Comparative clinical efficacy and safety of the proposed biosimilar ABP 710 with infliximab reference product in patients with rheumatoid arthritis.

Background: ABP 710 is being developed as a biosimilar to infliximab reference product (RP). Analytical similarity and pharmacokinetic equivalence between the two have been previously demonstrated. Here we report results from a comparative clinical study that evaluated the efficacy and safety of ABP 710 relative to the RP in patients with rheumatoid arthritis (RA).

Methods: In this multicenter, randomized, double-blind, 50-week equivalence study, patients with moderate to severe active RA despite methotrexate received 3-mg/kg infusions of ABP 710 or RP at predetermined intervals based on initial randomization and then with re-randomization at week 22. The primary endpoint was response difference (RD) of ACR20 at week 22, with clinical equivalence evaluated based on 90% CI of - 15%, 15%. Secondary endpoints included Disease Activity Score 28-joint count C-reactive protein (DAS28-CRP), ACR20, ACR50, and ACR70 across time, as well as safety and immunogenicity assessments.

Results: A total of 558 patients were randomized for the initial treatment (ABP 710 n = 279; RP n = 279). The estimated RD of ACR20 at week 22 was 9.37% with 90% CI (2.67%, 15.96%). The lower bound was within the pre-specified criteria, thus confirming non-inferiority; the upper bound exceeded the pre-specified criteria by 0.96% such that superiority could not be ruled out statistically. In a post hoc analysis with adjustment for random imbalance in baseline factors, the CI of RD was narrowed (0.75%, 13.62%). Changes from baseline in DAS28-CRP as well as ACR20, ACR50, and ACR70 response rates across time and hybrid ACR evaluations were similar for the initial and initial/re-randomized treatment groups. Adverse events and incidence of anti-drug antibodies were similar between treatment groups.

Conclusions: These efficacy and safety results support similarity with no clinically meaningful differences between ABP 710 and infliximab RP. Although we were unable to statistically confirm non-superiority, post hoc analysis was supportive of non-superiority. DAS28-CRP, ACR20, ACR50, ACR70, and hybrid ACR evaluations over the entire study were consistently comparable as were safety and immunogenicity.

Trial Registration: ClinicalTrials.gov. Identifier: NCT02937701. Registered August 30, 2016.