Intravenous Cetirizine vs Intravenous Diphenhydramine for the Prevention of Hypersensitivity Infusion Reactions: Results of an Exploratory Phase 2 Study

Pretreatment with antihistamines for the prevention of hypersensitivity infusion reactions is recommended for certain biologics and chemotherapies. Cetirizine is the first injectable second-generation antihistamine recently approved for acute urticaria. A randomized, exploratory phase 2 study evaluated intravenous (IV) cetirizine 10 mg versus IV diphenhydramine 50 mg as pretreatment in patients receiving an anti-CD20 agent or paclitaxel. In the overall population (N = 34) and an elderly subgroup (n = 21), IV cetirizine was as effective as IV diphenhydramine in preventing infusion reactions (primary outcome) and associated with less sedation at all time points, a shorter infusion center stay, and fewer treatment-related adverse events.

Optimizing chair time in infusion centers using intravenous cetirizine premedication for the prevention of hypersensitivity infusion reactions

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Background: Oncology infusion centers are increasingly focused on improving operational efficiencies and patient satisfaction, while maintaining quality care. One key component is optimizing chair time, which has been especially important for patient safety during the COVID-19 pandemic to reduce risk of transmission. Many infusions require antihistamine premedication to reduce the risk of hypersensitivity infusion reactions (IRs). The two IV options are IV diphenhydramine and IV cetirizine, which have a quicker onset than oral options and can be administered IV push. In treating acute urticaria, IV cetirizine was shown to be comparable to IV diphenhydramine, with fewer side effects, and it may be effective for preventing IRs with improved chair time. Methods: A randomized, double-blind phase 2 study evaluating premedication with single dose IV cetirizine 10 mg versus IV diphenhydramine 50 mg was conducted in 34 patients receiving paclitaxel, rituximab, its biosimilar or obinutuzumab (first cycle, retreatment after 6 months or with persistent IRs). The primary objective was the incidence of IRs after premedication. Secondary endpoints included sedation due to antihistamines and time to readiness for discharge. Sedation was reported by patients on a scale of 0-4 (0 = none to 4 = extremely severe). No formal statistical analyses were planned given the exploratory nature of the study. Results: Adults primarily with cancer (n = 31 [91%]) were enrolled during the COVID-19 pandemic, from March 25 to November 23, 2020. The median age was 65 and 67 years in the IV cetirizine and diphenhydramine groups, respectively. The number of patients with IRs was 2/17 (11.8%) with IV cetirizine versus 3/17 (17.6%) with IV diphenhydramine. The mean sedation score in the IV cetirizine group compared to the IV diphenhydramine group was lower at all time points, including at discharge (0.1 vs 0.4, respectively). Mean time to discharge was 24 minutes less with IV cetirizine (4.3 hours [1.5]) versus IV diphenhydramine (4.7 hours [1.2]). This difference was greater (30 minutes less) in those ≥65 years of age (4.4 [1.3] vs 4.9 [1.0] hours). Regardless of whether patients received paclitaxel (n = 9) or an anti-CD20 (n = 25), patients had less chair time when premedicated with IV cetirizine. There were fewer treatment-related adverse events (AEs) with IV cetirizine (2 events) than with IV diphenhydramine (4 events). Conclusions: This was the first randomized, controlled trial evaluating IV antihistamine premedication for IRs and chair time. It was shown that IV cetirizine can prevent IRs, with less sedation, fewer related AEs and reduced chair time compared to IV diphenhydramine. This improves infusion center operations and patient experience. Clinical trial information: NCT04189588.

Effects of febuxostat versus allopurinol and placebo in reducing serum urate in subjects with hyperuricemia and gout: a 28-week, phase III, randomized, double-blind, parallel-group trial

OBJECTIVE

To compare the urate-lowering efficacy and safety of febuxostat, allopurinol, and placebo in a large group of subjects with hyperuricemia and gout, including persons with impaired renal function.

METHODS

Subjects (n = 1,072) with hyperuricemia (serum urate level > or = 8.0 mg/dl) and gout with normal or impaired (serum creatinine level >1.5 to < or = 2.0 mg/dl) renal function were randomized to receive once-daily febuxostat (80 mg, 120 mg, or 240 mg), allopurinol (300 or 100 mg, based on renal function), or placebo for 28 weeks.

