2024

Adaptive designs in clinical trials: a systematic review-part I BMC Medical Research Methodology, 04 October 2024

Background: Adaptive designs (ADs) are intended to make clinical trials more flexible, offering efficiency and potentially cost-saving benefits. Despite a large number of statistical methods in the literature on different adaptations to trials, the characteristics, advantages and limitations of such designs remain unfamiliar to large parts of the clinical and research community. This systematic review provides an overview of the use of ADs in published clinical trials (Part I). A follow-up (Part II) will compare the application of AD in trials in adult and pediatric studies, to provide real-world examples and recommendations for the child health community.

Methods: Published studies from 2010 to April 2020 were searched in the following databases: MEDLINE (Ovid), Embase (Ovid), and International Pharmaceutical Abstracts (Ovid). Clinical trial protocols, reports, and a secondary analyses using AD were included. We excluded trial registrations and interventions other than drugs or vaccines to align with regulatory guidance. Data from the published literature on study characteristics, types of adaptations, statistical analysis, stopping boundaries, logistical challenges, operational considerations and ethical considerations were extracted and summarized herein.

Results: Out of 23,886 retrieved studies, 317 publications of adaptive trials, 267 (84.2%) trial reports, and 50 (15.8%) study protocols), were included. The most frequent disease was oncology (168/317, 53%). Most trials included only adult participants (265, 83.9%),16 trials (5.4%) were limited to only children and 28 (8.9%) were for both children and adults, 8 trials did not report the ages of the included populations. Some studies reported using more than one adaptation (there were 390 reported adaptations in 317 clinical trial reports). Most trials were early in drug development (phase I, II (276/317, 87%). Dose-finding designs were used in the highest proportion of the included trials (121/317, 38.2 %). Adaptive randomization (53/317, 16.7%), with drop-the-losers (or pick-the-winner) designs specifically reported in 29 trials (9.1%) and seamless phase 2-3 design was reported in 27 trials (8.5%). Continual reassessment methods (60/317, 18.9%) and group sequential design (47/317, 14.8%) were also reported. Approximately two-thirds of trials used frequentist statistical methods (203/309, 64%), while Bayesian methods were reported in 24% (75/309) of included trials.

Conclusion: This review provides a comprehensive report of methodological features in adaptive clinical trials reported between 2010 and 2020. Adaptation details were not uniformly reported, creating limitations in interpretation and generalizability. Nevertheless, implementation of existing reporting guidelines on ADs and the development of novel educational strategies that address the scientific, operational challenges and ethical considerations can help in the clinical trial community to decide on when and how to implement ADs in clinical trials.

Part II: Adaptive designs in pediatric clinical trials: specific examples, comparison with adult trials and a discussion for the child health community Preprint, 10 January 2024

Background: In Part I of this review, we outlined the study characteristics and methodologies utilized in adaptive clinical trials reported in the literature from 2010–2020. Herein, the second part of this analysis presents a secondary analysis of the trials captured within this timeframe that enrolled children.

Methods: This analysis seeks to generate an evidence base that can inform practical recommendations that can shape the design, ethical considerations, and training on methods and reporting for pediatric adaptive design (AD) trials. We performed a secondary analysis of 43 AD trials involving children and compared the study characteristics with those of adult AD trials.

Results: There were one to five arms in these pediatric AD trials, with the most commonly reported adaptive methods being dose modifications (20/43, 46.5%) in dose-finding trials, followed by continual reassessment method (CRM), a model-based Bayesian design, reported in 20 studies (46.5%), and adaptive randomization (9/43, 20.9%). The frequentist framework (68.8%) was most commonly used for statistical analysis. Reporting indicated a lack of patient and parent engagement with clinicians and scientists during the clinical trial (CT) planning process and was only reported in 1 of the reviewed studies (1/43, 2.32%).

