Innovative Study Designs Optimizing Clinical Pharmacology Research in Infants and Children

Advances in pediatric acute kidney injury pharmacology and nutrition: a report from the 26th Acute Disease Quality Initiative (ADQI) consensus conference

BACKGROUND

In the past decade, there have been substantial advances in our understanding of pediatric AKI. Despite this progress, large gaps remain in our understanding of pharmacology and nutritional therapy in pediatric AKI.

METHODS

During the 26th Acute Disease Quality Initiative (ADQI) Consensus Conference, a multidisciplinary group of experts reviewed the evidence and used a modified Delphi process to achieve consensus on recommendations for gaps and advances in care for pharmacologic and nutritional management of pediatric AKI. The current evidence as well as gaps and opportunities were discussed, and recommendations were summarized.

RESULTS

Two consensus statements were developed. (1) High-value, kidney-eliminated medications should be selected for a detailed characterization of their pharmacokinetics, pharmacodynamics, and pharmaco-"omics" in sick children across the developmental continuum. This will allow for the optimization of real-time modeling with the goal of improving patient care. Nephrotoxin stewardship will be identified as an organizational priority and supported with necessary resources and infrastructure. (2) Patient-centered outcomes (functional status, quality of life, and optimal growth and development) must drive targeted nutritional interventions to optimize short- and long-term nutrition. Measures of acute and chronic changes of anthropometrics, body composition, physical function, and metabolic control should be incorporated into nutritional assessments.

CONCLUSIONS

Neonates and children have unique metabolic and growth parameters compared to adult patients. Strategic investments in multidisciplinary translational research efforts are required to fill the knowledge gaps in nutritional requirements and pharmacological best practices for children with or at risk for AKI.

Food and Drug Administration Public Workshop Summary-Development Considerations of Antifungal Drugs to Address Unmet Medical Need

Pressing challenges in the treatment of invasive fungal infections (IFIs) include emerging and rare pathogens, resistant/refractory infections, and antifungal armamentarium limited by toxicity, drug-drug interactions, and lack of oral formulations. Development of new antifungal drugs is hampered by the limitations of the available diagnostics, clinical trial endpoints, prolonged trial duration, difficulties in patient recruitment, including subpopulations (eg, pediatrics), and heterogeneity of the IFIs. On 4 August 2020, the US Food and Drug Administration convened a workshop that included IFI experts from academia, industry, and other government agencies to discuss the IFI landscape, unmet need, and potential strategies to facilitate the development of antifungal drugs for treatment and prophylaxis. This article summarizes the key topics presented and discussed during the workshop, such as incentives and research support for drug developers, nonclinical development, clinical trial design challenges, lessons learned from industry, and potential collaborations to facilitate antifungal drug development.

Randomized controlled trial data for successful new drug application for rare diseases in the United States

BACKGROUND

Randomized controlled trial (RCT) data have important implications in drug development. However, the feasibility and cost of conducting RCTs lower the motivation for drug development, especially for rare diseases. We investigated the potential factors associated with the need for RCTs in the clinical data package for new drug applications for rare diseases in the United States (US). This study focused on 233 drugs with orphan drug designations approved in the US between April 2001 and March 2021. Univariable and multivariable logistic regression analyses were conducted to investigate the association between the presence or absence of RCTs in the clinical data package for new drug applications.

RESULTS

Multivariable logistic regression analysis showed that the severity of the disease outcome (odds ratio [OR] 5.63, 95% confidence interval [CI] 2.64-12.00), type of drug usage (odds ratio [OR] 2.95, 95% confidence interval [CI] 1.80-18.57), and type of primary endpoint (OR 5.57, 95% CI 2.57-12.06) were associated with the presence or absence of RCTs.

CONCLUSIONS

Our results indicated that the presence or absence of RCT data in the clinical data package for successful new drug application in the US was associated with three factors: severity of disease outcome, type of drug usage, and type of primary endpoint. These results highlight the importance of selecting target diseases and potential efficacy variables to optimize orphan drug development.

Randomized Controlled Trial Data for New Drug Application for Rare Diseases in Japan

BACKGROUND

High-quality evidence is often not obtained in the clinical trials of rare diseases because these trials tend to be smaller in size and non-controlled. We investigated the potential factors associated with the need for randomized controlled trials (RCTs) in the clinical data package for new drug applications for rare diseases in Japan.

