A Comparison of Pediatric and Adult Safety Studies for Antipsychotic and Antidepressant Drugs Submitted to the United States Food and Drug Administration

Population pharmacokinetics of olanzapine in pediatric patients with psychiatric disorders

OBJECTIVE

To develop and validate a population pharmacokinetic (PPK) model of oral olanzapine in pediatric Chinese patients in order to individualize therapy in this population.

METHODS

A total of 897 serum concentrations from 269 pediatric patients taking oral olanzapine (ages 8-17 years) were collected. Demographic parameters, biological characteristics and concomitant medications were investigated as covariates. The data were analyzed using a nonlinear mixed-effects modeling approach. Bootstrapping (1000 runs), normalized prediction distribution error (NPDE), and external validation of 62 patients were employed. Simulations were performed to explore the individualized dosing regimens in various situations.

RESULTS

The one-compartment model with first-order absorption and elimination had an apparent clearance (CL/F) of 10.38 L/h, a distribution volume (V/F) of 9.41 L/kg and an absorption rate constant (Ka) fixed at 0.3 h-1. The equation was CL∕F (L∕h) = 10.38 × (body weight∕60)0.25 ×1.33 (if male) × 0.71 (if co-occurrence of infection) × 0.51 (if co-therapy with fluvoxamine) × 1.27 (if co-therapy with sertraline) × 1.43 (if co-therapy with valproate). The final model had satisfactory stability, robustness, and predictive ability. The results from a simulation suggested the oral olanzapine doses required for male and female pediatric patients weighing between 40 and 60 kg without co-medication were 10-15 mg/day and 7.5-10 mg/day, respectively, and dosage adjustments should be based on sex and body weight; and co-administrated with valproate, sertraline, or fluvoxamine.

CONCLUSION

This model may help individualize optimum dosing of oral olanzapine for pediatric patients.

Personalized Dosing of Medicines for Children: A Primer on Pediatric Pharmacometrics for Clinicians

The widespread use of drugs for unapproved purposes remains common in children, primarily attributable to practical, ethical, and financial constraints associated with pediatric drug research. Pharmacometrics, the scientific discipline that involves the application of mathematical models to understand and quantify drug effects, holds promise in advancing pediatric pharmacotherapy by expediting drug development, extending applications, and personalizing dosing. In this review, we delineate the principles of pharmacometrics, and explore its clinical applications and prospects. The fundamental aspect of any pharmacometric analysis lies in the selection of appropriate methods for quantifying pharmacokinetics and pharmacodynamics. Population pharmacokinetic modeling is a data-driven method ('top-down' approach) to approximate population-level pharmacokinetic parameters, while identifying factors contributing to inter-individual variability. Model-informed precision dosing is increasingly used to leverage population pharmacokinetic models and patient data, to formulate individualized dosing recommendations. Physiologically based pharmacokinetic models integrate physicochemical drug properties with biological parameters ('bottom-up approach'), and is particularly valuable in situations with limited clinical data, such as early drug development, assessing drug-drug interactions, or adapting dosing for patients with specific comorbidities. The effective implementation of these complex models hinges on strong collaboration between clinicians and pharmacometricians, given the pivotal role of data availability. Promising advancements aimed at improving data availability encompass innovative techniques such as opportunistic sampling, minimally invasive sampling approaches, microdialysis, and in vitro investigations. Additionally, ongoing research efforts to enhance measurement instruments for evaluating pharmacodynamics responses, including biomarkers and clinical scoring systems, are expected to significantly bolster our capacity to understand drug effects in children.

Identification and treatment of individuals with childhood-onset and early-onset schizophrenia

Approximately 8 % of patients with schizophrenia are diagnosed before age 18, and 18 % experience their first symptoms before age 18. This narrative review explores the management of patients with early-onset schizophrenia (EOS) and childhood-onset schizophrenia (COS) from diagnosis to their transition to adult care settings. Early diagnosis of schizophrenia in children and adolescents is essential for improving outcomes, but delays are common due to overlapping of symptoms with developmental phenomena and other psychiatric conditions, including substance use, and lack of clinicians' awareness. Once diagnosed, antipsychotic treatment is key, with specific second-generation agents generally being preferred due to better tolerability and their broader efficacy evidence-base in youth. Dosing should be carefully individualized, considering age-related differences in drug metabolism and side effect liability. Clinicians must be vigilant in detecting early non-response and consider switching or dose escalation when appropriate. Since early age of illness onset is a consistent risk factor for treatment-resistant schizophrenia (TRS), clinicians need to be competent in diagnosing TRS and using clozapine. Since COS and EOS are associated with cognitive deficits and impaired functioning, psychosocial interventions should be considered to improve overall functioning and quality of life. Good long-term outcomes depend on continuous treatment engagement, and successful transitioning from pediatric to adult care requires careful planning, early preparation, and collaboration between pediatric and adult clinicians. Targeting functional outcomes and quality of life in addition to symptom remission can improve overall patient well-being. Comprehensive evaluations, age-specific assessments, and targeted interventions are needed to address the unique challenges of EOS and COS.

