FDA Approves PTC’s PKU Therapy

Rare Daily Staff

The U.S. Food and Drug Administration has approved PTC Therapeutics’ Sephience for the treatment of children and adults living with the rare metabolic disorder phenylketonuria.

Phenylketonuria (PKU) is caused by a defect in the gene that encodes the enzyme required to break down phenylalanine (Phe). If left untreated or poorly managed, Phe—an essential amino acid found in all proteins and most foods—can build up to harmful levels in the body. This can cause severe and irreversible disabilities, such as permanent intellectual disability, seizures, delayed development, memory loss, and behavioral and emotional problems. Newborns with PKU initially do not have any symptoms, but symptoms are usually progressive, and damage caused by toxic levels of Phe in the first few years of life is irreversible.

Sephience is indicated for the treatment of hyperphenylalaninemia (HPA) in adult and pediatric patients with PKU. Sephience is a natural precursor of the enzymatic co-factor BH4, a critical co-factor for phenylalanine hydroxylase (PAH). Sephience effectively reduces blood Phe levels and has the potential to treat a broad range of PKU patients. Sephience is approved in the European Economic Area and the United States.

The FDA approval is based on 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.

“We are excited to have reached this important milestone for those affected by PKU,” said Matthew Klein, CEO of PTC Therapeutics. “The broad labeling reflects the potential of Sephience to meet the significant unmet need of PKU patients. The Sephience clinical data, along with our expertise in launching rare disease therapies, positions Sephience to become the future standard of care. Our experienced customer-facing teams are ready to bring this therapy to children and adults with PKU in the United States as quickly as possible.”

Photo: Matthew Klein, CEO of PTC Therapeutics