Phase 2 Study of Glycomacropeptide Versus Amino Acid Diet for Management of Phenylketonuria
| Status: | Completed |
|---|---|
| Conditions: | Endocrine |
| Therapuetic Areas: | Endocrinology |
| Healthy: | No |
| Age Range: | 12 - 45 |
| Updated: | 8/26/2018 |
| Start Date: | September 2011 |
| End Date: | May 2016 |
Phase 2 Study of Glycomacropeptide vs. Amino Acid Diet for the Management of PKU
For individuals with Phenylketonuria (PKU), the investigators hypothesize that
glycomacropeptide will provide an acceptable form of low-phenylalanine dietary protein that
will improve dietary compliance, blood phenylalanine levels, cognitive function, and
ultimately quality of life compared with the usual amino acid based diet. The study is funded
by the Food and Drug Administration (FDA) Office of Orphan Products Development Grants
Program, R01 FD003711.
glycomacropeptide will provide an acceptable form of low-phenylalanine dietary protein that
will improve dietary compliance, blood phenylalanine levels, cognitive function, and
ultimately quality of life compared with the usual amino acid based diet. The study is funded
by the Food and Drug Administration (FDA) Office of Orphan Products Development Grants
Program, R01 FD003711.
Individuals with phenylketonuria (PKU) lack the enzyme phenylalanine hydroxylase that is
needed to metabolize the essential amino acid phenylalanine (phe). When eating a normal diet
they show an elevated level of phe in blood that is toxic to the brain. In order to prevent
brain damage and cognitive impairment, individuals with PKU must follow a lifelong, low-phe
diet that is restricted in natural foods and requires ingestion of a phe-free amino acid (AA)
formula. Most adolescents and adults with PKU find the AA formula unpalatable and go off the
diet resulting in elevated blood phe levels and neuropsychological deterioration.
Glycomacropeptide (GMP), an intact protein produced during cheese making, is uniquely suited
to a low-phe diet because it is the only known dietary protein that contains minimal phe.
Foods and beverages made with GMP are a palatable alternative to AA formula. The long term
goal is to assess the safety, efficacy and acceptability of GMP for the nutritional
management of PKU. The specific aim is to conduct a randomized, two-stage, 11-wk, crossover
trial comparing the GMP diet with the AA diet in 30 subjects with PKU ≥12 years of age
treated since birth with a low-phe AA diet. The sites are: University of Wisconsin-Madison,
Waisman Center (primary) and Harvard University, Children's Hospital Boston. Subjects will be
recruited and randomized to begin the first 3-wk of the study with either a low-phe diet in
which the majority of dietary protein is provided by GMP or AA medical foods and then, after
a 3-wk washout with intake of their usual diet, begin the second diet for 3-wk. Dietary
education will be provided in a 1-wk base period preceding initiation of each diet.
needed to metabolize the essential amino acid phenylalanine (phe). When eating a normal diet
they show an elevated level of phe in blood that is toxic to the brain. In order to prevent
brain damage and cognitive impairment, individuals with PKU must follow a lifelong, low-phe
diet that is restricted in natural foods and requires ingestion of a phe-free amino acid (AA)
formula. Most adolescents and adults with PKU find the AA formula unpalatable and go off the
diet resulting in elevated blood phe levels and neuropsychological deterioration.
Glycomacropeptide (GMP), an intact protein produced during cheese making, is uniquely suited
to a low-phe diet because it is the only known dietary protein that contains minimal phe.
Foods and beverages made with GMP are a palatable alternative to AA formula. The long term
goal is to assess the safety, efficacy and acceptability of GMP for the nutritional
management of PKU. The specific aim is to conduct a randomized, two-stage, 11-wk, crossover
trial comparing the GMP diet with the AA diet in 30 subjects with PKU ≥12 years of age
treated since birth with a low-phe AA diet. The sites are: University of Wisconsin-Madison,
Waisman Center (primary) and Harvard University, Children's Hospital Boston. Subjects will be
recruited and randomized to begin the first 3-wk of the study with either a low-phe diet in
which the majority of dietary protein is provided by GMP or AA medical foods and then, after
a 3-wk washout with intake of their usual diet, begin the second diet for 3-wk. Dietary
education will be provided in a 1-wk base period preceding initiation of each diet.
Inclusion Criteria:
- Identified PKU by newborn screening; started diet treatment before 1 mo age
- Diagnosis of classical or variant PKU with documented phenylalanine level of greater
than 600 umol/L at 7-10d of age
- Follows or willing to follow PKU diet and consume amino acid medical formula providing
more than 50% of protein needs
- Acceptance of glycomacropeptide foods determined prior to enrollment
Exclusion Criteria:
- Females who are pregnant or planning pregnancy
- Individuals with mental deficits due to untreated or poorly controlled PKU
- Individuals with any health condition deemed to interfere with participation
We found this trial at
2
sites
University of Wisconsin-Madison In achievement and prestige, the University of Wisconsin-Madison has long been recognized...
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