A Phase 3 interventional study of ECUR-506 in Ornithine Transcarbamylase Deficiency, Ornithine Transcarbamylase Deficiency Disease and Ornithine Carbamoyltransferase Deficiency (Disorder), sponsored by iECURE, Inc.. Active, not recruiting at 12 sites in 4 countries. Open to male participants aged 24 Hours to 7 Months. Per ClinicalTrials.gov, last updated 2026-09-30.
Sponsored by iECURE, Inc. · Phase 3, Interventional, and Treatment
Ornithine Transcarbamylase (OTC) deficiency, the most common urea cycle disorder, is an inherited metabolic disorder caused by a genetic defect in a liver enzyme responsible for detoxifying of ammonia. Individuals with OTC deficiency can develop elevated levels of ammonia in the blood, potentially resulting in severe consequences, including cumulative and irreversible neurological damage, coma, and death. The most severe form presents shortly after birth and occurs more commonly in boys than girls.
This is a Phase 1/2/3, open-label, multicenter study evaluating the safety, efficacy, and dose of ECUR-506 in male babies with neonatal-onset OTC deficiency. The primary objective is to evaluate the safety, tolerability, and efficacy of up to three dose levels of ECUR-506 following intravenous (IV) administration of a single dose.
The study drug, ECUR-506, is an investigational gene editing therapy. Gene editing is an approach used to repair, replace, or introduce functional copies of genes that are not working properly. ECUR-506 contains a functional copy of the OTC gene, along with a gene to encode an editing enzyme that enables insertion of the OTC gene into the genome. The study drug is administered as a single IV infusion. Because genes cannot enter cells on their own, ECUR-506 uses a delivery system based on adeno-associated virus (AAV), a commonly used viral vector, to transport the genetic material into cells.
59 studies on the registry are indexed under Ornithine Carbamoyltransferase Deficiency Disease; 13 are open to participants now.
This study's planned enrollment of 20 is below the median of 30 across 28 interventional studies indexed under Ornithine Carbamoyltransferase Deficiency Disease.
Browse Ornithine Carbamoyltransferase Deficiency Disease studies →iECURE, Inc. is the lead sponsor of 2 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
Participants will receive the Low Dose of ECUR-506 delivered one time via IV Infusion.
Genetic: ECUR-506
Participants will receive an intermediate dose of ECUR-506 delivered on time via IV infusion
Genetic: ECUR-506
Participants will receive a higher dose of ECUR-506 delivered one time via IV infusion.
Genetic: ECUR-506
ECUR-506 is a gene editing treatment delivering a gene encoding the editing enzyme and an OTC gene.
Treatment-emergent adverse events (incidence, severity, seriousness, and relatedness)
Toxicity is graded in accordance with the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. Adverse events (AEs) are reported based on clinical laboratory tests, vital signs, physical examinations, Pediatric Neurologist exam parameters, electrocardiograms, and any other medically indicated assessments from the time informed consent is signed through the end of the safety follow-up period. AEs are considered to be treatment emergent (TEAE) if they occur or worsen in severity following the administration of the study treatment. TEAEs are considered treatment-related if relationship to study drug is possibly related, probably related, or definitely related.
Time frame: Over 24 weeks post infusion
Physical exam parameters
Safety- (Includes PI assessment of General Appearance, Dermatological, HEENT, Lymphatic, Respiratory, Cardiovascular, Gastrointestinal, Musculoskeletal, Neurological (Cranial Nerve Function, Motor System Function, Sensory System Function, Primitive Reflexes))
Time frame: Assessed as change from baseline at pre-specified timepoints as described in the SOE throughout the duration of the study on all enrolled and dosed participants.
Vital sign parameters
Safety- (Includes PI assessment of Systolic Blood Pressure, Diastolic Blood Pressure, Pulse Rate, Respiratory Rate, Temperature)
Time frame: Assessed as change from baseline at pre-specified timepoints as described in the SOE throughout the duration of the study on all enrolled and dosed participants.
Pediatric neurologist exam parameters
Safety- (Includes Pediatric Neurologist assessment of Neurological status by review of Cranial Nerve Function, Motor System Function, Sensory System Function, Primitive Reflexes.)
Time frame: Assessed as change from baseline at pre-specified timepoints as described in the SOE throughout the duration of the study on all enrolled and dosed participants.
Blood safety tests including hematology, serum chemistry, liver function tests, coagulation tests
Safety- (Blood Safety tests to be reviewed in relation to established normal ranges for each assessment for the applicable age group)
Time frame: as change from baseline at pre-specified timepoints as described in the SOE throughout the duration of the study on all enrolled and dosed participants.
Urinalysis evaluations
Toxicity is graded in accordance with the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE), version 5.0. Adverse events (AEs) are reported based on clinical laboratory tests, vital signs, physical examinations, electrocardiograms, and any other medically indicated assessments from the time informed consent is signed through the end of the safety follow-up period. AEs are considered to be treatment emergent (TEAE) if they occur or worsen in severity following the administration of the study treatment. TEAEs are considered treatment-related if relationship to study drug is possibly related, probably related, or definitely related.
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
12 lead ECG parameters
Safety- (Includes PI review of Heart Rate, PR Interval, RR Interval, QRS Duration, QT Interval, QTcF Interval, Overall Interpretation)
Time frame: as change from baseline at pre-specified timepoints as described in the SOE throughout the duration of the study on all enrolled and dosed participants.
Complete clinical response
Discontinuation of scavenger medication for a minimum duration of 28 days without reductions in prescribed daily protein intake during this time period by end of study.
