Regeneron Awarded Injunctions Blocking Eylea Biosimilars

Regeneron Pharmaceuticals has secured a series of legal victories barring recently FDA approved biosimilars to its blockbuster eye drug, Eylea®, from hitting shelves until 2027.

On June 11 and June 14, 2024, Chief Judge Thomas S. Kleeh of the U.S. District Court for the Northern District of West Virginia granted the injunctions against Eylea biosimilars Yesafili® (Biocon Biologics; Bengaluru, India) and Opuviz® (Samsung Bioepis; Incheon, South Korea). 

These rulings come on the heels of temporary restraining orders issued last month, rescuing Regeneron’s exclusivity in the US aflibercept 2mg market. They also follow FDA approval of the drugs just 3 weeks earlier.

The court’s decisions hinge on claims of patent infringements by Eylea biosimilars. In December 2023, the court found that Biocon’s Yesafili, an interchangeable biosimilar, infringed several treatment method claims of Regeneron’s U.S. Patent No. 11,084,865.1 

Despite these victories, Regeneron’s legal campaign looks to be just getting started. The company is seeking injunctions against other biosimilars that have yet to gain FDA approval such as Eydenzelt® (Celltrion; Incheon, South Korea), ABP 938 (Amgen; California, USA), and FYB203 (Formycon; Planegg, Germany). The temporary restraining orders currently blocking these potential launches are set to expire soon, with decisions on injunctions expected.

Samsung Bioepis and Biocon also have the option to appeal the district court’s decisions, potentially extending legal proceedings. After filing a notice of appeal and appeal brief with the Patent Trial and Appeal Board (PTAB), the patent examiner then has three choices: reopen the prosecution to introduce a new rejection, withdraw the rejection and allow the claims, or maintain the rejection and submit an answer to the appeal. If the rejection stands, the biosimilar manufacturers will have to respond with a reply brief and can request an oral hearing before the PTAB, which will then decide the appeal.

Should the PTAB rule against them, Samsung Bioepis and Biocon can either appeal directly to the U.S. Court of Appeals for the Federal Circuit or file a civil action against the Director of the PTAB in the U.S. District Court for the District of Columbia.

A pharmaceutical powerhouse

Eylea, also known by its generic name aflibercept, is a medication primarily used in the treatment of various retinal diseases. It is an anti-VEGF (vascular endothelial growth factor) therapy, which works by inhibiting the growth of abnormal blood vessels in the retina and reducing fluid leakage. This mechanism helps in managing and treating conditions that lead to vision loss.

Aflibercept is used to treat several eye conditions, including wet age-related macular degeneration (AMD), diabetic macular edema (DME), retinal vein occlusion (RVO), diabetic retinopathy (DR) and retinopathy of prematurity (ROP).

The market for Eylea is expected to expand from $7.8 billion in 2023 to $8.19 billion in 2024, with a compound annual growth rate (CAGR) of 5.1%. This rise in demand for Eylea is driven by several factors: the increasing prevalence of retinal diseases, Eylea’s strong clinical and safety record, and a significant shift towards using intravitreal injections for managing retinal disorders.2-4

Eylea’s stronghold on the aflibercept market is lucrative, making it a tempting target for biosimilar manufacturers. Regeneron’s recent court victories underscore the complexities and high stakes involved in the pharmaceutical industry, particularly in ophthalmology. As the company pursues further legal action against other biosimilars, the landscape of retinal disease treatments remains dynamic.


  1. Regeneron v. Mylan, 1:22-CV-61 (N.D.W. Va). Available at: Accessed on June 16, 2024.
  2. The Business Research Company. Eylea Global Market Report 2024. Research and Markets. 2024. Available at: Accessed on June 16, 2024. 
  3. Rosenblatt TR, Vail D, Saroj N, et al. Increasing incidence and prevalence of common retinal diseases in retina practices across the United States. Ophthalmic Surg Lasers Imaging Retina. 2021;52(1):29-36.
  4. Lam LA, Mehta S, Lad EM, et al. Intravitreal injection therapy: Current techniques and supplemental services. J Vitreoretin Dis. 2021;5(5):438-447.
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