South Korea’s Celltrion: Truxima Tops U.S. Market, Overtaking Rituxan in Oncology

Celltrion Inc. (KRX: 068270) officially confirmed that its blood cancer therapy, Truxima (rituximab-abbs), has secured the top prescription market share in the United States. According to the February 2026 IQVIA Monthly Prescription Report, Truxima captured a 35.8% market share by prescription volume. This milestone marks the first time a biosimilar developed in South Korea has reached the number one position in a major therapeutic segment within the world’s largest pharmaceutical market.

The achievement occurs roughly six years and three months following the drug’s U.S. launch in November 2019. Truxima has now surpassed the original reference product, Rituxan, as well as competing biosimilars from global pharmaceutical giants. This rapid adoption directly influences Celltrion’s financial performance, with North American Truxima revenue exceeding 300 billion won ($198 million) in 2025—representing a 40% year-over-year increase.

Clinical Efficacy and Patient Impact

Truxima serves as a genetically engineered monoclonal antibody targeting the CD20 antigen on B-lymphocytes. In clinical settings, it provides a high-efficacy alternative for several high-mortality conditions, aligning with the World Health Organization (WHO) Global Action Plan to reduce premature mortality from non-communicable diseases by 25%. Globally, the WHO’s International Agency for Research on Cancer (IARC) identifies non-Hodgkin lymphoma (NHL) as a major public health challenge, with over 20 million new cancer cases projected globally by 2026. In the United States alone, 2026 projections estimate 79,320 new cases of NHL and 19,970 deaths.

In clinical settings, Truxima provides a high-efficacy alternative for the following conditions:

• Non-Hodgkin’s Lymphoma (NHL): Truxima treats previously untreated Stage III-IV follicular lymphoma in combination with chemotherapy. It also serves as maintenance therapy for patients responding to induction treatment.
• Chronic Lymphocytic Leukemia (CLL): Combined with fludarabine and cyclophosphamide, it treats both untreated and relapsed/refractory CLL.
• Rheumatoid Arthritis: For adults with moderate to severe active disease who have an inadequate response to TNF-inhibitors, Truxima reduces joint damage progression when paired with methotrexate.

Decoding the Evidence: Pivotal Studies and NCT Trackers

Clinical response across these indications is typically achieved within 16 to 24 weeks of initial treatment. The following trials establish the efficacy and current directives for rituximab-based therapies:

Clinical Directives and Ongoing Research

Beyond established indications, current clinical directives focus on improving administration and combination strategies:

• Maintenance Protocols: For follicular lymphoma, standard directives utilize rituximab maintenance every two to three months for up to two years to extend progression-free survival.
• PBM and Health Economics: Modern directives emphasize the use of biosimilars like Truxima (KRX: 068270) to increase patient access. In the U.S., developed nations are reporting higher cancer incidence but lower mortality due to the availability of these affordable detected and treated options.
• Synergy with Novel Agents: New trials (e.g., NCT04965493) test rituximab in “fixed duration” combinations with next-gen inhibitors like pirtobrutinib to achieve deeper molecular responses in CLL.

For patients, Truxima’s emergence as the most prescribed rituximab in the U.S. may support continued access to biologic therapies while contributing to reduced overall treatment costs in chronic cancer care.

Market Dynamics and Global Relevance

The success of Truxima signals a broader shift toward biosimilar acceptance in the U.S. healthcare system. Celltrion’s portfolio synergy remains a primary growth driver:

• Inflectra (infliximab): Currently holds the highest prescription volume among infliximab biosimilars with a 30.5% market share. It is indicated for the treatment of multiple inflammatory conditions, including Crohn’s disease, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and plaque psoriasis.
• Zymfentra (subcutaneous infliximab): As the world’s first subcutaneous infliximab, Zymfentra saw a threefold increase in monthly prescription volume in January 2026. It is specifically approved as a maintenance therapy for adults with moderately to severely active ulcerative colitis and Crohn’s disease following intravenous induction.
• Newer Launches: Steqeyma (ustekinumab), launched in early 2025, has already captured a 10.2% share due to its status as a “preferred drug” across major Pharmacy Benefit Managers (PBMs). This biosimilar is utilized to treat plaque psoriasis, psoriatic arthritis, Crohn’s disease, and ulcerative colitis.

Globally, the biotech industry is watching Celltrion’s ability to navigate U.S. trade policies. The U.S. government recently excluded biosimilars from pharmaceutical tariffs, a decision that preserves Celltrion’s core revenue stream. To further de-risk its supply chain, Celltrion is expanding its Branchburg, New Jersey facility, which it acquired from Eli Lilly. This plant will produce active pharmaceutical ingredients (APIs) for Zymfentra, shielding the product from international trade volatility and supporting Celltrion’s transition into a global Contract Development and Manufacturing Organization (CDMO).

Industry Outlook: The Biosimilar Vanguard

Celltrion’s ascent to the top of the U.S. rituximab market provides a definitive vision for international biopharmaceutical firms. It demonstrates that through rigorous clinical validation and strategic PBM partnerships, biosimilars can displace entrenched original drugs .

To appreciate the scale of Truxima’s achievement, it is essential to understand the reference product it seeks to replace. Rituxan (rituximab), developed by Biogen and Genentech (a member of the Roche Group), became the first FDA-approved monoclonal antibody for oncology in 1997. By targeting the CD20 antigen on B-cells, it established a new therapeutic pathway for B-cell malignancies.

Following patent expiry, companies such as Celltrion introduced biosimilars—lower-cost biologics that demonstrate no clinically meaningful differences in safety or efficacy through comparative trials. Truxima’s rise to the top of the U.S. market—surpassing Rituxan—confirms that a Korean-developed biosimilar can compete directly with legacy biologics in the world’s most competitive healthcare system .

Looking ahead, Celltrion has set a 2026 revenue target of 5.3 trillion won, supported by a pipeline of 41 biosimilars and upcoming launches including Omlyclo (omalizumab) and Avtozma (tocilizumab). The Incheon-based company aims to cement its status as a dominant force in both the autoimmune and oncology sectors. This performance confirms that the “Korean Biotech” label is no longer just emerging—it is leading the global life sciences market.

Author

Bernice Lottering