Recruiting
Phase 1
Phase 2

Pegtibatinase

Sponsor:

Travere Therapeutics, Inc.

Code:

NCT03406611

Conditions

Homocystinuria

Eligibility Criteria

Sex: All

Age: 5 - 65

Healthy Volunteers: Not accepted

Interventions

Pegtibatinase

Placebo

Study Details

Brief summary:

Researchers are looking for a better way to treat people who have classical homocystinuria (HCU), a rare condition that is passed down by parents (or "genetic condition"). It is caused by changes in the cystathionine beta-synthase (or "CBS") gene and prevents an enzyme from working correctly in the body. This enzyme breaks down a substance called homocysteine (from dietary methionine found in protein) and keeps both homocysteine and methionine at normal levels. When this enzyme is not working, homocysteine and methionine build up in the blood, which spreads into different tissues of the body and stops these body tissues from working normally.

People with HCU can experience problems with vision, bones, blood vessels, and cognitive function (the ability to think, learn, and remember). Treatments available for HCU, such as a low protein diet and betaine (Cystadane®), help reduce homocysteine levels. The diet is a low methionine diet and a methionine-free protein supplement (a product that provides extra protein to help meet daily protein needs). These treatments are either not sufficient or are hard to take for many patients.

Pegtibatinase was developed by scientists to be a version of the CBS enzyme that can be given to people with HCU. Researchers believe that giving pegtibatinase to people with HCU already getting medical treatment (or "standard of care") may reduce their homocysteine levels.

This study is split into 7 different groups getting different amounts of drug. The first 6 groups have already finished the study.

Group 7 plans to enroll participants from the US (virtual and in-person), France, and Qatar.

Conditions

Homocystinuria

Study ID

NCT03406611

Start date

Jan 22, 2019

Status verified date

Jul, 2026

Completion date

Jul, 2027

Anticipated

Primary completion date

Jul, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 5 - 65

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Age

  • Cohort 7 (currently enrolling): ≥5 to <12 years of age.
  • Completed Cohorts 1-6: ≥12 to 65 years of age.
  • Diagnosis of classical homocystinuria (HCU)

  • Cohort 7 (currently enrolling): Diagnosis based on clinical, biochemical, and/or molecular genetic testing.
  • Completed Cohorts 1-6: Genetically confirmed cystathionine beta-synthase (CBS)-deficient HCU.
  • Plasma total homocysteine (tHcy)

  • Cohort 7 (currently enrolling): Plasma tHcy ≥50 μM at Screening.
  • Completed Cohorts 1-6: Plasma tHcy ≥50 μM at Screening and documented historical plasma tHcy ≥80 μM.
  • Willing and able (or parent/legal guardian willing and able) to provide informed consent/assent and comply with study procedures.
  • Willing to maintain a generally stable standard-of-care treatment regimen, including dietary management and HCU-related therapies, unless changes are medically necessary.
  • Participants of childbearing potential must have a negative pregnancy test before study treatment and agree to use protocol-specified contraception, if applicable.

Exclusion Criteria:

Cohort 7 only:

  • Diagnosis of Marfan syndrome, methylenetetrahydrofolate reductase (MTHFR) deficiency, or a disorder of cobalamin metabolism.
  • History of a major thrombotic event within the previous 6 months.
  • Body weight <15 kg.

All Cohorts:

  • Previous treatment with pegtibatinase or pegtarviliase)
  • Participation in a pegtibatinase clinical study.
  • Receipt of another investigational drug or investigational medical device within 30 days before Screening or planned use during study participation.
  • Use of injectable polyethylene glycol (PEG)-containing medications (other than pegtibatinase or PEG-containing vaccines) within 3 months before Screening or during study participation.
  • Known hypersensitivity to pegtibatinase or a history of severe hypersensitivity to a PEG-containing product.
  • Active HIV, hepatitis B, or hepatitis C infection.
  • History of organ transplantation or immunosuppressive therapy.
  • Clinically significant medical conditions that could interfere with study participation or participant safety.
  • Pregnant or breastfeeding, or planning to become pregnant during study participation.
  • Major surgery planned during the study period.
  • Any condition that could prevent the participant from complying with study procedures or completing the study.

Study Design

Enrollment

39 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

active comparator: Pegtibatinase (Cohort 1-6)

Double-Blind Treatment Cohorts (≥12 to ≤65 years)

placebo comparator: Placebo (Cohort 1-6)

Double-Blind Treatment Cohorts (≥12 to ≤65 years)

experimental: Pegtibatinase (Cohort 7)

Pediatric Open-label Treatment Cohort (≥5 to <12 years)

Interventions

Pegtibatinase

Pegtibatinase sterile solution for subcutaneous injection

Placebo

Normal saline for subcutaneous injection

Primary outcome measure

  • Incidence of AEs [ Time Frame: • Cohorts 1-6: Through double-blind study completion, approximately 10 months per patient • Cohort 7: First dose through End of Treatment (up to 32 weeks) ]
  • Anti-pegtibatinase antibodies [ Time Frame: • Cohorts 1-6: Through double-blind study completion, approximately 10 months per patient • Cohort 7: First dose through End of Treatment (up to 32 weeks) ]
  • Anti-PEG antibodies [ Time Frame: • Cohorts 1-6: Through double-blind study completion, approximately 10 months per patient • Cohort 7: First dose through End of Treatment (up to 32 weeks) ]
  • Incidence of hypermethioninemia (Cohort 7 only) [ Time Frame: First dose through End of Treatment (up to Week 32) ]
  • Incidence of hypomethioninemia (Cohort 7 only) [ Time Frame: First dose through End of Treatment (up to Week 32) ]
  • The proportion of participants requiring dietary protein rescue (Cohort 7 only) [ Time Frame: First dose through End of Treatment (up to Week 32) ]

Central Contacts and Locations

Central contacts

Travere Call Center

1-877-659-5518medinfo@travere.com

Locations

Science 37 - Virtual Site

Recruiting

Morrisville, North Carolina, United States, 27560

More Information

Sponsor

Travere Therapeutics, Inc.

Last update posted

Aug 10, 2026

Last verified

Jul, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by Travere Therapeutics, Inc. on 2026-08-10.