Etoricoxib is a cyclooxygenase-2 (COX-2) selective inhibitor effective in the treatment of rheumatoid arthritis. An initial 12-week treatment study found that etoricoxib (90 mg once daily) was more effective than naproxen (500 mg twice daily) or placebo in treating rheumatoid arthritis. The present two-part extension of that study was performed to monitor tolerability and examine long-term efficacy of etoricoxib 90 mg or 120 mg compared with naproxen.
Patients completing the initial 12-week study and those discontinuing due to lack of efficacy, were eligible for the Extension Study Part I (12-52 weeks) and assigned (2:1:2 ratio) to receive etoricoxib (90 mg or 120 mg daily) or naproxen (500 mg twice daily); these patients remained on the same therapy for Extension Study Part II (52-121 weeks). Primary outcome measures included investigator and patient assessment of disease activity, and tender and swollen joint counts.
Of 816 patients enrolled in the initial 12-week trial, 717 continued into the Extension Study Part I; 505 patients completed and 390 entered the Extension Study Part II, with 283 patients completing 121 weeks. Patients receiving etoricoxib (90 mg) or naproxen throughout the study experienced sustained efficacy in all outcomes, as did patients transitioning to etoricoxib (120 mg) following the initial 12-week trial. Patients transitioning from placebo to etoricoxib (90 mg) experienced rapid, sustained improvements in all outcome measures.
In conclusion, etoricoxib provided sustained efficacy throughout the 121-week study, with efficacy comparable to naproxen.