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Adeno-Associated Virus Vector Containing The Human Rpgr Gene

A groundbreaking clinical trial is underway to assess the safety and effectiveness of AGTC-501, an innovative gene therapy for X-linked Retinitis Pigmentosa (XLRP). This study aims to evaluate the potential of a single subretinal injection of AGTC-501 in improving visual function for male participants with XLRP caused by mutations in the RPGR gene. The trial compares two doses of the therapy against an untreated control group, offering hope for those affected by this rare genetic eye disorder.

Table of Contents

What is AGTC-501?

AGTC-501, also known by its scientific name laruparetigene zovaparvovec or rAAV2tYF-GRK1-RPGR, is an innovative gene therapy designed to treat a specific type of inherited eye disease[1]. This therapy is currently being studied in clinical trials to evaluate its safety and effectiveness in treating X-linked retinitis pigmentosa (XLRP), a rare genetic condition that causes progressive vision loss, primarily affecting males[1].

How Does AGTC-501 Work?

AGTC-501 is a gene therapy that uses a modified virus to deliver a healthy copy of the RPGR gene to the retina. Here’s a simplified explanation of how it works:

  1. The therapy is made using a harmless virus called adeno-associated virus (AAV).
  2. This virus is modified to carry a healthy copy of the RPGR gene, which is faulty in people with XLRP.
  3. The modified virus is injected directly under the retina in a procedure called a subretinal injection.
  4. Once in the eye, the virus delivers the healthy RPGR gene to the retinal cells.
  5. These cells can then use the healthy gene to produce the correct protein, potentially slowing or stopping vision loss[1].

Target Condition: X-Linked Retinitis Pigmentosa

X-linked retinitis pigmentosa (XLRP) is a genetic eye disorder that causes progressive vision loss. It primarily affects males because the faulty gene is located on the X chromosome. Symptoms typically begin in childhood and include:

  • Night blindness (difficulty seeing in low light)
  • Loss of peripheral (side) vision
  • Eventual loss of central vision

Currently, there is no cure for XLRP, which is why gene therapies like AGTC-501 are being developed and studied[1].

Clinical Trial Details

AGTC-501 is being evaluated in a Phase III clinical trial. This is an advanced stage of research that aims to confirm the therapy’s effectiveness and safety in a larger group of patients. Key details of the trial include:

  • It’s a randomized, controlled, and masked study, meaning participants are randomly assigned to receive either the treatment or no treatment, and neither the participants nor some of the researchers know who is in which group.
  • The study is testing two different doses of AGTC-501.
  • The main goal is to see if AGTC-501 can improve vision as measured by a special test called MAIA microperimetry, which assesses retinal sensitivity[1].

Eligibility Criteria

The clinical trial has specific criteria for who can participate. Some key eligibility requirements include:

  • Male participants aged 12 to 50 years
  • Confirmed diagnosis of XLRP with a documented mutation in the RPGR gene
  • Specific levels of visual acuity and retinal sensitivity
  • No previous gene therapy treatments
  • No other significant eye conditions that could interfere with the study[1]

Potential Benefits

If successful, AGTC-501 could potentially:

  • Slow or stop the progression of vision loss in people with XLRP
  • Improve retinal sensitivity and visual function
  • Enhance the ability to see in low light conditions
  • Improve overall quality of life for individuals with this condition[1]

Safety Considerations

As with any medical treatment, there are potential risks and side effects to consider. The clinical trial is closely monitoring participants for any adverse events related to the treatment. Some potential risks may include:

  • Reactions to the surgical procedure used to administer the therapy
  • Immune system responses to the viral vector
  • Potential side effects from medications used during and after the procedure

It’s important to note that the safety of AGTC-501 is still being evaluated in the clinical trial[1].

Aspect Details
Study Type Phase III, randomized, controlled, masked, multi-center
Intervention AGTC-501 (adeno-associated virus vector containing human RPGR gene)
Target Population Males aged 12-50 with X-linked Retinitis Pigmentosa due to RPGR mutations
Primary Outcome Change in retinal sensitivity at 12 months (measured by microperimetry)
Key Secondary Outcomes Mobility test scores, visual acuity, full-field stimulus threshold, quality of life
Treatment Administration Single subretinal injection
Follow-up Duration At least 24 months
Safety Monitoring Ocular and non-ocular adverse events

FAQ

  • What is AGTC-501 and how does it work? AGTC-501 is a gene therapy product that uses a modified virus (adeno-associated virus) to deliver a healthy copy of the RPGR gene to the retina. It aims to correct the genetic defect causing X-linked Retinitis Pigmentosa, potentially improving vision in affected individuals.
  • Who is eligible for this clinical trial? The trial is open to males aged 12-50 with a confirmed diagnosis of X-linked Retinitis Pigmentosa caused by RPGR gene mutations. Participants must meet specific visual acuity criteria and have detectable retinal sensitivity and structure.
  • How is the treatment administered? AGTC-501 is administered as a single subretinal injection. This means the treatment is delivered directly beneath the retina in a surgical procedure.
  • What are the main outcomes being measured in this trial? The primary outcome is the change in retinal sensitivity measured by microperimetry at 12 months. Secondary outcomes include changes in mobility, visual acuity, and other measures of visual function and quality of life.
  • How long will participants be followed in this study? Participants will be followed for at least 24 months after treatment to assess long-term safety and efficacy of AGTC-501.

Ongoing Clinical Trials on Adeno-Associated Virus Vector Containing The Human Rpgr Gene

  • Study on the Safety and Effectiveness of AGTC-501 for Men with X-linked Retinitis Pigmentosa

    Not yet recruiting

    1 1 1 1
    Investigated diseases:
    Investigated drugs:
    Spain

Glossary

  • X-linked Retinitis Pigmentosa (XLRP): A rare genetic eye disorder that causes progressive vision loss, primarily affecting males due to mutations on the X chromosome.
  • RPGR gene: The Retinitis Pigmentosa GTPase Regulator gene, which when mutated, causes X-linked Retinitis Pigmentosa.
  • Subretinal injection: A surgical procedure where medication is delivered directly beneath the retina, the light-sensitive tissue at the back of the eye.
  • Microperimetry: A technique used to measure retinal sensitivity and assess visual function in specific areas of the retina.
  • Adeno-associated virus (AAV): A small virus used in gene therapy to deliver genetic material to cells, chosen for its safety profile and ability to infect various cell types.
  • Gene therapy: A technique that uses genes to treat or prevent disease, often by replacing a faulty gene with a functional one.
  • Visual acuity: A measure of the sharpness or clarity of vision, often tested using an eye chart.
  • Ellipsoid zone (EZ): A layer in the retina visible on optical coherence tomography (OCT) scans, used as a marker of photoreceptor health.
  • Optical coherence tomography (OCT): An imaging technique that uses light waves to take cross-section pictures of the retina.

References

  1. http://clinicaltrials.eu/trial/study-on-the-safety-and-effectiveness-of-agtc-501-for-men-with-x-linked-retinitis-pigmentosa/