BioMarin Pharmaceutical Inc (Nasdaq: BMRN), a US-based biotechnology company, announced on Saturday new data regarding the efficacy and safety of PALYNZIQ (pegvaliase-pqpz) for the treatment of adolescents with phenylketonuria (PKU), which were presented at the 15th International Congress of Inborn Errors of Metabolism (ICIEM) in Kyoto, Japan, 2-6 September 2025.

According to the company, the Phase 3 PEGASUS study evaluating the efficacy and safety of PALYNZIQ in adolescents aged 12-17 demonstrated statistically significant blood phenylalanine (Phe) lowering compared to diet alone. The study enrolled 55 adolescents, randomised to receive PALYNZIQ (n=36) or diet alone (n=19). At baseline, the mean age was 14.3 years, mean blood Phe was 1026.4 µmol/L, and nearly half (49.1%) of participants had blood Phe levels above 1000 µmol/L. Notably, after the 72-week primary treatment phase, almost half of participants in the PALYNZIQ arm (n=14; 45.2%) achieved reductions in blood Phe concentrations of 50% or more from baseline, with many reaching guideline-recommended and even normal Phe target levels.

Ongoing extension phase of the PEGASUS trial will continue to evaluate long-term results of PALYNZIQ treatment for adolescents.

The company says that PALYNZIQ is the first and only enzyme substitution therapy approved to treat adults with PKU. It adds that it is on track with its planned submission of the PEGASUS study data to global health authorities to expand the approved indication for PALYNZIQ to include the treatment of adolescents.

PKU, or phenylalanine hydroxylase (PAH) deficiency, is a genetic condition affecting approximately 70,000 people in the regions of the world where BioMarin operates.