Determinants of low serum concentrations of salicylates in patients with Kawasaki disease

Different dose aspirin plus immunoglobulin (DAPI) for prevention of coronary artery abnormalities in Kawasaki disease: Study protocol for a multi-center, prospective, randomized, open-label, blinded end-point, non-inferiority trial

BACKGROUND

Kawasaki disease is a pediatric acute systemic vasculitis that specifically involves the coronary arteries. Timely initiation of immunoglobulin plus aspirin is necessary for diminishing the incidence of coronary artery abnormalities (CAAs). The optimal dose of aspirin, however, remains controversial. The trial aims to evaluate if low-dose aspirin is noninferior to moderate-dose in reducing the risk of CAAs during the initial treatment of Kawasaki disease.

METHODS

This is a multi-center, prospective, randomized, open-label, blinded endpoint, noninferiority trial to be conducted in China. The planned study duration is from 2023 to 2026. Data will be analyzed according to intention-to-treat principles. Participants are children and adolescents under the age of 18 with Kawasaki disease, recruited from the inpatient units. A sample size of 1,346 participants will provide 80% power with a one-sided significance level of 0.025. Qualifying children will be randomized (1:1) to receive either intravenous immunoglobulin (2 g/kg) plus oral moderate-dose aspirin (30-50 mg·kg-1·d-1) until the patient is afebrile for at least 48 hours, or immunoglobulin plus low-dose aspirin (3-5 mg·kg-1·d-1) as initial treatment. The primary outcome will be the occurrence of CAAs at 8 weeks after immunoglobulin infusion. Independent blinded pediatric cardiologists will assess the primary endpoint using echocardiography.

CONCLUSIONS

There is a shortage of consensus on the dose of aspirin therapy for Kawasaki disease due to the lack of evidence. The results of our randomized trial will provide more concrete evidence for the efficacy and adverse events of low- or moderate-dose aspirin in the acute phase of Kawasaki disease.

TRIAL REGISTRATION

www.chictr.org.cn: ChiCTR2300072686.

Treatment of Kawasaki Disease: A Network Meta-Analysis of Four Dosage Regimens of Aspirin Combined With Recommended Intravenous Immunoglobulin

Aspirin was once believed to reduce the mortality of Kawasaki disease (KD) due to its effect on the thrombotic occlusion of coronary arteries. However, conflicting evidence has been found regarding aspirin treatment and its benefit in patients with acute KD. We compared the efficacy of different aspirin doses in acute KD. A literature search of PubMed, EMBASE, and Cochrane databases was conducted to identify studies comparing different doses of aspirin for acute KD. The primary outcome of interest was coronary artery lesions (CAL). We used random-effects network meta-analysis. Six retrospective studies, including 1944 patients receiving aspirin in doses of 0, 3-5, 30-50, or 80-100 mg/kg/day, were selected. The risks of CAL were not significantly different for the various doses of aspirin compared to the placebo: odds ratio (OR) was 1.10 [95% confidence interval (CI): 0.70-1.71] for patients with aspirin 3-5 mg/kg/day; OR = 1.23 (95% CI: 0.67-2.26) for aspirin 30-50 mg/kg/day, and OR = 1.59 (95% CI: 0.74, 3.421) for 80-100 mg/kg/day. The P-score ranged from 0.76 for placebo to 0.19 for aspirin 80-100 mg/kg/day. The different doses of aspirin exhibited no significant difference with regard to the efficacy of CAL or with the secondary outcomes of intravenous immunoglobulin resistance or hospital stays for acute KD. Therefore, we found that treatment without any aspirin is not inferior to other doses of aspirin and can also slightly reduce the risk of CAL.

