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Biological Variation of Phenylalanine in Patients With Hyperphenylalaninemia

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ClinicalTrials.gov Identifier: NCT01869972
Recruitment Status : Completed
First Posted : June 5, 2013
Last Update Posted : December 11, 2015
Sponsor:
Collaborators:
Information provided by (Responsible Party):

Study Description
Brief Summary:

Phenylketonuria (PKU) is a rare disease where the level of phenylalanine (one of the amino acids) in the body is greatly increased. High levels can cause brain damage, especially in babies and children. This brain damage can be prevented if a special low phenylalanine diet is started soon after birth. A new drug, sapropterin, can also lower phenylalanine levels in some patients. PKU therapy is monitored by measuring the blood phenylalanine every week, with the goal to keep the level within a target range. Recently, studies have suggested that the variation in the blood phenylalanine may be just as important as the absolute blood phenylalanine level for brain outcome.

The investigators will look at the variation in blood phenylalanine level over 24 hours to see how much the level changes. The investigators will measure this in patients with typical PKU who are compliant with the diet and in patients who are not compliant with the diet. The investigators will also measure this in patients with "mild" PKU who do not usually have as high levels of phenylalanine. Finally, the investigators will see if patients on sapropterin have lower variation.


Condition or disease
Phenylketonuria Hyperphenylalaninemia

  Show Detailed Description

Study Design

Study Type : Observational
Actual Enrollment : 32 participants
Observational Model: Case Control
Time Perspective: Prospective
Official Title: Biological Variation of Phenylalanine in Patients With Hyperphenylalaninemia
Study Start Date : May 2013
Primary Completion Date : December 2015
Study Completion Date : December 2015


Groups and Cohorts

Group/Cohort
Wide PHE group
Subjects prescribed diet alone to treat their PKU who have >1/3 of monitoring phenylalanine levels (with at least 3 levels measured) outside the target treatment range in the 6 months preceding enrolment. Target therapeutic range is 120 - 360 umol/L for age <12 years and 120 - 600 umol/L for age ≥ 12 years.
Target PHE group
Subjects prescribed diet alone to treat their PKU who have ≤ 1/3 of monitoring phenylalanine levels (with at least 3 levels measured) outside the target treatment range in the 6 months preceding enrolment. Target therapeutic range is 120 - 360 umol/L for age <12 years and 120 - 600 umol/L for age ≥ 12 years.
Kuvan(TM) group
Subjects on Kuvan(TM) (any dose for at least 3 months with no dosage change for most recent 1 month) ± diet therapy
Control group
Subjects with non-PKU hyperphenylalaninemia (maximum phenylalanine level 120 - 599 umol/L on no therapy).


Outcome Measures

Primary Outcome Measures :
  1. Standard deviation of blood phenylalanine level (sdPHE) [ Time Frame: 24 hour period ]
    16 to 17 blood phenylalanine levels will be measured over 24 hours. The standard deviation of those measurements will be the sdPHE.


Secondary Outcome Measures :
  1. Peak phenylalanine level [ Time Frame: 24 hour ]
    The highest blood phenylalanine level in the 24 hour period

  2. peak phenylalanine / tyrosine ratio [ Time Frame: 24 hours ]
    The highest blood phenylalanine / tyrosine ratio, with phenylalanine and tyrosine measured on the same sample


Eligibility Criteria

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Ages Eligible for Study:   4 Years and older   (Child, Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Metabolic and/or PKU clinic
Criteria

Inclusion Criteria:

• Subjects ≥4 years of age with hyperphenylalaninemia. Must have at least 1 documented blood phenylalanine level >600 µmol/L for study groups (Wide PHE, Target PHE, Kuvan groups) or >120 µmol/L for control group.

Exclusion Criteria:

  • Significant cognitive impairment (IQ <70 or clinical judgment).
  • Pregnancy
  • Other specific PKU therapies, including enzyme replacement therapy or any amino acid supplement designed to block uptake or transport of phenylalanine (i.e. large neutral amino acid mixtures)
  • Any intercurrent illness within the previous 5 days (any of fever, vomiting, diarrhea, decreased intake, upper respiratory tract infection).
Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01869972


Locations
Canada, Ontario
McMaster Children's Hospital
Hamilton, Ontario, Canada, L8S 4J9
Children's Hospital of Eastern Ontario
Ottawa, Ontario, Canada, K1H 8L1
Sponsors and Collaborators
Hamilton Health Sciences Corporation
McMaster Children's Hospital
Children's Hospital of Eastern Ontario
BioMarin Pharmaceutical
Investigators
Principal Investigator: Murray Potter, MD Hamilton Health Sciences Corporation
More Information

Responsible Party: Hamilton Health Sciences Corporation
ClinicalTrials.gov Identifier: NCT01869972     History of Changes
Other Study ID Numbers: PKUvar-01
First Posted: June 5, 2013    Key Record Dates
Last Update Posted: December 11, 2015
Last Verified: December 2015

Keywords provided by Hamilton Health Sciences Corporation:
PKU
phenylketonuria
hyperphenylalaninemia
Kuvan
sapropterin

Additional relevant MeSH terms:
Phenylketonurias
Brain Diseases, Metabolic, Inborn
Brain Diseases, Metabolic
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Amino Acid Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Metabolic Diseases