RESULTS

Significantly (P < or = 0.05) higher percentages of subjects treated with febuxostat 80 mg (48%), 120 mg (65%), and 240 mg (69%) attained the primary end point of last 3 monthly serum urate levels <6.0 mg/dl compared with allopurinol (22%) and placebo (0%). A significantly (P < 0.05) higher percentage of subjects with impaired renal function treated with febuxostat 80 mg (4 [44%] of 9), 120 mg (5 [45%] of 11), and 240 mg (3 [60%] of 5) achieved the primary end point compared with those treated with 100 mg of allopurinol (0 [0%] of 10). Proportions of subjects experiencing any adverse event or serious adverse event were similar across groups, although diarrhea and dizziness were more frequent in the febuxostat 240 mg group. The primary reasons for withdrawal were similar across groups except for gout flares, which were more frequent with febuxostat than with allopurinol.

CONCLUSION

At all doses studied, febuxostat more effectively lowered and maintained serum urate levels <6.0 mg/dl than did allopurinol (300 or 100 mg) or placebo in subjects with hyperuricemia and gout, including those with mild to moderately impaired renal function.

Determinants of the clinical outcomes of gout during the first year of urate-lowering therapy

Clinical benefit early in urate-lowering treatment of gout is difficult to document. We examined data from 1,832 gouty subjects treated with either urate-lowering agents or placebo to identify determinants of gout flare incidence and tophus size during year 1 of treatment. Reductions from pretreatment serum urate levels influenced flare frequency and tophus size, but the effect of urate level on flare incidence was biphasic. Lower urate levels were associated with higher flare incidence early in treatment but lower incidence by one year. The complex relationship between urate-lowering and clinical outcome early in treatment has implications for both clinical and investigative approaches to urate-lowering management.

The effect of age and gender on pharmacokinetics, pharmacodynamics, and safety of febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase

Febuxostat is a novel nonpurine selective inhibitor of xanthine oxidase, which is currently being developed for the management of hyperuricemia in patients with gout. The effect of age and gender on the pharmacokinetics, pharmacodynamics, and safety of once-daily oral febuxostat 80 mg was assessed in healthy male and female subjects after 7 days. Following multiple dosing with febuxostat, there were no statistically significant differences in the plasma or urinary pharmacokinetic or pharmacodynamic parameters between subjects aged 18 to 40 years and >or=65 years. Although unbound peak concentration (C(max,u)) and area under the concentration-time curve (AUC(24,u)) for febuxostat were higher in women as compared with men (31.5 vs 23.6 ng/mL, P <or= .01, and 62.8 vs 53.9 ng x h/mL, P <or= .05, for C(max,u) and AUC(24,u), respectively), the differences were not considered clinically significant and could be largely accounted for by weight differences between male and female subjects. For pharmacodynamic parameters, even though the percentage decrease in serum uric acid 24-hour mean concentration was slightly greater in women than in men (59% vs 52%, P <or= .01), this difference was not considered clinically meaningful. Febuxostat was well tolerated in male and female subjects in both age groups. Age or gender had no clinically significant effect on the pharmacokinetics, pharmacodynamics, or safety of febuxostat. Therefore, febuxostat does not require any dose adjustments based on age or gender.

Effect of food or antacid on pharmacokinetics and pharmacodynamics of febuxostat in healthy subjects

What is already known about this subject. Febuxostat is a novel nonpurine selective inhibitor of xanthine oxidase. What this study adds. This is the first manuscript to address the effect of food and antacid on the pharmacokinetics and/or pharmacodynamics of febuxostat. The study will determine whether the drug can be administered regardless of food or antacid. It will therefore influence how the drug should be administered.

AIMS

To evaluate the effects of food or antacid on the pharmacokinetics and/or pharmacodynamics of febuxostat.

METHODS

Four Phase I, two-period, crossover studies were performed in healthy male and female subjects. Subjects either received single 40-mg (n = 24), multiple 80-mg (n = 24) and single 120-mg (n = 20) doses of febuxostat in fasting and nonfasting conditions, or received single 80-mg (n = 24) doses alone or with antacid.

RESULTS

Food caused a decrease in C(max) (38-49%) and AUC (16-19%) of febuxostat at different dose levels following single or multiple oral dosing with febuxostat. However, a slightly greater percent decrease in serum uric acid concentrations (58% vs. 51%) after multiple dosing with 80 mg of febuxostat under nonfasting conditions was observed, which was statistically (P < 0.05) but not clinically significant. Antacid caused a decrease in C(max) (32%), but had no effect on AUC of febuxostat. Febuxostat was safe and well tolerated in all studies.

CONCLUSIONS

Even though food caused a decrease in the rate and extent of absorption of febuxostat, this decrease was not associated with a clinically significant change in febuxostat pharmacodynamic effect. Despite a decrease in the absorption rate of febuxostat, antacid had no effect on the extent of febuxostat absorption. Therefore, febuxostat can be administered regardless of food or antacid intake.

