Researchers at the USC Dr. Allen and Charlotte Ginsburg Institute for Biomedical Therapeutics recently reported promising one-year follow up results of a clinical trial using stem cells to treat vision loss.

The phase 1/2a trial set out to assess the safety of a stem cell-based retinal implant the USC Ginsburg Institute team developed to treat dry age-related macular degeneration (dry AMD), which is one of the leading causes of vision loss. A total of 15 patients with severe vision loss underwent surgery at Keck Medicine of USC to receive a stem cell-based implant in their worse- seeing eye. One-year follow up results demonstrated that the implant was not only safe and well-tolerated, but also helped improve vision in its recipients.

Stem cells to rescue a degenerating eye

The disease process of dry AMD involves deterioration of a layer of cells called the retinal pigment epithelium (RPE). RPE cells nourish and support the photoreceptor cells that enable us to perceive light, so when they degenerate, eyesight follows suit. There are currently few medical interventions for the millions of patients who suffer from dry AMD, and given enough time, the disease ultimately progresses to blindness.

Physician-scientists at the USC Ginsburg Institute sought to revolutionize the treatment landscape for dry AMD by utilizing stem cells to replenish the deteriorating RPE cell layer of the retina. To do so, the research team developed a small scaffold made of synthetic material that is safe within the human body and can harbor RPE cells grown from stem cells in a lab. The scaffold is shaped like a champagne bottle and can be inserted into a patient’s retina using a precision tool designed by surgeon-scientists Amir Kashani, MD, PhD and Mark Humayun, MD, PhD at the USC Ginsburg Institute.

Restored sight on the horizons

Clinical trial patients receiving this novel implant were followed for a year post-operation and monitored for any health complications. Prior to surgery, all patients had severe, end-stage forms of dry AMD and were considered legally blind. The trial demonstrated that the implant can be used safely in dry AMD patients, and promisingly, it even resulted in improvements in eyesight in several cases. To help explain the mechanism by which trial patients achieved improvements in visual acuity, the researchers proposed that “dormant” photoreceptor cells in the degenerating area of the retina may be revived by the stem-cell derived implant.

This effort represents the first-ever clinical trial of a retinal implant to treat dry AMD. Its promising early outcomes will pave the way for future studies assessing the implant’s ability to restore eyesight in a much larger cohort of patients, with the ultimate goal of achieving FDA approval as a novel therapeutic for dry AMD.

“We are very hopeful about the results and future directions of this trial,” Humayun said. “There is currently a major unmet clinical need for treatments to help patients suffering from dry AMD, and this stem cell-based therapy represents a large stride in the right direction.”