Health Topics

Avastin Injection

By Dr. Shantan Reddy

Avastin also known as bevacizumab which is an off-label, not FDA approved treatment is a full-length monoclonal antibody that binds all isoforms of VEGF-A. This drug reduces angiogenesis and vascular permeability after an intravitreal injection. Bevacizumab has been FDA approved in the treatment of metastatic colorectal carcinoma. Preliminary reports have showed promising results regarding the use of intravitreal injections of bevacizumab in the treatment of neovascular age related macular degeneration. A phase I study (SANA, Systemic Avastin for neovascular age related macular degeneration) in 15 subjects evaluated the infusion of 5mg/kg of bevacizumab in two-week intervals. A significant functional and anatomical improvement was described at a short-term follow-up (12 weeks). The only adverse event identified was a mild elevation of the systolic blood pressure. Short-term uncontrolled retrospective case series showed no apparent short-term safety concerns for intravitreal bevacizumab injections for CNV, and treated eyes had a significant decrease in macular thickness and improvement in visual acuity. Monthly bevacizumab intravitreal injections have also been tested for CNV which did not respond to other treatments (vPDT and/or  pegaptanib). Seventy-eight percent of eyes experienced an anatomical and functional benefit after treatment.  Ten rabbit eyes were injected to evaluate retinal penetration and toxicity of bevacizumab, and ERG and PEV responses were similar in injected and controlled eyes showing that bevacizumab was non-toxic to the retina of rabbits.

Finally, a randomized, multicenter, clinical trial called CATT (Comparison of ARMD Treatments Trials) included 1200 subjects and compare the efficacy and safety of bevacizumab and ranibizumab. The level of efficacy, safety, dosage, and retreatment schedule are unknown until the results of the study are revealed.  Currently, we may want to consider an off-label use of bevacizumab only because its cost is less as compared to other available anti-VEGF drugs. In summary, this off-label approach appears to have a beneficial effect in the short-term treatment of all subtypes of CNV in age related macular degeneration, but questions about its safety and long-term efficacy are still unanswered and it is advised that Lucentis be continued for improved patient safety and outcomes.

 


Topics and Subtopics: Eye Care

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