Clinical Utility and Implementation of Pharmacogenomics for the Personalisation of Antipsychotic Treatments

Decades of pharmacogenetic research have revealed genetic biomarkers of clinical response to antipsychotics. Genetic variants in antipsychotic targets, dopamine and serotonin receptors in particular, and in metabolic enzymes have been associated with the efficacy and toxicity of antipsychotic treatments. However, genetic prediction of antipsychotic response based on these biomarkers is far from accurate. Despite the clinical validity of these findings, the clinical utility remains unclear. Nevertheless, genetic information on CYP metabolic enzymes responsible for the biotransformation of most commercially available antipsychotics has proven to be effective for the personalisation of clinical dosing, resulting in a reduction of induced side effects and in an increase in efficacy. However, pharmacogenetic information is rarely used in psychiatric settings as a prescription aid. Lack of studies on cost-effectiveness, absence of clinical guidelines based on pharmacogenetic biomarkers for several commonly used antipsychotics, the cost of genetic testing and the delay in results delivery hamper the implementation of pharmacogenetic interventions in clinical settings. This narrative review will comment on the existing pharmacogenetic information, the clinical utility of pharmacogenetic findings, and their current and future implementations.

(-)-Epigallocatechin gallate alleviates chronic unpredictable mild stress-induced depressive symptoms in mice by regulating the mTOR autophagy pathway and inhibiting NLRP3 inflammasome activation

Depression is a global public health issue that is widely studied due to the large number of people it affects and its serious consequences. Clinical studies have shown that regular tea consumption may reduce depression risk. (-)-Epigallocatechin gallate (EGCG), the main tea polyphenol, was observed to alleviate depression, but the underlying mechanism has not been elucidated. In this study, chronic unpredictable mild stress (CUMS) was used to induce depression-like behavior in mice, and behavioral tests, such as sucrose preference test and forced swim test, were performed. Then, ELISA, western blot and QT-PCR tests were used to assess the expression of the key components of the NLRP3 inflammasome and its downstream inflammatory effectors (e.g., IL-1β, IL-18), autophagy markers (Beclin-1, LC3, P62) and apoptosis markers (Bax, Bcl-2) in mouse brain tissues. Changes in serum lipid levels were also assessed. EGCG alleviated CUMS-induced depression-like behavioral changes in mice, reduced activation of the NLRP3 inflammasome, inhibited the mTOR signaling pathway, restored autophagy levels, reduced apoptosis marker expression and attenuated abnormal changes in blood lipid levels. Our study demonstrates that EGCG exerts antidepressive effects through multiple mechanisms, providing new insight into the pathological mechanism of depression and laying the foundation for the development of new therapeutic measures.

Olanzapine Pharmacokinetics: A Clinical Review of Current Insights and Remaining Questions

Olanzapine is one of the most widely used antipsychotics since its initial approval by the US Food and Drug Administration in 1996 and has undergone extensive pharmacokinetic study. Despite being utilized in clinical psychiatry for decades, there remain questions regarding the variety of available formulations, the utility of therapeutic drug monitoring, altered kinetic properties in special populations/medical illnesses, the use of high-dose olanzapine, and drug interactions, among many others. We performed a narrative literature review of olanzapine pharmacokinetics in June 2023 using the US National Library of Medicine's PubMed.gov resource (https://www.ncbi.nlm.nih.gov/pubmed) and Google Scholar. Herein, we review clinically relevant aspects of olanzapine pharmacokinetic data while highlighting knowledge gaps and potential areas of future study.

Evaluation of off-label medication use and drug safety in a pediatric intensive care unit

Safety and efficacy are essential in the process of disease treatment. However, off-label medication use is inevitable because various medications do not contain regulatory labels for pediatric use. We aimed to examine off-label medication use and analyze the risk factors correlated with adverse drug reactions (ADRs). This study was performed retrospectively using electronic medical data from a pediatric intensive care unit (PICU) of a tertiary hospital in Korea from July 2019 to June 2020. A total 6,183 prescribed medications from 502 PICU patients were examined in the present study. A total of 80% were infants or children, and 96.0% of them were treated with off-label medications. It was discovered that 4,778 off-label cases (77.2%) of the top 100 drugs had prescriptions with dosage (67.8%). Drugs prescribed to patients admitted to the cardiothoracic department (odds ratio [OR], 3.248; p = 0.019), total number of medications (OR, 1.116; p = 0.001), and length of PICU stay of ≥ 7 days (OR, 4.981; p = 0.008) were significantly associated with ADRs. ADRs were noted to be more severe in off-label use (p = 0.0426). For appropriate medication use, evidence regarding the safety of off-label medications is required and ultimately reflected in the official regulation.

