ASAS 20 response is a validated composite assessment, defined as an improvement of at least 20 percent (%) and 1 unit on a scale of 10 in three main domains and no worsening of at least 20% and 1 unit on a scale of 10 in the fourth domain within a defined time frame. Four main ASAS domains include: 1. Patient's global assessment of disease activity measured on a 100 mm VAS ranging from not severe to very severe 2. Patient's assessment of back pain, measured on a 100 mm VAS ranging from no pain to unbearable pain 3. Function represented by Bath Ankylosing Spondylitis Functional Index (BASFI) average of 10 questions regarding ability to perform specific tasks as measured by a 0-10 VAS scale 4. Inflammation represented by average of duration and severity of morning stiffness for last 2 questions on BASDAI scale (0 - no problem, 10 - worst problem)

The analysis was performed in Full analysis set (FAS) population, defined as all participants who were randomized and received study treatment. Here, "Number of participants analysed" signifies participants evaluable for ASAS20 at Week 16.

ASAS 20 response is a validated composite assessment, defined as an improvement of at least 40% and 2 unit on a scale of 10 in three main domains and no worsening at all in the remaining domain within a defined time frame. Four main ASAS domains include:

1. Patient's global assessment of disease activity measured on a 100 mm VAS ranging from not severe to very severe
2. Patient's assessment of back pain, measured on a 100 mm VAS ranging from no pain to unbearable pain
3. Function represented by Bath Ankylosing Spondylitis Functional Index (BASFI) average of 10 questions regarding ability to perform specific tasks as measured by a 0-10 VAS scale
4. Inflammation represented by average of duration and severity of morning stiffness for last 2 questions on BASDAI scale (0 - no problem, 10 - worst problem).

The analysis was performed in FAS population. Here, "Number of participants analysed" signifies participants evaluable for ASAS 40 response at Week 16.

Blood levels of C-reactive protein (CRP) is an acute phase reactant, which are indicative of inflammation and of its severity, and can be used to monitor treatment response. A hsCRP test is implemented to assess the efficacy of secukinumab (with or without load) versus placebo in reducing ankylosing spondylitis elicited systemic inflammation over the time.

The analysis was performed in FAS population. Here, "Number of participants analysed" signifies participants evaluable for hsCRP at Week 16.

ASAS 5/6 response is a validated composite assessment, defined as an improvement of at least 20% in score in at least 5 of 6 clinical domains relevant to ankylosing spondylitis and no worsening in the remaining domain. ASAS domains includes:

1. Patient's global assessment of disease activity measured on a 100 mm VAS ranging from not severe to very severe
2. Patient's assessment of back pain, measured on a 100 mm VAS ranging from no pain to unbearable pain
3. Function represented by BASFI average of 10 questions regarding ability to perform specific tasks as measured by a 0-10 VAS scale
4. Inflammation represented by average of duration and severity of morning stiffness for last 2 questions on BASDAI scale (0 - no problem, 10 - worst problem)
5. Spinal mobility represented by the Bath Ankylosing Spondylitis Metrology Index (BASMI) lateral spinal flexion assessment
6. C-reactive protein (CRP, acute phase reactant).

The analysis was performed in FAS population. Here, "Number of participants analysed" signifies participants evaluable for ASAS 5/6 response at Week 16.

BASDAI is a validated assessment tool using 0 through 10 scales (0 indicating "no problem" and 10 indicating "worst problem" on continuous VAS), to answer 6 questions (clinical domains) pertaining to 5 major symptoms of ankylosing spondylitis. Computed composite scores of 4 or greater indicate suboptimal disease control. BASDAI questions includes:

1. Fatigue
2. Spinal pain
3. Joint pain / swelling
4. Areas of localized tenderness (called enthesitis, or inflammation of tendons and ligaments)
5. Morning stiffness duration
6. Morning stiffness severity. Each symptom has equal weighting, the mean of two scores related to morning stiffness was taken (questions 5 and 6). The resulting 0 to 10 score was added to the scores from questions 1-4. The resulting 0 to 50 score was divided by 5 to give a final 0-10 BASDAI score. BASDAI was a quick and simple index taking between 30 seconds and 2 minutes for completion.

