Study to Evaluate Maintenance of Sustained Remission of axSpA With CZP Compared to Placebo (C-OPTIMISE)

• ClinicalTrials.gov Identifier: NCT02505542
• Recruitment Status: Completed
• First Posted: July 22, 2015
• Results First Posted: April 21, 2020
• Last Update Posted: December 17, 2020
• Sponsor: UCB BIOSCIENCES GmbH
• Collaborator: Parexel
• Information provided by (Responsible Party): UCB Pharma ( UCB BIOSCIENCES GmbH )

• Study Type: Interventional
• Study Design: Allocation: Randomized; Intervention Model: Parallel Assignment; Masking: Double (Participant, Investigator); Primary Purpose: Treatment
• Conditions: Axial Spondyloarthrithis; Ankylosing Spondylitis
• Interventions: Biological: Certolizumab Pegol; Other: Placebo
• Enrollment: 736

Participant Flow

Recruitment Details	The study started to enroll patients in July 2015 and concluded in April 2019.
Pre-assignment Details	The study included 2 parts: Part A with a Screening Period (up to 5 Weeks) and an Open-Label Period (Week 0 to Week 48) and Part B with a Double-Blind Period (Week 48 to Week 96) and a Safety Follow-Up Period (10 weeks after the last dose of study medication). Participant Flow refers to the Open-Label Set.

Arm/Group Title	Certolizumab Pegol Open-Label	Placebo Double-Blind	Certolizumab Pegol 200 mg Q2W Double-Blind	Certolizumab Pegol 200 mg Q4W Double-Blind
Arm/Group Description	Participants in this arm received certolizumab pegol (CZP) 400 mg subcutaneous (sc) on Weeks 0, 2 and 4, followed by 200 mg CZP sc every 2 weeks (Q2W) from Week 6 to Week 48 (Part A). Participants in sustained remission at Week 48 were eligible for randomization into Part B.	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind.
Period Title: Part A: Open-Label Period
Started	736	0	0	0
Completed	659	0	0	0
Not Completed	77	0	0	0
Reason Not Completed
Adverse Event	31	0	0	0
Lack of Efficacy	5	0	0	0
Protocol Violation	1	0	0	0
Lost to Follow-up	5	0	0	0
Withdrawal by Subject	27	0	0	0
New medical history available	1	0	0	0
Participant did not attend week 48 visit	1	0	0	0
Pregnancy	2	0	0	0
Sponsor directive	1	0	0	0
Medical monitor decision	1	0	0	0
Screening failure (detected too late)	1	0	0	0
Non-compliance	1	0	0	0
Period Title: Completed Part A, Did Not Enter Part B
Started	659	0	0	0
Completed	313	0	0	0
Not Completed	346	0	0	0
Reason Not Completed
Lack of Efficacy	2	0	0	0
Withdrawal by Subject	3	0	0	0
The subject was not eligible for Part B	341	0	0	0
Period Title: Part B: Double-Blind Period
Started	0	104	104	105
Started Escape Period	0	73	7	15
Completed	0	92	95	98
Not Completed	0	12	9	7
Reason Not Completed
Adverse Event	0	0	1	3
Lost to Follow-up	0	0	0	1
Withdrawal by Subject	0	8	7	2
Planning pregnancy	0	1	0	0
Week 94 missed	0	0	1	0
Patient was moved from the country	0	0	0	1
Lack of Efficacy	0	1	0	0
Miscalculation	0	1	0	0
Subject did not complete all visits	0	1	0	0

Baseline Characteristics

Arm/Group Title		Certolizumab Pegol Open-Label
Arm/Group Description		Participants in this arm received certolizumab pegol (CZP) 400 mg subcutaneous (sc) on Weeks 0, 2 and 4, followed by 200 mg CZP sc every 2 weeks (Q2W) from Week 6 to Week 48 (Part A). Participants in sustained remission at Week 48 were eligible for randomization into Part B.
Overall Number of Baseline Participants		736
Baseline Analysis Population Description		Baseline Characteristics refer to the The Open-Label Set (OLS) which consisted of all study participants who received at least 1 dose of investigational medicinal product (IMP) in the Open-Label Period of the study (Part A).
Age, Categorical; Measure Type: Count of Participants; Unit of measure: Participants
	Number Analyzed	736 participants
	<=18 years	7 1.0%
	Between 18 and 65 years	729 99.0%
	>=65 years	0 0.0%
Age, Continuous; Mean (Standard Deviation); Unit of measure: Years
	Number Analyzed	736 participants
		32.9 (7.0)
Sex: Female, Male; Measure Type: Count of Participants; Unit of measure: Participants
	Number Analyzed	736 participants
	Female	222 30.2%
	Male	514 69.8%
Race/Ethnicity, Customized; Measure Type: Count of Participants; Unit of measure: Participants
	Number Analyzed	736 participants
	American indian/alaskan native	2 0.3%
	Asian	38 5.2%
	Black	1 0.1%
	White	681 92.5%
	Other/Mixed	5 0.7%
	Missing	9 1.2%

Outcome Measures

1. Primary Outcome

Title	Percentage of Participants in Part B Who Did Not Experienced a Flare
Description	A participant was considered to have experienced a flare if the participant had an Ankylosing spondylitis disease activity score (ASDAS) greater or equal to (≥) 2.1 at 2 consecutive visits or an ASDAS greater than (>) 3.5 at any visit during Part B up until Week 96. A participant qualified for Part B only if he achieved sustained remission after 48 weeks of Open-Label certolizumab pegol (CZP) treatment. Sustained remission was achieved when a participant had an ASDAS less than (<) 1.3 at Week 32 or Week 36 (if ASDAS < 1.3 at Week 32, it must have been < 2.1 at Week 36; if ASDAS < 2.1 at Week 32, it must have been < 1.3 at Week 36) and an ASDAS < 1.3 at Week 48. Missing data were handled using non-response imputation (NRI) methods.
Time Frame	From Week 48 to Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Measure Type: Number; Number (95% Confidence Interval); Unit of Measure: percentage of participants
	20.2; (13.0 to 29.2)	83.7; (75.1 to 90.2)	79.0; (70.0 to 86.4)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Odds ratio (and corresponding p-value) resulted from a logistic regression model with factors for treatment, geographic region, and modified New York (mNY) classification for study participants who did not experience a flare. An odds ratio > 1 indicates a study participant on CZP was more likely not to experience a flare than a study participant on placebo. Penalized maximum likelihood approach was used for logistic regression.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	A fixed sequence testing procedure was used whereby the second test (CZP 200 mg Q4W vs PBO) was interpreted as statistically significant only if the first test (CZP 200 mg Q2W vs PBO) was significant at the 0.05 level as well.
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	18.822
	Confidence Interval	(2-Sided) 95%; 9.605 to 38.864
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Odds ratio (and corresponding p-value) resulted from a logistic regression model with factors for treatment, geographic region, and modified New York (mNY) classification for study participants who did not experience a flare. An odds ratio > 1 indicates a study participant on CZP was more likely not to experience a flare than a study participant on placebo. Penalized maximum likelihood approach was used for logistic regression.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	A fixed sequence testing procedure was used whereby the second test (CZP 200 mg Q4W vs PBO) was interpreted as statistically significant only if the first test (CZP 200 mg Q2W vs PBO) was significant at the 0.05 level as well.
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	14.069
	Confidence Interval	(2-Sided) 95%; 7.395 to 27.955
	Estimation Comments	[Not Specified]

2. Secondary Outcome

Title	Percentage of Participants Achieving Sustained Remission at Week 48 in Part A
Description	Sustained remission was achieved when a participant had an ASDAS less than (<) 1.3 at Week 32 or Week 36 (if ASDAS < 1.3 at Week 32, it must have been < 2.1 at Week 36; if ASDAS < 2.1 at Week 32, it must have been < 1.3 at Week 36) and an ASDAS < 1.3 at Week 48. Missing data were handled using non-response imputation (NRI) methods.
Time Frame	Week 48

Outcome Measure Data

Analysis Population Description

The Open-Label Set (OLS) consisted of all study participants who received at least 1 dose of investigational medicinal product (IMP) in the Open-Label Period of the study (Part A).