Conclusion: We reviewed examples of the most common types of adaptive designs used in pediatric trials and compared the methods used with adults’ trials. Against this background, we provide an overview of the different statistical approaches used and highlight the ethical considerations. The results of this review could serve as a reference for the development of guidelines and training materials to guide clinical researchers and trialists in the use of pediatric adaptive clinical trials.

2019

Reporting of data monitoring committees and adverse events in paediatric trials: a descriptive analysis BMJ Paediatrics Open, 18 February 2019

Objectives: For 300 paediatric trials, we evaluated the reporting of: a data monitoring committee (DMC); interim analyses, stopping rules and early stopping; and adverse events and harm-related endpoints.

Methods: For this cross-sectional evaluation, we randomly selected 300 paediatric trials published in 2012 from the Cochrane Central Register of Controlled Trials. We collected data on the reporting of a DMC; interim analyses, stopping rules and early stopping; and adverse events and harm-related endpoints. We reported the findings descriptively and stratified by trial characteristics.

Results: Eighty-five (28%) of the trials investigated drugs, and 18% (n=55/300) reported a DMC. The reporting of a DMC was more common among multicentre than single centre trials (n=41/132, 31% vs n=14/139, 10%, p<0.001) and industry-sponsored trials compared with those sponsored by other sources (n=16/50, 32% vs n=39/250, 16%, p=0.009). Trials that reported a DMC enrolled more participants than those that did not (median [range]): 224 (10-60480) vs 91 (10-9528) (p<0.001). Only 25% of these trials reported interim analyses, and 42% reported stopping rules. Less than half (n=143/300, 48%) of trials reported on adverse events, and 72% (n=215/300) reported on harm-related endpoints. Trials that reported a DMC compared with those that did not were more likely to report adverse events (n=43/55, 78% vs 100/245, 41%, p<0.001) and harm-related endpoints (n=52/55, 95% vs. 163/245, 67%, p<0.001). Only 32% of drug trials reported a DMC; 18% and 19% did not report on adverse events or harm-related endpoints, respectively.

Conclusions: The reporting of a DMC was infrequent, even among drug trials. Few trials reported stopping rules or interim analyses. Reporting of adverse events and harm-related endpoints was suboptimal.

Keywords: data collection; ethics; general paediatrics.

Improving outcome reporting in clinical trial reports and protocols: study protocol for the Instrument for reporting Planned Endpoints in Clinical Trials (InsPECT) Trials, 06 March 2019

Background: Inadequate and poor quality outcome reporting in clinical trials is a well-documented problem that impedes the ability of researchers to evaluate, replicate, synthesize, and build upon study findings and impacts evidence-based decision-making by patients, clinicians, and policy-makers. To facilitate harmonized and transparent reporting of outcomes in trial protocols and published reports, the Instrument for reporting Planned Endpoints in Clinical Trials (InsPECT) is being developed. The final product will provide unique InsPECT extensions to the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) and CONSORT (Consolidated Standards of Reporting Trials) reporting guidelines.

Methods: The InsPECT SPIRIT and CONSORT extensions will be developed in accordance with the methodological framework created by the EQUATOR (Enhancing the Quality and Transparency of Health Research Quality) Network for reporting guideline development. Development will consist of (1) the creation of an initial list of candidate outcome reporting items synthesized from expert consultations and a scoping review of existing guidance for reporting outcomes in trial protocols and reports; (2) a three-round international Delphi study to identify additional candidate items and assess candidate item importance on a 9-point Likert scale, completed by stakeholders such as trial report and protocol authors, systematic review authors, biostatisticians and epidemiologists, reporting guideline developers, clinicians, journal editors, and research ethics board representatives; and (3) an in-person expert consensus meeting to finalize the set of essential outcome reporting items for trial protocols and reports, respectively. The consensus meeting discussions will be independently facilitated and informed by the empirical evidence identified in the primary literature and through the opinions (aggregate rankings and comments) collected via the Delphi study. An integrated knowledge translation approach will be used throughout InsPECT development to facilitate implementation and dissemination, in addition to standard post-development activities.

