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| '''Ranibizumab''' (trade name '''Lucentis''') is a [[monoclonal antibody]] fragment derived from the same parent murine antibody as [[bevacizumab]] (Avastin). It is much smaller than the parent molecule and has been [[Affinity maturation|affinity matured]] to provide stronger binding to [[Vascular endothelial growth factor|VEGF]]-A. It is an [[anti-angiogenics|anti-angiogenic]] that has been approved to treat the "wet" type of age-related [[macular degeneration]] (ARMD), a common form of age-related [[vision loss]].
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| Ranibizumab was developed by [[Genentech]] and is marketed in the United States by Genentech and elsewhere by [[Novartis]] <ref>http://www.gene.com/gene/products/information/tgr/lucentis/factsheet.jsp</ref>, under the brand name Lucentis.
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| ==Mechanism of action==
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| Ranibizumab binds to and inhibits all subtypes of [[vascular endothelial growth factor]] A (VEGF-A). VEGF may trigger the growth of new vessels, which may leak blood and fluid into the eye. These leaky blood vessels may contribute to [[macular edema]] and [[choroid]]al [[neovascularization]], resulting in the wet type of ARMD.
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| By blocking VEGF-A in the eye, ranibizumab may prevent and reverse vision loss caused by wet macular degeneration.
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| ==Administration==
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| The drug is injected intravitreally (into the [[vitreous humour]] of the eye) once a month. If monthly injections are not feasible, the regimen may be reduced to 1 injection every 3 months after the first 4 months.
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| However, dosing every 3 months is linked to a loss of approximately 5 letters (1 line) in visual acuity for the following 9 months as compared with dosing on a monthly basis. Large phase 3 clinical trials (MARINA and ANCHOR) which randomized patients with wet macular degeneration showed that 95% of ranibizumab-treated patients maintained visual acuity compared with 62% of those administered placebo (P < .01) at 1 year; moreover, up to 40% demonstrated an improvement in vision of at least 3 lines. Vision maintenance and loss were defined as a loss of less than 15 letters and a gain of 15 or more letters in visual acuity, respectively, as measured using the Early Treatment of Diabetic Retinopathy eye chart.
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| ==Side effects==
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| The most common side effects in clinical trials were conjunctival hemorrhage, eye pain, vitreous [[floater]]s, increased [[intraocular pressure]], and intraocular inflammation.
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| Although there is a theoretical risk for arterial thromboembolic events in patients receiving VEGF-inhibitors by intravitreal injection, the observed incidence rate was low (< 4%) and similar to that seen in patients randomized to placebo.
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| Serious adverse events related to the injection procedure occurred with an incidence rate of less than 1% and included [[endophthalmitis]], [[retinal detachment]], and traumatic [[cataract]]s. Other serious ocular adverse events observed among ranibizumab-treated patients (incidence rate, < 2%) included intraocular inflammation and increased intraocular pressure.
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| ==External links==
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| *[http://www.earthtimes.org/articles/show/9159.html Earthtimes] article notes FDA approval in June, 2006
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| *[http://www.medicalnewstoday.com/healthnews.php?newsid=53457 Medical News Today] cites two clinical trials in [[New England Journal of Medicine]]
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| *[http://www.sciencedaily.com/upi/index.php?feed=Science&article=UPI-1-20061004-18162600-bc-us-lucentis-analysis.xml Science Daily] clarifies that although the "wet" type of macular degeneration treated by Lucentis accounts for only 10–20% of ARMD, this type causes 90% of blindness due to ARMD.
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| ==References==
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| {{reflist|2}}
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| {{Humanizedmonoclonals}}
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| [[Category:Monoclonal antibodies]]
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