Arm/Group Title	Certolizumab Pegol Open-Label (OLS)
Arm/Group Description:	Participants in this arm received certolizumab pegol (CZP) 400 mg subcutaneous (sc) on Weeks 0, 2 and 4, followed by 200 mg CZP sc every 2 weeks (Q2W) from Week 6 to Week 48 (Part A). Participants in sustained remission at Week 48 were eligible for randomization into Part B. Participants formed the Open-Label Set (OLS).
Overall Number of Participants Analyzed	736
Measure Type: Number; Number (95% Confidence Interval); Unit of Measure: percentage of participants
	43.9; (40.3 to 47.6)

3. Secondary Outcome

Title	Percentage of Participants in Ankylosing Spondylitis Disease Activity Score (ASDAS) Disease Activity Categories at Week 48 in Part A
Description	The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI Q2 result) 0.058 x Duration of morning stiffness (BASDAI Q6 result) 0.110 x PGADA (Patient's Global Assessment of Disease Activity) 0.073 x Peripheral pain/swelling (BASDAI Q3 result) 0.579 × (natural logarithm [ln] of the (CRP [mg/L] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue were all assessed on a numerical scale (0 to 10 units). Disease activity was measured by categorical response variables: ASDAS-Inactive Disease (ASDAS-ID): ASDAS < 1.3; ASDAS-Moderate Disease (ASDAS-MD): ASDAS ≥ 1.3, < 2.1; ASDAS-High Disease activity (ASDAS-HD): ASDAS ≥ 2.1, ≤ 3.5; ASDAS-very High Disease activity (ASDAS-vHD): ASDAS > 3.5 Missing data were handled using last observation carried forward (LOCF) methods.
Time Frame	Week 48

Outcome Measure Data

Analysis Population Description

The Open-Label Set (OLS) consisted of all study participants who received at least 1 dose of IMP in the Open-Label Period of the study (Part A).

Arm/Group Title	Certolizumab Pegol Open-Label (OLS)
Arm/Group Description:	Participants in this arm received certolizumab pegol (CZP) 400 mg subcutaneous (sc) on Weeks 0, 2 and 4, followed by 200 mg CZP sc every 2 weeks (Q2W) from Week 6 to Week 48 (Part A). Participants in sustained remission at Week 48 were eligible for randomization into Part B. Participants formed the Open-Label Set (OLS).
Overall Number of Participants Analyzed	736
Measure Type: Number; Unit of Measure: percentage of participants
ASDAS-ID	52.5
ASDAS-MD	22.8
ASDAS-HD	18.9
ASDAS-vHD	5.9

4. Secondary Outcome

Title	Percentage of Participants in Ankylosing Spondylitis Disease Activity Score (ASDAS) Clinical Improvement Categories at Week 48 in Part A
Description	The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI Q2 result) 0.058 x Duration of morning stiffness (BASDAI Q6 result) 0.110 x PGADA (Patient's Global Assessment of Disease Activity) 0.073 x Peripheral pain/swelling (BASDAI Q3 result) 0.579 × (natural logarithm [ln] of the (CRP [mg/L] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue were all assessed on a numerical scale (0 to 10 units). ASDAS improvement was measured by binary response variables: ASDAS-CII: ASDAS reduction (improvement) of ≥ 1.1 relative to Baseline; ASDAS-MI: ASDAS reduction (improvement) of ≥ 2.0 relative to Baseline Missing data were handled using non-response imputation (NRI) methods.
Time Frame	Week 48

Outcome Measure Data

Analysis Population Description

The Open-Label Set (OLS) consisted of all study participants who received at least 1 dose of IMP in the Open-Label Period of the study (Part A).

Arm/Group Title	Certolizumab Pegol Open-Label (OLS)
Arm/Group Description:	Participants in this arm received certolizumab pegol (CZP) 400 mg subcutaneous (sc) on Weeks 0, 2 and 4, followed by 200 mg CZP sc every 2 weeks (Q2W) from Week 6 to Week 48 (Part A). Participants in sustained remission at Week 48 were eligible for randomization into Part B. Participants formed the Open-Label Set (OLS).
Overall Number of Participants Analyzed	736
Measure Type: Number; Unit of Measure: percentage of participants
ASDAS-CII	76.6
ASDAS-MI	56.1

5. Secondary Outcome

Title	Time to Flare in Part B
Description	For those who met the criteria for flare (see primary efficacy variable), the time to flare was the length in days from randomization in Part B until the visit at which the criteria for flare were met. Participants who discontinued the study without meeting the criteria for flare were counted as experiencing a flare at the time of their last study visit. The time to flare was analyzed using Kaplan-Meier methods. If Kaplan-Meier Estimate was NA for all estimates then more than 75 % failed to meet the flare condition. Missing data were handled using non-response imputation (NRI) methods.
Time Frame	From Week 48 to Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Median (Inter-Quartile Range); Unit of Measure: days
	113; (84 to 257)	371; (371 to 371)	NA [1]; (NA to NA)

[1]

Values were not calculated since more than 75 % failed to meet the flare condition.

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	P-values were from stratified log-rank test comparing the Certolizumab pegol 200 mg Q2W Double-Blind (RS) group with the Placebo Double-Blind (RS) group (Geographic region and modified New York (mNY) classification were used as stratification factors).
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Log Rank
	Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	P-values were from stratified log-rank test comparing the Certolizumab pegol 200 mg Q4W Double-Blind (RS) group with the Placebo Double-Blind (RS) group (Geographic region and modified New York (mNY) classification were used as stratification factors).
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Log Rank
	Comments	[Not Specified]

6. Secondary Outcome

Title	Percentage of Participants in Ankylosing Spondylitis Disease Activity Score (ASDAS) Disease Activity Categories at Week 96 in Part B
Description	The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI Q2 result) 0.058 x Duration of morning stiffness (BASDAI Q6 result) 0.110 x PGADA (Patient's Global Assessment of Disease Activity) 0.073 x Peripheral pain/swelling (BASDAI Q3 result) 0.579 × (natural logarithm [ln] of the (CRP [mg/L] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue were all assessed on a numerical scale (0 to 10 units). Disease activity was measured by categorical response variables: ASDAS-Inactive Disease (ASDAS-ID): ASDAS < 1.3; ASDAS-Moderate Disease (ASDAS-MD): ASDAS ≥ 1.3, < 2.1; ASDAS-High Disease activity (ASDAS-HD): ASDAS ≥ 2.1, ≤ 3.5; ASDAS-very High Disease activity (ASDAS-vHD): ASDAS > 3.5
Time Frame	Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Measure Type: Number; Unit of Measure: percentage of participants
ASDAS-ID	58.3	86.2	69.9
ASDAS-MD	25.0	13.8	22.9
ASDAS-HD	16.7	0	7.2
ASDAS-vHD	0	0	0

7. Secondary Outcome

Title	Percentage of Participants in Ankylosing Spondylitis Disease Activity Score (ASDAS) Clinical Improvement Categories at Week 96 in Part B
Description	The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI Q2 result) 0.058 x Duration of morning stiffness (BASDAI Q6 result) 0.110 x PGADA (Patient's Global Assessment of Disease Activity) 0.073 x Peripheral pain/swelling (BASDAI Q3 result) 0.579 × (natural logarithm [ln] of the (CRP [mg/L] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue were all assessed on a numerical scale (0 to 10 units). ASDAS improvement was measured by binary response variables: ASDAS-CII: ASDAS reduction (improvement) of ≥ 1.1 relative to Baseline; ASDAS-MI: ASDAS reduction (improvement) of ≥ 2.0 relative to Baseline Missing data were handled using non-response imputation (NRI) methods.
Time Frame	Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Measure Type: Number; Unit of Measure: percentage of participants
ASDAS-CII	21.2	82.7	75.2
ASDAS-MI	10.6	67.3	58.1

