A Study to Evaluate the Long-term Safety, Tolerability and Efficacy of Bimekizumab in Subjects With Active Axial Spondyloarthritis Including Ankylosing Spondylitis and Nonradiographic Axial Spondyloarthritis

An adverse event (AE) is any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product, which does not necessarily have a causal relationship with this treatment. An AE could 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 with 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

Treatment-emergent adverse events (TEAEs) are any untoward medical incidence in a subject during administered study treatment, whether or not these events are related to study treatment.

ASAS40 will be calculated relative to Baseline of AS0010 (NCT03928704) or AS0011 (NCT03928743). The Assessment of SpondyloArthritis International Society (ASAS) criteria for 40% improvement are 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) in at least 3 of the 4 domains and no worsening at all in the remaining domain.

The domains are:

• Patient's Global Assessment of Disease Activity (PGADA)
• Pain assessment (the total spinal pain, NRS score)
• Function (represented by Bath Ankylosing Spondylitis Functional Index (BASFI))-
• Inflammation (the mean of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) question 5 and 6 concerning morning stiffness intensity and duration)

ASAS40 will be calculated relative to Baseline of AS0010 (NCT03928704) or AS0011 (NCT03928743). The Assessment of SpondyloArthritis International Society (ASAS) criteria for 40% improvement are 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) in at least 3 of the 4 domains and no worsening at all in the remaining domain.

The domains are:

• Patient's Global Assessment of Disease Activity (PGADA)
• Pain assessment (the total spinal pain, NRS score)
• Function (represented by Bath Ankylosing Spondylitis Functional Index (BASFI))
• Inflammation (the mean of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI))

ASAS40 will be calculated relative to Baseline of AS0010 (NCT03928704) or AS0011 (NCT03928743). The Assessment of SpondyloArthritis International Society (ASAS) criteria for 40% improvement are 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) in at least 3 of the 4 domains and no worsening at all in the remaining domain.

The domains are:

• Patient's Global Assessment of Disease Activity (PGADA)
• Pain assessment (the total spinal pain, NRS score)
• Function (represented by Bath Ankylosing Spondylitis Functional Index (BASFI))
• Inflammation (the mean of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI))

ASAS20 will be calculated relative to Baseline of AS0010 (NCT03928704) or AS0011 (NCT03928743). The Assessment of SpondyloArthritis International Society (ASAS) criteria for 20% improvement are defined as relative improvements of at least 20%, and absolute improvement of at least 1 unit on a 0 to 10 Numeric Rating Scale (NRS) in at least 3 of the 4 following domains and absence of deterioration in the potential remaining domain.

The domains are:

• Patient's Global Assessment of Disease Activity (PGADA)
• Pain assessment (the total spinal pain, NRS score)
• Function (represented by Bath Ankylosing Spondylitis Functional Index (BASFI))
• Inflammation (the mean of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI))

ASAS20 will be calculated relative to Baseline of AS0010 (NCT03928704) or AS0011 (NCT03928743). The Assessment of SpondyloArthritis International Society (ASAS) criteria for 20% improvement are defined as relative improvements of at least 20%, and absolute improvement of at least 1 unit on a 0 to 10 Numeric Rating Scale (NRS) in at least 3 of the 4 following domains and absence of deterioration in the potential remaining domain.

The domains are:

• Patient's Global Assessment of Disease Activity (PGADA)
• Pain assessment (the total spinal pain, NRS score)
• Function (represented by Bath Ankylosing Spondylitis Functional Index (BASFI))
• Inflammation (the mean of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI))

ASAS20 will be calculated relative to Baseline of AS0010 (NCT03928704) or AS0011 (NCT03928743). The Assessment of SpondyloArthritis International Society (ASAS) criteria for 20% improvement are defined as relative improvements of at least 20%, and absolute improvement of at least 1 unit on a 0 to 10 Numeric Rating Scale (NRS) in at least 3 of the 4 following domains and absence of deterioration in the potential remaining domain.

