Efficacy and safety of etoricoxib 30 mg and celecoxib 200 mg in the treatment of osteoarthritis in two identically designed, randomized, placebo-controlled, non-inferiority studies

A turbulent decade for NSAIDs: update on current concepts of classification, epidemiology, comparative efficacy, and toxicity

Non-steroidal anti-inflammatory drugs (NSAIDs) represent a diverse class of drugs and are among the most commonly used analgesics for arthritic pain worldwide, though long-term use is associated with a spectrum of adverse effects. The introduction of cyclooxygenase-2-selective NSAIDs early in the last decade offered an alternative to traditional NSAIDs with similar efficacy and improved gastrointestinal tolerability; however, emerging concerns about cardiovascular safety resulted in the withdrawal of two agents (rofecoxib and valdecoxib) in the mid-2000s and, subsequently, in an overall reduction in NSAID use. It is now understood that all NSAIDs are associated with some varying degree of gastrointestinal and cardiovascular risk. Guidelines still recommend their use, but little is known of how patients use these agents. While strategies and guidelines aimed at reducing NSAID-associated complications exist, there is a need for evidence-based algorithms combining cardiovascular and gastrointestinal factors that can be used to aid treatment decisions at an individual patient level.

Risk management profile of etoricoxib: an example of personalized medicine

The development of nonsteroidal anti-inflammatory drugs (NSAIDs) selective for cyclooxygenase (COX)-2 (named coxibs) has been driven by the aim of reducing the incidence of serious gastrointestinal (GI) adverse events associated with the administration of traditional (t) NSAIDs – mainly dependent on the inhibition of COX-1 in GI tract and platelets. However, their use has unravelled the important protective role of COX-2 for the cardiovascular (CV) system, mainly through the generation of prostacyclin. In a recent nested-case control study, we found that patients taking NSAIDs (both coxibs and tNSAIDs) had a 35% increase risk of myocardial infarction. The increased incidence of thrombotic events associated with profound inhibition of COX-2-dependent prostacyclin by coxibs and tNSAIDs can be mitigated, even if not obliterated, by a complete suppression of platelet COX-1 activity. However, most tNSAIDs and coxibs are functional COX-2 selective for the platelet (ie, they cause a profound suppression of COX-2 associated with insufficient inhibition of platelet COX-1 to translate into inhibition of platelet function), which explains their shared CV toxicity. The development of genetic and biochemical markers will help to identify the responders to NSAIDs or who are uniquely susceptible at developing thrombotic or GI events by COX inhibition. We will describe possible strategies to reduce the side effects of etoricoxib by using biochemical markers of COX inhibition, such as whole blood COX-2 and the assessment of prostacyclin biosynthesis in vivo.

Fixed-dose combination of enteric-coated naproxen and immediate-release esomeprazole has comparable efficacy to celecoxib for knee osteoarthritis: two randomized trials

OBJECTIVE

To demonstrate that a fixed-dose combination of enteric-coated naproxen 500 mg and immediate-release esomeprazole magnesium 20 mg has comparable efficacy to celecoxib for knee osteoarthritis.

RESEARCH DESIGN AND METHODS

Two randomized, double-blind, parallel-group, placebo-controlled, multicenter phase III studies (PN400-307 and PN400-309) enrolled patients aged ≥50 years with symptomatic knee osteoarthritis. Following an osteoarthritis flare, patients received naproxen/esomeprazole magnesium twice daily, celecoxib 200 mg once daily, or placebo for 12 weeks.

CLINICAL TRIAL REGISTRATION

NCT00664560 and NCT00665431.

MAIN OUTCOME MEASURES

Three co-primary efficacy endpoints were mean change from baseline to week 12 in Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain and function subscales, and Patient Global Assessment of osteoarthritis using a visual analog scale (PGA-VAS).

RESULTS

In Study 307, 619 patients were randomized and 614 treated. In Study 309, 615 patients were randomized and 610 treated. Both naproxen/esomeprazole magnesium and celecoxib were associated with improvements (least squares mean change from baseline to week 12) in WOMAC pain (Study 307: -42.0 and -41.8, respectively; Study 309: -44.2 and -42.9, respectively), WOMAC function (Study 307: -36.4 and -36.3, respectively; Study 309: -38.9 and -36.8, respectively), and PGA-VAS (Study 307: 21.2 and 21.6, respectively; Study 309: 29.0 and 25.6, respectively). A prespecified non-inferiority margin of 10 mm between naproxen/esomeprazole magnesium and celecoxib was satisfied for each co-primary endpoint at week 12 in both studies. Significant improvements were observed with naproxen/esomeprazole magnesium versus placebo in both studies (p < 0.05). Celecoxib was significantly different from placebo in Study 307 (p < 0.05); however, the improvements were not significant in Study 309. Acetaminophen use and patient expectation of receiving active treatment (80% probability) may have contributed to a high placebo response observed.

