Genistein improves renal disease in a mouse model of nephropathic cystinosis: a comparison study with cysteamine.

Cysteamine is currently the only therapy for nephropathic cystinosis. It significantly improves life expectancy and delays progression to end-stage kidney disease; however, it cannot prevent it. Unfortunately, compliance to therapy is often weak, particularly during adolescence. Therefore, finding better treatments is a priority in the field of cystinosis. Previously, we found that genistein, an isoflavone particularly enriched in soy, can revert part of the cystinotic cellular phenotype that is not sensitive to cysteamine in vitro. To test the effects of genistein in vivo, we fed 2-month-old wild-type and Ctns-/- female mice with either a control diet, a genistein-containing diet or a cysteamine-containing diet for 14 months. Genistein (160 mg/kg/day) did not affect the growth of the mice or hepatic functionality. Compared with untreated mice at 16 months, Ctns-/- mice fed with genistein had lower cystine concentrations in their kidneys, reduced formation of cystine crystals, a smaller number of LAMP1-positive structures and an overall better-preserved parenchymal architecture. Cysteamine (400 mg/kg/day) was efficient in reverting the lysosomal phenotype and in preventing the development of renal lesions. These preclinical data indicate that genistein ameliorates kidney injury resulting from cystinosis with no side effects. Genistein therapy represents a potential treatment to improve the outcome for patients with cystinosis.

MFSD12 depletion reduces cystine accumulation without improvement in proximal tubular function in experimental models for cystinosis.

Cystinosis is an autosomal recessive lysosomal storage disorder, caused by mutations in the CTNS gene, resulting in an absent or altered cystinosin (CTNS) protein. Cystinosin exports cystine out of the lysosome, with a malfunction resulting in cystine accumulation and a defect in other cystinosin-mediated pathways. Cystinosis is a systemic disease, but the kidneys are the first and most severely affected organs. In the kidney, the disease initially manifests as a generalized dysfunction in the proximal tubules (also called renal Fanconi syndrome). MFSD12 is a lysosomal cysteine importer that directly affects the cystine levels in melanoma cells, HEK293T cells, and cystinosis patient-derived fibroblasts. In this study, we aimed to evaluate MFSD12 mRNA levels in cystinosis patient-derived proximal tubular epithelial cells (ciPTECs) and to study the effect of MFSD12 knockout on cystine levels. We showed similar MFSD12 mRNA expression in patient-derived ciPTECs in comparison with the control cells. CRISPR MFSD12 knockout in a patient-derived ciPTEC (CTNSΔ57kb) resulted in significantly reduced cystine levels. Furthermore, we evaluated proximal tubular reabsorption after injection of mfsd12a translation-blocking morpholino (TB MO) in a ctns-/- zebrafish model. This resulted in decreased cystine levels but caused a concentration-dependent increase in embryo dysmorphism. Furthermore, the mfsd12a TB MO injection did not improve proximal tubular reabsorption or megalin expression. In conclusion, MFSD12 mRNA depletion reduced cystine levels in both tested models without improvement of the proximal tubular function in the ctns-/- zebrafish embryo. In addition, the apparent toxicity of higher mfsd12a TB MO concentrations on the zebrafish development warrants further evaluation.NEW & NOTEWORTHY In this study, we show that MFSD12 depletion with either CRISPR/Cas9-mediated gene editing or a translation-blocking morpholino significantly reduced cystine levels in cystinosis ciPTECs and ctns-/- zebrafish embryos, respectively. However, we observed no improvement in the proximal tubular reabsorption of dextran in the ctns-/- zebrafish embryos injected with mfsd12a translation-blocking morpholino. Furthermore, a negative effect of the mfsd12a morpholino on the zebrafish development warrants further investigation.

Improved biochemical and neurodevelopmental profiles with high-dose hydroxocobalamin therapy in cobalamin C defect.

