Q&A: Stem cell patch aims to improve AMD vision loss
Key takeaways
- There are no current stem cell treatments that are approved for patients with AMD in the US.
- This phase 2b clinical trial is evaluating the efficacy of the stem cell implant in patients who have suffered vision loss from geographic atrophy.
There are no current therapies to improve vision in patients with advanced age-related macular degeneration, but research on the safety of a stem cell patch has indicated positive results in patients suffering from vision loss, according to researchers.
AMD currently affects more than 1 million people and continues to rise as the age of the population grows. AMD impacts retinal pigment epithelium (RPE) cells and causes them to degenerate over time. This can lead to impaired vision, photoreceptor loss, and even blindness in patients with AMD.
However, recent research into stem cell patches has shown the potential to restore the structure and function of the retina and improve vision, according to researchers at the University of Southern California, including Rodrigo Antonio Brant Fernandes, MD.
Fernandes, an ophthalmologist and associate professor of clinical ophthalmology with Keck Medicine of USC, spoke with Healio about the clinical trial for a stem cell patch treating patients with AMD.
Healio: What are the unmet needs of patients with geographic atrophy?
Fernandes: We have 1.5 million people with dry AMD in the US alone. The incidence of geographic atrophy, which is what we're trying to address here with our study, is around 160,000 people and rising.
There's no treatment approved right now to make those patients that lost the central vision due to geographic atrophy regain vision. We have 2 new drugs approved for geographic atrophy, but their role is to try to make the progression slower. The patients don't have a visual improvement while using the drugs and the treatment is really burdensome.
They have to receive injections every month, and that's really hard to explain to a patient.
Doctors also are frustrated with this because we don't have anything to offer for the patients to improve their vision. The treatment that we're trying to study here may have the ability of restoring some of the vision lost.
The fovea is the region where the best vision is, and normally is the region that we lose when we have geographic atrophy. Now, doctors have very little to offer the patients. And the number of patients with this disease is increasing every year because the lifespan of the population is increasing. People are living longer. The longer patients live, the more prone they are to develop this disease.
There is a great loss of the quality of life of patients that have this disease - they like to watch the television or read and they lose this ability. We really want to have something to offer to them. So far, we have very little to offer for the patients.
Healio: What role do you see stem cell patches playing in the treatment of advanced dry AMD?
Fernandes: The main characteristic of these diseases is that it starts in a layer of cells that's under the retina called pigmented retinal epithelium. Those cells basically stop working as they should. Patients lose vision in that area. We're trying to replace those cells that are in diseased cells with new ones. We’re coaching those cells in the lab; we revive those cells from stem cells so we can have young, healthy and functioning cells in the lab. Our goal is to be able to do tissue transplantation. We're going to get those young cells that we cultured in the lab and we're going to see them in a patch.
We're going to transplant those cells in this area where the RPE cells of the patient are not working anymore. Our hope with this treatment is to stop the disease progression. Hopefully, by creating a better environment by transplanting good cells in the subretinal space and replacing those [with the] disease itself, you’ll have photoreceptors that are still working. They may come back and they can restart some vision to those patients.
We have a safety study that was done with this type of treatment. The first goal of the first study was to see if the implant in the eyes of patients with dry AMD and geographic atrophy could be a safe procedure. We did this safety study with 16 patients in the past, and our conclusions were that the implant, the surgical procedure, and the outcomes are very safe for the patient. The second phase, the phase 2B trial that we're starting now, we're hoping to evaluate efficacy. We're going to see what happens if it can slow the progression. We're very optimistic, but there's a long road ahead before that.
Healio: How were the stem cell patches developed?
Fernandes: It was a joint venture between several institutions. We had cooperation between the University of Southern California, the California Institute of Technology, and the University of California Santa Barbara. USC did the study design and had the idea of doing this stem cell seeded batch. Cal Tech provided the periling patch that we use as a scaffold for the cells. UCSB did all the cell culture of the cells and differentiation from stem cells to RPE cells. We had to use a facility with good manufacturing practices, and that facility was City of Hope. After the study design was developed by those three institutions, the patch was manufactured there, and the surgeries were done here at USC.
There's a lot of research involved, and the end result is not always clear. We always hope for the best. We still have a long way ahead before telling patients that we have something for them in the day-to-day clinic for the doctors and patients.
Healio: What are the main take home messages regarding this trial?
Fernandes: There's a lot of stem cell clinics in the U.S., Thailand, China and Cuba. Those clinics sell treatments that are not approved and they never underwent scrutiny like this treatment. The most important take home message for me is to tell the patients and doctors is that, so far, we don’t have any stem cell treatment that’s approved for use in patients.
Everything is still preliminary; everything is still experimental. It's very important to address this because we know that patients can get very frustrated with their doctors because there's nothing they can do for them in those type of pathologies. They get desperate because they're losing vision. And sometimes they sell their houses to go to Thailand and try something that's not approved. We see that happening multiple times.
It's very important to address that patients should not search for anything now, because nothing is approved, especially if you have to pay for it. Every clinical trial that we do, the first rule of it is that the participants don't pay anything and we also cover all of their expenses regarding the treatment, transportation, food, everything. Don't look for easy answers right now.
They basically can treat everything with stem cells. And nothing's approved. And you're not going to get a good result. You're going to lose your money, and you may further impair your vision. I urge the patients and doctors to wait for the results before doing something that's not approved.
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