Age-related macular degeneration (AMD) is the most common cause of blindness in the United States. The condition can present in two forms, including wet AMD and dry AMD . There is currently no cure for AMD, and there is no cure for the dry form of the disease (other than preventive measures).
Scientists are working hard to find new solutions in the form of advances in macular degeneration, new treatments, and new research that can help people with AMD maintain their vision for as long as possible.
Types of AMD
Dry AMD and wet AMD have different characteristics.
Dry AMD is the most common form of the disease; This is due to the presence of very small yellow deposits, called drusen , that doctors can detect by examining them.
Drusen are present as a normal part of aging; but in drams these deposits begin to grow (in size and / or quantity). This increase in drusen can lead to destruction of the macula (a yellowish oval area near the center of the retina ).
The macula is responsible for a clear and precise vision. The retina is a layer of light-sensitive cells that trigger nerve impulses that are sent to the optic nerve and then travel to the brain where images are formed.
As dry AMD progresses, the drusen begin to grow and / or increase in number, and central vision can gradually deteriorate due to deterioration of the macula.
Dry AMD can turn into a wet form of the disease. Wet AMD involves abnormal blood vessels that begin to develop under the retina. Wet AMD often progresses very rapidly and can lead to vision loss due to swelling or bleeding of these immature blood vessels, resulting in rapid damage to the macula .
Phases of clinical trials
To understand where a potential new drug or treatment lies in terms of how likely it is to be available to the consumer, it is important to understand a little about medical research.
A new drug or treatment must successfully pass several stages of clinical trials before the product can be marketed or sold to the public. There are several stages of medical research , including:
- Phase I. An experimental drug or treatment is tested in a limited number of people (usually 20 to 80 study participants). This initial phase focuses on testing the safety of the drug and identifying possible side effects.
- Phase II – Once a drug or treatment is determined to be potentially safe, it proceeds to Phase II testing to further improve safety. This phase involves a large group (typically 100 to 300 study participants).
- Phase III : After a drug or treatment is determined to be relatively safe and effective, it is retested (in a phase III trial), where scientists evaluate its efficacy and safety against standard treatment. At this stage, a much larger group (1,000 to 3,000) of study participants is involved. Once a drug or treatment goes through this phase, it must be evaluated for approval by the FDA.
- Phase IV : After the FDA approves a new treatment or drug, it is retested in a phase IV trial to evaluate its long-term safety and efficacy in those taking a new drug or receiving a new treatment.
New treatments for wet AMD
If you have age-related macular degeneration, you might be excited to learn that there are several promising new drugs and treatments on the horizon.
According to the American Academy of Ophthalmology, just 20 years ago, if a person developed wet AMD, vision loss was inevitable. But in 2005, an innovative treatment called anti-VEGF was proposed (including drugs like Lucentis, Eylea , and Avastin). ) is it availabe.
These anti-VEGF drugs work to stop the growth of blood vessels, subsequently controlling leakage and slowing down macular damage. According to experts, the treatment is very effective in preserving central vision in people with wet AMD .
What are anti-VEGF drugs?
The abbreviation VEGF, which stands for vascular endothelial growth factor, is a protein that is important for the growth and development of new blood vessels. When injected into the eye, anti-VEGF drugs help stop the growth of these abnormal new blood vessels .
Perhaps the main disadvantage of current wet AMD treatment is the fact that injections (injected directly into the back of the eye) of anti-VEGF medications must be given every four to six weeks.
Now there is hope for new VEGF treatments that will not need to be applied as often as the current four to six week regimen. Some experts say that some of the treatments currently being developed may even cure the disease .
Retinal gene therapy
A promising new treatment for wet AMD includes retinal gene therapy as an alternative to monthly eye injections. The goal of gene therapy is to use the body to create its own anti-VEGF by introducing a harmless virus (called adeno-associated virus / AAV) that carries the anti-VEGF gene into human DNA.
In particular, RGX-314 gene therapy requires only one injection, but must be performed surgically. This drug is currently being prepared for the second phase of clinical trials.
Research on RGX-314
Now that the FDA has approved retinal gene therapy for other retinal diseases (in addition to AMD), this type of treatment looks very promising for people with AMD. RGX-314 can potentially block VEGF for many years after its introduction; This, in turn, will help suppress the development of wet AMD symptoms, the immature blood vessels that carry blood to the retina .
In a phase I / II clinical trial involving 42 people, 9 of the 12 study participants did not require any additional injections of anti-VEGF for six months after a single injection of RGX-314. Furthermore, no side effects were observed during the study .
Another potentially effective gene therapy can be done on an outpatient basis (for example, in a doctor's office). This therapy is called ADVM-022 and it is also in phase II clinical trials. It is estimated that both treatments (ADVM-022 and RGX-314) may be available to people with wet AMD in as little as three years (around 2023) .
Port delivery system
A port delivery system (PDS) is a very small device (smaller than a grain of rice) that can store anti-VEGF drugs. The PDS is implanted in the eye during surgery; it works to provide a sustained release of the anti-FEV drug in the eye.
The port management system can allow people with wet AMD to completely avoid eye injections. The procedure allows people with wet AMD to survive for up to two years without the need for treatment.
You can replenish your supply of medications during your doctor's appointment. But the drug replacement procedure is a bit more complicated than anti-VEGF injections, which are now the standard treatment for wet AMD.
This innovative treatment is now in its third phase of clinical trials and is likely to be available for consumer use for the next three years (around 2023) .
