[Edaily Reporter YU JIN-HEE ] A paradigm shift in the treatment of dry age-related macular degeneration (AMD), which affects approximately 200 million people worldwide, is on the horizon. While existing treatments have been limited to delaying disease progression, a curative therapy that directly replaces damaged retinal cells to restore vision has finally demonstrated long-term efficacy in human clinical trials. Sally Temple, Chief Scientific Officer (CSO) of Luxa Biotechnology (hereinafter “Luxa”), who visited South Korea to deliver a keynote speech at “Bio Plus Co., Ltd.-Interphex Korea (BIX) 2026” recently held at COEX in Seoul, revealed the development achievements and significance of the retinal pigment epithelium stem cell (RPESC) therapy in an exclusive interview with this publication. Luxa is a U.S.-based joint venture of KOSDAQ-listed Y2 Solution(011690).

CSO Temple, who previously served as president of the International Society for Stem Cell Research (ISSCR), is a world-renowned scholar with an unrivaled standing in the field of stem cell biology. In 1989, she published a paper in *Nature*, the world’s most prestigious scientific journal, demonstrating that a single progenitor cell can generate both neurons and glial cells. This was a groundbreaking achievement—the first experimental proof in the world of the existence of stem cells in the mammalian nervous system. For this contribution, he received the MacArthur Fellowship in 2008, commonly known as the “Genius Grant.”

He expanded his research to the retina. He was the first to identify a population of self-renewing stem cells (RPESCs) within the retinal pigment epithelium of adult humans. By demonstrating that regenerative potential is maintained even in the eyes of elderly donors, he fundamentally eliminated the ethical controversies and tumor-inducing risks associated with existing embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). Adult RPESCs are already pre-programmed to differentiate into retinal cell types, ensuring exceptional safety. They engraft simply through the injection of a suspension, without the need for a separate scaffold.

To validate this, Luxa’s Phase 1/2a clinical trial for its dry age-related macular degeneration (AMD) stem cell therapy candidate, “RPESC-RPE-4W,” has fully completed dosing for all 18 patients under approval from the U.S. Food and Drug Administration (FDA). The trial has secured long-term follow-up data spanning 24 months for the low-dose Cohort 1 and interim evaluation data spanning 9 months for the medium-dose Cohort 2. The therapeutic results were groundbreaking. The primary endpoints of safety and tolerability were fully demonstrated. Not a single serious adverse event, such as epiretinal membrane formation, was observed in the low-dose group, which received a transplant of just 50,000 cells.

The efficacy metrics marked a new chapter in regenerative medicine. Based on the Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity chart, patients’ best-corrected visual acuity (BCVA) remained stable over the 24-month period. Notably, the group of severely affected patients, who had experienced extreme vision loss, were able to read an average of 16.6 additional letters compared to before treatment. One line on the ETDRS chart consists of five letters. This means patients were able to identify three or more additional lines. Even the overall average for the low-dose group showed an improvement of 9.3 letters. The difference in visual acuity compared to the untreated contralateral eye averaged 15.3 letters.

We spoke directly with Temple’s CSO about the significance and results of this clinical trial, as well as the future schedule. The following is a Q&A with him.

- All patients in the Phase 1/2a clinical trial have completed dosing. What data should experts pay the most attention to?

△The key points are safety, clear evidence of functional improvement, and the durability of the therapeutic effect. In the first low-dose cohort, only 50,000 cells were transplanted. We confirmed excellent safety without any adverse effects such as rejection reactions or epiretinal membrane formation following the cell transplant. Encouraging results were also observed in terms of visual acuity improvement. Most importantly, the improvement in visual acuity has been maintained for 24 months even after discontinuing systemic immunosuppressants. We are currently verifying whether these therapeutic signals are reproducible in additional patient cohorts.

-According to the Early Treatment Diabetic Retinopathy Study (ETDRS) criteria, what is the clinical significance of an improvement of three or more lines on the visual acuity chart?

△Improvement in central vision completely transforms a patient’s life. Central vision is essential for reading, recognizing faces, driving, and living independently. The group of severely affected patients, whose vision was significantly impaired prior to treatment, was able to read an average of 16.6 additional letters. This means that patients who were legally blind—and unable to perform daily activities—have regained full independence. A treatment that slows disease progression while restoring useful vision offers patients a fundamentally different quality of life.

