micafungin and Body-Weight

Micafungin is an echinocandin approved by the European Medicines Evaluation Agency for the treatment of invasive candidiasis in children, including premature infants born before 29 weeks of pregnancy, and as prophylaxis in children undergoing hematopoietic stem-cell transplantation or patients at risk of prolonged neutropenia. This drug has good activity in several Candida spp., including those resistant to fluconazole. Although micafungin is active against Aspergillus spp., it has been used mainly in combination therapy for invasive aspergillosis. There is ample information on the use of micafungin in children, including neonates, and this drug is the only echinocandin approved for use in infants aged less than 3 months. The efficacy, pharmacokinetics and safety of micafungin have been evaluated in phase II and III clinical trials in children, in which its efficacy and safety were demonstrated in comparison with liposomal amphotericin B and fluconazole. The pharmacokinetic profile of micafungin in children allows once daily intravenous administration, with greater clearance than in adults, and consequently pediatric doses are relatively higher. The most appropriate dose in children weighing less than 40 kg is 2 mg/kg/day in the treatment of invasive candidiasis and 1 mg/kg/day as prophylaxis in children undergoing hematopoietic stem-cell transplantation. Doses in neonates should be higher. In premature infants, the most appropriate doses to achieve levels in the brain parenchyma are 7 mg/kg/day and 10 mg/kg/day in those weighing more and less than 1,000 g, respectively. Micafungin has few drug-drug interactions and an acceptable safety profile. Withdrawal of this drug due to adverse effects is rare, although transaminase monitoring is recommended during treatment, as well as evaluation of the risk-benefit balance in patients with liver disease or concomitant administration of hepatotoxic drugs.

Topics: Adolescent; Adult; Age Factors; Animals; Antifungal Agents; Blood-Brain Barrier; Body Weight; Child; Child, Preschool; Clinical Trials as Topic; Double-Blind Method; Drug Approval; Drug Evaluation, Preclinical; Echinocandins; Humans; Infant; Infant, Newborn; Infant, Premature; Infant, Premature, Diseases; Lipopeptides; Meta-Analysis as Topic; Micafungin; Multicenter Studies as Topic; Mycoses; Rabbits; Randomized Controlled Trials as Topic

Micafungin is an echinocandin with proven efficacy against a broad range of fungal infections, including those caused by Candida spp.. To evaluate the safety and pharmacokinetics of once-daily 3 mg/kg and 4.5 mg/kg micafungin in children with proven, probable or suspected invasive candidiasis.. Micafungin safety and pharmacokinetics were assessed in 2 phase I, open-label, repeat-dose trials. In Study 2101, children aged 2-16 years were grouped by weight to receive 3 mg/kg (≥25 kg) or 4.5 mg/kg (<25 kg) intravenous micafungin for 10-14 days. In Study 2102, children aged 4 months to <2 years received 4.5 mg/kg micafungin. Study protocols were otherwise identical.. Safety was analyzed in 78 and 9 children in Studies 2101 and 2102, respectively. Although adverse events (AEs) were experienced by most children (2101: n=62; 2102: n=9), micafungin-related AEs were less common (2101: n=28; 2102: n=1), and the number of patients discontinuing due to AEs was low (2101: n=4; 2102: n=1). The most common micafungin-related AEs were infusion-associated symptoms, pyrexia and hypomagnesemia (Study 2101), and liver function abnormalities (Study 2102). The micafungin pharmacokinetic profile was similar to that seen in other studies conducted in children, but different than that observed in adults.. In this small cohort of children, once-daily doses of 3 mg/kg and 4.5 mg/kg micafungin were well tolerated. Pharmacokinetic data will be combined in a population pharmacokinetic analysis to support US dosing recommendations in children.

Topics: Adolescent; Antifungal Agents; Body Weight; Candidiasis, Invasive; Child; Child, Preschool; Drug Administration Schedule; Echinocandins; Female; Humans; Infant; Kidney Function Tests; Lipopeptides; Liver Function Tests; Male; Micafungin

The majority of Americans are overweight, and the incidence of obesity continues to increase. This trend predisposes people to a number of deleterious consequences, including the metabolic syndrome and other conditions that lead to a greater number of hospital admissions. Invasive candidiasis is an important nosocomial infection that results from these admissions. Echinocandins such as micafungin are indicated for treatment. We have previously demonstrated that overweight patients exhibit higher micafungin systemic clearance (SCL) than leaner patients. We hypothesized that obese and extremely obese people would show even higher SCL than merely overweight patients. To test this, we performed a prospective study of 36 adult volunteers randomized to receive a single dose of either 100 mg or 300 mg of micafungin whose body mass index fell within one of the following categories: <25, 25 to 40, and >40 kg/m(2). The male-to-female ratio was 1:1. The minimum weight was 43 kg, the median 97 kg, and the maximum weight 155 kg. A two-compartment model was examined using the maximum likelihood solution via the expectation-maximization algorithm. Men had a higher median SCL of 1.53 liters/h versus 1.29 liters/h (P = 0.01) in the Mann-Whitney U-test. The typical SCL was 1.04 liters/h but increased by a factor of (weight/66)(0.75) as weight increased above 66 kg. Thus, the relationship between micafungin SCL and weight in adults is best described by fractal-geometry-based laws. Furthermore, micafungin SCL continues to increase as weight increases, with no obvious plateau. This leads to a requirement for strategies to determine individualized dosing levels for obese and extremely obese patients.

Topics: Adult; Antifungal Agents; Body Mass Index; Body Weight; Echinocandins; Female; Humans; Lipopeptides; Male; Micafungin; Middle Aged; Obesity; Overweight; Young Adult

The object of this analysis was to develop a population pharmacokinetic model of micafungin, a new anti-fungal agent of the echinocandin class, to optimize dosing in Japanese patients with fungal infections. Population pharmacokinetics parameters were determined using NONMEM based on pharmacokinetic data from 198 subjects in seven clinical studies, comprising four phase I, two phase II and one pediatric phase III study. The healthy subjects received intravenous infusion of 2.5-150 mg micafungin. Adult and pediatric patients, age range of 8 month to 15 yeras old, were received 25-150 mg and 1-6 mg/kg daily, respectively. A total of 1825 micafungin plasma samples were available for this analysis. Two-compartment pharmacokinetic model was adopted. The clearance of micafungin was influenced by body weight in children and platelet counts (PLT). However the PLT accounted for less than 20% of the variation of micafungin clearance in Japanese subjects. In conclusions, body weight is the primary covariate factor in pediatric patients. The dose adjustment by body weight would be required only pediatric patients for the micafungin therapy in Japanese patients with fungal infection.

Topics: Adult; Antifungal Agents; Asian People; Bayes Theorem; Body Weight; Child; Echinocandins; Humans; Japan; Lipopeptides; Lipoproteins; Male; Micafungin; Middle Aged; Models, Biological; Mycoses; Peptides, Cyclic; Time Factors

We performed population pharmacokinetic analysis of micafungin in adult patients treated with doses between 12.5 and 200 mg/day. Our analysis identified a breakpoint patient weight of 66.3 kg above which serum clearance increased by approximately 50%. Patients with weight >66.3 kg may need larger doses to achieve similar exposures to those <66.3 kg. However, the clinical implications are still unknown.

Topics: Adolescent; Adult; Body Weight; Echinocandins; Female; Humans; Lipopeptides; Lipoproteins; Male; Metabolic Clearance Rate; Micafungin; Middle Aged; Serum