Phenylketonuria – European Clinical Trials Information Network https://clinicaltrials.eu Bridging Patients with Clinical Trials Fri, 19 Jun 2026 04:03:08 +0000 en-US hourly 1 https://wordpress.org/?v=7.0 https://clinicaltrials.eu/wp-content/uploads/2024/12/cropped-EU_icon-32x32.png Phenylketonuria – European Clinical Trials Information Network https://clinicaltrials.eu 32 32 A Study of Repinatrabit Compared to Placebo for Treatment of Patients with Phenylketonuria https://clinicaltrials.eu/trial/a-study-of-repinatrabit-compared-to-placebo-for-treatment-of-patients-with-phenylketonuria/ Wed, 29 Apr 2026 15:07:47 +0000 https://clinicaltrials.eu/trial/a-study-of-repinatrabit-compared-to-placebo-for-treatment-of-patients-with-phenylketonuria/ This study involves people with Phenylketonuria, which is a condition where the body cannot properly break down a substance called phenylalanine that is found in protein-containing foods. When phenylalanine builds up in the blood, it can cause various health problems. The study will test a medication called JNT-517, which is given as a film-coated tablet that is taken by mouth. Some people in the study will receive JNT-517 while others will receive placebo. The purpose of this study is to see how well JNT-517 works compared to placebo in lowering the levels of phenylalanine in the blood of people with Phenylketonuria.

The study is divided into two periods and will last up to 52 weeks. During the first period, which lasts 6 weeks, participants will be randomly assigned to receive either JNT-517 at a dose of 150 milligrams twice daily, JNT-517 at a dose of 75 milligrams twice daily, or placebo. Neither the participants nor the study doctors will know which treatment each person is receiving during this period. Blood samples will be collected regularly to measure phenylalanine levels. In the second period, all participants will receive JNT-517 at one of the two doses. Throughout the study, participants will need to maintain a stable diet and keep track of what they eat using diet diaries. Some participants may be able to gradually increase the amount of protein in their diet if their phenylalanine levels remain low enough.

The study will measure several things to determine if the treatment is working. The main measurement will be the change in blood phenylalanine levels after 6 weeks of treatment. The study will also look at how many people achieve certain target phenylalanine levels, whether people can eat more protein while keeping their phenylalanine levels controlled, and whether there are improvements in attention and thinking abilities. Safety will be monitored throughout the study by tracking any side effects or unwanted reactions that occur. Participants will attend regular visits where blood tests will be done, questionnaires will be completed, and any changes in health will be recorded.

]]> Study of Long-Term Neurocognitive Outcomes in Children with Phenylketonuria Treated with Sepiapterin https://clinicaltrials.eu/trial/study-of-long-term-neurocognitive-outcomes-in-children-with-phenylketonuria-treated-with-sepiapterin/ Wed, 29 Apr 2026 15:06:09 +0000 https://clinicaltrials.eu/trial/study-of-long-term-neurocognitive-outcomes-in-children-with-phenylketonuria-treated-with-sepiapterin/ This study is evaluating sepiapterin as a treatment for children with phenylketonuria (PKU). Phenylketonuria is an inherited disorder that increases levels of a substance called phenylalanine in the blood. If left untreated, high phenylalanine levels can damage the brain and cause severe intellectual disability. The purpose of this research is to evaluate how well sepiapterin preserves brain function in children with PKU when treatment begins early in childhood.

The study will follow children under 10 years of age over a period of several years to measure changes in their thinking abilities and intelligence. Researchers will use age-appropriate intelligence tests to track how children’s cognitive abilities develop while receiving sepiapterin treatment. During the study, children will continue their prescribed diet that controls protein and phenylalanine intake.

The research will also track quality of life measures and blood phenylalanine levels over time. This long-term follow-up will help determine if sepiapterin can provide lasting protection for brain development in children with PKU.

