Gene therapy as a potential treatment for vision loss explores the use of genes to replace or repair damaged cells in the eye, aiming to restore visual function.
The world of gene therapies for vision loss is experiencing a significant leap forward, with several innovative companies making promising strides in both traditional gene replacement and optogenetic approaches. These advancements hold the potential to revolutionise treatments for genetic vision loss conditions such as retinitis pigmentosa, age-related macular degeneration (AMD), and other retinal degenerations.
One of the most notable developments comes from Spark Therapeutics, whose Luxturna remains a landmark therapy as the first FDA-approved gene therapy for a genetic retinal disease. Luxturna delivers a functional RPE65 gene to patients with retinitis pigmentosa (RP), offering potential curative vision restoration after just one or two injections.
Another promising candidate is ABBV-RGX-314, a single-dose investigational gene therapy developed by REGENXBIO. This therapy uses an AAV vector to deliver genes encoding anti-VEGF proteins to retinal cells, showing promise in treating wet AMD. The therapy is currently undergoing clinical trials.
Meanwhile, companies like Nanoscope Therapeutics are focusing on gene-agnostic optogenetic therapy to restore vision in patients blinded by retinal degeneration. Nanoscope's therapy targets bipolar cells to restore light sensitivity and has completed Phase 2 clinical trials, now seeking FDA approval.
Other companies advancing optogenetic therapies in clinical trials include Ray Therapeutics, GenSight, Bionic Sight, and Kiora Pharmaceuticals. Their therapies aim to confer light sensitivity to retinal ganglion cells or bipolar cells in patients with advanced RP or Usher syndrome. Early trial results show modest vision restoration.
Kiora Pharmaceuticals’ KIO-301 is a photoswitch molecule enabling retinal ganglion cells to respond to light, tested in Phase 1/2 trials in Australia, showing initial vision restoration in advanced RP patients.
The potential of CRISPR/Cas9 gene editing technology in retinal diseases is also being explored, representing a growing frontier in gene therapy.
However, designing gene therapies to address vision loss is challenging due to the limited cargo capacity of the carrier (AAV), which typically takes loads of around 5 kb. This limitation makes it unfeasible to develop one therapy for each mutation, especially for extremely rare mutations. As a result, the use of gene therapy will likely be limited to a small number of patients with specific mutations and rare diseases.
Despite these challenges, hopes that gene therapy can treat a vast group of diseases are slowly becoming a reality. Companies like SpliceBio are making significant strides. Barcelona-based SpliceBio announced a $135 million series B financing to fund the development of its lead program SB-007 for Stargardt disease.
On the regulatory front, AbbVie and Regeneron's ABBV-RGX-314 gene therapy for wet AMD is in a U.S. and global trial, with plans for regulatory approval in Europe and the U.S. later this year. Similarly, 4D Molecular Therapeutics' 4D-150 gene therapy for wet AMD is in phase 3 trials.
However, the high cost of gene therapies remains a concern. Luxturna, for instance, costs €345,000 ($394,290) per eye in Germany and about $425,000 in the U.S. To address this issue, some companies are spacing out the payment for gene therapies over time and conditioning the payment to the therapy working.
In conclusion, the latest advancements in gene therapies for genetic vision loss highlight promising progress by several innovative companies. These therapies bring hope for more effective and potentially curative treatments for genetic vision loss conditions. However, challenges remain, including the high cost and limited cargo capacity of gene therapies, which may limit their accessibility to a larger number of patients.
- The biotech industry, with companies like Spark Therapeutics, REGENXBIO, Nanoscope Therapeutics, Ray Therapeutics, GenSight, Bionic Sight, Kiora Pharmaceuticals, and SpliceBio, are pushing the boundaries of gene therapy to treat rare diseases like retinitis pigmentosa and Usher syndrome, with promising results in clinical trials.
- In the realm of science and medical-conditions, gene therapies are being developed to address vision loss, such as Luxturna for retinitis pigmentosa and ABBV-RGX-314 for wet AMD, which use advanced techniques like CRISPR/Cas9 gene editing.
- Despite the significant progress in gene therapy, the high cost and limited cargo capacity of gene therapies may pose challenges for their accessibility to a larger number of patients in the health-and-wellness sector, necessitating creative solutions like spacing out payments and making them conditional on success.
