A comparison of the therapeutic efficacy and tolerability of etoricoxib and diclofenac in patients with osteoarthritis

Objective: To evaluate and compare the efficacy and tolerability of etoricoxib and diclofenac in patients with osteoarthritis of the knee or hip. Methods: In this 6-week double-blind, active comparator controlled, parallel-group study eligible osteoarthritis patients were randomised to receive either etoricoxib 60 mg once daily (n = 256) or diclofenac 50 mg three times daily (n = 260). The primary study endpoint was the Western Ontario McMaster osteoarthritis index (WOMAC) pain subscale. Other endpoints included were the WOMAC stiffness and physical function subscales, and the Patient's Global Assessment of Besponse to Therapy (PGART) questionnaire. Early efficacy was evaluated using WOMAC first question (pain walking on a flat surface) and PGART 4 h after the morning dose of each drug on days 1 and 2. Rescue medication (paracetamol) used was also recorded. The study was designed to show comparable efficacy between etoricoxib 60 mg once daily and diclofenac 50 mg three times daily with respect to the primary endpoint and was conducted outside the United States at 67 centres in 29 countries. Results: Etoricoxib (60 mg once daily) was comparable in efficacy to diclofenac (150 mg daily) on all the above parameters. The one exception was in the assessment of early efficacy where etoricoxib demonstrated significantly greater benefit within 4 h of taking the first dose on the first day of therapy (p = 0.007) as evaluated by the percentage of patients with good or excellent (PGART) responses. The treatment effects of both drugs were similar by the time day 2 was reached and were sustained throughout the 6 weeks of therapy. Both treatments were generally well tolerated. Conclusions: Etoricoxib is clinically effective in the therapy of osteoarthritis providing a magnitude of effect comparable to that of the maximum recommended daily dose of diclofenac. The onset of clinical benefit with etoricoxib on day one is more rapid than that of diclofenac. Both drugs were generally well tolerated.