Are the biologic and clinical effects of the COX-2-specific inhibitors an advance compared with the effects of traditional NSAIDs?

This has been an unusual year for the accumulation of evidence regarding the clinical effects of inhibition of cyclooxygenase (COX)-1 and COX-2. This article reviews the available data regarding the clinical effects of the new COX-2-specific inhibitors, and speculates about the importance of the data as they relate to the treatment of patients with chronic pain and/or inflammation.

Unresolved issues in the role of cyclooxygenase-2 in normal physiologic processes and disease

Originally suggested to function mainly in inflammatory situations, recent data have implied important roles for the cyclooxygenase-2 isoenzyme in reproductive biologic processes, renal and neurologic function, and the antithrombotic activities of endothelial cells. As cyclooxygenase-2-specific inhibitors have recently become available as analgesic and anti-inflammatory drugs, a comprehensive view of this rapidly evolving field is necessary to anticipate both the potential therapeutic benefits and toxic effects associated with these agents.

Osteoarthritis: a review

In 1994, the Centers for Disease Control and Prevention reported that by the year 2020, arthritis will have the largest increase in numbers of new patients of any disease in the United States. The term arthritis refers to many diseases, the most common of which is osteoarthritis (OA). OA affects at least 16 million Americans, most of whom are older than 60 years. The disease is usually defined using radiologic criteria. More than 80% of people older than 75 years are symptomatic of OA. Considering cost of diagnosis, therapy (nonpharmacologic, pharmacologic, and surgical), side effects of therapy, and lost productivity, it is one of the more expensive and debilitating diseases in the United States. Given the large numbers of patients and the expense of the disease, it is not surprising that the diagnosis and care of patients with OA have come under scrutiny. The following article will provide some background on the disease and discuss management approaches that view the patient as a whole.

Basic biology and clinical application of specific cyclooxygenase-2 inhibitors

In summary, COX-2 is a highly regulated gene product that catalyzes the local production of PGs in pathologic and physiologic situations (Figure 1). It is clear that COX-2 is the isoform responsible for production of the PGs that mediate inflammation, pain, and fever. However, the role for COX-2 in normal physiology is still being defined. Specific COX-2 inhibitors represent a significant conceptual advance in therapy for patients with arthritis. Although there is no expectation of superior efficacy, clinical trials suggest that efficacy will be comparable with that of nonselective NSAIDs. Clinical trials demonstrate the potential for clinically meaningful reductions in the incidence of the most serious GI complications found with nonselective NSAIDs, i.e., ulcer, perforation, and GI bleeding. Over the next several years, treatment of large numbers of patients with specific COX-2 inhibitors will help to define the biology of COX-2. The magnitude of this advance in the therapy of rheumatic diseases is yet to be accurately determined, but the development of specific COX-2 inhibitors may afford significant new treatment options for many patients.

Anti-inflammatory and upper gastrointestinal effects of celecoxib in rheumatoid arthritis: a randomized controlled trial

CONTEXT

In vitro studies have shown that celecoxib inhibits cyclooxygenase 2 (COX-2) but not COX-1, suggesting that this drug may have anti-inflammatory and analgesic activity without adverse upper gastrointestinal (GI) tract effects that result from COX-1 inhibition.

OBJECTIVE

To test whether celecoxib has efficacy as an anti-inflammatory and analgesic with reduced GI tract mucosal damage compared with conventional nonsteroidal anti-inflammatory drugs in patients with rheumatoid arthritis.

DESIGN

Randomized, multicenter, placebo-controlled, double-blind trial lasting 12 weeks, with follow-up at weeks 2, 6, and 12, from September 1996 thorugh February 1998.

SETTING

Seventy-nine clinical sites in the United States and Canada.

PATIENTS

A total of 1149 patients aged 18 years or older with symptomatic rheumatoid arthritis who met inclusion criteria were randomized; 688 (60%) of these completed the study.

INTERVENTIONS

Patients were randomized to receive celecoxib, 100 mg, 200 mg, or 400 mg twice per day (n = 240, 235, and 218, respectively); naproxen, 500 mg twice per day (n = 225); or placebo (n = 231).

MAIN OUTCOME MEASURES

Improvement in signs and symptoms of rheumatoid arthritis as assessed using standard measures of efficacy and GI tract safety as assessed by upper GI tract endoscopy before and after treatment, compared among treatment groups.

