A cancer treatment originally developed in Singapore has demonstrated remarkable effectiveness against two of the world’s most devastating eye diseases. In pre-clinical trials, PRL3-zumab reduced abnormal blood vessel leakage by 86% more than current standard treatments for wet age-related macular degeneration (AMD) and diabetic retinopathy.
This breakthrough comes at a critical time. These two conditions affect millions of people worldwide, with wet AMD alone responsible for 90% of severe vision loss cases among those diagnosed with the disease. The current treatment landscape forces patients into a grueling cycle of monthly injections directly into the eye—a procedure that carries significant risks and fails to help up to 45% of patients.
What makes this discovery particularly compelling is the delivery method. Unlike existing treatments that require dangerous eye injections, PRL3-zumab works through simple intravenous administration. This approach not only proved more effective in laboratory studies but also eliminates the risk of infection, lens damage, and other complications associated with direct eye injections.
The drug has already completed Phase II cancer trials with a favorable safety profile, providing researchers with valuable baseline data as they prepare for human trials in eye disease applications. Singapore’s Health Sciences Authority granted approval on June 16, 2025, with clinical trials expected to begin by late 2025.
The Current Treatment Trap
For decades, patients with wet AMD and diabetic retinopathy have faced a treatment reality that borders on medieval. The standard of care requires them to receive anti-VEGF injections directly into their eyeball every month, indefinitely.
Think about that for a moment. A needle, inserted through the white part of the eye, injecting medication directly into the vitreous cavity. The procedure itself takes just minutes, but the psychological toll and physical risks accumulate with each visit. Patients develop anxiety, some experience complications, and nearly half don’t even respond adequately to the treatment.
The statistics paint a sobering picture. Wet AMD affects over 200 million people globally, while diabetic retinopathy threatens the vision of anyone with diabetes—a population that continues to grow exponentially. Current treatments, while better than nothing, represent a Band-Aid approach to conditions that demand revolutionary thinking.
These diseases share a common destructive mechanism: abnormal blood vessel growth and leakage in the eye. In wet AMD, new blood vessels grow beneath the retina, leaking fluid and blood that distort central vision. Diabetic retinopathy follows a similar pattern, with high blood sugar levels damaging retinal blood vessels, leading to dangerous new vessel growth that can cause catastrophic vision loss.
The monthly injection regimen exists because current medications clear from the eye relatively quickly, requiring constant replenishment to maintain therapeutic levels. This creates a vicious cycle where patients become prisoners to their treatment schedule, living in three-to-four-week intervals between appointments.
Here’s What Nobody Tells You About Eye Disease Treatment
The medical establishment has accepted intravitreal injections as the gold standard for these conditions, but this approach fundamentally misunderstands how the eye processes medication. The assumption has always been that delivering drugs directly to the target site provides superior results with fewer systemic side effects.
This assumption is wrong.
The Singapore research reveals a counterintuitive truth: intravenous delivery actually achieves better and more sustained therapeutic levels in the eye compared to direct injection. This challenges everything ophthalmologists have believed about drug delivery to ocular tissues.
The explanation lies in the eye’s unique anatomy and blood supply. The choroidal circulation—the layer of blood vessels beneath the retina—is one of the highest blood flow rates in the human body. When PRL3-zumab enters through intravenous administration, it reaches diseased eye tissues through this robust vascular network, maintaining therapeutic concentrations longer than drugs injected directly into the vitreous cavity.
This discovery turns conventional wisdom on its head. Direct injection doesn’t necessarily mean better targeting. Instead, it may represent a fundamental misunderstanding of ocular pharmacokinetics—how drugs move through and are processed by eye tissues.
The implications extend beyond just effectiveness. Intravenous delivery eliminates injection-related complications entirely. No risk of endophthalmitis (severe intraocular infection), no trauma to delicate eye structures, no patient anxiety about needles approaching their eye. The treatment becomes as simple as receiving any other IV medication.
