A first-in-kind stem cell–based retinal implant improved visual acuity or function in three of four subjects with advanced dry age-related macular degeneration (AMD) during a Phase I/IIa study, according to physicians and researchers at the USC Roski Eye Institute.
The treatment consisted of a layer of human embryonic stem cell-derived retinal pigment epithelium cells on an ultrathin supportive structure implanted in the retina, the university said. A USC Roski Eye Institute surgeon performed the surgeries on the four patients.
The treatment is designed to replace a single-cell layer that degenerates in patients with dry AMD, said lead author and surgeon for the study, Amir H. Kashani, MD, PhD.
Researchers followed the study’s four patients for up to one year to assess the implant’s safety. There were no severe adverse events related to the implant or the surgical procedure, the university said.
The research team also performed a preliminary assessment of the therapy’s efficacy.
One patient’s visual acuity improved by 17 letters. Two patients gained visual function, as measured by how well they could use the area of the retina treated by the implant, the university said.
None of the patients’ vision worsened, the university said. Researchers noted integration of the implant with photoreceptor cells in all patients.
The study results were published April 4 in Science Translational Medicine.
The study is titled “A Bioengineered Retinal Pigment Epithelial Monolayer for Advanced Dry Age Related-Macular Degeneration.”
It was funded in part by the California Institute for Regenerative Medicine, the university said. Regenerative Patch Technologies also contributed funding to the study.
Mark Humayun, MD, PhD, is the coauthor and lead inventor of the implant. Humayun also co-invented and co-developed the Argus II Retinal Prosthesis System with Second Sight Medical Products.