Cobalamin C (Cbl-C) defect causes methylmalonic acidemia, homocystinuria, intellectual disability and visual impairment, despite treatment adherence. While international guidelines recommend parenteral hydroxocobalamin (OH-Cbl) as effective treatment, dose adjustments remain unclear. We assessed OH-Cbl therapy impact on biochemical, neurocognitive and visual outcomes in early-onset Cbl-C patients treated with different OH-Cbl doses over 3 years. Group A (n = 5), diagnosed via newborn screening (NBS), received high-dose OH-Cbl (median 0.55 mg/kg/day); Group B1 (n = 3), NBS-diagnosed, received low-dose OH-Cbl (median 0.09 mg/kg/day); Group B2 (n = 12), diagnosed on clinical bases, received low-dose OH-Cbl (median 0.06 mg/kg/day). Biochemical analyses revealed better values of homocysteine, methionine and methylmalonic acid in Group A compared to Group B1 (p < 0.01, p < 0.05 and p < 0.01, respectively) and B2 (p < 0.001, p < 0.01 and p < 0.001, respectively). Neurodevelopmental assessment showed better outcome in Group A compared to low-dose treated Groups B1 and B2, especially in Developmental Quotient, Hearing and Speech and Performance subscales without significant differences between Group B2 and Group B1. Maculopathy was detected in 100%, 66% and 83% of patients in the three groups, respectively. This study showed that "high-dose" OH-Cbl treatment in NBS-diagnosed children with severe early-onset Cbl-C defect led to a significant improvement in the metabolic profile and in neurocognitive outcome, compared to age-matched patients treated with a "low-dose" regimen. Effects on maculopathy seem unaffected by OH-Cbl dosage. Our findings, although observed in a limited number of patients, may contribute to improve the long-term outcome of Cbl-C patients.

Neurologic outcome following liver transplantation for methylmalonic aciduria.

Liver and liver/kidney transplantation are increasingly used in methylmalonic aciduria, but little is known on their impact on CNS. The effect of transplantation on neurological outcome was prospectively assessed in six patients pre- and post-transplant by clinical evaluation and by measuring disease biomarkers in plasma and CSF, in combination with psychometric tests and brain MRI studies. Primary (methylmalonic- and methylcitric acid) and secondary biomarkers (glycine and glutamine) significantly improved in plasma, while they remained unchanged in CSF. Differently, biomarkers of mitochondrial dysfunction (lactate, alanine, and related ratios) significantly decreased in CSF. Neurocognitive evaluation documented significant higher post-transplant developmental/cognitive scores and maturation of executive functions corresponding to improvement of brain atrophy, cortical thickness, and white matter maturation indexes at MRI. Three patients presented post-transplantation reversible neurological events, which were differentiated, by means of biochemical and neuroradiological evaluations, into calcineurin inhibitor-induced neurotoxicity and metabolic stroke-like episode. Our study shows that transplantation has a beneficial impact on neurological outcome in methylmalonic aciduria. Early transplantation is recommended due to the high risk of long-term complications, high disease burden, and low quality of life.

The diagnostic challenge of mild citrulline elevation at newborn screening.

Citrulline is a target analyte measured at expanded newborn screening (NBS) and its elevation represents a biomarker for distal urea cycle disorders and citrin deficiency. Altered ratios of citrulline with other urea cycle-related amino acids are helpful for the differential diagnosis. However, the use of cut-off values in screening programmes has raised the issue about the interpretation of mild elevation of citrulline levels detected at NBS, below the usual range observed in the "classical/severe" forms of distal urea cycle disorders and in citrin deficiency. Herein, we report ten subjects with positive NBS for a mild elevation of citrulline (<100 µmol/L), in whom molecular investigations revealed carriers status for argininosuccinate synthase deficiency, a milder form of argininosuccinate lyase deficiency and two other diseases, lysinuric protein intolerance and dihydrolipoamide dehydrogenase deficiency, not primarily affecting the urea cycle. To guide the diagnostic process, we have designed an algorithm for mild citrulline elevation (<100 µmol/L) at NBS, which expands the list of disorders to be included in the differential diagnosis.

