Positive results for treatment to reduce blood phenylalanine (Phe) concentrations in patients with phenylketonuria (PKU)

BioMarin Pharmaceutical Inc. announced that the Committee for Medicinal Products for Human Use (CHMP), the scientific committee of the European Medicines Agency (EMA), has adopted a positive opinion for the company's Marketing Authorization Application (MAA) for Palynziq (pegvaliase) Injection to reduce blood phenylalanine (Phe) concentrations in patients with phenylketonuria (PKU) aged 16 and older, who have inadequate blood Phe control (blood Phe levels greater than 600 micromol/L) despite prior management with available treatment options. In addition, the CHMP noted that the data collected in the Phase III trial and extension study was suggestive of an improvement in inattention and mood symptoms.

In May 2018, Palynziq, a PEGylated recombinant phenylalanine ammonia lyase enzyme, received regulatory approval from the FDA making it the first approved enzyme substitution therapy to target the underlying cause of PKU by helping the body break down Phe.

The CHMP based its opinion on the totality of data from the Palynziq clinical development program including a Phase III pivotal study, PRISM-2, which showed that a group of patients taking either 20 mg or 40 mg of Palynziq maintained mean blood Phe levels at 553.0 µmol/L and 566.3 µmol/L respectively, compared to their baseline in the randomized discontinuation trial (RDT) of 596.8 µmol/L and 410.9 µmol/L. The corresponding 20 mg and 40 mg placebo treated groups mean blood Phe levels increased to 1509.0 µmol/L and 1164 µmol/L compared to their RDT baselines of 563.9 µmol/L and 508.2 µmol/L respectively.The 8-week PRISM-2 double-blind, placebo-controlled, randomized drug discontinuation trial (RDT) consisted of 86 patients, who were randomized to either remain on Palynziq or receive matching placebo.