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Long‑Term Safety Follow‑up of Ornithine Transcarbamylase Deficiency Patients Treated with ECUR‑506D and ECUR‑506A

Verified siteInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

A rare inherited condition called Ornithine Transcarbamylase Deficiency causes the body to be unable to process ammonia, a waste product that can build up to dangerous levels. The study evaluates two experimental gene‑therapy products, identified as ECUR-506D and ECUR-506A. Both use a harmless adeno-associated virus as a delivery vehicle to carry a correct copy of a missing gene into the liver cells; one delivers the normal OTC gene, while the other carries a tool that edits the PCSK9 gene to reduce harmful protein production. Gene therapy is a type of treatment that adds or repairs genetic material to help the body work properly.

The purpose of the study is to assess the long‑term safety of the investigational product in people who have received it and in those who have not. Participants are followed for many years with regular visits that include physical measurements, blood and urine tests, heart rhythm checks, and neurological examinations. Any serious health events, such as episodes of high ammonia called hyperammonemic crises, are recorded, and information about growth, liver function, and overall health is collected to monitor how participants fare over time.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Enrollment and baseline assessment

    After joining the study, a complete baseline evaluation is performed. this includes a physical exam, measurement of height and weight, vital sign check, neurologic exam, 12‑lead ecg, and collection of blood and urine samples for safety laboratory tests such as blood count, chemistry, liver function, coagulation, serum pcsk9, and urinalysis.

    The baseline also records any previous hyperammonemic crises, current medication use, and dietary protein allowance.

  2. Step 2

    Administration of investigational product

    Participants who are assigned to receive the study drug undergo a single intravenous infusion of either ecur-506d or ecur-506a.

    The infusion is delivered through a vein over a period determined by the clinical team; the protocol does not specify an exact dose amount or unit.

    The infusion is performed in a clinical setting where immediate monitoring of vital signs and observation for any acute reactions are carried out.

  3. Step 3

    Immediate post‑infusion monitoring

    Following the infusion, the participant remains under observation for a defined period, typically several hours, during which vital signs, neurologic status, and any adverse symptoms are recorded.

    Additional blood samples may be taken to assess vector pharmacokinetics (pk) in the blood and to check for shedding of the viral vector in plasma, saliva, urine, and feces.

  4. Step 4

    Scheduled long‑term follow‑up visits

    The participant attends regular follow‑up visits for up to fifteen years, as the study runs from may 2026 to june 2041.

    At each visit, a physical exam, neurologic exam, and 12‑lead ecg are repeated. vital signs, height, weight, and body surface area are measured.

    Blood and urine are collected for safety tests, including liver function, serum pcsk9, ammonia, citrulline, glutamine, blood urea nitrogen, and antibody response to the viral vector.

    The schedule may include visits every six months or as defined by the study protocol.

  5. Step 5

    Assessment of hyperammonemic crises and related outcomes

    If a hyperammonemic crisis occurs, the participant or caregiver records the event, including daily ammonia levels, duration of hospitalization, need for intensive care, and any required treatments such as oral scavenger medication, intravenous scavenger therapy, or hemodialysis.

    The severity of each crisis (mild, moderate, severe) is documented according to the protocol definitions.

  6. Step 6

    Developmental and functional evaluations

    Age‑appropriate developmental assessments are performed using standardized tools such as the bayley scale of infant development iv or the kaufman assessment battery for children.

    These evaluations are scheduled at intervals specified by the study to monitor neurodevelopment over time.

  7. Step 7

    Final study closure

    The study concludes when the participant reaches the end of the follow‑up period or withdraws consent.

    A final comprehensive assessment, including all safety examinations, laboratory tests, and documentation of any serious adverse events, is completed.

    The collected data are used to evaluate the long‑term safety of the investigational product.

Who can join the trial?

5 criteria

  • Must have already taken part in the earlier study called iECURE parent protocol and either finished it or stopped participating in it.
  • Must be a male (boy) who has the condition being studied.
  • Must be at least 2 years old.
  • Because the participant is a child, a parent or legal guardian (called a legal authorized representative (LAR)) must be able and willing to follow all study rules.
  • The parent or legal guardian must give written consent (permission) for the child to join the study, and the child must also agree (called assent) if they are old enough to understand.

Who cannot join the trial?

1 criterion

  • None
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Investigated drugs

  • ECUR-506D

    is an investigational gene‑therapy product given by a short IV infusion. It uses a harmless virus (adeno‑associated virus type rh79) that carries a normal copy of the human OTC gene. The goal is to deliver this gene into the patient’s cells so that they can produce the missing OTC protein, which may help treat conditions caused by OTC deficiency.

  • ECUR-506A

    is another investigational gene‑therapy product administered as an IV infusion. It also uses a harmless adeno‑associated virus (type rh79), but this virus carries a special enzyme called a meganuclease that can cut and edit the PCSK9 gene inside the body’s cells. By editing PCSK9, the therapy aims to lower the amount of this protein, which can influence cholesterol levels and related health conditions.

What is already known about the treatment

  • ECUR-506D

    This investigational product is given by a one‑time intravenous infusion that delivers a harmless virus carrying a healthy copy of the human OTC gene to liver cells. It is still in clinical testing and has orphan‑drug status, meaning it is not yet approved for general medical use. The therapy is aimed at treating Ornithine Transcarbamylase (OTC) deficiency, a rare inherited disorder that impairs the body’s ability to remove ammonia. It works by using the viral vector to add a functional OTC gene, allowing the liver to produce the missing enzyme and restore normal metabolism.

  • ECUR-506A

    This experimental drug is also administered as an intravenous infusion, using a harmless virus that carries a tiny DNA‑cutting tool (meganuclease) designed to edit the PCSK9 gene in liver cells. It is currently in the research stage and holds orphan‑drug designation, so it is not yet approved for routine treatment. The main goal is to lower blood cholesterol by disabling the PCSK9 gene, which normally reduces the removal of “bad” cholesterol from the bloodstream. The virus delivers the editing tool to the liver, where it precisely cuts the PCSK9 gene, leading to a lasting reduction in cholesterol levels.

Investigated diseases

Ornithine Transcarbamylase Deficiency (OTC) - Ornithine transcarbamylase deficiency (OTC) is a hereditary disorder that affects the enzyme responsible for converting waste nitrogen into urea in the liver. Because the enzyme does not work properly, ammonia builds up in the blood. The condition can appear in newborns or develop later in childhood or adulthood, often after a high‑protein meal or illness. Elevated ammonia may cause symptoms such as irritability, confusion, or changes in behavior, which can come and go. Over time, repeated episodes can lead to a pattern of intermittent neurological changes and growth concerns.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase I/IITrial ID2024-514190-21-00Protocol codeECUR-LTFUEstimated enrolment13 patientsSponsorIecure Inc.

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