The impact of gout on work absence and productivity

OBJECTIVE

The goal of this analysis was to evaluate the impact of gout, a painful inflammatory arthritis condition, on an employed population's health-related work absence and objectively measured productivity output.

METHODS

Payroll, demographic, medical, pharmaceutical, sick leave, short- and long-term disability, and workers' compensation data were collected from multiple large employers with employees widely dispersed across the United States. Data were collected during the time period of 2001 to 2004 from approximately 300,000 employees. Objective productivity output data were also available for a subset of employees (captured electronically in the form of units of work processed per person). T-tests and chi-square tests were used to compare demographic data. Two-stage multivariate regression models were used to compare annual work absence and at-work productivity between employees with and without gout, while controlling for group differences in demographics, salary, other work-related variables, and comorbidities (using the Charlson Comorbidity Index).

RESULTS

The annual prevalence of gout was 4.7 per 1000 employees from 2001 to 2004. Employees with gout had 4.56 more annual absence days for all categories of health-related work absence than those without gout. Objective productivity (units of work processed) results were only available for a small subsample of employees (86 with gout and 27,472 without gout). Employees with gout processed 3.51% fewer units per hour worked and 2.38% fewer units per year than employees without gout (nonsignificant at P = 0.49 and P = 0.78, respectively).

CONCLUSION

This study suggests that gout has a substantial impact on work absence and may also negatively impact productivity.

Outcome evaluations in gout

Methods to measure outcomes in gout still require consensus and validation. This Special Interest Group was assembled to identify domains of interest and is now evaluating a series of outcomes for features of acute gouty arthritis and chronic gout. To accomplish this, working groups have been formed and domains identified. Delphi methodology has been used to address gouty flares as an outcome of greatest interest. Studies addressing other outcome measures were reported at the OMERACT 8 meeting and validation has begun on some outcomes. There has been progress on developing a definition of a flare, and validating reproducibility of some chronic gout outcome measures in some domains, such as tophus size and patient perceptions. Use of these outcomes as well as a health-related quality of life measure are being studied in clinical trials. Pain on a Likert scale appears to be a valid outcome in acute gout. Final validation of these outcomes has not yet been achieved. In summary, the unique problems of evaluating outcomes in gout are finally being addressed. While no measures are available for use yet, an agenda has been developed.

Metabolic syndrome-related conditions among people with and without gout: prevalence and resource use

OBJECTIVE

A cohort of employees with gout were compared to those without to evaluate the differences in prevalence of disorders associated with metabolic syndrome (both those considered underlying and those associated with end-stage morbidity and mortality) as well as the cost of annual medical services (AMS) required for treatment of these conditions.

METHODS

Employees with gout were identified by International Classification of Diseases-9 (ICD-9) code during the calendar years of 2001-2004 and compared to propensity-score matched employees without gout using the Human Capital Management Services Research Reference Database. T-tests were then used to compare prevalence and average AMS of comorbid disorders defined from Agency for Healthcare and Research Quality (AHRQ) diagnostic categories.

RESULTS

'Hyperlipidemia', 'essential hypertension', and 'diabetes mellitus without complications' ranked in the top 10 categories of mean number of AMS for employees with gout using AHRQ specific categories; the values were higher than found for those without gout (all p < 0.0001). 'Essential hypertension', 'hyperlipidemia', 'diabetes mellitus without complications', and 'coronary atherosclerosis' showed an approximate 2:1 prevalence ratio for employees with gout over those without (p < or = 0.05). Main study limitations include the small number of subjects with gout, retrospective study design, and possible miscoding and/or non-coding of individuals with the studied disorders.

CONCLUSION

These results support the continued need for patients with gout and their clinicians to be aware of the possibility of the increased risk of associated metabolic syndrome and related comorbidities in these individuals, emphasizing the need for prevention when possible and treatment when necessary.

