Tolerability and efficacy of nabumetone and naproxen in the treatment of rheumatoid arthritis.

OBJECTIVE

The purpose of this study was to compare the tolerability and efficacy of nabumetone and naproxen in the treatment of patients with rheumatoid arthritis (RA). The occurrence of gastrointestinal (GI) adverse events was compared.

BACKGROUND

Nonsteroidal anti-inflammatory drugs (NSAIDs) have similar efficacy at equipotent doses, but the therapeutic response to various NSAIDs often differs in individual patients.

METHODS

This was a 3-month, randomized, double-blind, multicenter, parallel-group study conducted in adult patients with RA. The study had 2 phases: a 3- to 14-day washout period and a 12-week treatment period. During the treatment phase, the tolerability and efficacy of nabumetone 2000 mg/d were compared with those of naproxen 1000 mg/d. The change from baseline in efficacy variables, including global assessments, number of tender or swollen joints, and pain, was evaluated. The study was sized to provide an 80% power to detect a 15% difference in the percentage improvement on the physician's global assessment (alpha = 0.05). GI safety was assessed by monitoring the occurrence of clinically important adverse GI events.

RESULTS

A total of 346 RA patients at 31 US rheumatology centers were randomly assigned to treatment (173 patients per group). The study population was predominantly white (87.0%) and female (70.5%), with a mean age of 54 years. Both treatments improved the signs and symptoms of RA, with no statistically significant differences between groups for any efficacy variables. No serious GI adverse events occurred with either NSAID. The most frequent treatment-related adverse events in both groups were predominantly GI in origin, as were those that resulted in withdrawal from the study. Diarrhea with lower abdominal pain was the most common adverse event in the nabumetone group; upper abdominal pain was the most common adverse event in the naproxen group. The only significant difference between the 2 groups was a higher incidence of diarrhea (P < 0.01) in patients receiving nabumetone.

CONCLUSIONS

Nabumetone 2000 mg/d was as effective as naproxen 1000 mg/d in relieving the signs and symptoms of RA. In this study, no serious GI adverse events were observed with either NSAID, but nabumetone was associated with a higher incidence of diarrhea.