METHODS

This study focused on 130 drugs with orphan drug designation approved in Japan between April 2004 and March 2020.

RESULTS

Multivariable regression analysis showed that the prevalence (odds ratio [OR] 3.21, 95% confidence interval [CI] 1.18-8.6) and the type of primary endpoint (OR 6.66, 95% CI 2.41-18.37) were associated with the need for RCTs in the clinical data package in Japan.

CONCLUSIONS

Our findings highlight the importance of adequate understanding of the target disease in new drug development for rare diseases.

Early brain activity: Translations between bedside and laboratory

Neural activity is both a driver of brain development and a readout of developmental processes. Changes in neuronal activity are therefore both the cause and consequence of neurodevelopmental compromises. Here, we review the assessment of neuronal activities in both preclinical models and clinical situations. We focus on issues that require urgent translational research, the challenges and bottlenecks preventing translation of biomedical research into new clinical diagnostics or treatments, and possibilities to overcome these barriers. The key questions are (i) what can be measured in clinical settings versus animal experiments, (ii) how do measurements relate to particular stages of development, and (iii) how can we balance practical and ethical realities with methodological compromises in measurements and treatments.

Neurology's vital role in preventing unnecessary and potentially harmful pediatric studies

INTRODUCTION

Regulatory authorities recognize two human populations: adults and children defined as <18 years. For drug approval, they demand separate studies. But humans mature slowly during puberty. The 18^th birthday is an administrative limit that does not correspond to a physiological change. Separate drug approval before/after the 18^th birthday reflects the children-are-therapeutic-orphans concept that emerged after 1962. The Food and Drug Administration (FDA) has backed away from this concept for antiepileptic drugs, but sticks to it in other areas. In contrast, the European Medicines Agency (EMA) is continuously expanding its demand for "pediatric" studies. Parents hesitate increasingly to let their children participate in questionable studies.

AREAS COVERED

Neurologists challenge the children-are-therapeutic-orphans mantra. Young patients do not need separate proof of efficacy & safety, but appropriate dosing recommendations. Minors should be treated as human beings, instead of being abused in questionable studies.

EXPERT OPINION

Young patients with multiple sclerosis and other neurological diseases deserve studies with therapeutic intentions. "Pediatric" careers have emerged in academia, regulatory authorities, and pharmaceutical companies. Institutional Review Boards/ Ethics Committees should suspend questionable "pediatric" studies and reject newly submitted ones. The medical professions should distance themselves from questionable "pediatric" research that reflects massive conflicts of interest.

Review of Scavenged Sampling for Sustainable Therapeutic Drug Monitoring: Do More With Less

PURPOSE

Innovative and sustainable sampling strategies for bioanalytical quantification of drugs and metabolites have gained considerable interest. Scavenging can be stratified as a sustainable sampling strategy using residual material because it aligns with the green principles of waste reduction and sampling optimization. Scavenged sampling includes all biological fluids' (eg, blood, liquor, and urine) leftover from standard clinical care. This review elaborates on the past and current landscape of sustainable sampling within therapeutic drug monitoring, with a focus on scavenged sampling.

METHODS

In February 2021, 4 databases were searched to assess the literature on the clinical use of innovative and sustainable sampling techniques without applying publication date restrictions. Studies reporting the clinical use of scavenged blood sampling and bridging studies of scavenged sampling and normal blood sampling were eligible for inclusion.

RESULTS

Overall, 19 eligible studies concerning scavenged sampling were identified from 1441 records. Scavenged sampling is mainly applied in the pediatric population, although other patient groups may benefit from this strategy. The infrastructure required for scavenged sampling encounters several challenges, including logistic hurdles, storage and handling conditions, and documentation errors. A workflow is proposed with identified opportunities that guide the implementation of scavenged sampling.

CONCLUSIONS

This review presents current evidence on the clinical use of scavenged sampling strategies. Scavenged sampling can be a suitable approach for drug quantification to improve dosage regimens, perform pharmacokinetic studies, and explore the value of therapeutic drug monitoring without additional sample collection.