Pharmacokinetic interactions of concomitant administration of febuxostat and NSAIDs

To evaluate the effect of febuxostat on the pharmacokinetics of indomethacin and naproxen and vice versa, 2 multiple-dose, 3-period crossover studies were performed in healthy subjects. In study 1, subjects received febuxostat 80 mg once daily, indomethacin 50 mg twice daily, or both. In study 2, subjects received febuxostat 80 mg, naproxen 500 mg twice daily, or both. Twenty-four-hour blood samples were collected on day 5 in study 1 and day 7 in study 2. In study 1, 90% confidence intervals of geometric mean ratios for maximum plasma concentration (Cmax) and area under the curve (AUC) were within the 0.80 to 1.25 no-effect range for febuxostat and indomethacin. In study 2, 90% confidence intervals for febuxostat C(max) and AUC extended above that range, with increases of 28% and 40% in Cmax and AUC24, respectively. However, 90% confidence intervals for naproxen C(max) and AUC were within the 0.80 to 1.25 range. Febuxostat had no effect on the plasma pharmacokinetics of indomethacin and naproxen. Similarly, indomethacin had no effect on the plasma pharmacokinetics of febuxostat. Although naproxen caused an increase in plasma exposure to febuxostat, this increase is not expected to be clinically significant. Therefore, based on the plasma pharmacokinetic data in healthy subjects, febuxostat may be administered with indomethacin or naproxen with no dose adjustments for febuxostat, indomethacin, or naproxen.

Gout Assessment Questionnaire: Initial results of reliability, validity and responsiveness

We evaluated the psychometric properties of a new gout-specific patient reported outcomes questionnaire. The Gout Assessment Questionnaire (GAQ) and the SF-36 were administered to 126 subjects in a multicenter Phase II program of febuxostat, an investigational treatment for hyperuricemia (serum uric acid >8.0 mg/dl) in patients with chronic gout. The questionnaire was administered at baseline and 1, 6 and 12 months later. The majority of subjects, mean age 54 years, were male, Caucasian and had experienced a gout flare within the last year. Seven domains were identified, all met criteria for reliability and validity. Cronbach's alpha ranged from 0.78 to 0.97. Pearson correlations between GAQ and SF-36 scales were generally low to moderate, with the highest correlation between Gout Pain and Severity and SF-36 Bodily Pain, r = 0.45. Guyatt's statistic (measure of responsiveness) ranged from 0.24 to 1.00 at 12 months. Minimal clinically important differences ranged from 2 (Gout Concern) to 10 points (Productivity). The GAQ has acceptable psychometric properties. Further research is required to confirm results, which may provide more information to improve the GAQ for use in clinical trials.

Clinical trials in crystal arthropathy

A few clinical trials have evaluated therapeutic agents for crystal-associated arthropathy. Most of the studies are uncontrolled and observational. Management of patients who have acute crystal arthropathies usually is symptomatic with long-term management depending on crystal composition. In trials of gout, studies focus on acute symptomatic treatment, foregoing chronic management, which is aimed at reducing the concentration of serum urate. In those who have calcium crystals, however, there is no definitive or effective long-term treatment in chronic gout. The xanthine oxidase inhibitor and uricosurics are the agents used most commonly. Newer compounds in clinical trials show promise as effective and safe therapeutic options.

The economic burden of gout on an employed population

OBJECTIVE

To examine the economic burden of illness of gout in an employed population, quantifying the impact on employers annual health benefit costs for medical and prescription claims, sick leave, short- and long-term disability, and workers' compensation.

METHODS

Adjudicated claims data from 300000 employees from 2001 through 2004 were utilized. T-tests were used to compare demographic data and medical costs and services by Agency for Healthcare Research and Quality (AHRQ) diagnostic categories. Two-part models were used to determine average annual health benefit costs overall and medical costs by place of delivery. A risk stratification quintile analysis was also performed utilizing gout-specific medical and pharmaceutical costs.

RESULTS

There were 1171 employees with gout identified (total n = 249 038). All demographic variables between the two groups were statistically different (p <or= 0.05). The total annual cost for the employee with gout versus without gout was $6870 versus $3705, respectively, with significantly higher costs for medical claims, prescription claims, sick leave, short-term disability, and workers' compensation benefits. Costs were significantly higher by location of service for office, outpatient hospital or clinic, inpatient hospital, and laboratory. For the gout cohort, the top major diagnostic category in average cost was 'circulatory system' and in average services was 'endocrine, nutritional, metabolic, and immunologic systems'. Only 0.9% of employees with gout generated 20% of the total gout-specific medical and prescription costs.

CONCLUSION

Gout inflicts a substantial burden of illness upon employers in terms of medical and prescription costs, as well as other work-related benefits.

