Participants are being enrolled in the first clinical trial that tests the use of retinal progenitor cells to treat retinitis pigmentosa. The product of stem cell research at UCI’s Gavin Herbert Eye Institute and Sue & Bill Gross Stem Cell Research Center, these retinal progenitors are similar to stem cells in terms of potential regenerative properties, but they’re specific to the retina.
To date, four participants with RP – all visually disabled due to the degenerative disease – have received cell injections, either at the Gavin Herbert Eye Institute in Irvine or at Retina Vitreous Associates in Los Angeles. This effort is in conjunction with the California Institute for Regenerative Medicine’s new Alpha Stem Cell Clinic network.
Apart from the ARGUS-II that is only meant for patients with advanced RP, there is no current treatment for this disease, which is considered an “orphan” disease by the Food & Drug Administration, thereby conferring advantages in terms of the regulatory pathway necessary for drug approval.
The open-label phase I/IIa trial is designed to evaluate the safety of retinal progenitor cells injected into the vitreous cavity at two different dosage levels in patients with late-stage RP.
Total enrollment will be 16 patients – up to 12 at UCI – all of whom will receive a single injection of cells into the worse-seeing eye under topical anesthesia. No systemic immune suppression is used. Participants will be followed for 12 months; safety and efficacy parameters will be monitored.
This first-of-its-kind stem cell-based treatment for RP was created by Klassen and Dr. Jing Yang, who co-founded jCyte to sponsor development of the investigational therapy, which is intended to preserve vision by intervening at a time when degenerating photoreceptors in the patient’s retina can be protected and potentially reactivated, as opposed to the more extreme challenge of replacing lost cells.
In addition to the work at UCI, scientists from UCSB, including Dr Geoffrey Lewis & Dr Steven Fisher, worked closely on this research and performed much of the FDA-required pre-clinical work that demonstrated the safety and efficacy of the procedure. They surmised that specific growth factors released from progenitor cells are likely to protect the affected photoreceptors and prevent them from dying, thus preserving the patient’s remaining vision. (source)
The initiation of this clinical trial represents the culmination of a research project stretching back more than a decade – a project accelerated by support from the state’s stem cell agency, the California Institute for Regenerative Medicine, formed in 2004 when voters passed Proposition 71. CIRM granted the team $17 million for the current phase of the project.
Featured image on the top: (c) Dr Geoffrey Lewis, UCSB.