CONCLUSIONS

Naproxen/esomeprazole magnesium has comparable efficacy to celecoxib for the management of pain associated with osteoarthritis of the knee over 12 weeks.

Osteoarthritis subpopulations and implications for clinical trial design

Treatment guidelines for osteoarthritis have stressed the need for research on clinical predictors of response to different treatments. However, identifying such clinical predictors of response is less easy than it seems, and there is not a given classification of osteoarthritis subpopulations. This review article highlights the key methodical issues when analyzing and designing clinical studies to detect important subgroups with respect to treatment effect. In addition, we discuss the main osteoarthritis subpopulations and give examples of how specific treatment effects in these subpopulations have been assessed.

Comparative efficacy and tolerability of 5-Loxin and AflapinAgainst osteoarthritis of the knee: a double blind, randomized, placebo controlled clinical study

Aflapin(®) is a novel synergistic composition derived from Boswellia serrata gum resin (Indian Patent Application No. 2229/CHE/2008). Aflapin is significantly better as an anti-inflammatory agent compared to the Boswellia extracts presently available in the market. A 90-day, double-blind, randomized, placebo-controlled study was conducted to evaluate the comparative efficacy and tolerability of 5-Loxin(®) and Aflapin(®) in the treatment of osteoarthritis (OA) of the knee (Clinical trial registration number: ISRCTN80793440). Sixty OA subjects were included in the study. The subjects received either 100 mg (n=20) of 5-Loxin(®) or 100 mg (n=20) of Aflapin(®) or a placebo (n=20) daily for 90 days. Each patient was evaluated for pain and physical functions by using the standard tools (visual analog scale, Lequesne's Functional Index, and Western Ontario and McMaster Universities Osteoarthritis Index) at the baseline (day 0), and at days 7, 30, 60 and 90. A battery of biochemical parameters in serum, urine and hematological parameters in citrated whole blood were performed to assess the safety of 5-Loxin(®) and Aflapin(®) in OA subjects. Fifty seven subjects completed the study. At the end of the study, both 5-Loxin(®) and Aflapin conferred clinically and statistically significant improvements in pain scores and physical function scores in OA subjects. Interestingly, significant improvements in pain score and functional ability were recorded as early as 7 days after initiation of the study in the treatment group supplemented with 100 mg Aflapin. Corroborating the improvements in pain scores in treatment groups, our in vitro studies provide evidences that Aflapin(®) is capable of inhibiting cartilage degrading enzyme MMP-3 and has the potential to regulate the inflammatory response by inhibiting ICAM-1. Aflapin(®) and 5-Loxin(®) reduce pain and improve physical functions significantly in OA subjects. Aflapin exhibited better efficacy compared to 5-Loxin(®). In comparison with placebo, the safety parameters were almost unchanged in the treatment groups. Hence both 5-Loxin(®) and Aflapin(®) are safe for human consumption.

Comparing etoricoxib and celecoxib for preemptive analgesia for acute postoperative pain in patients undergoing arthroscopic anterior cruciate ligament reconstruction: a randomized controlled trial

Background

The efficacy of selective cox-2 inhibitors in postoperative pain reduction were usually compared with conventional non-selective conventional NSAIDs or other types of medicine. Previous studies also used selective cox-2 inhibitors as single postoperative dose, in continued mode, or in combination with other modalities. The purpose of this study was to compare analgesic efficacy of single preoperative administration of etoricoxib versus celecoxib for post-operative pain relief after arthroscopic anterior cruciate ligament reconstruction.

Methods

One hundred and two patients diagnosed as anterior cruciate ligament injury were randomized into 3 groups using opaque envelope. Both patients and surgeon were blinded to the allocation. All of the patients were operated by one orthopaedic surgeon under regional anesthesia. Each group was given either etoricoxib 120 mg., celecoxib 400 mg., or placebo 1 hour prior to operative incision. Post-operative pain intensity, time to first dose of analgesic requirement and numbers of analgesic used for pain control and adverse events were recorded periodically to 48 hours after surgery. We analyzed the data according to intention to treat principle.

