Anti-VEGF therapy targets a specific protein in the body called Vascular Endothelial Growth Factor (VEGF). The primary goal of this treatment is to prevent or reduce the harmful effects caused by abnormal blood vessel growth or leakage. By interfering with VEGF, these medications aim to stabilize or improve the health of affected tissues where uncontrolled vessel development contributes to disease progression.
The Role of VEGF in the Body
Vascular Endothelial Growth Factor (VEGF) is a signaling protein naturally produced by various cells throughout the body. Its normal function involves stimulating the formation of new blood vessels, a process known as angiogenesis, which is important for growth and healing. VEGF is involved in embryonic development, the formation of new vessels after an injury, and the growth of muscle following exercise.
However, excessive or dysregulated VEGF can lead to detrimental effects. Overproduction of VEGF can cause the growth of abnormal, fragile, and leaky blood vessels. In the eye, for instance, this can result in fluid accumulation, bleeding, and scarring beneath the retina, potentially leading to vision loss. In other parts of the body, elevated VEGF levels can contribute to increased inflammation and the progression of conditions that rely on an enhanced blood supply.
How Anti-VEGF Therapy Intervenes
Anti-VEGF therapies function by specifically blocking the activity of Vascular Endothelial Growth Factor. These medications bind directly to VEGF proteins, preventing them from attaching to their receptors on the surface of endothelial cells, which line blood vessels. This action neutralizes VEGF, stopping it from sending signals that promote abnormal blood vessel growth, leakage, or inflammation.
By inhibiting this interaction, anti-VEGF drugs reduce or prevent the formation of problematic new vessels. This stabilizes affected tissues and mitigates disease progression. This targeted approach addresses the underlying pathology without causing widespread systemic effects.
Medical Conditions Treated with Anti-VEGF Therapy
Anti-VEGF therapy is a standard treatment for several medical conditions characterized by abnormal blood vessel growth or leakage.
Eye Conditions
In ophthalmology, it is widely used for eye conditions such as wet age-related macular degeneration (AMD), a leading cause of vision loss in older adults; diabetic macular edema (DME), a complication of diabetes leading to retinal damage; and retinal vein occlusion (RVO), which causes swelling due to blocked retinal veins. Specific drugs like ranibizumab (Lucentis), aflibercept (Eylea), and faricimab (Vabysmo) are approved for these ocular indications. Bevacizumab (Avastin) is often used off-label for eye conditions.
Cancer Treatment
Anti-VEGF therapy is also an established treatment for certain types of cancer. Solid tumors require an increased blood supply to grow, and many cancers produce VEGF to stimulate new blood vessel formation (angiogenesis), enabling tumor growth and spread. By inhibiting VEGF, these therapies reduce the blood supply to tumors, slowing their growth and making them more responsive to other treatments like chemotherapy and radiation.
Bevacizumab is approved for various cancers, including metastatic colorectal cancer, certain kidney cancers, non-small cell lung cancer, ovarian cancer, and glioblastoma. Other anti-VEGF agents used in oncology include sunitinib, sorafenib, axitinib, and pazopanib, which may target VEGF receptors directly.
What to Expect with Anti-VEGF Therapy
The administration method for anti-VEGF therapy varies by medical condition.
Administration
For eye conditions, the medication is given as an intravitreal injection directly into the vitreous gel of the eye. Before the injection, the eye is numbed with anesthetic drops and cleaned to minimize discomfort and prevent infection. The injection is quick, lasting only a few seconds, and most patients report minimal pain.
For cancer treatments, anti-VEGF drugs are commonly administered as intravenous infusions. The frequency and duration of treatment vary based on the specific condition, drug, and patient response. Eye injections might occur every four to eight weeks initially, with intervals extended over time. Cancer treatments follow different schedules, often in combination with other therapies.
Potential Side Effects
Patients may experience localized side effects, especially after intravitreal injections. These can include mild and temporary eye pain or discomfort, blurred vision, or the sensation of floaters, which resolve within a day or two. Rare but more serious ocular complications include eye infection, increased eye pressure, or retinal detachment. Systemic side effects, more common with intravenous infusions for cancer, can include high blood pressure, fatigue, gastrointestinal issues, or proteinuria (excess protein in the urine). Monitoring for these effects is part of ongoing patient care.