A Multicentre Study to Evaluate the Efficacy and Safety of ENIA11 in Patients With Ankylosing Spondylitis

This is a multi-center, double-blind, randomized, parallel-group, placebo-controlled study to evaluate the efficacy and safety of ENIA11 in patients with ankylosing spondylitis. The study period for each patient will be 27 weeks, during which the patient will undergo screening for up to 21 days, and followed by treatment of 24 weeks and follow up period of 2 weeks. Each patient will be required to make a total of 9 visits. After re-confirming the eligibility of patients at Visit 2, eligible patients will be randomly assigned to either treatment group or control group in a 2:1 ratio. In addition, patients in the treatment group will receive ENIA11 25 mg twice weekly by subcutaneous injection while patients in the control group will receive placebo solution twice weekly by subcutaneous injection from Day 0 to week 12 and then switch to active drug from week 12 to week 24 and follow up period of 2 weeks. The efficacy analysis, including ASAS response measures, ASAS5/6, ASDAS, BASDAS, BASFI, BASMI and individual measures of disease activity, such as numbers of swollen and tender joints, ESR and CRP, will be evaluated at each visit from Visit 2 (baseline) to Visit 9. Safety will be evaluated according to the frequency of adverse events, vital signs, physical examination, laboratory abnormalities, and ENIA11 antibody formation.