Results

Among 102 patients, 35 were in etoricoxib, 35 in celecoxib and 32 in placebo group. The mean age of the patients was 30 years and most of the injury came from sports injury. There were no significant differences in all demographic characteristics among groups. The etoricoxib group had significantly less pain intensity than the other two groups at recovery room and up to 8 hours period but no significance difference in all other evaluation point, while celecoxib showed no significantly difference from placebo at any time points. The time to first dose of analgesic medication, amount of analgesic used, patient's satisfaction with pain control and incidence of adverse events were also no significantly difference among three groups.

Conclusions

Etoricoxib is more effective than celecoxib and placebo for using as preemptive analgesia for acute postoperative pain control in patients underwent arthroscopic anterior cruciate ligament reconstruction.

Trial registration number

NCT01017380

Etoricoxib improves pain, function and quality of life: results of a real-world effectiveness trial

OBJECTIVE

To evaluate the effectiveness and tolerability of etoricoxib in patients with osteoarthritis (OA) with suboptimal response to existing pain regimens.

METHODS

A multicenter, prospective, open-label, single-arm study. OA patients (n = 500) taking nonsteroidal anti-inflammatory drugs (NSAIDs) or other analgesics who had inadequate response as determined by their physicians (>or= 40 mm on a 0-100 mm pain scale) were switched directly to etoricoxib 60 mg once daily for 4 weeks without prior medication washout. The primary endpoint was the percentage of patients with >or= 30% improvement in Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) pain walking on a flat surface after 4 weeks of treatment. Other endpoints included WOMAC Pain, Stiffness, and Physical Function subscales, Brief Pain Inventory (BPI), investigator's global assessment of response to therapy (IGART), the Treatment Satisfaction Questionnaire for Medication (TSQM) and Short Form 36 (SF36). Safety and tolerability were assessed by collecting adverse events.

RESULTS

After switching to etoricoxib, 52% (95% confidence interval: 47%, 57%) of patients reported a clinically meaningful reduction (>or= 30%) for WOMAC pain walking on a flat surface. Disability in daily activities and pain interference were significantly improved (P < 0.0001). IGART scores improved after the switch to etoricoxib (P < 0.05). Results from TSQM demonstrated that patient perceptions of effectiveness, convenience and overall satisfaction increased. Etoricoxib was generally well tolerated in most patients. The most commonly reported adverse event was edema (4.2%).

CONCLUSIONS

In OA patients experiencing inadequate relief from a wide variety of analgesics, pain, function, quality of life, and treatment satisfaction significantly improved when switched to etoricoxib.

Influence of flare design on symptomatic efficacy of non-steroidal anti-inflammatory drugs in osteoarthritis: a meta-analysis of randomized placebo-controlled trials

INTRODUCTION

Non-steroidal anti-inflammatory drugs' (NSAIDs) symptomatic efficacy in osteoarthritis (OA) is often assessed in trials with a "flare design", i.e., including only patients with an increase in their pain after stopping their usual treatment (NSAIDs or analgesic).

OBJECTIVE

To evaluate the influence of the "flare design" on NSAIDs apparent symptomatic efficacy in OA.

SEARCH STRATEGY

a systematic literature research was performed in Medline, EMBASE and The Cochrane Register up to March 2009. All randomized controlled trials comparing NSAIDs vs placebo symptomatic efficacy in hip, knee, or digital OA were included.

DATA COLLECTION AND ANALYSIS

efficacy was evaluated on pain (visual analog scale), and on function (Western Ontario and McMaster Universities OA index or Lequesne index). The magnitude of the treatment effect was evaluated by calculating Cohen's effect size (ES). Meta-analysis of ES according to flare design yes/no was performed.

RESULTS

Among the 343 identified studies, 33 (20,915 patients) were included: 27 (18,667 patients) vs 6 (2248 patients) respectively in the group with vs without "flare design". Populations were comparable in each group. ESs were, for pain, -0.66 (95% confidence interval, -0.71 to -0.61), vs -0.45 (-0.54 to -0.36) in the flare design vs "no flare design" group, and for function, -0.50 (-0.55 to -0.44) vs -0.25 (-0.36 to -0.14) respectively.

