Design and conduct of early phase drug studies in children: challenges and opportunities

Conducting Drug Treatment Trials in Children: Opportunities and Challenges

Children were often referred to as "therapeutic orphans" in the past due to different reasons such as ethical, regulatory, economic, scientific, etc., ones. They were exposed to avoidable risks while missing out on therapeutic advances. Pediatric patients have suffered from a lack of scientific and regulatory standards (e.g., proper drug testing, authorization of medicines for their use, etc.), although the pharmaceutical legislative framework, which ensures the high standards of safety, quality, and efficacy of medicinal products for use in adults, was developed primarily in response to past "drug disasters," mainly involving children. The adoption of pediatric regulatory initiatives first in the USA and then in Europe and other countries and regions has significantly changed the worldwide frameworks and permanently changed pediatric drug research and development. This article tries to give various perspectives with historical context, a review of the different challenges and opportunities as well as important stakeholders in pediatric drug development. The pediatric trial networks are probably the most important stakeholder that enables efficient patient recruitment, access to better resource utilization, and global collaboration of different stakeholders necessary for performing quality and well-designed clinical trials.

Paediatric drug development and evaluation: Existing challenges and recommendations

Despite various international regulatory initiatives over the last 20 years, many challenges remain in the field of paediatric drug development and evaluation. Indeed, drug research and development is still focused essentially on adult indications, thereby excluding many paediatric patients, limiting the feasibility of trials and favouring competing developments. Off-label prescribing persists and the development of age-appropriate dosage forms for children remains limited. Against this background, the members of this panel (TR) recommend the launch of multi-partner exchange forums on specific topics in order to focus new drug research and development on the real, unmet medical needs of children and adolescents, and in keeping with the underlying mechanisms of action. Scientific information sharing and cooperation between stakeholders are also essential for defining reference evaluation methods in each medical field. These forums can be organised through existing paediatric facilities and research networks at the French and European level. The latter are specifically dedicated to paediatric research and can facilitate clinical trial implementation and patient enrolment. Moreover, specific grants and public/private partnerships are still needed to support studies on the repositioning of drugs in paediatric indications, and pharmacokinetic studies aimed at defining appropriate dosages. The development of new pharmaceutical forms, better suited for paediatric use, and the promotion of resulting innovations will stimulate future investments. Initiatives to gather observational safety and efficacy data following off-label and/or derogatory early access should also be encouraged to compensate for the lack of information available in these situations. Finally, the creation of Ethics Committees (EC) with a specific "mother-child" advisory expertise should be promoted to ensure that the current regulation (Jardé law in France) is implemented whilst also taking into account the paediatric specificities in medical trials.

Paediatric pharmacotherapy and drug regulation: Moving past the therapeutic orphan

The development of specific drug therapy for children was a paradigm-changing event that transformed paediatric medical practice. However, a series of tragedies involving drug treatment for children resulted in a gap developing between drug regulation and practice, with the majority of drugs used in child healthcare being used off-label, rendering children therapeutic orphans. Over the past two decades changes in drug regulation led by the US Food and Drug Administration and followed by the European Union's European Medicines Agency have led to substantial changes in how new drugs with potential use in children are studied and labelled. While these changes have substantially improved labelling for new drugs, there has been much less progress with older drugs. Although the unique challenges of conducting clinical research in children have been addressed by novel clinical trial designs, many of these innovations have not been translated into approaches accepted for the drug approval process. The regulations applying to the need for paediatric studies currently are only applicable in the United States and the European Union, and there is less impetus for paediatric labelling in other jurisdictions. This impacts on a number of issues beyond labelling, including the availability of child-friendly formulations. Finally, the impact of Brexit on paediatric drug studies in the UK remains unclear and is subject to ongoing negotiations between the UK government and the European Union.

