Therapeutic Patch Derived from Stem Cells
May Someday Restore Vision
A two-layered patch derived from induced pluripotent
stem cells (iPSC) is being developed to restore vision
lost from inherited retinal conditions such as Stargardt
disease and age-related macular degeneration (AMD).
David Gamm, MD, PhD, at the University of
Wisconsin, Madison, and his collaborators have received
significant funding from the Foundation Fighting
Blindness (FFB) to move the innovative therapy toward
a clinical trial.
Many patients with advanced retinal diseases not only
lose photoreceptors, the cells that make vision possible,
but also the retinal pigment epithelium (RPE), which
provides essential support functions for the cells.
One layer of the emerging patch consists of
photoreceptor cell precursors, which are poised to
develop into vision-enabling rods and cones. The other
layer is mature RPE, which provides waste disposal
and nutrition for the photoreceptors. A thin plastic
film developed by Dennis Clegg, PhD, at the University
of California, Santa Barbara, serves as a structural
backbone for the patch. A biodegradable gel protects the
cells and holds the layers together.
The iPSC that develop into photoreceptors and RPE
are derived from small samples of mature human skin
or blood. First, Dr. Gamm and his colleagues genetically
tweak the cells to revert them back to a stem-cell state.
Then, they coax the stem cells forward to become
First Patient Enrolled in USH2A
Natural History Study
FFB’s Clinical Research Institute Clinical Consortium
has launched a four-year natural history study of
people with mutations in the USH2A gene. Mutations
in the USH2A gene are the leading cause of the
combined vision and hearing loss associated with Usher
syndrome type 2A and vision loss from autosomal
recessive retinitis pigmentosa.
This Rate of Progression, or RUSH2A, study, will
follow 100 patients for four years and an additional 20
patients at a single clinical visit. The first patient in the
study has been enrolled at the Retina Foundation of
the Southwest, Dallas, TX, where Dr. David Birch is
the principal investigator. Additional patients will be
enrolled at study sites in the coming months.
“A major challenge in providing prognoses for patients
with USH2A mutations, and in designing clinical trials for
potential therapies, is the wide variability in symptoms,
rates of progression, and severity of the disease,” says
study chair Jacque Duncan, MD, University of California,
San Francisco, Medical Center. “This study will help
the field gain a better understanding of how USH2A
mutations cause vision and hearing loss in some
patients and why other patients with normal hearing at
birth develop vision loss.”
The RUSH2A study is the first project of the FFB
Clinical Research Institute’s Clinical Consortium and
is being coordinated by the Jaeb Center for Health
Research in Tampa, FL. The FFB Consortium is a
network of centers of excellence that will participate in
clinical studies to help accelerate the development of
treatments for inherited retinal diseases. Consortium
studies will provide researchers and clinicians with long-term data about disease onset and progression. The data
gained from natural history studies will identify more
precise ways to measure treatment effects within clinical
RPE65 Gene Therapy Under Review by FDA
A potentially groundbreaking gene therapy for people
with vision loss caused by mutations in the RPE65 gene
was accepted for review by the U.S. Food and Drug
Administration in July and received priority review
status. Priority review is given to treatments that would
offer major advances over existing therapies or where no
adequate treatment currently exists.
The gene therapy, which has a proposed trade name
LUXTURNA™, is a product of Spark Therapeutics.
It helps restore vision by delivering copies of a light-sensitive gene to surviving cells in the retina. The
treatment has the potential to be the first gene therapy
for the eye or an inherited condition in the United States.
It also has the potential to be a one-time treatment
for people living with vision loss due to the specific
FFB provided early funding support toward the
development of this therapy.
A final FDA decision on the treatment is expected
in January 2018.
Summary of recent retinal-research advancements.
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