Efficacy and Safety of SCT650C in Participants With Axial Spondyloarthritis

Percentage of Participants with Axial Spondyloarthritis Reporting Adverse Events (AEs), Serious Adverse Events (SAEs), and Treatment Emergent Adverse Events (TEAEs)

An adverse event (AE) is any untoward medical occurrence in a patient or clinical investigation participant administered a pharmaceutical product that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. A serious adverse event (SAE) is any untoward medical occurrence that at any dose: Results in death Is life-threatening Requires in patient hospitalisation or prolongation of existing hospitalisation Is a congenital anomaly or birth defect Is an infection that requires treatment parenteral antibiotics Other important medical events which based on medical or scientific judgement may jeopardise the patients, or may require medical or surgical intervention to prevent any of the above.

Percentage of Participants Achieving an Assessment of Spondyloarthritis International Society 40 (ASAS40) Response

The ASAS40 response was defined as relative improvements of at least 40% and absolute improvement of at least 2 units on a 0 to 10 Numeric Rating Scale (NRS), where 0 is "not active" and 10 is "very active" in at least 3 of the 4 domains: Patient's Global Assessment of Disease Activity (PGADA), Pain assessment (total spinal pain NRS score), Function (Bath Ankylosing Spondylitis Functional Index (BASFI)), Inflammation (mean of Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) questions 5 and 6 concerning morning stiffness intensity and duration) and no worsening at all in the remaining domain. Note: Participants with missing data or who discontinue study treatment prior to Week 12 were counted as non-responders.

Percentage of Participants With Axial Spondyloarthritis International Society 20% Response Criteria (ASAS20) at Week 16

The ASAS20 response was defined as an improvement of at least 20% and absolute improvement of at least 1 unit on a 0 to 10 NRS, where 0 is "not active" and 10 is "very active" in at least 3 of the 4 domains: PGADA, Pain assessment (total spinal pain NRS scores), Function (BASFI), Inflammation (mean of BASDAI questions 5 and 6 concerning morning stiffness intensity and duration) and absence of deterioration in the potential remaining domain \[deterioration was defined as a relative worsening of at least 20% and an absolute worsening of at least 1 unit\]. Note: Participants with missing data or who discontinue study treatment prior to Week 12 were counted as non-responders.

Change From Baseline in Ankylosing Spondylitis Disease Activity Score - C-Reactive Protein (ASDAS [CRP]) at Week 16

The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI question 2 result) 0.058 x Duration of morning stiffness (BASDAI question 6 result) 0.110 x PGADA 0.073 x Peripheral pain/swelling (BASDAI question 3 result) 0.579 x (natural logarithm of the (hs-CRP \[mg/L\] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue are all assessed on a numerical scale (0 to 10 units). The change from Baseline is calculated, a negative value indicating improvement and a positive value worsening. There is a minimum score of 0.636 for the total ASDAS score, but no defined upper score since CRP does not have a set upper limit. If one component for the ASDAS-CRP was missing at a given visit, that component was imputed by carrying the last observation forward, and the ASDAS-CRP was calculated accordingly. If the hs-CRP value was below 2 mg/L, then it was imputed as the constant value of 2 mg/L.

Change From Baseline to Week 16 in the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI)

The BASDAI is a validated self-reported instrument, which consists of six 10-unit horizontal Numeric Rating Scales (NRS) to measure severity of fatigue, spinal and peripheral joint pain and swelling, enthesitis, and morning stiffness (both severity and duration, respectively) over the last week. The final BASDAI score ranges from 0 to 10, with lower scores indicating lower disease activity. The change from Baseline is calculated, a negative value indicating improvement and a positive value worsening. Note: Missing data was imputed using multiple imputation based on the Markov-Chain Monte Carlo method for the intermittent missing data, followed by monotone regression for the monotone missing data assuming missing at random.

Change From Baseline to Week 16 in the Bath Ankylosing Spondylitis Functional Index (BASFI)

The BASFI is a validated disease-specific instrument for assessing physical function. The BASFI comprises 10 items relating to the past week. The BASFI is the mean of the 10 scores such that the total score ranges from 0 (Easy) to 10 (Impossible), with lower scores indicating better physical function. The change from Baseline is calculated, a negative value indicating improvement and a positive value worsening. Note: Missing data was imputed using multiple imputation based on the Markov-Chain Monte Carlo method for the intermittent missing data, followed by monotone regression for the monotone missing data assuming missing at random.