Pain management in osteoarthritis: a focus on onset of efficacy--a comparison of rofecoxib, celecoxib, acetaminophen, and nabumetone across four clinical trials.

UNLABELLED: We compared onset of efficacy (during days 1 to 6) of 2 coxibs (rofecoxib, celecoxib) with acetaminophen and nabumetone by using a prespecified approach to data from 4 similarly designed 6-week randomized osteoarthritis trials. In 2 trials, rofecoxib (12.5 mg and 25 mg once daily) was compared with celecoxib (200 mg once daily) and acetaminophen (4000 mg daily). In the other 2 trials, rofecoxib (12.5 mg) was compared with nabumetone (1000 mg once daily) and placebo. Efficacy end points included Patient Global Response to Therapy and Western Ontario and McMaster Osteoarthritis Index scores. Rofecoxib (12.5- and 25-mg doses) consistently demonstrated a faster onset of osteoarthritis (OA) efficacy than the comparator drugs during the first 6 days of therapy of OA patients experiencing "flare." Acetaminophen resulted in the slowest onset of efficacy. There was a strong correlation (0.7) between efficacy response during days 1 to 6 and that averaged over 6 weeks. Rates of discontinuation as a result of lack of efficacy were significantly lower (P < .02) for each of the coxib-treated groups compared with acetaminophen and for rofecoxib 12.5 mg (P = .01) compared with nabumetone. Rofecoxib treatment, with its faster onset of OA efficacy and lower rates of related discontinuations, might provide efficacy advantages in the treatment of OA pain.

PERSPECTIVE: The efficacy of rofecoxib, celecoxib, nabumetone, and acetaminophen is established for the majority of OA patients within the first 6 days of therapy, and this predicts efficacy during the longer term. Rofecoxib provides significantly faster time to onset of efficacy and better improvement on multiple measures versus the comparators.