RESULTS

All dosages of celecoxib and naproxen significantly improved the signs and symptoms of arthritis compared with placebo. Maximal anti-inflammatory and analgesic activity was evident within 2 weeks of initiating treatment and was sustained throughout the 12 weeks. The incidence of endoscopically determined gastroduodenal ulcers in placebo-treated patients was 4 (4%) of 99, and the incidences across all dosages of celecoxib were not significantly different (P>.40): 9 (6%) of 148 with 100 mg twice per day, 6 (4%) of 145 with 200 mg twice per day, and 8 (6%) of 130 with 400 mg twice per day. In contrast, the incidence with naproxen was 36 (26%) of 137, significantly greater than either placebo or celecoxib (P<.001). The overall incidences of GI tract adverse effects were 19% for placebo; 28%, 25%, and 26% for celecoxib 100 mg, 200 mg, and 400 mg twice per day, respectively; and 31 % for naproxen.

CONCLUSION

In this study, all dosages of celecoxib were efficacious in the treatment of rheumatoid arthritis and did not affect COX-1 activity in the GI tract mucosa as evidenced by less frequent incidence of endoscopic ulcers compared with naproxen.

Arthritis: new agents herald more effective symptom management

For physicians and patients alike, managing the symptoms of rheumatoid and osteoarthritis is an ongoing challenge. Myriad therapies are available, although virtually all provide only temporary relief and produce side effects that interrupt long-term use. New disease-modifying antirheumatic drugs, biologic response modifiers, and cyclooxygenase inhibitors offer the promise of more effective, longer lasting symptom management and, in some cases, reduced side effects. The population of older persons affected by arthritis continues to grow. Increased familiarity with these new treatments will aid primary care physicians in helping older patients better manage their arthritis during the next decade.

Role and regulation of cyclooxygenase-2 during inflammation

Prostaglandins are formed from arachidonic acid by the action of cyclooxygenase (COX) and subsequent downstream synthetases. Recently, it has been found that there are two closely related forms of COX, which are now known as COX-1 and COX-2. Although both isoforms of this enzyme convert arachidonate to prostaglandins, there are significant differences in their distribution in the body and their roles in health and disease. The basis for these important differences lies in the genes for COX-1 and COX-2 and the regulation of these genes. COX-1, the predominantly constitutive form of the enzyme, is expressed throughout the body and provides certain homeostatic functions, such as maintaining normal gastric mucosa, influencing renal blood flow, and aiding in blood clotting by abetting platelet aggregation. In contrast, COX-2, the inducible form, is expressed in response to inflammatory and other physiologic stimuli and growth factors and is involved in the production of those prostaglandins that mediate pain and support the inflammatory process. All conventional nonsteroidal anti-inflammatory drugs (NSAIDs) nonspecifically inhibit both COX-1 and COX-2 at standard anti-inflammatory doses. The beneficial anti-inflammatory and analgesic effects occur through the inhibition of COX-2, but the gastrointestinal toxicities and the mild bleeding diathesis occur as a result of concurrent inhibition of COX-1. It is important that physicians fully understand the pharmacologic basis for the differential actions of NSAIDs when prescribing them for pain and inflammation. This understanding is also important so that physicians can critically evaluate the basis for, and the emerging data on, COX-2-specific inhibitors and their potential role in clinical medicine. Agents that would inhibit COX-2 while sparing COX-1 represent an attractive therapeutic development and could represent a major advance in the treatment of rheumatoid arthritis and osteoarthritis, as well as a diverse array of other conditions.

Viscosupplementation therapy with intra-articular hyaluronic acid. Fact or fantasy?

Pharmacologic therapy for osteoarthritis is presently only palliative and is based on the use of analgesic or anti-inflammatory agents. Simple analgesics, however, do not provide enough of an effect to satisfy the needs of many OA patients, and anti-inflammatory drugs that are currently available do not have favorable risk-to-benefit ratio in typical patients with OA. A need remains, therefore, for therapies that will be analgesic, appropriately anti-inflammatory when necessary, and that may favorably alter the natural history of the disease. The development of intra-articular hyaluronic acid (HA) supplementation was thought to fulfill these criteria. This therapy has been shown to modulate pain in OA of the knee and investigators have attempted to show that it have positive effects on articular cartilage biology. This article considers these claims for HA supplementation as an important therapy for the treatment of OA.