The PRL3 Discovery Story
The journey of PRL3-zumab from cancer laboratory to ophthalmology clinic reads like a medical detective story. In 1998, Professor Qi Zeng at Singapore’s A*STAR Institute of Molecular and Cell Biology first identified the PRL3 protein while investigating cancer metastasis mechanisms.
For over two decades, research focused exclusively on PRL3’s role in helping cancer cells spread throughout the body. The protein appeared to facilitate the cellular changes necessary for metastasis, making it an attractive target for preventing cancer progression.
The connection to eye disease emerged almost by accident. While studying PRL3’s broader biological functions, researchers noticed its unexpected upregulation in diseased eye tissues. Further investigation revealed that PRL3 plays a crucial role in the abnormal blood vessel growth and leakage that characterizes both wet AMD and diabetic retinopathy.
This serendipitous discovery illustrates how breakthrough medical advances often come from unexpected directions. The same protein mechanism that helps cancer cells invade healthy tissues also contributes to the destructive vascular changes in eye disease. By targeting PRL3, researchers found they could address both problems simultaneously.
“When I first identified PRL3 over two decades ago, I never imagined that our cancer research could also provide hope for patients facing blindness,” said Professor Qi Zeng. “Seeing PRL3-zumab now potentially transform treatment for devastating eye conditions shows how fundamental scientific discoveries can lead to life-changing outcomes.”
How PRL3-zumab Works
Understanding PRL3-zumab’s mechanism requires diving into the cellular chaos that characterizes wet AMD and diabetic retinopathy. Both conditions involve a cascade of molecular events triggered by tissue damage and oxygen deprivation.
When retinal cells become stressed—whether from aging, high blood sugar, or other factors—they release distress signals. These signals activate pathways that promote new blood vessel growth, theoretically to restore oxygen and nutrient supply to damaged areas. However, these new vessels grow improperly, becoming leaky and fragile rather than functional.
PRL3 protein acts as a key orchestrator in this destructive process. It facilitates several cellular changes that promote abnormal blood vessel behavior:
- Enhanced endothelial cell proliferation: PRL3 drives the rapid division of cells that line blood vessels, contributing to excessive vessel growth
- Increased cell migration: The protein helps endothelial cells move and reorganize, enabling new vessel formation in inappropriate locations
- Elevated vascular permeability: PRL3 weakens the barriers between blood vessels and surrounding tissues, causing the leakage that destroys vision
The protein achieves these effects by activating multiple cellular signaling pathways simultaneously. Research has shown that PRL3 facilitates phosphorylation—a cellular switching mechanism—of crucial proteins including ERK1/2, AKT, Paxillin, and SRC. These proteins control fundamental cellular processes like growth, survival, and structural integrity.
PRL3-zumab works by blocking these destructive pathways at their source. As a monoclonal antibody, it binds specifically to PRL3 protein, preventing it from interacting with cellular machinery. This targeted approach addresses the root cause of abnormal blood vessel behavior rather than just treating symptoms.
Laboratory studies using human retinal microvascular endothelial cells demonstrated the precision of this mechanism. When researchers exposed cells to VEGF—a growth factor that promotes blood vessel formation—PRL3 levels increased dramatically. However, cells lacking PRL3 showed no proliferative response to VEGF stimulation, proving the protein’s essential role in disease progression.
The Clinical Trial Advantage
PRL3-zumab enters ophthalmology clinical trials with a significant advantage: extensive safety data from cancer applications. The drug has already completed Phase II trials in cancer patients, providing researchers and regulatory authorities with comprehensive information about its safety profile, dosing parameters, and potential side effects.
This existing safety database accelerates the development timeline considerably. Drug development typically requires 10-15 years and costs over $1 billion, with safety evaluation representing the most time-consuming and expensive component. By repurposing an existing drug with established safety credentials, researchers can focus primarily on demonstrating effectiveness for eye disease applications.
The cancer trial data reveals that PRL3-zumab maintains a favorable safety profile when administered intravenously. Patients tolerated the treatment well, with side effect profiles comparable to other therapeutic antibodies. This foundation provides confidence as researchers prepare to evaluate the drug in a new patient population.
