A simple extemporaneous oral suspension of aprepitant yields sufficient pharmacokinetic exposure in children.

INTRODUCTION: Aprepitant is used for the treatment of chemotherapy induced nausea and vomiting. A liquid formulation is needed for treatment of young children. However, the commercial (powder for) suspension was not available worldwide for a prolonged period of time and, therefore, a 10 mg/mL aprepitant oral suspension was extemporarily prepared to prevent suboptimal antiemetic treatment. The current pharmacokinetic study was developed to investigate whether this extemporaneous oral suspension offers an appropriate treatment option. METHODS: From 49 pediatric patients (0.7-17.9 years) 235 plasma concentrations were collected. Patients were either treated with our extemporaneous oral suspension (n = 26; 53%), commercially available capsules (n = 18; 37%), or the intravenous prodrug formulation of aprepitant (fosaprepitant, n = 5; 10%). Pharmacokinetic analyses were performed using nonlinear mixed effects modelling. RESULTS: A one-compartment model adequately described the pharmacokinetics of aprepitant in children. The bioavailability of the extemporaneous oral suspension was not significantly different to that of the capsules (P = 0.26). The observed bioavailability throughout the total population was 83% (95% CI 69%-97%). The absorption of the extemporaneous oral suspension was 39.4% (95%CI 19.5-57.4%) faster than that of capsules (mean absorption time of 1.78 h (95%CI 1.32-2.35), but was comparable to that of the commercial oral suspension. The median area under the curve after (fos)aprepitant was 22.2 mg/L*h (range 8.9-50.3 mg/L*h) on day 1. CONCLUSION: Our extemporaneous oral suspension is an adequate alternative for the commercially (un)available oral suspension in young children. An adequate exposure to aprepitant in children was yielded and the bioavailability of the extemporaneous suspension was comparable to capsules.

Overestimation of the effect of (fos)aprepitant on intravenous dexamethasone pharmacokinetics requires adaptation of the guidelines for children with chemotherapy-induced nausea and vomiting.

PURPOSE: Chemotherapy-induced nausea and vomiting (CINV) are common side effects in pediatric oncology treatment. Besides 5-HT3-antagonists, both dexamethasone and aprepitant are cornerstone drugs in controlling these side effects. Based on results of adult studies, the dexamethasone dose is reduced by 50% when combined with aprepitant, because of a drug-drug interaction, even though data on the interaction in children is lacking. The current study was developed to investigate the effect of aprepitant on dexamethasone clearance (CL) in children, in order to assess if dexamethasone dose reduction for concomitant use of aprepitant is appropriate in the current antiemetic regimen. METHODS: In total, 65 children (0.6-17.9 years), receiving intravenous or oral antiemetic therapy (dexamethasone ± aprepitant) as standard of care, were included. 305 dexamethasone plasma concentrations were determined using LC-MS/MS. An integrated dexamethasone and aprepitant pharmacokinetic model was developed using non-linear mixed effects modelling in order to investigate the effect of aprepitant administration on dexamethasone CL. RESULTS: In this population, dexamethasone CL in patients with concomitant administration of aprepitant was reduced by approximately 30% of the uninhibited CL (23.3 L/h (95% confidence interval 20.4-26.0)). This result is not consistent with the results of adult studies (50% reduction). This difference was not age dependent, but might be related to the route of administration of dexamethasone. Future studies are needed to assess the difference in oral/intravenous dexamethasone. CONCLUSION: When dexamethasone is given intravenously as a component of triple therapy to prevent CINV in children, we advise to reduce the dexamethasone dose by 30% instead of 50%.

A Population Pharmacokinetic Modelling Approach to Unravel the Complex Pharmacokinetics of Vincristine in Children.

BACKGROUND: Vincristine, a chemotherapeutic agent that extensively binds to ß-tubulin, is commonly dosed at 1.4-2.0 mg/m2 capped at 2 mg. For infants, doses vary from 0.025-0.05 mg/kg or 50-80% of the mg/m2 dose. However, evidence for lower doses in infants compared to older children is lacking. This study was conducted to unravel the complex pharmacokinetics of vincristine, including the effects of age, to assist optimal dosing in this population. METHODS: 206 patients (0.04-33.9 years; 25 patients < 1 years), receiving vincristine, with 1297 plasma concentrations were included. Semi-mechanistic population pharmacokinetic analyses were performed using non-linear mixed effects modelling. RESULTS: A three-compartment model, with one saturable compartment resembling saturable binding to ß-tubulin and thus, saturable distribution, best described vincristine pharmacokinetics. Body weight and age were covariates significantly influencing the maximal binding capacity to ß-tubulin, which increased with increasing body weight and decreased with increasing age. Vincristine clearance (CL) was estimated as 30.6 L/h (95% confidence interval (CI) 27.6-33.0), intercompartmental CL (Q) as 63.2 L/h (95%CI 57.2-70.1), volume of distribution of the central compartment as 5.39 L (95%CI 4.23-6.46) and of the peripheral compartment as 400 L (95%CI 357-463) (all parameters correspond to a patient of 70 kg). The maximal binding capacity was 0.525 mg (95%CI 0.479-0.602) (for an 18 year old patient of 70 kg), with a high association rate constant, fixed at 1300 /h and a dissociation constant of 11.5 /h. INTERPRETATION: A decrease of vincristine ß-tubulin binding capacity with increasing age suggests that young children tolerate higher doses of vincristine.

Short-Term Daily Intake of Polydextrose Fiber Does Not Shorten Intestinal Transit Time in Constipated Adults: A Randomized Controlled Trial.