The effect of mild and moderate hepatic impairment on pharmacokinetics, pharmacodynamics, and safety of febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase

To assess the effect of hepatic impairment on the pharmacokinetics, pharmacodynamics, and safety of febuxostat at steady state, multiple once-daily 80-mg oral doses of febuxostat were administered to subjects with normal hepatic function and to subjects with mild or moderate hepatic impairment. There were no statistically significant differences in the plasma pharmacokinetic parameters for unbound febuxostat and its active metabolites between subjects with mild or moderate hepatic impairment and those with normal hepatic function. The percentage decrease in serum uric acid appeared to be lower in hepatic impairment groups (49% [mild] and 48% [moderate]) as compared to the normal hepatic group (62%). This lower percentage decrease was minimal and not considered clinically significant. Febuxostat 80 mg once daily appears to be generally safe and well tolerated in mildly and moderately impaired hepatic function groups, and dose adjustment is not required in subjects with mild to moderate hepatic impairment.

Magnetic resonance imaging in the quantitative assessment of gouty tophi

Measurements of tophus size can be important in monitoring the course of gout therapy, as tophus resolution is proposed as one measure of success of treatment. This multicentre study assessed the intra- and interreader reproducibility of quantitative tophus volume measurements from magnetic resonance images (MRI) in subjects with palpable gouty tophi. Subjects first underwent radiographic imaging of a selected tophus followed by MRI before and at <or=5, 10 and 20-min after gadolinium administration. After choosing optimal parameters, subjects underwent pre- and postgadolinium-enhanced MRIs of a selected tophus on two occasions separated by 5-10 days. Unenhanced spin-echo images provided satisfactory tophi images and were less subject to interfering artefacts than gadolinium-enhanced gradient-echo images. Intrareader reproducibility was excellent, with no statistically significant difference in mean tophus volume between visits (mean difference - 0.05 +/- 0.97 cm3). A small but statistically significant difference in interreader mean tophus volume was detected (mean difference 0.89 +/- 2.05 cm3; p < 0.05). MRI can quantify tophus size in gout and deserves further comparison with other techniques for tophus size monitoring in assessing effects of gout therapy.

Pharmacokinetics, Pharmacodynamics and Safety of Febuxostat, a Non-Purine Selective Inhibitor of Xanthine Oxidase, in a Dose Escalation Study in Healthy Subjects

BACKGROUND

Febuxostat is a novel non-purine selective inhibitor of xanthine oxidase currently being developed for the management of hyperuricemia in patients with gout.

OBJECTIVE

To investigate the pharmacokinetics, pharmacodynamics and safety of febuxostat over a range of oral doses in healthy subjects.

METHODS

In a phase I, dose-escalation study, febuxostat was studied in dose groups (10, 20, 30, 40, 50, 70, 90, 120, 160, 180 and 240 mg) of 12 subjects each (10 febuxostat plus 2 placebo). In all groups, subjects were confined for 17 days and were administered febuxostat once daily on day 1, and days 3-14. During the course of the study, blood and urine samples were collected to assess the pharmacokinetics of febuxostat and its metabolites, and its pharmacodynamic effects on uric acid, xanthine and hypoxanthine concentrations after both single and multiple dose administration. Safety measurements were also obtained during the study.

RESULTS

Orally administered febuxostat was rapidly absorbed with a median time to reach maximum plasma concentration following drug administration of 0.5-1.3 hours. The pharmacokinetics of febuxostat were not time dependent (day 14 vs day 1) and remained linear within the 10-120 mg dose range, with a mean apparent total clearance of 10-12 L/h and an apparent volume of distribution at steady state of 33-64 L. The harmonic mean elimination half-life of febuxostat ranged from 1.3 to 15.8 hours. The increase in the area under the plasma concentration-time curve of febuxostat at doses >120 mg appeared to be greater than dose proportional, while the febuxostat maximum plasma drug concentration was dose proportional across all the doses studied. Based on the urinary data, febuxostat appeared to be metabolised via glucuronidation (22-44% of the dose) and oxidation (2-8%) with only 1-6% of the dose being excreted unchanged via the kidneys. Febuxostat resulted in significant decreases in serum and urinary uric acid concentrations and increases in serum and urinary xanthine concentrations. The percentage decrease in serum uric acid concentrations ranged from 27% to 76% (net change: 1.34-3.88 mg/dL) for all doses and was dose linear for the 10-120 mg/day dosage range. The majority of adverse events were mild-to-moderate in intensity.

CONCLUSION

Febuxostat was well tolerated at once-daily doses of 10-240 mg. There appeared to be a linear pharmacokinetic and dose-response (percentage decrease in serum uric acid) relationship for febuxostat dosages within the 10-120 mg range. Febuxostat was extensively metabolised and renal function did not seem to play an important role in its elimination from the body.

Febuxostat compared with allopurinol in patients with hyperuricemia and gout

BACKGROUND

Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase, is a potential alternative to allopurinol for patients with hyperuricemia and gout.

