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.

CIRM-funded research aims to create a platform to test therapies for AMD

People with late stage age-related macular degeneration lose their central vision. So an image like the one on the left might appear to them as shown on the right.
Credit: University of California – Santa Barbara

Our vision is one of the most important senses that we use in our everyday lives. Whether its to help somebody perform complex surgeries or soak in a beautiful impressionist painting, a layer of cells in the back of the eye called the retinal pigment epithelium (RPE) provide support to photoreceptors (PRs), specialized cells that play an important role in our ability to process images. Unfortunately, as we get older, problems with this part of the eye can begin to develop.

Age-related macular degeneration (AMD) is an eye disease that causes severe vision impairment, resulting in the inability to read, drive, recognize faces, and blindness if left untreated.  It is the leading cause of vision loss in the U.S. and currently affects over 2 million Americans.  By the year 2050, it is projected that the number of affected individuals will more than double to over 5 million. The dysfunction and/or loss of RPE cells plays a critical role in the loss of PRs and hence the vision problems observed in AMD. One form of AMD for which there is no treatment is known as dry AMD (dAMD) and accounts for about 90% of all AMD cases. This version of dAMD is due to the inability of the RPE cells to heal.

CIRM-funded research at UC Santa Barbara aims to create a platform to test therapies for dAMD. Led by Dr. Peter Coffey and Dr. Lindsay Bailey-Steinitz, the team outlined two main objectives for this project. The first was to better understand what is occurring at the cellular level as the disease advances. The second was to develop a model that could be used to test therapeutics.

In a press release, Dr. Bailey-Steinitz discusses the importance of developing a disease model for dAMD.

“Part of the struggle of finding a treatment option is that we’ve not been able to really model the progression of the disease in cell culture or in animals.”

An overview of Dr. Coffey and Dr. Bailey-Steinitz’s experiment.
Credit: Lindsay Bailey-Steinitz

In dAMD, when RPE cells fail to repair themselves, they form a hole that gradually continues to expand. Dr. Bailey-Steinitz recreated this hole in the lab by culturing RPE cells on a plate with an electrode and then zapping them. This process created a hole very similar to the one that appears in dAMD. However, since the cells used in this experiment were younger cells, they were more prone to self healing. But the team found that 10 pulses of electricity over the course of 10 days prevented the younger cells from healing. The team also found that shocking the cells suppressed important genes involved in RPE cell function.

The team is planning future experiments with older cells since they demonstrate a decreased ability to heal.

In the same press release, Dr. Coffey highlights the potential impact of this work.

“”If we can improve this setup, then we’ve got a therapeutic testbed for AMD.”

CIRM has also funded a separate clinical trial for dAMD conducted by Dr. Mark Humayun at the University of Southern California.

The full results of this study were published in PLOS ONE.

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.