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and modified New York (mNY) classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	17.940
	Confidence Interval	(2-Sided) 95%; 8.950 to 35.961
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and modified New York (mNY) classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	11.385
	Confidence Interval	(2-Sided) 95%; 5.952 to 21.778
	Estimation Comments	[Not Specified]

Statistical Analysis 3

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and modified New York (mNY) classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	17.653
	Confidence Interval	(2-Sided) 95%; 8.333 to 37.399
	Estimation Comments	[Not Specified]

Statistical Analysis 4

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and modified New York (mNY) classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	11.863
	Confidence Interval	(2-Sided) 95%; 5.670 to 24.822
	Estimation Comments	[Not Specified]

8. Secondary Outcome

Title	Percentage of Participants With Axial SpondyloArthritis International Society 20 % Response Criteria (ASAS20) Response at Week 96 in Part B
Description	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 Numeric Rating Scale (NRS) in at least 3 of the 4 domains: Patient's Global Assessment of Disease Activity (PGADA), Pain assessment (total spinal pain NRS scores), 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 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]. Missing data were handled using non-response imputation (NRI) methods.
Time Frame	Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Measure Type: Number; Unit of Measure: percentage of participants
	23.1	85.6	78.1

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	20.205
	Confidence Interval	(2-Sided) 95%; 9.851 to 41.439
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	12.070
	Confidence Interval	(2-Sided) 95%; 6.275 to 23.218
	Estimation Comments	[Not Specified]

9. Secondary Outcome

Title	Percentage of Participants With Axial SpondyloArthritis International Society 40 % Response Criteria (ASAS40) Response at Week 96 in Part B
Description	The ASAS40 response was defined as a relative improvement 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: Patient's Global Assessment of Disease Activity (PGADA), Pain assessment (total spinal pain NRS scores), 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. Missing data were handled using non-response imputation (NRI) methods.
Time Frame	Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Measure Type: Number; Unit of Measure: percentage of participants
	21.2	84.6	73.3

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	20.891
	Confidence Interval	(2-Sided) 95%; 10.210 to 42.744
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	10.377
	Confidence Interval	(2-Sided) 95%; 5.456 to 19.738
	Estimation Comments	[Not Specified]

10. Secondary Outcome

Title	Percentage of Participants With Axial SpondyloArthritis International Society (ASAS) 5/6 Response Criteria Response at Week 96 in Part B
Description	The ASAS 5/6 response was defined as achieving at least 20 % improvement in 5 of 6 domains, including the 4 domains defined for ASAS20 as well as spinal mobility (lateral spinal flexion) and C-reactive Protein (CRP). Missing data were handled using non-response imputation (NRI) methods.
Time Frame	Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Measure Type: Number; Unit of Measure: percentage of participants
	12.5	70.2	62.9

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	16.900
	Confidence Interval	(2-Sided) 95%; 8.211 to 34.785
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	12.072
	Confidence Interval	(2-Sided) 95%; 5.954 to 24.476
	Estimation Comments	[Not Specified]

11. Secondary Outcome

Title	Percentage of Participants With Axial SpondyloArthritis International Society (ASAS) Partial Remission (PR) Response Criteria Response at Week 96 in Part B
Description	The ASAS partial remission (PR) response was defined as a score of ≤ 2 units on a 0 to 10 unit scale in all 4 domains listed for ASAS20. Missing data were handled using non-response imputation (NRI) methods.
Time Frame	Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Measure Type: Number; Unit of Measure: percentage of participants
	17.3	77.9	70.5

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	17.082
	Confidence Interval	(2-Sided) 95%; 8.561 to 34.085
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	11.503
	Confidence Interval	(2-Sided) 95%; 5.939 to 22.278
	Estimation Comments	[Not Specified]

12. Secondary Outcome

Title	Change From Baseline in Ankylosing Spondylitis Disease Activity Score (ASDAS) at Week 96 in Part B
Description	The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI Q2 result) 0.058 x Duration of morning stiffness (BASDAI Q6 result) 0.110 x PGADA (Patient's Global Assessment of Disease Activity) 0.073 x Peripheral pain/swelling (BASDAI Q3 result) 0.579 × (natural logarithm [ln] of the (CRP [mg/L] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue were all assessed on a numerical scale (0 to 10 units). There is a minimum score of 0.636 for the total ASDAS score, but no defined upper score. Based on the formula even in the situation that the CRP is normal, any value below 4 is recorded as "below the limit of quantification" (BLQ) and a value of BLQ/2=2 was prespecified. This assumption is triggering the lowest possible value of 0.636. The change from Part B Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From Week 48 to Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Least Squares Mean (Standard Error); Unit of Measure: scores on a scale
	1.66 (0.110)	0.24 (0.077)	0.45 (0.077)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	An mixed model with repeated measures (MMRM) analysis on all observed post-baseline data with the following fixed-effect covariates was used: treatment, geographical region, mNY classification, Part B Baseline value, and visit as fixed-effect factors, as well as treatment group by visit interaction and Part B Baseline value by visit interaction.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Mixed Models Analysis
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-1.42
	Confidence Interval	(2-Sided) 95%; -1.66 to -1.17
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.126
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	An mixed model with repeated measures (MMRM) analysis on all observed post-baseline data with the following fixed-effect covariates was used: treatment, geographical region, mNY classification, Part B Baseline value, and visit as fixed-effect factors, as well as treatment group by visit interaction and Part B Baseline value by visit interaction.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Mixed Models Analysis
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-1.21
	Confidence Interval	(2-Sided) 95%; -1.45 to -0.96
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.126
	Estimation Comments	[Not Specified]

13. Secondary Outcome

Title	Change From Baseline in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) at Week 96 in Part B
Description	The 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 scores ranges from 0 to 10, with lower scores indicating lower disease activity. The change from Part B Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From Week 48 to Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Least Squares Mean (Standard Error); Unit of Measure: scores on a scale
	3.02 (0.226)	0.56 (0.176)	0.78 (0.176)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	An mixed model with repeated measures (MMRM) analysis on all observed post-baseline data with the following fixed-effect covariates was used: treatment, geographical region, mNY classification, Part B Baseline value, and visit as fixed-effect factors, as well as treatment group by visit interaction and Part B Baseline value by visit interaction.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Mixed Models Analysis
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-2.46
	Confidence Interval	(2-Sided) 95%; -2.99 to -1.94
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.268
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	An mixed model with repeated measures (MMRM) analysis on all observed post-baseline data with the following fixed-effect covariates was used: treatment, geographical region, mNY classification, Part B Baseline value, and visit as fixed-effect factors, as well as treatment group by visit interaction and Part B Baseline value by visit interaction.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Mixed Models Analysis
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-2.24
	Confidence Interval	(2-Sided) 95%; -2.77 to -1.72
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.267
	Estimation Comments	[Not Specified]

14. Secondary Outcome

Title	Change From Baseline in Bath Ankylosing Spondylitis Functional Index (BASFI) at Week 96 in Part B
Description	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 Part B Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From Week 48 to Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Least Squares Mean (Standard Error); Unit of Measure: scores on a scale
	1.90 (0.233)	0.32 (0.198)	0.46 (0.205)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	An mixed model with repeated measures (MMRM) analysis on all observed post-baseline data with the following fixed-effect covariates was used: treatment, geographical region, mNY classification, Part B Baseline value, and visit as fixed-effect factors, as well as treatment group by visit interaction and Part B Baseline value by visit interaction.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Mixed Models Analysis
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-1.57
	Confidence Interval	(2-Sided) 95%; -2.04 to -1.11
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.238
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	An mixed model with repeated measures (MMRM) analysis on all observed post-baseline data with the following fixed-effect covariates was used: treatment, geographical region, mNY classification, Part B Baseline value, and visit as fixed-effect factors, as well as treatment group by visit interaction and Part B Baseline value by visit interaction.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Mixed Models Analysis
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-1.43
	Confidence Interval	(2-Sided) 95%; -1.90 to -0.96
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.238
	Estimation Comments	[Not Specified]

