Dupixent Clears FDA for CSU in Children as Young as Two

Sanofi and Regeneron have secured FDA approval of dupilumab (Dupixent) for chronic spontaneous urticaria (CSU) in children aged two to 11 years who remain symptomatic despite H1 antihistamine treatment -- an expansion that establishes a regulatory precedent worth examining closely. The agency accepted an approval package built primarily on efficacy extrapolation from adult and adolescent phase 3 data, bridged to the pediatric population through pharmacokinetic data alone, a methodology that regulatory affairs teams across the industry will be watching as a potential template for future pediatric biologic submissions.

The approval rests on data from the LIBERTY-CUPID clinical study program. Efficacy was extrapolated from two phase 3 studies -- Study A and Study C (NCT04180488) -- conducted in adults and adolescents aged 12 years and older with CSU. In both studies, Dupixent significantly reduced itch severity and urticaria activity, measured as a composite of itch and hives, compared to placebo at Week 24. Adults and adolescents on Dupixent also demonstrated an increased likelihood of well-controlled disease or complete response versus placebo at Week 24. The pediatric-specific CUPIDKids study (NCT05526521), a single-arm phase 3 trial in children aged two to 11 years, contributed pharmacokinetic bridging data rather than independent efficacy endpoints. Pediatric safety was further supported by data drawn from Dupixent's existing approvals in other indications in this age group.

For QA and pharmacovigilance functions, the safety dataset warrants attention. Across Study A, Study B (NCT04180488), and Study C, the only adverse reaction occurring at a frequency of 2% or greater and more commonly than placebo was injection site reactions. No new adverse reactions were identified in the two-to-11 age cohort with CSU. The safety results across all four CSU studies were described as generally consistent with Dupixent's established profile in approved dermatological indications. Study B, which enrolled patients aged 12 and older who were inadequate responders or intolerant to anti-IgE therapy, provided additional safety data for the broader CSU population.

The mechanistic rationale centers on IL-4 and IL-13 signaling inhibition, which Sanofi positions as targeting central drivers of the type 2 inflammation implicated in CSU pathophysiology. CSU is now the fifth type-2-inflammation-driven disease for which Dupixent carries an approval in children younger than 12 years of age, and the ninth allergy-related indication in the molecule's overall label. For formulary and access teams at health systems, the approval extends a biologic option to a pediatric CSU population that previously had no approved biologic therapy and was limited to antihistamine-based management.

The regulatory pathway employed here -- efficacy extrapolation from a well-characterized adult and adolescent dataset combined with PK bridging in the target pediatric population -- reflects an approach aligned with FDA's existing pediatric extrapolation framework. As the industry continues to navigate the operational and ethical complexities of enrolling young children in interventional trials, this approval adds a documented, agency-accepted example to the extrapolation case library. Regulatory affairs leads preparing pediatric investigation plans or supplemental biologics license applications in type 2 inflammatory conditions should review the LIBERTY-CUPID submission structure as a reference point for study design and data package construction.