A Phase 2 Study of MZE782 in Adults With PKU (CIPheR)

July 2, 2026 updated by: Maze Therapeutics

A Phase 2, Randomized, Double-blind, Placebo-controlled, Dose-ranging Study to Evaluate the Safety, Tolerability, and Efficacy of MZE782 in Adults With Phenylketonuria (PKU)

The purpose of this study is to evaluate the safety, tolerability, and efficacy of MZE782 in adults with Phenylketonuria (PKU).

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

38

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Pennsylvania
      • Gordonville, Pennsylvania, United States, 17529
        • Recruiting
        • Clinic for Special Children

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Key Inclusion Criteria:

  • Males and females 18 to 75 years old
  • Clinical diagnosis of PKU
  • Willing and able to keep diet and protein intake consistent during the study
  • For some study groups, is willing and able to stop certain PKU medications before starting study treatment
  • For some study groups, may need to meet additional blood phenylalanine level or background-treatment requirements
  • Meets minimum blood phenylalanine level requirements for study group

Key Exclusion Criteria:

  • Is pregnant, breastfeeding, or planning to become pregnant or conceive a child during the study or within 90 days after the last dose
  • Medical conditions or abnormal test results that could make participation unsafe or make it difficult to complete study procedures or interpret study results
  • Has recently received another investigational drug
  • Is unable to swallow tablets or tolerate oral medication

Other inclusion/exclusion criteria defined in protocol apply.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: MZE782 Low Dose (Cohort 1A)
Drug: MZE782
Tablet, Low Dose
Drug: MZE782
Tablet, High Dose
Placebo Comparator: Placebo (Cohort 1A)
Other: Placebo
Tablet
Experimental: MZE782 High Dose (Cohort 1B)
Drug: MZE782
Tablet, Low Dose
Drug: MZE782
Tablet, High Dose
Placebo Comparator: Placebo (Cohort 1B)
Other: Placebo
Tablet
Experimental: MZE782 High Dose (Cohort 2)
Drug: MZE782
Tablet, Low Dose
Drug: MZE782
Tablet, High Dose
Placebo Comparator: Placebo (Cohort 2)
Other: Placebo
Tablet

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Safety and tolerability based on incidence of adverse events (AEs)
Time Frame: Week 0 to Week 17
Week 0 to Week 17
For Cohorts 1A and 1B: Absolute change in plasma Phe levels from Baseline to the mean of plasma Phe levels
Time Frame: Baseline and Weeks 2, 3, and 4
Baseline and Weeks 2, 3, and 4

Secondary Outcome Measures

Outcome Measure
Time Frame
For Cohorts 1A and 1B, analyzed separately: Geometric mean plasma concentrations of MZE782
Time Frame: Weeks 1, 2, 3, 4, 8, and 13
Weeks 1, 2, 3, 4, 8, and 13
For Cohorts 1A and 1B, analyzed separately: Absolute and Percent change in plasma Phe levels from Baseline to the mean of plasma Phe levels
Time Frame: Baseline up to Week 13
Baseline up to Week 13
For Cohorts 1A and 1B, analyzed separately: Proportion of participants with mean plasma Phe levels ≤600 μMol/L, ≤360 μMol/L, and ≤120 μMol/L
Time Frame: Baseline and Weeks 2, 3, 4, 8, 10, and 13
Baseline and Weeks 2, 3, 4, 8, 10, and 13

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Maze Therapeutics

Investigators

  • Study Director: Medical Director, Maze Therapeutics

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 23, 2026

Primary Completion (Estimated)

December 1, 2027

Study Completion (Estimated)

February 1, 2028

Study Registration Dates

First Submitted

July 2, 2026

First Submitted That Met QC Criteria

July 2, 2026

First Posted (Actual)

July 10, 2026

Study Record Updates

Last Update Posted (Actual)

July 10, 2026

Last Update Submitted That Met QC Criteria

July 2, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • MZE782-201

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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