]]> Study on the Long-Term Safety of PTC923 (Sepiapterin) for Patients with Phenylketonuria https://clinicaltrials.eu/trial/study-on-the-long-term-safety-of-ptc923-sepiapterin-for-patients-with-phenylketonuria/ Wed, 29 Apr 2026 14:57:19 +0000 https://clinicaltrials.eu/trial/study-on-the-long-term-safety-of-ptc923-sepiapterin-for-patients-with-phenylketonuria/ This clinical trial is focused on studying a condition called Phenylketonuria (PKU), which is a type of metabolic disorder. People with PKU have difficulty breaking down an amino acid called phenylalanine, which is found in many foods. The study is testing a treatment called PTC923, also known as Sepiapterin, which is taken as a powder by mouth. The purpose of the study is to evaluate the long-term safety of this treatment and to observe any changes in the participants’ diet, specifically their intake of phenylalanine and protein.

Participants in the study will take PTC923 for a period of up to 24 months. During this time, researchers will monitor the safety of the treatment by checking for any side effects and conducting regular health assessments, including laboratory tests and physical exams. The study will also look at how the treatment affects the participants’ quality of life and their ability to tolerate dietary phenylalanine. Some participants will be asked to complete questionnaires about their quality of life, depending on their age and language.

The study aims to provide valuable information about the safety and effectiveness of PTC923 in managing Phenylketonuria. By understanding how this treatment works over a longer period, researchers hope to improve the care and dietary management of individuals with PKU. The trial is open-label, meaning that both the participants and the researchers know which treatment is being administered. This approach helps in closely monitoring the effects of the treatment throughout the study.

]]> Study Comparing Sepiapterin and Sapropterin for Treating Phenylketonuria in Patients Aged 2 Years and Older https://clinicaltrials.eu/trial/study-comparing-sepiapterin-and-sapropterin-for-treating-phenylketonuria-in-patients-aged-2-years-and-older/ Wed, 29 Apr 2026 14:30:12 +0000 https://clinicaltrials.eu/trial/study-comparing-sepiapterin-and-sapropterin-for-treating-phenylketonuria-in-patients-aged-2-years-and-older/ This clinical trial is focused on studying a condition called Phenylketonuria (PKU), which is a rare genetic disorder that affects how the body processes a substance called phenylalanine, found in many foods. The study will compare two treatments: Sepiapterin and Sapropterin. Sepiapterin is a new treatment being tested, while Sapropterin is an existing medication used to help manage PKU. The purpose of the study is to see how effective Sepiapterin is compared to Sapropterin in reducing the levels of phenylalanine in the blood of people with PKU.

Participants in the study will be randomly assigned to receive either Sepiapterin or Sapropterin for a certain period, and then they will switch to the other treatment. This type of study is called a crossover study. The study will last for several weeks, during which participants will take the medication in the form of either soluble tablets or powder for oral use. The researchers will monitor the participants’ blood phenylalanine levels to see how well each treatment works. Some participants may also receive a placebo during the study.

The study aims to provide valuable information about the effectiveness of Sepiapterin compared to Sapropterin in managing PKU. By participating, individuals with PKU can contribute to research that may improve treatment options for this condition in the future. The study is open to both male and female participants who are at least two years old and have been diagnosed with PKU. Participants will need to continue their current diet and follow the study procedures as instructed by the research team.

]]> Study of pegvaliase injections compared to diet control in adolescents aged 12-17 with phenylketonuria (PKU) https://clinicaltrials.eu/trial/study-on-the-safety-and-effectiveness-of-pegvaliase-for-adolescents-aged-12-17-with-phenylketonuria-pku/ Wed, 29 Apr 2026 14:27:43 +0000 https://clinicaltrials.eu/trial/study-on-the-safety-and-effectiveness-of-pegvaliase-for-adolescents-aged-12-17-with-phenylketonuria-pku/ This study focuses on adolescents with Phenylketonuria (PKU), a genetic condition where the body cannot properly break down an amino acid found in protein-rich foods. The study will test a medication called Palynziq (pegvaliase), which is given as an injection under the skin. The purpose is to evaluate if this treatment is safe and effective for young patients aged 12-17 years who have not achieved good control of their PKU with diet alone.

