Polmacoxib: A Review of the Newer Non-steroidal Anti-inflammatory Drug in Osteoarthritis.

Osteoarthritis represents a huge socioeconomic burden and has a significant impact on daily life and productivity. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in the management of osteoarthritis to curb inflammation, pain, and stiffness and improve physical function. However, due to the various side effects, most healthcare professionals avoid using NSAIDs for a long period. Nonselective cyclooxygenase (COX) inhibitors and cyclooxygenase-1 (COX-1) inhibitors are associated with increased gastrointestinal adverse effects due to the inhibition of prostaglandins, which are responsible for protecting the gastric mucosa. Cyclooxygenase-2 (COX-2) inhibitors are associated with an increased incidence of adverse cardiovascular effects due to their COX-2 inhibitory activity in the circulatory system. Therefore, there is a need for a newer NSAID that has a better safety profile to be used in osteoarthritis. Polmacoxib is a new, orally active, first-in-class NSAID that is a dual inhibitor of COX-2 and carbonic anhydrase (CA). The dual mode of action exhibited by polmacoxib is expected to minimize adverse cardiovascular effects while achieving maximum effectiveness in inflamed osteoarthritic joints. This article aims to review the pharmacological properties, clinical efficacy, and safety data of polmacoxib in osteoarthritis.

Population Pharmacokinetic and Pharmacodynamic Analysis of Polmacoxib in Healthy Volunteers and Patients With Osteoarthritis.

PURPOSE: Polmacoxib, a new coxib dually inhibiting cyclooxygenase-2 and carbonic anhydrase I/II, was recently approved for osteoarthritis treatment in South Korea. This study explored the population pharmacokinetic and pharmacodynamic characteristics of polmacoxib. METHODS: Nonlinear mixed-effects modeling was performed using pooled pharmacokinetic data from a Phase I study in healthy individuals and pharmacokinetic properties and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) data from a Phase IIb study in patients with osteoarthritis. Pharmacodynamic models for WOMAC were sequentially fit using individual pharmacokinetic parameter estimates. FINDINGS: Polmacoxib concentrations in whole blood were adequately described by the 2-compartment model, with mixed zero- and first-order absorption kinetics. Iron concentration was the significant covariate associated with clearance of polmacoxib. The relationship between the whole blood concentration of polmacoxib and WOMAC was best described by a 2-effect compartment model that consisted of central and peripheral compartments with the rate constant of 0.408 min-1 for distribution to the central effect compartment. A decrease in WOMAC was linked to the central effect site compartment concentration through an ordinary maximum effect model with an effect site concentration needed to achieve 50% of the maximum effect of 508 ng/mL. IMPLICATIONS: The current model accurately characterized the pharmacokinetic and pharmacodynamic properties of polmacoxib and could provide a basis for individualized drug therapy.

An Unusual Case of Colon Perforation With Multiple Transmural Ulcers After Use of Polmacoxib and Everolimus in a Metastatic Breast Cancer Patient.

Everolimus (Afinitor) is an inhibitor of mammalian target of rapamycin. Polmacoxib (Acelex) is a nonsteroidal anti-inflammatory drug that belongs to the cyclooxygenase-2 (COX-2) inhibitor family and is mainly used for treatment of arthritis. Intestinal perforation has not been reported previously as a complication of everolimus, and perforation of the lower intestinal tract caused by a selective COX-2 inhibitor is extremely rare. We present here a case of colon perforation that occurred after use of polmacoxib in a metastatic breast cancer patient who had been treated with everolimus for the preceding six months.

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.

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.

Structural insight into the inhibition of carbonic anhydrase by the COX-2-selective inhibitor polmacoxib (CG100649).

Polmacoxib is not only a selective COX-2 inhibitor but also a potent inhibitor of carbonic anhydrases (CAs). Both CA I and CA II are highly expressed in the GI tract and kidneys, organs that are also thought to be the sites at which selective COX-2 inhibitors show their side effects. By inhibition assays, we show that both CA I and CA II are strongly inhibited by polmacoxib, while CA II also demonstrates direct competition with COX-2. To understand, at the molecular level, how polmacoxib interacts with CA I and II, we solved the first crystal structures of CA I and CA II in complex with polmacoxib, at 2.0 Å and 1.8 Å, respectively. Interestingly, three polmacoxib molecules bind to the active site of CA I, whereas only one molecule binds CA II. In the active site, the three molecules of polmacoxib organize itself along hydrophobic interaction as "stack-on-formation", and fully occupy a cone-shaped active pocket in CA I. The binding mode of polmacoxib to CA II was found different than its binding to celecoxib and valdecoxib. Our results provide structural insight into inhibition of CA I and CA II by polmacoxib, to assess its potential clinical efficacy.