POS0095 SAFETY OF BIOSIMILAR ETANERCEPT GP2015 IN PATIENTS WITH RHEUMATOID ARTHRITIS: RESULTS FROM A UK-BASED REGISTRY STUDY
Authors: C. R. Holroyd, S. Earl, C. Both, C. Salvati
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> It is important to assess the long-term safety of biologic medicines in routine clinical practice to monitor for unexpected adverse events (AEs) and the real-world incidence of known AEs. <h3>Objectives:</h3> The aim of this analysis was to investigate long-term safety of GP2015, an approved etanercept (ETN) biosimilar, versus conventional-synthetic (cs) disease-modifying antirheumatic drugs (DMARDs) or other anti-tumor necrosis factors (anti-TNFs) in patients with rheumatoid arthritis (RA) in routine clinical practice in the UK. <h3>Methods:</h3> These data were generated in the British Society for Rheumatology Biologics Register for RA (BSRBR-RA) study and provided for the purpose of pharmacovigilance. Patients in the UK with RA who received a csDMARD (2002–2009) or anti-TNF (2010 onwards [GP2015: 2017 onwards]) could be recruited into the BSRBR-RA study. Patients in the anti-TNF cohort (excluding those treated with GP2015) were biologic-naïve, whereas patients in the GP2015 cohort were biologic-naïve or switched from reference ETN (ETN-experienced) or another biologic (biologic-experienced). Data collected included changes to anti-rheumatic therapies, disease activity, and AEs. The rates of first event per 1000 person-years with 95% confidence interval (CI) were calculated for the GP2015, csDMARD, and anti-TNF cohorts, with data censored at time of first event. The time to first event was compared for GP2015 versus csDMARDs and versus anti-TNFs using Cox-proportional hazards models (calculated separately for each comparison). Hazard ratios (HRs) were adjusted using baseline variables, including number of comorbidities and previous DMARD exposure. Missing baseline data were addressed using multiple imputation. For the anti-TNF and GP2015 cohorts, the exposure window for serious AEs (SAEs), excluding malignancies, was from treatment initiation to 90 days post-treatment, date of last follow-up, death, or cut-off date (May 31, 2022), whichever occurred first; for malignancies, the exposure window was from treatment initiation to death or cut-off date. For the csDMARD cohort, the exposure window for SAEs, excluding malignancies, was from study entry to death, date of last follow-up, cut-off date, or start of biologic, whichever occurred first; for malignancies, the exposure window was from study entry to death, cut-off date, or start of biologic. <h3>Results:</h3> As of May 31, 2022, 5874 patients with RA were included and exposed to GP2015 (n=196), a csDMARD (n=3526), or an anti-TNF (n=2152). Of the 196 patients receiving GP2015, 67 were biologic-naïve, 71 were ETN-experienced, and 57 were biologic-experienced; one patient had unknown biologic history. At baseline, the mean age was ~60 years and ~75% of patients were female. Mean time since diagnosis (years) was longer for the GP2015 cohort (13.8 [biologic-naïve: 7.9; ETN-experienced: 18.9; biologic-experienced: 14.3]) versus the csDMARD (9.7) and anti-TNF (8.7) cohorts. Mean Health Assessment Questionnaire scores (GP2015: 1.4 [biologic-naïve: 1.5; ETN-experienced: 1.7; biologic-experienced: 1.3]; csDMARD: 1.5; anti-TNF: 1.5) and Disease Activity Scores in 28 joints (GP2015: 5.0 [biologic-naïve: 5.7; ETN-experienced: 4.2; biologic-experienced: 4.1]; csDMARD: 5.1; anti-TNF: 5.9) were comparable between the cohorts at baseline. The adjusted HR (aHR) for the time to first serious infection was significantly lower for the GP2015 versus anti-TNF cohort (aHR [95% CI] 0.37 [0.17–0.80]; p&lt;0.05). Numerically lower rates of total first serious infections were observed for the GP2015 versus csDMARD cohort (Table 1); however, there was no statistically significant difference in aHR for time to first serious infection between these cohorts. Limitations of this analysis include the small sample size and different lines of therapy in the GP2015 cohort. <h3>Conclusion:</h3> GP2015 was associated with a significantly lower aHR for time to first serious infection versus other anti-TNFs and a lower, but nonsignificant, aHR versus csDMARDs. Due to the sample size, further investigations are required to confirm if GP2015 can be considered in patients in whom infection risk is a concern. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> These data were generated by a third party and provided to Sandoz for the primary purpose of pharmacovigilance and ongoing risk management. <h3>Disclosure of Interests:</h3> Christopher R. Holroyd AbbVie, Bristol Myers Squibb, Fresanius Kabi, Galapagos, Janssen, Eli Lilly, Novartis, and UCB, Susannah Earl AbbVie, Bristol Myers Squibb, Eli Lilly, and UCB, Charlotte Both Former employee of Sandoz, Cristofer Salvati Current employee of Sandoz.