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P330 Long-term outcomes following a switch from originator adalimumab to the biosimilar SB5 (Imraldi) in IBD

Derikx, L.(1,2);Dolby, H.(2);Plevris, N.(2);Lucaciu , L.(2);Rees, C.(2);Lyons, M.(2);Siakavellas, S.(2);Constantine-Cooke, N.(3);Noble, C.(2);O’Hare, C.(2);Merchant, L.(2);Arnott, I.(2);Jones, G.R.(2,4);Lees, C.(2,5);

(1)Radboud University Nijmegen Medical Centre, Inflammatory Bowel Disease Centre- Department of Gastroenterology and Hepatology- Route 455, Nijmegen, The Netherlands;(2)Western General Hospital, Edinburgh IBD Unit, Edinburgh, United Kingdom;(3)University of Edinburgh- Western General Hospital, MRC Human Genetics Unit- Institute of Genetics and Molecular Medicine-, Edinburgh, United Kingdom;(4)University of Edinburgh, Centre for Inflammation Research- The Queen's Medical Research Institute, Edinburgh, United Kingdom;(5)University of Edinburgh- Western General Hospital, Centre for Genomics and Experimental Medicine- Institute of Genetics and Molecular Medicine, Edinburgh, United Kingdom

Background

Multiple adalimumab (ADA) biosimilars, including SB5 (Imraldi) and ABP 501 (Amgevita), are now approved for use in IBD. Data about biosimilar ADA in IBD remain scarce. We therefore aimed to investigate long-term outcomes of the biosimilar SB5 in IBD patients following a switch from the ADA originator (Humira) or after start of SB5 as their first ADA-therapy.

Methods

We performed a retrospective cohort study in a tertiary IBD referral centre. All IBD patients treated with Humira underwent an elective switch to SB5 regardless of IBD phenotype, disease activity and ADA dosing. All patients were reviewed regularly in the virtual biologics clinic with protocol driven collection of clinical disease activity, blood tests, TDM and faecal calprotectin. We identified all patients on SB5 in a biologic prescription database that prospectively registered all ADA by brand name and start and stop dates.

Results

441 patients were treated with SB5, including 234 who switched from Humira to SB5 (CD=209, 89.3%; median IBD duration 10 years, IQR 6-16) and 207 who started on SB5 as their first ADA-therapy (CD=162, 78.3%; median IBD duration 6 years, IQR 1-16.8).

107/234 (45.7%) patients who switched to SB5 used infliximab before ADA. These patients were treated for a median of 32 months (IQR 17-57) with Humira prior to switching. At Humira – SB5 switch, 60.1% (140/234) received 40mg ADA every other week and 39.1% (91/234) once weekly. The median duration of follow up was 13 months (IQR 8-14). At week 26 and week 52, 194/231 (84.1%) and 148/215 (70.3%) patients remained on SB5, respectively (Figure 1). 81/234 patients (35.0%) discontinued SB5, mostly due to adverse events (n=40/81) or secondary loss of response (n=35/81). Pain at the injection site was the most frequently reported adverse event (n=31); all these patients switched to Amgevita. 30/31 patients with a double biosimilar continued Amgevita until the end of follow up (median 30 months), resulting in 172/215 (81.3%) patients that remained on ADA at week 52 (Figure 1).

Proportions of patients in biochemical remission and clinical remission were similar at baseline, week 26 and week 52 following switch (Figure 2). Median ADA trough levels were similar before (10.2 ug/ml, IQR 7.4-13.5) and after switch 10.3 (IQR 7.4-13.1). 17/234 (7.3%) patients developed antibodies during SB5 treatment.

Figure 1

Figure 2

Conclusion

Switching from Humira to SB5 appeared effective and safe in this study with over 12 months of follow up. The most common adverse event was injection site pain; these patients were successfully moved on to Amgevita providing the first data about a double biosimilar switch. Over the 24 months of this biosimilar ADA program substantial cost savings were effected.

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