BioMarin’s PALYNZIQ Wins FDA Approval for Adolescents After 473 µmol/L Phe Drop
FDA approves BioMarin’s sBLA for PALYNZIQ to treat 12–17-year-olds with PKU after Phase 3 PEGASUS showed mean blood phenylalanine reductions of 473 µmol/L versus 19 µmol/L at Week 72 (treatment difference 409 µmol/L; 95% CI –579 to –240). This expands the only enzyme substitution therapy to adolescents.
1. FDA Approval Expansion
The FDA has approved the supplemental Biologics License Application for PALYNZIQ to include patients aged 12 to 17 with phenylketonuria. This expands access to the only enzyme substitution therapy for adolescents struggling to maintain safe blood phenylalanine levels under existing dietary management.
2. Phase 3 PEGASUS Trial Results
In the Phase 3 PEGASUS study, 36 adolescents receiving PALYNZIQ achieved a mean blood phenylalanine reduction of 473 µmol/L from a baseline of 1,025 µmol/L at Week 72, compared with a 19 µmol/L reduction in the diet-only arm (treatment difference 409 µmol/L; 95% CI –579 to –240). Participants had uncontrolled Phe levels above 600 µmol/L at enrollment.
3. Safety and Tolerability Profile
The most common adverse reactions in adolescents were injection site reactions, arthralgia, headache, pyrexia, hypersensitivity, dizziness, nausea, vomiting, fatigue and extremity pain. Reaction frequency was highest during dose induction and titration, decreasing during the maintenance phase.
4. Commercial and Regulatory Outlook
BioMarin plans to seek European Medicines Agency approval for this indication, targeting a global PKU population of approximately 70,000 in its operating regions. Expanding PALYNZIQ to adolescents could drive significant incremental revenue by reducing reliance on restrictive medical diets in this age group.