As U.S.-based Regeneron throws its full weight behind patent lawsuits to extend the monopoly of the macular degeneration blockbuster treatment "Eylea," launches of biosimilars by Korea's bio corporations are being blocked one after another. Although the key substance patents have already expired, Regeneron has raised the market entry bar again by ramping up legal disputes across the United States and Europe based on a formulation patent valid through 2027.
Eylea, a macular degeneration treatment co-developed by U.S.-based Regeneron and Germany's Bayer, is a representative blockbuster drug that posted $9.523 billion (about 13.3 trillion won) in global sales in 2024. Macular degeneration is a disease in which cells in the macula, the center of the retina, age and vision declines, and Eylea treats the disease by blocking the growth of new blood vessels around the macula.
According to the industry on the 16th, Regeneron has launched a multifaceted defense strategy to protect Eylea's monopoly, delaying launches by biosimilar developers, including Korea's Celltrion, a subsidiary of Samsung Bioepis Holdings, Samsung Bioepis, and Sam Chun Dang Pharm, among other corporations.
Eylea's key substance patents expired in 2024 in the United States and Korea, and in May last year in Europe. Even so, Regeneron, together with Bayer, has put forward a high-dose version of Eylea that sharply extends dosing intervals, while mounting a patent defense based on formulation and manufacturing process patents valid through June 2027. As a result, cases have continued in which actual sales are halted even after approval, drawing assessments that a "patent barrier" has been rebuilt between approval and launch.
The market where Regeneron has gone all-in on defense is the United States. As of 2024, U.S. sales of Eylea account for more than half of total revenue. Accordingly, analysis suggests Regeneron is mounting a full-spectrum patent response to keep not only Korean corporations but also global biosimilar developers such as Mylan, Formycon, and Sandoz from entering the U.S. market.
In Korea, Celltrion, Samsung Bioepis, Sam Chun Dang Pharm, and Alteogen are developing Eylea biosimilars and seeking to enter global markets.
Among them, Celltrion, which won U.S. Food and Drug Administration (FDA) approval in Oct. last year for its Eylea biosimilar "Eydenzelt," reached a settlement with Regeneron and will be able to begin U.S. sales at the end of this year. In Europe, after securing approval from the European Commission (EC) in Feb. last year, the company has been expanding launches sequentially to major countries, including the United Kingdom. However, in Germany recently, a court recognized infringement of a formulation patent and banned sales, and additional settlement talks are underway.
Samsung Bioepis also secured approvals in 2024 in the United States, Europe, and Korea for "Opuviz." In Korea, it began sales under the product name "Afilivu" through a distribution deal with Samil Pharmaceutical, but in the United States and Europe, ongoing legal disputes with Regeneron leave the specific timing of launch still uncertain.
The company is also leaving the door open to an early launch through a settlement. However, Kim Kyung-ah, president of Samsung Bioepis Holdings, said at a press briefing during the JPMorgan Healthcare Conference in San Francisco on the 14th (local time), in response to related questions, that "because this involves intellectual property (IP), it is difficult to answer publicly."
Sam Chun Dang Pharm, which applied to the FDA in Dec. last year for approval of the Eylea biosimilar "Vizenfry" with a goal of a U.S. launch this year, has also been hamstrung.
Initially, the industry expected Vizenfry could avoid patents through a separate prefilled syringe formulation technology, but Regeneron responded based on a composition and stability patent (the 865 patent), not a formulation patent. In response, Sam Chun Dang Pharm's U.S. partner Fresenius Kabi has petitioned the Patent Trial and Appeal Board (PTAB) under the U.S. Patent and Trademark Office (USPTO) to review the validity of the patent.
A company representative said, "Together with our partner Kabi, we have been pursuing a settlement for a biosimilar launch since last year," and added, "The patent litigation was a strategic choice to achieve that settlement."
Alteogen won marketing authorization for its Eylea biosimilar "Eyluxvi®" from the European Commission (EC) in Sept. last year, enabling sales in Europe. Early this month, it also filed an international patent (PCT) for a formulation technology that can address development of high-dose Eylea biosimilars. Because its low-dose approval came relatively later, the strategy is to gain an early lead with a new formulation technology that can circumvent the high-dose patents before they expire. However, a specific European launch schedule has not yet been disclosed.
At present, Amgen is the only company actually selling an Eylea biosimilar in the U.S. market. Amgen began sales in Oct. 2024 with a strategy that avoids existing patents. In response, Regeneron sued Amgen again based on new patents, and Amgen countered with an antitrust countersuit.
Regeneron's patent defense strategy is expected to continue for the time being. Among the 17 bio companies that the Trump administration asked to implement price cuts in a letter in July last year, Regeneron was the only one that did not agree.
Industry watchers say the solutions Korea's biosimilar developers choose among several options will be a watershed for the Eylea biosimilar market. An industry official said, "Whether they can enter the U.S. market is the key variable that will determine business success or failure," adding, "Amid patent offensives, each company's strategic judgment is being put to the test."