Bevacizumab, commercially known as Avastin, is a medication initially developed to treat cancer but has gained widespread use in ophthalmology for managing various retinal diseases. This article delves into the significance of Bevacizumab in treating eye conditions, focusing on its mechanism of action, clinical applications, safety profile, and potential side effects.

Bevacizumab is a monoclonal antibody that targets vascular endothelial growth factor (VEGF). By inhibiting VEGF, a protein responsible for new blood vessel formation (angiogenesis), Bevacizumab helps reduce abnormal blood vessel growth and leakage, which are central features of many retinal diseases.

While Avastin was originally developed to manage cancers such as colon and lung cancer, its off-label use in ophthalmology has transformed the treatment of vision-threatening conditions like age-related macular degeneration (AMD), diabetic retinopathy, and retinal vein occlusion.

VEGF plays a crucial role in stimulating the growth of new blood vessels in both normal and pathological processes. In retinal diseases, such as wet AMD and diabetic retinopathy, the overexpression of VEGF leads to abnormal blood vessel formation beneath or within the retina. These abnormal vessels are prone to leakage, leading to fluid accumulation, hemorrhage, and subsequent damage to the retina.

Bevacizumab binds to VEGF, preventing it from interacting with its receptors on the surface of endothelial cells (cells lining blood vessels). This action halts the process of angiogenesis and vascular leakage, ultimately stabilizing or improving vision.

Bevacizumab is utilized to treat several retinal conditions where abnormal blood vessels or fluid accumulation play a role. Key conditions include:

1. Age-Related Macular Degeneration (AMD)

• Wet AMD is a leading cause of blindness in older adults. It is characterized by the growth of abnormal blood vessels under the retina. Bevacizumab injections reduce this growth, slowing disease progression and often improving vision.

2. Diabetic Retinopathy

• In diabetic retinopathy, damaged retinal blood vessels lead to swelling, leakage, and the formation of new, fragile vessels. Bevacizumab is used to manage both diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR), helping to reduce fluid buildup and halt abnormal vessel growth.

3. Retinal Vein Occlusion (RVO)

• RVO occurs when a blockage in the retinal veins causes fluid leakage and macular edema. Bevacizumab reduces this leakage, leading to visual improvement and reduced retinal swelling.

4. Neovascular Glaucoma

• In this type of glaucoma, VEGF-driven abnormal blood vessels grow in the eye, blocking fluid drainage and raising intraocular pressure. Bevacizumab injections help reduce these abnormal vessels, preventing further complications.

In the treatment of eye diseases, Bevacizumab is administered via intravitreal injections. This involves injecting the drug directly into the vitreous humor, the gel-like substance within the eye. The procedure is typically quick and done under local anesthesia. Patients often receive multiple injections over time, depending on their response and the severity of the condition.

Ophthalmologists typically start with a loading phase, which includes monthly injections for the first few months, followed by a maintenance phase where the intervals between injections may be extended based on the patient’s progress.

Although Bevacizumab is not officially approved by the U.S. Food and Drug Administration (FDA) for ocular use, it is widely used off-label due to its efficacy and affordability. Alternative anti-VEGF agents like Ranibizumab (Lucentis) and Aflibercept (Eylea) are specifically approved for ocular conditions but tend to be more expensive. Studies have demonstrated that Bevacizumab provides comparable efficacy to these drugs in treating retinal diseases, making it a popular choice for both clinicians and patients.

Bevacizumab is generally considered safe for ophthalmic use, with most patients tolerating the drug well. However, like any medical treatment, it carries some risks and potential side effects.

Common Side Effects

• Eye discomfort: Patients may experience temporary irritation or redness following an injection.
• Floaters: Small spots or lines in the vision may occur due to the injection.
• Subconjunctival hemorrhage: A small bleed on the surface of the eye may result from the injection but usually resolves without intervention.

Rare but Serious Side Effects

• Endophthalmitis: A rare but severe infection of the inner eye, which requires urgent treatment.
• Retinal detachment: In rare cases, the injection may lead to retinal detachment, which can cause vision loss if not treated promptly.
• Increased intraocular pressure: Some patients may experience a temporary increase in eye pressure following the injection.

Systemic Risks

Although uncommon, systemic absorption of Bevacizumab could theoretically increase the risk of cardiovascular events such as stroke or heart attack, especially in older adults or individuals with preexisting conditions. However, studies have shown that the risk of such events is low when the drug is used for ophthalmic purposes.

One of the primary reasons for the widespread use of Bevacizumab in ophthalmology is its cost-effectiveness. Bevacizumab is significantly cheaper than other anti-VEGF agents like Ranibizumab and Aflibercept, making it an attractive option for both patients and healthcare providers. Its affordability has increased access to anti-VEGF therapy in low-resource settings, allowing a broader range of patients to receive sight-saving treatments.

Ongoing research aims to further understand the long-term efficacy and safety of Bevacizumab in eye care. Several clinical trials continue to evaluate its use in newer indications and compare its effectiveness with newer anti-VEGF agents.

In addition, developments in drug delivery systems, such as sustained-release implants or longer-acting formulations, may further optimize the use of Bevacizumab and other anti-VEGF agents in ophthalmology, reducing the need for frequent injections and improving patient outcomes.

Bevacizumab (Avastin) has revolutionized the treatment of retinal diseases, offering an effective and affordable solution for conditions like wet AMD, diabetic retinopathy, and retinal vein occlusion. While it is used off-label in ophthalmology, it has demonstrated comparable efficacy to more expensive alternatives, making it a vital tool in preventing vision loss worldwide.

As research continues to evolve, Bevacizumab’s role in eye care is likely to expand, offering hope to millions of patients suffering from vision-threatening conditions. Proper administration and monitoring by a qualified ophthalmologist ensure the safety and effectiveness of this powerful therapeutic agent.

By understanding the importance of Bevacizumab in ophthalmology, patients and clinicians alike can make informed decisions about treatment options that offer the potential for sight preservation and improved quality of life.

World Eye Care Foundation’s eyecare.live brings you the latest information from various industry sources and experts in eye health and vision care. Please consult with your eye care provider for more general information and specific eye conditions. We do not provide any medical advice, suggestions or recommendations in any health conditions.