The analysis was performed in FAS population. Here, "Number of participants analysed" signifies participants evaluable for BASDAI at Week 16.

SF-36 is a 36 item questionnaire which measures Quality of Life across eight subscales that were scored individually: physical functioning, role- physical, bodily pain, general health, vitality, social functioning, role-emotional, and mental health. Scores are weighted sums of the questions in each section. Scores range from 0-100. Lower scores = more disability, higher scores = less disability. The overall summary scores, SF-36 physical Component Summary (PCS) was used to assess improvement from baseline in the Health-Related Quality Of Life of subjects. The change in SF-36 scores were evaluated using MMRM.

The analysis was performed in FAS population.Here, "Number of participants analysed" signifies participants evaluable for PCS of the SF-36 at Week 16.

ASQoL is a self-administered 18 item questionnaire that assesses disease-specific quality of life (QoL), consisting of statements that are relevant to the physical and mental conditions for a subject with ankylosing spondylitis: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each statement is answered as a 'Yes' (scored as 1) or 'No' (scored as 0). All item scores are summed to give a total score. Total score ranges from 0 (good QoL) to 18 (poor QoL). The change in ASQoL scores was evaluated using a mixed effect repeated measures model (MMRM).

The analysis was performed in FAS population. Here, "Number of participants analysed" signifies participants evaluable for ASQoL at Week 16.

AEs were defined as any unfavorable and unintended diagnosis, symptom, sign (including an abnormal laboratory finding), syndrome or disease which either occurs during study, having been absent at baseline, or, if present at baseline, appears to worsen. SAEs were defined as any untoward medical occurrences that result in death, are life threatening, require (or prolong) hospitalization, cause persistent or significant disability/incapacity, result in congenital anomalies or birth defects, or are other conditions which in judgement of investigators represent significant hazards.

The analysis was performed on the safety population, defined as all participants who took at least one dose of study treatment during the treatment period.

ASAS 20 response is a validated composite assessment, defined as an improvement of at least 20% and 1 unit on a scale of 10 in three main domains and no worsening of at least 20% and 1 unit on a scale of 10 in the fourth domain within a defined time frame. Four main ASAS domains include:

1. Patient's global assessment of disease activity measured on a 100 mm VAS ranging from not severe to very severe
2. Patient's assessment of back pain, measured on a 100 mm VAS ranging from no pain to unbearable pain
3. Function represented by Bath Ankylosing Spondylitis Functional Index (BASFI) average of 10 questions regarding ability to perform specific tasks as measured by a 0-10 VAS scale
4. Inflammation represented by average of duration and severity of morning stiffness for last 2 questions on BASDAI scale (0 - no problem, 10 - worst problem).

The analysis was performed in FAS population. Here, "Number of participants analysed" signifies participants evaluable for ASAS 20 at Week 16.

ASAS 20 response is a validated composite assessment, defined as an improvement of at least 40% and 2 unit on a scale of 10 in three main domains and no worsening at all in the remaining domain within a defined time frame. Four main ASAS domains include:

1. Patient's global assessment of disease activity measured on a 100 mm VAS ranging from not severe to very severe
2. Patient's assessment of back pain, measured on a 100 mm VAS ranging from no pain to unbearable pain
3. Function represented by Bath Ankylosing Spondylitis Functional Index (BASFI) average of 10 questions regarding ability to perform specific tasks as measured by a 0-10 VAS scale
4. Inflammation represented by average of duration and severity of morning stiffness for last 2 questions on BASDAI scale (0 - no problem, 10 - worst problem).

The analysis was performed in FAS population. Here, "Number of participants analysed" signifies participants evaluable for ASAS 40 response at Week 16.