🚀 UAE's Pioneering Leap into Gene Therapy for Inherited Blindness

In a landmark achievement for medical innovation, the United Arab Emirates has launched its first-ever gene therapy clinical trial targeting MerTK-related retinitis pigmentosa (RP), a rare form of inherited retinal dystrophy that leads to progressive vision loss. Funded by Abu Dhabi's Department of Health (DoH) through its Healthcare Research and Innovation Fund, the trial represents a bold step toward precision medicine in the region. This initiative not only addresses an unmet need for patients with this devastating condition but also positions Abu Dhabi as a global hub for advanced therapies.

The trial, led by U.S.-based biopharmaceutical company Opus Genetics, will evaluate OPGx-MERTK, an investigational adeno-associated virus (AAV)-based therapy designed to deliver a functional copy of the mutated MERTK gene directly to retinal cells. Conducted at Cleveland Clinic Abu Dhabi in collaboration with DoH, the Innovative Research Oversight and Support (IROS) division of M42, and the Authority of Social Contribution – Ma’an, clinical activities are set to commence in 2026. For the thousands affected worldwide, including those in the Middle East where inherited retinal diseases (IRDs) impact up to 5% of the population, this trial offers a glimmer of hope where none existed before.

MerTK-related RP stems from biallelic mutations in the MERTK gene, which encodes a receptor tyrosine kinase crucial for phagocytosis—the process by which retinal pigment epithelial (RPE) cells clear shed outer segments from photoreceptors. Without functional MerTK, debris accumulates, triggering photoreceptor degeneration, night blindness, tunnel vision, and eventual blindness, often starting in childhood or early adulthood. Affecting approximately 1-2% of all RP cases (with RP prevalence around 1 in 4,000 globally), MERTK-RP impacts an estimated 60,000 people worldwide.

Retinitis Pigmentosa: The Genetic Puzzle Behind Progressive Blindness

Retinitis pigmentosa encompasses over 80 genetic subtypes, making it a heterogeneous group of IRDs characterized by initial rod photoreceptor death followed by cone involvement. Symptoms typically begin with nyctalopia (night blindness), progress to mid-peripheral scotomas (blind spots), and culminate in central vision loss. Bone spicule pigmentation in the fundus, waxy pallor of the optic disc, and attenuated retinal vessels are hallmark signs on examination.

Globally, RP affects about 1.5 million individuals, with higher rates in consanguineous populations common in the Arab world, including the UAE. In the MENA region, genetic studies show MERTK mutations as a leading cause in some Arab cohorts, underscoring the trial's regional relevance. Diagnosis involves electroretinography (ERG) showing reduced responses, optical coherence tomography (OCT) revealing thinning outer retina, and genetic testing via next-generation sequencing (NGS) panels.

• Nyctalopia: Difficulty seeing in low light, often first symptom by age 10-20.
• Peripheral vision loss: Tunnel vision effect, increasing fall risk.
• Central vision impairment: Reading and face recognition challenges in later stages.
• Photopsia: Flashing lights from retinal stress.

Currently, management is supportive—vitamin A supplementation, low-vision aids, and lifestyle adaptations—but no therapies halt progression until now.

Unraveling MERTK's Role: From Phagocytosis Failure to Retinal Ruin

The MERTK gene on chromosome 2q13 encodes proto-oncogene tyrosine-protein kinase MER, a TAM receptor family member (Tyro3, Axl, MerTK). In the retina, MerTK facilitates RPE-mediated phagocytosis of photoreceptor outer segments (POS), a daily renewal process essential for vision maintenance. Mutations disrupt this, causing POS accumulation, microglial activation, and apoptotic photoreceptor death.

Over 100 pathogenic variants reported, including missense, frameshift, and large deletions. In RCS rat model (MerTK null), preclinical studies show AAV-MerTK restores phagocytosis and preserves electrophysiology. Human iPSC-derived RPE models confirm similar defects, validating gene augmentation as a strategy.

In the UAE, consanguinity elevates autosomal recessive RP risk, with MERTK prominent in Arab pedigrees (up to 18% in North Africa). Early genetic screening via UAE's genomic programs could identify candidates.

