Mark Humayun, MD, PhD, discusses advance stem cell-derived therapies for dry AMD

The California Institute for Regenerative Medicine (CIRM) has awarded a 2-year, $6 million grant to a team at the USC Dr. Allen and Charlotte Ginsburg Institute for Biomedical Therapeutics and the USC Roski Eye Institute advancing a new treatment for dry age-related macular degeneration, one of the leading causes of blindness in older adults.

The funding will enable the researchers to conduct preclinical studies needed before launching human trials.

Mark Humayun, MD, PhD, discussed the program with Ophthalmology Times. He noted that current treatments include AREDS vitamins for early stages and intravitreal injections targeting the complement pathway for later stages, but these do not halt disease progression or improve vision significantly in advanced cases. This limitation led to the development of a stem cell-derived retinal pigment epithelium (RPE) patch, now in Phase 2b clinical trials, which has shown retinal protection beyond the implant site.

Researchers hypothesize that paracrine effects—beneficial factors secreted by the patch—are contributing to these results. Years of work led to the extraction of a secretome from the patch, a mixture of compounds shown to prevent neurodegeneration in preclinical studies. The CIRM grant supports efforts to transition this approach from laboratory research to FDA-approved clinical trials.

The program includes two potential applications: the patch for advanced AMD and the secretome injections for earlier stages. Preclinical studies have demonstrated safety, with rigorous testing underway to ensure regulatory compliance. In Phase 1 trials, the patch improved vision in 27% of patients by at least one line on the eye chart, with gains sustained over three years.

Challenges include determining the exact mechanisms of action, as the therapeutic efficacy likely depends on a combination of anti-inflammatory and neuroprotective factors rather than a single compound. Future hurdles include demonstrating safety and efficacy in clinical trials, achieving FDA approval, and scaling production. The approach could revolutionize AMD treatment by offering earlier intervention with the secretome and advanced care through the patch.

Humayun disclosed affiliations with Regenerative Patch Technologies, which develops the patch in collaboration with USC and Caltech.