RESUMEN
BACKGROUND AND METHODS: The efficacy and safety of etoricoxib 60 mg/day in patients with established chronic low back pain (CLBP) were compared with those of diclofenac 150 mg/day in a 4-week, multicentre, randomized, double-blind, parallel-group trial. Four hundred and forty-six adult patients with CLBP (Quebec Task Force on Spinal Disorders Class 1 or 2) and with worsening pain upon discontinuation of pre-study analgesic medication were enrolled in the study. The study primary efficacy endpoint was change from baseline in Low Back Pain Intensity Scale (LBP-IS) score over the 4-week treatment period. Secondary and other efficacy endpoints included: changes in Roland and Morris Disability Questionnaire (RMDQ), Patient Global Assessment of Response to Therapy (PGART) and Low Back Pain Bothersomeness Scale (LBP-BS) scores. Early efficacy was assessed using PGART and LBP-IS scores 4 h after the first dose on the mornings of Days 1, 2 and 3. The overall safety and tolerability of etoricoxib 60 mg/day during 4 weeks of treatment were also assessed. RESULTS: The least-squares mean time-weighted change from baseline LBP-IS score over 4 weeks was -32.94 mm (95% CI -36.25, -29.63) for etoricoxib, indicating substantial efficacy in relief of pain. The treatment difference for the primary outcome was 2.51 mm (95% CI -1.50, 6.51), fulfilling the prespecified equivalence criterion of 95% confidence interval wholly within +/- 10 mm. Etoricoxib improved all secondary and other efficacy outcomes. There were no statistically significant between-group differences in the proportion of patients with one or more clinical adverse events (AEs) (etoricoxib 35%, diclofenac 39%), or the proportion of patients who discontinued due to AEs (etoricoxib 7%, diclofenac 5%). CONCLUSIONS: The results of this study confirm that, for adult patients with CLBP, etoricoxib 60 mg once daily over 4 weeks is effective for relief of pain and improvement of physical function and comparable to high-dose diclofenac 150 mg daily.