A Long-term Extension Study to Assess the Long-term Safety and Efficacy of Pegtibatinase Treatment in Participants ≥5 to ≤65 Years of Age With Classical Homocystinuria (HCU) (ENSEMBLE)

An Open-Label, Phase 3 Long-Term Extension (LTE) Study To Assess The Safety, Tolerability, And Efficacy Of Treatment With Pegtibatinase In Participants With Classical Homocystinuria (HCU) Due To Cystathionine Beta Synthase Deficiency (ENSEMBLE)

Status

Enrolling by invitation

Phases

Phase 3

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT06431893

Acronym

ENSEMBLE

Enrollment

100

Registered

2024-05-29

Start date

2024-04-30

Completion date

2030-08-01

Last updated

2026-05-28

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Homocystinuria

Keywords

Classical homocystinuria, HCU, Cystathionine Beta Synthase Deficiency

Brief summary

The goal of this long-term extension (LTE) study is to evaluate the safety and efficacy of pegtibatinase in patients with classical homocystinuria (HCU). Patients who are active in the Phase 1/2 COMPOSE study or those who complete the 24 weeks of blinded treatment in the Phase 3 HARMONY are eligible to participate. Participants will be in this clinical study for a minimum of 108 weeks including: * a treatment period of up to 104 weeks * a 4-week safety follow-up period

Detailed description

Overall Design: This is a global, multicenter, single-arm, open-label study. Participants who meet all eligibility criteria may transition from other pegtibatinase studies and enroll into this LTE study for long-term safety, efficacy, and clinical assessments of pegtibatinase treatment. All participants will follow a protocol of self-administration of pegtibatinase unless exempted. During the study, pegtibatinase pharmacokinetic assessments will be conducted. An optional protein tolerance modification (PTM) sub-study will also be conducted for eligible participants.

Interventions

DRUGPegtibatinase

Pegtibatinase BIW

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

5 Years to 65 Years

Healthy volunteers

Inclusion criteria

* Participants active in the COMPOSE study or who completed the 24-week blinded period on study intervention (pegtibatinase or placebo) in the Phase 3 HARMONY study

Exclusion criteria

* Participant permanently discontinued from study intervention treatment in a previous pegtibatinase study due to serious AE (SAE) or intolerance

Design outcomes

Primary

Measure	Time frame	Description
Treatment-emergent AEs	Week 1 - Week 108	Incidence of treatment-emergent AEs
Hypermethioninemia	Week 1 - Week 108	Incidence of hypermethioninemia
Hypomethioninemia	Week 1 - Week 108	Incidence of hypomethioninemia
Dietary Protein Rescue	Week 1 - Week 108	Proportion of participants requiring dietary protein rescue for participants with hypomethioninemia

Secondary

Measure	Time frame	Description
Maximum Drug Concentration	Pharmacokinetic Assessment Period - 4 weeks & 8 weeks	Pegtibatinase pharmacokinetic parameters at steady state - maximum drug concentration \[Cmax\]
Area under the Curve within the Dosing Interval	Pharmacokinetic Assessment Period - 4 weeks & 8 weeks	Pegtibatinase pharmacokinetic parameters at steady state within the - area under the curve within the dosing interval \[AUC0-tau\]
Total Homocysteine (tHcy) Levels	Week 1 - Week 108	Relative and absolute changes from baseline in tHcy levels

Countries

Australia, Belgium, France, Germany, Ireland, Italy, Poland, Portugal, Qatar, Saudi Arabia, Spain, Turkey (Türkiye), United Kingdom, United States

Contacts

STUDY_DIRECTORMichael Imperiale, MD

Travere Therapeutics, Inc.

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: May 29, 2026