On October 2, 2020, biotechnology company BioMarin Pharmaceutical (“BioMarin”) announced that its investigational gene therapy candidate BMN 307 received the Fast Track designation from the FDA. The therapy is designed to treat patients with phenylketonuria (PKU), a rare genetic disorder causing excess phenylalanine accumulation.
For over 15 years, BioMarin has contributed to research and drug development designed for patients with PKU. Currently, BioMarin has two FDA-approved PKU therapies and has conducted 41 clinical trials related to this condition. BMN 307 is an investigational gene therapy delivered using adeno-associated virus (AAV) vectors. According to MedlinePlus, an endeavor from the U.S. National Library of Medicine, gene therapy:
is an experimental technique that uses genes to treat or prevent disease. Researchers are testing several approaches to gene therapy, including replacing a mutated gene with a healthy copy of the gene; inactivating, or ‘knocking out,’ a mutated gene that is functioning improperly, [or] introducing a new gene into the body to help fight a disease.
In this case, BMN 307 delivers a functional PAH gene to help normalize and regulate phenylalanine levels. Currently, BioMarin is conducting the Phase 1/2 Phearless clinical trial to test the safety, efficacy, and tolerability of BMN 307. In fact, they recently dosed the first trial participant.
BMN 307 received Fast Track designation from the FDA. The FDA describes Fast Track designation as:
a process designed to facilitate the development, and expedite the review of [drugs and other biologics] to treat serious conditions and fill an unmet medical need.
Drug developers get increased communication with the FDA and may later apply for Priority Review. In addition to Fast Track designation, BMN 307 received the Orphan Drug designation. This latter status is designed for therapies treating patients with rare diseases, described as those affecting under 200,000 people.
Also known as phenylalanine hydroxylase (PAH) deficiency, phenylketonuria (PKU) is a rare genetic disorder causing excess phenylalanine accumulation. Phenylalanine is an essential amino acid. Commonly, it is found in artificial sweeteners, milk, eggs, and meat. While phenylalanine helps your body to create proteins, it can be harmful in excess amounts. Currently, researchers believe 1 in 10,000-15,000 births has PKU.
Symptoms usually occur within months of birth. Early detection and treatment help to address any health problems that might occur. Newborn screening panels assist with early detection. Later in life, PKU can be managed with specific diets that exclude phenylalanine. Symptoms include:
- Intellectual and developmental delays
- Behavioral difficulties
- Depression and anxiety
- Musty-smelling skin, urine, and breath
- Light skin and eyes
- Frequent skin rashes
- Heart defects
- Poor bone strength
Learn more about PKU.