BioMarin Pharmaceutical Inc. (Nasdaq:BMRN) announced on 5/24/18 that BioMarin received standard approval from the U.S. Food and Drug Administration (FDA) for Palynziq (pegvaliase-pqpz) Injection to reduce blood phenylalanine (Phe) concentrations in adult patients with phenylketonuria (PKU), who have uncontrolled blood Phe concentrations greater than 600 micromol/L on existing management. Palynziq, a PEGylated recombinant phenylalanine ammonia lyase enzyme, is the first approved enzyme substitution therapy to target the underlying cause of PKU by helping the body to break down Phe. Palynziq is BioMarin's second approved treatment for this important condition.
PKU is a rare genetic disease that manifests at birth and results in a variety of cumulative toxic effects on the brain. PKU affects approximately 1 in 12,500 live births in the United States each year. PKU is marked by an inability to break down Phe, an amino acid that is found in all forms of protein. Left untreated, high levels of Phe become toxic to the brain and may lead to serious neurological and neuropsychiatric-related issues, impacting the way a person thinks, feels, and acts. Due to the seriousness of these symptoms, infants are screened at birth to ensure that they are diagnosed early and treated to avoid intellectual disability and other complications. Patients living with PKU require life-long management, including adherence to a challenging and severely restrictive daily diet of medical foods and formula that avoids the ingestion of Phe that is present in most foods.
The approval of Palynziq in the United States marks an important milestone for adults living with PKU who will now have access to an effective new treatment option for controlling their blood 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. 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," said Cary Harding, M.D., professor at Oregon Health & Science University and investigator for the Phase 3 studies.
Palynziq is expected to be available in the United States by the end of June, and BioMarin will begin the promotion of Palynziq immediately. Palynziq is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the Palynziq REMS.
Palynziq substitutes the deficient phenylalanine hydroxylase (PAH) enzyme in PKU with the PEGylated version of the enzyme phenylalanine ammonia lyase to break down Phe. Palynziq is administered using a dosing regimen designed to facilitate tolerability; Palynziq's safety profile consists primarily of immune-mediated responses, including anaphylaxis, for which robust risk management measures effective in clinical trials are in place.
Hypersensitivity is a potential problem associated with pegvaliase, seen in approximately 39% of patients compared to 14 percent with placebo. An immune reaction has also been seen.
One in every 14,000 babies born in the US are diagnosed with PKU and there are approximately 50,000 diagnosed patients in the areas where BioMarin has operations. The available treatment options are a strict diet and another BioMarin drug, sapropterin (Kuvan), a pill that only works in about half of patients. That drug generated $239.3 million in revenue for BioMarin in 2015.
As of this writing, BioMarin shares are up over 3% in pre-market trading.
