This review aims to outline the particular approaches in the different published clinical trials for cell-based therapies for retinal diseases.
The retinal pigment epithelium (RPE) is implicated in the pathophysiology of many retinal degenerative diseases. This cell layer is also an ideal target for cell-based therapies. Several early phase clinical trials evaluating
cell therapy approaches for diseases involving the RPE, such as age-related macular degeneration and Stargardt’s
macular dystrophy have been published. However, there have also been numerous reports of complications from
unproven “cell therapy” treatments marketed by “cell therapy” clinics.
This review aims to outline the particular approaches in the different published clinical trials for cell-based therapies for retinal diseases. Additionally, the controversies surrounding experimental treatments offered outside of legitimate studies are presented.
Cell-based therapies can be applied to disorders that involve the RPE via a variety of techniques. A defining characteristic of any cell therapy treatment is the cell source used: human embryonic stem cells, induced pluripotent stem cells, and human umbilical tissue-derived cells have all been studied in published trials.
In addition to the cell source, various trials have evaluated particular immunosuppression regimens, surgical approaches, and outcome measures.
Data from early phase studies investigating cell-based therapies in non-neovascular age-related macular
degeneration (70 patients, five trials), neovascular age-related macular degeneration (12 patients, four trials), and
Stargardt’s macular dystrophy (23 patients, three trials) have demonstrated safety related to the cell therapies, though
evidence of significant efficacy has not been reported. This is in contrast to the multiple reports of serious complications and permanent vision loss in patients treated at “cell therapy” clinics.
These interventions are marketed directly to patients, funded by the patient, lack Food and Drug Administration approval, and lack signifcant oversight.
Currently, there are no proven efective cell-based treatments for retinal diseases, although several
trials have investigated potential therapies. These studies reported favorable safety profiles with multiple surgical
approaches, with cells derived from multiple sources, and with utilized different immunosuppressive regimens.
However, data demonstrating the efficacy and long-term safety are still pending. Nevertheless, “cell therapy” clinics continue to conduct direct-to consumer marketing for non-FDA-approved treatments with potentially blinding