CIRM funded trial for AMD shows promising results

This upcoming July is healthy vision month, a time to remember the importance of making vision and eye health a priority. It’s also a time to think about the approximately 12 million people, 40 and over in the United States, that have a vision impairment. Vision can be something that many of us take for granted, but losing even a portion of it can have a profound impact on our everyday life. It can impact your ability to do everyday things, from basic hygiene routines and driving to hobbies such as reading, writing, or watching a film.

It is because of this that CIRM has made vision related problems a priority, providing over $69 million in funding for six clinical trials related to vision loss. There is reason to be hopeful as these trials have demonstrated promising results. One of these trials, conducted by Regenerative Patch Technologies LLC (RPT), announced today results from its CIRM funded clinical trial ($16.3 million) for advanced, dry age-related macular degeneration (AMD).

AMD is a progressive disease resulting in death of the retinal pigment epithelium (RPE), an area of the eye that plays a key role in maintaining vision. Damage to the RPE causes distortion to central vision and eventually leads to legal blindness. Thanks to CIRM funding, RPT and scientists at the University of Southern California (USC) and UC Santa Barbara (UCSB) are growing specialized RPE cells from human embryonic stem cells (hESCs), placing them on a single layer scaffold, and implanting the combination device in the back of the eye to try to reverse the blindness caused by AMD.

One of the trial participants is Anna Kuehl, a USC alumna and avid nature lover. She was diagnosed with AMD in her mid 30s and gradually began losing the central vision in her left eye. Although her peripheral vision remained intact, she could no longer make out people’s faces clearly, drive a car, or read the time on her watch. This also meant she would have much more difficulty going on the nature hikes she enjoys so much. After receiving treatment, she noticed improvements in her vision.

Anna was not alone in these improvements post treatment. The implant, known as CPCB-RPE1, was delivered to the worst eye of 15 patients with AMD. All treated eyes were legally-blind having a best corrected visual acuity (BCVA) of 20/200 or worse (20/20 indicates perfect vision).

Patients in the clinical trial were assessed for visual function and the results were as follows:

  • At an average of 34 months post-implantation (range 12-48 months), 27% (4/15) showed a greater than 5 letter improvement in BCVA and 33% (5/15) remained stable with a BCVA within 5 letters of baseline value. The improvements ranged from 7-15 letters or 1-3 lines on an eye chart.
  • In contrast, BCVA in the fellow, untreated eye declined by more than 5 letters (range 8-21 letters or 1-4 lines on an eye chart) in 80% (12/15) of subjects. There was no improvement in BCVA in the untreated eye of any subject. 
  • The implant was delivered safely and remained stably in place throughout the trial.
  • Refinements to the implantation procedure during the trial further improved its efficiency and safety profile.

In a news release from RPT, Mark Humayun, M.D., Ph.D., founder and co-owner of RPT, Director of the USC Ginsburg Institute for Biomedical Therapeutics and Co-Director of the USC Roski Eye Institute, Keck Medicine of USC, had this to say about the trial results.

“The improvements in best corrected visual acuity observed in some eyes receiving the implant are very promising, especially considering the very late stage of their disease. Improvements in visual acuity are exceedingly rare in geographic atrophy as demonstrated by the large decline in vision in many of the untreated eyes which also had disease. There are currently no approved therapies for this level of advanced dry age-related macular degeneration”. 

The full presentation can be found on RPT’s website linked here.

Watch the video below to learn more about Anna’s story.

Encouraging news about CIRM-funded clinical trial targeting vision loss

dry AMD

An eye affected by dry age-related macular degeneration

Dry age-related macular degeneration (AMD) is the leading cause of vision loss in the U.S. By 2020 it’s estimated that as many as three million Americans will be affected by the disease. Right now, there is no effective therapy. But that could change. A new CIRM-funded clinical trial is showing promise in helping people battling the disease not just in stabilizing their vision loss, but even reversing it.

In AMD, cells in the retina, the light-sensitive tissue at the back of the eye, are slowly destroyed affecting a person’s central vision. It can make it difficult to do everyday activities such as reading or watching TV and make it impossible for a person to drive.

Researchers at the University of Southern California (USC) Roski Eye Institute at the Keck School of Medicine, and Regenerative Patch Technologies, have developed a therapy using embryonic stem cells that they turned into retinal pigment epithelium (RPE) cells – the kind of cell destroyed by AMD. These cells were then placed on a synthetic scaffold which was surgically implanted in the back of the eye.

