The U.S. FDA has approved PTC Therapeutics’ oral powder, branded Sephience, for the treatment of children and adults living with phenylketonuria (PKU), a rare metabolic disease that affects the brain.
The approval includes labeling for the treatment of the broader condition, hyperphenylalaninemia — where there are elevated levels of the amino acid phenylalanine in the blood — in adult and pediatric patients 1 month of age and older with sepiapterin-responsive PKU.
The FDA approval is based on the evidence of significant efficacy and safety from the phase 3 APHENITY trial as well as durability of treatment effect in the APHENITY long-term extension study.
The drug won marketing authorization from the European Commission last month, greenlighting it in all 27 EU member states as well as Iceland, Norway and Liechtenstein. The launch is already underway in Germany.
Sephience — an oral powder mixed with water or apple juice and administered once daily — is a natural precursor of the enzymatic co-factor BH4, a critical co-factor for phenylalanine hydroxylase. Through its mechanism of action, Sephience is able to effectively reduce blood phenylalanine levels. Phenylalanine is an essential amino acid found in all proteins and most foods, and if it builds up to harmful levels in the body can cause severe and irreversible disabilities such as permanent intellectual disability, seizures, delayed development, memory loss, and behavioral and emotional problems.