This study aimed to describe baseline characteristics and compare treatment effectiveness of secukinumab versus tumor necrosis factor inhibitors (TNFi) in patients with spondyloarthritis (SpA) using adalimumab as the main comparator.

An observational, prospective cohort study. Patients with SpA starting secukinumab or a TNFi during 2015‐2018 were identified from five Nordic clinical rheumatology registries. Comorbidities and extra‐articular manifestations were captured from national registries and included in multivariable analyses. We assessed 1‐year treatment retention and 6‐months’ response‐rates, stratified by line of biological treatment. In total, 10,853 treatment courses were included. Extra‐articular manifestations varied across treatments, while other baseline characteristics were largely similar. Secukinumab had 1‐year retention comparable to adalimumab as 1st or 2nd, but poorer as 3rd+ line of therapy (secukinumab 56% vs. adalimumab 70%), adjusted HR 1.43. Across treatment lines, secukinumab had poorer estimates for 6‐months response rates than adalimumab, statistically significantly so only for 3rd+ line. Treatment outcomes varied across the five TNFi.

In conclusion, Secukinumab was mainly used in biologically experienced SpA patients. Secukinumab and adalimumab performed similarly in patients who had failed a first biological, although with increasing prior biological exposure, adalimumab was superior.