Adherence to therapy of ixekizumab and secukinumab in psoriatic arthritis patients using first- or second-line IL-17A inhibitor treatment: a Danish population-based cohort study.

Objectives: To assess the effectiveness and tolerability of first- and second-line interleukin (IL)-17A inhibitor treatment in PsA patients from 2014 to 2021 using data from the Danish Rheumatology Registry (DANBIO) by investigating adherence to therapy.

Method: PsA patients recorded in the DANBIO who received a first- or second-line IL-17A inhibitor treatment were included in this study. All patients included had previously received one or more TNF inhibitor treatment. Baseline characteristics were analysed in subgroups as first-line IL-17A inhibitor treatment and second-line IL-17A inhibitor treatment. Adherence to therapy of first- or second-line IL-17A inhibitor treatments was reported as Kaplan-Meier plots.

Results: A total of 534 patients were included in the study, with 534 first-line switchers (secukinumab: 510, ixekizumab: 24) and 102 second-line switchers (secukinumab: 35, ixekizumab: 67). Baseline characteristics showed a similar HAQ and visual analogue scale (VAS) for pain. VAS global, 28-joint DAS with CRP and the previous number of biologic DMARD treatments were similar, with a greater value for second-line switchers. First-line ixekizumab-treated patients present a younger age, greater percentage of females, a lower disease duration and a lower CRP value. Concomitant MTX use was greater for the first-line secukinumab-treated patients. First- and second-line switchers had a similar adherence to therapy. Second-line secukinumab and second-line ixekizumab switchers showed a similar adherence to treatment.

Conclusion: PsA patients receiving first- or second-line IL-17A inhibitors showed homogeneous baseline characteristics and similar adherence to therapy. Treatment failure of the first IL-17A inhibitor treatment should not preclude a second-line IL-17A inhibitor treatment.