Evaluation of Low Phenylalanine Formulas

Not Applicable

Active, not recruiting

• Conditions: Phenylketonurias
• Interventions: Dietary Supplement: L-AA; Dietary Supplement: Glytactin

• Registration Number: NCT06332105
• Lead Sponsor: Ajinomoto Co., Inc.

Brief Summary

Ajinomoto Cambrooke has developed a PKU protein substitute that is a proprietary blend of purified Glycomacropeptide (GMP) and essential amino acids, under the brand name Glytactin®. One serving of such Glytactin® products contains 20mg or less of Phenylalanine (Phe). The aim of the proposed study is to use this purified GMP-AA-based protein substitute, with less Phe per gram of protein equivalent than other commercially available products, in children with PKU at 100% of their protein substitute intake and evaluate its efficacy and the change in blood Phe in comparison to Phe-free L-AA-based protein substitutes.

Detailed Description

Study Design This is a 2-stage, 15-week randomized crossover trial. The randomized crossover design was chosen as it reduces the influence of differences among individuals; and it offers statistical efficiency (requires fewer subjects than non-crossover designs).

In summary, 2 groups of 9 participants each will be assigned to either (1) sequence 1: take GMP-AA-based PS for the first 4 weeks and then take only L-AA-based Protein Substitute for 4 weeks, or (2) take only L-AA-based Protein Substitute for the first 4 weeks and then take GMP-AA-based PS for 4 weeks. At the end of the first 4 weeks, a 2-week washout period will follow with both groups only consuming L-AA-based PS. Randomization will be generated by a block randomization system and the random order will be kept within a sealed envelope.

Primary research objective The principal research objective of this study is to evaluate the effect on Phe levels of a low-Phe diet combined with a purified GMP-AA-based protein substitute (containing 1 mg Phe/g Protein Equivalent), in the treatment of paediatric patients with PKU.

Secondary research objectives The secondary objectives of the study aim to investigate whether there are any differences between the GMP-AA-based protein substitute and L-AA-based protein Substitute in the frequency and quantity of protein substitute intake, if any GI (gastrointestinal) symptoms occur with ingestion of the GMP-AA-based protein substitute, effect on satiety (hunger) and mood and any differences in anthropometric data.

Study Timeline

• Study Start: 2023-01-30
• Study First Submitted: 2024-03-20
• Study First Submitted QC: 2024-03-25
• Study First Posted: 2024-03-27
• Status Verified: 2024-04
• Last Update Submitted: 2024-04-12
• Last Update Posted: 2024-04-15
• Primary Completion: 2025-01
• Study Completion: 2025-04

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 19

Inclusion Criteria

• Patients with PKU, aged 5 to 16 years of age, currently compliant with protein restricted diet and L-AA- and/or GMP-AA-based protein substitute willing to switch to a GMP-AA-based only product for 4 weeks.

  • 2 out of 4 last blood Phe levels within target range (i.e. 50%): Target range 120-360µmol/l <12 years Target range 120-600µmol/l >12 years

Exclusion Criteria

• • Milk protein allergy

  • Pregnancy
  • Severe medical diagnosis not related to PKU
  • Treatment with Sapropterin hydrochloride (KUVAN)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Sequence BA: L-AA -> GMP-AA	L-AA	After an initial washout period of 2 weeks, participants randomised to Sequence BA will consume L-AA for 3 months whilst keeping a food diary and sending blood spots for twice weekly analysis. At the end of 3 months there is a further 2 week washout period with L-AA, after which the participant will consume GMP-AA for 3 months whilst keeping a food diary and sending blood spots for twice weekly analysis.
Sequence AB: GMP-AA -> L-AA	Glytactin	After an initial washout period of 2 weeks, participants randomised to Sequence AB will consume GMP-AA for 3 months whilst keeping a food diary and sending blood spots for twice weekly analysis. At the end of 3 months there is a further 2 week washout period with L-AA, after which the participant will consume L-AA for 3 months whilst keeping a food diary and sending blood spots for twice weekly analysis.

Primary Outcome Measures

Name	Time	Method
Change in blood Phe in	16 weeks	Change in blood Phe in subjects ingesting purified GMP-AA-protein substitute compared with the change when ingesting L-AA-protein substitute

Trial Locations

Locations (2)

Birmingham Women and Children's Hospital; 🇬🇧 Birmingham, West Midlands, United Kingdom

Great Ormond Street Hospital for Children; 🇬🇧 London, United Kingdom