of approximately $31,000 per year for Enbrel, matching the price Medicare negotiated for the drug. This represents a significant reduction from the average $53,000 that insurance companies in Colorado paid for each patient using Enbrel as of 2023, with patients contributing an additional $4,600 out-of-pocket.
Amgen's complaint argues that the price ceiling conflicts with federal patent protections that allow pharmaceutical companies to charge market rates during their exclusivity period. "Congress struck a deliberate balance in the pharmaceutical arena — allowing those who develop innovative new drugs, and who can be expected to invest in new innovations, to benefit from market exclusivity for a specific and defined period while encouraging price competition thereafter," the lawsuit states.
Patent Protection Complexities
The legal battle involves complex patent considerations surrounding Enbrel, which treats six autoimmune conditions where the immune system attacks joints, skin, or other body parts. While the initial 20-year patent on Enbrel expired in 2018, Amgen has secured more than 100 additional patents since acquiring the drug from a smaller pharmaceutical company in 2002. These patents prevent generic versions from entering the U.S. market until 2029.
Constitutional and Jurisdictional Claims
Beyond patent law concerns, Amgen alleges that Colorado's pricing board violated the company's due process rights and unconstitutionally regulates transactions occurring outside the state. The lawsuit contends that while the price ceiling technically applies only to patients and companies within Colorado, it creates downward pressure on prices that pharmaceutical middlemen pay to Amgen for doses ultimately destined for Colorado residents.
Unprecedented State Action
Colorado's price ceiling represents the first time a U.S. state has imposed maximum pricing on a prescription drug, creating an uncertain regulatory landscape with unknown consequences. The state law establishing the affordability board includes provisions requiring drugmakers to provide at least six months' notice before withdrawing from the Colorado market or face a $500,000 fine.
Previous Legal Proceedings
This marks Amgen's second legal challenge to Colorado's drug pricing authority. The company filed an initial lawsuit last year after the board declared Enbrel "unaffordable," but a federal judge dismissed the case in March, ruling that Amgen had not yet demonstrated actual harm from the board's actions.
Market Impact Concerns
Amgen has issued statements suggesting that the price limit could interfere with Enbrel's availability in Colorado, though the company has not explicitly stated whether it would consider withdrawing from the state market. The Colorado Attorney General's Office declined to comment on the pending litigation.
The case represents a significant test of state authority to regulate pharmaceutical pricing and could establish important precedents for other states considering similar measures. The outcome may influence the balance between state efforts to control healthcare costs and federal protections for pharmaceutical innovation and patent rights.
