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

NCT07825883 | Recruiting

• 1 other identifier: 1072.6120.1.16.2026
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief 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.

Conditions

Phenylketonuria (PKU)

Keywords

phenylketonuria; PKU; hyperphenylalaninemia; dried blood spot; DBS; phenylalanine; Phe; monitoring

Outcome Measures

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 \[measurements taken once a week\]).

  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]).

Study Arms (2)

Sequence 1

EXPERIMENTAL

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

Sequence 2

EXPERIMENTAL

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

DBS Phe monitoring once weekly OTHER

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

Sequence 1; Sequence 2

DBS Phe monitoring once monthly OTHER

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

Sequence 1; Sequence 2

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Informed consent to participate in the study
• Male or female participants aged ≥18 and ≤65 years
• 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
• 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)
• Ability and willingness, in the investigator's opinion, to comply with all requirements of the study.

You may not qualify if:

• \. 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

Sponsors & Collaborators

• Michał Kania: lead
• Polskie Towarzystwo Wrodzonych Was Metabolizmu: collaborator
• Jagiellonian University Medical College - Department and Clinic of Metabolic Diseases (Katedra i Klinika Chorób Metabolicznych UJ): collaborator

Study Sites (1)

Department of Diabetology, Internal Medicine, and Metabolic Diseases, Metabolic Diseases Clinic, University Hospital in Kraków

Krakow, 30-688, Poland

RECRUITING

MeSH Terms

Conditions

Phenylketonurias

Condition Hierarchy (Ancestors)

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; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Metabolic Diseases; Nutritional and Metabolic Diseases

Study Officials

• Michal Kania

  Michał Kania

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Michal Kania, MD, PhD

CONTACT

+48124002950; mich.kania@uj.edu.pl

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Acting Head of the Rare Metabolic Diseases Laboratory Chair of Metabolic Diseases Jagiellonian University Medical College, Kraków, Poland

Study Record Dates

• First Submitted: September 12, 2026
• First Posted: September 17, 2026
• Study Start: September 11, 2026
• Primary Completion (Estimated): March 31, 2028
• Study Completion (Estimated): December 31, 2028
• Last Updated: September 17, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

PL (1)