The BASDAI assesses disease activity by asking the participant to answer 6 questions (each on an 11 point numeric rating scale [NRS]) pertaining to symptoms experienced for the past week. For Questions 1 to 5 (level of fatigue/tiredness, level of AS neck, back or hip pain, level of pain/swelling in joints, other than neck, back or hips, level of discomfort from any areas tender to touch or pressure, and level of morning stiffness), the response is from 0 (none) to 10 (very severe); for Question 6 (duration of morning stiffness), the response is from 0 (0 hours) to 10 (≥ 2 hours). The overall BASDAI score ranges from 0 to 10. Lower scores indicate less disease activity.

A BASDAI 50 response is defined as improvement of 50% or more from Baseline in BASDAI score.

ASDAS is a composite index to assess disease activity in Ankylosing Spondylitis. ASDAS combines the following 5 disease activity variables using a weighted formula:

1. Patient's assessment of total back pain (BASDAI Question 2; NRS score 0 [none] - 10 [very severe])
2. Patient global assessment of disease activity (NRS score 0 [no activity] - 10 [severe activity])
3. Peripheral pain/swelling (BASDAI Question 3; NRS score 0 [none] - 10 [very severe])
4. Duration of morning stiffness (BASDAI Question 6; NRS score 0 [0 hours] - 10 [2 or more hours])
5. High-sensitivity C-reactive protein (hs-CRP) in mg/L. The overall score ranges from 0 with no defined upper score; published ranges for disease activity states as defined by the ASDAS include Inactive disease (ASDAS < 1.3) and very high disease (ASDAS > 3.5). A negative change from Baseline score indicates improvement in disease activity.

ASDAS is a composite index to assess disease activity in Ankylosing Spondylitis. ASDAS combines the following 5 disease activity variables using a weighted formula:

1. Patient's assessment of total back pain (BASDAI Question 2; NRS score 0 [none] - 10 [very severe])
2. Patient global assessment of disease activity (NRS score 0 [no activity] - 10 [severe activity])
3. Peripheral pain/swelling (BASDAI Question 3; NRS score 0 [none] - 10 [very severe])
4. Duration of morning stiffness (BASDAI Question 6; NRS score 0 [0 hours] - 10 [2 or more hours])
5. High-sensitivity C-reactive protein (hs-CRP) in mg/L. The overall score ranges from 0 with no defined upper score. ASDAS Inactive Disease is defined as an ASDAS score < 1.3.

Participants assessed their total back pain during the last week on a 0 to 10 numerical rating scale (NRS), where 0 represents no pain and 10 represents most severe pain.

Participants assessed the amount of back pain at night over the last week on a 0 to 10 NRS, where 0 represents no pain and 10 represents most severe pain.

ASDAS is a composite index to assess disease activity in Ankylosing Spondylitis. ASDAS combines the following 5 disease activity variables using a weighted formula:

1. Patient's assessment of total back pain (BASDAI Question 2; NRS score 0 [none] - 10 [very severe])
2. Patient global assessment of disease activity (NRS score 0 [no activity] - 10 [severe activity])
3. Peripheral pain/swelling (BASDAI Question 3; NRS score 0 [none] - 10 [very severe])
4. Duration of morning stiffness (BASDAI Question 6; NRS score 0 [0 hours] - 10 [2 or more hours])
5. High-sensitivity C-reactive protein (hs-CRP) in mg/L. The overall score ranges from 0 with no defined upper score. ASDAS Low Disease Activity is defined as an ASDAS score < 2.1.

The Bath Ankylosing Spondylitis Functional Index is a validated index to determine the degree of functional limitation in patients with AS. BASFI consists of 10 questions assessing participants' ability to perform activities such as putting on socks, bending, reaching, getting up from the floor or an armless chair, standing, climbing and other physical activities. Each item is scored on a NRS ranging from 0 (easy to perform an activity) to 10 (impossible to perform an activity). The overall score is the mean of the 10 items and ranges from 0 to 10 with higher scores indicating more functional limitations. A negative change from Baseline in BASFI indicates improvement.

The ASQoL consists of 18 items related to quality of life, including the impact of pain on sleep, mood, motivation, ability to cope, activities of daily living, independence, relationships, and social life. Each item is answered as yes (scored as 1) or no (scored as 0).

Scores are summed to obtain the overall score which ranges from 0 to 18, where higher scores indicate a worse quality of life. A negative change from Baseline in ASQoL indicates improvement in quality of life.

The BASMI is a composite score based on 5 direct measurements of spinal mobility:

1. cervical rotation (measured in degrees),
2. tragus to wall distance (in centimeters [cm])
3. lumbar side flexion (in cm),
4. lumbar flexion (modified Schober's) (in cm) and
5. intermalleolar distance (in cm). Each measurement is converted to a linear score between 0 and 10. The total BASMI score is the average of the 5 scores and ranges from 0 to 10; the higher the BASMI score the more severe the patient's limitation of movement due to their ankylosing spondylitis. A negative change from Baseline indicates improvement.

The MASES evaluation was conducted to assess the presence or absence of enthesitis (inflammation of the entheses, or sites where tendons or ligaments insert into the bone) at 13 different sites (first costochondral joint left/right, seventh costochondral joint left/right, posterior superior iliac spine left/right, anterior superior iliac spine left/right, iliac crest left/right, fifth lumbar spinous process, and proximal insertion of Achilles tendon left/right. Each site was scored for presence (1) or absence (0) of enthesitis. The MASES is the sum of the 13 site scores, and ranges from 0 to 13, with higher scores indicating more inflammation of the entheses. A negative change from Baseline indicates improvement.