CONCLUSION

Our study suggests that the flare design used in clinical trials evaluating NSAIDs results in a treatment effect of higher magnitude. These results should be considered when designing a trial and/or interpreting the results of a trial.

A walking model to assess the onset of analgesia in osteoarthritis knee pain

OBJECTIVE

To assess a walking model utilizing a set of standardized treadmill walks to measure acute analgesic response in osteoarthritis (OA) of the knee.

DESIGN

Randomized, double-blind, placebo-controlled, multiple dose, three-period crossover study. Patients > or =45 years of age (N=22) with symptomatic knee OA were randomized to naproxen 500 mg bid, tramadol/acetaminophen 37.5 mg/325 mg in forced titration, or placebo in each of three periods. Patients performed multiple 20-minute treadmill walks on Day 1 and Day 3 at a consistent self-selected pace predetermined at screening. Pain intensity (PI) during the walks was assessed on an 11-point numerical rating scale at 0, 3, 6, 9, 12, 15, 18, and 20 min. The primary endpoint was the time-weighted average (TWA) change from baseline PI on Day 3 for the two self-paced walks for the active treatments vs placebo. Time to moderate pain (TTMP) was a key secondary endpoint.

RESULTS

Compared with placebo, the TWA change from baseline PI on Day 3 was significantly better with tramadol/acetaminophen (P=0.043) but not with naproxen (P=0.089). TWA change from baseline on Day 1 was also significantly better with both tramadol/acetaminophen (P=0.001) and naproxen (P=0.048) compared with placebo. TTMP was significantly better for tramadol/acetaminophen and naproxen than placebo (P<0.001 to P=0.015) for walks on Day 1 after a single dose and on Day 3.

CONCLUSIONS

This novel OA pain model was able to discriminate both tramadol/acetaminophen and naproxen from placebo after single and multiple doses. ClinicalTrials.gov identifier: NCT00772967.

Responder analysis for pain relief and numbers needed to treat in a meta-analysis of etoricoxib osteoarthritis trials: bridging a gap between clinical trials and clinical practice

BACKGROUND

Population mean changes from clinical trials are difficult to apply to individuals in clinical practice. Responder analysis may be better, but needs validating for level of response and treatment duration.

METHODS

The numbers of patients with pain relief over baseline (> or =15%, > or =30%, > or =50%, > or =70%) at 2, 4, 8 and 12 weeks of treatment were obtained using the WOMAC 100 mm visual analogue pain subscale score for each treatment group in seven randomised placebo-controlled trials of etoricoxib in osteoarthritis lasting > or =6 weeks. Dropouts were assigned 0% improvement from baseline from then on. The numbers needed to treat (NNTs) were calculated at each level of response and time point.

RESULTS

3554 patients were treated with placebo, etoricoxib 30 mg and 60 mg, celecoxib 200 mg, naproxen 1000 mg or ibuprofen 2400 mg daily. Response rates fell with increasing pain relief: 60-80% experienced minimally important pain relief (> or =15%), 50-60% moderate pain relief (> or =30%), 40-50% substantial pain relief (> or =50%) and 20-30% extensive pain relief (> or =70%). NNTs for etoricoxib, celecoxib and naproxen were stable over 2-12 weeks. Ibuprofen showed lessening of effectiveness with time.

CONCLUSION

Responder rates and NNTs are reproducible for different levels of response over 12 weeks and have relevance for clinical practice at the individual patient level. An average 10 mm improvement in pain equates to almost one in two patients having substantial benefit.

Do COX-2 inhibitors raise blood pressure more than nonselective NSAIDs and placebo? An updated meta-analysis

BACKGROUND

Both COX-2 selective inhibitors (coxibs) and nonselective (ns)-NSAIDs elevate blood pressure (BP) and this may contribute to excess cardiovascular (CV) events. A number of recent large-scale randomized clinical trials (RCTs) comparing coxibs (including newer agents, lumiracoxib and etoricoxib) to both ns-NSAIDs and placebo have been reported, permitting an update to earlier BP analyses of these agents.

DATA SOURCES/SYNTHESIS

Our search yielded 51 RCTs involving coxibs published before April 2008 with a total of 130 541 participants in which BP data were available. The Der Simonian and Laird random effects method for dichotomous variables was used to produce risk ratios (RR) for development of hypertension.

