Celltrion’s Truxima Tops U.S. Rituximab Prescriptions, a First for a Korean Biosimilar

Celltrion’s blood cancer treatment Truxima (rituximab) has ranked No. 1 in prescription share in the United States, the world’s largest pharmaceutical market, the company said. It is the first such milestone for a biosimilar from South Korea.

According to IQVIA, a pharmaceutical market research firm, Truxima held a 35.8% share in the U.S. in February, based on prescription volume, placing it first.

The result comes about six years and three months after Truxima entered the U.S. market in November 2019. It has become the most-prescribed rituximab product locally, surpassing the original drug and other major global pharmaceutical products. The performance gives Truxima the distinction of being the first Korean biosimilar to lead the U.S. market by share.

Sales have also climbed. Truxima posted more than 300 billion won in revenue in North America last year, up more than 40% from the previous year, making it a key revenue driver for Celltrion.

Celltrion said the business environment has improved after the U.S. government decided to exclude biosimilars from pharmaceutical tariffs. It added that its new drug Zymfentra (the U.S. product name for Remsima SC) is also set to be produced at its Branchburg plant in the United States, a structure the company said would largely shield it from tariff effects.

Other products are also gaining traction. The autoimmune disease treatment Inflectra (infliximab) holds a 30.5% share in the United States, maintaining the highest prescription share among biosimilars, the company said. Zymfentra’s prescription volume in January rose more than threefold from a year earlier, supporting expectations for stronger synergy across the portfolio.