15. Secondary Outcome

Title	Change From Baseline in Bath Ankylosing Spondylitis Metrology Index (BASMI) at Week 96 in Part B
Description	The BASMI 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 was calculated for each item based on the measurement. The mean of the sum of the 5 scores provided the total BASMI score, ranging from 0 to 10. The higher the BASMI score the more severe the patient's limitation of movement due to their axial spondyloarthritis (axSpA). The change from Part B Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From Week 48 to Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Least Squares Mean (Standard Error); Unit of Measure: scores on a scale
	0.21 (0.105)	0.00 (0.065)	-0.03 (0.068)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	An mixed model with repeated measures (MMRM) analysis on all observed post-baseline data with the following fixed-effect covariates was used: treatment, geographical region, mNY classification, Part B Baseline value, and visit as fixed-effect factors, as well as treatment group by visit interaction and Part B Baseline value by visit interaction.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	=0.074
	Comments	[Not Specified]
	Method	Mixed Models Analysis
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-0.20
	Confidence Interval	(2-Sided) 95%; -0.42 to 0.02
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.112
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	An mixed model with repeated measures (MMRM) analysis on all observed post-baseline data with the following fixed-effect covariates was used: treatment, geographical region, mNY classification, Part B Baseline value, and visit as fixed-effect factors, as well as treatment group by visit interaction and Part B Baseline value by visit interaction.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	=0.036
	Comments	[Not Specified]
	Method	Mixed Models Analysis
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-0.24
	Confidence Interval	(2-Sided) 95%; -0.46 to -0.02
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.113
	Estimation Comments	[Not Specified]

16. Secondary Outcome

Title	Percentage of Participants With Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) 50 Response Criteria Response at Week 96 in Part B
Description	The BASDAI50 response was defined as an improvement of at least 50 % in the BASDAI score relative to Baseline. Missing data were handled using non-response imputation (NRI) methods.
Time Frame	Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	104	104	105
Measure Type: Number; Unit of Measure: percentage of participants
	22.1	83.7	77.1

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	18.308
	Confidence Interval	(2-Sided) 95%; 9.084 to 36.898
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Odds ratios (and corresponding p-values) were from a logistic regression model with factors for treatment group, geographical region, and mNY classification.
	Type of Statistical Test	Superiority
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	<0.001
	Comments	[Not Specified]
	Method	Regression, Logistic
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	Odds Ratio (OR)
	Estimated Value	12.020
	Confidence Interval	(2-Sided) 95%; 6.255 to 23.098
	Estimation Comments	[Not Specified]

17. Secondary Outcome

Title	Change From Baseline in Sacroiliac Spondyloarthritis Research Consortium of Canada (SPARCC) Score at Week 96 in Part B
Description	The SPARCC scoring method for lesions found on the Magnetic Resonance Imaging (MRI) is based on an abnormal increased signal on the Short-Tau-Inversion Recovery (STIR) sequence, representing bone marrow edema. Total Sacroiliac (SI) joint SPARCC score can range from 0 to 72 with higher scores indicating higher joint inflammation. The change from Part B Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From Week 48 to Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

The number of participants analyzed reflects Week 96.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	24	79	77
Mean (Standard Deviation); Unit of Measure: scores on a scale
	1.1 (3.6)	0.2 (2.4)	0.6 (3.8)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Only MRIs performed ± 2 weeks around the Week 96 or Early Withdrawal Visit were assigned to Week 96 or Early Withdrawal. Only results of the double-read assessments of the central MRI review were included. The analysis used the average of the scores from the 2 independent reviewers. Whenever an adjudication was present, the average score across all 3 reviewers was used. ANCOVA model with treatment, geographical region, mNY classification, and Part B Baseline as covariates.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	=0.195
	Comments	[Not Specified]
	Method	ANCOVA
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-1.0
	Confidence Interval	(2-Sided) 95%; -2.50 to 0.51
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.76
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Only MRIs performed ± 2 weeks around the Week 96 or Early Withdrawal Visit were assigned to Week 96 or Early Withdrawal. Only results of the double-read assessments of the central MRI review were included. The analysis used the average of the scores from the 2 independent reviewers. Whenever an adjudication was present, the average score across all 3 reviewers was used. ANCOVA model with treatment, geographical region, mNY classification, and Part B Baseline as covariates.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	=0.432
	Comments	[Not Specified]
	Method	ANCOVA
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-0.6
	Confidence Interval	(2-Sided) 95%; -2.11 to 0.91
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.76
	Estimation Comments	[Not Specified]

18. Secondary Outcome

Title	Change From Baseline in Spine Ankylosing Spondylitis Spine Magnetic Resonance Imaging Score for Disease Activity (ASspIMRI-a) in the Berlin Modification Score at Week 96 in Part B
Description	The Berlin modification of the ASspiMRI-a is a scoring system with a concentration on Short-Tau-Inversion Recovery (STIR) sequences without other fat saturation techniques. It quantifies changes in 23 Vertebral Units (VU) of the spine. Active inflammation was scored by grading the degree of bone marrow edema from 0 to 3 in 1 dimension on 1 or more consecutive slices that represent the highest level of inflammation in a particular VU. The change from Part B Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From Week 48 to Week 96

Outcome Measure Data

Analysis Population Description

The Randomized Set (RS) consisted of all study participants randomized into Part B of the study.

The number of participants analyzed reflects Week 96.

Arm/Group Title	Placebo Double-Blind (RS)	Certolizumab Pegol 200 mg Q2W Double-Blind (RS)	Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Randomized Set (RS).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the RS.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the RS.
Overall Number of Participants Analyzed	24	79	78
Mean (Standard Deviation); Unit of Measure: scores on a scale
	0.4 (0.9)	0.0 (0.8)	0.0 (0.8)

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q2W Double-Blind (RS)
	Comments	Only MRIs performed ± 2 weeks around the Week 96 or Early Withdrawal Visit were assigned to Week 96 or Early Withdrawal. Only results of the double-read assessments of the central MRI review were included. The analysis used the average of the scores from the 2 independent reviewers. Whenever an adjudication was present, the average score across all 3 reviewers was used. ANCOVA model with treatment, geographical region, mNY classification, and Part B Baseline as covariates.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	=0.040
	Comments	[Not Specified]
	Method	ANCOVA
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-0.4
	Confidence Interval	(2-Sided) 95%; -0.78 to -0.02
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.19
	Estimation Comments	[Not Specified]

Statistical Analysis 2

Statistical Analysis Overview	Comparison Group Selection	Placebo Double-Blind (RS), Certolizumab Pegol 200 mg Q4W Double-Blind (RS)
	Comments	Only MRIs performed ± 2 weeks around the Week 96 or Early Withdrawal Visit were assigned to Week 96 or Early Withdrawal. Only results of the double-read assessments of the central MRI review were included. The analysis used the average of the scores from the 2 independent reviewers. Whenever an adjudication was present, the average score across all 3 reviewers was used. ANCOVA model with treatment, geographical region, mNY classification, and Part B Baseline as covariates.
	Type of Statistical Test	Other
	Comments	[Not Specified]
Statistical Test of Hypothesis	P-Value	=0.074
	Comments	[Not Specified]
	Method	ANCOVA
	Comments	[Not Specified]
Method of Estimation	Estimation Parameter	LS Mean Difference vs Placebo
	Estimated Value	-0.3
	Confidence Interval	(2-Sided) 95%; -0.73 to 0.03
	Parameter Dispersion	Type: Standard Error of the Mean; Value: 0.19
	Estimation Comments	[Not Specified]