The domains are:

• Patient's Global Assessment of Disease Activity (PGADA)
• Pain assessment (the total spinal pain, NRS score)
• Function (represented by Bath Ankylosing Spondylitis Functional Index (BASFI))
• Inflammation (the mean of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI))

The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is a validated self-reported instrument, which consists of six 10-unit horizontal Numeric Rating Scales (NRS) to measure the disease activity of ankylosing spondylitis (AS) from the subject's perspective. It measures the severity of fatigue, spinal and peripheral joint pain and swelling, enthesitis, and morning stiffness (both severity and duration) over the last week. The final BASDAI score ranges from 0 to 10, with lower scores indicating lower disease activity.

The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is a validated self-reported instrument, which consists of six 10-unit horizontal Numeric Rating Scales (NRS) to measure the disease activity of ankylosing spondylitis (AS) from the subject's perspective. It measures the severity of fatigue, spinal and peripheral joint pain and swelling, enthesitis, and morning stiffness (both severity and duration) over the last week. The final BASDAI score ranges from 0 to 10, with lower scores indicating lower disease activity.

The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is a validated self-reported instrument, which consists of six 10-unit horizontal Numeric Rating Scales (NRS) to measure the disease activity of ankylosing spondylitis (AS) from the subject's perspective. It measures the severity of fatigue, spinal and peripheral joint pain and swelling, enthesitis, and morning stiffness (both severity and duration) over the last week. The final BASDAI score ranges from 0 to 10, with lower scores indicating lower disease activity.

The Assessment of SpondyloArthritis International Society partial remission (ASAS-PR) is defined as a score of <=2 units on a 0 to 10 unit scale in all 4 domains listed for ASAS40 domains.

The Assessment of SpondyloArthritis International Society partial remission (ASAS-PR) is defined as a score of <=2 units on a 0 to 10 unit scale in all 4 domains listed for ASAS domains.

The Assessment of SpondyloArthritis International Society partial remission (ASAS-PR) is defined as a score of <=2 units on a 0 to 10 unit scale in all 4 domains listed for ASAS domains.

The ASDAS-C-Reactive Protein (ASDAS-CRP) consists of a number of assessments which are scored by the study participant and physician and multiplied by a proven formula as shown below:

0.121 x Total back pain (represented by the BASDAI Question 2 result) 0.058 x Duration of morning stiffness (represented by the BASDAI Question 6 result) 0.110 x PGADA 0.073 x Peripheral pain/swelling (represented by the 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 sum of these weighted components gives the ASDAS-CRP.

The ASDAS-C-Reactive Protein (ASDAS-CRP) consists of a number of assessments which are scored by the study participant and physician and multiplied by a proven formula as shown below:

0.121 x Total back pain (represented by the BASDAI Question 2 result) 0.058 x Duration of morning stiffness (represented by the BASDAI Question 6 result) 0.110 x PGADA 0.073 x Peripheral pain/swelling (represented by the 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 sum of these weighted components gives the ASDAS-CRP.

The ASDAS-C-Reactive Protein (ASDAS-CRP) consists of a number of assessments which are scored by the study participant and physician and multiplied by a proven formula as shown below:

0.121 x Total back pain (represented by the BASDAI Question 2 result) 0.058 x Duration of morning stiffness (represented by the BASDAI Question 6 result) 0.110 x PGADA 0.073 x Peripheral pain/swelling (represented by the 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 sum of these weighted components gives the ASDAS-CRP.+ 1)

The Assessment of SpondyloArthritis International Society (ASAS) 5/6 response is defined as achieving at least 20% improvement in 5 of 6 domains, including the 4 domains defined for ASAS40 domains as well as spinal mobility (lateral spinal flexion) and high sensitivity C-reactive Protein (hs-CRP).

The Assessment of SpondyloArthritis International Society (ASAS) 5/6 response is defined as achieving at least 20% improvement in 5 of 6 domains, including the 4 domains defined for ASAS domains as well as spinal mobility (lateral spinal flexion) and high sensitivity C-reactive Protein (hs-CRP).

