['ankylosing spondylitis']
['filgotinib', 'placebo oral tablet']

        Key Inclusion Criteria:

          -  Male or female subjects who are ≥18 years of age on the day of signing informed
             consent.

          -  Diagnosis of moderate to severe ankylosing spondylitis with documented evidence of
             fulfilling the Modified New York (NY) criteria

          -  Have active ankylosing spondylitis with a BASDAI ≥4 (numeric rating scale [NRS] 0-10)
             and spinal pain ≥4 (0-10 NRS) (based on BASDAI question 2, see protocol) at screening
             and baseline.

          -  Have had a documented inadequate response to NSAIDs including cyclooxygenase-2 (COX-2)
             inhibitors.

          -  If using cDMARD therapy, stable dose for at lead 4 weeks prior to Baseline.

          -  If using non-drug therapies (including physical therapies), these should be kept
             stable during screening.

          -  Male and female subjects of childbearing potential who engage in heterosexual
             intercourse must agree to use highly effective methods of contraception as described
             in the protocol.

        Key Exclusion Criteria:

          -  Use of JAK inhibitors, investigational or approved, at any time, including filgotinib;

          -  Prior use of more than one TNF inhibitor, at any time.

          -  Use of oral steroids at a dose >10 mg/day of prednisone or prednisone equivalent or at
             a dose that hasn't been stable for at least 4 weeks prior to baseline;

          -  Any therapy by intra-articular injections (e.g. corticosteroid, hyaluronate) within 4
             weeks prior to screening;

          -  Use of more than 1 NSAID or COX-2 inhibitor.

          -  Contraindication to MRI.

          -  History of known or suspected complete ankylosis of the spine.

          -  Presence of very poor functional status or unable to perform self-care.

          -  Have undergone surgical treatment for ankylosing spondylitis within the last 12 weeks
             prior to screening.

          -  Administration of a live or attenuated vaccine within 12 weeks prior to baseline.
      