Description of vaccine clinical trials in Africa: a narrative review

Clinical research is important in establishing the effects of health-care interventions. Vaccine clinical trials are to examine the effectiveness and safety of vaccines for the prevention of diseases. Africa has a high burden of infectious diseases such as malaria, tuberculosis, HIV/AIDS, and Ebola virus disease. Here we report a database surveillance study of vaccine-related clinical trials conducted in Africa. An objective is to address and profile vaccine clinical trials conducted in Africa. Data were extracted from the WHO International Clinical Trials Registry Platform on 22 July 2018 and updated on 05 September 2019. We found that 61% of the 377 clinical trials were registered prospectively and 35% registered retrospectively. About 72% of the trials were single-country studies and within the country, most trials (86%) were single-center studies. The proportion of trials involving multiple African countries was 11% and that of trials involving countries outside of Africa was 16%. The biggest funder of the vaccine trials (34%) was industry, followed by governments (25%) and universities (21%). The most studied diseases were malaria (20%), HIV/AIDS (15%), tuberculosis (7%), and Ebola virus disease (6%). Most of the vaccine trials were conducted in adults (42%). The trials ranged from phase I to phase IV, with most of the trials being in phase I (18%) and phase III (18%). The conduct of vaccine clinical trials in Africa seeks to address the disease epidemics faced by the continent. There is a need for more investments from governmental bodies toward vaccine research in Africa. Further, African country collaborations are needed in efforts to find African solutions to the current infectious disease threats faced by the continent.

Oral ibuprofen is superior to oral paracetamol for patent ductus arteriosus in very low and extremely low birth weight infants

Paracetamol (acetaminophen) has been proposed as an alternative medication for closing hemodynamically significant patent ductus arteriosus (PDA). However, the clinical outcomes remain inconclusive in very low birth weight (VLBW) and extremely low birth weight (ELBW) infants.The aim of this study was to compare the efficacy and safety of oral paracetamol and ibuprofen for pharmacological closure of PDA in premature infants from a real-world study.This retrospective study enrolled 255 preterm infants with birthweights of ≤1.5 kg, and echocardiographically confirmed significant PDA. Subjects were classified into 3 groups: Group I (standard-dose ibuprofen group) received 10 mg/kg oral ibuprofen followed by 5 mg/kg/day for 2 days. Group II (high-dose ibuprofen group) received 10 mg/kg/day oral ibuprofen for 3 days. Group III (paracetamol group) received 15 mg/kg/6 h oral paracetamol for 3 days.On day 9 after medication start, PDA closure was achieved in 61 (71.7%) patients assigned to the high-dose ibuprofen group, (63.8%) in the standard-dose ibuprofen group, and 33 (37.9%) of those in the oral paracetamol group (P <.001). Oral standard-dose ibuprofen was more effective than oral paracetamol (P = .001). The ductus closed faster in the high-dose ibuprofen group than in the standard-dose group (median closure time 3.9 ± 1.0 versus 4.4 ± 1.0 days, P = .009). Total bilirubin significantly increased in the high-dose ibuprofen group (P = .02). No gastrointestinal, renal, or hematological adverse effects were reported. Subgroup analyses indicated paracetamol was minimally effective in ELBW infants (PDA closure 13%).This study demonstrated that paracetamol may be a poor medical alternative for PDA management in VLBW and ELBW infants. High dosage ibuprofen was associated with a faster clinical improvement and higher rate of PDA closure.

Improving Diagnostic and Therapeutic Outcomes in Pediatric Brain Tumors

Pediatric brain tumors are the primary cause of cancer-related death during childhood. Unfortunately, the number of primary and metastatic brain tumors is steadily increasing while the mortality rates for many central nervous system (CNS) lesions have remained stagnant. Molecularly defined tumor classes have been added to the most recent 2016 World Health Organization (WHO) Classification System of Central Nervous System Brain Tumors, driving potential new treatments and identifying targets to improve survival for these patients. Focusing on the genetic mutations most commonly seen in the pediatric CNS tumor population provides the ability to better define tumors based on shared molecular characteristics. Consequently, there is the potential for greater efficacy in targeted therapy to treat these identified genetic aberrations. Understanding the growing importance of molecular diagnosis in pediatric CNS tumors is vital to successfully using novel targeted therapies and improving patient outcomes.

