P938 Effectiveness and safety of switching from original infliximab to GP1111 biosimilar in inflammatory bowel diseases – prospective, cohort study

Abstract

Abstract Background Biosimilars are highly similar to the already approved reference biological medication, and are potentially more accessible widespread due to the better cost-effectiveness. However, both the effectiveness and immunogenicity may differ due to structure characteristics. In 2020, non-medical switch was obligated from originator infliximab (IFX) to biosimilar GP1111 amongst inflammatory bowel disease (IBD, Crohns’s disease [CD], ulcerative colitis [UC]) patients in Hungary. As data regarding GP1111 are lacking in IBD, thus we aimed to assess the pharmacokinetics, effectiveness and safety of biosimilar GP1111 following the financial switch. Methods This was a real-world, prospective, single-center cohort study enrolling IBD patients who were switched from original IFX to GP1111 biosimilar. Baseline was defined as the day of the switch, and 52 weeks of follow-up was set. Demographic and clinical data were recorded at w0, w8, w16, w24, and w52, while infliximab serum levels were measured at baseline and at w52. Primary outcome was change in serum trough level of IFX, while sustained steroid-free remission, loss of response rates and adverse events were secondary outcomes. Results Overall, data of 142 patients were analyzed (median age: 43.1 years [IQR: 32.3 - 49.6]; male/female ratio: 77/65; CD: 97, UC: 42). Mean follow-up period was 46.2 ± 10.3 weeks. Change in serum IFX level was not observed (baseline 3.2 ± 2.3, µg/mL; w24: 3.7 ± 2.7 µg/mL; p = 0.106). Sustained steroid-free remission rates did not alter at w52 (99/142) from baseline (86/142) (p = 0.11). Overall, treatment was ceased in 24 patients. Following dose escalation and intensification, 9/18 patients discontinued treatment due to loss of response. Further treatments were ceased in 15 patients due to allergy (8), paradoxical reactions (3), malaise (1), pregnancy (1), and non-compliance (2). At w52 83.1% of the patients were on drug, and treatment persistence was not associated with the length of prior IFX treatment period. Conclusion Our study revealed convincing effectiveness with reassuring safety profile of switching to GP1111 in long-term, with sustained IFX levels. The usage of this particular biosimilar in daily practice may be suggested.