The Spectacular Now: The Marvel of Stem Cells
Dr. Feigal says one of CIRM’s goals is to help the most promising projects—those that are not only safe but also likely to improve many lives and have measurable outcomes—to move as quickly as possible through the regulatory process. Within the next decade, she expects several therapies to gain US Food and Drug Administration (FDA) approval, including those to treat macular degeneration.
A leading cause of vision loss in Americans ages 60 and older, age-related macular degeneration provides an ideal situation to learn about applying stem cell therapies, says Steven Schwartz, MD, of the Jules Stein Eye Institute at UCLA. “The eye is a perfect target for a number of reasons: You may not need a lot of therapeutic cells; you can detect the cells with both diagnostic imaging and clinical examination; and after they are transplanted, you can measure their function” with non-invasive diagnostic studies, Dr. Schwartz explains. Patients who receive the treatment may not need a cocktail of immunosuppressant drugs, because parts of the eyes are “immunoprivileged,” meaning they typically mount less of an immune response compared to other organs.
Dr. Schwartz is currently leading two Phase 1 clinical trials, testing the safety of stem-cell therapy in patients with age-related macular degeneration and Startgardt macular dystrophy, a form of macular degeneration found in younger people. He and his colleagues use embryonic stem cells (which they chose, in part, because they are scalable and the science is much further along) to make retinal pigment epithelial cells, which they place beneath the retina. Early results are positive: The first patients seem to have experienced no safety problems, such as abnormal cell growth, and they say they are seeing more clearly. “Vision is very hard to measure and quantify in patients who are nearly blind and legally blind to begin with,” Dr. Schwartz says. Sometimes seeing just a few letters on an eye chart is a major improvement. “In this early uncontrolled study, we have had some patients who seem to be seeing much better and others in whom we cannot tell if the improvement is real or a placebo effect,” Dr. Schwartz says. “I cannot quantify that right now, except to say that, if the results hold up, they will be pretty hopeful.”