Protein Requirements in Adults With Phenylketonuria (PKU)

Study Overview
=================
Brief Summary
-----------------
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.

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

Conditions
-----------------
Phenylketonuria

Intervention / Treatment
-----------------
* Dietary Supplement: Free amino acids intake


Participation Criteria
=================
Eligibility Criteria
-----------------
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

Ages Eligible for Study
-----------------
Minimum Age: 19 Years
Maximum Age: 50 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Supportive Care
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Protein intake<br>Free amino acids vs. Glycomacropeptide (GMP) | Dietary Supplement: Free amino acids intake<br>* 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).<br>* Other names: glycomacropeptide (GMP) intake;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 13 Co2 production | Breath samples will be collected during the study to measure the rate of oxidation of tracer in the expired breath. | 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. | 
| Lysine flux | Urine samples will be collected during the study to measure the flux enrichment in urine. | 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. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Phenylalanine concentrations | Phenylalanine concentrations will be measured in blood. | One sample (at 6th meal) after starting of the tracer protocol. Data will be reported an average of 2 years. | 
| Tyrosine concentrations | Tyrosine concentrations will be measured in blood. | One sample (at 6th meal) after starting of the tracer protocol. Data will be reported an average of 2 years. | 
| 16 other amino acids | 16 other amino acids will be measured in blood. | One sample (at 6th meal) after starting of the tracer protocol. Data will be reported an average of 2 years. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Phenylketonuria, PKU, Phenylalanine metabolism, Protein requirements, Indicator Amino acid Oxidation, Stable isotopes, GMP, Glycomacropeptide