METHODS

We randomly assigned 762 patients with gout and with serum urate concentrations of at least 8.0 mg per deciliter (480 micromol per liter) to receive either febuxostat (80 mg or 120 mg) or allopurinol (300 mg) once daily for 52 weeks; 760 received the study drug. Prophylaxis against gout flares with naproxen or colchicine was provided during weeks 1 through 8. The primary end point was a serum urate concentration of less than 6.0 mg per deciliter (360 micromol per liter) at the last three monthly measurements. The secondary end points included reduction in the incidence of gout flares and in tophus area.

RESULTS

The primary end point was reached in 53 percent of patients receiving 80 mg of febuxostat, 62 percent of those receiving 120 mg of febuxostat, and 21 percent of those receiving allopurinol (P<0.001 for the comparison of each febuxostat group with the allopurinol group). Although the incidence of gout flares diminished with continued treatment, the overall incidence during weeks 9 through 52 was similar in all groups: 64 percent of patients receiving 80 mg of febuxostat, 70 percent of those receiving 120 mg of febuxostat, and 64 percent of those receiving allopurinol (P=0.99 for 80 mg of febuxostat vs. allopurinol; P=0.23 for 120 mg of febuxostat vs. allopurinol). The median reduction in tophus area was 83 percent in patients receiving 80 mg of febuxostat and 66 percent in those receiving 120 mg of febuxostat, as compared with 50 percent in those receiving allopurinol (P=0.08 for 80 mg of febuxostat vs. allopurinol; P=0.16 for 120 mg of febuxostat vs. allopurinol). More patients in the high-dose febuxostat group than in the allopurinol group (P=0.003) or the low-dose febuxostat group discontinued the study. Four of the 507 patients in the two febuxostat groups (0.8 percent) and none of the 253 patients in the allopurinol group died; all deaths were from causes that the investigators (while still blinded to treatment) judged to be unrelated to the study drugs (P=0.31 for the comparison between the combined febuxostat groups and the allopurinol group).

CONCLUSIONS

Febuxostat, at a daily dose of 80 mg or 120 mg, was more effective than allopurinol at the commonly used fixed daily dose of 300 mg in lowering serum urate. Similar reductions in gout flares and tophus area occurred in all treatment groups.

Tophaceous gout: quantitative evaluation by direct physical measurement

OBJECTIVE

The absence of accepted standardized methods for monitoring tophaceous gout limits the ability to track tophus progression or regression. This multicenter study assessed intra- and interrater reproducibility of a simple and direct physical measurement.

METHODS

The quantitative evaluation was the area (mm2) of each measurable tophus and was determined independently by 2 raters on 2 occasions within 10 days. Intra- and interrater reproducibilities were determined by calculating mean differences and average percentage differences (APD) in measurements of areas for the same tophus at each of 2 visits and by each rater, respectively.

RESULTS

Fifty-two tophi were measured in 13 subjects: 22 on the hand/wrist, 16 on the elbow, and 14 on the foot/ankle. The mean (+/- SD) difference in tophus areas between visits was -0.2 +/- 835 mm2 (95% CI -162 to 162 mm2) and the mean (+/- SD) APD was 29% +/- 33%. The mean (+/- SD) APD between raters was 32% +/- 27%. The largest variations in measurements were noted for elbow tophi and variations were least for well demarcated tophi on the hands.

CONCLUSION

This simple and reproducible method can be easily utilized in clinical trials and in practice as a measure of efficacy of urate-lowering treatment in tophaceous gout. Among factors contributing to variability in these measurements were the anatomic site of tophi and rater experience with the method. Restriction of measurements to well circumscribed hand or foot tophi could improve reliability, but major changes, as expected with effective therapy, can clearly be documented with this simple technique.

Outcome measures for acute and chronic gout

Gout provides some unique challenges in classification and measurement of outcomes. Our aim was to evaluate criteria for classification and to develop and validate optimal instruments to measure outcomes for acute and chronic gout. A planning committee and interested attendees met to propose classification criteria and domains for outcomes. Seven of the current American Rheumatism Association preliminary criteria for classification were proposed as the best current criteria for acute gouty arthritis, pending further studies. The presence of gout is best established by crystal identification, although this technique has limitations. Five domains for acute gout outcomes and 9 for chronic gout were identified along with proposed instruments for testing and validation. The unique problems of gout evaluation can and will be addressed.

Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase: a twenty-eight-day, multicenter, phase II, randomized, double-blind, placebo-controlled, dose-response clinical trial examining safety and efficacy in patients with gout

OBJECTIVE

Gout affects approximately 1-2% of the American population. Current options for treating hyperuricemia in chronic gout are limited. The purpose of this study was to assess the safety and efficacy of febuxostat, a nonpurine selective inhibitor of xanthine oxidase, in establishing normal serum urate (sUA) concentrations in gout patients with hyperuricemia (>or=8.0 mg/dl).

METHODS

We conducted a phase II, randomized, double-blind, placebo-controlled trial in 153 patients (ages 23-80 years). Subjects received febuxostat (40 mg, 80 mg, 120 mg) or placebo once daily for 28 days and colchicine prophylaxis for 14 days prior to and 14 days after randomization. The primary end point was the proportion of subjects with sUA levels <6.0 mg/dl on day 28.

RESULTS

Greater proportions of febuxostat-treated patients than placebo-treated patients achieved an sUA level <6.0 mg/dl at each visit (P < 0.001 for each comparison). The targeted sUA level was attained on day 28 in 0% of those taking placebo and in 56% of those taking 40 mg, 76% taking 80 mg, and 94% taking 120 mg of febuxostat. The mean sUA reduction from baseline to day 28 was 2% in the placebo group and 37% in the 40-mg, 44% in the 80-mg, and 59% in the 120-mg febuxostat groups. Gout flares occurred with similar frequency in the placebo (37%) and 40-mg febuxostat (35%) groups and with increased frequency in the higher dosage febuxostat groups (43% taking 80 mg; 55% taking 120 mg). During colchicine prophylaxis, gout flares occurred less frequently (8-13%). Incidences of treatment-related adverse events were similar in the febuxostat and placebo groups.

CONCLUSION

Treatment with febuxostat resulted in a significant reduction of sUA levels at all dosages. Febuxostat therapy was safe and well tolerated.

Febuxostat (TMX-67), a novel, non-purine, selective inhibitor of xanthine oxidase, is safe and decreases serum urate in healthy volunteers

In order to evaluate the safety, pharmacological properties, and urate-lowering efficacy of febuxostat, a non-purine, selective inhibitor of xanthine oxidase, a Phase 1, 2-week, multiple-dose, placebo-controlled, dose-escalation study was conducted in 154 healthy adults of both sexes. Daily febuxostat doses in the range 10 mg to 120 mg resulted in proportional mean serum urate reductions ranging from 25% to 70% and in proportional increases in maximum febuxostat plasma concentrations and area under plasma concentration versus time curves. Accompanying the hypouricemic effect were increases in serum xanthine concentrations, decreases in urinary uric acid excretion, and increases in urinary xanthine and hypoxanthine excretion, confirming inhibition of xanthine oxidase activity by febuxostat. Hepatic conjugation and oxidative metabolism were the major pathways of elimination of febuxostat from the body, and renal elimination did not appear to play a significant role. Although not uncommon, adverse events were mild and self-limited, and no deaths or serious adverse events were observed. Febuxostat is a safe and potent hypouricemic agent in healthy humans.

Pharmacokinetics and Pharmacodynamics of Febuxostat, a New Non-purine Selective Inhibitor of Xanthine Oxidase in Subjects with Renal Impairment

To assess the safety, pharmacokinetics, and pharmacodynamics of febuxostat in subjects with normal renal function or renal impairment, febuxostat (80 mg/d) was orally administered for 7 days to subjects with normal renal function (n = 11, CLcr >80 mL/min/1.73 m) or to subjects with mild (n = 6, CLcr 50-80 mL/min/1.73 m), moderate (n = 7, CLcr 30-49 mL/min/1.73 m), or severe renal impairment (n = 7, CLcr 10-29 mL/min/1.73 m). The pharmacokinetics of febuxostat and its active quantifiable metabolites 67M-1, 67M-2, and 67M-4 as well as the pharmacodynamics of uric acid, xanthine, and hypoxanthine were determined in plasma (or serum) and urine. Febuxostat was safe and well tolerated. Regression analyses indicated that febuxostat tmax and Cmax,u values were not affected by CLcr. However, for AUC24,u, CLu/F, and t1/2z, regression analyses indicated a statistically significant relationship with CLcr. With the exception of 67M-1 Cmax, regression analyses for 67M-2 and 67M-4 Cmax, and for AUC24 for all 3 metabolites indicated a statistically significant linear relationship with CLcr. Irrespective of renal function group, the mean serum uric acid concentrations decreased by 55% to 64% by day 7. Although plasma exposure to febuxostat and its metabolites was generally higher in subjects with increasing degrees of renal impairment, the percentages of decrease in serum uric acid were comparable regardless of the renal function group. A once-daily 80-mg dose of febuxostat appears to be safe and well tolerated in different renal function groups and does not appear to require any dose adjustment based on differences in renal function.