-How does Luxa’s approach differ from existing treatments such as Apellis’ “Cyphobre” or Astellas’ “Ezbeye”?

△Existing drugs currently approved for geographic atrophy (GA) can partially slow the rate of disease progression. However, they cannot regenerate retinal pigment epithelium (RPE) cells that have already been lost. This presents a critical limitation: they cannot improve vision. Luxa transplants functional cells derived from adult retinal pigment epithelium stem cells (RPESC). The ultimate goal is to directly replace the damaged RPE and preserve the function of remaining photoreceptors to restore visual function itself.

- The reason why the strategy of directly isolating stem cells from adult eyes is attracting attention in the academic community is

△It was first discovered that a population of stem and progenitor cells capable of self-renewal and differentiation exists within the RPE of adult humans. In particular, these cells were successfully isolated even from the eyes of elderly donors. This provides scientific evidence that regenerative potential is maintained over the long term, even in elderly patients. From a therapeutic perspective, this means a plentiful, renewable source of cells has been secured. The foundation has been laid to produce sufficient quantities of cells to treat a large number of patients.

-The advantages over embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are

△ Both embryonic and adult-derived stem cell approaches have their own advantages. Luxa’s RPESC are cells whose differentiation path toward the retinal lineage has already been established. They can proliferate to a significant scale and can be administered as a liquid suspension without the need for a scaffold. The safety profile has been excellent in the patient cohort treated to date. No formation of epiretinal membranes—which often require surgical removal and are frequently reported in pluripotent stem cell clinical trials—has been observed.

- The background behind the “4W” in the pipeline name is unique. Why is the timing of development so important?

△Neural progenitor cells differentiate according to an intrinsic temporal program. In animal models, progenitor-stage cells that had been differentiated for approximately four weeks demonstrated superior tissue engraftment rates and vision preservation compared to fully mature cells. This result stems from directly applying a basic medical discovery—that the developmental stage and timing of administration determine therapeutic efficacy—to new drug design.

- How are innovations in the manufacturing process for mass production and the FDA approval strategy progressing?

△We have completed the development of a cryopreserved cell product. In the past, cells had to be cultured to match each patient’s surgery date. Now, the product is manufactured and stored in advance, then thawed and administered immediately before the procedure. This has dramatically reduced manufacturing costs and resolved the complexities of distribution and logistics. It has also eliminated the risk of cell wastage due to procedure delays. We will fully implement this frozen formulation starting with the next clinical phase. We have received Regenerative Medicine Advanced Therapy (RMAT) designation from the FDA. By securing an expedited review pathway, we are now able to significantly accelerate the pace of global commercialization.

-I’ve heard that support from public institutions such as the U.S. National Institutes of Health (NIH) and the California Institute for Regenerative Medicine (CIRM) was crucial

△Developing cell therapies takes many years, spanning basic biology, process development, and preclinical studies. It is difficult to fund the early stages with private capital alone. Thanks to long-term public investment from the NIH, the National Eye Institute (NEI), and CIRM, we were able to translate discoveries in basic science into clinical trials for patients.

- What is the current status of technology transfer (L/O) discussions with global pharmaceutical companies, and what is the market value?

△The value of regenerative medicine technologies depends on the level of clinical evidence. Safety, the magnitude and durability of efficacy, and mass production capacity are key. If significant and sustained vision recovery is confirmed in a patient cohort with dry age-related macular degeneration, commercial opportunities in the billions of dollars will open up. This is evidenced by the fact that global pharmaceutical and biotech companies are spending trillions of won to secure drugs that are merely disease-modifying therapies. Luxa’s technology is also valued at over $700 million (approximately 1 trillion won).

- What are the synergies from the collaboration with your Korean partner, Y2 Solution?

△The greatest value a partner can provide in cell therapy development is sustained trust and dedication. Our partnership with Y2 Solution has continued unwaveringly for over six years. The scientific and clinical expertise established by U.S. researchers has seamlessly integrated with the manufacturing, engineering, and operational capabilities of the Korean biotech ecosystem, creating a powerful synergy. Thanks to Y2 Solution’s solid financial structure, built on its own cash cow, Luxa has been able to focus solely on development without being swayed by external conditions.