19. Secondary Outcome

Title	Percentage of Participants in Ankylosing Spondylitis Disease Activity Score (ASDAS) Disease Activity Categories at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI Q2 result) 0.058 x Duration of morning stiffness (BASDAI Q6 result) 0.110 x PGADA (Patient's Global Assessment of Disease Activity) 0.073 x Peripheral pain/swelling (BASDAI Q3 result) 0.579 × (natural logarithm [ln] of the (CRP [mg/L] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue were all assessed on a numerical scale (0 to 10 units). Disease activity was measured by categorical response variables: ASDAS-Inactive Disease (ASDAS-ID): ASDAS < 1.3; ASDAS-Moderate Disease (ASDAS-MD): ASDAS ≥ 1.3, < 2.1; ASDAS-High Disease activity (ASDAS-HD): ASDAS ≥ 2.1, ≤ 3.5; ASDAS-very High Disease activity (ASDAS-vHD): ASDAS > 3.5
Time Frame	Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	73	7	15
Measure Type: Number; Unit of Measure: percentage of participants
ASDAS-ID	63.4	16.7	60.0
ASDAS-MD	26.8	50.0	20.0
ASDAS-HD	8.5	33.3	20.0
ASDAS-vHD	1.4	0	0

20. Secondary Outcome

Title	Percentage of Participants in Ankylosing Spondylitis Disease Activity Score (ASDAS) Clinical Improvement Categories at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI Q2 result) 0.058 x Duration of morning stiffness (BASDAI Q6 result) 0.110 x PGADA (Patient's Global Assessment of Disease Activity) 0.073 x Peripheral pain/swelling (BASDAI Q3 result) 0.579 × (natural logarithm [ln] of the (CRP [mg/L] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue were all assessed on a numerical scale (0 to 10 units). ASDAS improvement was measured by binary response variables: ASDAS-CII: ASDAS reduction (improvement) of ≥ 1.1 relative to Baseline; ASDAS-MI: ASDAS reduction (improvement) of ≥ 2.0 relative to Baseline
Time Frame	Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	73	7	15
Measure Type: Number; Unit of Measure: percentage of participants
ASDAS-CII	84.5	16.7	46.7
ASDAS-MI	49.3	0	13.3

21. Secondary Outcome

Title	Percentage of Participants With Axial SpondyloArthritis International Society 20 % Response Criteria (ASAS20) Response at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	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 Numeric Rating Scale (NRS) in at least 3 of the 4 domains: Patient's Global Assessment of Disease Activity (PGADA), Pain assessment (total spinal pain NRS scores), 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 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].
Time Frame	Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	73	7	15
Measure Type: Number; Unit of Measure: percentage of participants
	83.3	50.0	64.3

22. Secondary Outcome

Title	Percentage of Participants With Axial SpondyloArthritis International Society 40 % Response Criteria (ASAS40) Response at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The ASAS40 response was defined as a relative improvement 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: Patient's Global Assessment of Disease Activity (PGADA), Pain assessment (total spinal pain NRS scores), 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.
Time Frame	Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	73	7	15
Measure Type: Number; Unit of Measure: percentage of participants
	69.4	16.7	50.0

23. Secondary Outcome

Title	Percentage of Participants With Axial SpondyloArthritis International Society (ASAS) 5/6 Response Criteria Response at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The ASAS 5/6 response was defined as achieving at least 20 % improvement in 5 of 6 domains, including the 4 domains defined for ASAS20 as well as spinal mobility (lateral spinal flexion) and C-reactive Protein (CRP).
Time Frame	Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	73	7	15
Measure Type: Number; Unit of Measure: percentage of participants
	60.6	16.7	7.1

24. Secondary Outcome

Title	Percentage of Participants With Axial SpondyloArthritis International Society (ASAS) Partial Remission (PR) Response Criteria Response at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The ASAS partial remission (PR) response was defined as a score of ≤ 2 units on a 0 to 10 unit scale in all 4 domains listed for ASAS20.
Time Frame	Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	73	7	15
Measure Type: Number; Unit of Measure: percentage of participants
	66.7	16.7	50.0

25. Secondary Outcome

Title	Change From Baseline in Ankylosing Spondylitis Disease Activity Score (ASDAS) at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The ASDAS was calculated as the sum of the following components: 0.121 x Back pain (BASDAI Q2 result) 0.058 x Duration of morning stiffness (BASDAI Q6 result) 0.110 x PGADA (Patient's Global Assessment of Disease Activity) 0.073 x Peripheral pain/swelling (BASDAI Q3 result) 0.579 × (natural logarithm [ln] of the (CRP [mg/L] + 1)) Back pain, PGADA, duration of morning stiffness, peripheral pain/swelling and fatigue were all assessed on a numerical scale (0 to 10 units). There is a minimum score of 0.636 for the total ASDAS score, but no defined upper score. Based on the formula even in the situation that the CRP is normal, any value below 4 is recorded as "below the limit of quantification" (BLQ) and a value of BLQ/2=2 was prespecified. This assumption is triggering the lowest possible value of 0.636. The change from Part B Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From time of flare to Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

The number of participants analyzed reflects Escape Week 12.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	71	6	15
Mean (Standard Deviation); Unit of Measure: scores on a scale
	-2.18 (1.13)	-0.56 (0.64)	-0.83 (0.94)

26. Secondary Outcome

Title	Change From Baseline in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The 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 scores ranges from 0 to 10, with lower scores indicating lower disease activity. The change from flare Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From time of flare to Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

The number of participants analyzed reflects Escape Week 12.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	72	6	15
Mean (Standard Deviation); Unit of Measure: scores on a scale
	-3.75 (2.52)	-1.55 (1.05)	-2.29 (2.35)

27. Secondary Outcome

Title	Change From Baseline in Bath Ankylosing Spondylitis Functional Index (BASFI) at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	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 flare Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From time of flare to Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

The number of participants analyzed reflects Escape Week 12.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	72	6	14
Mean (Standard Deviation); Unit of Measure: scores on a scale
	-2.52 (2.46)	-0.72 (0.70)	-1.83 (2.38)

28. Secondary Outcome

Title	Change From Baseline in Bath Ankylosing Spondylitis Metrology Index (BASMI) at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The BASMI 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 was calculated for each item based on the measurement. The mean of the sum of the 5 scores provided the total BASMI score, ranging from 0 to 10. The higher the BASMI score the more severe the patient's limitation of movement due to their axial spondyloarthritis (axSpA). The change from flare Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From time of flare to Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

The number of participants analyzed reflects Escape Week 12.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	67	6	15
Mean (Standard Deviation); Unit of Measure: scores on a scale
	-0.43 (0.58)	-0.27 (0.35)	-0.26 (0.30)

29. Secondary Outcome

Title	Change From Baseline in Sacroiliac Spondyloarthritis Research Consortium of Canada (SPARCC) Score at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The SPARCC scoring method for lesions found on the Magnetic Resonance Imaging (MRI) is based on an abnormal increased signal on the Short-Tau-Inversion Recovery (STIR) sequence, representing bone marrow edema. Total Sacroiliac (SI) joint SPARCC score can range from 0 to 72 with higher scores indicating higher joint inflammation. The change from flare Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From time of flare to Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

The number of participants analyzed reflects Escape Week 12.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	48	2	12
Mean (Standard Deviation); Unit of Measure: scores on a scale
	-9.3 (13.2)	0.0 (0.0)	0.2 (3.1)

30. Secondary Outcome

Title	Change From Baseline in Spine Ankylosing Spondylitis Spine Magnetic Resonance Imaging Score for Activity (ASspIMRI-a) in the Berlin Modification Score at Escape Week 12 for Participants Who Experienced a Flare in Part B
Description	The Berlin modification of the ASspiMRI-a is a scoring system with a concentration on Short-Tau-Inversion Recovery (STIR) sequences without other fat saturation techniques. It quantifies changes in 23 Vertebral Units (VU) of the spine. Active inflammation was scored by grading the degree of bone marrow edema from 0 to 3 in 1 dimension on 1 or more consecutive slices that represent the highest level of inflammation in a particular VU. The change from flare Baseline is calculated, a negative value indicating improvement and a positive value worsening.
Time Frame	From time of flare to Escape Week 12

Outcome Measure Data

Analysis Population Description

The Flared Set (FS) consisted of all study participants from the RS who experienced a flare in Part B.