Discussion: InsPECT will provide evidence-informed and consensus-based standards focused on outcome reporting in clinical trials that can be applied across diverse disease areas, study populations, and outcomes. InsPECT will support the standardization of trial outcome reporting, which will maximize trial usability, reduce bias, foster trial replication, improve trial design and execution, and ultimately reduce research waste and help improve patient outcomes.

2018

Pharmacokinetic studies in children: recommendations for practice and research Arch Dis Child, 19 April 2018

Optimising the dosing of medicines for neonates and children remains a challenge. The importance of pharmacokinetic (PK) and pharmacodynamic (PD) research is recognised both in medicines regulation and paediatric clinical pharmacology, yet there remain barriers to undertaking high-quality PK and PD studies. While these studies are essential in understanding the dose–concentration–effect relationship and should underpin dosing recommendations, this review examines how challenges affecting the design and conduct of paediatric pharmacological studies can be overcome using targeted pharmacometric strategies. Model-based approaches confer benefits at all stages of the drug life-cycle, from identifying the first dose to be used in children, to clinical trial design, and optimising the dosing regimens of older, off-patent medications. To benefit patients, strategies to ensure that new PK, PD and trial data are incorporated into evidence-based dosing recommendations are needed. This review summarises practical strategies to address current challenges, particularly the use of model-based (pharmacometric) approaches in study design and analysis. Recommendations for practice and directions for future paediatric pharmacological research are given, based on current literature and our joint international experience. Success of PK research in children requires a robust infrastructure, with sustainable funding mechanisms at its core, supported by political and regulatory initiatives, and international collaborations. There is a unique opportunity to advance paediatric medicines research at an unprecedented pace, bringing the age of evidence-based paediatric pharmacotherapy into sight.

Trial registration in pediatric surgery trials Journal of Pediatric Surgery, 27 June 2018

Background: Prospective clinical trial registration serves to increase transparency and to mitigate selective reporting bias. An assessment of adult surgical trials revealed poor trial registration practice with incomplete provision of information in registries and inconsistent information in the corresponding publication. The extent and completeness of pediatric surgical trial registration are unknown. We aimed to determine the proportion and adequacy of clinical trial registration in pediatric surgery trials published in 2014.

Methods: Using sensitive search strategies in MEDLINE, abstracts and full-texts of prospective pediatric intervention studies published in 2014 were screened in duplicate. Pediatric surgical trials were included. Clinical trial registration numbers obtained from publications were searched in trial registries. Data were extracted based on WHO 20-item minimum data set to determine the completeness of registration data. The proportion of registered trials was recorded and registration data were compared to reported data in the corresponding publication.

Results: Our search and abstract screening identified 3375 articles for full text review. Following coding, a total of 54 pediatric surgical trials were included and analyzed; 28% (15/54) of which published a registration number. In trials which reported a registration number, 40% (6/15) were retrospectively registered and 40% (6/15) had made changes to their registered primary and/or secondary outcome measures. One included published trial reported an incorrect registration number.

Conclusions: Analysis of pediatric surgery trials published in 2014 revealed a poor prospective trial registration rate and incomplete registration data. Our study supports future initiatives for improved registration behaviors in pediatric surgery trials to ensure high-quality, transparent, reproducible evidence is generated.

Considerations for adaptive design in pediatric clinical trials: study protocol for a systematic review, mixed-methods study, and integrated knowledge translation plan Trials, 19 October 2018

Background: Although children have historically been excluded from clinical trials (CTs), many require medicines tested and approved in CTs, forcing health care providers to treat their pediatric patients based on extrapolated data. Unfortunately, traditional randomized CTs can be slow and resource-intensive, and they often require multi-center collaboration. However, an adaptive design (AD) framework for CTs could be used to increase the efficiency of pediatric CTs by incorporating prospectively planned modifications to CT methods without undermining the integrity or validity of the study. There are many possible adaptations, but each will have ethical, logistical, and statistical implications. It remains unclear which adaptations (or combinations thereof) will lead to real-world improvements in pediatric CT efficiency. This study will identify, evaluate, and synthesize the various regulatory, ethical, logistical, and statistical considerations and emerging issues of AD in CTs that could be used to evaluate the use of drugs in children.

