Celltrion's Truxima becomes first rituximab biosimilar to win FDA interchangeability status

Celltrion announced Tuesday that the US Food and Drug Administration has granted interchangeability status to Truxima (rituximab), its blood cancer treatment.

Truxima is the first rituximab biosimilar on the US market to receive the designation. Celltrion has also secured the exclusivity rights that accompany first-interchangeable biosimilar status.

Truxima is a blood cancer treatment developed by Celltrion. In the United States, it holds approval for all adult indications covered by the reference product, including non-Hodgkin's lymphoma, chronic lymphocytic leukemia, rheumatoid arthritis and microscopic polyangiitis.

Interchangeability status is a regulatory designation recognizing that a biosimilar can be substituted for the reference product without clinical difference in efficacy or safety. The approval officially confirms that Truxima can replace the originator drug with no meaningful clinical distinction. Celltrion said it expects the designation to strengthen prescriber confidence among US healthcare providers while improving patient access to treatment and reducing the financial burden of care.

Truxima's competitive edge is expected to hold even as the regulatory environment for biosimilars in the United States shows signs of change. Regardless of any future policy shifts, Truxima is now the only rituximab biosimilar the FDA has recognized as interchangeable — a position Celltrion said will sustain its competitive advantage in the market.

According to pharmaceutical market research firm IQVIA, Truxima held a 35.8 percent share of US rituximab prescriptions in February, ranking first. The result marks the first time a domestically developed Korean biosimilar has topped the US market by prescription volume, surpassing products from global pharmaceutical majors including the originator.

Sales figures reflect that momentum. Truxima generated more than 300 billion won ($195 million) in North American sales last year, posting growth of more than 40 percent year-on-year. Celltrion said it plans to use the interchangeability designation as a springboard to deepen its dominance in the US rituximab market and strengthen the position of its broader oncology biosimilar portfolio.

"Truxima has already proven its competitiveness by topping rituximab prescriptions in the United States, and now, by becoming the first to achieve interchangeability status, it has secured an unrivaled position in the market," a Celltrion official said. "We will do our utmost to improve patient access to treatment, backed by verified clinical data and a strong prescribing rationale."