Assessment of long-term safety and efficacy of etanercept in a 5-year extension study in patients with rheumatoid arthritis.

OBJECTIVES: To evaluate long-term safety and efficacy of etanercept (ETN) in patients with rheumatoid arthritis (RA) without concomitant disease-modifying antirheumatic drug therapy.
METHODS: A total of 549 patients enrolled in this 5-year, open-label extension after completing 1 of 2 randomised controlled studies; all patients received ETN 25 mg twice weekly during the extension. Safety assessments included physical exams, adverse events (AEs), vital signs, laboratory tests, and autoantibody evaluations. Key efficacy endpoints included numbers of responders achieving the American College of Rheumatology (ACR) criteria, low disease activity scores, and disease remission.
RESULTS: Three hundred and eight (56%) patients completed the 5-year extension study. Total ETN exposure, including that received during the double-blind studies was 2212 patient-years. Withdrawals for efficacy- and safety-related reasons were 12% and 19%, respectively. The most common AE was upper respiratory infection (44%). Rates of serious infections decreased over the 5-year period; one case of suspected tuberculosis was reported. Rates of malignancies remained generally consistent during the 5-year period. There were no reports of demyelinating disease, serious blood dyscrasias, or opportunistic infections. The relationship between autoantibody titres and clinical events was not statistically significant. Less than 5% of patients tested positive for anti-etanercept antibodies and all antibodies were non-neutralising. After 5 years, ACR 20, 50, and 70 response rates were 78%, 51%, and 32%, respectively; the mean percentage of patients achieving low disease activity score (DAS ≤ 2.4) and remission (DAS ≤ 1.6) were 44% and 20%, respectively.
CONCLUSIONS: ETN maintained a favourable safety profile and consistent efficacy throughout the 5-year study duration.