Singapore’s Health Sciences Authority approval on June 16, 2025, represents a major milestone. The regulatory green light allows researchers to begin recruiting patients for the first human trials of PRL3-zumab in eye disease applications. These trials, expected to commence by late 2025, will initially focus on safety confirmation in ophthalmology patients before expanding to larger effectiveness studies.
The trial design will likely compare PRL3-zumab against current standard treatments, measuring not only visual outcomes but also treatment burden and patient quality of life. Success could reshape treatment paradigms for millions of patients worldwide who currently face monthly eye injections.
Global Impact Potential
The implications of successful PRL3-zumab trials extend far beyond individual patient outcomes. These two conditions represent leading causes of blindness globally, affecting populations across all demographics and economic levels.
Wet AMD predominantly impacts older adults, with prevalence increasing dramatically after age 50. As global populations age, the number of affected individuals continues to climb. Current projections suggest that AMD cases will increase by 50% by 2040, driven primarily by demographic shifts in developed countries.
Diabetic retinopathy affects a different but equally significant population. With diabetes rates climbing worldwide, particularly in developing nations, the number of people at risk for diabetic eye complications grows exponentially. The World Health Organization estimates that diabetic retinopathy affects approximately 35% of all people with diabetes, representing hundreds of millions of individuals globally.
Current treatment accessibility remains severely limited. Monthly intravitreal injections require specialized ophthalmology facilities, trained retinal specialists, and sophisticated equipment. These resources concentrate in major urban centers and developed countries, leaving vast populations without access to sight-saving treatment.
PRL3-zumab’s intravenous delivery method could democratize treatment access. Standard IV administration requires less specialized training and equipment than intravitreal injection procedures. This could enable treatment delivery in general medical facilities rather than requiring specialized ophthalmology centers.
The economic implications are equally significant. Current treatment costs exceed $2,000 per injection in many healthcare systems, not including facility fees and specialist consultations. Multiplied by monthly administration requirements over years or decades, the financial burden becomes prohibitive for many patients and healthcare systems.
If PRL3-zumab demonstrates superior effectiveness with less frequent administration, the cost-benefit equation could shift dramatically. Reduced injection frequency, eliminated procedural complications, and broader accessibility could make treatment feasible for previously underserved populations.
Looking Ahead
The upcoming clinical trials represent a critical inflection point for vision care. Success could trigger a paradigm shift from palliative monthly injections to potentially curative systemic therapy.
Several factors suggest optimism for trial outcomes. The 86% improvement in vascular leakage reduction observed in pre-clinical studies significantly exceeds the threshold typically required for clinical significance. The drug’s established safety profile eliminates major risk concerns that often complicate new drug development.
However, challenges remain. Human trials may reveal effectiveness differences between laboratory models and real patient populations. The optimal dosing regimen, administration frequency, and patient selection criteria all require determination through careful clinical evaluation.
The broader implications extend beyond PRL3-zumab itself. Successful drug repurposing could accelerate development timelines for other ophthalmology applications. The approach demonstrates how fundamental research in one medical field can yield unexpected breakthroughs in completely different areas.
Associate Professor Xinyi Su of A*STAR IMCB emphasized this potential: “The repurposing of PRL3-zumab offers the possibility of a faster, more cost-effective and potentially safer path to developing treatments for these eye diseases. This is made possible through the close collaborations in Singapore between our scientists, clinicians and clinician scientists.”
The next 18-24 months will prove decisive. If clinical trials confirm the pre-clinical promise, PRL3-zumab could become available for patient treatment by 2027-2028. For millions of people currently facing progressive vision loss despite monthly injections, this timeline offers genuine hope for preserved sight and improved quality of life.
The transformation from cancer laboratory to ophthalmology clinic illustrates the unpredictable nature of medical innovation. Sometimes the most significant breakthroughs come from unexpected directions, challenging established assumptions and opening entirely new therapeutic possibilities.
As human trials begin, the medical community watches with anticipation. The potential to replace monthly eye injections with effective intravenous therapy could represent one of the most significant advances in vision care in decades.
