A Randomized, Multicenter, Phase III Trial to Evaluate the Efficacy and Safety of Polmacoxib Compared with Celecoxib and Placebo for Patients with Osteoarthritis

BACKGROUND: The aim of this study was to evaluate the safety and analgesic efficacy of polmacoxib 2 mg versus placebo in a superiority comparison or versus celecoxib 200 mg in a noninferiority comparison in patients with osteoarthritis (OA). METHODS: This study was a 6-week, phase III, randomized, double-blind, and parallel-group trial followed by an 18-week, single arm, open-label extension. Of the 441 patients with knee or hip OA screened, 362 were randomized; 324 completed 6 weeks of treatment and 220 completed the extension. Patients were randomized to receive oral polmacoxib 2 mg (n = 146), celecoxib 200 mg (n = 145), or placebo (n = 71) once daily for 6 weeks. During the extension, all participants received open-label polmacoxib 2 mg. The primary endpoint was the change in Western Ontario and McMaster Universities (WOMAC)-pain subscale score from baseline to week 6. Secondary endpoints included WOMAC-OA Index, OA subscales (pain, stiffness, and physical function) and Physician's and Subject's Global Assessments at weeks 3 and 6. Other outcome measures included adverse events (AEs), laboratory tests, vital signs, electrocardiograms, and physical examinations. RESULTS: After 6 weeks, the polmacoxib-placebo treatment difference was −2.5 (95% confidence interval [CI], −4.4 to −0.6; p = 0.011) and the polmacoxib-celecoxib treatment difference was 0.6 (CI, −0.9 to 2.2; p = 0.425). According to Physician's Global Assessments, more subjects were “much improved” at week 3 with polmacoxib than with celecoxib or placebo. Gastrointestinal and general disorder AEs occurred with a greater frequency with polmacoxib or celecoxib than with placebo. CONCLUSIONS: Polmacoxib 2 mg was relatively well tolerated and demonstrated efficacy superior to placebo and noninferior to celecoxib after 6 weeks of treatment in patients with OA. The results obtained during the 18-week trial extension with polmacoxib 2 mg were consistent with those observed during the 6-week treatment period, indicating that polmacoxib can be considered safe for long-term use based on this relatively small scale of study in a Korean population. More importantly, the results of this study showed that polmacoxib has the potential to be used as a pain relief drug with reduced gastrointestinal side effects compared to traditional nonsteroidal anti-inflammatory drugs for OA.