Unlocking stem cells’ potential to cure eye disease a reality

For many, patience is a virtue. For Dr. Henry Klassen, it’s been a necessity. For nearly 25 years, he has focused on restoring sight to people suffering from retinitis pigmentosa by creating treatments to regenerate damaged retinal tissue.

Klassen, a pioneer in the field of stem cell research, has seen his patience pay off. This year, a first-of-its-kind, stem cell-based therapy for RP developed in his lab received all necessary approvals and moved into the important clinical trial phase.

His work – and that of dozens of researchers at UCI – are bringing the promise of stem cell research from the lab to patients. Klassen’s clinical trial is the third based on UCI research (two others focus on spinal cord injury) and the first to be held on the UCI campus.

Much of this work is housed in the Sue & Bill Gross Stem Cell Research Center, which is located in Sue & Bill Gross Hall: A CIRM Institute. Both are named in honor of the Laguna Beach couple, who donated $10 million in July 2006 to support stem cell research at UCI. Their support, along with thousands of others, helped raise $1 billion during UCI’s “Shaping the Future” campaign, the first fundraising campaign by an Orange County nonprofit to attempt, and reach, $1 billion.

RP is marked by the slow decay of the photoreceptors – in the shape of rods and cones – that perform the initial detection of light. The disease is known to be caused by mutations in genes important to photoreceptor function. Eventually, the rods die, followed by the cones. People with retinitis pigmentosa first experience night blindness, then tunnel vision and, ultimately, legal blindness.

“We’ve believed it’s possible to rescue and even rejuvenate rods and cones in the degenerating retina,” Klassen says. “Now that our method has been validated, I’m optimistic that stem cell-based treatments will help people with failing vision.”

To date, seven participants with RP – all visually disabled due to the degenerative disease – have enrolled in the trial that tests the use of photoreceptor retinal progenitor cells, which are created from immature retinas formed from retinal stem cells. They have received cell injections, either at the Gavin Herbert Eye Institute at UCI 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, of which UCI is a founding member.

The objective is to preserve vision by intervening at a time when degenerating photoreceptors in the patient’s retina can be protected and potentially reactivated. This is done by introducing these retinal progenitor cells into to the eye to rescue and potentially resuscitate moribund cones, thus reversing the course of RP even at relatively advanced stages.

The open-label phase I/IIa trial is designed to evaluate the safety of these cells 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 under topical anesthesia. Participants will be followed for 12 months; safety and efficacy parameters will be monitored.

The initiation of this clinical trial represents the culmination of a research project stretching back many years – a project, according to Klassen, 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.

Klassen came to UCI in 2006 and is affiliated with the Gavin Herbert Eye Institute and Sue & Bill Gross Stem Cell Research Center, which were both constructed during UC Irvine’s 10-year, $1 billion Shaping the Future campaign. The Discovery Eye Foundation, which aids many UCI efforts to find cures and treatments for corneal and retinal eye disease, also supports his work.

“We are delighted to be moving into the clinic after many years of bench research,” he says.