FRI0128 A Phase III Randomised, Double-Blind Clinical Study Comparing SB4, An Etanercept Biosimilar, With Etanercept Reference Product (Enbrel®) in Patients with Moderate to Severe Rheumatoid Arthritis Despite Methotrexate Therapy (24-Week Results)

Background SB4 is a biologic agent developed as a biosimilar of the etanercept reference product (ETN). Etanercept is approved for treatment of rheumatoid arthritis (RA), juvenile idiopathic arthritis, psoriatic arthritis, axial spondyloarthritis, plaque psoriasis, and paediatric plaque psoriasis in the EU. Objectives To compare the efficacy, safety, and immunogenicity of SB4 with ETN in patients with moderate to severe RA despite methotrexate (MTX) treatment. Methods Patients with moderate to severe RA despite MTX treatment were randomly assigned to receive weekly dose of 50 mg SB4 or ETN administered subcutaneously for 52 weeks. The primary endpoint was the ACR20 response rate at Week 24. Other endpoints including safety and immunogenicity were also measured. Results A total of 596 patients were randomised to either SB4 (N=299) or ETN (N=297). Baseline demographic and disease characteristics were comparable between two treatment groups. The ACR20 response rate at Week 24 in the per-protocol set (PPS) was 78.1% (193/247) in SB4 and 80.3% (188/234) in ETN. The 95% confidence interval (CI) of the treatment difference adjusted by region and baseline C-reactive protein was –9.41% to 4.98%, which was within the pre-defined equivalence margin of [–15%, 15%]. The ACR20 response rate at Week 24 was shown to be equivalent in the full analysis set as well (95% CI: −5.24%, 9.07%) when non-responder analysis was applied. The estimated difference between the time-response curves of SB4 and ETN in the PPS was contained within the pre-defined equivalence margin (Figure). The ACR50 response rates at Week 24 in the PPS were 46.6% vs. 42.3% and the ACR70 response rates were 25.5% vs. 22.6% in SB4 and ETN, respectively. The safety profile of SB4 was generally comparable to that of ETN (Table). Conclusions SB4 was shown to be equivalent in terms of clinical efficacy when compared with ETN. SB4 was well tolerated with a comparable safety profile to ETN. Disclosure of Interest J. Vencovský Grant/research support from: Samsung Bioepis, Speakers bureau: UCB, Pfizer, AbbVie, MSD, A. Sylwestrzak Grant/research support from: Samsung Bioepis, P. Leszczynski Grant/research support from: Samsung Bioepis, Roche, MSD, Janssen, Novo Nordisk, UCB, Pfizer, Novartis, GSK, BHS, Consultant for: Samsung Bioepis, Roche, MSD, Paid instructor for: Novo Nordisk, Speakers bureau: MSD, UCB, Roche, Amgen, W. Porawska Grant/research support from: Samsung Bioepis, A. Baranauskaite Grant/research support from: Samsung Bioepis, V. Tseluyko Grant/research support from: Samsung Bioepis, V. Zhdan Grant/research support from: Samsung Bioepis, B. Stasiuk Grant/research support from: Samsung Bioepis, R. Milasiene Grant/research support from: Samsung Bioepis, A. A. Barrera Rodriguez Grant/research support from: Samsung Bioepis, S. Y. Cheong Employee of: Samsung Bioepis, J. Ghil Employee of: Samsung Bioepis, P. Emery Grant/research support from: AbbVie, Pfizer, Consultant for: AbbVie, BMS, Pfizer, UCB, MSD, Roche, Novartis, Takeda, Lilly, Samsung Bioepis