Lucentis Port Management System Study (ranibizumab)
A 2019 Phase II randomized controlled clinical trial (considered the gold label of medical research) published by the American Academy of Ophthalmology evaluated the safety and efficacy of the Port Delivery System with the anti-VEGF drug Lucentis (ranibizumab) for treatment of wet AMD. .
Research has shown that PDS is well tolerated and that in people with age-related AMD, PDS provides a comparable response to monthly injections of anti-VEGF (ranibizumab) into the vitreous (within the back of the brain). eye).
"PDS has been found to be well tolerated and may reduce the burden of treatment [the workload of medical care due to chronic disease] in nAMD [age-related AMD] while preserving vision," they write. the study authors. The study of PDS treatment with ranibizumab (as of 2020) advanced to a stage III study.
Anti-VEGF eye drops for wet AMD are another new treatment for AMD that is in its early stages of clinical trials, but has yet to be used in humans. The treatment has been tested on animals.
Once the medicated eye drops are determined to be safe enough for human use, clinical trials will begin. It may take more than 10 years (around 2030) for wet AMD anti-VEGF eye drops to be available for consumer use .
Anti-VEGF pills that can be taken orally (by mouth) may be available to the public in the next five years (around 2025). The pill form of the drug will allow people with wet AMD to eliminate or reduce the frequency of anti-VEGF injections.
Now, in phase II clinical trials, developers of oral formulations for wet AMD are trying to eliminate errors. The drug now has many side effects, such as nausea, leg cramps , and liver changes.
Once a drug can be considered safe and dangerous side effects have been eliminated, it can be considered for consumption by the consumer.
Long-acting anti-VEGF injections
The pharmaceutical industry is developing several new anti-VEGF drugs to reduce the frequency of injections. These include drugs such as Abicipar and Sunitinab, which are estimated to last approximately three to five years (2023 to 2025) before being approved for consumer use.
Another new drug, Beovu, has already been approved for use in the United States. Beovu injections last up to three months. The breakthrough drug is believed to be more effective at drying up fluid that has built up on the retina due to wet AMD .
Combined drug treatment
The new combination drugs for AMD include drug combinations that are already on the market for the treatment of AMD. The goal is a comprehensive approach to treatment aimed at increasing the effectiveness of medications and prolonging the duration of injections.
One of these combinations is a glaucoma eye drop called Cosopt (dorzolamide-timolol), which is being tested in combination with anti-VEGF injections. Research shows that the two drugs, when given together, can help lower fluid levels in the retina better than anti-VEGF injections alone .
Similar to the type of treatment commonly used to treat cancer, radiation therapy is believed to help slow the growth of abnormal blood vessels caused by wet AMD. Radiation therapy is believed to work in the same way as cancer treatment. It does this by killing fast-growing cells.
But before radiation therapy can be considered the main treatment option for AMD, long-term safety still needs to be evaluated. There are two types of radiation therapy available in the United Kingdom and Switzerland and will soon be tested in the United States. Clinical trials are expected to begin within a year (around 2021) .
New treatments for dry AMD
Most of the time, AMD is associated with a slow-developing type of AMD called dry AMD. Currently, as of 2020, there are no treatment options available for dry AMD, but some promising new treatments are in development.
Stem cell therapy
Stem cell therapy is gaining ground in all types of treatments today, including many forms of cancer and dry AMD. The goal of stem cell therapy for AMD is to allow new stem cells to replace cells in the retina that have been damaged or destroyed by the symptoms of AMD.
Stem cells often enter the body's circulation through intravenous fluids. But researchers are working on how to transplant stem cells directly into the eyes. One strategy is to place the stem cells in a liquid suspension that can be injected under the retina.
Although stem cell treatment for AMD has only been studied in small clinical trials, experts say the treatment is promising. The downside is that stem cells can take another 10 to 15 years (around 2030 or 2035). The therapy has been shown to be effective and safe for consumers.
Exploring stem cell therapy for AMD
A small study in people with wet AMD, published in the New England Journal of Medicine , found that using a person's own stem cells to replace damaged retinal cells resulted in visual acuity for a year after the procedure.
The study authors wrote: "It appears that the surgery helped stop the progression of the disease." While this study does not show that stem cell therapy is effective for dry AMD, many scientists are confident that upcoming research on stem cell therapy for AMD will be promising.
Dry AMD injections
Apl-2 is a drug that can be injected intravitreally (directly into the back of the eye) to help delay the development of dry AMD by protecting the cells of the retina from destruction. This treatment is in a phase III trial and is expected to be available in approximately three to five years (approximately 2023 to 2025) .
Other Possible New Treatments for Dry AMD
There are several other potentially effective new treatments for dry AMD, including:
- Oracea – An oral antibiotic with anti-inflammatory properties that may be available for people with advanced dry AMD. Oracea is currently in Phase III trials and may be available from 2021 .
- Metformin : A drug commonly prescribed for people with diabetes reduces the risk of developing AMD. This may be due to the anti-inflammatory properties of metformin. Since 2020, metformin has been undergoing phase II trials .
Get the word of drug information
Your ophthalmologist (or other healthcare provider) is an expert when it comes to the type of new AMD treatment that might be right for you. There are many factors to consider, such as the type of AMD, its symptoms, the level of progression of the disease, and more.
In addition, there is no single treatment that does not have its drawbacks. Some new therapies may have very few side effects, but the patient selection criteria (the criteria used to qualify as a research participant) can be very strict (for example, for surgically implantable telescopic lenses). Other treatments / medications may have side effects.
Ultimately, it is important to be open to new opportunities as you work with your healthcare team to find the best new AMD treatment for you.