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NCT Number: NCT03939052

Protein Requirements in Adults With Phenylketonuria (PKU)

Phenylketonuria (PKU) is an inherited inborn error of phenylalanine (PHE) metabolism caused by decreased activity of phenylalanine hydroxylase (PAH) enzyme. Therefore, PHE accumulates in plasma leading to mental problems. Treatment is a phenylalanine-restricted diet with sufficient protein. However, the optimum protein requirements are still unknown and compliance with diet is not satisfactory in PKU adults. A Previously established technique called indicator amino acid oxidation (IAAO) will be used to determine protein requirements from amino acid based formula vs. glycomacropeptide (GMP) in adults with PKU (≥ 19y). This study will help treat adults with enough protein ensuring maintenance of health.

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Key information

Conditions

Phenylketonuria Amino Acid Metabolism, Inborn Errors Brain Diseases Brain Diseases, Metabolic Brain Diseases, Metabolic, Inborn Central Nervous System Diseases Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Metabolic Diseases Metabolism, Inborn Errors Nervous System Diseases Nutritional and Metabolic Diseases Phenylketonurias

Age range

19 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

BC Children's Hospital Research Institute, University of British Columbia

Vancouver, British Columbia, V5Z4H4, Canada

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

-Adults more than 19 years of age who are diagnosed with PKU and clinically stable with no acute illness

Exclusion criteria

  • Adults with PKU under age 19 year
  • Adults diagnosed with PKU but are currently ill with a fever or cold

Treatment and study plan

Free amino acids intake

Dietary Supplement

Oral consumption of eight hourly experimental meals- -4 tracer free experimental meals containing a mixture of free amino acids and calories from protein free flavoured liquid, protein free cookies and corn oil -4 isotopically labeled experimental meals. The same protocol will be repeated with glycomacropeptide (GMP).

Other names: glycomacropeptide (GMP) intake

Primary outcomes

  1. 13 Co2 production

    Time frame: 8 hours (1 study day). 3 samples will collected as a baseline prior to isotope protocol and 6 samples after 2 hours and 30 minutes of starting the tracer protocol. Data will be reported an average of 2 years.

    Breath samples will be collected during the study to measure the rate of oxidation of tracer in the expired breath.

  2. Lysine flux

    Time frame: 8 hours (1 study day). 1 sample will collected as a baseline prior to isotope protocol and 2 samples after 2 hours and 30 minutes of starting the tracer protocol. Data will be reported an average of 2 years.

    Urine samples will be collected during the study to measure the flux enrichment in urine.

Secondary outcomes

  1. Phenylalanine concentrations

    Time frame: One sample (at 6th meal) after starting of the tracer protocol. Data will be reported an average of 2 years.

    Phenylalanine concentrations will be measured in blood.

  2. Tyrosine concentrations

    Time frame: One sample (at 6th meal) after starting of the tracer protocol. Data will be reported an average of 2 years.

    Tyrosine concentrations will be measured in blood.

  3. 16 other amino acids

    Time frame: One sample (at 6th meal) after starting of the tracer protocol. Data will be reported an average of 2 years.

    16 other amino acids will be measured in blood.

Sponsors and collaborators

Lead sponsor

University of British Columbia

Other

Collaborators

  • Vitaflo International, Ltd

Registry information

Official study title

Protein Requirements in Phenylketonuria (PKU) Patients Compared Using PKU Sphere™ | Glycomacropeptide (GMP) and an L-amino Acid-based Product

Important dates

Study start
2019
Primary completion
2021
Study completion
2023
First posted
May 6, 2019
Registry last updated
Jul 25, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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