Speaking recently to a BrightFocus Chat audience, a leading vision scientist expressed hope for potential treatments for geographic atrophy (GA), one of the major causes of vision loss from age-related macular degeneration (AMD).
Benjamin J. Kim, MD, a physician-researcher at the University of Pennsylvania medical system, stated that there is no approved treatment for GA, which he said remains, “an incredible unmet need,” and “one of the highest priorities in the field of ophthalmology.” Currently, he said, there is more hope than ever before because promising research into new treatments has progressed to late-stage clinical trials.
GA is an advanced form of AMD involving the death of cells (“atrophy”) in the macula, or central area of the eye’s retinal tissue. This atrophy results in dead zones and blindness at the center of the visual field, and sometimes these regions look like a map to the doctor who is examining the retina, hence the term “geographic atrophy.” Advanced AMD has two main types: wet AMD, where fragile leaky blood vessels grow on or near the retina, and GA, as form of dry AMD.
Dr. Kim noted that while many potential treatments for GA have been tested in clinical trials, none have yielded approved treatments. However, Dr. Kim noted there are now encouraging signs in what are known as Phase 3 trials, which are generally the last phase before approval by the Food and Drug Administration (FDA). In the parlance of clinical research, Phase 1 trials are small and primarily assess safety; larger Phase 2 trials further test the safety of a new drug as well as effectiveness; and Phase 3 trials evaluate the drug’s efficacy. If the drug successfully passes Phase 3, it can apply to the FDA for approval to market and prescribe the drug in the US.
The two new treatments Dr. Kim mentioned on the Chat, which are now in Phase 3 trials, work by modifying the complement immune system, an inflammatory pathway that has been “highly implicated as a risk factor and has a strong relationship with macular degeneration,” according to Dr. Kim. The drugs inhibit, or block, different parts of this pathway to calm down activated immune factors that are damaging retinal tissue. Dr. Kim is particularly optimistic because both studies, which were independent from each other, yielded similar results – indicating consistently positive results.
“Pay it Forward” by Volunteering in a Clinical Trial
Dr. Kim encourages patients to enroll in clinical trials, noting that all of our current therapies have been borne from them. Clinical trials are currently investigating whether antioxidants, vitamins, stem cells, and visual cycle modulations can be used to treat GA. Dr. Kim said the variety of approaches gives him hope, because there may be an overlapping cause of AMD. In the future, it is possible that more than one drug can be used at the same time to prevent loss of sight from GA.
“Clinical trials are really what has led to the drugs that we have today, so these treatments for wet AMD, which make a remarkable difference in the lives of these patients, they have only come to approval and they have only come from clinical use as standards-of-care treatments because of clinical trials and because of the patients that participated in those trials,” said Dr. Kim.
“Regulated clinical trials are carefully monitored for both safety and efficacy parameters, and I think it’s something that patients can do to help contribute to the field of medicine. There’s kind of this pay-it-forward aspect to trials, where the drugs that we have now are only available to us because of prior patients that were willing to participate,” he added.
In some clinical trials, groups of patients may receive a placebo, which is a harmless medication, in place of the trial drug. Although those patients are not being “treated,” they are carefully monitored for any downturn in their condition that might imperil their sight. Dr. Kim relayed the importance of placebo groups to look at whether the drug really does work or not. Without looking at data from both sides, it is hard to tell if the drug is truly effective.
Beyond clinical trials, Dr. Kim hopes that further progress will be made in fine-tuning how doctors look for changes in GA lesions. Because these lesions expand at such a slow pace, it takes a long time to study whether drugs have an impact on slowing their growth. Finding a more detailed way to monitor their growth could provide critical data to clinical trials.
For people in intermediate stages of AMD, Dr. Kim mentioned the importance of taking AREDS2 vitamins, an antioxidant formula tested in the Age-Related Eye Disease Studies, two large clinical trials run by the NIH’s National Eye Institute. Even though AREDS vitamins are sold over the counter, it is recommended most people take them under advice from an eye doctor.
For those worried about developing AMD, Dr. Kim encouraged a healthy lifestyle and diet. In particular, it is important to quit smoking, he said. Smoking is a major source of oxidative stress and one of the greatest preventable risk factors for AMD.
For a transcript and audio file of Dr. Kim’s full remarks, visit here.
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