Lower injection-site reactions and long-term safety, immunogenicity, and efficacy of etanercept biosimilar YLB113: Results from a post-hoc analysis of a double-blind, randomized, phase III comparative study and its open-label extension in patients with rheumatoid arthritis.

aimYLB113 biosimilar was evaluated in an open-label extension single-arm study to assess long-term safety, efficacy, and immunogenicity in patients with rheumatoid arthritis (RA). We also report post-hoc results on the incidence of injection-site reactions (ISRs) and injection-site erythema (ISE) from a phase III study.

methodParticipants from the phase III, double-blind, randomized, 96 week equivalence study who completed the final visit received 50 mg YLB113 subcutaneously every 2 weeks. Key safety end points were assessed through adverse events (AEs), ISRs, ISE, and anti-drug antibody (ADA) incidence. The efficacy end point was change from baseline in Disease Activity Score 28-joint count (DAS28) over time.

resultsOf 201 participants, 184 (91.5%) completed the study. Treatment-emergent AEs were experienced by 93.5% and severe AEs by 10.0% of participants. The discontinuation rate due to AEs was 2.0%. Overall, 20.0% of participants reported an incidence of ISRs throughout the open-label extension study. Two participants developed ADAs, and none developed neutralizing ADAs at any time after study drug administration. The overall DAS28 (mean ± SD) change was 2.22 ± 0.95 at the study transition, 2.10 ± 0.91 at week 72, and 2.06 ± 0.89 at the end of the study. In the post-hoc analysis, YLB113 showed a statistically significant lower incidence of ISRs (10 [3.8%], P < 0.0001) and ISE (5 [1.9%], P < 0.0001) compared with the reference product Enbrel®.

conclusionYLB113 demonstrated long-term safety and sustained efficacy for up to 96 weeks. Patients on YLB113 experienced significantly lower ISRs and ISE in a post-hoc analysis of the phase III study when compared with reference product.