Pegvaliase Gets Priority Review for PKU Treatment in Adolescents

The Food and Drug Administration (FDA) has accepted for Priority Review the supplemental Biologics License Application (sBLA) for pegvaliase-pqpz to include treatment of adolescents aged 12 to 17 years with phenylketonuria (PKU).

Pegvaliase, a phenylalanine (Phe)-metabolizing enzyme, is currently marketed under the brand name Palynziq^® to reduce blood Phe concentrations in adult patients with PKU who have uncontrolled blood Phe concentrations greater than 600µmol/L on existing management.  

The sBLA includes data from the phase 3 PEGASUS trial (ClinicalTrials.gov Identifier: NCT05270837), which evaluated the safety and efficacy of pegvaliase in adolescents aged 12 to 17 years with PKU. Study participants (N=55; mean age: 14.3 years; baseline mean blood Phe: 1026.4µmol/L) were randomly assigned 2:1 to receive pegvaliase (n=36) or diet alone (comparator arm; n=19). 

Findings showed pegvaliase reduced mean blood Phe levels from baseline (primary endpoint) by 49.7% compared with 0.3% with diet only at week 72. Participants treated with pegvaliase achieved the following blood Phe levels compared with diet only:

• Less than or equal to 600µmol/L: 51.6% vs 5.9%;
• Less than or equal to 360µmol/L: 38.7% vs 0%;
• Less than or equal to 120µmol/L: 19.4% vs 0%. 

The safety profile of pegvaliase in adolescents was consistent with the known profile in adults. The majority of adverse events were manageable, with 5.6% of serious adverse events (anaphylaxis) leading to study discontinuation. 

“Adolescents and young adults with PKU need better options that can deliver meaningful reductions in blood Phe levels and provide greater dietary freedom,” said Greg Friberg, MD, Executive Vice President and Chief Research & Development Officer at BioMarin. “The results we observed in the PEGASUS trial demonstrated the potential Palynziq can offer to help adolescents achieve guideline-recommended and even normal Phe levels, while eating significantly more protein from whole foods.”

A Prescription Drug User Fee Act target date of February 28, 2026 has been set for the application.

This article originally appeared on MPR