Current knowledge, challenges and innovations in developmental pharmacology: A combined conect4children Expert Group and European Society for Developmental, Perinatal and Paediatric Pharmacology White Paper

Developmental pharmacology describes the impact of maturation on drug disposition (pharmacokinetics, PK) and drug effects (pharmacodynamics, PD) throughout the paediatric age range. This paper, written by a multidisciplinary group of experts, summarizes current knowledge, and provides suggestions to pharmaceutical companies, regulatory agencies and academicians on how to incorporate the latest knowledge regarding developmental pharmacology and innovative techniques into neonatal and paediatric drug development. Biological aspects of drug absorption, distribution, metabolism and excretion throughout development are summarized. Although this area made enormous progress during the last two decades, remaining knowledge gaps were identified. Minimal risk and burden designs allow for optimally informative but minimally invasive PK sampling, while concomitant profiling of drug metabolites may provide additional insight in the unique PK behaviour in children. Furthermore, developmental PD needs to be considered during drug development, which is illustrated by disease- and/or target organ-specific examples. Identifying and testing PD targets and effects in special populations, and application of age- and/or population-specific assessment tools are discussed. Drug development plans also need to incorporate innovative techniques such as preclinical models to study therapeutic strategies, and shift from sequential enrolment of subgroups, to more rational designs. To stimulate appropriate research plans, illustrations of specific PK/PD-related as well as drug safety-related challenges during drug development are provided. The suggestions made in this joint paper of the Innovative Medicines Initiative conect4children Expert group on Developmental Pharmacology and the European Society for Developmental, Perinatal and Paediatric Pharmacology, should facilitate all those involved in drug development.

Pharmacokinetics, Safety, and Tolerability of Cariprazine in Pediatric Patients with Bipolar I Disorder or Schizophrenia

Objective: Cariprazine is a dopamine D₃-preferring D₃/D₂ and serotonin 5-HT_1A receptor partial agonist approved to treat adults with schizophrenia and manic/mixed or depressive episodes associated with bipolar I disorder. This sequential-cohort, dose-escalation study was the first to evaluate the pharmacokinetic, safety, and tolerability profile of cariprazine and its two major active metabolites, desmethyl-cariprazine (DCAR) and didesmethyl-cariprazine (DDCAR), in pediatric patients with schizophrenia or bipolar I disorder. Methods: This phase I open-label study enrolled patients with schizophrenia (13-17 years of age) or bipolar I disorder (10-17 years of age). Patients met the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for schizophrenia or bipolar I disorder and had Positive and Negative Syndrome Scale (PANSS) total scores ≥70 or Young Mania Rating Scale (YMRS) total scores ≥20. Patients were assigned to one of four treatment groups to receive 6 weeks of cariprazine treatment through slow titration to 1.5, 3, or 4.5 mg/d or fast titration to 4.5 mg/d. Pharmacokinetics, adverse events (AEs), and various safety parameters were analyzed. Efficacy was evaluated as an exploratory outcome. Results: A total of 50 participants were enrolled. Based on mean trough levels, steady state appeared to be reached within 1-2 weeks for cariprazine and DCAR and within 4-5 weeks for DDCAR. Systemic exposure of cariprazine, DCAR, and DDCAR generally increased approximately in proportion to the increases in dose from 1.5 to 4.5 mg/d. The most frequent treatment-related, treatment-emergent AEs included sedation, parkinsonism, tremor, dystonia, and blurred vision. Improvements from baseline on the PANSS and YMRS were observed throughout treatment. Conclusion: In this first investigation of cariprazine in a pediatric population with schizophrenia or bipolar disorder, pharmacokinetic parameters were consistent with those observed in adults. Cariprazine appeared to be safe and tolerable in children and adolescents.

