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RecruitingNCT07825883FreqPHEncyUpdated Sep 17, 2026

The Impact of Frequency of Home Phenylalanine Measurements on Metabolic Control in a Population of Patients With Classic Phenylketonuria

An interventional study of DBS Phe monitoring once weekly and DBS Phe monitoring once monthly in Phenylketonuria (PKU), sponsored by Michał Kania. Recruiting at 1 site in Poland. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-09-17.

Sponsored by Michał Kania · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
36
Allocation
Randomized
Ages
18 Years to 65 Years
Sex
All
01

Study summary

Recommendations regarding the frequency of phenylalanine level monitoring lack solid support from evidence derived from prospective randomized trials, including in the adult population with classic PKU. Current recommendations indicate that in adults (excluding the period of pregnancy planning and pregnancy itself), Phe levels should be assessed at least once a month or more frequently if additional indications exist. As part of this study, we plan to obtain, for the first time, high-quality data on the impact of Phe monitoring frequency on Phe control in adults. The primary objective of the study will be to assess the effect of the frequency (once a week versus once a month) of Phe level measurements on the metabolic control of phenylketonuria, as expressed by Phe concentration in DBS, in adult patients with the classic form of phenylketonuria.

02

Conditions studied

  • Phenylketonuria (PKU)

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Keywords

  • phenylketonuria
  • PKU
  • hyperphenylalaninemia
  • dried blood spot
  • DBS
  • phenylalanine
  • Phe
  • monitoring
03

Who can participate

Ages eligible
18 Years to 65 Years
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  1. Informed consent to participate in the study
  2. Male or female participants aged ≥18 and ≤65 years
  3. Clinical diagnosis of classic phenylketonuria (PKU) documented in the medical history by at least 2 measurements of blood phenylalanine concentration

    ≥600 μmol/l and a predicted PAH enzyme activity \<1% (GPV), requiring treatment with a low-protein diet supplemented with special low-phenylalanine amino acid mixtures

  4. Blood phenylalanine concentration in the range of 360-900 μmol/l during current therapy at the time of screening, and blood phenylalanine concentration in the range of 360-900 μmol/L during current treatment, based on the arithmetic mean of the last 3 Phe measurements from the participant's medical history (including the value from the screening)
  5. Ability and willingness, in the investigator's opinion, to comply with all requirements of the study.

Exclusion criteria

Exclusion Criteria:

  • 1. Patients who have not followed a phenylalanine (Phe)-restricted diet for 6 months prior to the start of the study or who are not willing to continue this diet 2. Phe concentration > 900 μmol/L in any measurement taken within 6 months prior to the start of the study 3. Drug or alcohol abuse 4. A person who, in the investigator's opinion, is unable or unwilling to comply with the study requirements. Persons who are legally incapacitated will not be eligible to participate in the study 5. Current participation in another clinical trial or use of any experimental drug within 30 days prior to screening 6. Planning a pregnancy or being pregnant 7. Confirmed diagnosis of primary BH4 deficiency, documented by the presence of pathogenic mutations in both alleles of the following genes: 6-pyroyl-tetrahydrobiopterin synthase, recessive guanosine triphosphate (GTP) cyclohydrolase, sepiapterin reductase, dihydropteridine quinonoid reductase, or pterin 4 alpha-carbinolamine dehydratase 8. Use of sapropterin, sepiapterin, or pegvaliaza concurrently or within 365 days prior to screening
04

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Crossover assignment
Masking
None (open label)
Enrollment
36 participants (estimated)

Study arms

  • Experimental
    Sequence 1

    Sequence 1 starts with intervention period 1 with DBS Phe measurements once a week for 24 weeks, followed by a 2-week wash-out period and intervention period 2 with DBS Phe measurements once a month for 24 weeks.

    Other: DBS Phe monitoring once weekly · Other: DBS Phe monitoring once monthly

  • Experimental
    Sequence 2

    Sequence 2 starts with intervention period 1 with DBS Phe measurements once a month for 24 weeks, followed by a 2-week wash-out period and intervention period 2 with DBS Phe measurements once a week for 24 weeks.

    Other: DBS Phe monitoring once weekly · Other: DBS Phe monitoring once monthly

Interventions

  • OtherDBS Phe monitoring once weekly

    In the intervention period participants will measure their Phe levels via DBS once a week as compared to once weekly.

  • OtherDBS Phe monitoring once monthly

    In the control period participants will measure their Phe levels via DBS once monthly.

05

What researchers measure

Primary outcomes

  1. Change in Phe concentration in the DBS measurement

    Change in Phe concentration in the DBS measurement from the baseline (O1) to the 5th and 6th months in each intervention period (average of measurements O140 and O168 \[measurements once a month\] OR O119 O168 \[measurements taken once a week\]).

    Time frame: from the baseline (O1) to the 5th and 6th months in each intervention period (average of measurements O140 and O168 [measurements once a month] OR O119 O168 [measurements taken once a week]).

06

Study locations

1 of 1 sites recruiting
  • Department of Diabetology, Internal Medicine, and Metabolic Diseases, Metabolic Diseases Clinic, University Hospital in Kraków
    Krakow, 30-688, Poland
    Recruiting
07

References and documents

Individual participant data

Plan to share: No — Sponsor requirement.

No publications or documents are linked to this record.

08

Registry details

Key details

Study ID
NCT07825883
Lead sponsor
Michał Kania
Collaborators
Jagiellonian University Medical College - Department and Clinic of Metabolic Diseases (Katedra i Klinika Chorób Metabolicznych UJ), Polskie Towarzystwo Wrodzonych Was Metabolizmu
Responsible party
Michał Kania (Acting Head of the Rare Metabolic Diseases Laboratory Chair of Metabolic Diseases Jagiellonian University Medical College, Kraków, Poland, Jagiellonian University) — Sponsor-investigator
First posted
Sep 17, 2026
Start date
Sep 11, 2026
Primary completion
Mar 31, 2028 (estimated)
Completion
Dec 31, 2028 (estimated)
Last update
Sep 17, 2026

Study contacts

Michal Kania, MD, PhD
Contact
mich.kania@uj.edu.pl
+48124002950
Michal Kania
principal investigator · Michał Kania

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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