- Researchers want to know if gene therapy can help significantly lessen the treatment burden for people with macular degeneration.
- Age-related macular degeneration affects about 2 million people. It’s one of the leading causes of blindness.
- Other research could someday change how we treat and care for people with this condition.
Age-related macular degeneration (AMD) is one of the leading causes of vision loss and blindness among older adults in the United States.
But now researchers are looking at a potential new treatment that may help prevent this common form of blindness from worsening.
Researchers at multiple sites are currently conducting a phase I clinical trial on a gene therapy that could help patients get fewer injections in their eye to treat the condition.
AMD develops when abnormal blood vessels form at the back of the eye, behind the retina. When those blood vessels leak blood or plasma, it’s known as wet AMD (wAMD).
To reduce vision loss and prevent blindness, people with wAMD have to visit their doctor every 4 to 8 weeks to receive injections of medication in the affected eye. If they miss or skip a scheduled treatment, it can cause their vision loss to worsen.
But treatment might become more convenient in the future, as researchers are currently conducting the phase I clinical trial on a gene therapy that would reduce the number of treatments patients need.
In this experimental therapy, genetic material is inserted into cells in the patient’s eye. This genetic material causes the cells to produce aflibercept, a medication that’s used to treat wAMD.
If this therapy proves to be safe and effective, it may allow doctors to treat wAMD with as little as one injection. After that first injection, the patient’s eye would produce an ongoing supply of its own medication.
“There’s a tremendous treatment burden with respect to our patients with wAMD, [as] many require 10-plus injections per year for their lifetime in order to maintain vision,” Dr. Szilárd Kiss, lead investigator of the study and director of clinical research and chief of the retina service in the department of ophthalmology at Weill Cornell Medical College, told Healthline.
“With this new in-office intravitreal gene therapy, there is potential for a ‘one-and-done’ approach that can not only completely alleviate that treatment burden, but perhaps result in improved visual outcomes,” he added.
Reducing the treatment burden on people with wAMD isn’t just a matter of convenience.
When patients find it hard to stick to their treatment plan, it can lead to worse outcomes.
“We know from other work that’s been done that one of the biggest determinants of how well patients maintain their vision over the years is how often they receive medicine,” Dr. Sunir Garg, a clinical spokesperson for the American Academy of Ophthalmology and a professor of ophthalmology at Wills Eye Hospital in Philadelphia, told Healthline.
“Not getting treatment as often as the eye would require, that’s a big cause for progressive vision loss over time,” he continued.
Attending monthly or bimonthly visits with a doctor can be challenging for anyone, but patients with wAMD often face more barriers than many. Due to vision loss, they may not be able to drive themselves to their appointments, and may depend on others to get them there.
If scientists can develop a treatment approach that requires fewer doctor visits, that could have a substantial effect on a patient’s ability to stick to their treatment plan.
If all goes according to plan, Kiss hopes a gene therapy for wAMD may be available within 3 to 5 years.
Earlier this month, he reported promising preliminary results from his phase I clinical trial at the 123rd Annual Meeting of the American Academy of Ophthalmology.
So far, his research team has enrolled 12 patients in the first two cohorts of the trial. They’re continuing to enroll patients in the third and fourth cohorts.
Among the six patients who’ve already received the gene therapy, all of them have gone at least 6 months without needing additional injections.
Patients in the first cohort experienced inflammation in the treated eye, but Kiss said it was “generally mild and manageable with steroid eye drops.” He added that “control of this inflammation will be paramount to the success of this therapy.”
Although the trial is ongoing, the early results are encouraging, says Dr. Matthew Gorski, an ophthalmologist at Northwell Health in Great Neck, New York. However, more research is needed to test this experimental treatment.
“While the findings of the study are encouraging and provide hope for an improvement in the current ways to treat AMD,” Gorski said, “further studies with many more patients are needed to confirm the results and prove that this therapy is safe.”
After Kiss and colleagues finish their phase I clinical trial, they plan to launch a larger, prospective, multicenter controlled clinical trial to further study their gene therapy.
This isn’t the only potential breakthrough for AMD treatment. Other studies are also underway to develop and test more convenient and consistent methods of delivering treatment to people with wAMD.
In other gene therapy trials, scientists have been testing methods of surgically administering gene therapy under the retina, rather than using an injection that can be administered in a doctor’s office.
Scientists have also been studying a treatment approach known as the Port Delivery System, in which an urnlike reservoir is implanted in the eye and periodically filled with medication. This medication is meant to slowly diffuse into the eye, reducing the need for frequent treatments.
“Time will quickly tell if one of those treatment models, or more than one of them, will end up helping our patients,” Garg said.
But for now, he emphasizes the importance of getting early and consistent treatment with the injections that are currently available.
When patients seek treatment early and follow their recommended injection schedule, it can prevent additional vision loss and sometimes reverse vision loss that’s already occurred.
“Most patients don’t mind coming in, because they know the current medicine helps them a lot,” Garg said.
“If we start to treat it earlier, that makes a huge difference to long-term outlook,” he added.