A team at the USC Dr. Allen and Charlotte Ginsburg Institute for Biomedical Therapeutics and the USC Roski Eye Institute is advancing a new treatment for dry age-related macular degeneration (AMD), a leading cause of blindness in older adults, with the support of a $6 million grant from the California Institute for Regenerative Medicine (CIRM). The funding will facilitate preclinical studies necessary before initiating human trials for a stem cell-derived therapy.
Current Treatment Limitations and Novel Approaches
Mark Humayun, MD, PhD, highlighted the limitations of current treatments, which include AREDS vitamins for early stages and intravitreal injections targeting the complement pathway for later stages. These treatments do not halt disease progression or significantly improve vision in advanced cases. This unmet need has driven the development of a stem cell-derived retinal pigment epithelium (RPE) patch, currently in Phase 2b clinical trials. The patch has demonstrated retinal protection extending beyond the implant site.
Paracrine Effects and Secretome Development
Researchers hypothesize that paracrine effects, specifically beneficial factors secreted by the patch, contribute to the observed results. Years of research have led to the extraction of a secretome from the patch, a mixture of compounds that has shown promise in preventing neurodegeneration in preclinical studies. The CIRM grant supports the transition of this approach from laboratory research to FDA-approved clinical trials.
The program encompasses two potential applications: the RPE patch for advanced AMD and secretome injections for earlier stages of the disease. Preclinical studies have demonstrated safety, with ongoing rigorous testing to ensure regulatory compliance. In Phase 1 trials, the RPE patch improved vision in 27% of patients by at least one line on the eye chart, with these gains sustained over three years.
Challenges and Future Directions
Key challenges include elucidating 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 involve demonstrating safety and efficacy in clinical trials, securing FDA approval, and scaling up production. This approach has the potential to revolutionize AMD treatment by offering earlier intervention with the secretome and advanced care through the RPE patch.
Humayun disclosed affiliations with Regenerative Patch Technologies, which is developing the RPE patch in collaboration with USC and Caltech.