Methods/design: Following the development of a peer-reviewed search strategy, a systematic review on AD in CTs will be conducted. Data on regulatory, ethical, logistic, and statistical considerations as well as population and trial design characteristics will be synthesized. A mixed-methods study including surveys and focus groups with regulators, research ethics board members, biostatisticians, clinicians, and scientists, as well as representatives from patient groups and the public will evaluate the opportunities and challenges in applying AD in trials enrolling children and propose recommendations on best practices.

Discussion: This study will deliver practical recommendations on the use of AD in pediatric CTs. Collaboration and consultation with national and global partners will ensure that our results meet the needs of researchers, regulators, and patients, both locally and globally, and that they remain current and relevant by engaging a wide variety of stakeholders. Overall, this research will enrich the knowledge base regarding if, how, and when AD can be used to answer research questions with fewer resources while still meeting the highest ethical standards and regulatory requirements for CTs. In turn, this will result in increased high-quality clinical research needed by health care providers so they have access to appropriate, population-specific evidence regarding the safe and effective use of medicines in children.

Consent and recruitment: the reporting of paediatric trials published in 2012 BMJ Paediatrics Open, 26 November 2018

Objectives: We evaluated 300 paediatric trials to determine: the consent and recruitment strategies used, who trial information was targeted to, how incentives were used and if they achieved their recruitment targets.

Methods: For this cross-sectional evaluation, we searched the Cochrane Central Register of Controlled Trials for paediatric trials published in 2012 and randomly selected 300 that reported on outcomes for participants aged ≤21 years. We collected data on consent and recruitment procedures for each trial and undertook descriptive analyses in SPSS statistics V.23.

Results: All but one trial (99.7%) used a standard recruitment strategy. Most (92%) trials reported that consent was obtained but only 13% reported who obtained consent. Two-thirds (65%) of trials included school-aged participants, and of these 68% reported obtaining assent. Half (50%) of the trials reported who the trial information was targeted to. Most trials (75%) of school-aged participants targeted information towards children or children and their parents. Fourteen per cent of trials reported using incentives, half (50%) of which were in the form of compensation. Only 48% of trials reported sufficient data to determine if their recruitment targets were achieved. Of these, 70% achieved their targets.

Conclusions: Notable reporting shortcomings included: how families were recruited into the trial, who obtained consent and/or assent and how, who trial information was directed to, whether incentives were used and sufficient data to determine if the recruitment target was achieved. Forthcoming paediatric-specific reporting standards may improve reporting in this priority area. Our data provide a baseline for ongoing monitoring of the state of the research.

Useful pharmacodynamic endpoints in children: selection, measurement, and next steps Pediatric Research, 18 April 2018

Pharmacodynamic (PD) endpoints are essential for establishing the benefit-to-risk ratio for therapeutic interventions in children and neonates. This article discusses the selection of an appropriate measure of response, the PD endpoint, which is a critical methodological step in designing pediatric efficacy and safety studies. We provide an overview of existing guidance on the choice of PD endpoints in pediatric clinical research. We identified several considerations relevant to the selection and measurement of PD endpoints in pediatric clinical trials, including the use of biomarkers, modeling, compliance, scoring systems, and validated measurement tools. To be useful, PD endpoints in children need to be clinically relevant, responsive to both treatment and/or disease progression, reproducible, and reliable. In most pediatric disease areas, this requires significant validation efforts. We propose a minimal set of criteria for useful PD endpoint selection and measurement. We conclude that, given the current heterogeneity of pediatric PD endpoint definitions and measurements, both across and within defined disease areas, there is an acute need for internationally agreed, validated, and condition-specific pediatric PD endpoints that consider the needs of all stakeholders, including healthcare providers, policy makers, patients, and families.