RESULTS

For coxibs versus placebo, there was a RR of 1.49 (1.18-1.88, P = 0.04) in the development of new hypertension. For coxibs versus ns-NSAIDs, the RR was 1.12 (0.93-1.35, P = 0.23). These results were mainly driven by rofecoxib, with a RR of 1.87 (1.63-2.14, P = 0.08) versus placebo, and etoricoxib, with a RR of 1.52 (1.39-1.66, P = 0.01) versus ns-NSAID.

CONCLUSION

On the basis of this updated meta-analysis, coxibs appear to produce greater hypertension than either ns-NSAIDs or placebo. However, this response was heterogeneous, with markedly raised BP associated with rofecoxib and etoricoxib, whereas celecoxib, valdecoxib and lumiracoxib appeared to have little BP effect. The relationship of this increased risk of hypertension to subsequent adverse CV outcomes requires further investigation and prospective RCTs.

Etoricoxib: a review of its use in the symptomatic treatment of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis and acute gouty arthritis

Etoricoxib is a selective cyclo-oxygenase (COX)-2 inhibitor, approved in Europe for the symptomatic treatment of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis and acute gouty arthritis. Etoricoxib provided similar symptomatic relief to nonselective NSAIDs in patients with these conditions, and to celecoxib in patients with osteoarthritis. The drug was associated with fewer uncomplicated upper gastrointestinal (GI) adverse events than nonselective NSAIDs, and was noninferior to diclofenac in terms of the rate of thrombotic cardiovascular (CV) events. Etoricoxib may be considered as a treatment option for patients requiring NSAID therapy, particularly those at risk of upper GI events, after careful consideration of significant risk factors for CV events (including uncontrolled hypertension). As with all NSAIDs, the potential GI and CV risks of treatment with etoricoxib should be weighed against the potential benefits in individual patients, and it should be administered at the lowest effective dose for as short a duration as possible.

Effects of celecoxib on volumes of hematoma and edema in patients with primary intracerebral hemorrhage

Celecoxib is a potent anti-inflammatory drug with a safety profile that has been well-demonstrated in several human diseases and is reported to have beneficial effects in a rat model of intracerebral hemorrhage (ICH). We investigated the efficacy and safety of celecoxib treatment in patients with primary ICH. We retrospectively collected clinical data of patients admitted within 48 h after the onset of primary ICH. We classified the patients administered celecoxib (400 mg/day) for > or =7 days as the celecoxib-treated group (n=17) and classified the patients who were not administered celecoxib as the control group (n=17). The volumes of hematoma and edema were analyzed with initial and follow-up (at approximately 7 days) brain CT scans. Baseline characteristics, initial severity of neurologic sequelae, and initial volumes of the lesions were not different between the groups. Celecoxib treatment significantly reduced the volumes of edema noted on follow-up brain CT scans as compared with the volumes in the control group (30.2+/-17.7 vs. 55.5+/-40.6 mL, p=0.027) and also reduced the ratio of initial hematoma and edema volumes vs. the follow-up volumes as compared with those of the control group (hematoma, 0.90+/-0.29 vs. 1.54+/-1.12, p=0.035; edema, 0.95+/-0.32 vs. 2.08+/-0.88, p<0.001). The incidences of adverse events during the admission were not different between the groups. These results suggest that celecoxib may be safe and efficacious in patients with primary ICH. To confirm this notion, a large-sized prospective study should be performed.

Contrast-enhanced ultrasound in monitoring the efficacy of a bradykinin receptor 2 antagonist in painful knee osteoarthritis compared with MRI

OBJECTIVES

To evaluate contrast-enhanced ultrasound (CE-US) as a monitoring tool to assess hypervascularisation of synovial processes in knee osteoarthritis (OA) treated with intra-articular injections of the bradykinin-receptor 2 antagonist icatibant compared to contrast-enhanced magnetic resonance imaging (CE-MRI).

PATIENTS AND METHODS

In a randomised, double-blind, placebo-controlled trial, 41 patients with painful knee OA underwent US (12.5 MHz for B-mode and 3-8 MHz for CE-US), and 36 of the patients underwent additional MRI (0.2T) at baseline and after 3 injections of the study drug (after a mean of 22.2 days). A total of 15 patients received placebo (group A), 12 patients 500 microg icatibant (group B) and 14 patients 2000 microg icatibant (group C). Pain and the synovial process (B-mode, power Doppler US (PD-US), CE-US, CE-MRI) were assessed at both time points.

