Rapid progress: An update on corneal endothelial cell therapy

Image credit: Adobe Stock / chokniti

One of the best things about being an optometrist is that I get to witness the rapid pace of ophthalmic innovation and its impact on patients. In my career, we have seen incredible advancements, including anti-VEGF therapies for retinal diseases, optical coherence tomography imaging, lenses and drops to correct presbyopia, and drug delivery to manage various conditions of the eye. Now corneal endothelial cell therapy is making its debut.

The endothelium of the cornea is a delicate but vital monolayer of cells that maintains corneal clarity and proper hydration. Each of us is born with a finite number of these cells; unlike skin cells, for example, corneal endothelial cells do not replicate. Aging, inherited diseases, such as Fuchs endothelial corneal dystrophy, or surgical trauma can cause these cells to die. Once the cells are gone, they’re gone for good. With enough cell loss, the cornea will swell, become cloudy, and impair vision. If left untreated, patients can lose their vision.

Shigeru Kinoshita, MD, PhD, of Kyoto Prefectural University of Medicine in Japan, the inventor of corneal endothelial cell therapy, published a landmark 2018 study in the New England Journal of Medicine¹ reporting
2-year outcomes of a first-in-human trial of 11 patients diagnosed with bullous keratopathy and treated with fully differentiated human corneal endothelial cells produced in the laboratory. Five-year outcomes were published in Ophthalmology in 2020.² The technology was then licensed to Aurion Biotech for further development and commercialization. Earlier this year, Aurion’s cell therapy received regulatory approval from Japan’s Pharmaceuticals and Medical Devices Agency for the management of bullous keratopathy, marking the first regulatory approval in the world for an allogeneic cell therapy to manage corneal endothelial disease. Aurion will soon initiate clinical trials here in the US.

Current standard of care for corneal endothelial disease: Endothelial keratoplasty

Although endothelial keratoplasty (EK) has produced remarkable outcomes in patients, the procedure involves a learning curve for the corneal specialist and requires precision and skill in corneal tissue manipulation. It also requires a ready supply of donor corneal tissue; for every eye with disease, a donor cornea is needed for transplant. Obtaining corneal tissue is not challenging in the US, where we have excellent organ donor networks, but the rest of the world contends with chronic tissue under supply. Globally, there is only 1 donor cornea available for every 70 eyes in need.³ Recovery for patients who undergo EK is uncomfortable, requiring that they lie still (and horizontal) for 1 to 3 days postoperatively.

Corneal endothelial cell therapy: A promising alternative

By contrast, the potential merits of corneal endothelial cell therapy are exciting:

• Abundant supply of corneal endothelial cells. From a single donor, enough cells can be produced in vitro to treat 100 eyes.
• Minimally invasive, accessible procedure. The ophthalmologist makes an incision to remove diseased endothelial cells in the central area of the cornea, then administers the healthy replacement cells in solution with a rho kinase inhibitor.
• Less onerous postoperative recovery for the patient. After receiving the cell therapy treatment, the patient lies face down for several hours. They can then resume normal activities of daily life. Within weeks, vision is restored.

In total, 130 patients have been treated in clinical trials in Japan and in El Salvador. Comparative data from these studies were presented by Matthew Giegengack, MD, one of 4 US surgeons who has performed Aurion’s cell therapy procedure, at the American Society of Cataract and Refractive Surgery Cornea Subspecialty Day 2023 in San Diego, California. Across various cohorts, patients have shown consistent, sustained improvements in both anatomical outcomes (central corneal thickness) and functional outcomes (best-corrected visual acuity), with no adverse safety events.

Since forming in 2021, Aurion has been busy. In addition to achieving the previously mentioned clinical milestones, it has raised additional funds from top-tier biotechnology and industry investors, including Deerfield Management and Alcon, to proceed with US clinical trials.

I imagine 2024 will hold more good news as this cell therapy is launched in Japan and patients receive doses in US trials. I look forward to the day when patients around the world will have broader access to what could be transformational management of corneal endothelial disease.

References
1. Kinoshita S, Koizumi N, Ueno M, et al. Injection of cultured cells with a
ROCK inhibitor for bullous keratopathy. N Engl J Med. 2018;378(11):995-
1003. doi:10.1056/NEJMoa1712770

2. Numa K, Imai K, Ueno M, et al. Five-year follow-up of first 11 patients
undergoing injection of cultured corneal endothelial cells for corneal
endothelial failure. Ophthalmology. 2021;128(4):504-514. doi:10.1016/j.
ophtha.2020.09.002

3. Gain P, Jullienne R, He Z, et al. Global survey of corneal
transplantation and eye banking. JAMA Ophthalmol. 2016;134(2):167-
173. doi:10.1001/jamaophthalmol.2015.477