A follow-on Safety Study of CDP870 in Subjects With Crohn's Disease (CD) Who Have Completed a 26-week Double Blind Study CDP870-031 [NCT00152490] or CDP870-032 [NCT00152425]

An AE is defined as any untoward medical occurrence in a subject or clinical investigation subject administered a pharmaceutical product and which does not necessarily have a causal relationship with this treatment.

Time frame: Up to 84 months from Study Entry (Week 0) to the Study End (Week 364) and the Safety Follow-up (Week 374)

Population: All 595 subjects in the Safety Population are included in the analysis of this outcome measure. Safety Population includes all enrolled subjects who received at least one injection of study treatment in feeder study C87031 \[NCT00152490\] or C87032 \[NCT00152425\].

An SAE is defined as any untoward medical occurrence that occurs at any dose which results in death, is life threatening, requires hospitalization, results in persistent/significant disability/incapacity, is an infection that requires parenteral antibiotics, is a congenital anomaly/birth defect, or is an important medical event.

Time frame: Up to 84 months from Study Entry (Week 0) to the Study End (Week 364) and the Safety Follow-up (Week 374)

Population: All 595 subjects in the Safety Population are included in the analysis of this outcome measure. Safety Population includes all enrolled subjects who received at least one injection of study treatment in feeder study C87031 \[NCT00152490\] or C87032 \[NCT00152425\].

Time frame: Study Completion Visit (Week 364) / (Early) Withdrawal Visit

Population: Of the 594 subjects in the Intention-To-Treat (ITT) Population, 593 subjects are included in the analysis of this outcome measure. ITT Population includes all subjects of the Safety Population who provide at least one efficacy measurement after Week 0 of this study.

Time frame: Week 258 / (Early) Withdrawal Visit, if it is earlier than Week 258

Population: Of the 594 subjects in the Intention-To-Treat (ITT) Population, 567 subjects are included in the analysis of this outcome measure. ITT Population includes all subjects of the Safety Population who provide at least one efficacy measurement after Week 0 of this study.

HBI remission is defined as total HBI score of 4 points or less. HBI score consists of clinical parameters of general well-being (0 to 4), abdominal pain (0 to 3), number of liquid stools per day, abdominal mass (0 to 3), and complications (8 items, score 1 per item) lower scores indicating better well being. The first three parameters are scored for the previous day.

Time frame: Study Completion Visit (Week 364) / (Early) Withdrawal Visit

Population: Of the 594 subjects in the Intention-To-Treat (ITT) Population, 592 subjects are included in the analysis of this outcome measure. ITT Population includes all subjects of the Safety Population who provide at least one efficacy measurement after Week 0 of this study.

Response is defined as decrease in total Harvey Bradshaw Index (HBI) score of 3 or more points. HBI score consists of clinical parameters of general well-being (0 to 4), abdominal pain (0 to 3), number of liquid stools per day, abdominal mass (0 to 3), and complications (8 items, score 1 per item) lower scores indicating better well-being. The first three parameters are scored for the previous day.

Time frame: From Week 0 of study CDP870-031 [NCT00152490] or CDP870-032 [NCT00152425] to Study Completion Visit (Week 364) of this study (up to 90 months) or (Early) Withdrawal Visit

Population: All 594 subjects in the Intention-To-Treat (ITT) Population are included in the analysis of this outcome measure. ITT Population includes all subjects of the Safety Population who provide at least one efficacy measurement after Week 0 of this study.

Subjects are counted as antibody positive to Certolizumab Pegol if they have at least one positive result from Week 0 in one of the previous studies CDP870-031 \[NCT00152490\] or CDP870-032 \[NCT00152425\] to the Last Visit in this study. A positive result is defined as Anti-CZP antibody levels \> 2.4 units/mL.

Time frame: From Week 0 of study CDP870-031 [NCT00152490] or CDP870-032 [NCT00152425] to Study Completion Visit (Week 364) of CDP870-033 (up to 90 months)

Population: Of the 595 subjects in the Safety Population, 593 subjects are included in the analysis of this outcome measure. Safety Population includes all enrolled subjects who received at least one injection of study treatment in feeder study C87031 \[NCT00152490\] or C87032 \[NCT00152425\].

Plasma samples for determination of Certolizumab Pegol were taken prior to Certolizumab Pegol administration.

Time frame: Study Completion Visit (Week 364) / (Early) Withdrawal Visit

Population: Of the 595 subjects in the Safety Population, 590 subjects are included in the analysis of this outcome measure. Safety Population includes all enrolled subjects who received at least one injection of study treatment in feeder study C87031 \[NCT00152490\] or C87032 \[NCT00152425\].