RESULTS

At baseline, the placebo group showed more activity in terms of effusion in the superior and lateral recess in ultrasound as well as in PD-US in the lateral recess. Pain improved significantly in all subgroups. Effect sizes were 0.43 (pain at rest) and 0.52 (pain during activity) in group B vs 0.48 and 1.11 in group C. There was no change of US and MRI parameters. We found moderate to good correlation (r) and kappa values (kappa) for effusion in the superior recess (r = 0.591, k = 0.453), effusion in the lateral recess (r = 0.304, k = 0.440) and contrast enhancement (r = 0.601, k = 0.242) between US and MRI.

CONCLUSIONS

Our results show that CE-US and CE-MRI have good agreement in assessing inflammatory changes in knee OA. For the 41 patients with OA, an analgesic effect of icatibant could clearly be shown, especially for pain during activity in the high dose icatibant group. However, we could not find an anti-inflammatory effect of icatibant by CE-US compared to CE-MRI.

Responder analysis and correlation of outcome measures: pooled results from two identical studies comparing etoricoxib, celecoxib, and placebo in osteoarthritis

OBJECTIVES

To determine the proportion of responders in two identical osteoarthritis (OA) trials using Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International (OMERACT-OARSI) criteria and to assess the comparability and correlation of individual component measurements.

METHODS

Data were pooled from two identical 26-week, double-blind, randomized, parallel, multicenter trials comparing once daily etoricoxib 30 mg (N=475), celecoxib 200 mg (N=488), and placebo (N=244) in patients with OA of the knee or hip. OMERACT-OARSI criteria were (1) improvement in pain or physical function > or =50% and an absolute change > or =20 mm on a 100-mm visual analog scale (VAS); or (2) improvement of > or =20% and with an absolute change > or =10 mm in at least two of the following three categories: pain, physical function, and patient's global assessment. Correlations were assessed between endpoints measured as time-weighted average change from baseline over 12 weeks using Pearson's correlation coefficient (r).

RESULTS

There were significantly greater proportions of responders in the etoricoxib (66.2%) and celecoxib (63.5%) groups compared with the placebo group (43.0%; P<0.001). There was no difference between the two active treatment groups. There was high correlation between pain and physical function (r=0.903), pain and global assessment (r=0.778), and physical function and global assessment (r=0.820). There was high sensitivity (75-87%) and specificity (80-96%) for changes in individual component measurements to predict OMERACT-OARSI responders.

CONCLUSIONS

Significantly more patients receiving etoricoxib or celecoxib than placebo were OMERACT-OARSI responders. The high correlation between individual scales composing this composite response measurement suggests some redundancies between individual components, particularly between pain and physical function.

A double blind, randomized, placebo controlled study of the efficacy and safety of 5-Loxin for treatment of osteoarthritis of the knee

Introduction

5-Loxin^® is a novel Boswellia serrata extract enriched with 30% 3-O-acetyl-11-keto-beta-boswellic acid (AKBA), which exhibits potential anti-inflammatory properties by inhibiting the 5-lipoxygenase enzyme. A 90-day, double-blind, randomized, placebo-controlled study was conducted to evaluate the efficacy and safety of 5-Loxin^® in the treatment of osteoarthritis (OA) of the knee.

Methods

Seventy-five OA patients were included in the study. The patients received either 100 mg (n = 25) or 250 mg (n = 25) of 5-Loxin^® daily or a placebo (n = 25) for 90 days. Each patient was evaluated for pain and physical functions by using the standard tools (visual analog scale, Lequesne's Functional Index, and Western Ontario and McMaster Universities Osteoarthritis Index) at the baseline (day 0), and at days 7, 30, 60 and 90. Additionally, the cartilage degrading enzyme matrix metalloproteinase-3 was also evaluated in synovial fluid from OA patients. Measurement of a battery of biochemical parameters in serum and haematological parameters, and urine analysis were performed to evaluate the safety of 5-Loxin^® in OA patients.

Results

Seventy patients completed the study. At the end of the study, both doses of 5-Loxin^® conferred clinically and statistically significant improvements in pain scores and physical function scores in OA patients. Interestingly, significant improvements in pain score and functional ability were recorded in the treatment group supplemented with 250 mg 5-Loxin^® as early as 7 days after the start of treatment. Corroborating the improvements in pain scores in treatment groups, we also noted significant reduction in synovial fluid matrix metalloproteinase-3. In comparison with placebo, the safety parameters were almost unchanged in the treatment groups.

