Multicenter Study Evaluating Certolizumab Pegol Compared to Placebo in Subjects With axSpA Without X-ray Evidence of AS

Inclusion Criteria:

- At least 18 years old at the start of Screening Visit

- A documented diagnosis of adult-onset axial SpondyloArthritis (axSpA) and meet the
Assessment of SpondyloArthritis International Society (ASAS) criteria for axSpA

- Subjects must have had back pain for at least 12 months before Screening

- No sacroiliitis defined by Modified New York (mNY) criteria on sacroiliac (SI) x-rays

- Active disease at Screening as defined by

- Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score >= 4

- Spinal pain >= 4 on a 0 to 10 Numerical Rating Scale (NRS)

- Inadequate response to, have a contraindication to, or have been intolerant to at
least 2 Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

Exclusion Criteria:

- Diagnosis of AS or any other Inflammatory Arthritis

- Prior treatment with any experimental biological agents for treatment of Axial
SpondyloArthritis (SpA)

- Exposure to more than 1 tumor necrosis factor (TNF)-antagonist or primary failure to
TNF antagonist therapy

- History of or current chronic or recurrent infections

- Subjects with known Tuberculosis (TB) infection, at high risk of acquiring TB
infection, or latent Tuberculosis (LTB)

- Recent live vaccination

- Concurrent malignancy or a history of malignancy

- Class III or IV congestive heart failure - New York Heart Association (NYHA)

- Demyelinating disease of the central nervous system

- Female subjects who are breastfeeding, pregnant or plan to become pregnant during the
study or within 3 months following the last dose of the investigational product

- Subjects with any other condition which, in the investigator's judgment, would make
the subject unsuitable for inclusion in the study