The number of participants analyzed reflects Escape Week 12.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (FS)	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (FS)
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Flared Set (FS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the FS.
Overall Number of Participants Analyzed	48	2	12
Mean (Standard Deviation); Unit of Measure: scores on a scale
	-2.3 (4.6)	0.0 (0.0)	-0.3 (1.0)

31. Secondary Outcome

Title	Certolizumab Pegol (CZP) Plasma Concentration During the Study
Description	CZP plasma concentration was measured in micrograms per milliliter (μg/mL). Blood sample measurements that were deemed to be below the level of quantification, were set to half the lower level of quantification (LLOQ) for analysis purposes. Summary statistics were only displayed if at least two-thirds of the values were above the LLOQ and if n was greater or equal to (>=) 4. The primary purpose of the study was to evaluate treatment options for axSpA patients after being in sustained remission. Hence, one of the objectives was to evaluate the PK of these patients. The CZP plasma concentration of the patients that did not reach sustained remission were therefore not analysed, and the Pharmacokinetic Set A as described in the protocol was removed from the SAP.
Time Frame	From Week 0 until the Safety Follow-up Visit (10 weeks after the last dose of study medication)

Outcome Measure Data

Analysis Population Description

The Pharmacokinetic Set B (PKSB) consisted of all study participants from the Safety Set Part B (SSB) who provided at least 1 PK sample during Part B.

Arm/Group Title		Placebo Double-Blind (PKSB)	Certolizumab Pegol 200 mg Q2W Double-Blind (PKSB)	Certolizumab Pegol 200 mg Q4W Double-Blind (PKSB)
Arm/Group Description:		Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Pharmacokinetic Set B (PKSB).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the PKSB.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the PKSB.
Overall Number of Participants Analyzed		101	102	105
Geometric Mean (Geometric Coefficient of Variation); Unit of Measure: μg/mL
Part A Baseline	Number Analyzed	99 participants	101 participants	105 participants
		NA [1]; (NA%)	NA [1]; (NA%)	NA [1]; (NA%)
Week 4	Number Analyzed	101 participants	100 participants	104 participants
		48.71; (85.76%)	53.39; (30.93%)	48.92; (43.17%)
Week 12	Number Analyzed	100 participants	101 participants	105 participants
		30.91; (89.23%)	31.74; (50.79%)	30.69; (56.82%)
Week 24	Number Analyzed	100 participants	101 participants	104 participants
		26.31; (135.58%)	30.23; (46.57%)	28.96; (58.38%)
Week 48/Part B Baseline	Number Analyzed	98 participants	100 participants	104 participants
		36.28; (74.18%)	36.59; (84.36%)	31.11; (138.29%)
Week 60	Number Analyzed	98 participants	100 participants	105 participants
		NA [2]; (NA%)	27.76; (49.47%)	6.95; (178.27%)
Week 72	Number Analyzed	76 participants	95 participants	99 participants
		NA [2]; (NA%)	26.36; (105.58%)	7.61; (176.39%)
Week 84	Number Analyzed	38 participants	91 participants	90 participants
		NA [2]; (NA%)	26.57; (44.90%)	8.00; (113.48%)
Week 96	Number Analyzed	27 participants	86 participants	85 participants
		NA [2]; (NA%)	24.76; (97.60%)	7.16; (131.76%)
Withdrawal Visit	Number Analyzed	4 participants	3 participants	5 participants
		0.81; (1802.40%)	NA [2]; (NA%)	0.30; (2621.06%)
Escape Week 0/Flare Baseline	Number Analyzed	72 participants	6 participants	14 participants
		NA [2]; (NA%)	30.77; (19.78%)	12.70; (98.45%)
Escape Week 2	Number Analyzed	71 participants	6 participants	15 participants
		18.27; (488.45%)	33.50; (21.17%)	15.43; (124.10%)
Escape Week 4	Number Analyzed	71 participants	6 participants	15 participants
		37.32; (151.18%)	32.94; (30.48%)	18.43; (79.93%)
Escape Week 12	Number Analyzed	69 participants	6 participants	15 participants
		23.89; (232.36%)	23.76; (65.42%)	19.14; (136.22%)
Escape Week 24	Number Analyzed	54 participants	3 participants	8 participants
		27.47; (45.31%)	NA [2]; (NA%)	19.23; (66.68%)
Escape Week 36	Number Analyzed	14 participants	3 participants	3 participants
		24.88; (77.53%)	NA [2]; (NA%)	NA [2]; (NA%)
Last Visit (Week 96)	Number Analyzed	66 participants	6 participants	14 participants
		24.64; (112.75%)	26.19; (54.74%)	18.59; (95.75%)
Withdrawal Escape Visit	Number Analyzed	4 participants	1 participants	0 participants
		4.71; (133329.3%)	NA [2]; (NA%)
Safety Follow-up	Number Analyzed	92 participants	92 participants	98 participants
		NA [2]; (NA%)	0.52; (1158.85%)	0.14; (772.54%)

[1]

Participants had no prior CZP treatment and thus no CZP levels at Baseline.

[2]

Values were below the level of detection.

32. Secondary Outcome

Title	Percentage of Participants With Positive Anti-certolizumab Pegol-antibody Levels in Plasma During the Study
Description	Treatment emergent ADAb status positive was defined as either baseline ADAb negative subjects having at least one ADAb confirmed positive sample post baseline or baseline ADAb positive subjects with at least one post baseline sample with >= minimum significant ratio (MSR) increase from baseline on CZP treatment. Once determined positive, the highest titer during Part A and Part B (including Escape and Safety Follow up) was used to categorize the subject. The primary purpose of the study was to evaluate treatment options for axSpA patients after being in sustained remission. Hence, one of the objectives was to evaluate the immunogenicity of these patients. The ADAb titer of the patients that did not reach sustained remission were therefore not analysed, and the Pharmacokinetic Set A as described in the protocol was removed from the SAP.
Time Frame	From Week 0 until the Safety Follow-up Visit (10 weeks after the last dose of study medication)

Outcome Measure Data

Analysis Population Description

The Pharmacokinetic Set B (PKSB) consisted of all study participants from the Safety Set Part B (SSB) who provided at least 1 PK sample during Part B.

Arm/Group Title	Placebo Double-Blind (PKSB)	Certolizumab Pegol 200 mg Q2W Double-Blind (PKSB)	Certolizumab Pegol 200 mg Q4W Double-Blind (PKSB)
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Pharmacokinetic Set B (PKSB).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the PKSB.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the PKSB.
Overall Number of Participants Analyzed	101	102	105
Measure Type: Number; Unit of Measure: percentage of participants
	100	96.1	100

33. Secondary Outcome

Title	Percentage of Participants With at Least One Adverse Event (AE) During Part A of the Study
Description	An AE was any untoward medical occurrence in a patient or clinical investigation study participant administered a pharmaceutical product that did not necessarily have a causal relationship with this treatment. An AE could therefore have been any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product.
Time Frame	From Screening Period (Week -5 to Week -1) until Week 48

Outcome Measure Data

Analysis Population Description

The Safety Set (SS) consisted of all study participants in the Enrolled Set (ES) who received at least 1 dose of investigational medicinal product (IMP).

