Single-Arm Study of Etanercept in Adult Patients with Moderate to Severe Rheumatoid Arthritis Who Failed Adalimumab Treatment

INTRODUCTION: To evaluate the efficacy and safety of etanercept treatment in adult patients with moderate to severe rheumatoid arthritis (RA) who failed to respond (primary failure) or lost a satisfactory response (secondary failure) to adalimumab. METHODS: All patients discontinued prior adalimumab treatment and continued methotrexate with etanercept 50 mg once weekly for 24 weeks. The primary study endpoint was American College of Rheumatology 20% improvement criteria (ACR20) at week 12. RESULTS: Eighty-five patients (mean age 56.6 years; female 80.0%) were evaluated for safety and 84 for efficacy. Thirty (35.7%) patients achieved ACR20 at week 12; the lower bound of the 95% confidence interval (CI; 25.6, 46.9) was greater than the prespecified goal of 24% based on previous research. Improvements from baseline in clinical outcomes and patient-reported outcomes were observed at each study visit. In planned subgroup analyses, patients with anti-adalimumab antibodies and secondary adalimumab failure had the highest ACR20 response to etanercept at week 12 (11/17 patients; 64.7%). Among the patients with secondary adalimumab failure, those with anti-adalimumab antibodies were fivefold more likely to have an ACR20 response to etanercept than those without anti-adalimumab antibodies (odds ratio 5.2; 95% CI 2.0, 13.5; P < 0.001). Adverse events were reported for 62 (72.9%) patients and were consistent with previous studies of etanercept. Most adverse events were mild or moderate in severity. CONCLUSION: Switching to etanercept is a therapeutic option in patients with RA who fail adalimumab treatment. The presence of anti-adalimumab antibodies may provide additional support for switching to etanercept, particularly in patients with secondary adalimumab failure. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT01927757.