Can a Retinal Implant Restore Vision in Dry AMD? Phase IIb Trial Underway

USC researchers test whether a stem cell retinal patch can move dry AMD beyond delay.

For a field accustomed to attempting to slow dry age-related macular degeneration (AMD) rather than reversing it, researchers at the University of Southern California (USC) Roski Eye Institute (USA) are asking a more ambitious question. They’ve launched a Phase IIb clinical trial to evaluate whether a stem cell–derived retinal implant can restore vision in patients with advanced dry AMD.

The study is testing an ultra-thin implant composed of lab-grown retinal pigment epithelium (RPE) cells derived from embryonic stem cells. These cells are mounted on a patch designed to replace damaged retinal pigment epithelium (RPE) cells in the macula. Dry AMD is the most common form of the disease and, to date, remains an area with few therapeutic options.

“We are hoping to determine if the stem-cell based retinal implant can not only stop the progression of dry age-related macular degeneration, but actually improve patients’ vision,” said Dr. Sun Young Lee, a retinal surgeon with Keck Medicine and principal investigator of the Keck Medicine study site, in a news release. “The findings could be groundbreaking because while there are a few treatments available that delay the progress of macular degeneration, there are none able to reverse the damage already done.”

Early clinical findings

The Phase IIb trial builds on earlier research conducted at the USC Roski Eye Institute in a small patient cohort. Investigators reported that the implant was well tolerated, remained in position and integrated into retinal tissue. In that early study, 27% of patients experienced some degree of visual improvement.

“The earlier phase of the clinical trial showed the treatment to be safe with the potential to benefit patients’ vision; this next phase will investigate whether the therapy can achieve clinically significant improvements in vision,” Dr. Lee said.

How it works

The implant consists of RPE cells grown in a laboratory and delivered as a thin cellular layer during an outpatient surgical procedure. Surgeons place the implant into the retina with the goal of replacing dysfunctional or absent RPE cells.

“The study will explore if the lab-engineered implant will take over for the damaged cells, function as normal RPE cells would, and improve vision for patients who may currently have no other options for improvement,” said Dr. Rodrigo Antonio Brant Fernandes, an ophthalmologist with Keck Medicine and the study surgeon.

Advancing Eye Care Series: Exploring Dry AMD and GA with Dr. Carolyn Majcher

Trial design and enrollment

Keck Medicine is one of five sites in the United States enrolling patients in the masked trial. Participants will either receive the retinal implant or undergo a simulated procedure.

The study plans to enroll 24 patients between the ages of 55 and 90 with advanced dry AMD with geographic atrophy. Participants will be followed for at least one year to assess implant tolerance and changes in visual outcomes.

Institutional and industry involvement

“The USC Roski Eye Institute is dedicated to furthering innovative treatments to help improve lives by restoring vision,” said Dr. Mark Humayun, co-director of the USC Roski Eye Institute. “Stem cell-derived retinal implants may offer one of the greatest possibilities for helping patients with dry age-related macular degeneration and one day, may offer a cure.”

The bioengineered RPE cell implant is manufactured by Regenerative Patch Technologies (Portola Valley, California, USA), a clinical-stage company focused on stem cell–based retinal therapies. Dr. Humayun co-invented the technology and is a co-founder of the company. The technology is exclusively licensed from the University of Southern California, the California Institute of Technology and the University of California, Santa Barbara.

Funding for the trial is provided in part by the California Institute for Regenerative Medicine, the Marcus Foundation and USC.

Editor’s Note: This content is intended exclusively for healthcare professionals. It is not intended for the general public. Products or therapies discussed may not be registered or approved in all jurisdictions, including Singapore.