Efficacy, Safety, and Cost-Effectiveness of the Infliximab Biosimilar GP-1111 in Patients with Inflammatory Bowel Disease Who Underwent a Nonmedical Switch: A Prospective Cohort Study

Máté Pápista,1,* Tamás Resál,1,2,* Péter Bacsur,1,3 Diána Kata,4 Bernadett Farkas,1,3 Anita Bálint,1 Anna Fábián,1 Renáta Bor,1 Emese Ivány,1 Zoltán Szepes,1 Klaudia Farkas,1,3 Zoltán Juhász,5 Norbert Buzás,5 Tamás Molnár1 1Department of Medicine, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary; 2Department of Gastroenterology, Medical Centre of the Hungarian Defense Forces, Budapest, Hungary; 3HCEMM-USZ Translational Colorectal Research Group, Szeged, Hungary; 4Department of Laboratory Medicine, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary; 5Department of Health Economics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary*These authors contributed equally to this workCorrespondence: Tamás Molnár, Department of Medicine, Albert Szent-Györgyi Medical School, University of Szeged, H-6725 Szeged, Kálvária Ave. 57, Szeged, Hungary, Tel/Fax +36-62-545-186, Email [email protected]: Data regarding treatment switch from the originator infliximab (IFX) to GP-1111 in inflammatory bowel disease (IBD) are limited. Only a few studies have examined the financial aspects of biosimilar use, none of them regarding GP-1111. The study aimed to evaluate the long-term efficacy and safety of the IFX biosimilar GP-1111 in patients with IBD who underwent a nonmedical switch from the original IFX in real-life settings. Further, it investigated the switch from a health economics perspective.Patients and Methods: A prospective cohort study was conducted on patients with IBD who were on maintenance IFX treatment and who switched to the IFX biosimilar GP-1111 due to financial constraints, with a 1-year follow-up period. Clinical and laboratory parameters were measured at baseline and at weeks 8, 16, and 52 and serum IFX levels were measured at baseline and at week 24. Statistical analyses were performed using the paired t-test, Pearson’s chi-square test, Kaplan–Meier survival curves, Cox proportional hazard regression models, and univariate linear model.Results: This study included 142 patients (95 with Crohn’s disease and 47 with ulcerative colitis). The average serum IFX level remained within the therapeutic range from baseline (3.2 ± 2.3 μg/mL) to week 24 (3.7 ± 2.7 μg/mL, p = 0.106). The corticosteroid-free remission (S-SFR) rates were stable (baseline: 69.7%, follow-up: 72.9%, p = 0.58). The 1-year treatment persistence rate was 83.1%. The adverse events included allergic reactions (IR: 6.3 per 100 patient-years) and paradoxical reactions (IR: 2.4 per 100 patient-years). Based on the estimated cost analysis, biosimilar use could lead to significant savings, with a total of 201.9 million HUF (514,000 €).Conclusion: The IFX biosimilar GP-1111 was safe and effective against IBD in real-world settings. The average serum IFX levels and S-SFR rates remained stable, while no identifiable factors leading to treatment discontinuation were observed. Biosimilar use has a cost advantage with a reassuring safety profile.Keywords: inflammatory bowel disease, infliximab, biosimilar, efficacy, safety, cost-minimization