Efficacy of Rofecoxib, Celecoxib, and Acetaminophen in Osteoarthritis of the Knee: a Randomized Trial

Context: Osteoarthritis (OA) is often treated with nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, or specific inhibitors of cyclooxygenase 2 (COX-2).

Objective: To assess the relative therapeutic efficacy of rofecoxib, celecoxib, and acetaminophen in adults with OA.

Design And Setting: Randomized, parallel-group, double-blind trial, conducted from June 1999 to February 2000, in 29 clinical centers in the United States.

Patients: Three hundred eighty-two patients aged at least 40 years who had OA of the knee that was previously treated with NSAIDs or acetaminophen.

Interventions: Patients were randomly assigned to receive rofecoxib, 12.5 mg/d (n = 96); rofecoxib, 25 mg/d (n = 95); celecoxib, 200 mg/d (n = 97); or acetaminophen, 4000 mg/d (n = 94) for 6 weeks.

Main Outcome Measures: Assessments over days 1 to 6 and over 6 weeks included pain on walking, night pain, pain at rest, and morning stiffness as measured on a Western Ontario McMaster Universities Osteoarthritis Index (100-mm visual analog scale [VAS]) and global response to therapy compared among 4 treatment groups.

Results: 79% of patients completed the study. More patients treated with acetaminophen discontinued early due to lack of efficacy than patients treated with COX-2 inhibitors (31% vs 18%-19%). Efficacy assessed in the first 6 days of therapy showed greatest response to rofecoxib, 25 mg/d, followed by rofecoxib, 12.5 mg/d, celecoxib, and acetaminophen, respectively, in terms of relief of pain on walking (-32.2, - 29.0, - 26.4, and -20.6 mm change on the VAS; P</=.04 for all others vs acetaminophen; P =.05 for 25-mg rofecoxib vs celecoxib), rest pain (-21.8, - 18.6, - 15.5, and - 12.5 mm; P</=.02 for either dose of rofecoxib vs acetaminophen and P =.02 for rofecoxib, 25 mg/d, vs celecoxib), night pain (-25.2, - 22.0, - 18.7, and - 18.8 mm; P =.04 for rofecoxib, 25 mg/d, vs both acetaminophen and celecoxib), and morning stiffness (-30.4, - 28.4, - 25.7, and - 20.9 mm; P</=.02 for either dose of rofecoxib vs acetaminophen). Over 6 weeks, rofecoxib, 25 mg/d, provided greatest response for night pain (P<.002 vs celecoxib and P =.006 vs acetaminophen and P =.02 vs rofecoxib, 12.5 mg/d), composite pain subscale (P</=.03 vs all other treatments), stiffness subscale (P</=.04 vs celecoxib and acetaminophen), and physical function subscale (P =.001 vs acetaminophen). Global responses over 6 weeks showed a similar pattern (good or excellent response at week 6: 60%, 56%, 46%, and 39%, respectively; P</=.03 for rofecoxib, 25 mg/d, vs celecoxib and acetaminophen; P =.02 for rofecoxib, 12.5 mg/d, vs acetaminophen). All treatments were generally safe and well tolerated.

Conclusion: Rofecoxib, 25 mg/d, provided efficacy advantages over acetaminophen, 4000 mg/d, celecoxib, 200 mg/d, and rofecoxib, 12.5 mg, for symptomatic knee OA.