Comparative Effectiveness, Time to Discontinuation, and Patient-Reported Outcomes with Baricitinib in Rheumatoid Arthritis: 2-Year Data from the Multinational, Prospective Observational RA-BE-REAL Study in European Patients

INTRODUCTION: RA-BE-REAL is a 3-year, multinational, prospective, observational study of adult patients with rheumatoid arthritis (RA) evaluating time to discontinuation of initial RA treatment along with patient baseline characteristics. This study’s primary objective was to assess the time to discontinuation of initial baricitinib, any other targeted synthetic disease-modifying anti-rheumatic drug (tsDMARD), or any biologic disease-modifying anti-rheumatic drug (bDMARD) treatment for all causes (excluding sustained clinical response) over 24 months in a European population. METHODS: Patients initiated treatment with baricitinib (cohort A) or any bDMARD or tsDMARD (cohort B) for the first time. This study’s primary objective was to assess the time to discontinuation of initial baricitinib, any other targeted synthetic disease-modifying anti-rheumatic drug (tsDMARD), or any biologic disease-modifying anti-rheumatic drug (bDMARD) treatment for all causes (excluding sustained clinical response) over 24 months in a European population. Comparative effectiveness analyses, over 24 months, included time to treatment discontinuation for all causes (excluding sustained clinical response), percentage of patients achieving Clinical Disease Activity Index (CDAI) remission or low disease activity (LDA), as well as mean changes from baseline for CDAI, pain visual analogue scale, and the Health Assessment Questionnaire-Disability Index (HAQ-DI). For this European subpopulation, comparative analyses were performed using a frequentist model averaging (FMA) framework based on a data-driven machine learning causal inference approach to compare time to discontinuation, effectiveness, rates of remission or LDA, and patient-reported outcomes over 24 months comparing baricitinib with TNFi, as well as non-TNFi and tsDMARD grouped as other mechanism of action (OMA) drugs. RESULTS: In the European sample of RA-BE-REAL, patients with RA treated with baricitinib experienced fewer discontinuations in comparison to those treated with tumour necrosis factor inhibitors or OMA. Overall, patients naïve to b/tsDMARDs achieved a higher rate of LDA and remission compared with experienced patients. A significantly greater proportion of patients treated with baricitinib achieved LDA compared with b/tsDMARDs. CONCLUSION: This real-world data can better inform clinicians about baricitinib effectiveness and drug survival when prescribing treatment for patients with RA across different subpopulations. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40744-023-00597-3.