High-Dose Micafungin in Neonates and Young Infants with Invasive Candidiasis: Results of a Phase 2 Study.

Limited data are available on the most appropriate dosing, efficacy, and safety of micafungin in neonates and young infants with invasive candidiasis (IC). This study evaluated plasma levels, efficacy, and safety of micafungin at a dose of 8 mg/kg daily for a mean of 13.3 days (±5.2 days) in 35 neonates and young infants with IC. Micafungin plasma concentrations were 5.70 mg/liter preadministration and 17.23, 15.59, and 10.27 mg/liter after 1, 2, and 8 h, respectively. The resolution of the infection was achieved in 86.7% of patients treated for ≥14 days. In 20.0% of patients, we observed a transient hypertransaminasemia. Micafungin at a dose of 8 mg/kg daily is effective and well tolerated in neonates and young infants with IC. (This study has been registered at ClinicalTrials.gov under identifier NCT03421002 and in the EU Clinical Trials Register under number 2014-003087-20.).

Cell-Based Phenotypic Drug Screening Identifies Luteolin as Candidate Therapeutic for Nephropathic Cystinosis.

BACKGROUND: Mutations in the gene that encodes the lysosomal cystine transporter cystinosin cause the lysosomal storage disease cystinosis. Defective cystine transport leads to intralysosomal accumulation and crystallization of cystine. The most severe phenotype, nephropathic cystinosis, manifests during the first months of life, as renal Fanconi syndrome. The cystine-depleting agent cysteamine significantly delays symptoms, but it cannot prevent progression to ESKD and does not treat Fanconi syndrome. This suggests the involvement of pathways in nephropathic cystinosis that are unrelated to lysosomal cystine accumulation. Recent data indicate that one such potential pathway, lysosome-mediated degradation of autophagy cargoes, is compromised in cystinosis. METHODS: To identify drugs that reduce levels of the autophagy-related protein p62/SQSTM1 in cystinotic proximal tubular epithelial cells, we performed a high-throughput screening on the basis of an in-cell ELISA assay. We then tested a promising candidate in cells derived from patients with, and mouse models of, cystinosis, and in preclinical studies in cystinotic zebrafish. RESULTS: Of 46 compounds identified as reducing p62/SQSTM1 levels in cystinotic cells, we selected luteolin on the basis of its efficacy, safety profile, and similarity to genistein, which we previously showed to ameliorate other lysosomal abnormalities of cystinotic cells. Our data show that luteolin improves the autophagy-lysosome degradative pathway, is a powerful antioxidant, and has antiapoptotic properties. Moreover, luteolin stimulates endocytosis and improves the expression of the endocytic receptor megalin. CONCLUSIONS: Our data show that luteolin improves defective pathways of cystinosis and has a good safety profile, and thus has potential as a treatment for nephropathic cystinosis and other renal lysosomal storage diseases.

Renal and Extra Renal Manifestations in Adult Zebrafish Model of Cystinosis.

Cystinosis is a rare, incurable, autosomal recessive disease caused by mutations in the CTNS gene. This gene encodes the lysosomal cystine transporter cystinosin, leading to lysosomal cystine accumulation in all cells of the body, with kidneys being the first affected organs. The current treatment with cysteamine decreases cystine accumulation, but does not reverse the proximal tubular dysfunction, glomerular injury or loss of renal function. In our previous study, we have developed a zebrafish model of cystinosis through a nonsense mutation in the CTNS gene and have shown that zebrafish larvae recapitulate the kidney phenotype described in humans. In the current study, we characterized the adult cystinosis zebrafish model and evaluated the long-term effects of the disease on kidney and extra renal organs through biochemical, histological, fertility and locomotor activity studies. We found that the adult cystinosis zebrafish presents cystine accumulation in various organs, altered kidney morphology, impaired skin pigmentation, decreased fertility, altered locomotor activity and ocular anomalies. Overall, our data indicate that the adult cystinosis zebrafish model reproduces several human phenotypes of cystinosis and may be useful for studying pathophysiology and long-term effects of novel therapies.

