BioMarin’s Palynziq Becomes First Approved Enzyme Therapy for PKU

BioMarin’s Palynziq has been approved by the FDA to lower blood phenylalanine (Phe) levels, adding to their treatment portfolio for the rare form of lysosomal storage disorder, phenylketonuria (PKU). Palynziq is the first enzyme therapy designed to break down excess Phe, thereby managing patients with PKU. The approval coincides with National PKU Awareness Month.

“BioMarin is thrilled to be able to offer this important new therapy to adults with PKU who are unable to control their Phe levels with existing options,” said Jean-Jacques Bienaimé, chairman and chief executive officer of BioMarin. “The approval of Palynziq is the culmination of more than a decade of perseverance by BioMarin employees dedicated to bringing treatments to PKU adult patients.”

According to BioMarin, approximately 1 in every 12,500 live births in the US will be affected by PKU. Patients with this genetic disorder lack the enzyme necessary to break down Phe, an amino acid that is found in protein.

“This is a novel enzyme substitution therapy that helps address a significant unmet need in PKU patients who have been unable to control their blood Phe levels with current treatment options,” said Dr. Julie Beitz, director of the Office of Drug Evaluation III in FDA’s Center for Drug Evaluation and Research. “This new approval demonstrates our commitment to approving advancements in treatment that will give patients living with PKU different options for care.”

All babies are screened for PKU at birth because unregulated Phe levels can have extremely damaging effects on the brain. Patients living with PKU must follow a strict diet to avoid eating excess Phe.

“The goal in treating PKU is to keep blood Phe levels within the range set in the medical guidelines, as elevation of Phe can be toxic and damaging to the brain,” said Dr. Cary Harding, professor at Oregon Health & Science University and investigator for the Phase 3 studies. “Palynziq provides another much-needed tool for us to help adult patients control their Phe levels, which previously had not been achievable for many adults living with the condition.”

This is BioMarin’s second FDA approval for an indication in treating PLU. Kuvan is the only other drug approved to lower blood Phe levels, however this product is only indicated for use in patients with a specific type of PKU.

“Palynziq has the potential to be a game-changing therapy for adults in the PKU community who have struggled throughout their lives to control their Phe levels, despite rigorous management,” said Christine Brown, MS, executive director of the National PKU Alliance. “BioMarin has provided unwavering support for the PKU community and continues innovative medical research to advance treatment options for this rare genetic disease.”

BioMarin plans to get Palynziq into the hands of patients as quickly as possible, with availability of the PKU medication likely in late June. The company is also awaiting a decision on their Marketing Authorization Application for Palynziq from the EMA.

However, as some patients involved in the clinical program for Palynziq experienced anaphylaxis, the FDA is mandating that BioMarin include a boxed warning on the product’s packaging to warn patients and physicians about this potential adverse event. Palynziq must also only be prescribed under the drug’s Risk Evaluation and Mitigation Strategy (REMS) which requires doctors to prescribe the PKU treatment along with an auto-injectable form of epinephrine such as the EpiPen.