What Is Sephience, and Why Does It Matter?
Sephience (sepiapterin) is a new oral medication approved by the FDA to treat a rare inherited condition known as phenylketonuria (PKU) in adults and children aged 1 month or older. PKU affects about 58,000 people worldwide. Early diagnosis and treatment are important to prevent long-term damage.
PKU affects how the body breaks down phenylalanine (Phe), an amino acid found in protein-rich foods. People with PKU lack or have a faulty version of an enzyme called phenylalanine hydroxylase (PAH), which is needed to break down Phe. Without treatment, Phe can build up in the blood and lead to serious complications, especially in infants and children, such as brain damage, learning disabilities, memory loss, seizures, and behavioral issues.
Sephience works by increasing levels of tetrahydrobiopterin (BH4), a natural substance that helps PAH function properly. This helps the body better process Phe.
Why Was It Approved?
Sephience was approved because studies showed it is a safe and effective oral treatment that can lower blood Phe levels and provide lasting relief in children and adults with sepiapterin-responsive PKU.
In one study involving 98 patients with sepiapterin-responsive PKU, 49 received Sephience and had an average 63% drop in blood Phe levels after six weeks, while others on placebo had little to no change.
In an extension study that tested dietary Phe tolerance in 100 patients treated with sepiapterin, patients were able to eat over twice as much Phe-containing foods after about six months while keeping their blood levels within a safe range.
The most common side effects reported during the study were mild to moderate and included diarrhea, headache, stomach pain, changes in stool color, and throat pain. Some children developed low Phe levels, which can also be harmful and needs close monitoring.
What Do I Need to Know?
Sephience is taken by mouth once daily with food, with the dose depending on the patient’s age and weight. It comes as a powder that should be mixed with water, juice, or soft food to make it easier to swallow. Once mixed, it should be taken right away, or it can be stored up to six hours at room temperature or for up to 24 hours in the refrigerator.
Patients must stay on a Phe-restricted diet while taking Sephience. Regular blood tests are needed to check Phe levels, and your health care provider will adjust the dose of the medicine or your diet as needed. This is especially important for children, who are more sensitive to changes in Phe levels.
Sephience may increase the risk of bleeding, and some patients have had issues like bruising, prolonged bleeding, or heavy periods while taking it. Sephience may also interact with certain medicines, especially those used for treating infections or cancer. Some drugs can also lower blood pressure when taken with Sephience. Be sure to tell your health care provider about all the medicines and supplements you or your child are taking.
Health care providers who are experienced in treating PKU should oversee treatment. A trial period is often needed to see if a patient responds to Sephience.