Regeneron Faces New Rival as FDA Approves Eylea Competitor
Celltrion's Eydenzelt, a biosimilar to Regeneron's blockbuster eye drug, has received US regulatory approval, intensifying competition.
Regeneron Pharmaceuticals (REGN) is facing intensified competition for its top-selling eye medication, Eylea, after the U.S. Food and Drug Administration (FDA) approved a biosimilar competitor. South Korean pharmaceutical company Celltrion announced it has received , paving the way for a lower-cost alternative to enter the lucrative market for treating retinal diseases.
The approval represents a significant challenge to one of Regeneron's primary revenue sources. Eylea, used to treat conditions like wet age-related macular degeneration and diabetic macular edema, has been a blockbuster drug for the company for years. However, the franchise is already under considerable pressure. amid rising competition, with sales falling 25% in the second quarter of 2025 alone.
The entrance of Eydenzelt is expected to accelerate this trend. Biosimilars are highly similar, and often cheaper, versions of biologic drugs that have lost their patent exclusivity. Their availability typically leads to price erosion and market share loss for the original drug manufacturer. The market for Eylea biosimilars is already active, with Amgen's Pavblu having launched earlier in the year and other competitors expected to follow.
Regeneron's strategy to defend its Eylea franchise has centered on transitioning patients to Eylea HD, which offers less frequent dosing. While Eylea HD has seen sales growth, it has not been enough to fully offset the sharp decline of the original formula. The company also faced a recent setback when the , a development that could hinder its competitiveness against rival treatments like Roche's Vabysmo.
While the erosion of Eylea sales poses a headwind, Regeneron's overall financial health is supported by a diversified portfolio. The company has seen strong performance from its immunology drug Dupixent, which continues to post robust double-digit sales growth. Investors will be closely watching how effectively Regeneron can manage the decline of its flagship eye drug while capitalizing on growth from other areas of its business.