ClinicalTrials.gov record NCT06941532

GMP Powdered Substitutes in PKU and TYR

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Sep 6, 2026

Evaluating the Adherence, Tolerance, Acceptability and Safety of New GMP-based Powdered Protein Substitutes in PKU and TYR: a Case Study Series

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.
Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.
Age3 years old and older
SexAll
LocationUnited Kingdom
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This 29-day case-study series tests four powdered protein substitutes based on glycomacropeptide (GMP) in people with phenylketonuria (PKU) or tyrosinemia (TYR). After a 1-day baseline, participants use a study GMP product for 28 days while dietitians record gastrointestinal tolerance, acceptability, compliance, blood amino acid results taken in routine care, anthropometry, and any adverse events. The study is single-group and open (no masking). It includes children aged over 3 years and people.

What it is studying. Whether people with PKU or TYR can tolerate and accept GMP-based powdered protein substitutes, how well they can follow the prescribed intake, and whether use is associated with any safety signals or changes in routine blood amino acid measurements.

What the researchers hope to learn. To collect data on gastrointestinal tolerance, product acceptability, adherence to the recommended intake, routine blood phenylalanine/tyrosine and other amino acid measurements, body measurements, and safety (adverse events) associated with four GMP-based powdered protein substitutes.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

Four new GMP-based protein substitutes have been developed to support the dietary management of PKU and TYR. These products are powdered protein substitutes, low in phenylalanine and low in phenylalanine and tyrosine respectively, with a mix of glycomacropeptide (GMP), essential and non-essential amino acids, carbohydrates, fibres, fats (including DHA) and micronutrients. The proteins in these new protein substitutes are based on GMP, a peptide isolated from milk during cheese manufacturing and the only known naturally derived protein source low in phenylalanine and tyrosine. The GMP is supplemented with other amino acids which are naturally low or not present in GMP, as well as carbohydrates, fats, fibre and micronutrients. Studies to date have illustrated that PKU patients who replace their regular phenylalanine-free amino acid-based formula with GMP-based foods may have better diet compliance and prefer the taste whilst maintaining metabolic control. This series of case-studies aims to evaluate the gastrointestinal tolerance, acceptability, compliance, and safety of these four GMP based protein substitutes in both adults and children over 3 years. These case studies will last 29 days in total, including a 1-day baseline period followed by a 28-day intervention period. The case studies will be conducted across multiple specialist metabolic centres in the UK. A series of case studies is undertaken due to the rarity of these conditions, the diversity of patient types and the difficulty in recruiting these patients to trials.

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Dietary supplement
  • GMP Intervention Product

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

  • Male or female
  • Over 3 years of age
  • Patients diagnosed with any phenotype of PKU characterised by hyperphenylalaninaemia or patients diagnosed with tyrosinaemia
  • Have been compliant in taking at least one protein substitute, providing at least 15g protein equivalents, for at least 1 month prior to trial commencement
  • Have a prescribed daily phenylalanine or phenylalanine and tyrosine allowance for PKU or TYR respectively
  • Written or electronic informed consent from patient, and/or from parent/caregiver if applicable
  • Participants who are anticipated to be able to take at least one sachet of GMP Product per day

Exclusion criteria

  • Pregnant or lactating
  • Requiring parenteral nutrition
  • Major hepatic or renal dysfunction
  • Participation in other studies within 1 month prior to entry of this study
  • Allergy to any of the study product ingredients
  • Investigator concern around willingness/ability of patient or parent/caregiver to comply with protocol requirement

Study description and what participation involves

The registry record has no detailed description beyond the summary above.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

The case study lasts 29 days: a Day 1 baseline visit then a 28-day period using the powdered GMP protein substitute daily. You will meet with a dietitian at baseline and at Day 29 to complete questionnaires about gastrointestinal symptoms, product acceptability (taste and ease of use), and to record stool appearance using the Bristol Stool Chart. Dietitians will record recent routine blood phenylalanine, tyrosine and other amino acid results if available, measure weight (and height at baseline), monitor compliance with the product, and record any adverse events throughout the study.

How the study is structured. An interventional, single-group, open-label case-study series lasting 29 days (1 day baseline, 28 days intervention). Participants replace their usual protein substitute with a condition-specific GMP powdered product and are assessed by their dietitian at baseline and at the end of the 28-day period; adverse events are recorded throughout.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

  • The listed sites are in United Kingdom. Is any of them reachable for me, and does the study help with travel?
  • Which of the eligibility criteria would need to be checked with tests before I could join?

More on phenylketonuria

Clinical trials38 trials listed for phenylketonuriaEvery trial the registry lists for phenylketonuria, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in phenylketonuria researchLatest monthly update: September 2026. Includes: Diet supply gaps. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start
May 20, 2025
Primary completion
Dec 31, 2026 (estimated)
Study completion
Dec 31, 2026 (estimated)
Target enrollment
40 participants (estimated)
Last updated on registry
Dec 19, 2025
Data verified
Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor
Nutricia UK Ltd

Central study contact

If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.

Participating sites (1)

  • Birmingham Women and Children's HospitalRecruiting

    Birmingham · United Kingdom

Terms used on this page · explanations by MedicalUpdates.ai

baseline
Measurements taken at the start of the study, before any study treatment, so that later results can be compared with them.
informed consent
The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
Inclusion Criteria
The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Exclusion Criteria
The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

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