Aims: Ocrelizumab is a humanized anti-CD20 monoclonal antibody used in multiple sclerosis. Since its commercialization, several cases of ocrelizumab-induced colitis have been reported in the scientific literature.
Methods: To explore the potential association of ocrelizumab with colitis as an adverse drug reaction (ADR), we conducted a descriptive and disproportionality analysis of ocrelizumab-induced colitis registered in VigiBase, as well as an extensive literature review and a description of two cases from Luxembourg reported to our pharmacovigilance centre.
Results: Our VigiBase analysis revealed 400 cases of ocrelizumab-induced colitis, with 79.0% serious cases and a median time to onset of 17 months. The preferred term (PT) coded was 'colitis' (53.0%), followed by PTs related to inflammatory bowel diseases (33.5%). Significant disproportionality was found for high-level term 'colitis' and for 'colitis', 'colitis microscopic' and 'immune-mediated enterocolitis' PTs. Our literature review revealed 24 case reports corresponding to 36 patients with a median time to onset of 18 months and a predominance of unspecified colitis (61.1%) and inflammatory bowel diseases (27.8%). Two patients relapsed after ocrelizumab resumption.
Conclusions: Together, our findings of two relevant clinical cases of ocrelizumab-induced colitis, the literature review and the significant VigiBase disproportionality, suggest a potential safety signal for ocrelizumab.
Keywords: adverse drug reaction; colitis; disproportionality analysis; ocrelizumab; pharmacovigilance.
© 2026 The Author(s). British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.