Low Rates of Clinician Monitoring for Second Generation Antipsychotic Medications in Community Pediatric Practice

Second generation antipsychotic (SGA) medications are frequently prescribed to pediatric patients in the United States. This retrospective observational study sought to ascertain the extent of adherence to established pediatric SGA monitoring guidelines in community practice. The team used the electronic health record to determine clinician adherence to SGA monitoring guidelines at baseline, 12-week, and annual times relative to prescribing an SGA. At the time of their SGA prescription, 5.5% of pediatric patients had received all of the orders according to the monitoring guidelines. Annually, 2.5% of patients had received the necessary orders to completely adhere to monitoring guidelines; 42% of patients received no monitoring orders. Monitoring was more likely for children who had multiple types of providers and interacted with the healthcare system beyond a traditional office visit. This research informs healthcare providers about the gap between prescribing and monitoring for SGA medications in community practice for pediatric populations.

Therapeutic drug monitoring in children and adolescents with schizophrenia and other psychotic disorders using risperidone

Risperidone is commonly used to treat different psychiatric disorders worldwide. Knowledge on dose–concentration relationships of risperidone treatment in children and adolescents with schizophrenia or other psychotic disorders is, however, scarce and no age-specific therapeutic ranges have been established yet. Multicenter data of a therapeutic drug monitoring service were analyzed to evaluate the relationship between risperidone dose and serum concentration of the active moiety (risperidone (RIS) plus its main metabolite 9-hydroxyrisperidone (9-OH-RIS)) in children and adolescents with psychotic disorders. Patient characteristics, doses, serum concentrations and therapeutic outcomes were assessed by standardized measures. The study also aimed to evaluate whether the therapeutic reference range for adults (20–60 ng/ml) is applicable for minors. In the 64 patients (aged 11–18 years) included, a positive correlation between daily dose and the active moiety (RIS_am) concentration was found (r_s = 0.49, p = 0.001) with variation in dose explaining 24% (r_s² = 0.240) of the variability in serum concentrations. While the RIS_am concentration showed no difference, RIS as well 9-OH-RIS concentrations and the parent to metabolite ratio varied significantly in patients with co-medication of a CYP2D6 inhibitor. Patients with extrapyramidal symptoms (EPS) had on average higher RISam concentrations than patients without (p = 0.05). Considering EPS, the upper threshold of the therapeutic range of RIS_am was determined to be 33 ng/ml. A rough estimation method also indicated a possibly decreased lower limit of the preliminary therapeutic range in minors compared to adults. These preliminary data may contribute to the definition of a therapeutic window in children and adolescents with schizophrenic disorders treated with risperidone. TDM is recommended in this vulnerable population to prevent concentration-related adverse drug reactions.

Monitoring of Adverse Drug Reaction-Related Parameters in Children, Youth, and Young Adults Prescribed Antipsychotic Drugs by General Practitioners

Objective: The aim of the study was to assess monitoring of adverse drug reaction (ADR)-related parameters in children, youth, and young adults treated with second-generation antipsychotic drugs (SGAs) prescribed by general practitioners (GPs). Methods: This retrospective follow-up study included children, youth, and young adults aged 0 - 24 years, who had an initial prescription of an SGA recorded in the Clinical Practice Research Datalink between 2000 and 2017, and who were prescribed an SGA more than once for a duration of at least 6 months. It included an assessment of which ADR-related physical parameters (weight, height, body-mass index, waist circumference, pulse, blood pressure, and heart examination) and laboratory parameters (glucose, HbA1c, lipids, and prolactin) were monitored in children, youth, and young adults at least once every 6-month period, stratified by sex, age categories, and calendar years. Results: In total, 7006 patients were included and the mean duration of follow-up was 1.6 years. Monitoring frequencies of all parameters were below 25%. Blood pressure and weight were monitored in 23.6% and 23.4%, respectively, of all children, youth, and young adults during the first half year; waist circumference was monitored in 0.2%. Females were monitored more often than males, some differences between age categories were observed, and monitoring frequencies increased after 2000, but did not exceed 35% in any year. Conclusion: Monitoring frequencies of ADR-related parameters in children, youth, and young adults treated with SGAs prescribed by a GP were low. Monitoring in primary care should be improved to enable a better evaluation of the benefit-risk balance during antipsychotic drug therapy.