Prevalence of Comorbid Conditions and Prescription Medication Use Among Patients With Gout and Hyperuricemia in a Managed Care Setting

BACKGROUND

: Comorbid disorders and multiple prescription drug use are common among patients with gout and/or hyperuricemia and may influence the clinical course and outcome of gout.

OBJECTIVE

: We wanted to document the conditions and associated medications in a large group of patients with gout in a managed care setting.

METHODS

: This study was a 2-year, retrospective, administrative claims analysis examining comorbid conditions and medication use among managed care enrollees with gout/hyperuricemia across the United States.

RESULTS

: Of the 9482 study subjects (82.1% men, mean age 52 years), 57.9% had hypertension, 45.3% had a lipid disorder, 32.5% had both conditions, and 19.9% had diabetes mellitus. During the 24-month follow-up period, subjects had 5 +/- 3.14 (mean +/- standard deviation) different comorbid conditions and filled prescriptions for of 11.0 +/- 7.90 different medications. The most commonly filled prescriptions included antihypertensive drugs, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins), and nonsteroidal antiinflammatory drugs (NSAIDs).

CONCLUSIONS

: The study indicates a high prevalence of both comorbid conditions and multiple medication use among managed care enrollees with gout and/or hyperuricemia. Heightened awareness of these associated disorders is important because they may warrant treatment of their own accord and often some modification of gout management. Drugs, particularly diuretics and prophylactic aspirin, could potentially contribute to the development of hyperuricemia and gout.

Increasing prevalence of gout and hyperuricemia over 10 years among older adults in a managed care population

OBJECTIVE

To determine whether the prevalence of gout and/or clinically significant hyperuricemia increased in a managed care population over 10 years.

METHODS

The study was a descriptive analysis utilizing an administrative claims database to ascertain 10-year trends in prevalence of gout and/or hyperuricemia. Prevalence rates were calculated cross-sectionally for each year (1990-99) and expressed/compared as rates per 1000 enrollees.

RESULTS

The prevalence of gout and/or hyperuricemia in the overall population increased by about 2 cases per 1000 enrollees over 10 years. In the > 75 year age group, rates increased from 21 per 1000 persons in 1990 to 41 per 1000 in 1999. In the 65-74 year age group, prevalence increased from between 21 and 24 per 1000 persons in the years 1990-92 to over 31 per 1000 during the years 1997-99. Prevalence rates in younger age groups (< 65 years) stayed consistently low during the years under study. There were sex differences in most age groups, with men having the greater burden of disease at every time point.

CONCLUSION

Prevalence of gout and/or hyperuricemia in the overall study population increased during the 10-year period. When stratified by age, there were increases in prevalence among groups over age 65 in both sexes. Although gout prevalence increased in both sexes over the 10-year period, men still had most of the burden of disease. In ages younger than 65, men had 4 times higher prevalence than women (4:1 ratio), but in the older age groups (> 65), the gender gap narrowed to 1 woman to every 3 men with gout and/or hyperuricemia (3:1 ratio).

Compliance with allopurinol therapy among managed care enrollees with gout: a retrospective analysis of administrative claims

OBJECTIVE

Poor compliance with gout medications has been recognized, but seldom studied. We investigated compliance with allopurinol among managed care enrollees suspected to have gout.

METHODS

This was a retrospective, administrative claims-based analysis of patients with gout. Compliance with allopurinol was measured using prescription-fill dates and days-supplied amounts. Compliance was defined for each prescription period as the presumed use of allopurinol on at least 80% of the days of that period.

RESULTS

Of 9482 patients identified, 65.9% filled at least one prescription for allopurinol during the 24 month followup period; 10.4% of allopurinol users filled one prescription and then discontinued use. Of the remaining patients, 13.7% never achieved compliance with therapy; 18% were compliant throughout the entire followup period. Patients were compliant with therapy for an average of 56% of their treatment periods and noncompliant for an average of 44%. In multivariate analysis, male sex was associated with decreased compliance (p < 0.01), although the effect was mitigated by increasing age. For subjects of both sexes, increasing age was associated with increased compliance (p < 0.05).

CONCLUSION

Compliance with allopurinol in this population was low. Because untreated gouty arthritis can lead to serious adverse outcomes (such as recurrent gouty arthritis, chronic gouty arthropathy, tophi, and urolithiasis) that are usually avoidable with antihyperuricemic therapy, efforts to achieve better compliance are warranted.