Including Adolescents in Adult Drug Trials
Quick Facts
Why Are New Medicines Often Studied in Children Later?
Drug development has traditionally moved from adult trials to pediatric studies, leaving children waiting longer for evidence-based dosing and age-appropriate formulations. The International Council for Harmonisation's E11(R1) guideline recognizes that pediatric research must account for growth, organ maturation, developmental stage, disease differences, and the practical difficulties of conducting trials in small patient populations.
Delayed research does not necessarily prevent clinicians from using a medicine in children. Instead, it can result in off-label treatment supported by incomplete pharmacokinetic, safety, or formulation data. Regulatory initiatives that bring pediatric planning into earlier development may help sponsors identify when dedicated studies are essential and when reliable adult evidence can inform a more focused pediatric program.
Can Adolescents Safely Join Clinical Trials Designed for Adults?
Including adolescents is most defensible when the condition occurs in both adolescents and adults, its biology is comparable across the groups, and the investigational drug has a well-understood mechanism. The protocol must still specify pediatric safeguards, appropriate consent and assent procedures, dose selection, safety monitoring, and criteria for stopping treatment.
This approach has received particular attention in oncology, where excluding adolescents from adult trials can delay access to targeted therapies for uncommon cancers. US Food and Drug Administration guidance published in 2019 explains circumstances in which adolescent patients may be considered for enrollment in adult oncology trials. That guidance does not support automatic inclusion: eligibility must be justified for the particular disease and medicine.
What Would Earlier Pediatric Planning Change for Patients?
According to Regulatory Affairs Professionals Society reporting, Japan's PMDA is outlining initiatives to encourage pediatric drug development. The practical value will depend on whether earlier regulatory discussions lead to executable development plans, multinational enrollment, suitable trial sites, and formulations that children can swallow or receive accurately.
Adult data can sometimes support pediatric development through extrapolation and pharmacometric modeling, but these tools do not eliminate the need for evidence. Researchers may still need to characterize drug exposure, adverse effects, developmental risks, treatment acceptability, and long-term outcomes. Infants and younger children generally require more distinct evaluation than adolescents because maturation can substantially alter drug absorption, metabolism, and clearance.
Frequently Asked Questions
No. Dosing must be justified using factors such as body size, organ maturation, pharmacokinetic evidence, prior safety findings, and modeling. Some adolescents may receive an adult dose, but this cannot be assumed solely from age.
Sometimes adult efficacy evidence can be partly extrapolated when disease progression and treatment response are sufficiently similar. Pediatric pharmacokinetic, dosing, formulation, and safety evidence may still be required.
Trials require ethics review, permission from a parent or legal guardian where applicable, the young person's assent when capable, age-appropriate information, careful risk monitoring, and additional safeguards for participants who cannot legally provide independent consent.
References
- Regulatory Affairs Professionals Society. Asia-Pacific Roundup: PMDA outlines initiatives to promote pediatric drug development in Japan. July 2026.
- International Council for Harmonisation. E11(R1): Addendum to Clinical Investigation of Medicinal Products in the Pediatric Population. 2017.
- US Food and Drug Administration. Considerations for the Inclusion of Adolescent Patients in Adult Oncology Clinical Trials: Guidance for Industry. March 2019.