This was a randomized, double-blind, placebo-controlled study. Approximately 134 participants were planned to be randomized in a 1:1 ratio to receive secukinumab 150 mg subcutaneously (s.c.) or placebo.
The double-blind treatment period lasted for 16 weeks. At the end of this period, all participants, including those who initially received placebo, switched to open-label treatment with secukinumab 150 mg s.c.
The first dose of open-label treatment was administered at the Week 16 visit, after completing all necessary assessments for that visit. However, the participants and investigators remained blinded to the original treatment assignment. At Week 24, participants who did not respond to the treatment (defined as not achieving Ankylosing SpondyloArthritis International Society 20 [ASAS20] response) were given a higher dose of secukinumab (300 mg s.c.), while responders continued with the 150 mg s.c. dose. The study treatment continued until Week 48. Four weeks after the last study treatment administration, an end-of-treatment visit was conducted at Week 52.
Additionally, a post-treatment safety follow-up visit was performed 12 weeks after the last study treatment administration for all participants, whether they completed the entire study as planned or exited early.