BH4 treatment in Phenylketonuria - comparing different practices of dosing

Conditions: Phenylketonuria (PKU)

Registration Number: NL-OMON25048

Lead Sponsor: niversity Medical Center Groningen

Brief Summary: Not available

Detailed Description: Not available

Recruitment & Eligibility

Status: Pending

Sex: Not specified

Target Recruitment: 28

Inclusion Criteria

In order to be eligible to participate in this study, a subject must meet all of the following criteria:
1. Diagnosed with phenylketonuria by newborn screening.
2. Diagnosed as a BH4-responder after a 48-h BH4 loading test and a treatment trial
3. Currently uses sapropterin as part of treatment (with a minimum of three months)
4. Age = 4 years
5. Good metabolic control for the previous 6 months, meaning 75% of the Phe levels are within therapeutic target levels with a minimum of four values.

Exclusion Criteria

A potential subject who meets any of the following criteria will be excluded from participation in this study:
Pregnancy, planning pregnancy or lactation

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
The primary outcome of the study is the comparison of Phe levels between the three treatment regimen. The mean, mean standard deviations (SD) and mean coefficient of variation (CV) of the blood phenylalanine concentrations measured 6 times a day of 2 consecutive days, will be compared for 3 different dosage regimen.

Secondary Outcome Measures

Name	Time	Method
-The mean SD and CV of the blood tyrosine concentrations measured 6 times a day of 2 consecutive days, compared for 3 different dosage regimen. <br>-The mean SD and CV of the blood phenylalanine/tyrosine ratio measured 6 times a day of 2 consecutive days, compared for 3 different dosage regimen. <br>-Time of highest and lowest Phe level during the day<br>-(When feasible: the kinetics of dried blood spot pterin concentrations).