Reporting of interventions and “standard of care” control arms in pediatric clinical trials: a quantitative analysis Pediatric Research, 13 June 2018

Background: In pediatric medicine, the usual treatment received by children (“standard of care”) varies across centers. Evaluations of new treatments often compare to the existing “standard of care” to determine if a treatment is more effective, has a better safety profile, or costs less. The objective of our study was to evaluate intervention and “standard of care” control arms reported in published pediatric clinical trials.

Methods: Pediatric clinical trials, published in 2014, reporting the use of a “standard of care” control arm were included. Duplicate assessment of reporting completeness was done using the 12-item TIDieR (Template for Intervention Description and Replication) checklist for both the “standard of care” control arms and intervention arms within the same published study.

Results: Following screening, 214 pediatric trials in diverse therapeutic areas were included. Several different terms were used to describe “standard of care.” There was a significant difference between the mean reported TIDieR checklist items of “standard of care” control arms (5.81 (SD 2.13) and intervention arms (8.45 (SD 1.39, p < 0.0001).

Conclusions: Reporting of intervention and “standard of care” control arms in pediatric clinical trials should be improved as current “standard of care” reporting deficiencies limit reproducibility of research and may ultimately contribute to research waste

2017

Response biomarkers in neonatal intervention studies Pediatric Research, 27 September 2017

Background: Up to 90% of all drugs used in neonatal intensive care units (NICUs) have not been clinically tested for safety and efficacy. To promote drug development for neonates, the pharmaceutical industry is moving toward rigorous testing, necessitating the need to development, and validating biomarkers in neonates to predict their response. The objective of this review is to evaluate the quality of the response biomarker reporting in neonatal clinical trials.

Methods: A validated literature search strategy was applied. Prospective neonatal intervention studies reporting response biomarkers published in 2014 were included. The data were extracted independently and in duplicate using a data-extraction form.

Results: Following the full-text review, 167 published prospective neonatal trials were included; 35% (59/167) reported the use of response biomarkers. In these 59 trials, we identified 275 biomarkers used to measure the response (pharmacodynamics and safety) reported as primary or secondary outcomes. Heart rate and oxygen saturation were the most commonly reported. Measurement and instrumentation data were often not provided.

Conclusion: We identified a huge variability in the selection, measurement, and reporting of neonatal response biomarkers in prospective intervention studies. Reporting initiatives are needed to reduce research waste and improve the reproducibility of biomarker use in neonatal intervention studies.

2016

Important issues in the justification of a control treatment in paediatric drug trials Arch Dis Child, October 2016

Objective: The value of comparative effectiveness trials in informing clinical and policy decisions depends heavily on the choice of control arm (comparator). Our objective is to identify challenges in comparator reasoning and to determine justification criteria for selecting a control arm in paediatric clinical trials.

Design: A literature search was completed to identify existing sources of guidance on comparator selection. Subsequently, we reviewed a randomly selected sample of comparators selected for paediatric investigation plans (PIPs) adopted by the Paediatric Committee of the European Medicines Agency in 2013. We gathered descriptive information and evaluated their review process to identify challenges and compromises between regulators and sponsors with regard to the selection of the comparator. A tool to help investigators justify the selection of active controls and placebo arms was developed using the existing literature and empirical data.

Results: Justifying comparator selection was a challenge in 28% of PIPs. The following challenging paediatric issues in the decision-making process were identified: use of off-label medications as comparators, ethical and safe use of placebo, duration of placebo use, an undefined optimal dosing strategy, lack of age-appropriate safety and efficacy data, and drug dosing not supported by extrapolation of safety/efficacy evidence from other populations.

Conclusions: In order to generate trials that will inform clinical decision-making and support marketing authorisations, researchers must systemically and transparently justify their selection of the comparator arm for their study. This report highlights key areas for justification in the choice of comparator in paediatric clinical trials.