The Assessment of SpondyloArthritis International Society (ASAS) 5/6 response is defined as achieving at least 20% improvement in 5 of 6 domains, including the 4 domains defined for ASAS domains as well as spinal mobility (lateral spinal flexion) and high sensitivity C-reactive Protein (hs-CRP).

The Bath Ankylosing Spondylitis Functional Index (BASFI) assesses physical function in comprising 10 items relating to activities during the past week. Each item ranges from 0 ('Easy') to 10 ('Impossible'). The BASFI is the mean of the 10 scores such that the total score ranges from 0 to 10, with lower scores indicating better physical function. A negative value in BASFI change from Baseline indicates an improvement from Baseline. The higher the negative value the better the improvement.

The Bath Ankylosing Spondylitis Functional Index (BASFI) assesses physical function in comprising 10 items relating to activities during the past week. Each item ranges from 0 ('Easy') to 10 ('Impossible'). The BASFI is the mean of the 10 scores such that the total score ranges from 0 to 10, with lower scores indicating better physical function. A negative value in BASFI change from Baseline indicates an improvement from Baseline. The higher the negative value the better the improvement.

The Bath Ankylosing Spondylitis Functional Index (BASFI) assesses physical function in comprising 10 items relating to activities during the past week. Each item ranges from 0 ('Easy') to 10 ('Impossible'). The BASFI is the mean of the 10 scores such that the total score ranges from 0 to 10, with lower scores indicating better physical function. A negative value in BASFI change from Baseline indicates an improvement from Baseline. The higher the negative value the better the improvement.

Nocturnal spinal pain experienced by ankylosing spondylitis (AS) subjects is measured by one question: pain in the spine at night due to AS?. When responding, the subject is to consider the average amount of pain in the preceding week. It is assessed on a numerical scale (0 to 10 units). A lower score indicates less pain and an improvement of the outcome.

Nocturnal spinal pain experienced by ankylosing spondylitis (AS) subjects is measured by one question: pain in the spine at night due to AS?. When responding, the subject is to consider the average amount of pain in the preceding week. It is assessed on a numerical scale (0 to 10 units). A lower score indicates less pain and an improvement of the outcome.

Nocturnal spinal pain experienced by ankylosing spondylitis (AS) subjects is measured by one question: pain in the spine at night due to AS?. When responding, the subject is to consider the average amount of pain in the preceding week. It is assessed on a numerical scale (0 to 10 units). A lower score indicates less pain and an improvement of the outcome.

The Ankylosing Spondylitis Quality of Life (ASQoL), a validated disease-specific 18-item questionnaire, has been developed specifically for measuring health-related quality of life (HRQoL) in subjects with ankylosing spondylitis (AS) and has shown to be responsive in axial spondyloarthritis (axSpA). The ASQoL score ranges from 0 to 18 with a higher score indicating worse HRQoL.

The Ankylosing Spondylitis Quality of Life (ASQoL), a validated disease-specific 18-item questionnaire, has been developed specifically for measuring health-related quality of life (HRQoL) in subjects with ankylosing spondylitis (AS) and has shown to be responsive in axial spondyloarthritis (axSpA). The ASQoL score ranges from 0 to 18 with a higher score indicating worse HRQoL.

The Ankylosing Spondylitis Quality of Life (ASQoL), a validated disease-specific 18-item questionnaire, has been developed specifically for measuring health-related quality of life (HRQoL) in subjects with ankylosing spondylitis (AS) and has shown to be responsive in axial spondyloarthritis (axSpA). The ASQoL score ranges from 0 to 18 with a higher score indicating worse HRQoL.

There are 8 Short-Form 36-item Health Survey (SF-36) domain scores. In addition to domain scores, the Physical Component Summary (PCS) scores are calculated from the 8 domains. Each of the 8 domain scores and the component summary scores ranging from 0 to 100, with higher scores indicating better health status. A larger positive value in change from Baseline indicates an improvement.

There are 8 Short-Form 36-item Health Survey (SF-36) domain scores. In addition to domain scores, the Physical Component Summary (PCS) scores are calculated from the 8 domains. Each of the 8 domain scores and the component summary scores ranging from 0 to 100, with higher scores indicating better health status. A larger positive value in change from Baseline indicates an improvement.