Innovative Study Designs Optimizing Clinical Pharmacology Research in Infants and Children

Almost half of recent pediatric trials failed to achieve labeling indications, in large part because of inadequate study design. Therefore, innovative study methods are crucial to optimizing trial design while also reducing the potential harms inherent with drug investigation. Several methods exist to optimize the amount of pharmacokinetic data collected from the smallest possible volume and with the fewest number of procedures, including the use of opportunistic and sparse sampling, alternative and noninvasive matrices, and microvolume assays. In addition, large research networks using master protocols promote collaboration, reduce regulatory burden, and increase trial efficiency for both early- and late-phase trials. Large pragmatic trials that leverage electronic health records can capitalize on central management strategies to reduce costs, enroll patients with rare diseases on a large scale, and augment study generalizability. Further, trial efficiency and safety can be optimized through Bayesian adaptive techniques that permit planned protocol changes based on analyses of prior and accumulated data. In addition to these trial design features, advances in modeling and simulation have paved the way for systems-based and physiologically based models that individualize pediatric dosing recommendations and support drug approval. Last, given the low prevalence of many pediatric diseases, collecting deidentified genetic and clinical data on a large scale is a potentially transformative way to augment clinical pharmacology research in children.

Risk and surrogate benefit for pediatric Phase I trials in oncology: A systematic review with meta-analysis

BACKGROUND

Pediatric Phase I cancer trials are critical for establishing the safety and dosing of anti-cancer treatments in children. Their implementation, however, must contend with the rarity of many pediatric cancers and limits on allowable risk in minors. The aim of this study is to describe the risk and benefit for pediatric cancer Phase I trials.

METHODS AND FINDINGS

Our protocol was prospectively registered in PROSPERO (CRD42015015961). We systematically searched Embase and PubMed for solid and hematological malignancy Phase I pediatric trials published between 1 January 2004 and 1 March 2015. We included pediatric cancer Phase I studies, defined as "small sample size, non‑randomized, dose escalation studies that defined the recommended dose for subsequent study of a new drug in each schedule tested." We measured risk using grade 3, 4, and 5 (fatal) drug-related adverse events (AEs) and benefit using objective response rates. When possible, data were meta-analyzed. We identified 170 studies meeting our eligibility criteria, accounting for 4,604 patients. The pooled overall objective response rate was 10.29% (95% CI 8.33% to 12.25%), and was lower in solid tumors, 3.17% (95% CI 2.62% to 3.72%), compared with hematological malignancies, 27.90% (95% CI 20.53% to 35.27%); p < 0.001. The overall fatal (grade 5) AE rate was 2.09% (95% CI 1.45% to 2.72%). Across the 4,604 evaluated patients, there were 4,675 grade 3 and 4 drug-related AEs, with an average grade 3/4 AE rate per person equal to 1.32. Our study had the following limitations: trials included in our review were heterogeneous (to minimize heterogeneity, we separated types of therapy and cancer types), and we relied on published data only and encountered challenges with the quality of reporting.

CONCLUSIONS

Our meta-analysis suggests that, on the whole, AE and response rates in pediatric Phase I trials are similar to those in adult Phase I trials. Our findings provide an empirical basis for the refinement and review of pediatric Phase I trials, and for communication about their risk and benefit.

Methodological and Ethical Issues in Pediatric Medication Safety Research

In May 2016, the Eshelman School of Pharmacy at The University of North Carolina at Chapel Hill convened the PharmSci conference to address the topic of "methodological and ethical issues in pediatric medication safety research." A multidisciplinary group of experts representing a diverse array of perspectives, including those of the US Food and Drug Administration, children's hospitals, and academia, identified important considerations for pediatric medication safety research and opportunities to advance the field. This executive summary describes current challenges that clinicians and researchers encounter related to pediatric medication safety research and identifies innovative and ethically sound methodologies to address these challenges to improve children's health. This article addresses 5 areas: (1) pediatric drug development and drug trials; (2) conducting comparative effectiveness research in pediatric populations; (3) child and parent engagement on study teams; (4) improving communication with children and parents; and (5) assessing child-reported outcomes and adverse drug events.

