Pharmacokinetics and Pharmacodynamics, Efficacy and Safety of Fremanezumab in Children and Adolescents with Migraine

Migraine affects up to 11% of children and adolescents, leading to substantial disability through school absenteeism, cognitive impairment, and reduced quality of life. Traditionally, preventive treatment options for this population have been limited to the off-label use of nutraceuticals, antiseizure medications, calcium channel blockers, serotonin modulators, antidepressants, or beta-blockers, with limited efficacy and tolerability data. Monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway have transformed adult migraine prevention, and fremanezumab is the first in this class to receive regulatory approval for pediatric use. In August 2025, the US Food and Drug Administration approved fremanezumab for the preventive treatment of episodic migraine in patients aged 6-17 years weighing at least 45 kg, based on the pivotal phase three SPACE trial. This randomized, placebo-controlled study demonstrated significant reductions in monthly migraine and headache days, with nearly half of treated participants achieving a ≥50% response rate, and a safety profile consistent with adult data. In this review, we provide an integrated, pediatric-focused synthesis of the pharmacokinetic, pharmacodynamic, and regulatory evidence supporting fremanezumab use in children and adolescents. In particular, we contextualize population pharmacokinetic modeling and pediatric phase 1 data to explain the rationale for weight-based dosing, exposure matching with adults, and the selection of the dosing regimens used in clinical trials and regulatory labeling. Pharmacokinetic analyses indicate that fremanezumab follows a two-compartment model with first-order absorption and a terminal half-life of approximately 30 days in pediatric patients, similar to adults, with body weight as the primary determinant of exposure. Finally, we discuss unresolved issues related to long-term CGRP blockade during growth, including theoretical effects on vascular regulation, bone metabolism, and neurodevelopment. Overall, fremanezumab represents a novel, mechanism-based preventive option for older children and adolescents with episodic migraine, while highlighting the need for continued longitudinal studies to define its long-term safety and optimal role in pediatric migraine management.