PhenylketonuriaNCT06941532
GMP Powdered Substitutes in PKU and TYR
A study testing GMP Intervention Product in people with Phenylketonuria and Tyrosinemia, run by Nutricia UK Ltd at 1 site in United Kingdom.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 3 years and older
- Conditions the study is for
- Phenylketonuria, Tyrosinemia
- What is being tested?
- GMP Intervention Product
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 20 May 2025to 31 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 3 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United Kingdom1 site, 1 recruiting
- Recruiting
Birmingham Women and Children's Hospital
Birmingham
About this study
Official title: Evaluating the Adherence, Tolerance, Acceptability and Safety of New GMP-based Powdered Protein Substitutes in PKU and TYR: a Case Study Series
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.
- Conditions
- Phenylketonuria, Tyrosinemia
- Being tested
- GMP Intervention Product
- Medical subject headings
- Phenylketonurias, Tyrosinemias
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
GMP Intervention ProductDietary supplement
Condition specific GMP based intervention product
| Study group | Role | What they receive |
|---|---|---|
| GMP intervention product | Experimental | Not described Receives: Dietary Supplement: GMP Intervention Product |
What is being measured
The primary outcome is the main question the study is designed to answer.
Gastro-intetsinal tolerance
GI tolerance will be recorded by the Dietitian at baseline on Day 1 and at the end of the case study period (Day 29). GI tolerance will be recorded using a standardised questionnaire to capture perceived severity (none, mild, moderate or severe) of common gastrointestinal symptoms (diarrhoea, constipation, bloating, abdominal discomfort, vomiting and nausea). Information about appearance of stools will also be collected using the Bristol Stool Chart© at the same time points.
Measured: Measured at baseline (day 1) and end of intervention (day 29)
Secondary outcomes (6)
Acceptability
Acceptability (ease of use and liking) of the patients' usual protein substitute and the study product will be assessed by the Dietitian at baseline (Day 1) and the end of the case study period (Day 29) by a series of questions posed to the patient and/or parent/caregiver. Acceptability questions will assess the patient's sensory experience, ease of use, tolerance, and overall self-rated acceptability on a 5-point Likert scale.
Measured: Measured at baseline (day 1) and end of intervention (day 29)
Compliance
Compliance with the recommended intake of the patients' usual protein substitute (during baseline) and with the study product (during the case study period) will be assessed by the Dietitian at baseline (Day 1) and at the end of the case study (Day 29). Patients and/or parents/caregivers will be asked to recall the amount of their protein substitute taken in the past 24 hours and on average. This will be compared to the amount recommended to be consumed by their Dietitian. The daily amount prescribed by the Dietitian managing the patient's care will be recorded at the start of the case study and any changes to this prescription during the case study will also be noted.
Measured: Measured at baseline (day 1) and end of intervention (day 29)
Blood phenylalanine, blood tyrosine and other amino acid levels
Dietitians will be asked to record recent phenylalanine, tyrosine and other amino acid levels (and subsequent reference ranges) that are taken as part of normal clinical practice on Day 1 and at the end of the case study (Day 29), performed as a part of their routine care. Dietitians will also be asked to describe the patient's metabolic control during the case study period.
Measured: Day 1 (baseline) and day 29 (end of intervention)
Anthropometry
For safety purposes, at baseline (Day 1) and at the end of the case study (Day 29), body weight (kg) will be measured where possible using standard methods, recorded to the nearest 0.1kg using a weighing scale without heavy clothing. Height will also be measured, using standard methods, recorded to the nearest 0.1cm (at baseline only) and used to calculate body mass index (BMI, kg/m2).
Measured: Day 1 (baseline) and day 29 (end of intervention)
Patient history
A detailed patient history will be recorded at baseline to assess previous compliance to protein substitutes, relevant medical and clinical issues, medication(s) prescribed, and any other relevant information related to the patient's condition or dietary management.
Measured: Day 1 (baseline) and day 29 (end of intervention)
Safety/ Adverse Events
All adverse events will be recorded, throughout the case study.
Measured: Throughout the case study series (day 1 to day 29).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Apr 2025
- Study start20 May 2025
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PhenylketonuriaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Nutricia UK Ltd
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Gary Hubbard, Dr, Study director, Nutricia UK Ltd
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06941532
- Sponsor's protocol ID
- GMP2024
- Status last verified
- Dec 2025
- First submitted
- 4 Apr 2025
- Last updated
- 19 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 19 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluating the Adherence, Tolerance, Acceptability and Safety of New GMP-based Powdered Protein Substitutes in PKU and TYR: a Case Study Series
- ClinicalTrials.gov ID
- NCT06941532
- Acronym / sponsor ID
- GMP2024
- Conditions
- Phenylketonuria, Tyrosinemia
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Nutricia UK LtdIndustry (pharma, biotech, devices)
- Study start
- 20 May 2025 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 23 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| GMP intervention product | Experimental | Dietary Supplement: GMP Intervention Product |
Who may qualify
- Ages
- 3 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (7 listed)
- 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
Key exclusion criteria (6 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| GMP Intervention ProductCondition specific GMP based intervention product | Dietary supplement | GMP intervention product |
Primary outcome
Gastro-intetsinal tolerance
Time frame: Measured at baseline (day 1) and end of intervention (day 29)
GI tolerance will be recorded by the Dietitian at baseline on Day 1 and at the end of the case study period (Day 29). GI tolerance will be recorded using a standardised questionnaire to capture perceived severity (none, mild, moderate or severe) of common gastrointestinal symptoms (diarrhoea, constipation, bloating, abdominal discomfort, vomiting and nausea). Information about appearance of stools will also be collected using the Bristol Stool Chart© at the same time points.
6 secondary outcomes
Acceptability
Time frame: Measured at baseline (day 1) and end of intervention (day 29)
Compliance
Time frame: Measured at baseline (day 1) and end of intervention (day 29)
Blood phenylalanine, blood tyrosine and other amino acid levels
Time frame: Day 1 (baseline) and day 29 (end of intervention)
Anthropometry
Time frame: Day 1 (baseline) and day 29 (end of intervention)
Patient history
Time frame: Day 1 (baseline) and day 29 (end of intervention)
Safety/ Adverse Events
Time frame: Throughout the case study series (day 1 to day 29).
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 19 Dec 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Gary Hubbard, Dr study director
Nutricia UK Ltd
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing GMP Intervention Product in people with Phenylketonuria and Tyrosinemia, run by Nutricia UK Ltd at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 19 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Ellen Taylor (07900724091, ellen.taylor@nutricia.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Gastro-intetsinal tolerance (time frame: Measured at baseline (day 1) and end of intervention (day 29)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 Dec 2025.