Luxa Doses First Participant in Clinical Trial of RPE Stem Cells for Dry AMD Patients

Luxa Biotechnology has announced transplantation of retinal pigment epithelial stem cell-derived RPE (RPESC-RPE-4W) in the first participant in its Phase 1/2 clinical trial for people with dry age-related macular degeneration (dry AMD). Dr. Rajesh Rao, the trial principal investigator at the Kellogg Eye Center, University of Michigan, transplanted 50,000 RPESC-RPE-4W cells under the macula of a legally blind participant with dry AMD. The 18-participant trial starting in Ann Arbor, Michigan, is the first in human study of RPESC-RPE-4W for the treatment of a retinal disease. The trial is evaluating three different cell doses: 50,000, 150,000, and 250,000 cells.

RPE cells provide critical support functions, including nutrition and waste management, for the photoreceptor cells that initiate vision in the retina. In macular conditions such as AMD, the dysfunction and degeneration of RPE cells leads to loss of photoreceptor cells and central vision that can progress to legal blindness.

Sally Temple, PhD, and Jeff Stern, MD, PhD, scientific co-founders of Luxa and the Neural Stem Cell Institute (NSCI), explained that the RPESC-RPE-4W cell product used in the trial consists of progenitor stage cells, not mature RPE cells. The decision to use progenitor stage cells reflected years of study in the NSCI research labs that demonstrated progenitor cells derived from the adult human RPESC are more effective at rescuing vision in animal models than fully mature RPE cells.

The RPESC-RPE-4W cell product is derived from adult human RPE stem cells that haven’t quite become mature RPE cells but whose fate is determined to produce RPE. These progenitor cells destined to produce RPE progeny show no evidence of unwanted cell growth or tumor formation. The RPESC-RPE-4W cells used in the Luxa trial were obtained from donated eyes deposited in eye banks. Cells obtained within 36 hours of the donors’ passing are used to make cell banks that are expanded and frozen for subsequent transplantation. Clinical manufacture is carried out at the Cedars Sinai Biomanufacturing Center in Los Angeles. Emmes Corporation manages the trial bringing extensive experience with clinical measures of AMD. The trial is co-sponsored by the National Eye Institute of the National Institutes of Health under a Regenerative Medicine Innovation Project cooperative agreement.

Several companies and researchers are evaluating stem cell-derived RPE cells in clinical trials for the treatment of AMD. Mature RPE cells in these trials are usually derived from human embryonic stem cells or induced pluripotent stem cells, the latter of which are developed by taking a small sample of skin or blood cells and genetically tweaking them, so they revert back to a stem-cell state. The Luxa product is different because it is derived from a unique adult stem cell that is normally present in the adult human eye.   

Over the last several years, Drs. Temple and Stern performed extensive studies of human RPESCs to understand how these cells can be harnessed for retinal repair in conditions such as dry AMD. Dr. Stern expressed his hope that the first in human clinical trial will result in outcomes that reflect the highly promising preclinical findings they have made in the research lab: “If we can successfully repair the RPE layers by cell transplantation, we can potentially provide meaningful improvement in vision and in the lives of patients suffering from dry AMD, which is our goal.”