Objectives MAXIMISE (Managing AXIal Manifestations in psorIatic arthritis with SEcukinumab) trial was designed to evaluate the efficacy of secukinumab in the management of axial manifestations of psoriatic arthritis (PsA). Methods This phase 3b, double-blind, placebocontrolled, multi-centre 52-week trial included patients (≥18 years) diagnosed with PsA and classified by ClASsification criteria for Psoriatic Arthritis (CASPAR) criteria, with spinal pain Visual Analogue Score ≥40/100 and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score ≥4 despite use of at least two nonsteroidal anti-inflammatory drugs (NSAIDs). Patients were randomised (1:1:1) to secukinumab 300 mg, secukinumab 150 mg or placebo weekly for 4 weeks and every 4 weeks thereafter. At week 12, placebo patients were re-randomised to secukinumab 300/150 mg. Primary endpoint was ASAS20 (Assessment of SpondyloArthritis international Society) response with secukinumab 300 mg at week 12. Results Patients were randomly assigned; 167 to secukinumab 300 mg, 165 to secukinumab 150 mg and 166 to placebo. Secukinumab 300 mg and 150 mg significantly improved ASAS20 response versus placebo at week 12 (63% and 66% vs 31% placebo). The OR (95% CI) comparing secukinumab 300 mg and 150 mg versus placebo, using a logistic regression model after multiple imputation, was 3.8 (2.4 and 6.1) and 4.4 (2.7 and 7.0; p<0.0001). Conclusions Secukinumab 300 mg and 150 mg provided significant improvement in signs and symptoms of axial disease compared with placebo in patients with PsA and axial manifestations with inadequate response to NSAIDs. Trial registration number NCT02721966. INTRODUCTION Spondyloarthritis (SpA) refers to a group of interrelated inflammatory musculoskeletal disorders that include either peripheral or axial SpA (axSpA). Psoriatic arthritis (PsA), the main type of peripheral involvement of SpA, is a heterogeneous, chronic, progressive, inflammatory condition, associated with enthesitis, dactylitis, skin and nail psoriasis that can affect peripheral joints but also the axial skeleton, with diverse patterns of involvement that can mimic different inflammatory arthritides. 1 2 AxSpA is an inflammatory condition that can occur with (ankylosing spondylitis (AS) or radiographic axSpA) or without (non-radiographic axSpA) radiographic sacroiliitis. Although PsA and AS have a number of clinical features in common, AS accompanied with psoriasis and PsA with predominant axial involvement (axial PsA) are considered two separate disease entities with overlapping features. 3 4 Axial PsA is not clearly defined, universally accepted criteria for axial PsA are currently Key messages What is already known about this subject? ► Secukinumab, a fully human monoclonal antibody that directly inhibits interleukin (IL)-17A, has demonstrated significant and sustained efficacy across distinct clinical domains in active psoriatic arthritis (PsA). However, the efficacy of secukinumab or any other biological disease modifying antirheumatic drugs (bDMARDs) treatment specifically on axial manifestations in patients with PsA has never been investigated in a randomised controlled trial (RCT) setting. What does this study add? ► MAXIMISE (Managing AXIal Manifestations in psorIatic arthritis with SEcukinumab) is the first RCT to evaluate the efficacy of a bDMARD specifically in the management of the axial manifestations of PsA. Secukinumab 300 mg and 150 mg demonstrated significant improvements across the primary, key secondary and secondary clinical and imaging endpoints at week 12, which were sustained through week 52. How might this impact on clinical practice or future developments? ► The study provides evidence for the efficacy of IL-17A inhibition with secukinumab for the treatment of axial disease in patients with PsA. The results provide valuable data that will help inform treatment decision-making and deepen the clinical understanding of axial PsA, one of the disease manifestations lacking universally acceptable definition criteria.