Improving clinical paediatric research and learning from COVID-19: recommendations by the Conect4Children expert advice group

BACKGROUND

The COVID-19 pandemic has had a devastating impact on multiple aspects of healthcare, but has also triggered new ways of working, stimulated novel approaches in clinical research and reinforced the value of previous innovations. Conect4children (c4c, www.conect4children.org ) is a large collaborative European network to facilitate the development of new medicines for paediatric populations, and is made up of 35 academic and 10 industry partners from 20 European countries, more than 50 third parties, and around 500 affiliated partners.

METHODS

We summarise aspects of clinical research in paediatrics stimulated and reinforced by COVID-19 that the Conect4children group recommends regulators, sponsors, and investigators retain for the future, to enhance the efficiency, reduce the cost and burden of medicines and non-interventional studies, and deliver research-equity.

FINDINGS

We summarise aspects of clinical research in paediatrics stimulated and reinforced by COVID-19 that the Conect4children group recommends regulators, sponsors, and investigators retain for the future, to enhance the efficiency, reduce the cost and burden of medicines and non-interventional studies, and deliver research-equityWe provide examples of research innovation, and follow this with recommendations to improve the efficiency of future trials, drawing on industry perspectives, regulatory considerations, infrastructure requirements and parent-patient-public involvement. We end with a comment on progress made towards greater international harmonisation of paediatric research and how lessons learned from COVID-19 studies might assist in further improvements in this important area.

Precision Medicine: Towards Individualized Dosing in Pediatric Rheumatology

Despite an increase in the number of available therapeutics, many children with rheumatic disease continue to experience active inflammatory disease and treatment failure. One reason for treatment failure is the lack of dosing paradigms to account for the wide between-patient variability in drug pharmacokinetics because of developmental changes or genetic polymorphisms that effect drug absorption, distribution, metabolism, and elimination. This review highlights several strategies to optimize dosing for biologic and nonbiologic disease-modifying antirheumatic drugs, including therapeutic drug monitoring, pharmacogenomics, and the use of pharmacokinetic/pharmacodynamic modeling.

Model-Informed Pediatric Drug Development: Application of Pharmacometrics to Define the Right Dose for Children

One of the biggest challenges in pediatric drug development is defining a safe and effective dose in pediatric populations, which span across a wide age and development range from neonates to adolescents. Model-informed drug development approaches are particularly suited to address knowledge gaps including data leveraging to increase the success of pediatric studies. Considering the often limited number of patients available for study and logistic difficulties to collect the necessary data in pediatric populations, the application of pharmacometrics and modeling and simulation techniques can improve clinical trial efficiency, increase the probability of regulatory success, and optimize therapeutic individualization in support of dedicated trials. This review describes the state of pediatric model-informed drug development to define the right dose for children and provides suggestions for future development.

Drug Safety in Translational Paediatric Research: Practical Points to Consider for Paediatric Safety Profiling and Protocol Development: A Scoping Review

Translational paediatric drug development includes the exchange between basic, clinical and population-based research to improve the health of children. This includes the assessment of treatment related risks and their management. The objectives of this scoping review were to search and summarise the literature for practical guidance on how to establish a paediatric safety specification and its integration into a paediatric protocol. PubMed, Embase, Web of Science, and websites of regulatory authorities and learned societies were searched (up to 31 December 2020). Retrieved citations were screened and full texts reviewed where applicable. A total of 3480 publications were retrieved. No article was identified providing practical guidance. An introduction to the practical aspects of paediatric safety profiling and protocol development is provided by combining health authority and learned society guidelines with the specifics of paediatric research. The paediatric safety specification informs paediatric protocol development by, for example, highlighting the need for a pharmacokinetic study prior to a paediatric trial. It also informs safety related protocol sections such as exclusion criteria, safety monitoring and risk management. In conclusion, safety related protocol sections require an understanding of the paediatric safety specification. Safety data from carefully planned paediatric research provide valuable information for children, parents and healthcare providers.