Conclusion

5-Loxin^® reduces pain and improves physical functioning significantly in OA patients; and it is safe for human consumption. 5-Loxin^® may exert its beneficial effects by controlling inflammatory responses through reducing proinflammatory modulators, and it may improve joint health by reducing the enzymatic degradation of cartilage in OA patients.

Trail Registration

(Clinical trial registration number: ISRCTN05212803.)

COX-2 selective inhibitors in the treatment of osteoarthritis

OBJECTIVES

To assess the efficacy of cyclooxygenase-2 selective inhibitors (coxibs) in osteoarthritis (OA) and their gastrointestinal, cardiovascular, renovascular, and hepatic side effects compared with traditional nonsteroidal antiinflammatory drugs (NSAIDs) and acetaminophen.

METHODS

Bibliographic database searches for randomized controlled trials, meta-analyses, and literature reviews.

RESULTS

Coxibs are comparable to traditional NSAIDs, providing moderate benefit for OA patients in pain and function versus placebo. NSAIDs, including coxibs, are superior to acetaminophen for OA, particularly in patients with moderate to severe pain. Coxibs decrease gastroduodenal ulcers (74% relative risk reduction) and ulcer complications (61% reduction) versus traditional NSAIDs. Meta-analysis of randomized trials indicates that coxibs increase the risk of myocardial infarctions approximately twofold versus placebo and versus naproxen, but do not increase the risk versus nonnaproxen NSAIDs. NSAIDs, including coxibs, commonly cause fluid retention and increase blood pressure and uncommonly induce congestive heart failure or significant renal dysfunction; risk factors include advanced age, hypertension, and heart or kidney disease. NSAIDs are a rare cause of clinical hepatotoxicity (<1 liver-related death per 100,000 NSAID users in clinical studies). Increased rates of aminotransferase elevations occur with rofecoxib (2%) and high-dose lumiracoxib (3%), and postmarketing cases of clinical liver injury with lumiracoxib have been reported recently.

CONCLUSIONS

Coxibs are as effective as traditional NSAIDs and superior to acetaminophen for the treatment of OA. Coxibs cause fewer gastrointestinal complications than traditional NSAIDs. Coxibs increase cardiovascular risk versus placebo and naproxen-but probably not versus nonnaproxen NSAIDs. Blood pressure commonly increases after initiation of selective or nonselective NSAIDs, especially in hypertensive patients.

Clinical use and pharmacological properties of selective COX-2 inhibitors

Selective COX-2 inhibitors (coxibs) are approved for the relief of acute pain and symptoms of chronic inflammatory conditions such as osteoarthritis (OA) and rheumatoid arthritis (RA). They have similar pharmacological properties but a slightly improved gastrointestinal (GI) safety profile if compared to traditional nonsteroidal anti-inflammatory drugs (tNSAIDs). However, long-term use of coxibs can be associated with an increased risk for cardiovascular (CV) adverse events (AEs). For this reason, two coxibs were withdrawn from the market. Currently celecoxib, etoricoxib, and lumiracoxib are used. These three coxibs differ in their chemical structure and selectivity for COX-2, which might explain some of their pharmacological features. Following oral administration, the less lipophilic celecoxib has a lower bioavailability (20-40%) than the other two coxibs (74-100%). All are eliminated by hepatic metabolism involving mainly CYP2C9 (celecoxib, lumiracoxib) and CYP3A4 (etoricoxib). Elimination half-life varies from 5 to 8 h (lumiracoxib), 11 to 16 h (celecoxib) and 19 to 32 h (etoricoxib). In patients with liver disease, plasma levels of celecoxib and etoricoxib are increased about two-fold. Clinical efficacies of the coxibs are comparable to tNSAIDs. There is an ongoing discussion about whether the slightly better GI tolerability (which is lost if acetylsalicylic acid is coadministered) of the coxibs is offset by their elevated risks for CV AEs (also seen with tNSAIDs other than naproxen), which apparently increase with dose and duration of exposure. In addition, the higher costs for coxibs (if compared to tNSAIDs, even when a "gastroprotective" proton pump inhibitor is coadministered) should be taken into consideration, if a coxib will be selected for certain patients with a high risk for GI complications. For such treatment, the lowest effective dose should be used for a limited time. Monitoring of kidney function and blood pressure appears advisable. It is hoped that further controlled studies can better define the therapeutic place of the coxibs.