 Participants were to be stratified by prior exposure to infliximab andor other anti-TNF agents, and randomized in a 1:1 ratio to receive ADA or placebo by subcutaneous injection. Participants assigned to the ADA treatment arm were to receive an induction dose of 160 mg at Week 0 and 80 mg at Week 2, and 40 mg every other week eow starting at Week 4. Participants assigned to the placebo treatment arm were to receive matching placebo during the same period of time. At or after Week 10, participants who met the criteria for inadequate response could be switched to open-label OL ADA 40 mg eow beginning at Week 12. Inadequate response was defined as: 