Study factors associated with the incompletion of clinical trials that include pediatric patients: a retrospective analysis of the European Clinical Trials Database and a lesson from the European region

Background

Incomplete clinical trials for pediatric drug development result in a lack of adequate scientific evidence for providing appropriate medication to pediatric populations; this is especially true for Japan. Thus, using the European Clinical Trials Database (EudraCT), this study aimed to identify the factors related to the study design and administration that lead to incompletion of clinical trials that included pediatric patients.

Methods

We focused on clinical trials that included patients under the age of 18 registered in the database, named as the European Clinical Trials Database between January 1, 2014, and December 31, 2018. Two groups of trials were identified: “all cases completed” and “not all cases completed,” reflecting whether they were completed in all participating countries/regions or not. To identify the factors of the occurrence of “not all cases completed,” a logistic regression analysis was performed to calculate the odds ratios and 95% confidence intervals. In total, 142 clinical trials (95 “all cases completed” and 47 “not all cases completed”) were analyzed.

Results

The logistic regression analysis showed the number of countries in which a clinical trial was conducted to be the only significant factor (odds ratio: 1.3; 95% confidence interval: 1.1-1.5); this was identified as the primary factor for the occurrence of “not all cases completed” in the clinical trials that included pediatric patients.

Conclusion

Our findings suggest that the feasibility of clinical trials that include pediatric patients, such as whether the countries in which the trial is to be conducted are suitable, must be considered prior to the trial.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05143-6.

Clinical pharmacology and dosing regimen optimization of neonatal opioid withdrawal syndrome treatments

In this paper, we review the management of neonatal opioid withdrawal syndrome (NOWS) and clinical pharmacology of primary treatment agents in NOWS, including morphine, methadone, buprenorphine, clonidine, and phenobarbital. Pharmacologic treatment strategies in NOWS have been mostly empirical, and heterogeneity in dosing regimens adds to the difficulty of extrapolating study results to broader patient populations. As population pharmacokinetics (PKs) of pharmacologic agents in NOWS become more well‐defined and knowledge of patient‐specific factors affecting treatment outcomes continue to accumulate, PK/pharmacodynamic modeling and simulation will be powerful tools to aid the design of optimal dosing regimens at the patient level. Although there is an increasing number of clinical trials on the comparative efficacy of treatment agents in NOWS, here, we also draw attention to the importance of optimizing the dosing regimen, which can be arguably equally important at identifying the optimal treatment agent.

Pharmacometric Evaluation of Umbilical Cord Blood Concentration-Based Early Initiation of Treatment in Methadone-Exposed Preterm Neonates

In methadone-exposed preterm neonates, early identification of those at risk of severe neonatal abstinence syndrome (NAS) and use of a methadone dosing regimen that can provide effective and safe drug exposure are two important aspects of optimal care. To this end, we reviewed 17 methadone dosing recommendations in the international guidelines and literature and explored their variability in key dosing strategies. We selected three of the reviewed dosing regimens for their pharmacokinetics (PK) characteristics and their exposure-response relationship in three gestational age groups of preterm neonates (28, 32 and 36 gestational age weeks) at risk for development of severe NAS (defined as an umbilical cord methadone concentration of ≤60 ng/mL, following fetal exposure). We applied early (12 h after birth) vs. typical (36 h after birth) initiation of treatment. We observed that use of universally recommended dosing regimens in preterm neonates can result in under- or over-exposure. Use of a PK-guided dosing regimen resulted in effective target exposures within 24 h after birth with early initiation of treatment (12 h after birth). Future prospective studies should explore the incorporation of umbilical cord methadone concentrations for early identification of preterm neonates at risk of developing severe NAS and investigate the use of a PK-guided methadone dosing regimen, so that treatment failure, prolonged length of stay and opioid over-exposure can be avoided.