Status of Medications Prescribed for Psychiatric Disorders in Korean Pediatric and Adolescent Patients

While mental health services for children are increasing, few psychiatric drugs have been approved for such use. We analyzed claim data from 19,557 South Korean pediatric and adolescent patients (<20 years) who were diagnosed with schizophrenia, bipolar disorder, major depressive disorder, anxiety disorder, attention deficit-hyperactivity disorder (ADHD), or a tic disorder. Among these diseases, depressive episodes were the most common, followed by an anxiety disorder, ADHD, bipolar disorder, tic disorder, and schizophrenia. For each disease, prescriptions were categorized as full-label (approved indication with pediatric dosing in the package insert (PI)), partial-label (approved indication without pediatric dosing in the PI), and contraindication (contraindicated for the specific pediatric age in the PI). For schizophrenia, major depressive disorder, and anxiety disorder, more than 50% of the patients were prescribed partial-labeled medications. Additionally, more than 5% of patients with major depressive disorder were prescribed medications that were contraindicated for their age group. Our findings reveal that children with full-labeled psychiatric conditions are commonly administered drugs that are not explicitly approved for either their disease state or age, including off-label and unlicensed drugs. To use pharmaceuticals more safely, expanding drug indications using real-world data are needed.

Collaboration Between Child and Adolescent Psychiatrists and Mental Health Pharmacists to Improve Treatment Outcomes

Access to mental health care is a long-standing challenge. The high, rising prevalence of mental health disorders and a shortage of mental health professionals has further strained an already fragile system. The clinical pharmacy is underutilized within the mental health space. Interdisciplinary collaboration between child psychiatrists and mental health pharmacists gives the psychiatrist more time for patient evaluation and treatment, while the psychiatric pharmacist provides drug monitoring, medication coordination, and education for providers. This collaborative approach improves outcomes, prevents adverse drug events, reduces hospital stays, lessens emergency department visits, and improves engagement and adherence.

Extrapolation of Efficacy and Dose Selection in Pediatrics: A Case Example of Atypical Antipsychotics in Adolescents With Schizophrenia and Bipolar I Disorder

Pediatric labeling information for novel atypical antipsychotics can be significantly delayed as the result of time lag between initial drug approval in adults and the completion of pediatric clinical trials. This delay can lead health care providers to rely on limited evidence-based literature to make critical therapeutic decisions for pediatric patients. Effective and scientifically justified dosing recommendations are needed to improve treatment outcomes in pediatric patients with schizophrenia and bipolar I disorder. Extrapolation-based drug development strategies rely on leveraging prior data to reduce evidentiary requirements for newer data in establishing drug efficacy. On January 13, 2020, the US Food and Drug Administration (FDA) released a general advice letter to sponsors highlighting the acceptance of extrapolating efficacy of atypical antipsychotics to pediatric patients. This review provides insight into the FDA's justification for extrapolating efficacy from adult to pediatric patients and provides a rationale for dose selection in pediatric patients with schizophrenia and bipolar I disorder.

Most Second-Generation Antipsychotic Prescriptions in Community Practice Are Neither FDA-Approved nor Within Prescribing Guideline Recommendations

OBJECTIVE

Second-generation antipsychotic (SGA) prescription use has become increasingly prevalent in the pediatric population, despite metabolic adverse effects. A significant number of SGA medications are prescribed for indications that are not approved by the FDA. This study aimed to quantify clinician adherence to the FDA and professional society indication, age, and dosing guidelines when prescribing SGA medications for pediatric patients.

METHODS

We used electronic health record data from 3 health care systems. We analyzed outpatient encounters where a pediatric patient was prescribed an SGA during an 18-month time frame. Clinician prescribing patterns were compared to a therapeutic regimen table created using professional society guidelines and FDA medication labels.

RESULTS

Most of the encounters listed an indication that was not documented as a recommended use (84.3%). Most prescriptions aligned with the generalized dose guidelines (93.8%) and age guidelines (94.9%). Clinicians were more likely to follow indication guidelines when prescribing risperidone, the highest adherence medication, compared with quetiapine, the lowest adherence medication (odds ratio [OR], 2.5; 95% CI, 1.1-6.0). Compared with prescriptions for younger children, clinicians were more likely to follow indication guidelines for children aged 13 to 15 years (OR, 2.8; 95% CI, 1.1-7.2) and 16 to 18 years (OR, 3.1; 95% CI, 1.2-8.1).

CONCLUSION

Community clinicians overall demonstrated a low level of adherence to indication guidelines when prescribing SGA medications to pediatric populations, while maintaining higher adherence to age and dosing guidelines. Older children were more likely to receive an SGA prescription for recommended indications compared with younger children.

