1430: Time to First Remission and Prevalence of Sustained Remission After Etanercept Biosimilar (ETA-B) or Originator (ETA-O) Initiation in Rheumatoid Arthritis

Cristiano Moura¹, Luck Lukusa¹, Laura Yan¹, Walter P Maksymowych², Denis Choquette³, Gilles Boire⁴ and Sasha Bernatsky¹, ¹Research Institute of the McGill University Health Centre, Montréal, QC, Canada, ²Department of Medicine, University of Alberta, Edmonton, AB, Canada, ³Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada, ⁴Universite de Sherbrooke, Sherbrooke, QC, Canada

Background/Purpose: The first biosimilar etanercept (ETA-B) was approved in Canada in 2016, but real-world data comparing the effectiveness of ETA-B versus its equivalent originator (ETA-O) remain scarce. We compared time to remission and the prevalence of sustained remission in the first 12 of follow-up in rheumatoid arthritis (RA) cohorts.

Methods: We studied etanercept-naïve RA patients starting ETA-B or ETA-O between January 2015 and May 2022 from three prospective cohorts in Canada: the Rheumatoid Arthritis Pharmacovigilance Program and Outcomes Research in Therapeutics (RAPPORT), the Early Undifferentiated Polyarthritis (EUPA) cohort, and the RHUMADATA® registry. We restricted the analyses to patients with at least one follow-up visit after treatment initiation and with enough data to calculate remission. Remission was defined as Disease Activity Score 28 (DAS28) -CRP or -ESR ≤2.6, Simplified Disease Activity Index (SDAI) ≤ 3.3, or Clinical Disease Activity Index (CDAI) ≤ 2.8. We used Cox regression analysis to compare ETA-B versus ETA-O regarding time to first remission during follow-up (among patients without remission at baseline) and logistic regression to assess the prevalence of sustained remission (remission in two consecutive visits) in the first 12 months of follow-up. Models were adjusted for sex, age, body mass index (BMI), disease duration, and smoking status at cohort entry. Models were also adjusted for high/moderate disease activity, corticosteroid use, methotrexate (MTX), or hydroxychloroquine (HCQ), all at etanercept initiation.

Results: We studied 150 RA patients initiating etanercept (65% on the biosimilar) between 2015-2022. Sex distribution was similar among ETA-B and ETA-O, but the biosimilar group has a longer disease duration and moderate/higher disease activity at baseline (Table 1). Among 125 patients without remission at baseline, the median time to first remission was 8.7 months with ETA-B versus 14.5 with ETA-O. In the multivariate analysis (Table 2), we were unable to detect a clear difference in achieving first remission when comparing ETA-B to ETA-O (hazard ratio, HR = 1.43, 95% confidence interval, CI 0.65-3.13). BMI >=30 was negatively associated with the outcome. Sustained remission in the first 12 months of follow-up was observed in 16.3% of ETA-B initiators versus 17.3% with ETA-O. After multivariate analysis (Table 3), there was no significant difference in the outcome between ETA-B and ETA-O (OR 1.16; 95%CI 0.31-4.74). The use of HCQ had a positive association with the outcome.

Conclusion: In this pooled analysis of three Canadian RA cohorts, we were unable to detect clear differences in achievement or sustained remission when comparing ETA-B and ETA-O.
Table 1 – RA patients initiating etanercept originator (ETA-O) and biosimilar (ETA-B)

Table 2 – Cox proportional hazard model results for time to remission

Table 3 – Logistic regression model results for prevalence of sustained remission in 12 months
Disclosures: C. Moura, None; L. Lukusa, None; L. Yan, None; W. Maksymowych, AbbVie, Boehringer-Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, UCB, CARE Arthritis Limited; D. Choquette, AbbVie/Abbott, Amgen, Eli Lilly, Fresenius Kabi, Novartis, Pfizer, Sandoz, Tavapharm; G. Boire, AbbVie/Abbott, Bristol-Myers Squibb(BMS), Janssen, Eli Lilly, Merck/MSD, Novartis, Orimed Pharma, Pfizer, Samsung Bioepis, Teva, Viatris, Amgen, Celgene; S. Bernatsky, None.