A new HPLC-DAD method for contemporary quantification of 10 antibiotics for therapeutic drug monitoring of critically ill pediatric patients.

The common practice of therapeutic drug monitoring (TDM) involves the quantification of drug plasma concentrations at a specific time in a dosing window. Although TDM for antibiotics is not considered mandatory, it may represent a valid tool for clinicians in order to limit antibiotic resistance and avoid therapeutic failures. The aim of our study was to develop and validate a high-performance liquid chromatography-diode array detection method for simultaneous quantification of 10 antibiotics in plasma. This method has a fast analytical procedure that uses the same chromatographic conditions to quantify ceftazidime, ceftriaxone, meropenem, ertapenem, ciprofloxacin, tigecycline, ampicillin, levofloxacin and piperacillin, plus the ß-lactamase inhibitor tazobactam. Method validation was ensured by testing selectivity, accuracy, precision, limits of detection and quantification, recovery and stability. The calibration ranges, established accordingly to the expected plasma concentration in patients, showed a coefficient of determination >0.996 for all compounds. Within- and between-days precisions reported a coefficient of variation >15%. Similarly, the accuracy evaluation reported a relative standard deviation of <10% for each antibiotic. The recovery ranged between 97 and 103% for all compounds. This method could represent a useful tool for TDM of antibiotics.

Therapeutic Drug Monitoring Is a Feasible Tool to Personalize Drug Administration in Neonates Using New Techniques: An Overview on the Pharmacokinetics and Pharmacodynamics in Neonatal Age.

Therapeutic drug monitoring (TDM) should be adopted in all neonatal intensive care units (NICUs), where the most preterm and fragile babies are hospitalized and treated with many drugs, considering that organs and metabolic pathways undergo deep and progressive maturation processes after birth. Different developmental changes are involved in interindividual variability in response to drugs. A crucial point of TDM is the choice of the bioanalytical method and of the sample to use. TDM in neonates is primarily used for antibiotics, antifungals, and antiepileptic drugs in clinical practice. TDM appears to be particularly promising in specific populations: neonates who undergo therapeutic hypothermia or extracorporeal life support, preterm infants, infants who need a tailored dose of anticancer drugs. This review provides an overview of the latest advances in this field, showing options for a personalized therapy in newborns and infants.

Validation of Heel Stick Microsampling To Optimize Micafungin Doses in Neonates and Young Infants.

Major gaps exist in our knowledge of antimicrobial pharmacokinetics in critically ill neonates and infants that require validated microsampling and bioanalysis methods to support therapeutic drug monitoring. We compared serially collected intravenous (i.v.) and heel stick capillary (HSC)-sampled plasma concentrations of micafungin (8 mg/kg) in eight infants born preterm with systemic candidiasis. The mean (standard deviation) micafungin area under the plasma concentration-time curve to infinity (AUCinf) was 316 (65.0) h · mg/liter based on HSC concentrations that strongly correlated (R2 = 0.92) with i.v. values to support dose adjustment.

Eltrombopag-Induced Acute Liver Failure in a Pediatric Patient: A Pharmacokinetic and Pharmacogenetic Analysis.

