Participating in clinical trials by age-groups

From the point of view of clinical trials, children under 18 are considered minors and a paediatric population that can be divided into several age groups providing a basis for paediatric study design.

One of the most important factors in age-groups is how the participants, children and adolescents, are able to be involved in the clinical trial decision-making process expressing their opinions and taking part to discussions together with their legal representatives (i.e. guardians / parents) and the treating physicians according to their age and developmental stage. It must be notified that the chronological age only partly correlates with maturity, and age can be only used as a practical instrument to get guidance for defining age groups.

The following age-groups according to the maturity and ability to be involved in the European Ethics Guideline (Ethical Considerations for Clinical Trials on Medicinal Products conducted with Minors; R1; 2017);

• Newborns and infants (from birth to 2 years of age)
• Pre-schoolers (2-5 years of age)
• Schoolers (6-9 years of age)
• Adolescents (10-18 years of age)

Another type of categorization can be used, if the clinical trial design is focused on more specific pharmacological or metabolic definitions (ICH E11: Clinical Investigation of Medicinal Products in the Pediatric Population; R1; 2017);

• Preterm newborn infants
• Term newborn infants (0 to 27 days)
• Infants and toddlers (28 days to 23 months)
• Children (2 to 11 years)
• Adolescents (12 to 16-18 years; dependent on region)

In practice, this judgment is more flexible and accurate age classification cannot be done due to considerable overlap (e.g., physical, cognitive, and psychosocial) in developmental issues across the various age categories. Notably, in long-term studies, paediatric patients may move from one age category to another.