The evolution of arthritis antiinflammatory care: where are we today?

Nonsteroidal antiinflammatory drugs (NSAID) are among the most commonly used drugs. Due to age-related changes in the gastrointestinal (GI) mucosa, the elderly are at increased risk of NSAID-induced gastropathy. Known risk factors include age > 60 years, concomitant glucocorticoid therapy, history of peptic ulcer disease or GI bleeding, and presence of significant comorbid conditions. Combinations of these risk factors substantially increase the likelihood of the development of a serious GI event in patients taking NSAID. The pathogenesis of NSAID-induced GI mucosal injury involves depletion of prostaglandins. Prostaglandin analog misoprostol is effective in preventing NSAID-induced gastric and duodenal ulcers and serious ulcer complications. The single tablet formulation of diclofenac and misoprostol is for patients at high risk of developing GI toxicity. This agent has been shown to provide antiinflammatory and analgesic activity equivalent to that of diclofenac, but with a significantly reduced incidence of GI ulceration compared with traditional NSAID. The finding that there are two isoforms of the enzyme prostaglandin synthase or cyclooxygenase (COX) has led to the search for compounds that inhibit only the isoform associated with the development of inflammation (COX-2), while sparing the isoform involved in normal physiologic processes. All NSAID inhibit both isoforms. Compounds specific for COX-2 promise to provide potent antiinflammatory and analgesic effects without the toxicity of NSAID, as well as having potential applications in other medical conditions.

The classification of cyclooxygenase inhibitors

In summary, precise classification of COX inhibitors has important clinical implications for efficacy and toxicity. However, classification of these agents clinically is difficult because there are insufficient data to predict correlations between biochemical and pharmacologic properties and the clinical effect of a given agent. In any case, specific COX-2 inhibitors are expected to show antiinflammatory and analgesic activities equivalent to those of NSAID, as well as significant reductions in the incidence of the life threatening side effects (i.e., GI bleeding) associated with COX-1 inhibition. The advantages of preferential COX-2 inhibitors may be more subtle and therefore more difficult to verify in clinical trials.

Economic and gastrointestinal safety comparisons of etodolac, nabumetone, and oxaprozin from insurance claims data from patients with arthritis

This study was conducted to compare the effect of etodolac, nabumetone, and oxaprozin use on gastrointestinal (GI) safety and associated costs based on insurance claims information from practice settings. Data were obtained from a national claims database (MarketScan) for the years 1992 to 1994. The claims data of interest were for patients with arthritis who had used etodolac, nabumetone, or oxaprozin exclusively during a 9-month follow-up period (ONLY groups), or these drugs plus (PLUS groups) the other nonsteroidal anti-inflammatory drugs (NSAIDs) ibuprofen, naproxen, diclofenac, sulindac, piroxicam, ketoprofen, or indomethacin. For each group, we obtained information on the use of inpatient and outpatient services for GI-related events and the associated costs. All GI admissions were classified as NSAID-induced or possibly NSAID-induced events based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9 CM) codes. All outpatient upper GI ulcers or bleeding episodes were also identified by specific ICD-9 CM code. There were no significant between-group demographic differences. The proportions of patients with NSAID-induced and possibly NSAID-induced GI admissions were 0.1% and 0.4% for the etodolac-ONLY, 0.3% and 1.0% for the nabumetone-ONLY, and 0.1% and 0.5% for the oxaprozin-ONLY groups, respectively (P > 0.05), and a similar pattern was observed among the PLUS groups. In outpatient settings, 3.9%, 4.2%, and 4.9% of the etodolac-, nabumetone-, and oxaprozin-ONLY patients, respectively (P > 0.05), and 6.0%, 5.3%, and 4.7% of the etodolac-, nabumetone-, and oxaprozin-PLUS patients, respectively, had at least one upper GI ulcer/bleeding claim (P > 0.05). The total health care costs for 9 months were approximately $3000 each for the etodolac-, nabumetone-, and oxaprozin-ONLY groups. Oxaprozin, nabumetone, and etodolac had similar GI-safety and associated-costs profiles based on information from practice settings. Also, in patients who used multiple NSAIDs, the groups did not differ in their GI-safety and cost profiles.