Eltrombopag is an oral thrombopoietin receptor agonist approved for the treatment of patients with chronic idiopathic thrombocytopenic purpura (ITP), who are more than 1 year old, and show poor response to first-line therapy. ITP is a hematological disorder characterized by isolated thrombocytopenia in the absence of secondary causes or disorders. Eltrombopag is generally well tolerated in the pediatric population; therefore, therapeutic drug monitoring (TDM) is not usually performed in clinical practice.We presented the case study of a 3-year-old girl with chronic ITP. She arrived in the pediatric intensive care unit with acute liver failure due to eltrombopag toxicity despite taking the standard drug dosage. A very high eltrombopag plasma concentration, indicating drug toxicity, was found through TDM. The patient also carried the allelic variations that are involved in drug metabolism [CYP2C8 and UDP glucuronosyltransferase (UGT) 1A1 (UGT1A1)] and drug cellular transportation [ABCG2 (ATP-binding cassette G2)]. This observation highlights the importance of using TDM and pharmacogenetic approaches to manage patients' unusual complications associated with standard pharmacological treatment regimens.

High-Dose Micafungin for Preterm Neonates and Infants with Invasive and Central Nervous System Candidiasis.

High doses of micafungin are advocated in neonates with systemic candidiasis, but limited pharmacokinetic (PK) and safety data are available to support their use. Eighteen preterm neonates and infants with systemic candidiasis, three of whom had meningitis, were treated for at least 14 days with 8 to 15 mg/kg of body weight/day of intravenous micafungin. Plasma micafungin concentrations (four measurements for each patient) were determined after the third dose, and the cerebrospinal fluid (CSF) micafungin concentrations in three patients were also obtained. Population PK analyses were used to identify the optimal model, and the model was further validated using external data (n = 5). The safety of micafungin was assessed by measurement of the levels of liver and kidney function biomarkers. The mean age and weight at the initiation of treatment were 2.33 months (standard deviation [SD], 1.98 months) and 3.24 kg (SD, 1.61 kg), respectively. The optimal PK model was one that scaled plasma clearance to weight and the transaminase concentration ratio. The CSF of three patients was sampled, and the observed concentrations were between 0.80 and 1.80 mg/liter. The model-predicted mean micafungin area under the concentration-time curve over 24 h was 336 mg · h/liter (SD, 165 mg · h/liter) with the 10-mg/kg/day dosage. Eighteen of the 23 subjects (78.2%) had clinical resolution of their infection, but 5 had neurologic impairments. Among the transaminases, alkaline phosphatase measurements were significantly higher posttreatment, with a geometric mean ratio of 1.17 (90% confidence interval, 1.01, 1.37). Furthermore, marked elevations in the gamma-glutamyltransferase (GGT) level were observed in three patients treated with 10- to 15-mg/kg/day doses, and improvement of the GGT level was noted after a dose reduction. Higher weight-based doses of micafungin were generally well tolerated in neonates and infants and achieved pharmacokinetic profiles predictive of an effect.

Reverse-phase high-performance liquid chromatography for the simultaneous determination of sildenafil and N-desmethyl sildenafil in plasma of children.

Sildenafil is a selective inhibitor of cGMP-specific type 5 phosphodiesterase used for the treatment of pulmonary arterial hypertension (PAH) in the adults. In pediatrics, PAH treatment options include the off-label use of sildenafil. Sildenafil is metabolized in the liver by cytocrome P450 into its active metabolite, N-desmethyl sildenafil. The determination of plasma levels of sildenafil and N-desmethyl sildenafil could be useful for therapy optimization and pharmacokinetic studies. We have developed and validated a method for the quantification of sildenafil and its metabolite in plasma of children by rapid extraction, using high-performance liquid chromatography with ultraviolet detection. The calibration range was fitted at least square model (r2 ≥ 0.999), with an accuracy and an intra- and inter-day relative standard deviation <15% for both analytes. The mean recovery was 102.5% for sildenafil and 101.8% for N-desmethyl sildenafil. This simple method could be successfully used in children with PAH under treatment with sildenafil.

Simultaneous post-neurosurgical ventriculitis and bacteraemia by two different strains of KPC-producing K. pneumoniae successfully treated with meropenem/vaborbactam and high dose of fosfomycin.

