โดย SinWiSuth » 27 พ.ย. 2010, 13:13
Bevacizumab ? Bevacizumab and ranibizumab are closely related antibodies. Ranibizumab is essentially an antibody fragment (Fab fragment) of bevacizumab with some modifications to the amino acid sequence that increase its binding of VEGF [32]. Bevacizumab is approved in the United States as an intravenous infusion for the systemic therapy of colorectal cancer.
Treatment with intravitreal bevacizumab is far less expensive than treatment with intravitreal ranibizumab ($50 compared to $1950 per injection) [33,34]. Pending results of large randomized trials, clinicians have used intravitreal injections of bevacizumab as a treatment for AMD [33-35]. Results from case series of intravitreal bevacizumab are promising. A prospective case series in 60 patients with wet AMD reported that patients who received intravitreal bevacizumab (2.5 mg, with repeated injection at one and two months if optical coherence tomography or visual acuity results indicated ongoing disease activity) had significant improvement in mean visual acuity at 12 months, retinal anatomic improvement, and no ocular or systemic side effects [36]. Submacular hemorrhage within three weeks of intravitreal bevacizumab was reported in 4 of 10 patients with large choroidal lesions (>15 mm) and in none of 34 patients in the same series who had smaller lesions [37].
Preliminary results from a randomized trial comparing intravitreal bevacizumab and ranibizumab find no difference in efficacy for the treatment of choroidal neovascularization in AMD [38]. In this single center trial, twenty patients completed six month follow-up. Visual acuity for the bevacizumab group went from baseline 31.6 letters to 46.4 letters and for the ranibizumab group from 30.4 to 37.4; the difference between the two groups was not statistically significant and the lesions in the bevacizumab group may have been somewhat more favorable at baseline.
A US federally-funded multicenter head-to-head randomized trial comparing bevacizumab and ranibizumab in 1200 patients with AMD is underway, with results expected in 2011 [34]. Systemic administration of anti-VEGF medications such as bevacizumab is also being studied in the treatment of AMD [39].
32. Steinbrook, R. The price of sight--ranibizumab, bevacizumab, and the treatment of macular degeneration. N Engl J Med 2006; 355:1409.
33. Rosenfeld, PJ. Intravitreal avastin: the low cost alternative to lucentis?. Am J Ophthalmol 2006; 142:141.
34. Epstein, P. Trials that matter: two faces of progress in the treatment of age-related macular degeneration. Ann Intern Med 2007; 146:532.
35. Chen CY; Wong TY; Heriot WJ. Intravitreal bevacizumab (Avastin) for neovascular age-related macular degeneration: a short-term study. Am J Ophthalmol. 2007 Mar;143(3):510-2. Epub 2006 Nov 13.
36. Bashshur ZF; Haddad ZA; Schakal A; Jaafar RF; Saab M; Noureddin BN. Intravitreal Bevacizumab for Treatment of Neovascular Age-related Macular Degeneration: A One-year Prospective Study. Am J Ophthalmol. 2008 Feb;145(2):249-256. Epub 2007 Dec 11.
37. Goverdhan SV; Lochhead J. Submacular haemorrhages after intravitreal bevacizumab for large occult choroidal neovascularisation in age-related macular degeneration. Br J Ophthalmol. 2008 Feb;92(2):210-2. Epub 2007 Oct 26.
38. Subramanian ML; Ness S; Abedi G; Ahmed E; Daly M; Feinberg E; Bhatia S; Patel P; Nguyen M; Houranieh A. Bevacizumab vs ranibizumab for age-related macular degeneration: early results of a prospective double-masked, randomized clinical trial. Am J Ophthalmol. 2009 Dec;148(6):875-82.e1. Epub 2009 Oct 2.
39. Moshfeghi AA; Rosenfeld PJ; Puliafito CA; Michels S; Marcus EN; Lenchus JD; Venkatraman AS. Systemic bevacizumab (Avastin) therapy for neovascular age-related macular degeneration: twenty-four-week results of an uncontrolled open-label clinical study. Ophthalmology. 2006 Nov;113(11):2002.e1-12. Epub 2006 Oct 5.
REF ::: UptoDate Online
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