Time frame: Over 24 weeks post infusion
Number of HAEs/person-year
Key Secondary Endpoint: Pharmacodynamics and Efficacy
Time frame: Day 1 post dose through Week 24
qPCR measurement to evaluate the clearance of both vectors in body fluids over time
Supportive Secondary Endpoint: Pharmacokinetics
Time frame: Over 24 weeks post infusion
Incidence of hyperammonemic episode (HAE)
Supportive Secondary Endpoint: Pharmacodynamics and Efficacy
Time frame: Over 24 weeks post infusion
Incidence and number of hyperammonemic episodes (HAE/HAC) resulting in hospitalization
Supportive Secondary Endpoint: Pharmacodynamics and Efficacy
Time frame: Over 24 weeks post infusion
Overall and by hospitalization severity (Mild: adjustment of dietary protein intake and oral scavenger medication / Moderate: cessation of dietary protein intake and initiation of IV scavenger therapy / Severe: requirement for hemodialysis)
Supportive Secondary Endpoint: Pharmacodynamics and Efficacy.
Time frame: Will be assessed Day 1 post dose through Wk 24 on all enrolled and dosed participants
Duration of hospitalization for each HAE/HAC
Supportive Secondary Endpoint: Pharmacodynamics and Efficacy
Time frame: Over 24 weeks post infusion
Requirement for Intensive Care Unit (ICU) care during hospitalization for each HAE/HAC
Supportive Secondary Endpoint: Pharmacodynamics and Efficacy
Time frame: Over 24 weeks post infusion
Time to liver transplant from dosing to end of study (EOS)
Supportive Secondary Endpoint: Efficacy
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Transplant free survival
Supportive Secondary Endpoint: Efficacy
Time frame: Time to lever transplant or any-cause death from dosing to EOS
Overall survival
Supportive Secondary Endpoint: Efficacy
Time frame: Time to any-cause death from dosing to EOS
Achieving and maintaining complete clinical response through end of study
Supportive Secondary Endpoint: Efficacy
Time frame: Over 24 weeks post infusion
Scavenger drug dose
Supportive Secondary Endpoint: Efficacy
Time frame: Over 24 weeks post infusion
Dietary protein intake g/kg/day
Supportive Secondary Endpoint: Efficacy
Time frame: Supportive Secondary: Over 24 weeks post infusion
Blood urea nitrogen measurements
Supportive Secondary Endpoint: Pharmacodynamics
Time frame: Over 24 weeks post infusion
Clinical Response (CR) defined as reduction in baseline standard of care therapy
Efficacy
Time frame: Assessed at Week 24
Serum Neurofilament Light Chain
Safety
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Number of participants with antibodies to AAVrh79 capsid in blood
Pharmacodynamics
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Number of participants with antibodies to hOTC transgene in blood
Pharmacodynamics
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Number of participants with antibodies to M2PCSK9 transgene in blood
Pharmacodynamics
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Incidence and time to medical management adjustments based on iECURE guidance (protein diet or scavenger medication)
Efficacy
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Fasting plasma ammonia
Pharmacodynamics
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Fasting plasma citrulline and fasting plasma glutamine levels
Pharmacodynamics
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Serum PCSK9
Pharmacodynamics
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Urinary excretion of phenylacetate metabolites
Urinary phenylacetate (mcg/mL), urinary phenylacetylglutamine (mcg/mL), urinary phenylacetate/ phenylglutamine ratio.
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Urinary excretion of orotic acid metabolites.
Urinary orotic acid (mmol/ mol creatinine), urinary uracil (mmol/mol creatinine).
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Urinary nitrogen to urinary creatinine ratio.
Urinary nitrogen to urinary creatinine ratio (mg/dL)
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Change from baseline at Week 24 post infusion in length.
Length measured in centimeters.
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Change from baseline at Week 24 post infusion in weight.
Weight measured in kilograms.
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Percent liver transduction via ISH/IF (in-situ hybridization / Immunofluorescence)"at Wk 24 collected by liver biopsy.
Pharmacodynamics
Time frame: The following will be assessed at Week 24 if liver biopsy tissue sample is sufficient.
Assess the potential on and "off" target editing by amplicon-seq in liver tissue samples of participants who received ECUR-506.
Pharmacodynamics
Time frame: The following will be assessed at week 24 if liver biopsy tissue sample is sufficient.
Assess potential off-target editing with AAV vector ITR insertion by ITR-seq in liver tissue samples of participants who received ECUR-506
Pharmacodynamics
Time frame: The following will be assessed at Week 24 if liver biopsy tissue sample is sufficient.
Assess for potential genetic changes in the liver tissue, collected by liver biopsy, through long read sequencing, in participants who have received ECUR-506
Pharmacodynamics
Time frame: The following will be assessed at Week 24 if liver biopsy tissue sample is sufficient.
With an observed genetic safety signal, genetic analysis of Whole Blood DNA may be performed on samples collected and stored at screening and week 24, in the event of an observed genomic safety signal.
Safety
Time frame: Will be assessed Day 1 post dose through Wk 24 on all enrolled and dosed participants.
Change from baseline at Week 24 post infusion in Bayley Scales of Infant and Toddler Development 4th Ed (BSID-4) for the Cognitive, Language, and Motor scales
Total Raw Scores, Growth Score Values (GSVs), and Age Equivalent Scores will be analyzed; Raw Scores range 0-162; GSVs range 428-599; Age Equivalent Scores range 1-42 months; a higher score reflects a higher level of skill.
Time frame: Assessed as change from baseline at pre-specified timepoints through Week 24 post infusion.
Quality of Life, as measured by the Pediatric QOL inventory Infant Scale (PedsQL-IS)
Quality of Life
Time frame: Will be assessed Day 1 post dose through Wk 24 on all enrolled and dosed participants.
Plan to share: No
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Ornithine Carbamoyltransferase Deficiency Disease →
iECURE, Inc.