What is the mechanism of action of this treatment?

Gene therapy for Retinitis Pigmentosa, such as the AAV5-RPGR vector, involves delivering a functional copy of the RPGR gene to retinal cells using adeno-associated viral (AAV) vectors. This approach aims to restore the production of the RPGR protein, which is crucial for the normal function of photoreceptor cells in the retina. By correcting the genetic defect, gene therapy can potentially halt or slow the progression of vision loss in RP patients. This is particularly important as it addresses the root cause of the disease, offering a more targeted and long-term solution compared to other treatments that primarily manage symptoms.

What side effects are associated with this type of intervention?

Gene therapy for Retinitis Pigmentosa, such as the AAV5-RPGR vector, generally involves subretinal injections. Common side effects include surgical complications, such as retinal detachment or inflammation. Patients may also experience mild to moderate adverse events like eye pain, increased intraocular pressure, and temporary vision changes. Despite these risks, many patients show improvement in visual acuity, making gene therapy a promising treatment option.

What prior FDA approvals exist?

There are no specific FDA-approved gene therapies for Retinitis Pigmentosa mentioned in the provided context. However, the AAV5-RPGR vector trial represents a promising approach by delivering a functional RPGR gene to treat X-linked Retinitis Pigmentosa. This method is similar to other gene therapies that aim to correct genetic defects by introducing functional genes into patients' cells. Broadly, gene therapy has been explored for various genetic disorders, showing potential in clinical trials for conditions like Leber congenital amaurosis and choroideremia, which are also inherited retinal diseases.

What other types of research exist?

Promising alternatives to AAV5-RPGR vector for Retinitis Pigmentosa patients include: 1) Gene-replacement therapies similar to those used for RPE65 mutations, which have shown consistent visual function improvements. 2) Stem cell-based therapies, such as human ES cell-derived retinal progenitor cell transplantation, which have demonstrated safety and potential efficacy in retinal diseases. 3) Emerging RNA-based therapies, like antisense oligonucleotides and siRNA, which target specific genetic mutations and have shown benefits in other genetic disorders.

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Virus Therapy

Gene Therapy for Retinitis Pigmentosa

Phase 3

Waitlist Available

Led By James Bainbridge, MD

Research Sponsored by MeiraGTx UK II Ltd

Eligibility Criteria Checklist

Specific guidelines that determine who can or cannot participate in a clinical trial

Must have

3 years of age or older

Has XLRP confirmed by a retinal specialist and has a predicted disease-causing sequence variant in RPGR confirmed by an accredited laboratory

Must not have

Any investigational ocular treatment or any other ocular treatment that could confound the interpretation of the efficacy results or affect participant compliance with the visit schedule

Has undergone prior retinal surgery involving the macula, macular laser photocoagulation, external-beam radiation therapy, transpupillary thermotherapy, glaucoma filtration surgery or corneal surgery

Timeline

Screening 3 weeks

Treatment Varies

Follow Up day 1 - week 52

Awards & highlights

No Placebo-Only Group

Pivotal Trial

Summary

This trial is testing a gene therapy that uses a harmless virus to deliver a healthy gene to eye cells. It targets people with X-linked retinitis pigmentosa, aiming to help their eye cells work better and slow down vision loss. Gene therapy targeting the RPE65 gene has shown promise in treating retinal diseases, with the first FDA-approved therapy in 2017.

Who is the study for?

This trial is for males and females aged 3 or older with X-linked retinitis pigmentosa (XLRP) confirmed by a specialist. Participants must have a specific genetic variant in the RPGR gene verified by an accredited lab.

What is being tested?

The trial is testing AAV5-RPGR, a form of gene therapy designed to treat XLRP. This intervention involves using a harmless virus to deliver corrected genes into the body.

What are the potential side effects?

Potential side effects of AAV5-RPGR may include immune reactions, eye inflammation or discomfort, changes in vision, headache, and possible mild fever post-treatment.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below

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I am at least 3 years old.

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I have X-linked retinitis pigmentosa confirmed by a specialist and genetic testing.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:

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I haven't had any experimental eye treatments that could affect study results.

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I have had eye surgery or treatments that involved the central part of my retina.

Timeline

Screening ~ 3 weeks3 visits

Treatment ~ Varies

Follow Up ~ day 1 - week 52

Screening ~ 3 weeks

Treatment ~ Varies

Follow Up ~day 1 - week 52

This trial's timeline: 3 weeks for screening, Varies for treatment, and day 1 - week 52 for reporting.

Treatment Details

Study Objectives

Study objectives can provide a clearer picture of what you can expect from a treatment.

Primary study objectives

Change From Baseline to Week 52 in Vision-guided Mobility Assessment (VMA) as Measured by the Ability of the Participant to Navigate Through a VMA Maze

Secondary study objectives

Change From Baseline in Mean Retinal Sensitivity Within the Central 10 Degrees Excluding Scotoma (Mean Retinal Sensitivity Within the Central 10 Degree Excluding Scotoma in Static Perimetry [MRS10]) in Static Perimetry at Week 52

Change From Baseline in Mean Retinal Sensitivity of Worse-seeing Eye Within the Central 10 Degrees Excluding Scotoma in Static Perimetry (MRS10) at Week 52

Change From Baseline in Retinal Function as Assessed by Mean Retinal Sensitivity Within the Full Visual Field (MRS90) in Static Perimetry at Week 52

+11 more

Awards & Highlights

No Placebo-Only Group

All patients enrolled in this study will receive some form of active treatment.

Pivotal Trial

The final step before approval, pivotal trials feature drugs that have already shown basic safety & efficacy.

Trial Design

3Treatment groups

Experimental Treatment

Group I: Experimental Immediate TreatmentExperimental Treatment1 Intervention

Low dose.

Group II: Experimental - Immediate TreatmentExperimental Treatment1 Intervention

Intermediate dose.

Group III: Deferred TreatmentExperimental Treatment1 Intervention

Deferred Treatment

Treatment

First Studied

Drug Approval Stage

How many patients have taken this drug

Genetic: AAV5-hRKp.RPGR

2020

Completed Phase 3

~100

0 / 4Eligibility criteria met

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.

Mechanism Of Action

Side Effect Profile

Prior Approvals

Other Research

Gene therapy for Retinitis Pigmentosa, such as the AAV5-RPGR vector, involves delivering a functional copy of the RPGR gene to retinal cells using adeno-associated viral (AAV) vectors. This approach aims to restore the production of the RPGR protein, which is crucial for the normal function of photoreceptor cells in the retina. By correcting the genetic defect, gene therapy can potentially halt or slow the progression of vision loss in RP patients. This is particularly important as it addresses the root cause of the disease, offering a more targeted and long-term solution compared to other treatments that primarily manage symptoms.

Gene therapy for retinal and choroidal diseases.