OBJECTIVE: To evaluate the effect of adalimumab treatment on clinical remission and/or minimal disease activity (MDA) in 6,610 patients with active rheumatoid arthritis (RA) who were enrolled in the Research in Active RA trial, a multinational, open-label, 12-week study with an optional extension period. METHODS: Clinical remission was defined as a Disease Activity Score in 28 joints (DAS28)<2.6, Simplified Disease Activity Index (SDAI) score<or=3.3, or Clinical Disease Activity Index (CDAI) score<or=2.8. MDA required absence of tender and swollen joints plus erythrocyte sedimentation rate (ESR)<or=10 mm/hour; DAS28 score<or=2.85; or achievement of 5 of 7 core criteria for pain, swollen/tender joints, physical function, physician/patient global assessment, and ESR. Time to and time in remission/MDA and response predictors were analyzed using Kaplan-Meier estimates and Cox proportional hazards regression analysis, respectively. RESULTS: A total of 38%, 24%, and 27% of patients achieved remission defined as DAS28<2.6, SDAI<or=3.3, and CDAI<or=2.8, respectively. MDA was observed in 45% of patients by DAS28<or=2.85, in 43% by the core set of criteria, and in 13% by absence of tender/swollen joints plus ESR<or=10 mm/hour. Median times in continuous remission and MDA were 3.4 and 4.4 months, respectively. Predictors for remission (DAS28<2.6) and MDA (DAS28<or=2.85) were male sex; younger age; concomitant disease-modifying antirheumatic drug use; lower baseline DAS28, CRP concentration, and Health Assessment Questionnaire disease index score; <or=1 comorbidity; and tumor necrosis factor antagonist naivety. CONCLUSION: During adalimumab treatment, 25% of patients experienced clinical remission and nearly half achieved MDA. To our knowledge, this analysis represents the largest prospective clinical trial data set to be assessed using Outcome Measures in Rheumatology Clinical Trials MDA criteria.