Pharmacokinetic and tolerability assessment of a pediatric oral formulation of pentoxifylline in kawasaki disease

BACKGROUND

In infants and children, treatment of Kawasaki disease (KD) with high-dose intravenous immunoglobulin (IVIG) and acetylsalicylic acid ([ASA] aspirin) diminishes inflammatory response and reduces the risk for coronary artery abnormalities. However, patients with high serum concentrations of tumor necrosis factor (TNF)-alpha, which is associated with vascular damage, may develop coronary artery lesions even with treatment. The hemorheologic agent pentoxifylline blocks the production of TNF-alpha and may be an appropriate adjunctive therapy to IVIG and ASA.

OBJECTIVE

The objective of this study was to assess the pharmacokinetic characteristics and tolerability of a new oral syrup formulation of pentoxifylline as an adjunct to IVIG and ASA in the treatment of KD in children.

METHODS

Hospitalized boys and girls aged 6 months to 5 years and who were diagnosed with KD within the first 10 days of illness were eligible. Patients were assigned to 1 of 4 pentoxifylline treatment groups, by dose level (dose levels 1, 2, 3, and 4: 10, 15, 20, and 25 mg/kg daily, respectively, divided into 3 doses). Six plasma samples collected at the time the first dose was administered, and 4 samples collected after administration of the last dose on study day 6, were assessed by high-performance liquid chromatography using noncompartmental and 1-compartment pharmacokinetic analyses for pentoxifylline and its active metabolite (M-1). TNF-alpha levels on days 1 and 6 were assessed using electroimmunoassay.

RESULTS

Fourteen boys and 10 girls were enrolled. The mean age, body weight, and illness day at study entry were 34.5 months, 13.8 kg, and 6, respectively. Pentoxifylline exhibited nonlinear kinetic characteristics, with median area under the plasma concentration-time curve from time 0 to infinity(AUC0-∞) values of 622, 3428, 8416, and 10,347 ng/mL · h for dose levels 1 to 4, respectively, on study day 1. Pentoxifylline noncompartmental oral clearance and volume of distribution were significantly lower, and dose-normalized AUC0-∞ was significantly higher, for dose level 3 than dose level 1. M-1 parameters were not significantly different between dose levels. No accumulation of pentoxifylline or M-1 was noted. Fifteen of 24 patients (63%) reported mild to moderate adverse events that may or may not have been treatment related. Frequency and severity did not differ significantly between dose levels.

CONCLUSIONS

In the children in this study, pentoxifylline was well tolerated at the doses studied. No notable differences in clinical outcomes were observed between dose levels, and dose levels 3 and 4 (20 and 25 mg/kg daily, respectively) resulted in similar exposure to both pentoxifylline and M-1. Future efficacy and tolerability studies should use a daily dose of 20 mg/kg of pentoxifylline in acute KD.

Is high-dose aspirin necessary in the acute phase of kawasaki disease?

Background and Objectives

We sought to determine whether high-dose aspirin is necessary for the acute therapy of Kawasaki disease (KD) in the intravenous immunoglobulin (IVIG) era.

Subjects and Methods

Two groups of KD patients treated during the different periods were included. Study group (n=51, treated with IVIG without concomitant use of aspirin in the acute phase) was compared with control group (n=129, treated with IVIG plus high-dose aspirin) with regard to the response to IVIG, duration of fever after IVIG completion, time to C-reactive protein (CRP) <3 mg/dL, and the incidence of coronary artery lesions (CALs).

Results

There was no difference between the groups in age, sex, and duration of fever before treatment. Pre-IVIG laboratory measures also did not differ from each other. IVIG-resistant cases were 8 (15.7%) in study group and 22 (17.1%) in control group (p=1.000). Mean duration of fever after IVIG completion in IVIG-responsive patients was 13.3±13.5 hours in study group compared to 6.2±8.3 hours in control group (p=0.000). The mean time to decrease in CRP was 4.0±1.7 days in study group and 4.1±2.2 days in control group (p=0.828). There were 2 (3.9%) patients with CALs in study group and 10 (7.8%) in control group (p=0.514).

