Patients having completed the week 34 assessment in the C87077 (NCT00580840) study or having met the pre-defined criteria for flare (defined as patients that have randomized at Week 18 and experienced at 2 consecutive visits between Week 18 and Week 34 inclusive an equal to Baseline (W0) or worst swollen and tender joints counts), will be given the option to enroll in C87084 and receive certolizumab pegol \[400 mg at Entry, Week 2, and Week 4 followed by 200 mg every two weeks (Q2W)\] in combination with MTX until the drug is commercially available for the indication of Rheumatoid Arthritis (RA) in the patient's country or region or until further notice from UCB.
All patients will continue their MTX treatment at the same stable dose as during the C87077 (NCT00580840) study, unless there is a need to reduce the dose for reasons for toxicity.