Real-world Study on Secukinumab Effectiveness in Biologic-naïve Ankylosing Spondylitis (AS) Patients in Korea.

Inclusion Criteria: 1. Subjects diagnosed with ankylosing spondylitis (AS), as defined by the modified 1984 New York criteria 2. Subjects who have symptoms of active disease at screening and baseline, as evidenced by BASDAI score of ≥ 4 3. Subjects who have never used TNFi, JAKi, or IL-17i drugs before 4. Patients suitable for secukinumab treatment within the scope of labeling by the Ministry of Food and Drug Safety 5. Subjects who have a time of less than 5 years since AS diagnosis 6. Subjects who are above the age of 18 years and below 40years old 7. Subjects who give informed consent form to participate in the study Exclusion Criteria: 1. Subjects who are in a medical or psychological condition which may prevent them from participating in the study for the study period(28±4 weeks) 2. Subjects who have congenital/traumatic spinal deformities 3. Subjects currently enrolled in other clinical studies 4. Subjects who have any contraindications to secukinumab treatment