Arm/Group Title	Certolizumab Pegol Open-Label (SS) Wk 0-48
Arm/Group Description:	Participants in this arm received certolizumab pegol (CZP) 400 mg subcutaneous (sc) on Weeks 0, 2 and 4, followed by 200 mg CZP sc every 2 weeks (Q2W) from Week 6 to Week 48 (Part A). Participants in sustained remission at Week 48 were eligible for randomization into Part B. Participants formed the Safety Set (SS).
Overall Number of Participants Analyzed	736
Measure Type: Number; Unit of Measure: percentage of participants
Screening Period (Week -5 to Week -1)	7.3
Open-Label Period (Week 0 to Week 48)	67.9

34. Secondary Outcome

Title	Percentage of Participants With at Least One Adverse Event (AE) During Part B of the Study
Description	An AE was any untoward medical occurrence in a patient or clinical investigation study participant administered a pharmaceutical product that did not necessarily have a causal relationship with this treatment. An AE could therefore have been any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. For subjects with flare in Part B and do escape to CZP full-dose therapy, only TEAEs with an onset date prior to the start date of escape CZP full-dose therapy were included.
Time Frame	From Week 0 until the Safety Follow-up Visit (10 weeks after the last dose of study medication)

Outcome Measure Data

Analysis Population Description

The Safety Set Part B (SSB) consisted of all study participants in the Randomized Set (RS) who received at least 1 dose of IMP in the Double-Blind Period of the study (Part B).

Arm/Group Title	Placebo Double-Blind (SSB) Wk 48-96	Certolizumab Pegol 200 mg Q2W Double-Blind (SSB) Wk 48-96	Certolizumab Pegol 200 mg Q4W Double-Blind (SSB) Wk 48-96
Arm/Group Description:	Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Safety Set Part B (SSB).	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the SSB.	Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the SSB.
Overall Number of Participants Analyzed	103	104	105
Measure Type: Number; Unit of Measure: percentage of participants
	54.4	57.7	61.0

35. Secondary Outcome

Title	Percentage of Participants With at Least One Adverse Event (AE) and Who Experienced a Flare During Part B of the Study
Description	An AE was any untoward medical occurrence in a patient or clinical investigation study participant administered a pharmaceutical product that did not necessarily have a causal relationship with this treatment. An AE could therefore have been any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. For subjects with flare in Part B and do escape to CZP full-dose therapy, only TEAEs with an onset date after or on the start date of escape CZP full-dose therapy were included.
Time Frame	From time of flare to Escape Week 12

Outcome Measure Data

Analysis Population Description

The Escape Therapy Set (ETS) consisted of all study participants from the Flared Set (FS) who received at least 1 dose of escape treatment.

Arm/Group Title	Placebo DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12	CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12	CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12
Arm/Group Description:	Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Escape Therapy Set (ETS).	Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the ETS.	Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the ETS.
Overall Number of Participants Analyzed	72	6	15
Measure Type: Number; Unit of Measure: percentage of participants
	51.4	83.3	46.7