Cyclooxygenase in biology and disease

Cyclooxygenase (COX), the key enzyme required for the conversion of arachidonic acid to prostaglandins was first identified over 20 years ago. Drugs, like aspirin, that inhibit cyclooxygenase activity have been available to the public for about 100 years. In the past decade, however, more progress has been made in understanding the role of cyclooxygenase enzymes in biology and disease than at any other time in history. Two cyclooxygenase isoforms have been identified and are referred to as COX-1 and COX-2. Under many circumstances the COX-1 enzyme is produced constitutively (i.e., gastric mucosa) whereas COX-2 is inducible (i.e., sites of inflammation). Here, we summarize the current understanding of the role of cyclooxygenase-1 and -2 in different physiological situations and disease processes ranging from inflammation to cancer. We have attempted to include all of the most relevant material in the field, but due to the rapid progress in this area of research we apologize that certain recent findings may have been left out.

Preliminary study of the safety and efficacy of SC-58635, a novel cyclooxygenase 2 inhibitor: efficacy and safety in two placebo-controlled trials in osteoarthritis and rheumatoid arthritis, and studies of gastrointestinal and platelet effects

OBJECTIVE

To investigate the efficacy and safety of SC-58635 (celecoxib), an antiinflammatory and analgesic agent that acts by selective cyclooxygenase 2 (COX-2) inhibition and is not expected to cause the typical gastrointestinal (GI), renal, and platelet-related side effects associated with inhibition of the COX-1 enzyme.

METHODS

Four phase II trials were performed: a 2-week osteoarthritis efficacy trial, a 4-week rheumatoid arthritis efficacy trial, a 1-week endoscopic study of GI mucosal effects, and a 1-week study of effects on platelet function.

RESULTS

The 2 arthritis trials identified SC-58635 dosage levels that were consistently effective in treating the signs and symptoms of arthritis and were distinguished from placebo on standard arthritis scales. In the upper GI endoscopy study, 19% of subjects receiving naproxen (6 of 32) developed gastric ulcers, whereas no ulcers occurred in subjects receiving SC-58635 or placebo. The study of platelet effects revealed no meaningful effect of SC-58635 on platelet aggregation or thromboxane B2 levels, whereas aspirin caused significant decreases in 2 of 3 platelet aggregation measures and thromboxane B2 levels. In all 4 trials, SC-58635 was well tolerated, with a safety profile similar to that of placebo.

CONCLUSION

SC-58635 achieves analgesic and antiinflammatory efficacy in arthritis through selective COX-2 inhibition, without showing any evidence of 2 of the toxic effects of COX-1 inhibition associated with nonsteroidal antiinflammatory drugs.

Biology and toxic effects of nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) continue to be important therapeutically. The development of drugs that are highly COX-2 selective has led to interesting new findings about their effects and potential toxic reactions. This year there were interesting observations about the effects of individual NSAIDs on the gastrointestinal mucosa, risk factors for sustaining an NSAID-induced gastric or duodenal ulcer, and there has been progress in further understanding what may or may not work to prevent a toxic reaction. Furthermore, information has been gathered about the effects of NSAIDs on colorectal polyps and the development of cancers.

Biologic effects of nonsteroidal anti-inflammatory drugs

The nonsteroidal antiinflammatory drugs (NSAIDs) continue to be important therapeutic interventions for the treatment of pain and inflammation. Investigators continue to produce new information about their biologic effects, including their actions as well as their toxic effects and methods to decrease the potential side effects associated with their use. This year many papers have been published speculating about those NSAIDs that are reported to selectively inhibit the isoform of the cyclooxygenase enzyme that is induced in inflammatory conditions (Cox-2) rather than that associated with normal physiologic function (Cox-1). Reports have shown that the more Cox-2-selective NSAIDs (from three- to 10-fold more selective for Cox-2 over Cox-1) seem to have less gastrointestinal toxicity associated with their use; however, little evidence has yet emerged from phase I, II, or III studies about the clinical effects of the highly selective Cox-2 inhibitors (300-fold or more selective for Cox-2 over Cox-1). In addition, intriguing animal studies have shown the effects of knockout of the genes controlling the activities of either Cox-1 or Cox-2 in mice.

