New Strategies for the Conduct of Clinical Trials in Pediatric Pulmonary Arterial Hypertension: Outcome of a Multistakeholder Meeting With Patients, Academia, Industry, and Regulators, Held at the European Medicines Agency on Monday, June 12, 2017

Aims: Drug development for paediatric pulmonary arterial hypertension (PAH) ispressingly needed. Experts from the US Food and Drug Administration, EuropeanMedicines Agency, Health Canada, key opinion leaders, academia, patients, and industry representatives held a workshop on 12th June 2017 dedicated to addressing challenges and unmet needs. This report summarises the approaches proposed during the meeting to address key issues in extrapolation, trial design, and study endpoints in pediatric drug development.Methods and Results: A pre-workshop stakeholder survey was conducted and showed that most respondents believe the pathophysiology of heritable PAH and some forms of idiopathic PAH is thought to be sufficiently similar in adult and paediatric patients, although the clinical manifestations may differ. In this situation, placebo-controlled trials might not be required to confirm clinical benefit in paediatrics. The study endpoints used to support drug approvals in adults were reviewed to determine if these existing study endpoints can be applied in paediatric PAH efficacy trials. It showed that non-invasive study endpoints, such as the time to clinical worsening, WHO functionalclass, and 6-Minute-Walk-Test could be applicable in paediatric PAH trials, although each presents some limitations in paediatrics.Conclusion: Extrapolation of efficacy from informative adult studies may be appropriate in some forms of PAH. Initial dose-finding studies and exposure-response modelling are warranted in paediatric PAH, followed by an efficacy and safety study to explore the response to treatment and exposure-response relationship. A novel, non-invasive, developmentally-appropriate, and reliable study endpoint needs to be developed.