Adverse Events

Time Frame	Adverse events were collected from Week 0 (Baseline) until the Safety Follow-Up Period (10 weeks after the last dose of study medication).
Adverse Event Reporting Description	TEAEs counts are for each study period: Open-Label (Wk0-48), Double-Blind (Wk48-96) and Escape (Wk0-12). During Escape (last 3 columns) all participants received CZP 200 mg Q2W at time of TEAEs, although they were coming from 3 arms of the double-blind phase. Participants randomized or who entered escape but received no treatment are not included.
Arm/Group Title	Certolizumab Pegol Open-Label (SS) Wk 0-48		Placebo Double-Blind (SSB) Wk 48-96		Certolizumab Pegol 200 mg Q2W Double-Blind (SSB) Wk 48-96		Certolizumab Pegol 200 mg Q4W Double-Blind (SSB) Wk 48-96		Placebo DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12		CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12		CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12
Arm/Group Description	Participants in this arm received certolizumab pegol (CZP) 400 mg subcutaneous (sc) on Weeks 0, 2 and 4, followed by 200 mg CZP sc every 2 weeks (Q2W) from Week 6 to Week 48 (Part A). Participants in sustained remission at Week 48 were eligible for randomization into Part B. Participants formed the Safety Set (SS).		Participants in this arm received Placebo subcutaneous (sc) every 2 weeks from Week 48 onwards. Participants formed the Safety Set Part B (SSB).		Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 2 weeks (Q2W) from Week 48 onwards. Participants formed the SSB.		Participants in this arm received certolizumab pegol (CZP) 200 mg subcutaneous (sc) every 4 weeks (Q4W) from Week 48 onwards. At visits where CZP was not received, subjects received one injection of Placebo to maintain the study blind. Participants formed the SSB.		Participants randomized to Placebo who met flare criteria received CZP 400 mg subcutaneous (sc) every 2 weeks (Q2W) for the first 3 visits after flare has been confirmed. After that, CZP 200 mg was given every 2 weeks in open-label fashion. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the Escape Therapy Set (ETS).		Participants randomized to CZP 200 mg Q2W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the ETS.		Participants randomized to CZP 200 mg Q4W who meet flare criteria received CZP 200 mg subcutaneous (sc) every 2 weeks (Q2W) for all visits after flare has been confirmed. At the first 3 visits after flare has been confirmed, participants received one injection of 200 mg CZP and one injection of Placebo to maintain the study blind. The duration was from starting escape treatment after flare until Week 96 with a minimum of 12 weeks. Participants formed the ETS.
All-Cause Mortality
	Certolizumab Pegol Open-Label (SS) Wk 0-48		Placebo Double-Blind (SSB) Wk 48-96		Certolizumab Pegol 200 mg Q2W Double-Blind (SSB) Wk 48-96		Certolizumab Pegol 200 mg Q4W Double-Blind (SSB) Wk 48-96		Placebo DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12		CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12		CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12
	Affected / at Risk (%)		Affected / at Risk (%)		Affected / at Risk (%)		Affected / at Risk (%)		Affected / at Risk (%)		Affected / at Risk (%)		Affected / at Risk (%)
Total	0/736 (0.00%)		0/103 (0.00%)		0/104 (0.00%)		0/105 (0.00%)		0/72 (0.00%)		0/6 (0.00%)		0/15 (0.00%)
Serious Adverse Events
	Certolizumab Pegol Open-Label (SS) Wk 0-48		Placebo Double-Blind (SSB) Wk 48-96		Certolizumab Pegol 200 mg Q2W Double-Blind (SSB) Wk 48-96		Certolizumab Pegol 200 mg Q4W Double-Blind (SSB) Wk 48-96		Placebo DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12		CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12		CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	44/736 (5.98%)		0/103 (0.00%)		5/104 (4.81%)		0/105 (0.00%)		0/72 (0.00%)		1/6 (16.67%)		0/15 (0.00%)
Blood and lymphatic system disorders
Lymphadenopathy * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Cardiac disorders
Tachycardia * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Eye disorders
Retinal vein occlusion * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Gastrointestinal disorders
Pancreatitis acute * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	1/104 (0.96%)	1	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Colitis ulcerative * 1	2/736 (0.27%)	3	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Dental caries * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Glossitis * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Crohn's disease * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	1/104 (0.96%)	1	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Intestinal obstruction * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	1/104 (0.96%)	1	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Irritable bowel syndrome * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	1/6 (16.67%)	1	0/15 (0.00%)	0
Immune system disorders
Drug hypersensitivity * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Infections and infestations
Appendicitis * 1	2/736 (0.27%)	2	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Perirectal abscess * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Meningitis aseptic * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Pulpitis dental * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Hepatitis E * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Abscess limb * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Wound infection * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Pneumonia * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Pneumonia mycoplasmal * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Pulmonary tuberculosis * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Tuberculous pleurisy * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Peritonsillar abscess * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Pyelonephritis * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Anal abscess * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	1/104 (0.96%)	1	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Latent tuberculosis * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	1/104 (0.96%)	1	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Injury, poisoning and procedural complications
Meniscus injury * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Foot fracture * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Epicondylitis * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Ligament rupture * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Tendon rupture * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Limb injury * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Investigations
False positive tuberculosis test * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Musculoskeletal and connective tissue disorders
Intervertebral disc protrusion * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Axial spondyloarthritis * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Nervous system disorders
Migraine * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Optic neuritis * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Pregnancy, puerperium and perinatal conditions
Abortion spontaneous * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Pregnancy on contraceptive * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Psychiatric disorders
Depression * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Schizophrenia * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Renal and urinary disorders
Ureterolithiasis * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Reproductive system and breast disorders
Endometrial hyperplasia * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Respiratory, thoracic and mediastinal disorders
Chronic obstructive pulmonary disease * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Nasal septum deviation * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Skin and subcutaneous tissue disorders
Dermatitis atopic * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Dyshidrotic eczema * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Pustular psoriasis * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Urticaria * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
1 Term from vocabulary, MedDRA19.0; * Indicates events were collected by non-systematic assessment
Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events	5%
	Certolizumab Pegol Open-Label (SS) Wk 0-48		Placebo Double-Blind (SSB) Wk 48-96		Certolizumab Pegol 200 mg Q2W Double-Blind (SSB) Wk 48-96		Certolizumab Pegol 200 mg Q4W Double-Blind (SSB) Wk 48-96		Placebo DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12		CZP 200 mg Q2W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12		CZP 200 mg Q4W DB/CZP 200 mg Q2W Escape (ETS) Escape Wk 0->=12
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	188/736 (25.54%)		25/103 (24.27%)		31/104 (29.81%)		26/105 (24.76%)		20/72 (27.78%)		5/6 (83.33%)		7/15 (46.67%)
Blood and lymphatic system disorders
Iron deficiency anaemia * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	1/15 (6.67%)	1
Eye disorders
Iritis * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	1/15 (6.67%)	1
Gastrointestinal disorders
Irritable bowel syndrome * 1	2/736 (0.27%)	2	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	1/6 (16.67%)	1	0/15 (0.00%)	0
General disorders
Influenza like illness * 1	8/736 (1.09%)	9	1/103 (0.97%)	1	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	1/6 (16.67%)	1	0/15 (0.00%)	0
Immune system disorders
Drug hypersensitivity * 1	4/736 (0.54%)	4	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	1/6 (16.67%)	2	0/15 (0.00%)	0
Infections and infestations
Nasopharyngitis * 1	117/736 (15.90%)	156	8/103 (7.77%)	8	12/104 (11.54%)	17	13/105 (12.38%)	18	8/72 (11.11%)	9	2/6 (33.33%)	2	1/15 (6.67%)	1
Upper respiratory tract infection * 1	63/736 (8.56%)	88	10/103 (9.71%)	12	12/104 (11.54%)	14	11/105 (10.48%)	12	5/72 (6.94%)	7	1/6 (16.67%)	1	1/15 (6.67%)	1
Pharyngitis * 1	22/736 (2.99%)	24	3/103 (2.91%)	3	2/104 (1.92%)	2	6/105 (5.71%)	6	2/72 (2.78%)	2	0/6 (0.00%)	0	1/15 (6.67%)	1
Oral herpes * 1	13/736 (1.77%)	21	2/103 (1.94%)	3	1/104 (0.96%)	3	2/105 (1.90%)	2	1/72 (1.39%)	1	1/6 (16.67%)	3	0/15 (0.00%)	0
Hordeolum * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	1/6 (16.67%)	1	0/15 (0.00%)	0
Influenza * 1	9/736 (1.22%)	9	1/103 (0.97%)	1	3/104 (2.88%)	3	1/105 (0.95%)	1	2/72 (2.78%)	3	1/6 (16.67%)	1	0/15 (0.00%)	0
Bronchitis * 1	24/736 (3.26%)	25	3/103 (2.91%)	3	0/104 (0.00%)	0	3/105 (2.86%)	3	1/72 (1.39%)	1	0/6 (0.00%)	0	1/15 (6.67%)	1
Conjunctivitis * 1	6/736 (0.82%)	6	1/103 (0.97%)	1	0/104 (0.00%)	0	1/105 (0.95%)	1	0/72 (0.00%)	0	0/6 (0.00%)	0	1/15 (6.67%)	1
Furuncle * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	1/15 (6.67%)	1
Laryngitis * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	0/104 (0.00%)	0	1/105 (0.95%)	2	0/72 (0.00%)	0	0/6 (0.00%)	0	1/15 (6.67%)	1
Latent tuberculosis * 1	5/736 (0.68%)	5	0/103 (0.00%)	0	3/104 (2.88%)	3	2/105 (1.90%)	2	1/72 (1.39%)	1	0/6 (0.00%)	0	1/15 (6.67%)	1
Sinusitis * 1	12/736 (1.63%)	12	1/103 (0.97%)	1	0/104 (0.00%)	0	2/105 (1.90%)	2	0/72 (0.00%)	0	0/6 (0.00%)	0	1/15 (6.67%)	1
Investigations
Antinuclear antibody increased * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	1/6 (16.67%)	1	0/15 (0.00%)	0
Musculoskeletal and connective tissue disorders
Axial spondyloarthritis * 1	8/736 (1.09%)	8	8/103 (7.77%)	8	6/104 (5.77%)	6	1/105 (0.95%)	1	0/72 (0.00%)	0	0/6 (0.00%)	0	0/15 (0.00%)	0
Joint stiffness * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	0/6 (0.00%)	0	1/15 (6.67%)	1
Nervous system disorders
Cervicogenic vertigo * 1	0/736 (0.00%)	0	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	1/6 (16.67%)	1	0/15 (0.00%)	0
Sciatica * 1	1/736 (0.14%)	1	0/103 (0.00%)	0	0/104 (0.00%)	0	0/105 (0.00%)	0	0/72 (0.00%)	0	1/6 (16.67%)	1	0/15 (0.00%)	0
Respiratory, thoracic and mediastinal disorders
Oropharyngeal pain * 1	12/736 (1.63%)	14	0/103 (0.00%)	0	3/104 (2.88%)	3	2/105 (1.90%)	2	0/72 (0.00%)	0	0/6 (0.00%)	0	1/15 (6.67%)	1
1 Term from vocabulary, MedDRA19.0; * Indicates events were collected by non-systematic assessment

Limitations and Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There IS an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.

Results Point of Contact

• Name/Title: UCB
• Organization: Cares
• Phone: +1844 599 ext 2273
• EMail: UCBCares@ucb.com

Publications:

Landewe RB, van der Heijde D, Dougados M, Baraliakos X, Van den Bosch FE, Gaffney K, Bauer L, Hoepken B, Davies OR, de Peyrecave N, Thomas K, Gensler LS. Maintenance of clinical remission in early axial spondyloarthritis following certolizumab pegol dose reduction. Ann Rheum Dis. 2020 Jul;79(7):920-928. doi: 10.1136/annrheumdis-2019-216839. Epub 2020 May 7. Erratum In: Ann Rheum Dis. 2020 Sep;79(9):e120.

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

Landewe R, van der Heijde D, Dougados M, Baraliakos X, Van den Bosch F, Gaffney K, Bauer L, Hoepken B, de Peyrecave N, Thomas K, Gensler LS. Induction of Sustained Clinical Remission in Early Axial Spondyloarthritis Following Certolizumab Pegol Treatment: 48-Week Outcomes from C-OPTIMISE. Rheumatol Ther. 2020 Sep;7(3):581-599. doi: 10.1007/s40744-020-00214-7. Epub 2020 Jun 11.

• Responsible Party: UCB Pharma ( UCB BIOSCIENCES GmbH )
• ClinicalTrials.gov Identifier: NCT02505542
• Other Study ID Numbers: AS0005; 2015-000339-34 ( EudraCT Number )
• First Submitted: July 16, 2015
• First Posted: July 22, 2015
• Results First Submitted: February 26, 2020
• Results First Posted: April 21, 2020
• Last Update Posted: December 17, 2020