Monitoring of Adverse Drug Reaction-Related Parameters in Children and Adolescents Treated With Antipsychotic Drugs in Psychiatric Outpatient Clinics

Aim: To assess the frequency of monitoring of adverse drug reaction (ADR) related parameters in children and adolescents treated with antipsychotic drugs in psychiatric outpatient clinics and the considerations when monitoring was not performed. Methods: This retrospective follow-up study included 100 randomly selected outpatients aged ≤18 years who had a first prescription of an antipsychotic drug recorded in the electronic medical records of psychiatric outpatient clinics between 2014 and 2017. They were followed for up to 3 years. This study assessed the frequency of monitoring for physical parameters (weight, height, body mass index, waist circumference, pulse, blood pressure, and an electrocardiogram) and laboratory parameters (glucose, lipids, and prolactin) before the first prescription of an antipsychotic drug as well as during its use. Monitoring frequencies were stratified by the patient characteristics (sex, age, cardiovascular risk factors, and use of other psychotropic drugs), and by location of antipsychotic drug initiation (psychiatric outpatient clinic or elsewhere). Additionally, this study assessed the considerations mentioned in the medical records for not monitoring ADR-related parameters. Results: Overall, physical parameters were monitored more frequently (weight: 85.9% during the first half-year) than laboratory parameters (glucose and cholesterol: both 23.5%). There were no significant differences in monitoring at least one physical as well as in monitoring at least one laboratory parameter during the baseline period and during the total follow-up of antipsychotic drug treatment between the patient characteristics. In total, 3% of the children and adolescents were never monitored for any physical parameter, and 54% were never monitored for any laboratory parameter. For a minority of the children (14.8%) who were never monitored for laboratory parameters, considerations were recorded in their medical records, including refusal by the child or parents and monitoring performed by the general practitioner or elsewhere. Conclusion: Monitoring frequencies of ADR-related parameters in children and adolescents treated with antipsychotic drugs in psychiatric outpatient clinics varied and especially monitoring of laboratory parameters was infrequent. Considerations why monitoring was not performed were rarely recorded. The optimal method of monitoring and documentation thereof should become clear to optimize the benefit-risk balance of antipsychotic drug treatment for each child.

Population pharmacokinetics of olanzapine in children

AIMS

The aim of this study was to evaluate the population pharmacokinetics (PopPK) of olanzapine in children and devise a model-informed paediatric dosing scheme.

METHODS

The PopPK of olanzapine was characterized using opportunistically collected plasma samples from children receiving olanzapine per standard of care for any indication. A nonlinear mixed effect modelling approach was employed for model development using the software NONMEM (v7.4). Simulations from the developed PopPK model were used to devise a paediatric dosing scheme that targeted comparable plasma exposures to adolescents and adults.

RESULTS

Forty-five participants contributed 83 plasma samples towards the analysis. The median (range) postnatal age and body weight of participants were 3.8 years (0.2-19.2) and 14.1 kg (4.2-111.7), respectively. The analysis was restricted to pharmacokinetic (PK) samples collected following enteral administration (oral and feeding tube). A one-compartment model with linear elimination provided an appropriate fit to the data. The final model included the covariates body weight and postmenstrual age (PMA) on apparent olanzapine clearance (CL/F). Typical CL/F and apparent volume of distribution (scaled to 70 kg) were 16.8 L/h (21% RSE) and 663 L (13% RSE), respectively. Developed dosing schemes used weight-normalized doses for children ≤6 months postnatal age or <15 kg and fixed doses for children ≥15 kg.

CONCLUSION

We developed a paediatric PopPK model for enterally-administered olanzapine. To our knowledge, this analysis is the first study to characterize the PK of olanzapine in participants ranging from infants to adolescents. Body weight and PMA were identified as influential covariates for characterizing developmental changes in olanzapine apparent clearance.

Perceived Versus Demonstrated Understanding of the Complex Medications of Medically Complex Children

OBJECTIVES

Parents and caregivers of children with medical complexity (CMC) manage complex medication regimens (CMRs) at home. Parental understanding of CMRs is critical to safe medication administration. Regarding CMR administration, we 1) described the population of CMC receiving CMRs; 2) assessed parental perceived confidence and understanding; and 3) evaluated parental demonstrated understanding.

METHODS

Cross-sectional clinic-based assessment of knowledge and understanding of CMC using CMRs who received primary care in a large pediatric complex care clinic. CMRs were identified by the receipt of ≥1 of the following: 1) ≥10 concurrent medications; 2) ≥1 high-risk medication; or 3) ≥1 extemporaneously compounded medication. Parents reported their perceived confidence and understanding of CMRs, and then demonstrated understanding through 3 medication-related tasks.

RESULTS

Of 156 CMCs, most were <10 years of age (63.5%), white (75%), had neurologic impairment (76.9%), and used a median of 8 medications (IQR, 5-10). Parents were female (76.9%) with a mean age of 38.8 ± 11.5 years, white (69.9%), spoke English (94.2%), and had some college education (82.1%). On 11 confidence and understanding statements, most parents reported a high perceived level of understanding and confidence, with combined agreement or strong agreement ranging between 81.2% and 98.7%. Only 73.1% correctly identified medications taken for specified conditions, 40.4% reported complete dosing parameters, and 54.8% correctly measured 2 different medication doses. Significant differences existed between parental perceived understanding versus the 3 demonstrated tasks (all p < 0.05).

