P473 Long-term follow-up of switching from original adalimumab to adalimumab biosimilar: real-world data in IBD
C. Padilla Suarez, K. Webb, N. Persad, J. Sercombe, E. Tyler, K. Klimova
Gastroenterology, University Hospitals Plymouth NHS Trust, Plymouth, UK
Background
Studies have reported good efficacy outcomes for patients with inflammatory bowel disease (IBD) treated with biosimilars. There are limited long-term data. We assessed the long-term efficacy data and safety after switching from adalimumab to adalimumab biosimilars in patients with IBD.
Methods
A prospective single-centre observational study involving patients with Crohn’s disease or ulcerative colitis switched from adalimumab to adalimumab biosimilar and reviewed up to 12months. Efficacy and loss of response were measured using the Harvey–Bradshaw (HB) index and partial Mayo score for patients with Crohn’s disease and ulcerative colitis respectively. Blood tests including C-reactive protein, adalimumab drug levels and anti-drug antibodies were monitored. We have recorded side effects and possible serious adverse effects. The plan is to continue the study for 24 months.
Results
109 patients with IBD have completed at least 6 months of treatment with adalimumab biosimilar, 12 of which have ulcerative colitis and 97 Crohn’s disease. Most of them (88%) continued on biosimilar after 6 months. Patients discontinued the therapy due to loss of response or development of antibodies in one case. Two patients were switched to a different biosimilar due to the presence of side effects which were however not serious. Of those who remained on the treatment, 74.5% were in clinical remission at 6 months and 71.4% at 9 months. HB index, partial Mayo score, C-reactive protein and adalimumab drug levels did not show significant changes. We have not reported any serious adverse events. We hope than by February, at least 60% of these patients will have been on Adalimumab for 12 months and further amended date would be added.
Conclusion
Most of the patients switching from original adalimumab were maintained on biosimilar at 6 and 12months of follow-up with similar efficacy and safety as the original drug.