The Bath Ankylosing Spondylitis Disease Metrology Index (BASMI) characterizes the spinal mobility of subjects with axial Spondyloarthritis (SpA) and Ankylosing Spondylitis (AS). It is a disease-specific measure consisting of 5 clinical measures to reflect subject axial status: cervical rotation; tragus to wall distance; lateral lumbar flexion; lumbar flexion (modified Schober test); intermalleolar distance. According to the linear definition of the BASMI a score of 0 to 10 is calculated for each item based on the measurement. The mean of the 5 scores provides the BASMI score. The higher the BASMI score the more severe the patient's limitation of movement due to their axial SpA. A negative value in BASMI change from Baseline indicates an improvement from Baseline. The higher the negative value the better the improvement.

The Bath Ankylosing Spondylitis Disease Metrology Index (BASMI) characterizes the spinal mobility of subjects with axial Spondyloarthritis (SpA) and Ankylosing Spondylitis (AS). It is a disease-specific measure consisting of 5 clinical measures to reflect subject axial status: cervical rotation; tragus to wall distance; lateral lumbar flexion; lumbar flexion (modified Schober test); intermalleolar distance. According to the linear definition of the BASMI a score of 0 to 10 is calculated for each item based on the measurement. The mean of the sum of the 5 scores provides the BASMI score. The higher the BASMI score the more severe the patient's limitation of movement due to their axial SpA. A negative value in BASMI change from Baseline indicates an improvement from Baseline. The higher the negative value the better the improvement.

The Bath Ankylosing Spondylitis Disease Metrology Index (BASMI) characterizes the spinal mobility of subjects with axial Spondyloarthritis (SpA) and Ankylosing Spondylitis (AS). It is a disease-specific measure consisting of 5 clinical measures to reflect subject axial status: cervical rotation; tragus to wall distance; lateral lumbar flexion; lumbar flexion (modified Schober test); intermalleolar distance. According to the linear definition of the BASMI a score of 0 to 10 is calculated for each item based on the measurement. The mean of the sum of the 5 scores provides the BASMI score. The higher the BASMI score the more severe the patient's limitation of movement due to their axial SpA. A negative value in BASMI change from Baseline indicates an improvement from Baseline. The higher the negative value the better the improvement.

The Maastricht Ankylosing Spondylitis Enthesitis (MASES) is an index that measures the severity (ie, intensity and extent) of enthesitis through the assessment of 13 entheses (bilateral costochondral 1, costochondral 7, anterior superior iliac spine, posterior iliac spine, iliac crest and proximal insertion of the Achilles tendon sites, and the fifth lumbar vertebral body spinous process) each scored as 0 or 1 and then summed for a possible score of 0 to 13. A higher score indicates worsening.

The Maastricht Ankylosing Spondylitis Enthesitis (MASES) is an index that measures the severity (ie, intensity and extent) of enthesitis through the assessment of 13 entheses (bilateral costochondral 1, costochondral 7, anterior superior iliac spine, posterior iliac spine, iliac crest and proximal insertion of the Achilles tendon sites, and the fifth lumbar vertebral body spinous process) each scored as 0 or 1 and then summed for a possible score of 0 to 13. A higher score indicates worsening.

The Maastricht Ankylosing Spondylitis Enthesitis (MASES) is an index that measures the severity (ie, intensity and extent) of enthesitis through the assessment of 13 entheses (bilateral costochondral 1, costochondral 7, anterior superior iliac spine, posterior iliac spine, iliac crest and proximal insertion of the Achilles tendon sites, and the fifth lumbar vertebral body spinous process) each scored as 0 or 1 and then summed for a possible score of 0 to 13. A higher score indicates worsening.

There are 8 Short-Form 36-item Health Survey (SF-36) domain scores. In addition to domain scores, the Physical Component Summary (PCS) scores are calculated from the 8 domains. Each of the 8 domain scores and the component summary scores ranging from 0 to 100, with higher scores indicating better health status. A larger positive value in change from Baseline indicates an improvement.