The U.S. Food and Drug Administration (FDA) has expanded its roster of approved biosimilars with two recent additions to the ustekinumab class. Biocon's Yesintek (ustekinumab-kfce) received approval on November 29, 2024, followed by Celltrion's Steqeyma (ustekinumab-stba) on December 17, 2024. These approvals bring the total number of FDA-approved biosimilars to 65 across five major product classes.
Both Yesintek and Steqeyma are biosimilars to Janssen's Stelara (ustekinumab), indicated for the treatment of Crohn's disease, plaque psoriasis, psoriatic arthritis, and ulcerative colitis. These approvals represent significant additions to the growing arsenal of biosimilar options for patients with autoimmune conditions.
The Growing Biosimilar Landscape
The FDA's biosimilar approval pathway was established through the Biologics Price Competition and Innovation (BPCI) Act, part of healthcare reform legislation signed into law by President Barack Obama on March 23, 2010. This pathway allows for expedited approval of biological products demonstrated to be "highly similar" or "interchangeable" with an FDA-licensed reference product.
Since the approval of the first U.S. biosimilar, Zarxio (filgrastim-sndz) in 2015, the FDA has approved biosimilars across five major product classes:
- Insulin
- Granulocyte colony-stimulating factors
- Monoclonal antibodies
- Tumor necrosis factor-alpha (TNF-α) inhibitors
- Vascular endothelial growth factor (VEGF) inhibitors
Dr. Sarah Yim, Director of the Office of Therapeutic Biologics and Biosimilars at the FDA's Center for Drug Evaluation and Research, noted in a recent statement: "The continued expansion of biosimilar options represents a significant advancement in our efforts to provide patients with more affordable access to important biological therapies."
Interchangeable Biosimilars: A Growing Subset
Of the 65 approved biosimilars, 14 have received the coveted interchangeable designation. This designation is particularly significant as it allows pharmacists to substitute the biosimilar for the reference product without intervention from the prescribing healthcare provider—similar to how generic drugs can be substituted for brand-name small molecule drugs.
The interchangeable biosimilars currently approved include:
- Abrilada (adalimumab-afzb)
- Bekemv (eculizumab-aeeb)
- Byooviz (ranibizumab-runa)
- Cimerli (ranibizumab-eqrn)
- Cyltezo (adalimumab-adbm)
- Hyrimoz (adalimumab-adaz)
- Jubbonti (denosumab-bddz)
- Opuviz (aflibercept-yszy)
- Rezvoglar (insulin glargine-aglr)
- Semglee (insulin glargine-yfgn)
- Simlandi (adalimumab-ryvk)
- Wezlana (ustekinumab-auub)
- Wyost (denosumab-bddz)
- Yesafili (aflibercept-jbvf)
Additionally, two biosimilars have received provisional determination on interchangeability: Samsung Bioepis' Pyzchiva (ustekinumab-ttwe) and Sandoz's Enzeevu (aflibercept-abzv).
The first interchangeable biosimilar approved in the U.S. was Semglee (insulin glargine-yfgn) on July 28, 2021, marking a significant milestone in the evolution of the biosimilar market.
Market Impact and Patient Access
The growing number of biosimilar approvals has significant implications for healthcare costs and patient access. Biosimilars typically enter the market at prices 15-35% lower than their reference products, potentially generating substantial savings for the healthcare system.
"The introduction of biosimilar competition has already begun to shift the market dynamics for biological products," explained healthcare economist Dr. Robert Miller of the Center for Healthcare Economics. "As more biosimilars enter the market, particularly those with interchangeable status, we expect to see continued downward pressure on prices and improved patient access to these critical therapies."
For patients with conditions like Crohn's disease, ulcerative colitis, and psoriasis, the approval of ustekinumab biosimilars could translate to more affordable treatment options. The average annual cost of Stelara treatment can exceed $70,000, making cost-saving alternatives particularly valuable.
Unique Naming Convention
The FDA has implemented a specific naming convention for biosimilars to ensure accurate product identification and pharmacovigilance. All approved biosimilars receive a non-proprietary name that includes a four-letter suffix attached to the core name with a hyphen. This naming system helps distinguish between biological products that may not be interchangeable.
For example, the recently approved ustekinumab biosimilars are designated as ustekinumab-kfce (Yesintek) and ustekinumab-stba (Steqeyma), clearly differentiating them from the reference product and from each other.
Looking Ahead: The Future of Biosimilars
The biosimilar market in the United States continues to evolve, with numerous products in development across multiple therapeutic areas. Industry analysts predict that the next wave of biosimilar approvals will target high-value biologics in oncology and immunology.
"We're still in the early stages of biosimilar market development in the U.S.," noted pharmaceutical industry analyst Maria Chen. "While Europe has a more mature biosimilar market, the U.S. is catching up quickly, with increasing acceptance among providers, payers, and patients."
As the biosimilar landscape continues to expand, stakeholders across the healthcare system are adapting to this new reality. Manufacturers of reference products are implementing various strategies to maintain market share, including developing next-generation products and offering competitive contracting terms to payers.
For patients and healthcare providers, the growing availability of biosimilars represents an opportunity to balance clinical needs with cost considerations, potentially expanding access to critical biological therapies for more patients who need them.
With the recent approvals of Yesintek and Steqeyma, the biosimilar market takes another step forward in its evolution, promising continued growth and increased competition in the years ahead.
