Genetically inherited diseases are always challenging to diagnose, treat, and cure. One such rare yet, complex condition of the eye is Retinitis Pigmentosa (RP). People with RP have minimal treatment options and lose vision entirely over time.
Thanks to advances in gene therapy, such individuals may have hopes on the horizon. RP clinical trials aimed at finding a standard treatment option for the condition, thereby improving the quality of life for the patients.
This article helps identify such promising Retinitis Pigmentosa treatment trials of 2022 and discusses their potential results.
Did You Know?
You may carry genes associated with inherited conditions and not develop the condition but may pass it to your children. Learn more:
What Is Retinitis Pigmentosa?
RP is a genetic condition affecting the retina, causing loss of night vision and vision over time. The signs usually start from childhood, and this condition can affect the quality of life.
The fact that no standard treatment processes are in place makes this a topic of interest for researchers globally.
This article will take you through the existing and proposed Retinitis Pigmentosa treatment in 2022 and shed light on current research advances.
Overview of Retinitis Pigmentosa
RP is a group of conditions that affect the retina of the eyes and is passed genetically.
Approximately 1 in 4000 Americans develop RP in their lifetimes. RP is primarily bilateral (affecting both eyes). However, in rare cases, the condition can be unilateral (involving a single eye).
There are two types of RP identified.
- Non-syndromic RP - About 70-80% of all cases of RP are non-syndromic, meaning the symptoms are restricted to the eye.
- Syndromic RP - In some cases, RP can be associated with other systemic diseases (conditions affecting the entire body). One such condition is Usher Syndrome (a genetic condition causing hearing and vision loss).
RP is characterized by damage to the light-sensitive cells in the eyes called photoreceptors.
The first sign of RP is night vision loss, and this begins by the age of 10-20. Eventually, tunnel vision develops; by age 40, the person can lose eyesight completely.
About 50 different genes may lead to Retinitis Pigmentosa.
- 10-20% of these cases are autosomal dominant, meaning just one copy of the altered or mutant gene is enough to cause the condition.
- 20% of these cases are autosomal recessive, meaning two copies of the altered or mutant genes are needed to cause the condition.
- About 10% of the cases are X-linked recessive inherited, meaning they are caused by changes in the genes located on the X chromosome.
- The remaining cases are termed sporadic, and they don’t have a family history associated with them.
Retinitis Pigmentosa Treatment: 2022 Research Advances
Multiple clinical trials explored Retinitis Pigmentosa treatment options in 2022. Many of these trials are still in progress, trying to find a standard treatment for the condition.
The following are some of the popular research advances to be aware of.
FDA Approves SparingVision’s-Restoring Gene Therapy
Prodygy Phase 1/2 Clinical Trial
SparingVision is a genomics company based out of Paris, France.
At the end of 2022, the brand announced that the Food and Drug Administration (FDA) had approved its application for a new therapy using SPVN06 to help treat RP.
Since the approval is in place, the company can initiate the Promising Rod-Cone Dystrophy Gene Therapy (PRODYGY), a first-in-human clinical trial (phase I/II) for RP.
What is the PRODYGY trial?
The Prodygy study was one of the significant RP news in 2022.
This trial will analyze the safety, efficacy, and treatment progress of the SPVN06 injection in RP patients with a mutation of the RHO, PDE6A, or PDE6B genes.
The trial plans to recruit 33 patients with RP for the study. After 12 months, the patients will go through a follow-up study, analyzing the safety and tolerability of the injection.
The study also plans to perform a long-term follow-up after five years to check the drug's quality of life and safety.
Optogenetic Therapies for Advanced RP
Optogenetics involves adding light-sensing molecules called opsins to the retina to the retina's photoreceptor cells to improve vision.
Optogenetic therapy was one of the most explored treatment options for RP in 2022.
In 2021, Nanoscope Therapeutics Inc., a biotechnology company based out of Dallas, Texas, conducted a Phase 1/2a optogenetic clinical study to analyze the effects of Multi-Characteristic Opsin (MCO-010) on visual restoration in 11 patients with RP.
After eight weeks of treatment, all patients experienced improved vision restoration and better quality of life.