Pregabalin Population Pharmacokinetic and Exposure-Response Analyses for Focal Onset Seizures in Children (4-16 years) and Adults, to Support Dose Recommendations in Children

Pregabalin is approved in multiple countries as adjunctive therapy for adult patients with focal onset seizures (FOS; previously termed partial onset seizures). This study used population pharmacokinetic (PK) and exposure–response (E‐R) analyses from pooled pregabalin concentration and efficacy data to compare pregabalin exposure and E‐R relationships in pediatric and adult patients with FOS, to support pediatric dosage recommendations. A one‐compartment disposition model was used, with first‐order absorption and body surface area‐normalized creatinine clearance on clearance. Individual pregabalin average steady‐state concentrations were predicted and used in an E‐R analysis of efficacy. The E‐R relationship of pregabalin was similar in pediatric (4–16 years) and adult patients with FOS after accounting for differences in baseline natural log‐transformed 28‐day seizure rate and placebo effect. Population PK simulations showed that children aged 4–16 years and weighing ≥ 30 kg required pregabalin 2.5–10 mg/kg/day to achieve similar pregabalin exposure at steady‐state to adult patients receiving the approved doses of 150–600 mg/day. For children 4–16 years weighing < 30 kg, a higher pregabalin dose of 3.5–14 mg/kg/day was required to achieve equivalent exposure at steady‐state. The results support the dosage guidance provided in the pregabalin prescribing label, whereby pediatric patients (4–16 years) weighing < 30 kg should receive a 40% higher pregabalin dose (per kg of body weight) than patients weighing ≥ 30 kg to achieve similar exposure. Our combined modeling approach may provide guidance for future extrapolation assessment from adult to pediatric patients.

Exposure-Response Assessment in Pediatric Drug Development Studies Submitted to the US Food and Drug Administration

Exposure-response (E-R) modeling provides a quantitative tool to leverage adult data to support pediatric trial design and drug approval. The pediatric E-R studies submitted to US Food and Drug Administration (FDA) between 2007 and 2018 were surveyed in the context of various types of trial designs supporting drug approval in the pediatric population. The applications of E-R evaluation in pediatric drug development programs are mainly focused on three areas: (i) supporting pediatric extrapolation when the E-R relationships are similar between the pediatric and adult populations; (ii) dose selection to balance the risk-benefit profile based on the change in efficacy and safety response with different exposure levels; and (iii) approval of a new formulation, new dosing regimen, or new route of administration, where E-R evaluation helps quantify the change in clinical response between the old and new strategies. E-R modeling will continue to play an expanded role in pediatric drug development in the future.

Pediatric Clinical Endpoint and Pharmacodynamic Biomarkers: Limitations and Opportunities

Medical research in children typically lags behind that of adult research in both quantity and quality. The conduct of rigorous clinical trials in children can raise ethical concerns because of children's status as a 'vulnerable' population. Moreover, carrying out studies in pediatrics also requires logistical considerations that rarely occur with adult clinical trials. Due to the relatively smaller number of pediatric studies to support evidence-based medicine, the practice of medicine in children is far more reliant upon expert opinion than in adult medicine. Children are at risk of not receiving the same level of benefits from precision medicine research, which has flourished with new technologies capable of generating large amounts of data quickly at an individual level. Although progress has been made in pediatric pharmacokinetics, which has led to safer and more effective dosing, gaps in knowledge still exists when it comes to characterization of pediatric disease and differences in pharmacodynamic response between children and adults. This review highlights three specific therapeutic areas where biomarker development can enhance precision medicine in children: asthma, type 2 diabetes mellitus, and pain. These 'case studies' are meant to update the reader on biomarkers used currently in the diagnosis and treatment of these conditions, and their shortcomings within a pediatric context. Current research on surrogate endpoints and pharmacodynamic biomarkers in the above therapeutic areas will also be described. These cases highlight the current lack in pediatric specific surrogate endpoints and pharmacodynamic biomarkers, as well as the research presently being conducted to address these deficiencies. We finally briefly highlight other therapeutic areas where further research in pediatric surrogate endpoints and pharmacodynamic biomarkers can be impactful to the care of children.

Orphan drugs: major development challenges at the clinical stage

Biotechnology has provided powerful tools to assist in research and development (R&D) for rare diseases. However, orphan drug development presents several major challenges and obstacles, such as low disease prevalence, disease severity, small and heterogeneous patient populations, difficulties in patient recruitment, and limited knowledge of the natural history of disease, among others. Several strategies can be used to plan for and overcome these clinical and regulatory challenges, namely improved clinical trial design, improved patient recruitment, and closer collaboration with the regulatory authorities and with patient associations. As growth in the orphan drug market is expected over the next few years, improving its relevance in the global pharmaceutical market, further challenges might present themselves in the development of orphan drugs.