Paediatric Medicines11 August 2026

Biosimilars and children: what extrapolation of indications means in practice

Biosimilars can win approval for paediatric uses without paediatric trials. The bigger practical issue is often whether the right dose and device exist for a small child.

By NextGenHealth Editorial Team2 min read

Glass medical vials and an intravenous fluid bottle on a dark surface — Photo: National Cancer Institute / Unsplash

In brief

How biosimilars gain paediatric indications through extrapolation, and the practical issues for children: low-dose presentations, devices and switching.

Biologic medicines such as anti-TNF antibodies have transformed the treatment of paediatric conditions including juvenile idiopathic arthritis and inflammatory bowel disease. As their patents expire, biosimilars are arriving, and children are among the patients being switched.

How biosimilars get paediatric indications

A biosimilar is approved by showing that it is highly similar to an existing reference biologic, with no clinically meaningful differences. That case rests mainly on detailed analytical comparison and usually on a clinical study in one sensitive population, typically adults.

Regulators can then extrapolate approval to the reference product’s other indications, including paediatric ones, if the scientific justification holds: the same mechanism of action, comparable pharmacokinetics and no reason to expect a different safety profile. Dedicated paediatric biosimilar trials are rarely required.

Where practice gets complicated

The scientific case for extrapolation is generally accepted. The practical problems are more mundane:

Presentations. A biosimilar may launch only in adult strengths. If the reference product offered a low-dose pre-filled syringe for small children, the biosimilar may not, at least at first.
Devices. Children and carers become used to a particular injection pen. A switch to a different device needs training and can affect adherence.
Excipients. Formulations can differ, which matters for children with sensitivities.

What clinicians and payers want

Paediatric specialists have generally supported biosimilar use, given the savings involved, while asking for clear communication with families and attention to presentations suitable for children. Payers increasingly expect manufacturers to cover the full range of strengths the reference product offered, rather than only the most profitable ones.

Biosimilars
Extrapolation
Biologics
Juvenile idiopathic arthritis

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