One of the more exciting aspects of FFB’s recent annual conference, VISIONS 2013, was the news on the clinical development of several emerging stem cell therapies. The field has picked up a lot of steam, with many new human studies of stem-cell treatments anticipated to begin in 2014 and 2015.
What’s particularly noteworthy is that some of these trials will be for people with retinitis pigmentosa (RP) — a population not yet included in human stem-cell studies. Also, investigators will evaluate new types of cells and new, innovative approaches to implanting them.
Here’s a review of three of the stem-cell clinical studies on the horizon:
Riken Institute: Sheets of RPE Derived from Induced Pluripotent Stem Cells
In June, the Japanese Health Ministry gave approval to the Riken Institute to launch a clinical trial of sheets of retinal pigment epithelial (RPE) cells for the treatment of wet age-related macular degeneration (AMD). The study is planned for 2014.
The sheets will replace native RPE cells damaged by leaky blood vessels, which are the hallmark of wet AMD. RPE cells play a critical role in supporting photoreceptors, the cells that make vision possible.
For the first time in a human study, the researchers will produce RPE cells from induced pluripotent stem cells (iPSC) — stem cells derived by turning back the development clock on a small sample of skin taken from the patient. The stem cells are then coaxed forward to become RPE. Because the cells come from the patient, there’s less chance of immune rejection.
David Gamm, M.D., Ph.D., of the University of Wisconsin-Madison, said that transplanting sheets of RPE cells — rather than injecting a bolus or a clump of cells — was likely to produce better results, because RPE cells naturally occur as a layer in the retina. He believes that sheets of cells have a better chance to integrate and function normally.
By the way, Dr. Gamm, in collaboration with Dennis Clegg, Ph.D., of the University of California, Santa Barbara, is receiving Foundation funding to develop a patch of cells — comprised of photoreceptors and RPE cells — for treating retinal diseases. While his work is still a few years away from the clinic, it is very promising, because so many retinal diseases affect both of these cell types.
UC Irvine: Retinal Progenitor Therapy for Reactivating the Retina
Henry Klassen, M.D., Ph.D., of the University of California, Irvine, and a former recipient of a Foundation Career Development Award, is planning to launch a clinical trial of a stem-cell therapy for people with RP. He hopes to begin the study in late 2014 or early 2015.
His treatment involves the transplantation of progenitor stem cells — cells that have partially developed into retinal cells. Based on results from his lab studies, he believes the progenitors will rescue and reactivate dormant cones in the retinas of people with early- and late-stage disease.
Not only is Dr. Klassen an outstanding scientist, he’s resourceful and collaborative — qualities that will undoubtedly enhance his chances of success. He obtained a $17.3 million grant from the California Institute of Regenerative Medicine, a legislative initiative providing $3 billion in funding over 10 years for stem cell research in facilities throughout California. Dr. Klassen’s project was also accepted into the Therapeutics for Rare and Neglected Diseases (TRND) program established by the National Institutes of Health to speed the development of new treatments for rare and neglected diseases. TRND will provide him with specialized expertise and resources to help advance his efforts.
ReNeuron: Retinal Progenitor Therapy for Replacing Lost Photoreceptors
One of the more ambitious stem-cell treatments nearing human study is being developed by ReNeuron, a company from the United Kingdom. Its retinal progenitor treatment replaces photoreceptors lost to retinitis pigmentosa. When transplanted in the retina, ReNeuron researchers believe that the partially developed cells will mature into fully functional photoreceptors. The company hopes to launch a clinical trial, probably in the U.K., in the next year or two.
Previously funded by the Foundation, Michael Young, Ph.D., of Schepens Eye Institute, Massachusetts Eye and Ear Infirmary, conducted much of the research making this treatment approach possible. His work included the development of a biodegradable scaffold for growing and organizing the cells prior to transplantation. The structure increases the chances of survival and integration of the therapeutic cells.
But Wait — There’s More
Fortunately, there are far too many promising stem-cell research efforts to cover in one post, so here are links to other retinal-disease projects:
- ACT Expands Clinical Trial of Stem-Cell-Derived Retinal Treatment
- Bone Marrow Stem Cells in Clinical Trial for Retinal Diseases
- Stem Cells, Inc. Launches Clinical Trial for Dry AMD Treatment
Pictured, above: partially developed retinal tissue derived from induced pluripotent stem cells. Courtesy of Dr. David Gamm.