First Patient Dosed in Trial for Phenylketonuria Gene Therapy

BioMarin has been working to develop treatments for phenylketonuria for 15 years, and it is a cause they are very committed to. That is why they are so excited to begin dosing in their PHEARLESS study, which will evaluate the dosage and safety of the gene therapy BMN 307.

About Phenylketonuria (PKU)

One of every 10,000 to 15,000 births are affected by phenylketonuria, a condition that is characterized by an accumulation of the amino acid phenylalanine. This buildup can cause serious health problems and and trigger major symptoms, which begin to appear a few months after birth. When they do appear, effects include seizures, developmental delay, heart defects, fair eyes and skin, hyperactivity, intellectual delays, microcephaly, decreased bone strength, skin rashes, and an unusual odor.

A mutation in the gene that produces the enzyme phenylalanine hydroxylase is responsible for PKU. This enzyme is needed to break down the amino acid phenylalanine. Both parents need to pass down the mutated gene in order for a child to be affected. Early detection is necessary to effectively treat this condition. Once developmental delays occur, they cannot be reversed. The major treatment is dietary changes to avoid ingesting the amino acid phenylalanine. This means avoiding foods that are high in protein. Doctors will closely monitor the levels of phenylalanine, and they may administer Kuvan to reduce levels.

BMN 307 for PKU

BMN 307 is an AAV5-phenylalanine hydroxylase gene therapy that is intended to regulate levels of phenylalanine in the blood. It does so by placing a non-mutated PAH gene in the liver cells. BioMarin is currently testing it to ensure that it is safe and see if one dose can regulate plasma Phe levels, fix the natural Phe metabolism, and allow PKU patients to eat a normal diet.

The study, in which the first participant was just dosed, is one of two that BioMarin is conducting to evaluate BMN 307. PHEARLESS will study the safety, tolerability, and efficacy of one dose of the gene therapy, while the PHENOM study is observational and will measure clinical outcomes and new markers.

As BioMarin has been committed to PKU research for many years, they are very hopeful that this study ends in positive results, and that BMN 307 can better the lives of those with PKU.

Read more about this treatment here.

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