POS0812 DRUG RETENTION RATE OF TNFi BIO-ORIGINALS AND BIOSIMILARS IN axSpA AND PsA IN ROUTINE RHEUMATOLOGY CARE IN GERMANY
Authors: A. Regierer, A. Weiß, F. Behrens, M. Worsch, K. Pagel, G. Schett, A. Strangfeld
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> TNFi biosimilars (BS) are increasingly being used in axSpa and PsA in Germany after their marketing authorization. Regulatory approval is based on a totality-of-evidence approach that involves analytical studies followed by confirmatory clinical studies to show equivalence with the bio-original (BO). Real-world data regarding drug retention rates in axSpA and PsA are sparse. <h3>Objectives:</h3> A comparative analysis on drug retention rate between TNFi BO and their BS in axSpA and PsA in routine rheumatology care in Germany. <h3>Methods:</h3> RABBIT-SpA is a prospective longitudinal cohort study including axSpA and PsA patients enrolled at start of a new conventional or bDMARD/tsDMARD treatment. All patients with a documented initiation of first-line TNFi treatment in RABBIT-SpA were included in this analysis. Descriptive statistics were used to compare patients treated with etanercept BO with etanercept BS, and adalimumab BO with adalimumab BS as first-line including the reasons for treatment discontinuation. Drug retention was compared using drug survival analysis. Reasons for treatment discontinuation (including non-medical switch) other than lack of effectiveness were considered censoring events. <h3>Results:</h3> 771 axSpA and 620 PsA patients were included in the analysis. Baseline characteristics were comparable between BO and BS treated patients (Table 1). The proportion of axSpA patients reaching ASDAS low disease activity (ASDAS≤2.0) at 6 months was 59%/77% with etanercept BO/etanercept BS and 66%/59% with adalimumab BO/adalimumab BS. The proportion of PsA patients reaching DAPSA low disease activity (DAPSA≤14) at 6 months was 73%/57% with etanercept BO/etanercept BS and 61%/64% with adalimumab BO/adalimumab BS. In BO treated patients, 51% switched to BS due to non-medical reasons. After censoring for these non-medical switches, drug retention rates were similar between BO and BS, in axSpA and PsA and for etanercept and adalimumab (Figure 1a and b). <h3>Conclusion:</h3> Drug retention was very similar between BO and BS in axSPA and PsA patients receiving first-line TNFi. Results are in line with data from the clinical trials. These findings support the equivalence of BO and their respective BS. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> Anne Regierer Speaker fees Amgen, BMS, Novartis, Pfizer, Roche, None personal; RABBIT-SpA is supported by a joint, unconditional grant from AbbVie, Amgen, Biogen, Celltrion, Hexal, Janssen-Cilag, Lilly, MSD, Novartis, Pfizer, UCB and Viatris., Anja Weiß none personal; RABBIT-SpA is supported by a joint, unconditional grant from AbbVie, Amgen, Biogen, Celltrion, Hexal, Janssen-Cilag, Lilly, MSD, Novartis, Pfizer, UCB and Viatris, Frank Behrens: None declared, Matthias Worsch: None declared, Katharina Pagel: None declared, Georg Schett: None declared, Anja Strangfeld Speaker fees AbbVie, Biogen, Galapagos, Janssen, Lilly, Pfizer, Takeda., None personal; RABBIT-SpA is supported by a joint, unconditional grant from AbbVie, Amgen, Biogen, Celltrion, Hexal, Janssen-Cilag, Lilly, MSD, Novartis, Pfizer, UCB and Viatris.