UCB presented new EULAR 2026 data showing rheumatoid factor (RF) binds Fc‑containing TNF inhibitors but not Fc‑free CIMZIA® (certolizumab pegol), supporting consistent efficacy across RF levels in rheumatoid arthritis and reinforcing recent EU and UK label updates.
Written By: Farha Farheen, PharmD
Reviewed By: Pharmacally Editorial Team
UCB presented new data at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress showing that rheumatoid factor (RF) binds Fc-containing TNF inhibitors but not Fc-free CIMZIA® (certolizumab pegol), providing a potential explanation for the drug’s consistent efficacy across RF levels in rheumatoid arthritis (RA).
The findings coincide with recent European Union and UK label updates that recognize CIMZIA’s distinct Fc-free mechanism.
The in vitro and electron microscopy data demonstrated that RF binds to Fc-containing biologics, triggering immune complex formation and inflammatory cytokine release. In contrast, certolizumab pegol showed no RF binding, no immune complex formation, and no downstream inflammatory activation. The findings provide mechanistic evidence supporting previously reported clinical outcomes with CIMZIA across different RF subgroups.
Clinical Correlation
The mechanistic findings align with earlier observations from CIMZIA’s RA clinical program, including the RAPID studies, which demonstrated consistent efficacy in both RF-positive and RF-negative patients. Elevated RF levels remain common in clinical practice and are associated with more severe disease and poorer outcomes.
Approximately one-quarter of patients receiving biologic therapies have high RF levels, which have been linked to lower drug exposure and reduced responses to Fc-containing TNF inhibitors such as adalimumab. Because CIMZIA lacks an Fc region, it avoids RF-mediated immune complex formation and macrophage clearance, potentially helping maintain treatment exposure and clinical effectiveness regardless of RF status.
Regulatory Updates
UCB noted that the new findings are reflected in recent updates to the European Union Summary of Product Characteristics (SmPC) and UK prescribing information. Both documents now state that CIMZIA is not bound by RF, does not form RF-mediated immune complexes, and is not subject to RF-dependent macrophage clearance in vitro.
The label revisions further distinguish certolizumab pegol from Fc-containing TNF inhibitors and provide regulatory recognition of the mechanism highlighted by the new EULAR data.
Expert Perspectives
Dr. James Galloway, Professor of Rheumatology at King’s College London and Honorary Consultant Rheumatologist at King’s College Hospital, said RF influences treatment outcomes beyond its traditional role as a diagnostic marker. He noted that the new findings help explain treatment variability among patients with elevated RF levels and support more informed treatment selection in clinical practice.
Donatello Crocetta, Chief Medical Officer and Global Head of Medical Affairs at UCB, said the data reinforce the company’s commitment to generating evidence that supports personalized treatment approaches for immune-mediated diseases. He added that the EULAR findings and recent label updates further strengthen the scientific differentiation of CIMZIA in rheumatoid arthritis.
Strategic Context
The RF findings were among 27 UCB abstracts presented at EULAR 2026 across the company’s immunology portfolio, including rheumatoid arthritis, psoriatic arthritis, psoriasis, axial spondyloarthritis, and systemic lupus erythematosus.
By clarifying the biological mechanisms behind CIMZIA’s consistent efficacy across RF levels, the data support the growing role of biomarker-informed treatment selection in rheumatoid arthritis and further strengthen the therapy’s clinical positioning among patients with elevated RF.
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About the Writer
Farha Farheen, PharmD (LinkedIn) is a pharmacy professional with a strong interest in pharmacovigilance and clinical research. She has completed her Doctor of Pharmacy (Pharm.D) along with her internship as a Clinical Pharmacist. She has hands-on experience in adverse drug reaction (ADR) reporting, safety data documentation, and pharmacovigilance workflows, and is proficient in using VigiFlow. She is also a patent holder for an antibacterial formulation enriched with bioactive substances, granted by the German Patent and Trademark Office.