(010) Drug Survival of Baricitinib in Treatment-Naïve Patients with Rheumatoid Arthritis (RA): a population-based study

Background: Drug survival can be considered as the overall effectiveness of drugs that reflect patients' adherence to a specific treatment. Clinical trials had demonstrated the drug survival of baricitinib for treating RA. However, there was limited evidence comparing drug survival between baricitinib and b-DMARDs (biological disease-modifying anti-rheumatic drugs) or other ts-DMARDs (target-synthetic DMARDs).

Objectives: To compare the drug survival of baricitinib with tofacitinib and b-DMARDs among patients with rheumatoid arthritis, by evaluating the risk of treatment change.

Methods: This retrospective cohort study included patients newly prescribed (with a one-year washout period) ts-DMARDs or b-DMARDs from the National Health Insurance Research Database between 2010 and 2020. Patients with ulcerative colitis or Crohn’s disease, or those without sex or birth information, were excluded. The outcome was treatment change, defined as discontinuation (no refill of prescription for more than 90 days) or switching to another drug. We followed up patients for 3 years, or until the occurrence of treatment change, death, and the end of the database (December 31, 2021), whichever came first. We performed Cox proportional hazards models to compare the risk of treatment change between groups, with adjustments for age, sex, income level, comorbidities, and co-medications. A series of sensitivity analyses were conducted with various definitions of discontinuation (60, 180, and 365 days) and subgroups (sex, age, index year, with and without methotrexate).

Results: We included 18,730 patients (327 baricitinib users) with a mean age of 56 (SD: 13.2) and 82.2% female. We found baricitinib was associated with a lower risk of treatment change compared to golimumab (HR=0.74; 95% CI, 0.55-0.99) and adalimumab (HR=0.71; 95% CI, 0.53-0.95), but with similar risk when compared to tofacitinib (HR=0.99; 95% CI: 0.74-1.33). These results were consistent across a series of sensitivity analyses.

Conclusions: The results suggested that baricitinib had better drug survival than golimumab and adalimumab but no significant difference from tofacitinib. These findings provided a reference for treatment strategies in real-world practice.