The treatment involves receiving subcutaneous injections of Palynziq at different doses (2.5 mg, 10 mg, or 20 mg) using pre-filled syringes. Some participants will receive the medication while others will continue with dietary management only. The study will last approximately 215 days, during which participants will need regular medical check-ups and blood tests to monitor their condition.

Throughout the study, healthcare providers will monitor participants’ health through various tests and examine how well the medication helps control blood protein levels. An adult must be present to observe the participant for at least one hour after each injection. The study will also track how the treatment affects participants’ ability to include more protein in their diet.

]]> Study to Evaluate mRNA-3210 for Safety and Tolerability in Patients with Phenylketonuria https://clinicaltrials.eu/trial/study-to-evaluate-mrna-3210-for-safety-and-tolerability-in-patients-with-phenylketonuria/ Wed, 29 Apr 2026 14:27:15 +0000 https://clinicaltrials.eu/trial/study-to-evaluate-mrna-3210-for-safety-and-tolerability-in-patients-with-phenylketonuria/ This clinical trial is focused on studying a condition called Phenylketonuria (PKU), which is a rare genetic disorder that affects how the body processes a substance called phenylalanine, found in many protein-containing foods. The study will use a new treatment called mRNA-3210, which is designed to help manage PKU by providing the body with instructions to produce a specific enzyme that helps break down phenylalanine. This treatment is given through an injection into the vein.

The purpose of the study is to evaluate the safety and tolerability of mRNA-3210 in people with PKU. Participants will receive different doses of the treatment to find the most suitable dose. The study will monitor how the body responds to the treatment and any side effects that may occur. Participants will have regular check-ups and tests to assess their health and the treatment’s effects over the course of the study.

In addition to mRNA-3210, the study will also involve other medications such as Hydroxyzine Hydrochloride, Buclizine Hydrochloride, Paracetamol (also known as acetaminophen), Codeine Phosphate, Ibuprofen Lysine, Pseudoephedrine Hydrochloride, Cetirizine Dihydrochloride, Fexofenadine, Famotidine, and Diphenhydramine. Some participants may receive a placebo instead of the active treatment. The study aims to gather information on how these medications interact with mRNA-3210 and their overall impact on managing PKU.

]]> Study on the Effectiveness and Safety of SYNB1934 for Adults with Phenylketonuria (PKU) https://clinicaltrials.eu/trial/study-on-the-effectiveness-and-safety-of-synb1934-for-adults-with-phenylketonuria-pku/ Wed, 29 Apr 2026 14:25:22 +0000 https://clinicaltrials.eu/trial/study-on-the-effectiveness-and-safety-of-synb1934-for-adults-with-phenylketonuria-pku/ This clinical trial is focused on studying a condition called Phenylketonuria (PKU), a rare genetic disorder that affects how the body processes a substance called phenylalanine, which is found in many foods. The study is testing a new treatment known as SYNB1934v1, which is a specially modified strain of bacteria called Escherichia coli. This bacteria is designed to help reduce the levels of phenylalanine in the blood. The treatment is given in the form of a powder that is mixed with water and taken by mouth.

The purpose of the study is to evaluate the effectiveness and safety of SYNB1934v1 in people with PKU. The study is divided into different parts. Initially, participants will receive increasing doses of the treatment to find the most effective dose. After this, there will be a period where participants will be randomly assigned to continue with the treatment or switch to a placebo. This helps researchers understand how well the treatment works compared to no treatment. Finally, there will be an open-label period where all participants will receive the treatment to further assess its safety and tolerability.

In addition to SYNB1934v1, some participants may also receive other medications like Ondansetron, which is used to prevent nausea, and Esomeprazole, a medication that reduces stomach acid. These medications are given to manage any side effects that might occur during the study. The study will last for several weeks, and participants will be monitored closely to ensure their safety and to gather information on how the treatment affects their phenylalanine levels.

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