Efficacy and safety of ixekizumab in patients with active psoriatic arthritis with and without concomitant conventional disease-modifying antirheumatic drugs: SPIRIT-P1 and SPIRIT-P2 3-year results.

INTRODUCTION/OBJECTIVES: To evaluate the three-year efficacy and safety of ixekizumab with and without concomitant conventional synthetic disease-modifying antirheumatic drug (csDMARD) use in patients with active psoriatic arthritis (PsA).

METHOD

Patients with PsA who were biologic-naïve (SPIRIT-P1, NCT01695239) or had prior inadequate response to tumor necrosis factor inhibitors (SPIRIT-P2, NCT02349295) were randomized to receive 80-mg ixekizumab every four weeks after receiving 160-mg ixekizumab at baseline. Efficacy, safety, and immunogenicity were evaluated in this post-hoc analysis in three subgroups: (1) ixekizumab monotherapy, (2) ixekizumab and methotrexate (MTX), (3) ixekizumab and any csDMARD (including MTX). Missing data were imputed using multiple imputation for continuous variables and modified non-responder imputation for categorical variables.

RESULTS

Efficacy was similar across the three subgroups with 59.1%, 67.0%, and 66.1% of ixekizumab-treated patients achieving 20% improvement in the American College of Rheumatology scale score at week 156. Radiographic progression of structural joint damage (SPIRIT-P1 only) was similarly inhibited across the three subgroups with several outliers. No new safety signals were reported, and 91.0%, 84.1%, and 83.2% in the three subgroups reported ≥ 1 treatment-emergent adverse event. At week 156, 15.9%, 13.1%, and 11.0% in the three subgroups had antidrug antibodies; most had low titer status.

CONCLUSIONS

Ixekizumab showed sustained efficacy in treating patients with PsA for up to three years in monotherapy or in combination with MTX or any csDMARD. The three subgroups had similar safety and immunogenicity profiles, which supports that the use of concomitant MTX or csDMARDs does not seem to impact the benefit/risk profile of ixekizumab. Key Points • Ixekizumab treatment led to improved clinical responses over time when used as monotherapy or in combination with concomitant MTX or any concomitant csDMARD (including MTX) in patients with active PsA. • Ixekizumab monotherapy has similar radiographic efficacy as ixekizumab with MTX or ixekizumab with other csDMARDs (including MTX); similar inhibition of radiographic progression was observed between the subgroups of patients receiving ixekizumab monotherapy or ixekizumab with MTX or other csDMARDs. • The long-term safety profile of ixekizumab used as monotherapy or in combination with MTX or any other csDMARDs is consistent with what has been previously reported. The addition of MTX or any csDMARD to ixekizumab treatment did not negatively impact the favorable long-term safety profile of ixekizumab.