NCT05099640

A Study of PTC923 in Participants With Phenylketonuria

A Phase 3 Study of PTC923 in Subjects With Phenylketonuria

• Status: Completed
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 157 (actual)
• Sponsor: PTC Therapeutics · Industry
• Sex: All
• Age: —
• Healthy volunteers: Not accepted

Summary

The main purpose of this trial is to evaluate the efficacy of PTC923 in reducing blood phenylalanine (Phe) levels in participants with phenylketonuria as measured by mean change in blood Phe levels from baseline to Weeks 5 and 6 (that is, the average of each respective treatment dose 2-week period of double-blind treatment).

Detailed description

The study includes 2 parts: Part 1 and 2. Part 1 of the study tests for responsiveness to PTC923, with 14 days of open-label treatment with PTC923. At the end of treatment in Part 1, the mean change in blood Phe levels over the 14-day treatment period for all participants will be assessed against their pretreatment (baseline) blood Phe level. Participants ≥2 years of age who experience a \<15% reduction in blood Phe levels will be classified as non-responsive and participation in the study will be terminated. Participants (≥2 years of age) who experience a ≥15% reduction in blood Phe levels will continue into Part 2. Participants \<2 years of age who experience ≥15% reduction in blood Phe levels will be offered the option to enroll directly into an open-label extension Study PTC923-MD-004-PKU. Participants \<2 years of age who experience a \<15% reduction in blood Phe levels will be classified as nonresponsive, and participation in the study will be terminated. Following the minimum 14-day PTC923 washout period, all eligible participants will be randomized in Part 2 to receive either PTC923 or placebo. After 6 weeks of treatment with either PTC923 or placebo, participants will be offered the option to enter an open-label extension Study PTC923-MD-004-PKU (NCT05166161).

Conditions

• Phenylketonuria

Interventions

Type	Name	Description
DRUG	PTC923	PTC923 powder for oral use will be suspended in water or apple juice prior to administration.
DRUG	Placebo	Placebo matching to PTC923

Timeline

• Start date: 2021-09-30
• Primary completion: 2023-04-03
• Completion: 2023-05-03
• First posted: 2021-10-29
• Last updated: 2024-01-10
• Results posted: 2024-01-10

Locations

43 sites across 15 countries: United States, Australia, Brazil, Canada, Denmark, France, Georgia, Germany, Italy, Mexico, Netherlands, Portugal, Spain, Turkey (Türkiye), United Kingdom

Regulatory

• FDA-regulated drug study