Pediatric antihypertensive trial failures: analysis of end points and dose range

Research Gaps in Primary Pediatric Hypertension

Hypertension affects >40% of the US population and is a major contributor to cardiovascular-related morbidity and mortality. Although less common among children and adolescents, hypertension affects 1% to 5% of all youth. The 2017 Clinical Practice Guideline for the Diagnosis and Management of High Blood Pressure in Children and Adolescents provided updates and strategies regarding the diagnosis and management of hypertension in youth. Despite this important information, many gaps in knowledge remain, such as the etiology, prevalence, and trends of hypertension; the utility and practicality of ambulatory blood pressure monitoring; practical goals for lifestyle modification that are generalizable; the long-term end-organ impacts of hypertension in youth; and the long-term safety and efficacy of antihypertensive therapy in youth. The Eunice Kennedy Shriver National Institute of Child Health and Human Development, in collaboration with the National Heart, Lung, and Blood Institute and the US Food and Drug Administration, sponsored a workshop of experts to discuss the current state of childhood primary hypertension. We highlight the results of that workshop and aim to (1) provide an overview of current practices related to the diagnosis, management, and treatment of primary pediatric hypertension; (2) identify related research gaps; and (3) propose ways to address existing research gaps.

Present state and future challenges in pediatric abdominal pain therapeutics research: Looking beyond the forest

At the present time, it is nearly impossible to treat pediatric functional gastrointestinal disorders associated with pain in an evidence based fashion. This is due to the overall lack of controlled studies and, even more importantly, the complexity of the contributors to disease phenotype which are not controlled or accounted for in most therapeutic trials. In this manuscript, we review the challenges of defining entry criteria, controlling for the large number of biopsychosocial factors which may effect outcomes, and understanding pharmacokinetic and pharmacodynamic factors when designing therapeutic trials for abdominal pain in children. We also review the current state of pediatric abdominal pain therapeutics and discuss trial design considerations as we move forward.

Paediatric drug development: the impact of evolving regulations

Children deserve medicines that are adapted to their needs. The need to include children in drug development has been recognised increasingly over the past few decades. Legal and regulatory frameworks are well established in the EU and US. The amount of work done to study medicines for children is significantly greater than it was 10 years go. Proof-of-concept has been demonstrated for all segments of the paediatric drug development pipeline. It is now time to examine how the practice of developing medicines for children has evolved within those frameworks and to determine how that work should be generalised. This review describes the development of medicines for children and critically appraises the work that has been done within those frameworks. Significant effort is needed to realize the potential provided by the current regulatory framework. Using the work programme of the Global Research in Paediatrics (GRiP) Network of Excellence as a template we outline current work and future growing points.

Screening for hypertension in children and adolescents to prevent cardiovascular disease

BACKGROUND AND OBJECTIVE

The prevalence of hypertension is increasing in children, and may persist into adulthood. This systematic review was conducted for the US Preventive Services Task Force recommendation on the effectiveness of screening asymptomatic children and adolescents for hypertension in order to prevent cardiovascular disease.

METHODS

Eligible studies were identified from Medline and the Cochrane Library (through July 2012). We included trials and controlled observational studies in asymptomatic children and adolescents on the effectiveness and harms of screening and treatment, as well as accuracy of blood pressure measurement. One author extracted study characteristics and results, which were checked for accuracy by a second author.

RESULTS

No studies evaluated the effects of screening for hypertension on health outcomes. Two studies of screening tests for elevated blood pressure reported moderate sensitivities (0.65, 0.72) and specificities (0.75, 0.92). Sensitivities and specificities of child hypertension for the later presence of adult hypertension (7 studies) were wide ranging (0-0.63 and 0.77-1.0, respectively), and associations between child hypertension and carotid intima media thickening and proteinuria in young adults (3 studies) were inconsistent. Seven studies reported that drug interventions effectively lowered blood pressure in adolescents over short follow-up periods. No serious treatment-related adverse effects were reported.

CONCLUSIONS

There is no direct evidence that screening for hypertension in children and adolescents reduces adverse cardiovascular outcomes in adults. Additional studies are needed to improve diagnosis and risk stratification of children with elevated blood pressure and to quantify risks and benefits of interventions.

Effect of placebo on ambulatory blood pressure monitoring in children

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) has been proposed as a useful tool for more accurately diagnosing hypertension (HTN) and evaluating blood pressure (BP) response in pediatric anti-hypertensive trials. ABPM captures multiple BP measurements during routine daily activities and is thus an excellent method for identifying white-coat HTN. Additionally, ABPM measurements in adults do not demonstrate the placebo effect commonly seen with casual BP measurements, although this has yet to be evaluated in children. Therefore,, the aim of this study was to assess the effect of placebo on ABPM measurements in children.

METHODS

A total of 141 children aged 5-16 years with elevated BP were randomized into a multi-center, single-blind, cross-over trial. Subjects received a placebo pill prior to wearing a 24-h ABPM device at one of two visits separated by 1-2 weeks. Study procedures were otherwise identical at both visits.

RESULTS

Mean systolic and diastolic BP for all measured time periods were similar between visits, as was the number of children diagnosed with HTN at each visit.

CONCLUSION

Having confirmed HTN at baseline did not affect the impact of placebo on mean BP. If confirmed, this lack of placebo effect on ABPM measurements may allow for the design of direct comparison pediatric anti-hypertensive trials without a placebo arm.

Is randomization to placebo safe? Risk in placebo-controlled angina trials: angina risk meta-analysis

OBJECTIVE

It was the aim of this study to document the risks of symptomatic patients with angina in placebo-controlled, anti-anginal drug development trials in which symptom-limited exercise testing was used as the primary endpoint.

PATIENTS AND METHODS

The original case report forms submitted to the United States Food and Drug Administration in support of approval of new or supplemental new drug applications between 1973 and 2001 were identified and subjected to a by-patient meta-analysis, utilizing both a maximum likelihood analysis and classical Mantel-Haenszel methods.

RESULTS

There were 63 placebo-controlled, clinical trials that randomized 10,865 patients, with 1,047 patient-years of observation time. The trials involved 21 different chemical entities from 4 different drug classes. The relative risk (RR) for withdrawal (placebo compared to drug-treated patients) was not increased [RR = 0.92, 95% confidence interval (CI) 0.78-1.08; p = 0.28]. Of interest, a RR of 0.54 (95% CI 0.26-1.04; p < 0.068) for irreversible harm (a combination of cerebrovascular accidents, myocardial infarction and death) and a RR of 0.89 (95% CI 0.61-1.30; p = 0.56) for serious cardiovascular events (myocardial infarction, congestive heart failure, cerebrovascular accidents) both non-statistically significantly favored being randomized to placebo.

CONCLUSIONS

For the development of current or future drugs for the treatment of angina, there is no obvious contraindication to the use of placebo controls and exercise tolerance testing.