Imaging studies showed that the RPE cells appeared to integrate well into the eye and remained in place during follow-up tests 120 to 365 days after implantation.

Encouraging results

Of the five patients enrolled in the Phase 1/2a trial, four maintained their vision in the treated eye, two showed improvement in the stability of their vision, and one patient had a 17-letter improvement in their vision on a reading chart. In addition, there were no serious side effects or unanticipated problems.

There were other indications the implants were proving beneficial.  People with normal vision have the ability to focus their gaze on a single location. People with advanced AMD lose that ability. In this trial, two of the patients recovered stable fixation. These improvements were maintained in follow-up tests.

Abla-8

Abla Creasey, Ph.D., CIRM’S Vice President of Therapeutics and Strategic Infrastructure says even these small benefits are important:

“Having a therapy with a favorable safety profile, that could slow down the progression, or even reverse the vision loss would benefit millions of Americans. That’s why these results, while still in an early stage are encouraging, because the people treated in the trial are ones most severely affected by the disease who have the least potential for visual recovery.”

This study reflects CIRM’s long-term commitment to supporting the most promising stem cell research. The Stem Cell Agency began supporting USC’s Dr. Mark Humayun, the lead inventor of the implant, in 2010 and has been a partner with him and his team since then.

Dr.MarkHumayun2 copy

In a news release Dr. Humayun said they plan to recruit another 15 patients to see if these results hold up:

“Our study shows that this unique stem cell–based retinal implant thus far is well-tolerated, and preliminary results suggest it may help people with advanced dry age-related macular degeneration.”

While the results, published in the journal Science Translational Medicine, are encouraging the researchers caution that this was a very early stage clinical trial, with a small number of patients. They say the next step is to continue to follow the four patients treated in this trial to see if there are any further changes to their vision, and to conduct a larger trial.

 

 

Eyeing Stem Cell Therapies for Vision Loss

Back by popular demand (well, at least a handful of you demanded it!) we’re pleased to present the third installment of our Stem Cells in Your Face video series. Episodes one and two set out to explain – in a light-hearted, engaging and clear way – the latest progress in CIRM-funded stem cell research related to Lou Gehrig’s disease (Amyotrophic Lateral Sclerosis, or ALS) and sickle cell disease.

With episode three, Eyeing Stem Cell Therapies for Vision Loss, we turn our focus (pun intended) to two CIRM-funded clinical trials that are testing stem cell-based therapies for two diseases that cause severe visual impairment, retinitis pigmentosa (RP) and age-related macular degeneration (AMD).

Two Clinical Trials in Five Minutes
Explaining both the RP and AMD trials in a five-minute video was challenging. But we had an ace up our sleeve in the form of descriptive eye anatomy animations graciously produced and donated by Ben Paylor and his award-winning team at InfoShots. Inserting these motion graphics in with our scientist and patient interviews, along with the fabulous on-camera narration by my colleague Kevin McCormack, helped us cover a lot of ground in a short time. For more details about CIRM’s vision loss clinical trial portfolio, visit this blog tomorrow for an essay by my colleague Don Gibbons.

Vision Loss: A Well-Suited Target for Stem Cell Therapies
Of the wide range of unmet medical needs that CIRM is tackling, the development of stem cell-based treatments for vision loss is one of the furthest along. There are a few good reasons for that.

The eye is considered to be immune privileged, meaning the immune system is less accessible to this organ. As a result, there is less concern about immune rejection when transplanting stem cell-based therapies that did not originally come from the patient’s own cells.

The many established, non-invasive tools that can peer directly into the eye also make it an attractive target for stem cell–based treatment. Being able to continuously monitor the structure and function of the eye post-treatment will be critical for confirming the safety and effectiveness of these pioneering therapies.

Rest assured that we’ll be following these trials carefully. We eagerly await the opportunity to write future blogs and videos about encouraging results that could help the estimated seven million people in the U.S. suffering from disabling vision loss.

Related Links:

Stem Cellar archive: retinitis pigmentosa
Stem Cellar archive: macular degeneration
Video: Spotlight on Retinitis Pigmentosa
Video: Progress and Promise in Macular Degeneration
CIRM Fact Sheet on Vision Loss