Conclusion

Although high-dose aspirin shortens the duration of fever, treatment without aspirin in the acute phase has no influence on the response to IVIG, resolution of inflammation, or the development of CALs. In the IVIG era, high-dose aspirin may provide little benefit to the treatment in the acute phase of KD.

Salicylate for the treatment of Kawasaki disease in children

BACKGROUND

Kawasaki disease is the most common cause of acquired heart disease in children in developed countries. The coronary arteries supplying the heart can be damaged in Kawasaki disease. The principal advantage of timely diagnosis is the potential to prevent this complication with early treatment. Salicylate (acetyl salicylate acid (ASA), aspirin) and intravenous immunoglobulin (IVIG) are widely used for this purpose. Salicylate is largely otherwise avoided in children because of concerns about serious side effects, particularly the risk of Reyes syndrome.

OBJECTIVES

The objective of this review was to evaluate the effectiveness of salicylate in treating and preventing cardiac consequences of Kawasaki disease in children.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Disease Group searched their trials register (last searched July 2006) and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched Issue 3, 2006). We searched MEDLINE (January 1966 to July 2006), EMBASE (January 1980 to July 2006), and CINAHL (1982 to July 2006), and reference list of articles. In addition we contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of salicylate to treat Kawasaki disease in children were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

We found one trial involving 102 children which was described as randomised, but it was not possible to confirm the method of treatment allocation. A second comparative study, possibly with a randomised treatment allocation, was also identified. The one randomised trial reported no association between the addition of ASA to IVIG treatment on the rate of coronary artery abnormalities at follow up, but with wide confidence limits. The second, possibly randomised trial did demonstrate a reduction in duration of fever with high dose ASA compared to low dose ASA, but was insufficiently powered to establish the effect on coronary artery abnormalities at follow up.

AUTHORS' CONCLUSIONS

Until good quality RCTs are carried out, there is insufficient evidence to indicate whether children with Kawasaki disease should continue to receive salicylate as part of their treatment regimen.

Pharmacological therapy for patients with Kawasaki disease

Kawasaki disease is a systemic vasculitis of unknown aetiology that has been reported worldwide since its initial description in Japanese children. The most significant sequelae of acute Kawasaki disease are related to the inflammation of small to medium sized arteries and, in particular, the development of coronary artery aneurysms. Because the aetiology is unknown, pharmacological therapy is nonspecific and directed towards modulation of the inflammatory response and inhibition of platelet activation with the aim of preventing coronary artery aneurysms. In the US, the recommended treatment for Kawasaki disease in the acute phase is a single, high dose of intravenous gammaglobulin (2 g/kg) and high dose aspirin (80 to 100 mg/kg/day). Use of this regimen has resulted in a significant decrease in the incidence of coronary artery abnormalities. Although the American Heart Association currently recommends high dose aspirin, moderate doses are used in Japan and the optimal dose of aspirin is not known. There has been renewed interest in the use of corticosteroids in the treatment of acute Kawasaki disease: however, their precise role remains unclear. Newer antiplatelet agents have also shown some promise in the treatment of patients with coronary artery aneurysms. Long term pharmacological therapy consists primarily of anticoagulation in patients with persistent coronary artery abnormalities. In this review, current recommendations for pharmacological therapy in Kawasaki disease are reviewed and some of the controversies in management of this disease, including management of patients who do not respond to initial therapy and the role of corticosteroids in the acute setting, are outlined.

Risks and benefits of nonsteroidal anti-inflammatory drugs in children: a comparison with paracetamol