The Mechanics of OPGx-MERTK: AAV Delivery and Subretinal Precision

OPGx-MERTK uses AAV2/8 capsid optimized for RPE tropism, carrying human MERTK cDNA under RPE-specific promoter. Subretinal injection—via pars plana vitrectomy—creates a bleb under the macula, maximizing transduction. Preclinical mouse models demonstrate sustained MerTK expression, POS clearance restoration, and ONL preservation up to 6 months.

Step-by-step process:

• Patient selection: Confirmed biallelic MERTK mutations, preserved photoreceptors on OCT.
• Vitrectomy: Core removal, membrane peeling if needed.
• Injection: 150-300µL vector (dose-escalation).
• Follow-up: Safety monitoring, multimodal imaging (FAF, mfERG), visual function (BCVA, FW100).

Photo by Annie Spratt on Unsplash

Trial Blueprint: Phase 1/2 Design and Endpoints

This open-label, ascending-dose study enrolls adults with advanced MERTK-RP. Primary endpoints: safety (ocular/systemic AEs, inflammation via grading), tolerability. Secondary: efficacy via best-corrected visual acuity (BCVA), full-field stimulus threshold (FST), mobility testing. Exploratory: OCT thickness, fundus autofluorescence (FAF) stability.

Inspired by Luxturna (RPE65; FDA-approved 2017), which improved multi-luminance mobility testing (MLMT) in 9/20 Phase 3 patients, endpoints emphasize functional gains. Dosing starts low, escalates based on Data Safety Monitoring Board (DSMB) reviews. Duration: 52 weeks core, long-term extension.

Strategic Partners Driving Innovation in Abu Dhabi

Opus Genetics, spun from Foundation Fighting Blindness, specializes in IRD gene therapies (pipeline: 7 AAV programs). DoH's fund prioritizes cell/gene therapies, awarding AED19M+ previously. Cleveland Clinic Abu Dhabi has precedent: RPE65 gene therapy restored vision in two Emirati sisters. M42's IROS streamlines oversight; Ma’an ensures community access.

Quotes underscore commitment: DoH Undersecretary Dr. Noura Al Ghaithi: “Abu Dhabi is demonstrating leadership in precision medicine.” Opus CEO George Magrath: “First real opportunity to change disease course.”

Abu Dhabi's Healthcare Ecosystem: A Magnet for Advanced Therapies

DoH's 2026 fund targets gene therapy, precision oncology, neurodegeneration—receiving 150+ proposals last cycle. UAE administered first SMA gene therapy (ITVISMA) in 2025, DMD therapies earlier. Future Health Summit 2026 theme: “To Sense is to Predict”—aligning with genomic foresight. Investments position UAE for 10% global clinical trials share by 2030.

Regional IRD burden: Consanguinity boosts recessive forms; UAE genomic programs identify MERTK hotspots.

Challenges, Risks, and Ethical Considerations

Gene therapy hurdles: Immunogenicity (pre-existing AAV antibodies exclude ~30-50%), surgical risks (retinal detachment <5%), off-target effects. Long-term: Insertional mutagenesis rare with AAV. Ethics: Equitable access in low-resource settings, informed consent for rare diseases.

• Vector capacity: MERTK (6.7kb) fits AAV (~4.7kb payload).
• Patient screening: NGS mandatory.
• Regulatory: UAE's rapid MoHAP approvals accelerate.

Luxturna durability: 4+ years vision gains, but inflammation managed with steroids.

Photo by Олександр К on Unsplash

Global Ripple Effects and Future Horizons

If successful, OPGx-MERTK could join Luxturna, bota-cel for other RP. UAE's model—public-private funding, international expertise—attracts trials. Broader: CRISPR editing, optogenetics next. By 2030, 10+ IRD therapies projected.

Patients: Contact Cleveland Clinic Abu Dhabi or Foundation Fighting Blindness for eligibility. This trial symbolizes hope, innovation, and UAE's healthcare ascent.