Chronic constipation (CC) remains a common gastrointestinal (GI) disorder that conveys a substantial healthcare burden. Expert guidelines recommend increasing fiber intake, yet the clinical evidence to support this needs strengthening for specific fibers. The aim was to evaluate changes in intestinal transit time and GI symptoms in CC patients who consumed polydextrose. In a randomized, double-blind, placebo-controlled trial, 128 adults with CC received 8 g or 12 g polydextrose, or placebo, daily for 4 weeks. Transit time, as primary outcome, was assessed by radiopaque marker distribution after 2-weeks intervention. Bowel habits, GI symptoms and quality of life (QOL) were assessed by questionnaire, including the Patient-Assessment of Constipation (PAC) Symptoms (SYM), and PAC-QOL. Following 2-weeks intervention, no reduction was seen in transit time in any group and following 2- or 4-weeks intervention, no improvements were seen in stool frequency or consistency in any group. After 2-weeks intervention with 8 g/day polydextrose an improvement was seen in the PAC-SYM rectal score (p = 0.041). After 4-weeks intervention both rectal (p = 0.049) and stool (p = 0.029) scores improved while improvement in the QOL satisfaction score did not reach significance (p = 0.071). Overall, the results suggest that 2-weeks consumption of 8 or 12 g/day polydextrose does not significantly improve physiological measures of gut function in CC adults. Longer term consumption may improve clinical measures, but further studies will be required to substantiate this.

A cost of illness study of hypoglycaemic events in insulin-treated diabetes in the Netherlands.

OBJECTIVES: Patients with diabetes mellitus are at a risk for hypoglycaemia. Besides the burden of hypoglycaemia for patients, hypoglycaemia poses an economic burden to society. The aim of this study was to calculate the per patient societal costs of hypoglycaemia among patients with type1 diabetes (T1DM) and type 2 diabetes (T2DM) on insulin therapy in the Netherlands. METHODS: To calculate the costs of hypoglycaemia, data from the Global Hypoglycaemia Assessment Tool (HAT) study were used. Dutch patients were selected from the HAT study database and data regarding healthcare resource use, informal care use and productivity losses were combined with Dutch unit costs to calculate the per patient 4-week costs of patients experiencing hypoglycaemia. Besides these 4-week costs, costs per hypoglycaemic event were calculated by dividing the study population total 4-week costs by the total number of events in this period. RESULTS: Mean 4-week total costs of hypoglycaemia amounted to €163 (SD, €870) in T1DM and €134 (SD, €364) in T2DM. While productivity costs were the most important cost driver of hypoglycaemia in patients with T1DM (accounting for 72% of the total costs), costs of hypoglycaemia in patients with T2DM were almost entirely driven by costs within the healthcare sector (accounting for 98% of the total costs). Mean costs of a severe hypoglycaemic event were €828 and €508 in T1DM and T2DM, respectively, whereas mean costs of a non-severe event were almost zero. CONCLUSIONS: This study showed that the economic burden of severe hypoglycaemia is substantial. The prevention of hypoglycaemia could therefore not only reduce the burden for patients, but also the economic burden to society.

Impact of hypoglycaemia on patient-reported outcomes from a global, 24-country study of 27,585 people with type 1 and insulin-treated type 2 diabetes.

AIMS: Data on the impact of hypoglycaemia on patients' daily lives and diabetes self-management, particularly in developing countries, are lacking. The aim of this study was to assess fear of, and responses to, hypoglycaemia experienced by patients globally. MATERIALS AND METHODS: This non-interventional, multicentre, 4-week prospective study using self-assessment questionnaires and patient diaries consisted of 27,585 patients, ≥18years, with type 1 diabetes (n=8022) or type 2 diabetes (n=19,563) treated with insulin for >12months, at 2004 sites in 24 countries worldwide. RESULTS: Increased blood glucose monitoring (69.7%) and seeking medical assistance (62.0%) were the most common responses in the 4weeks following hypoglycaemic events for patients with type 1 diabetes and type 2 diabetes, respectively. Approximately 44% of patients with type 1 diabetes or type 2 diabetes increased calorie intake in response to a hypoglycaemic episode. Following hypoglycaemia, 3.9% (type 1 diabetes) and 6.2% (type 2 diabetes) of patients took leave from work or study. Regional differences in fear of, and responses to, hypoglycaemia were evident - in particular, a lower level of hypoglycaemic fear and utilisation of healthcare resources in Northern Europe and Canada. CONCLUSIONS: Hypoglycaemia has a major impact on patients and their behaviour. These global data for the first time reveal regional variations in response to hypoglycaemia and highlight the importance of patient education and management strategies.

Series: Pragmatic trials and real world evidence: Paper 2. Setting, sites, and investigator selection.

This second article in the series on pragmatic trials describes the challenges in selection of sites for pragmatic clinical trials and the impact on validity, precision, and generalizability of the results. The selection of sites is an important factor for the successful execution of a pragmatic trial and impacts the extent to which the results are applicable to future patients in clinical practice. The first step is to define usual care and understand the heterogeneity of sites, patient demographics, disease prevalence and country choice. Next, specific site characteristics are important to consider such as interest in the objectives of the trial, the level of research experience, availability of resources, and the expected number of eligible patients. It can be advisable to support the sites with implementing the trial-related activities and minimize the additional burden that the research imposes on routine clinical practice. Health care providers should be involved in an early phase of protocol development to generate engagement and ensure an appropriate selection of sites with patients who are representative of the future drug users.