NSAIDs and the elderly. Toxicity and economic implications

Despite their propensity to cause toxicity, nonsteroidal anti-inflammatory drugs (NSAIDs) are routinely prescribed for older patients for painful musculoskeletal conditions, many of which are noninflammatory in nature. In some settings, simple analgesia with paracetamol (acetaminophen) or tramadol may be just as effective as NSAIDs. The benefits of therapy with NSAIDs must be weighed against their potential risks. With the anticipated growth of the elderly population, the economic implications of NSAID use in older patients are staggering. Estimates of the total cost of prescribing NSAIDs to the elderly must include the additional costs of gastroprotective agents, prophylaxis, laboratory monitoring, physician evaluations and interventions for adverse effects. Misoprostol may be cost effective as primary prophylaxis of NSAID-induced ulcer disease in some elderly patients. NSAIDs may reduce disability and improve quality of life, thereby offsetting their costs. To date, the direct, indirect and intangible cost of NSAIDs and cost offsets have not been systematically evaluated in the elderly. At this juncture, NSAIDs may be used judiciously in older patients, and misoprostol should be considered in high risk patients. Further studies to assess the economics of NSAIDs in the elderly population are warranted.

Actions and toxicity of nonsteroidal anti-inflammatory drugs

Use of nonsteroidal anti-inflammatory drugs (NSAIDs) continues to be an important therapeutic intervention throughout the world for patients with pain and inflammation. The six major classes of NSAIDs (including the salicylates) bear the common property of inhibiting cyclooxygenase, the enzyme that catalyzes the synthesis of cyclic endoperoxides from arachidonic acid to yield prostaglandins. Anecdotal evidence has accumulated that the nonacetylated salicylates are as efficacious as the other NSAIDs, but there have been few controlled trials demonstrating that they are reasonable anti-inflammatory agents. This paper discusses the newest of the available clinical observations that nonacetylated salicylates are as efficacious as one of the newer NSAIDs in patients with rheumatoid arthritis. Because the nonacetylated salicylates are weak prostaglandin inhibitors, several other non-prostaglandin mediated mechanisms of action for the NSAIDs have been postulated and are described in this paper. In addition to papers describing NSAID effects on cartilage, this year several interesting papers described further effects of tenidap, a novel NSAID presently in development. Other papers reviewed attempts to develop NSAIDs with less severe gastrointestinal effects. Some reports discuss the use of topical NSAIDs, which are not clearly better than oral preparations. Data are also reviewed demonstrating that misoprostol effectively decreased significant poor gastrointestinal outcomes in patients who were treated with this NSAID for 6 months. New treatment regimens for decreasing misoprostol-induced toxicity are also reviewed. Finally, the effects of NSAID prophylaxis in preventing heterotopic bone formation in patients with osteoarthritis who undergo hip replacement surgery are noted.

A multicenter trial of recombinant human interferon gamma in patients with systemic sclerosis: effects on cutaneous fibrosis and interleukin 2 receptor levels

OBJECTIVE

To evaluate the acute toxicity, potential efficacy, and effects on the soluble interleukin 2 receptor (sIL-2R) of recombinant human interferon gamma (rIFN-gamma) in patients with systemic sclerosis (SSc).

METHODS

A multicentered, pilot clinical trial of rIFN-gamma was performed on 20 patients (15 women, 5 men, mean age 45 years) with active cutaneous SSc (mean disease duration 36 months) to evaluate it potential as a novel therapy for this untreatable disorder. After one week of rIFN-gamma 0.01 mg/m2/day, subjects self-administered rIFN-gamma 0.1 mg/m2/day intramuscularly for a total of 18 weeks. The major outcome variable was a modified skin score (0 = normal skin, 3 = hidebound skin) measured and summed from 15 anatomic areas of the body. sIL-2R levels were measured by ELISA at entry and exit from the study.

