Pegvaliase: a novel treatment option for adults with phenylketonuria

In May 2018, the US Food and Drug Administration approved pegvaliase-pqpz (Palynziq*), the first enzyme substitution therapy for the treatment of phenylketonuria (PKU). This article provides an overview of the mechanism of action, pharmacokinetic properties, clinical efficacy, and the safety and tolerability profile of pegvaliase.

Relevant information was identified through a comprehensive literature search of several databases using the keywords pegvaliase, rAvPAL-PEG, and phenylketonuria. Additional information was gathered from the pegvaliase package insert, posters presented at scientific meetings, and materials provided from the manufacturer, BioMarin.

Pegvaliase is effective in decreasing blood phenylalanine levels, and is associated with a manageable side-effect profile. Phase III clinical trial data demonstrated that 60.7% of patients were able to achieve blood phenylalanine levels less than the guideline recommended 360 µmol/L at 24 months. Brief sub-studies also showed the improvement in inattention symptoms in patients treated with pegvaliase, compared to placebo.

Pegvaliase is a promising new treatment option for adults living with PKU. Further studies are warranted to determine long-term safety and clinical efficacy in sub-populations.