Nonsteroidal anti-inflammatory drugs (NSAIDs) possess antipyretic, analgesic and anti-inflammatory effects. They are frequently used in children and have numerous therapeutic indications, the most common ones being fever, postoperative pain and inflammatory disorders, such as juvenile idiopathic arthritis (JIA) and Kawasaki disease. Their major mechanism of action is through inhibition of prostaglandin biosynthesis by blockade of cyclo-oxygenase (COX). The disposition of most NSAIDs has been mainly studied in infants > or = 2 years of age. Compared with adults, the volume of distribution and clearance of NSAIDs such as diclofenac, ibuprofen (infants aged between 3 months and 2.5 years), ketorolac and nimesulide were increased in children. The elimination half-life was similar in children to that in adults. These pharmacokinetic differences might be clinically significant with the need for higher loading and/or maintenance doses in children. Ibuprofen, acetylsalicylic acid (ASA) and acetaminophen are the most frequently used agents for fever reduction in children. Over the past 20 years, because of the association between ASA use and Reye's syndrome, most of the interest has been directed toward ibuprofen and acetaminophen. In view of its comparable antipyretic efficacy, but superior tolerability profile, acetaminophen, when used appropriately with age-adapted formulations, should remain the first-line therapy in the treatment of childhood fever. At the moment, there is no scientific evidence to recommend simultaneous use of these two antipyretic drugs. Most NSAIDs provide mild to moderate analgesia, with the exception of ketorolac which has a strong analgesic activity. The analgesic efficacy of ketorolac, ketoprofen, diclofenac and ibuprofen in the treatment of postoperative pain has been mainly studied following a single dose, in children of > or = 1 year of age undergoing minor surgeries. In this setting, when used either alone or in adjunct to caudal or epidural anaesthesia, they were associated with an opioid-sparing effect and were well tolerated. With the exception of ketorolac use in children undergoing tonsillectomy, where controversy exists regarding the risk of postoperative haemorrhage, NSAIDs have not been associated with an increased risk of perioperative bleeding. NSAIDs are the first-line therapy in JIA. They appear to be equally effective and tolerated, with the exception of ASA which is associated with more adverse effects. ASA has been used for many years in the treatment of Kawasaki disease and is part of the standard modality of treatment in combination with intravenous gammaglobulins. More recently, lung inflammation associated with cystic fibrosis (CF) has become a new target for NSAIDs. Despite promising preliminary results with ibuprofen, numerous questions need to be answered before this new strategy becomes part of the conventional treatment of patients with CF. In summary, NSAIDs are effective in reducing fever, alleviating pain and reducing inflammation in children, with a good tolerance profile. Pharmacokinetic studies are needed to characterise the disposition of NSAIDs in very young infants in order to use them rationally. To date, no studies have been published on the disposition, tolerability and efficacy of specific COX-2 inhibitors in children. Further clinical experience with these agents in adults is warranted before undergoing trials with specific COX-2 inhibitors in children.

Kawasaki syndrome

Kawasaki syndrome is a fascinating worldwide illness of young children. This acute self-limited vasculitis has become the most common cause of acquired heart disease in children in the United States and Japan. KS causes significant coronary artery disease that may lead to myocardial infarction and sudden death. Clinical and epidemiologic features of KS support an infectious cause, but the etiology remains unknown. Clearly, additional research on the cause of KS and its pathogenesis is needed urgently to allow for improved diagnosis; more specific therapy; and, ultimately, prevention of the disorder.

Kawasaki syndrome

Kawasaki syndrome (KS) is an acute, sometimes fatal vasculitis of young children. KS has replaced acute rheumatic fever as the most common cause of acquired heart disease in children in the United States. The illness is manifested by prolonged fever, conjunctival injection, enanthem, exanthem, erythema and swelling of the hands and feet, and cervical adenopathy. These acute features of illness are self-limiting, but coronary artery abnormalities occur in 20% of untreated patients. The etiology of the illness is unknown, but its clinical and epidemiologic features are most consistent with an infectious cause. Common cardiovascular manifestations of the illness include myocarditis, pericardial effusion, and coronary artery aneurysm formation. Treatment with intravenous gamma globulin (IVGG) and aspirin within the first 10 days of illness reduces the prevalence of coronary artery abnormalities from 20% in those treated with aspirin alone to 4%. Patients who develop coronary artery aneurysms, particularly those who develop giant coronary artery aneurysms, may suffer myocardial infarction secondary to thrombosis or stenosis in the abnormal vessel. Additional research to determine the cause of KS is urgently needed to allow for improved diagnosis, more specific therapy, and prevention of the disorder.

