The Food and Drug Administration (FDA) has approved the supplemental Biologics License Application (sBLA) for Palynziq® (pegvaliase-pqpz; BioMarin) to increase the maximum allowable dose to 60mg for the treatment of adults with phenylketonuria (PKU) who have uncontrolled blood phenylalanine (Phe) concentrations (greater than 600μmol/L) on current management. Previously, the maximum dose was 40mg.

The approval was based on data from a phase 3 open-label extension study that evaluated the long-term efficacy and safety of Palynziq in 86 adults with PKU. Patients received subcutaneous injections of Palynziq at doses greater than 40mg up to 60mg once daily. The co-primary end points were the change in blood Phe concentration and the incidence of treatment-emergent adverse events.

Findings showed that 66% of patients treated with Palynziq for at least 2 years had a blood Phe level equal to or less than 360μmol/L, and 50% of patients had blood Phe levels equal to or less than 120μmol/L at 2 years. Moreover, among the 77 patients who were treated for at least 36 months, blood Phe concentrations equal to or less than 600, 360, and 120μmol/L were observed in 75% (n=58), 66% (n=51), and 48% (n=37) of patients, respectively, at 3 years. The safety profile of Palynziq was consistent with its known profile, irrespective of dose.

“Adding a maximum dose of 60mg allows more patients to optimize and achieve treatment goals to keep blood Phe levels within the range set in the medical guidelines or within normal range,”  said Cary Harding, MD, professor at Oregon Health & Science University and Steering Committee Chair for the Palynziq program. “More than 6 years of long-term safety data further supports a well-characterized safety profile similar to the initial data and is important information to physicians considering a chronic therapy.”

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BioMarin recently received Fast Track designation from the FDA for its investigational gene therapy BMN 307 for the treatment of patients with PKU. BMN 307 is an adeno-associated virus type 5-phenylalanine hydroxylase gene therapy designed to normalize blood Phe concentration levels in patients with PKU by inserting a correct copy of the PAH gene into liver cells.

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BioMarin, pioneer in rare disease treatments for phenylketonuria (PKU), receives FDA approval of label expansion to allow maximum dose of 60 mg for Palynziq® (pegvaliase-pqpz) injection for treatment of adults with PKU. [press release]. San Rafael, CA: BioMarin; October 7, 2020.