CONCLUSIONS

Substantial opportunities exist to improve medication safety and efficacy in the outpatient, in-home setting including improved medication-specific education and medication-related supports.

Risperidone plasma concentrations are associated with side effects and effectiveness in children and adolescents with autism spectrum disorder

AIM

Risperidone is the most commonly prescribed antipsychotic drug to children and adolescents worldwide, but it is associated with serious side effects, including weight gain. This study assessed the relationship of risperidone and 9-hydroxyrisperidone trough concentrations, maximum concentrations and 24-hour area under the curves (AUCs) with body mass index (BMI) z-scores in children and adolescents with autism spectrum disorder (ASD) and behavioural problems. Secondary outcomes were metabolic, endocrine, extrapyramidal and cardiac side effects and effectiveness.

METHODS

Forty-two children and adolescents (32 males) aged 6-18 years were included in a 24-week prospective observational trial. Drug plasma concentrations, side effects and effectiveness were measured at several time points during follow-up. Relevant pharmacokinetic covariates, including medication adherence and CYP2D6, CYP3A4, CYP3A5 and P-glycoprotein (ABCB1) genotypes, were measured. Nonlinear mixed-effects modelling (NONMEM®) was used for a population pharmacokinetic analysis with 205 risperidone and 205 9-hydroxyrisperidone concentrations. Subsequently, model-based trough concentrations, maximum concentrations and 24-hour AUCs were analysed to predict outcomes using generalized and linear mixed-effects models.

RESULTS

A risperidone two-compartment model combined with a 9-hydroxyrisperidone one-compartment model best described the measured concentrations. Of all the pharmacokinetic parameters, higher risperidone sum trough concentrations best predicted higher BMI z-scores during follow-up (P < .001). Higher sum trough concentrations also predicted more sedation (P < .05), higher prolactin levels (P < .001) and more effectiveness measured with Aberrant Behavior Checklist irritability score (P < .01).

CONCLUSION

Our results indicate a therapeutic window exists, which suggests that therapeutic drug monitoring of risperidone might increase safety and effectiveness in children and adolescents with ASD and behavioural problems.

Treatment-Resistant Depression in Adolescents: Clinical Features and Measurement of Treatment Resistance

Objective: To describe the clinical characteristics of adolescents with antidepressant treatment-resistant major depressive disorder (MDD) and to examine the utility of the Antidepressant Treatment Record (ATR) in categorizing treatment resistance in this population. Methods: Adolescents with treatment-resistant MDD enrolled in an interventional study underwent a baseline evaluation with the ATR, Children's Depression Rating Scale-Revised (CDRS-R), and Clinical Global Impressions-Severity (CGI-S) scales. Demographic and clinical characteristics were examined with regard to ATR-defined level of resistance (level 1 to ≥3) using analysis of variance and χ² tests. Results: In adolescents with treatment-resistant MDD (N = 97), aged 12-21 years, most were female (65%), white (89%), and had recurrent illness (78%). Patients were severely ill (median CGI-S score of 5), had a mean CDRS-R score of 63 ± 10, and 17.5% had been hospitalized for depression-related symptoms. Fifty-two patients were classified as ATR 1, whereas 32 were classified as ATR level 2 and 13 patients as ≥3, respectively. For increasing ATR-defined levels, illness duration increased from 12.0 (range: 1.5-31.9) to 14.8 (range: 1.8-31.7) to 19.5 (range: 2.5-36.2) months and the likelihood of treatment with serotonin norepinephrine reuptake inhibitors (SNRIs) and dopamine norepinephrine reuptake inhibitors (DNRIs) similarly increased (p = 0.006 for both SNRIs and DNRIs) as did the likelihood of treatment with mixed dopamine serotonin receptor antagonists (χ² = 17, p < 0.001). Conclusions: This study underscores the morbidity and chronicity of treatment-resistant MDD in adolescents. The present characterization of related clinical features describes the use of nonselective serotonin reuptake inhibitors in adolescents with treatment-resistant depression and raises the possibility that those with the greatest medication treatment resistance are less likely to have had recurrent episodes. The study also demonstrates the utility of the ATR in categorizing treatment resistance in adolescents with MDD.

