Over the past few days, there has been much excitement about the latest clinical trial involving stem cells. With headlines boasting a new “stem cell treatment to cure vision loss” – of course people are excited! But, what does this really mean? In this new spotlight on stem cells, we’ll dig a little deeper to get a better understanding of what this latest announcement means for the millions of people who are living with vision loss and eagerly awaiting some kind of treatment.
Just over a year ago, everyone was buzzing about stem cells and age-related macular degeneration. Around the world, people were celebrating the landmark clinical trial that was using a patient’s own stem cells to treat her age-related macular degeneration (AMD). In short, it was the first clinical trial involving induced pluripotent stem cells, also known as iPSCs, which had been coaxed into becoming retinal pigmented epithelial (RPE) cells. Next, in October – before the excitement died down – Advanced Cell Technologies, announced positive early results of their clinical trial that involved transplanting stem cells to treat Stargardt disease and AMD. Again, this was a trial with RPE cells.
Around this time, we were getting so many questions from our community about stem cell therapeutics that we wrote this spotlight on stem cells to try and bring everybody up to speed. It was one of our most popular stories all year! The thing with research is that it never stops. So much has happened over the past year; it’s time for another stem cell spotlight.
Many people who read this latest headline about curing blindness will wonder if the same kind of treatment might work for them or their loved ones. This stem cell spotlight is designed to help you find an answer to your question: will it work for me? To get an answer, we suggest that you should be paying attention to three key points when you read stories about emerging stem cell clinical trials. First: the kind of stem cell matters (for example, is it an embryonic stem cell, a progenitor cell, etc.). Second: the kind of eye cell matters (for example, is it an “RPE” cell, a photoreceptor cell, etc.). And, third: the kind of trial matters (for example, is it phase I, phase II, randomized, etc.).
1. The Kind of Stem Cell Matters
There are lots of different kinds of stem cells. There are embryonic stem cells, neural stem cells, blood stem cells, skin stem cells, eye stem cells, induced pluripotent stem cells… the list goes on. Importantly, these different kinds of stem cells can do different things. Therefore, it matters if a new clinical trial involves embryonic stem cells or neural stem cells. It matters because embryonic stem cells have the ability to make all of the different cell types that are needed to make a human body. In contrast, neural stem cells can only make brain cells. Because these cells have different properties, there are different safety concerns involved. For example, some people are concerned about using embryonic stem cells (ESCs) for therapeutic purposes because there is a worry that ESCs will start producing the wrong cell type in the wrong place.
Just a few months ago, we shared a story about another stem cell headline that was celebrating a new stem cell based clinical trial for retinitis pigmentosa. We wrote a story to explain the trial in more detail and also to let people know that this trial does not actually involve stem cells, but rather retinal progenitor cells. This distinction matters because this particular trial is not planning to regenerate lost tissue, which is an assumption that people often have when they think about stem cells.
2. The Kind of Eye Cell Matters
Stem cells can make lots of different kinds of eye cells. For example, the latest headline story involves transplanting a kind of eye cell called retinal pigmented epithelial (RPE) cells to treat wet age-related macular degeneration (AMD). All of the ongoing clinical trials for vision loss involve RPE cells. RPE cells are not the light-sensing cells in the eye. They are the support cells. This new trial is groundbreaking because it is trying to replace the RPE cells in people with wet AMD who have recently experienced rapid vision loss. The unique goal of this trial is to replace the damaged RPE cells and, as a result, restore the lost sight before the photoreceptors become too damaged. If this works, it would be a tremendous breakthrough and it could be life changing for people who might be diagnosed with wet AMD. This approach has the potential to save lost vision before it’s irreversible.
Unfortunately, transplanting RPE cells can’t restore vision to the majority of people who are currently living with low vision or who are completely blind. In many of these cases, the only way to restore vision is to replace damaged photoreceptors, which are the eye’s light-sensing cells. There are two different kinds of photoreceptors: cones and rods. Cones are needed for high acuity central vision and rods are needed for low light and peripheral vision. Around the world, scientists are trying to use stem cells to make rods and cones. It is not easy!! Photoreceptors are much more complicated cells than RPE cells. Fortunately, scientists have been making amazing progress. The Foundation Fighting Blindness is proud to support Dr. Gilbert Bernier’s incredible work with cone photoreceptors; Dr. Valerie Wallace’s work with cone photoreceptors, and Dr. Saeed Khalili’s work to design better transplantation methods. We are proud that many of these people are collaborating to drive photoreceptor research forward.
In summary, if you are blind or losing your vision because your disease is damaging your photoreceptors, then you should be on the lookout for research and clinical trial announcements about photoreceptors, not just stem cells (because often these stem cell headlines are referring to RPE cells and not photoreceptors).
3. The Kind of Trial Matters
There are many different kinds of clinical trials. In a clinical trial, participants receive some kind of intervention (such as drugs or transplanted stem cells). Clinical trials involve dividing the participants into groups so that the new intervention can be compared to an alternative, which may be an existing treatment or a placebo. The main goal of a clinical trial is to determine if the new intervention is safe and effective. The word intervention is used instead of the word treatment to help people remember that the drug and/or surgery that the participant is receiving is not an established treatment. A clinical trial is not a treatment it is an experiment. It is not surprising, however, that many participants are very hopeful that a clinical trial might benefit them. This latest trial to treat wet-AMD is a Phase I/II clinical trial, which means that it will evaluate the safety this new approach and also measure if there is any benefit to the patient. An important thing to remember about clinical trials is that it should never cost you money to participate. You are participating in research and this should be communicated to you clearly.
Will this new stem cell treatment work for you? Only time will tell. At the Foundation Fighting Blindness we have a lot of hope about the future of stem cell therapeutics to treat vision loss. This is why we are investing so much in stem cell research. And, with every new announcement, our confidence in the future of stem cell based treatments for vision loss grows stronger. But, we also know that it will take time, effort and teamwork to really translate science into new, accessible therapies.
What can you do while you wait? Enroll on the Foundation Fighting Blindness Patient Registry, which is a tool that is designed to connect people living with inherited eye diseases to clinical trials. Attend Vision Quest, where you can ask scientists and doctors about what’s coming next. And, help us to raise awareness about the importance of vision research. We know that research is a long-term investment, but it is changing the future.