OBJECTIVE: A case of post-neurosurgical ventriculitis caused by a KPC-producing Klebsiella pneumoniae (KPC-Kp) with a ceftazidime/avibactam-resistant, meropenem-susceptible phenotype is reported. METHODS AND RESULTS: The patient had a concomitant bloodstream infection with a wild-type KPC-Kp with a ceftazidime/avibactam-susceptible, meropenem-resistant phenotype. Prolonged treatment with intravenous fosfomycin and meropenem/vaborbactam achieved clinical success. Therapeutic drug monitoring performed during the first days of treatment showed for the first time that vaborbactam efficiently penetrates cerebrospinal fluid. In contrast, meropenem was undetectable in cerebrospinal fluid at each sampling, suggesting that additional doses of meropenem may be required to appropriately prescribe meropenem/vaborbactam for central nervous system infections. Plasma and cerebrospinal fluid levels of fosfomycin were adequate, confirming the potential of this agent possibly even in the fight against multidrug-resistant organisms. CONCLUSIONS: This case highlights the need for therapeutic drug monitoring as a crucial tool for optimizing treatment in complicated cases where the pharmacokinetic behaviour of antibiotics is difficult to predict.

A New and Rapid LC-MS/MS Method for the Determination of Cysteamine Plasma Levels in Cystinosis Patients.

Cystinosis is a rare lysosomal storage disorder caused by autosomal recessive mutations in the CTNS gene that encodes for the cystine transporter cystinosin, which is expressed on the lysosomal membrane mediating the efflux of cystine. Cysteamine bitartrate is a cystine-depleting aminothiol agent approved for the treatment of cystinosis in children and adults. In this study, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of cysteamine levels in plasma samples. This LC-MS/MS method was validated according to the European Medicines Agency (EMA)'s guidelines for bioanalytical method validation. An ultra-performance liquid chromatograph (UPLC) coupled with a 6470 mass spectrometry system was used for cysteamine determination. Our validated method was applied to plasma samples from n = 8 cystinosis patients (median, interquartile range (IQR) = 20.5, 8.5-26.0 years). The samples were collected before cysteamine oral administration (pre-dose) and 1 h after (post-dose). Our bioanalytical method fulfilled the regulatory guidelines for method validation. The cysteamine plasma levels in pre-dose samples were 2.57 and 1.50-3.31 µM (median and IQR, respectively), whereas the post-dose samples reported a cysteamine median concentration of 28.00 µM (IQR: 17.60-36.61). Our method allows the rapid determination of cysteamine plasma levels. This method was successfully used in cystinosis patients and, therefore, could be a useful tool for the evaluation of therapy adherence and for future pharmacokinetic (PK) studies involving a higher number of subjects.

Pharmacokinetic Evaluation of Oral Viscous Budesonide in Paediatric Patients with Eosinophilic Oesophagitis in Repaired Oesophageal Atresia.

Eosinophilic oesophagitis is a long-term complication of oesophageal atresia (EA), an uncommon condition that affects approximately 1 in 3500 infants. An exploratory, open-label phase 2 clinical trial was conducted in paediatric eosinophilic oesophagitis after oesophageal atresia (EoE-EA) to assess the safety, pharmacokinetics, and efficacy of oral viscous budesonide (OVB). In total, eight patients were enrolled in the study and assigned to a twice-daily dosing regimen of either 0.8 or 1 mg OVB, depending on age and height, administered for 12 weeks. OVB was safe and effective in the treatment of EoE-EA. The current investigation focuses on the pharmacokinetics of budesonide and the impact of an oral viscous formulation on its absorption and bioavailability. Using a non-linear mixed effects approach, two distinct absorption profiles were identified, despite marked interindividual variability in drug concentrations. Budesonide exposure was higher than previously reported in children following oral inhalation. Even though no significant effect has been observed on serum cortisol levels, future studies should consider exploring different doses, schedules, and/or treatment durations, as there may be an opportunity to reduce the risk of cortisol suppression.

