Phenylketonuria Clinical Trials

23 recruitingLast updated: June 17, 2026

There are 23 actively recruiting phenylketonuria clinical trials across 18 countries. Studies span Not Applicable, Phase 1, Phase 2, Phase 3, Early Phase 1, Phase 4. Top locations include Dallas, Texas, United States, Portland, Oregon, United States, Pittsburgh, Pennsylvania, United States. Updated daily from ClinicalTrials.gov.


Phenylketonuria Trials at a Glance

23 actively recruiting trials for phenylketonuria are listed on ClinicalTrialsFinder across 6 cities in 18 countries. The largest study group is Not Applicable with 7 trials, with the heaviest enrollment activity in Dallas, Portland, and Pittsburgh. Lead sponsors running phenylketonuria studies include BioMarin Pharmaceutical, Otsuka Pharmaceutical Development & Commercialization, Inc., and Emory University.

Browse phenylketonuria trials by phase

Treatments under study

About Phenylketonuria Clinical Trials

Looking for clinical trials for Phenylketonuria? There are currently 12 studies actively recruiting participants. Clinical trials offer access to new treatments before they are widely available, and every approved therapy in use today was first tested through a clinical trial.

Below you can browse trials, sign up for alerts when new Phenylketonuria trials open, and view eligibility criteria for each study. Each listing includes the study phase, locations, and enrollment details.

Frequently Asked Questions

Common questions about Phenylketonuria clinical trials

A clinical trial is a carefully designed research study that tests new medical treatments, drugs, devices, or approaches in human volunteers. Every approved medication and treatment available today was proven safe and effective through clinical trials.

All clinical trials are reviewed and approved by Institutional Review Boards (IRBs) — independent committees that evaluate patient safety. Trials follow strict protocols, and your health is monitored closely throughout. You can withdraw at any time.

Not necessarily. Many trials compare the new treatment against the current standard of care, meaning all participants receive active treatment. When placebos are used, they are typically combined with standard treatment, not given alone. The trial description will always specify the design.

Under the Affordable Care Act, most private insurers are required to cover routine patient care costs during a clinical trial. The sponsor typically covers the investigational treatment itself. Medicare also covers routine costs for qualifying trials.

Yes. Participation is completely voluntary. You can withdraw at any time, for any reason, without it affecting your access to standard medical care.

Each trial has specific eligibility criteria — including age, diagnosis, disease stage, prior treatments, and general health. Browse the trials listed above and check their eligibility sections. You can also contact the trial site directly to discuss your situation.

Showing 120 of 23 trials

Recruiting
Phase 1

A Study to Evaluate Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of AG-181 in Subjects With Phenylketonuria

Phenylketonuria
Agios Pharmaceuticals, Inc.20 enrolled2 locationsNCT07241234
Recruiting
Phase 3

A Study of Sepiapterin in Participants With Phenylketonuria (PKU)

Phenylketonuria
PTC Therapeutics56 enrolled8 locationsNCT06302348
Recruiting
Not Applicable

Educational, Social Support, and Nutritional Interventions and Their Cumulative Effect on Pregnancy Outcomes and Quality of Life in Teen and Adult Women With Phenylketonuria

PregnancyPhenylketonuria
Emory University200 enrolled1 locationNCT01659749
Recruiting

Multiomics Approach in Adult Patients With Phenylketonuria

Phenylketonuria (PKU)
University Hospital, Tours149 enrolled15 locationsNCT07484945
Recruiting
Phase 3

A Study of JNT-517 in Participants With Phenylketonuria (PKU)

Phenylketonuria
Otsuka Pharmaceutical Development & Commercialization, Inc.120 enrolled25 locationsNCT06971731
Recruiting
Phase 3

A Long-Term Study of JNT-517 in Participants With Phenylketonuria

Phenylketonuria (PKU)
Otsuka Pharmaceutical Development & Commercialization, Inc.240 enrolled12 locationsNCT06628128
Recruiting
Phase 2

A Phase 2 Study of JNT-517 in Adolescent Participants With Phenylketonuria

Phenylketonuria (PKU)
Otsuka Pharmaceutical Development & Commercialization, Inc.10 enrolled7 locationsNCT06637514
Recruiting
Not Applicable

Effect of Different Meal Types Given Before Exercise on Plasma Amino Acid Levels and Metabolic Control Parameters in Classical Phenylketonuria Patients Undergoing Aerobic and Resistance Exercises

Phenylketonuria
Hacettepe University10 enrolled1 locationNCT07526909
Recruiting

A Long-term, Post-marketing Safety Study of Palynziq in Patients With PKU (PALace)

Phenylketonuria (PKU)
BioMarin Pharmaceutical450 enrolled26 locationsNCT05813678
Recruiting

A Global, Multicenter Study to Assess Maternal, Fetal and Infant Outcomes of Exposure to Palynziq® (Pegvaliase) During Pregnancy and Breastfeeding

Phenylketonuria, Maternal
BioMarin Pharmaceutical50 enrolled4 locationsNCT05579548
Recruiting

A Long Term, Post-marketing Study of Immune Response in Patients Receiving Palynziq Treatment for PKU (PALisade)

Phenylketonuria (PKU)
BioMarin Pharmaceutical200 enrolled11 locationsNCT06305234
Recruiting
Not Applicable

Impact of Phenylalanine Elevations on Brain and Cognition in Adult PKU Carriers

HealthyCarrier of Phenylketonuria
University of Missouri-Columbia36 enrolled1 locationNCT07220265
Recruiting
Early Phase 1

Safety and Efficacy Study of NGGT002 in PKU Adult Subjects

Phenylketonurias
The First Affiliated Hospital of Bengbu Medical University15 enrolled1 locationNCT06061614
Recruiting

Nutritional Impacts of Palynziq on Patients With Phenylketonuria (PKU)

Phenylketonurias
Emory University45 enrolled2 locationsNCT04404530
Recruiting
Not Applicable

Development of Novel Psychological Assessment Tools and Anxiety Intervention for Phenylketonuria

Phenylketonurias
University of Missouri-Columbia30 enrolled1 locationNCT06560736
Recruiting
Not Applicable

GMP Powdered Substitutes in PKU and TYR

PhenylketonuriaTyrosinemia
Nutricia UK Ltd40 enrolled1 locationNCT06941532
Recruiting
Phase 1Phase 2

AAV Gene Therapy Clinical Study in Adult Classic PKU (PHEdom)

Phenylketonurias
NGGT INC.12 enrolled5 locationsNCT06332807
Recruiting

Brain Aging in Phenylketonuria

Phenylketonuria (PKU)
Insel Gruppe AG, University Hospital Bern90 enrolled1 locationNCT06969209
Recruiting

Metabolic Control and Patient Well-being in Phenylketonuria: do Guidelines Make a Difference?

Phenylketonurias
University Children's Hospital, Zurich200 enrolled1 locationNCT05128149
Recruiting
Not Applicable

Effect of Large Neutral Amino Acids in Adults With Classical Phenylketonuria

Brain DiseasesMetabolic DiseasePhenylketonurias+5 more
Rigshospitalet, Denmark30 enrolled2 locationsNCT06337864