Real-world effectiveness of select biologic and DMARD monotherapy and combination therapy in the treatment of rheumatoid arthritis: results from the RADIUS observational registry

Objective: To evaluate the effectiveness of select biologics, methotrexate (MTX), and other disease-modifying anti-rheumatic drugs (DMARDs) in the management of adult rheumatoid arthritis (RA) in routine clinical practice. Research design and methods: RADIUS (Rheumatoid Arthritis DMARD Intervention and Utilization Study) comprises two prospective, 5-year, observational registries of over 10000 patients. Over 4600 patients who initiated MTX or a biologic regimen (etanercept [ETN], infliximab [INF], ETN + MTX, and INF + MTX) and who had at least one on-regimen, follow-up evaluation, were included in this analysis. Adalimumab was not included because it had not yet received FDA approval at RADIUS initiation. Other common DMARD regimens (N = 762) were also compared with MTX. Patients who initiated less commonly used regimens, such as anakinra or cyclosporine, and those who did not have at least one on-regimen, follow-up evaluation, were not eligible for this analysis. Because ESR/CRP measurements were often not available, a modified ACR20 response (mACR20), defined as three out of four response criteria excluding ESR/CRP, was used to assess response at 12 months. Logistic regression analysis was performed to control for baseline covariates that may affect outcomes. Main outcome measures: The primary endpoint was the proportion of patients who achieved a mACR20 response at 12 months post-RADIUS entry. Results: After adjusting for baseline covariates, patients receiving either ETN + MTX or ETN monotherapy were more likely to achieve a mACR20 response at 12 months than patients receiving MTX alone (odds ratio [OR] 1.29, 95% confidence interval [CI] 1.09-1.52; p < 0.01 and OR 1.23, 95% CI 1.02-1.47; p < 0.05, respectively). Conversely, patients treated with MTX + leflunomide (LEF) were less likely to achieve a mACR20 response than those receiving MTX alone (OR 0.68, 95% CI 0.48-0.96; p < 0.05). Significant differences were not observed between patients receiving MTX alone and either INF + MTX, MTX + hydroxychloroquine, MTX + hydroxychloroquine + sulfasalazine, INF monotherapy, or LEF monotherapy. Conclusion: These data from routine rheumatology clinical practice settings highlight the effectiveness of common biologic and DMARD therapies, and provide additional data beyond those of randomized, controlled trials.