RESULTS

The clinical results were modest at best. Nine of 20 patients achieved at least a 20% reduction in skin score, with one patient showing almost total remission of all skin abnormalities. The mean skin score at entry for all subjects was 22.8 +/- 8.9 and over the course of the trial improved marginally compared to baseline (mean change -4.72 +/- 6.62; p = 0.008). However, 8 subjects did not change appreciably while in the trial. Antibodies to Scl-70 were observed in only 5 patients (all with diffuse scleroderma) and were not associated with either response to or complications from therapy. The adverse reactions were frequent and occasionally severe. Ten subjects were withdrawn because of exacerbation of Raynaud's symptoms (n = 5), constitutional symptoms (n = 2), development of renal crises (n = 2), and mild pancytopenia (n = 1). Minor laboratory abnormalities were common and included elevation of cholesterol, triglycerides, hepatic transaminases, and reduction in white blood cell count. Compared to controls, mean sIL-2R was markedly elevated at entry (1309 +/- 495 U/ml; p = 0.0001) and did not change appreciably at exit. Spearman correlation analysis showed a trend but no statistically significant association of skin score with sIL-2R (R = 0.408; p = 0.074). However, sIL-2R was significantly correlated with erythrocyte sedimentation rate (R = 0.542; p = 0.0165). A subset analysis revealed that skin score (p = 0.0001) and sIL-2R (p = 0.00170) were significantly higher at baseline for patients with diffuse scleroderma compared to patients with limited disease.

CONCLUSION

rIFN-gamma may be beneficial for some patients with SSc, but the benefit appears marginal for most individuals and the side effects frequent. Although sIL-2R was elevated in many of the patients with SSc, it did not appear to be correlated with activity of cutaneous disease or response to therapy.

Risk factors for serious nonsteroidal-induced gastrointestinal complications: regression analysis of the MUCOSA trial

OBJECTIVES

This analysis evaluated the clinical and demographic risk factors for a suspected, serious nonsteroidal anti-inflammatory drug (NSAID)-induced gastrointestinal (GI) complication in everyday clinical practice and calculated the risk reduction associated with misoprostol therapy in these "at-risk" patients.

METHODS

Using logistic regression analysis, the data set from a randomized, parallel, placebo-controlled trial of misoprostol in 8,843 rheumatoid arthritis patients taking NSAIDs (the Misoprostol Ulcer Complications Outcomes Safety Assessment trial) was modeled to identify risk factors for GI adverse events. The dependent variable was defined as a "suspected serious GI complication," and the independent variables included demographic features, level of functional disability, presence of co-morbid diseases, use of certain drugs, and treatment arm.

RESULTS

Two hundred forty-two suspected serious GI complications were observed; 102 occurred in the misoprostol treatment group (risk: 2.32%) and 140 in the placebo group (risk: 3.15%). Overall risk reduction due to misoprostol therapy was 26.6% (confidence interval 5.5%-42.9%, P < .05). However, in patient groups with identified risk factors, misoprostol use decreased the risk for an adverse GI event by 38.3%-87.3%. Specifically, those who benefitted significantly from therapy with misoprostol were patients with a history of peptic ulcer disease (risk reduction 52.4%), history of previous GI bleeding (risk reduction 50%), history of significant cardiovascular disease (risk reduction 38.3%), significant functional disability (risk reduction 87.2%), and patients whose symptoms required concomitant antacid use (risk reduction 48.3%).

CONCLUSION

We conclude that in everyday practice, patients who require chronic NSAID therapy and who have specific clinical risk factors may benefit from misoprostol co-therapy.

Quantification of inflammation in the wrist with gadolinium-enhanced MR imaging and PET with 2-[F-18]-fluoro-2-deoxy-D-glucose

PURPOSE

To quantify the activity of joint inflammation with magnetic resonance (MR) imaging and positron emission tomography (PET).

MATERIALS AND METHODS

Gadolinium-enhanced MR imaging and 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) PET of the wrist were performed prospectively in 12 patients receiving antiinflammatory therapy. Patients were studied three times: off medications for 2 weeks, after 2 weeks of treatment with prednisone or nonsteroid antiinflammatory drugs, and after 12 weeks of treatment with methotrexate. Volume of enhancing pannus (VEP) was determined from fat-suppressed MR images (12 patients). FDG uptake was calculated from PET images (11 patients).

RESULTS

VEP and FDG uptake were closely correlated (r > .86, P < .0001), as were changes in VEP and standardized uptake volume (r > .91, P < .0002). VEP and FDG uptake were strongly associated with clinical findings in wrists (P < .002) but not with treatment outcomes (P > .05).

CONCLUSION

Contrast material-enhanced MR imaging and PET allow quantification of volumetric and metabolic changes in joint inflammation and comparison of efficacies of antiinflammatory drugs.