Scientific and Regulatory Considerations for an Ontogeny Knowledge Base for Pediatric Clinical Pharmacology

Understanding all aspects of developmental biology, or pediatric ontogeny, that affect drug therapy from the fetus to the adolescent child is the holy grail of pediatric scientists and clinical pharmacologists. The scientific community is now close to being able to tie together the vast amount of information collected on pediatric ontogeny over the past 60 years. An organized knowledge base and new tools would allow us to utilize this information effectively in pediatric drug development.

Orodispersible films containing ball milled aripiprazole-poloxamer®407 solid dispersions

This research aimed at developing ODFs containing an antipsychotic drug - aripiprazole (ARP). ARP, as a BCS II class molecule, requires enhancing its water solubility prior to formulating. Therefore, a solid dispersion of ARP - Poloxamer® 407 was prepared by ball milling, then incorporated into the films. It was found that co-processing led to an over 100-fold increase in drug solubility in comparison with pure drug. Moreover, ODFs with solid dispersion showed faster drug release (>95% below 15 min) and disintegration (<30 s), compared with raw ARP films. These results are believed to be due to the solubilization effect of poloxamer and enhanced wettability of the film. Films containing solid dispersions were found to possess smoother film surfaces and favorable mechanical properties - flexibility and strength. The ODF formulations, prepared by a casting method, were based on three different polymers (Kollicoat® IR, Kollicoat® Protect or PVA). It was found that not only the form of the incorporated drug, but also the type of film-forming polymer had an impact on the analyzed parameters. The use of PVA was beneficial in the film formulation with aripiprazole in comparison to other tested film-forming polymers.

International Coherence of Pediatric Drug Labeling for Drug Safety: Comparison of Approved Labels in Korea and the United States

The objective of this study was to analyze information on pediatric use in Korean drug product labels and compare it with that in US Food and Drug Administration (FDA) labeling information. Prescription information on pediatric use contained in the commonly used drugs’ product labels approved by Korean government was compared with that approved by the FDA. Among the top 50 commonly prescribed drugs, 20 drugs were deemed to have insufficient prescribing information in Korean drug labels. Pediatric prescribing information regarding indication, approved age, formulations, and safety was insufficient in Korean drug labels compared with those in the FDA. Most important, the adverse events frequently reported in Korean children were not sufficiently presented in drug labels. In conclusion, this study highlights the urgent need for the Korean regulatory agency to encourage and accelerate research and development to increase the extent of pediatric prescribing information to be added to drug labels to promote appropriate drug prescribing for children.

Ontogeny and the Application of Pharmacogenomics to Pediatric Drug Development

Drug product labels are important vehicles for conveying the scientific information needed for the safe and effective use of a medicinal product. Increasingly, pharmacogenomic (PGx) information is being incorporated into US Food and Drug Administration-approved product labels. In the majority of cases, the PGx information in labeling is derived from studies in adults. Observed genotype-phenotype relationships in adults may not always be reflective of those in certain pediatric age groups because of the influence of ontogeny. The quantitative data necessary for modeling certain genomic markers in pediatrics is still lacking, and further research focused on generating this is needed. In addition, drug safety research focused on understanding the potential contributions of ontogeny, PGx and other underlying mechanisms to differences in adverse drug reactions between pediatrics and adults is warranted.

Monoclonal Antibodies and Fc-Fusion Proteins for Pediatric Use: Dosing, Immunogenicity, and Modeling and Simulation in Data Submitted to the US Food and Drug Administration

The experience with the use of monoclonal antibodies and Fc-fusion proteins (mAb/Fc) in the pediatric population is limited. The objective of this study is to review those factors impacting the clinical efficacy and product safety of mAb/Fc products in pediatric patients during drug development. We reviewed the list of biologic products in the US Food and Drug Administration's Purple Book as of March 2018 with a focus on mAb/Fc products that are indicated for use in both adults and pediatric patients. Of 68 mAb/Fc products in the Purple Book (excluding biosimilars), 20 products have approved indications in both adults and children. Thirteen products had concurrent approval for both adult and pediatric populations. The sample size of pediatric studies generally ranged from approximately 2% to 70% of the sample size of adult studies with the same indication. In general, pediatric dosing regimens were found to be more based on body weight and weight tiered than the regimens for adults. Modeling and simulation techniques comprised mainly population pharmacokinetic and pharmacodynamic models. A review of the immunogenicity incidence did not reveal any notable difference in the 5 products having data on both pediatric and adult patients. In conclusion, most of the mAb/Fc products have a different weight-based dosing regimen for pediatric patients versus adults. An understanding of the comparative experience in drug development for mAb/Fc products between adult and pediatric patients coupled with the application of advanced modeling and simulation methods should assist future development of new mAb/Fc products for pediatric patients.