Utilization of volumetric absorptive microsampling and dried plasma spot for quantification of anti-fungal triazole agents in pediatric patients by using liquid chromatography-tandem mass spectrometry.

BACKGROUND: Recently, increasing attention has been paid to the use of microsampling techniques for therapeutic drug monitoring (TDM) in neonatal and pediatric populations. Volumetric Absorptive Microsampling (VAMS) has been introduced in the market under the name Mitra® (Neoteryx). These devices consist of porous absorbent tips that allow collection of fixed blood volumes (10-30 µL) to overcome the DBS-related hematocrit effect. Here, the authors analyzed the concentrations of triazole agents (voriconazole, posaconazole, and isavuconazole) in VAMS and dried plasma spot (DPS) samples. METHODS: Fifty whole blood samples were obtained from pediatric patients subjected to systemic anti-fungal therapy. VAMS were collected by dipping the tip into whole blood before centrifugation for plasma recovery. Then, 30 µL of plasma was carefully spotted on filter paper to obtain DPS. Anti-fungal concentrations were measured using a validated LC-MS/MS kit (MassTox® Antimycotic Drugs/EXTENDED) provided by Chromsystems (Chromsystems Instruments & Chemicals). Drug concentrations in VAMS and DPS samples were compared to those in fresh plasma using Passing-Bablok and Bland-Altman tests. RESULTS: Plasma concentrations of voriconazole, posaconazole, and isavuconazole were positively and significantly correlated with those obtained in VAMS and DPS samples (Spearman r range, 0.82-0.94, p < 0.001). Data were further analyzed using the Bland-Altman test, which showed a % mean difference compared to fresh plasma of -15.06-10.98 (range). The stability of both VAMS and DPS was ensured for at least 14 d at room temperature. CONCLUSIONS: These results demonstrate that VAMS and DPS can be used for the TDM of anti-fungal agents. Owing to their stability, both sampling devices can be easily stored and shipped, without the need for refrigeration, to TDM laboratories that facilitate remote TDM applications. Finally, VAMS could be particularly suitable for pediatric and neonatal patients because they allow the collection of a few microliters of blood, thus improving ethical and compliance limitations.

Plasma and Cerebrospinal Fluid Concentrations of Micafungin Administered at High Doses in Critically Ill Infants with Systemic Candidiasis: A Pooled Analysis of Two Studies.

Background: Neonates may require higher doses of micafungin than adults to reach the therapeutic effect for increased plasma clearance. Only poor and inconclusive data are available still now to support this hypothesis, especially with regard to central nervous system micafungin concentrations. To assess the pharmacokinetics of increased doses (8 to 15 mg/kg/day) of micafungin in preterm and term neonates with invasive candidiasis and to complete previously presented results, we analyzed the pharmacokinetic data on a total of 53 newborns treated with micafungin, whereby 3 of them had Candida meningitis and hydrocephalus. Methods: Fifty-three neonates with systemic candidiasis, three of them with meningitis, were treated for at least 14 days with intravenous micafungin (Mycamine®) at a dosage ranging from 8 to 15 mg/kg/day. Plasma and cerebrospinal fluid (CSF) concentrations of micafungin were measured before the drug administration and at 1, 2, and 8 h after the end of the infusion using high-performance liquid chromatography (HPLC). Systemic exposure was assessed according to AUC0-24, plasma clearance (CL), and half-life measured in 52/53 patients, divided by chronological age. Results and conclusions: The mean micafungin clearance is higher in neonates than in older infants (0.036 L/h/kg before 28 days of life versus 0.028 L/h/kg after 120 days). The drug half-life is shorter in neonates than in older patients (13.5 h before 28 days of life versus 14.4 h after 120 days). With doses ranging between 8 and 15 mg/kg/day, micafungin crosses the blood-brain barrier reaching therapeutic levels in CSF.