The therapeutic landscape for inflammatory bowel disease (IBD) is evolving at a rapid pace. Consequently, healthcare professionals require a standardized IBD therapy nomenclature to ensure patient safety and effective communication. Since 1953, the World Health Organization (WHO) has utilized the International Nonproprietary Name (INN) system to assign unique identities to medicines. However, the explosive growth of monoclonal antibodies has recently outgrown the utility of the traditional "-mab" suffix.

Historically, the "-mab" suffix served as a universal identifier for all monoclonal antibodies. Furthermore, this system provided a simple way for clinicians to recognize biological therapies. As drug engineering became more sophisticated, however, the old system failed to distinguish between various structural formats. Therefore, in late 2021, the WHO International Nonproprietary Name expert group introduced four new suffixes to enhance clarity.

The Shift in IBD Therapy Nomenclature

The updated framework replaces "-mab" with four distinct stems: "-tug", "-bart", "-ment", and "-mig". Specifically, these suffixes categorize therapies based on their protein structure and functional design. For instance, "-tug" identifies unmodified, full-length immunoglobulins. In contrast, the suffix "-bart" describes artificial or engineered immunoglobulins that possess modified constant regions. Additionally, "-ment" refers to immunoglobulin fragments, while "-mig" designates multi-specific immunoglobulins.

Moreover, these changes are critical for international pharmacovigilance. Because many new IBD therapies fall into these categories, clinicians must become familiar with the updated terms. Properly identifying these agents helps avoid prescribing errors and facilitates better communication across borders. Notably, these new naming rules only apply to new drugs; existing therapies like infliximab will retain their current names.

In summary, understanding the evolving IBD therapy nomenclature is essential for modern clinical practice. As biologic therapies continue to diversify, these precise names will support safer medication management. Therefore, staying informed about WHO updates ensures that clinicians remain at the forefront of IBD care.

Frequently Asked Questions

Will the names of existing IBD biologics like adalimumab change?

No, the updated WHO INN nomenclature rules only apply to new therapies introduced after the 2021 reform. Existing drugs will maintain their current "-mab" names to prevent confusion in clinical practice.

What is the difference between a -tug and a -bart suffix?

A "-tug" suffix indicates an unmodified, monospecific, full-length immunoglobulin. Conversely, a "-bart" suffix signifies a monospecific full-length immunoglobulin that has undergone artificial engineering or amino acid changes in its constant regions.

Disclaimer: This content is for informational and educational purposes only. It does not constitute medical advice or a professional relationship. Refer to the latest local and national guidelines for clinical practice.

References

1. Colwill M et al. Nomenclature of therapies in inflammatory bowel disease: A journey through time and terminology. Inflamm Bowel Dis. 2026 Feb 11. doi: undefined. PMID: 41671047.

2. World Health Organization. New INN nomenclature scheme for monoclonal antibodies (mAb). Geneva: WHO Press; 2022.

3. Raybould M. New Antibody Therapeutic INNs will no longer end in “-mab”! Oxford Protein Informatics Group. Published January 14, 2022.