Anti-VEGF therapy represents a significant advancement in treating various medical conditions. This treatment targets Vascular Endothelial Growth Factor (VEGF), a naturally occurring protein within the body. VEGF plays a role in the creation of new blood vessels, a process known as angiogenesis. Anti-VEGF therapy involves a class of medications specifically designed to interfere with the activity of this protein. By blocking VEGF, these therapies aim to manage conditions where excessive or abnormal blood vessel growth contributes to disease progression.
The Role of VEGF and How Anti-VEGF Works
Vascular Endothelial Growth Factor normally functions in the body’s repair processes, such as wound healing, by stimulating the formation of new blood vessels to restore oxygen supply to tissues. This protein is also involved in embryonic development and muscle repair after exercise.
In certain disease states, however, cells can produce an excess of VEGF. This overproduction leads to the growth of abnormal, fragile, and leaky blood vessels. These aberrant vessels can cause fluid accumulation, bleeding, and scarring, disrupting normal tissue function.
Anti-VEGF drugs work by binding directly to the VEGF protein, preventing it from attaching to its receptors on cell surfaces. This action effectively blocks the signal for blood vessels to grow and leak, much like a key being prevented from entering a lock. By neutralizing VEGF, these medications reduce leakage, shrink abnormal vessels, and help stabilize or improve affected tissues.
Medical Conditions Treated with Anti-VEGF
Anti-VEGF therapy has improved the treatment of conditions where abnormal blood vessel growth causes harm. These treatments are extensively used in ophthalmology and have applications in oncology.
Ophthalmology
In the eye, anti-VEGF medications are commonly injected to treat conditions like wet age-related macular degeneration (wet AMD), diabetic retinopathy, and macular edema. Wet AMD involves the growth of abnormal, leaky blood vessels under the macula, the central part of the retina responsible for sharp, detailed vision. These vessels can bleed or leak fluid, leading to rapid central vision loss.
Diabetic retinopathy, a complication of diabetes, can cause damage to retinal blood vessels, leading to swelling and abnormal vessel growth and leakage. Similarly, macular edema involves fluid buildup in the macula due to leaky vessels, which impairs vision. Anti-VEGF drugs like ranibizumab (Lucentis), aflibercept (Eylea), and bevacizumab (Avastin) are frequently used for these eye conditions.
Oncology
In cancer treatment, anti-VEGF therapy helps to starve tumors by inhibiting their ability to grow new blood vessels. Without an adequate blood supply, tumors cannot grow beyond a limited size and may limit their spread. These agents, including bevacizumab (Avastin), are often used in combination with chemotherapy for various cancers, such as colorectal, lung, and kidney cancer.
The Anti-VEGF Treatment Experience
Receiving anti-VEGF therapy for eye conditions involves intravitreal injections. The procedure begins with numbing eye drops or gel to minimize discomfort. The area around the eye and the eye surface are then thoroughly cleaned with an antiseptic solution to prevent infection. A small device may be used to keep the eyelids open.
The ophthalmologist then uses a very fine needle to inject the medication into the vitreous, the clear, gel-like substance that fills the eye. This injection is quick, and most patients report feeling mild pressure or minimal discomfort, comparable to a blood draw from the arm. After the injection, patients may experience some temporary irritation, redness, or a feeling of grittiness.
The frequency of these injections varies depending on the specific condition and individual patient response. Initially, treatments may be given monthly for a few months to establish control over the disease. As the condition stabilizes, the interval between injections can be extended to every few weeks or months. For cancer, anti-VEGF drugs are administered as an intravenous (IV) infusion.
Understanding Potential Side Effects
While anti-VEGF therapy is considered safe and effective, patients should be aware of potential side effects, categorized into local and systemic effects. Local side effects are related to the eye injections themselves and are more common. Patients may experience temporary eye pain or discomfort, redness, and the sensation of floaters or blurry vision immediately after the injection. These symptoms usually resolve within a day or two.
A less common but more serious local risk is infection inside the eye, known as endophthalmitis. Other rare ocular complications include increased eye pressure, retinal detachment, or hemorrhage within the eye. Systemic side effects are less common with lower doses used for eye injections, but more serious with higher doses used in cancer treatment. These can include elevated blood pressure, an increased risk of bleeding, and blood clots. Discussing all potential risks and benefits with a healthcare provider is important to make informed treatment decisions.