BioMarin’s phase 3 study of pegvaliase meets primary endpoint

The drug, however, did not show enough benefit in related inattention and mood complications. Pegvaliase is being tested against a placebo in patients of Phenylketonuria (PKU) or phenylalanine hydroxylase (PAH) deficiency.

In the 8 week Prism-2 double-blind, placebo-controlled, randomized drug discontinuation trial (RDT), 86 patients were randomized to either remain on pegvaliase or receive matching placebo.

The study demonstrated the ability to enhance Phe levels in PKU patients who at baseline do not have to follow a Phe-restricted diet.

In the secondary endpoints of the 8 week RDT, the company did not see benefit in inattention or mood scores in patients treated with pegvaliase compared to placebo.

The company said in an exploratory sub study of cognitive function in nine patients, the Cambridge Neuropsychological Test Automated Battery demonstrated trends of improvement favoring pegvaliase.

BioMarin expects to submit a marketing application for the drug later this year, subject to further negotiations with the US Food and Drug Administration.

BioMarin chief medical officer Hank Fuchs said: "We are pleased that the double-blind, randomized, placebo-controlled part of the PRISM-2 trial demonstrated strong blood Phe reduction in pegvaliase treated patients whose dietary protein intake was unrestricted at baseline and maintained throughout the study.

"We are committed to the global PKU community and to bringing them a medicine that has the potential to treat PKU adult patients.

"We look forward to sharing this data with the regulatory authorities in the US and Europe to continue the process of bringing an important therapy to patients."

PAH deficiency is a genetic disorder affecting about 50,000 diagnosed patients in the developed world and is caused by a deficiency of the enzyme PAH.