Following this success, the company announced a Phase 2b trial in 2022 that recruited 27 individuals with advanced RP and severe vision loss to analyze the effects of MCO-010 injections on their vision.
The trial results are yet to be released, and you may be able to check the RP treatment updates sometime in 2023.
Oral Antioxidant Therapy
NAC Attack is a clinical trial exploring oral N-acetylcysteine (NAC), an antioxidant, in restoring vision and treating RP.
This Phase III clinical trial is sponsored by John Hopkins University. About 438 participants will participate in the study, and the trial will be conducted in approximately 30 centers across the USA and Europe.
Phase I of this trial found a small but significant improvement in vision and light sensitivity with oral NAC for six months.
The Phase III of this trial is set to be completed in March 2028.
Other Gene Therapy Clinical Trials
Up until 2022, the only accepted treatment for RP one is Luxturna.
This is a gene therapy solution for people with the RPE65 gene mutation.
There are no accepted treatment options for other RPs with different gene mutations.
Since multiple genes are associated with RP, finding gene therapies for each one of these mutations is going to be an expensive and time-consuming affair, which, however, must be done.
Some of the other clinical trials currently in progress for RP include the following.
- A controlled study was conducted to analyze the effects of Ultevursen in people with RP caused by mutations in the Exon 13 of the USH2A Gene. This trial may be completed by the end of 2024.
- A five-year project analyzes the progression rate of RP in people with the EYS gene mutation. The Foundation Fighting Blindness funds this project, which is expected to be completed in 2025.
- This is another project funded by the Foundation Fighting Blindness that will analyze the disease progression and natural history of PCDH15-Related Retinal Degeneration in people with Usher Syndrome. The results of the project will help accelerate RP treatments.
How Much Does Retinitis Pigmentosa Gene Therapy Cost?
Right now, the only approved gene therapy treatment for RP is Luxturna. This is developed and marketed by Spark Therapeutics.
This one-time treatment will cost $425,000 for one eye or $850,000 for both eyes.
Is There A Cure Coming Soon For Retinitis Pigmentosa?
How soon will there be a cure for RP? This is a question in everyone’s mind.
Multiple clinical trials have been conducted to help understand the condition better and explore standard and safe treatment solutions.
So, there is definitely hope on the horizon for people with RP. As these clinical trials progress further, researchers may be able to find a standard treatment option for RPs caused by different gene mutations.
Certain genetic tests may help confirm the presence of Inherited Retinal Diseases (IRDs).
These tests can help you know if you are a carrier of specific gene mutations that may cause RP and other IRDs and take proactive steps.
Summary: Retinitis Pigmentosa Treatment In 2022
- Retinitis Pigmentosa (RP) is a genetic condition that leads to vision loss over time. Right now, there are no specific treatments to cure the condition.
- The first signs of RP are loss of night vision and tunnel vision, which develop between the ages of 10 and 20. When left untreated, the person can lose sight by 40.
- FDA-accepted Retinitis Pigmentosa treatment until 2022 was restricted to just Luxturna. This gene therapy worked on RP caused by the RPE65 gene mutation.
- In the last couple of years, several clinical trials have intended to find standard treatment options for RP caused by different gene mutations. These trials may help find the right RP over time.
- The PRODIGY Phase I/II is a clinical trial by SpringsVision to use SPVN06 therapy for treating RP. This FDA-approved trial will analyze the efficacy, safety, and long-term quality of life of the SPVN06 gene therapy drug.
- Apart from PRODIGY, other clinical trials now target RPs caused by specific gene mutations. The results of these trials may help create a standard treatment plan for the condition.
References
- https://www.ncbi.nlm.nih.gov/books/NBK519518/#
- https://www.aao.org/eye-health/diseases/what-is-retinitis-pigmentosa
- https://pubmed.ncbi.nlm.nih.gov/36071725/
- https://clinicaltrials.ucsf.edu/retinitis-pigmentosa
- https://www.sciencedaily.com/releases/2022/06/220617101834.htm
- https://www.cnbc.com/2018/01/03/spark-therapeutics-luxturna-gene-therapy-will-cost-about-850000.html