Treatment of Kawasaki disease using the intravenous aspirin anti-inflammatory effect of salicylate

Serum salicylate concentrations were measured in 60 patients with acute phase Kawasaki disease (KD), who were treated with intravenous aspirin (IVASP), to evaluate its anti-inflammatory effect in the treatment of KD. Patients with serum salicylate concentrations > or = 150 micrograms/ml showed shorter durations of fever (7.1 +/- 2.0 vs 10.4 +/- 6.6 days; P < 0.05), shorter durations of positive serum C-reactive protein (14.6 +/- 4.5 vs 22.3 +/- 10.6 days; P < 0.01) and lower incidences of coronary arterial involvements (0/10 vs 6/24; P < 0.05) than did patients with serum salicylate concentrations < 150 micrograms/ml. Significant linear correlations were recognized between daily IVASP dosage and serum salicylate concentrations (r = 0.73; P < 0.01), and between serum salicylate concentrations and serum free salicylate concentrations (r = 0.82; P < 0.01). These correlations did not differ between the presence and absence of coronary arterial involvements. Based on these findings we concluded that a beneficial anti-inflammatory effect in the treatment of KD is achieved when the serum salicylate concentration is > or = 150 micrograms/ml, and that such concentrations could be achieved by increasing the daily IVASP dosage to 100 mg/kg per day or more.

Salicylate treatment in Kawasaki disease: high dose or low dose?

Salicylate is the basic therapy for Kawasaki disease, however its optimal dose is controversial. We investigated the therapeutic efficacy of high dose (100 mg/kg per day, n = 30) versus low dose (30 mg/kg per day, n = 30) salicylate. Duration of fever, SGPT, serum salicylate, plasma thromboxane B2 (TxB2) and 6-keto-prostaglandin F1 alpha (PGF1 alpha) levels were compared before enrollment and on days 4, 7 and 14 of treatment. In the high dose group, duration of fever was significantly shorter than that of the low dose group (3.2 +/- 0.3 versus 5.4 +/- 0.8 days, P less than 0.05), however, SGPT levels were significantly elevated (157 +/- 34 versus 48 +/- 11 IU/1, P less than 0.05). No differences in the incidence of coronary artery lesions were observed (5/30 versus 7/30). Plasma TxB2 production was completely blocked in both groups, and plasma 6-keto-PGF1 alpha levels in the high dose group on day 14 was lower than that in the low dose group (39 +/- 8 versus 159 +/- 65 pg/ml, P less than 0.05). SGPT and plasma 6-keto-PGF1 alpha correlated with serum salicylate concentration. These data suggest that high dose salicylate therapy may be disadvantageous as anti-thrombotic therapy, and supports the notion that low dose therapy is safe in the acute stage of Kawasaki disease.

Decreased protein binding of salicylates in Kawasaki disease

Because patients with Kawasaki disease have low serum concentrations of salicylates despite high doses, and because the free (unbound) drug is responsible for the pharmacologic effects of salicylates, we assessed salicylate protein binding in patients with Kawasaki disease. During the acute phase of the disease, protein binding of salicylate in 36 children with Kawasaki disease was 73 +/- 12%, significantly lower than during the subacute phase (90.4 +/- 8.7%; p less than 0.0005). Mean serum albumin concentration was 29.2 +/- 6.4 gm/L during the acute phase and 36.7 +/- 7.8 gm/L during the subsequent subacute phase (p less than 0.005). Salicylate protein binding was affected independently by both serum albumin and total salicylate levels. During the acute phase of Kawasaki disease, children had an average twofold increase in free salicylate compared with normoalbuminemic control subjects. A nomogram has been devised to derive free salicylate levels from the known total salicylate and serum albumin concentrations.