NCT05345171

Clinical Study of DTX301 AAV-Mediated Gene Transfer for Ornithine Transcarbamylase (OTC) Deficiency

A Phase 3, Randomized, Double-blind, Placebo-controlled Study of Adeno-associated Virus (AAV) Serotype 8 (AAV8)-Mediated Gene Transfer of Human Ornithine Transcarbamylase (OTC) in Patients With Late-onset OTC Deficiency

• Status: Active Not Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 32 (estimated)
• Sponsor: Ultragenyx Pharmaceutical Inc · Industry
• Sex: All
• Age: 12 Years
• Healthy volunteers: Not accepted

Summary

The primary objective is to evaluate the efficacy of DTX301 on the improvement of ornithine transcarbamylase (OTC) function by maintaining safe plasma ammonia levels.

Detailed description

This study is a Phase 3, randomized, double-blind, placebo-controlled study of DTX301 in patients with late-onset OTC deficiency 12 years of age and older. Participants will be randomized 1:1 to DTX301 or placebo and followed closely for 36-64 weeks. Between Week 36 and Week 64, eligible participants will cross over and receive DTX301 if they had previously received placebo, and some who received DTX301 may receive placebo. The planned study duration is up to 324 weeks. Upon completion of this study or early withdrawal, all participants who received DTX301 are invited to enroll in the Disease Monitoring Program (DMP) for follow-up for up to an additional 5 years.

Conditions

• OTC Deficiency

Interventions

Type	Name	Description
GENETIC	DTX301	non-replicating, self-complementary recombinant adeno-associated virus serotype 8 (AAV8) vector
OTHER	Placebo	normal saline infusion
DRUG	Oral Corticosteroids	Participants who receive DTX301 solution will receive oral corticosteroids.
DRUG	Placebo for oral corticosteroids	Participants who receive Placebo will receive placebo corticosteroids to maintain the study blind
DRUG	Sodium Acetate	A tracer for the Ureagenesis Rate Test (URT)

Timeline

• Start date: 2022-10-18
• Primary completion: 2027-09-01
• Completion: 2031-03-01
• First posted: 2022-04-25
• Last updated: 2026-02-17

Locations

16 sites across 10 countries: United States, Argentina, Brazil, Canada, France, Germany, Japan, Netherlands, Portugal, Spain

Regulatory

• FDA-regulated drug study