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A study to optimize the delivery of AAV2-GDNF and gadoteridol into the brain for patients with Parkinson's disease

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What is this trial about?

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

This study focuses on Parkinson's Disease, a condition that affects the nervous system and impacts movement. The research aims to investigate the use of a specific method to deliver a gene therapy called AB-1005 directly into a part of the brain known as the putamen. The therapy AB-1005 is a form of AAV2-GDNF, which uses a modified virus to deliver a protein intended to support nerve cells. During the procedure, a substance called gadoteridol may be used as a contrast agent to help with imaging.

The study is conducted in two stages to refine how the medication is delivered. In the first stage, doctors use an MRI, which is a medical imaging technique that uses strong magnets to create detailed pictures of the body, to monitor the delivery in real time. This helps ensure the treatment reaches the correct area. In the second stage, the process is tested using a different surgical setup to see if the delivery can be successful without constant imaging monitoring. The goal is to find the most effective and consistent way to administer the treatment into the brain.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    <b>stage 1</b>: infusion with brain imaging

    An injection of the test product, known as aav2-gdnf (a solution containing a viral vector designed to deliver a specific protein to the brain), is performed directly into the putamen, which is a specific part of the brain. this is done using a prescriptive infusion algorithm, which is a specialized method to control how the liquid is delivered.

    During this process, intraoperative mri (a real-time magnetic resonance imaging scan used during surgery) is used to monitor the delivery of the medication to ensure it reaches the intended area.

    A background medication called prohance (a contrast agent used to make images clearer during scans) is also administered through an injection into the putamen at a dose of 8 micromoles.

  2. Step 2

    <b>stage 2</b>: infusion without real-time brain imaging

    The test product, aav2-gdnf, is injected into the putamen using the same prescriptive infusion algorithm.

    Unlike the first stage, this stage does not use real-time mri monitoring during the procedure. instead, the injection is performed using a standard stereotactic platform, which is a specialized surgical tool used to guide instruments to precise locations in the brain.

    The background medication, prohance, is administered at a dose of 8 micromoles.

  3. Step 3

    <b>follow-up assessments</b>

    Various clinical evaluations are conducted to monitor health and safety. these include neurological and physical examinations, checks of vital signs (such as heart rate and blood pressure), and clinical laboratory measures (blood tests).

    cognitive and emotional tests, such as the moca score (a test for mental sharpness), the bdi-ii score (a tool to check for symptoms of depression), and the c-ssrs (a tool to assess mood and safety), are performed.

    neuroimaging (brain scans) and tests to check for immunological responses (how the body's immune system reacts to the aav2-gdnf) are carried out to monitor the effects of the treatment.

Who can join the trial?

9 criteria

  • You must be between 45 and 75 years old at the time you sign the agreement to join the study.
  • You must have been diagnosed with Parkinson's Disease (a condition that affects movement) for more than 10 years.
  • You must have bradykinesia, which means slow movement, along with at least one of the following: rigidity (muscle stiffness), resting tremor (shaking while at rest), or postural instability (difficulty with balance).
  • Your disease must be at stage III or IV on the Hoehn and Yahr scale (a system used to measure the progression of Parkinson's) while you are in an OFF state, which means your medication is not currently working to control your symptoms.
  • Your score on the MDS-UPDRS Part III (a test used by doctors to measure motor skills and movement) must be greater than 40 while you are in an OFF state.
  • You must have been taking a stable amount of your Parkinson's medication for 4 weeks or less.
  • Your symptoms must show at least a 30% improvement on the MDS-UPDRS Part III test after taking levodopa (a common medication used to treat Parkinson's).
  • You must agree to follow standard contraceptive requirements, which are rules to prevent pregnancy during the study.
  • You must sign the informed consent, which is a formal document where you agree to participate in both the main study and the long-term follow-up period.

Who cannot join the trial?

12 criteria

  • Signs of secondary or atypical parkinsonism, which means having symptoms that look like Parkinson's disease but are actually caused by a different underlying medical condition or a different type of movement disorder.
  • Long-term use of immunosuppressive therapy, which refers to medications that weaken the body's immune system to prevent it from attacking itself or rejecting a transplant.
  • Having previously received cell or gene therapy, which are treatments that involve adding, removing, or changing genetic material or using living cells to treat a disease.
  • Having abnormal laboratory values, which means blood tests or other medical tests show results that are outside of the healthy or expected range.
  • Having a current or past history of psychosis, a mental state where a person loses touch with reality, or an impulse control disorder, which is a difficulty controlling sudden urges or behaviors.
  • Having depression that is not being treated or is not being managed well enough, specifically measured by a score of 20 or higher on the Beck Depression Inventory (a standard questionnaire used to measure the severity of depression).
  • Having suicidal ideation, which refers to thoughts of self-harm or suicide, as identified by specific questions on the Columbia-Suicide Severity Rating Scale.
  • Having cognitive impairment that is significant enough to affect daily life, measured by a score lower than 25 on the Montreal Cognitive Assessment (a tool used to check memory, attention, and thinking skills).
  • Having a current or past history of malignancy, which is a medical term for cancer, though skin cancers like cutaneous squamous or basal cell carcinomas are allowed.
  • Having any medical reason why you cannot undergo an MRI (a type of medical imaging), surgery, or anesthesia (medication used to prevent pain during surgery), especially while lying face down.
  • The use of PD pump therapies, such as intestinal gel or subcutaneous apomorphine, which are devices or medications used to deliver constant doses of medicine for Parkinson's disease.
  • Having a history of brain surgery, including deep brain stimulation (DBS), which is a procedure where wires are placed in the brain to help control movement symptoms.
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Investigated drugs

AAV2-GDNF is an experimental gene therapy delivered through an injection into a specific part of the brain. It uses a modified, harmless virus to carry instructions into brain cells, teaching them to produce a specific protein that helps support and protect nerve cells.

What is already known about the treatment

  • AAV2-GDNF

    This experimental gene therapy is administered as a solution through a direct injection into a specific part of the brain called the putamen. Currently being studied in clinical trials, it is designed to help treat Parkinson's disease by using a modified, harmless virus to deliver instructions to brain cells. Once inside, the virus encourages the body to produce a specific protein that helps protect and support the survival of nerve cells. It is classified as a gene therapy product.

  • Gadoteridol

    This medication is an injection used during medical imaging to make certain structures in the body show up more clearly on an MRI scan. It works by acting as a contrast agent that alters the magnetic properties of water molecules in the body, which helps doctors see detailed images of internal organs and tissues. It is a widely used, approved substance in medical practice and belongs to a class of drugs known as gadolinium-based contrast agents.

Investigated diseases

Parkinson's disease - This is a progressive condition that affects the nervous system. It occurs when certain nerve cells in the brain gradually stop working properly. As the condition advances, it typically leads to changes in movement and physical control. The loss of these cells affects the brain's ability to send signals to the muscles. The symptoms generally worsen over time as the underlying changes in the brain continue.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-522441-21-00Protocol codeASK-PD5-CS202Estimated enrolment30 patientsSponsorAskbio Inc.

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).