adalimumab biosimilar 40 mg will be administered at Baseline followed by dosing every 2 weeks until Week 24

stable dose

If patients have inadequate response to bioagents, thalidomide 50 mg will be administered at 12 week followed by dosing everyday until Week 24.

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

Patient's assessment of total back pain (BASDAI Question 2; NRS score 0 [none] - 10 [very severe]) Patient global assessment of disease activity (NRS score 0 [no activity] - 10 [severe activity]) Peripheral pain/swelling (BASDAI Question 3; NRS score 0 [none] - 10 [very severe]) Duration of morning stiffness (BASDAI Question 6; NRS score 0 [0 hours] - 10 [2 or more hours]) 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.

ASAS 40 response was defined as improvement of ≥ 40% relative to Baseline and absolute improvement of ≥ 2 units (on a scale from 0 to 10) in ≥ 3 of the following 4 domains with no deterioration (defined as a net worsening of > 0 units) in the potential remaining domain:

Patient's global assessment of disease activity, measured on a numeric rating scale (NRS) from 0 (no activity) to 10 (severe activity); Pain, measured by the total back pain NRS from 0 (no pain) to 10 (most severe pain); Function, measured by the Bath Ankylosing Spondylitis Functional Index (BASFI) which consists of 10 items assessing participants' ability to perform activities on an NRS ranging from 0 (easy) to 10 (impossible); Inflammation, measured by the mean of the 2 morning stiffness-related Bath AS Disease Activity Index (BASDAI) NRS scores (items 5 [level of stiffness] and 6 [duration of stiffness]) each on a scale from 0 (none/0 hours) to 10 (very severe/2 hours or more duration).

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.

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

cervical rotation (measured in degrees), tragus to wall distance (in centimeters [cm]) lumbar side flexion (in cm), lumbar flexion (modified Schober's) (in cm) and 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 ASAS HI measures functioning and health across 17 aspects of health in patients with AS, including pain, emotional functions, sleep, sexual function, mobility, self care, and community life. Each of the 17 questions is answered by the participant as "I agree" (score = 1) or "I disagree" (score = 0). The responses to the 17 dichotomous items are summed up to give a total score ranging from 0 to 17, where a higher score indicates a worse health status. A negative change from Baseline indicates improvement.

Change from Baseline in ESR, ESR will be measured with blood samples.

Change from Baseline in C-reactive Protein (CRP), a component index of ASDAS will be measured with blood samples.

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.

modiifed stoke ankylosing spondylitis spine score ( range 0-72), a system for grading and evaluating cervical spine, lumbar spine, sacroiliac joint and hip joint by X-ray.

T cell subsets, including cytotoxic T (Tc) cells, helper T (Th) cells