Writing in the January 2026 edition of DIA Global Forum, Mariana Socal and Antonio J. Trujillo from the Johns Hopkins Bloomberg School of Public Health and Rachel Goode of Fresenius Kabi argue  that biosimilars could significantly reduce US drug spending and expand patient access, but that their impact is being constrained by legal and regulatory barriers rather than science.

 

Biologics treat many complex, chronic conditions. In the US, biologics account for around 2% of prescriptions but close to 50% of overall drug spending. Biosimilars, clinically equivalent but lower-cost alternatives, offer an efficient solution to reduce healthcare costs and expand access. Despite their potential, biosimilars continue to face significant regulatory and market challenges that limit their impact. In a world of escalating biologic costs, many patients are priced out. Biosimilars could offer an answer, but obstacles persist.

Two critical levers shape biosimilar competition in the US: the legal complexity of patent thickets and the regulatory designation of interchangeability. Here we offer insights that can help inform ways to improve the system so that biosimilars can be used more widely and save money for both patients and insurers.

Breaking Down Regulatory Barriers to Biosimilar Adoption

Patent Thickets: A Legal Maze Hindering Timely Access

One of the most pressing barriers to biosimilar entry is the proliferation of overlapping patents, commonly referred to as patent thickets. Compared to other countries, the US stands out dramatically. One co-author (Goode) conducted an extensive review of patent thickets and showed that litigation against the same 30 biosimilars involved 377 patents in the US versus just 24 in the UK and 46 in Canada. This disparity correlated with significantly longer times to biosimilar market launch: an average of 34 months after regulatory approval in the US compared to 4–7 months elsewhere.

A key contributor to this issue is how the US Patent and Trademark Office (USPTO) handles “obviousness-type double patenting.” By allowing terminal disclaimers (formal commitments by applicants to limit a patent’s term to the expiration date of an earlier related patent), the USPTO enables originators to file duplicative claims across multiple patents, thereby avoiding double patenting rejections. These clusters, often referred to as “rings,” inflate the scope of litigation without extending patent life, creating costly and time-consuming hurdles for biosimilar challengers.

The economic imbalance is stark. Obtaining a new drug patent typically costs between $10,000 to $50,000, but challenging a patent through litigation typically costs over $1 million. With dozens or even hundreds of overlapping patents, biosimilar developers face impractical litigation burdens that delay patient access and stifle competition.

A pragmatic reform could allow originators to file as many patents as they wish but litigate only one per duplicative cluster. This “ring representative” approach would preserve incentives for genuine innovation while streamlining litigation and accelerating biosimilar availability. By reducing legal complexity and litigation costs, this change could shorten time to market and improve affordability for patients.

This proposal is gaining traction among policymakers. The Eliminating Thickets to Increase Competition (ETHIC) Act (S.2276/H.R.3269), introduced in Congress in 2025, would limit the assertion of duplicative patents and reduce litigation burden. If enacted, it could significantly improve biosimilar competition while maintaining protections for meaningful innovation.

 

Read the full article on the DIA Global Forum website here