FDA to Waive Clinical Efficacy Studies for Monoclonal Antibody Biosimilars

The FDA has announced it will waive clinical efficacy studies (CESs) for monoclonal antibody biosimilars. This decision, according to a news release, would fundamentally redefine how these drugs will be developed, approved, and made affordable for patients, making it a groundbreaking milestone for both pharmaceutical innovation and health care.¹

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Biosimilars are biologic medications that are highly similar to biologics—such as adalimumab (Humira; AbbVie), dupilumab (Dupixent; Regeneron Pharmaceuticals), and pembrolizumab (Keytruda; Merck)—without having clinically meaningful differences from their reference product. Oftentimes, they are made with the same types of living sources and given to patients via the same mode of administration. They also have similar formulations and strengths and the same doses and treatment benefits while offering patients more affordable treatment options. Despite the active ingredients in generic drugs often being smaller, simpler, and easier to copy, biologics cannot be copied exactly.^2,3

Biosimilars are identifiable by the 4-letter distinguishing suffix attached to the drug name. These are FDA-mandated because biosimilars must have the same core name as their reference product while also remaining identifiable. Because the product does not need to demonstrate superiority to its reference product—but instead biosimilarity or clinical similarity—the biosimilar approval process is shorter. Rather, the goal of these trials is to identify that the investigational treatment is similar to its reference product, moves through patients similarly, and is produced and structured in a similar fashion.²

According to the news release, CESs have been a significant and costly aspect of the biosimilar approval process, despite their inability to demonstrate meaningful failure outcomes. Sarfaraz K. Niazi, adjunct professor at the University of Illinois at Chicago and founder of multiple biopharmaceutical enterprises, persistently argued that CESs add no scientific value to biosimilar evaluation, because both analytical similarity and immunogenicity studies are sufficient to confirm biosimilarity of products.¹

Further, Niazi's biosimilar application for Stelara (ustekinumab) will be the first filed with the FDA that does not require any clinical testing, marking a precedent-setting regulatory breakthrough. The removal of CES requirements is expected to accomplish the following¹:

• Reduce biosimilar development costs by over 90%
• Accelerate approval timelines by more than 70%
• Empower small- and mid-sized companies to enter the biosimilar market, where entry had previously been limited to resource-rich pharmaceutical giants
• Spur competitive pricing that mirrors the trajectory of generic small-molecule drugs, delivering widespread affordability to patients

Notably, this decision aligns the FDA with the European Medicines Agency and the United Kingdom’s Medicines and Healthcare Products Regulatory Agency, which have already taken steps that are in line with Niazi's recommendations. With harmonization across regulatory jurisdictions, the pathway to global biosimilar approvals is becoming clearer and more feasible than it previously had.¹

"This is not just my victory. This is a victory for science, for reason, and most importantly, for patients who deserve affordable access to biological medicines,” Niaz explained in the news release. “The FDA's acceptance ushers in a new era where innovation is not held hostage by outdated testing requirements. It will fundamentally reshape the economics of biosimilars and expand access globally.”¹

REFERENCES

1. PR Newswire. Professor Sarfaraz K. Niazi Secures First-Ever FDA Acceptance to Waive Clinical Efficacy Studies for Monoclonal Antibody Biosimilars. News release. September 1, 2025. Accessed September 2, 2025. https://www.prnewswire.com/news-releases/professor-sarfaraz-k-niazi-secures-first-ever-fda-acceptance-to-waive-clinical-efficacy-studies-for-monoclonal-antibody-biosimilars-302542781.html

2. McGovern G. Understanding Biologics and Biosimilars Amid an Evolving Treatment Landscape. Pharmacy Times. June 12, 2025. Accessed September 2, 2025. https://www.pharmacytimes.com/view/understanding-biologics-and-biosimilars-amid-an-evolving-treatment-landscape

3. US Food & Drug Administration. Biosimilars Basics for Patients. Updated August 1, 2024. Accessed September 2, 2025. https://www.fda.gov/drugs/biosimilars/biosimilars-basics-patients