How to optimise drug study design: pharmacokinetics and pharmacodynamics studies introduced to paediatricians

OBJECTIVES

In children, there is often lack of sufficient information concerning the pharmacokinetics (PK) and pharmacodynamics (PD) of a study drug to support dose selection and effective evaluation of efficacy in a randomised clinical trial (RCT). Therefore, one should consider the relevance of relatively small PKPD studies, which can provide the appropriate data to optimise the design of an RCT.

METHODS

Based on the experience of experts collaborating in the EU-funded Global Research in Paediatrics consortium, we aimed to inform clinician-scientists working with children on the design of investigator-initiated PKPD studies.

KEY FINDINGS

The importance of the identification of an optimal dose for the paediatric population is explained, followed by the differences and similarities of dose-ranging and efficacy studies. The input of clinical pharmacologists with modelling expertise is essential for an efficient dose-finding study.

CONCLUSIONS

The emergence of new laboratory techniques and statistical tools allows for the collection and analysis of sparse and unbalanced data, enabling the implementation of (observational) PKPD studies in the paediatric clinic. Understanding of the principles and methods discussed in this study is essential to improve the quality of paediatric PKPD investigations, and to prevent the conduct of paediatric RCTs that fail because of inadequate dosing.

Prediction of serum theophylline concentrations and cytochrome P450 1A2 activity by analyzing urinary metabolites in preterm infants

AIMS

The purpose of this study was to explore clinical markers reflecting developmental changes in drug clearance by preterm infants.

METHODS

Preterm infants administered aminophylline or theophylline to treat apnoea of prematurity were enrolled in this study. Trough and one of 2 h, 4 h or 6 h post-dose blood samples and urine samples were collected during steady state, to determine the concentrations of theophylline and its targeted metabolites. CYP1A2*1C and CYP1A2*1F genotypes were analyzed. Total, renal and nonrenal clearances of theophylline were calculated, and cytochrome P450 1A2 (CYP1A2) activity was obtained from the ratio of 1-methyluric acid and 3-methylxanthine to theophylline in urine. Multiple linear regression analysis was performed to evaluate the relationships between theophylline clearance and the clinical characteristics of preterm infants.

RESULTS

A total of 152 samples from 104 preterm infants were analyzed. A strong association between the serum trough and urine theophylline concentrations was found (P < 0.001). Total, renal and nonrenal clearances of theophylline were 0.50 ± 0.29 ml kg^-1  min^-1 , 0.16 ± 0.06 ml kg^-1  min^-1 and 0.34 ± 0.28 ml kg^-1  min^-1 , respectively. CYP1A2 activity correlated positively with the postnatal age and postmenstrual age. However, CYP1A2 genotype was not associated with CYP1A2 activity, which was significantly associated with nonrenal clearance. CYP1A2 activity, postnatal age , weight and 24-h urine output were significantly associated with total theophylline clearance.

CONCLUSIONS

CYP1A2 activity can be monitored using noninvasive random urine samples, and it can be used to assess developmental changes in theophylline clearance by preterm infants.

Design and conduct of early phase drug studies in children: challenges and opportunities

It has historically been very difficult to conduct early phase drug studies in children for a number of reasons related to ethics, acceptability, rarity, standardization, end points, safety, dosing and feasibility. Over the past decade there have been a number of developments including novel clinical trial design, in silico pharmacology and microdosing that have significantly enhanced the ability of investigators to conduct early phase drug studies in children. While the evolution of drug therapy is creating a series of new challenges, there has never been a better time for conducting drug studies in children.