- About 170 million people globally live with age-related macular degeneration (AMD)
- About 15% of all AMD cases are wet AMD, which is a more severe form of the disease.
- Researchers report that one commonly used wet AMD drug outperformed another drug when it comes to helping people safely wean from treatment without further vision loss.
About 170 million people around the world have age-related macular degeneration (AMD) — a progressive eye disease affecting a person’s vision.
Advanced AMD is considered the leading cause of visual impairment and irreversible blindness globally.
Of the two types of AMD — wet and dry — about 15% of all AMD cases are wet AMD, which is a more severe form of the disease. There is currently no cure for either type of AMD.
Now, researchers from the Wilmer Eye Institute at the Johns Hopkins University School of Medicine in Maryland report that one commonly used wet AMD drug outperformed another drug when it comes to helping people safely wean from treatment without further vision loss.
The study was recently published in The Journal of Clinical Investigation.
What is wet AMD?
AMD occurs when the macula of the eye — which is part of the retina that controls straight-ahead vision — becomes damaged. The damage may occur from aging or genetic or environmental factors.
Most people with AMD will have dry AMD, where deposits called drusen form within the retina, affecting vision.
Wet AMD occurs when abnormal blood vessels begin to grow in the back of the eye. These vessels can leak lipids, damaging the macula and retina.
Symptoms of wet AMD include:
- blurred vision
- reduced central vision
- straight lines that appear wavy or bent
- dark or blind areas in your vision
- need for brighter light to read
Risk factors for developing AMD include:
- family history of the disease
- age — people 55 or older are at a higher risk
- smoking
- obesity
- high blood pressure
- poor diet
There are currently no therapies that can reverse either type of AMD. However, there are ways doctors can help slow the progression of the disease.
Currently, there are two main medications doctors use to help slow the progression of wet AMD — aflibercept and bevacizumab.
Comparing wet AMD treatments
According to Dr. Akrit Sodhi, an associate professor of ophthalmology at the Wilmer Eye Institute and lead author of this retrospective study, the researchers decided to focus on aflibercept and bevacizumab as they are the two most commonly used drugs for the treatment of people with wet AMD.
“The decision to choose one over the other remains an area of debate,” Sodhi told Medical News Today. “We wanted to know if the choice of one of these two drugs influenced the success of weaning patients with wet AMD off anti-VEGF therapy.”
For this study, Sodhi and his team examined data from 106 people with wet AMD treated at the Wilmer Eye Institute. Each person received a monthly injection for the first three months of therapy with either aflibercept or bevacizumab.
At each follow-up visit, if a person’s wet AMD was deemed inactive, the time between visits was extended by two weeks. If that interval could be safely increased to 12 weeks, treatment was paused and the person was monitored by doctors without treatment.
People who had stable vision and did not require an eye injection for at least 30 weeks were considered “weaned” off treatment.
Upon analysis, the research team reported that 50% of people treated with aflibercept were considered weaned off therapy after a one-year period, compared to 27% of people treated with bevacizumab.
For people who still required injections, the intervals between them were 44% longer for people treated with aflibercept than those treated with bevacizumab.
“Prior studies have suggested that aflibercept may have some benefits over bevacizumab for the treatment of wet AMD,” Sodhi said. “Compared to bevacizumab, aflibercept lasts longer — allowing for longer intervals between treatments — and appears to be more effective at reducing fluid when using the same treatment interval.”
“However, these differences are modest and whether they justify the 10- to 20-fold higher cost of aflibercept compared to bevacizumab is still under debate,” he added.
A hybrid treatment protocol
Sodhi said this study was an extension of a prior study on a treatment protocol that researchers termed treat-and-extend, pause, and monitor (TEP/M).
“TEP/M is a hybrid of the two most common treatment protocols currently used by retina specialists for their patients with wet AMD: ‘treat-and-extend’ (TAE) and ‘as needed’ (or PRN),” he explained. “The TAE approach allows clinicians to personalize the treatment interval to a specific patient, while the PRN approach only provides treatment when patients demonstrate active disease.”
“The TEP/M protocol combines the ‘personalized’ approach of TAE but allows clinicians to hold treatment for patients who demonstrate inactivity — ‘quiescence’ — of their disease,” Sodhi added.
Since the TEP/M approach is designed to optimize an individual patient’s response to anti-VEGF therapy, Sodhi said the researchers anticipated that people receiving aflibercept would have a longer treatment interval compared to those receiving bevacizumab, and, in turn, require fewer injections.
“This proved to be true and is consistent with prior studies,” he noted. “However, we did not expect there to be a significant difference in the number of patients who could successfully enter a treatment pause.”
“Although unexpected, the observation that aflibercept was more effective than bevacizumab at successfully weaning patients off therapy was consistent with our prior observation that patients who were weaned off treatment were those who had little or no fluid after their first three months of treatment,” Sodhi added. “Patients with wet AMD receiving aflibercept were also more likely to have little or no fluid after three months of treatment compared to those receiving bevacizumab.”
Dr. Sodhi stated as these reported observations are from a retrospective study, the results should be interpreted cautiously.
“We are currently planning to corroborate and extend these results in a prospective clinical trial,” he continued. “We are also working on studies to try to identify biomarkers that can help predict which patients respond best to current anti-VEGF therapies. This may provide additional information to help clinicians decide which therapies to offer their patients with wet AMD.”
Next research steps
Medical News Today also spoke with Dr. Thomas Hanscom, an ophthalmologist and retina specialist at Providence Saint John’s Health Center in California who was not involved in this research.
He said he entirely agrees with the underlying point of the research, which is that aflibercept is a superior drug compared to bevacizumab.
“This is kind of an old battle because both bevacizumab and aflibercept have been out for 10 years,” Hanscom said. “The next step is really further data collection on the next generation. There’s a new drug called Vabysmo, which is Faricimab made by Genentech, which already has been shown to have a superior duration of effect over aflibercept.”
However, he did raise concerns over some structural issues with the study and the term “weaning.”
“Weaning sounds good — that’s what everybody wants is to have people stop these injections,” Hanscom explained. “If you look at the other major literature on this condition, nobody ever uses the word weaning.”
“In one paragraph (the study authors) define weaning as not needing treatment for 30 weeks — that’s not really weaning,” he continued. “That’s saying I’m going to inject every 30 weeks, which is better than every two months. So the definition of the term weaning is vague.”
“There is a minority – 10 percent or 20 percent – that after years, especially when the patient gets very advanced age, usually over 90, some of those people seem to require far fewer injections,” Hanscom added. “But to say 43 percent of people on aflibercept can be weaned is far outside the normal literature.”
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