JUN 30, 2011
The impact of ranibizumab on AMD treatment is truly historic. Before anti-VEGF treatments, about 90 percent of patients diagnosed with neovascular AMD would become legally blind in one year. Today, some two-thirds of patients on anti-VEGFs achieve 20/40 vision. The authors of this study sought to give a real world sense of the impact ranibizumab has had in the prevention of blindness and visual impairment.
They modeled visual acuity outcomes from phase 3 trials of ranibizumab and used incidence rates of neovascular AMD from population-based studies to estimate the effects of ranibizumab among non-Hispanic whites, age 50 and older, in the United States. The researchers note that data from non-Hispanic white individuals were used because information in the literature regarding incidence rates of choroidal neovascularization in other populations is limited.
Of the 103,582 individuals developing neovascular AMD for whom ranibizumab would be indicated and available, researchers calculated that 16,268 would become legally blind in two years and 34,702 would become visually impaired. In these patients, monthly ranibizumab would reduce the incidence of legal blindness by 72 percent and the incidence of visual impairment by 37 percent, thus saving 11,784 people from legal blindness and 12,783 from visual impairment.
The authors note that this study has several assumptions and weaknesses that require one to interpret the numbers put forth as only an approximation. Among them: the incidence rates of CNV were based on a single, albeit large, study; the estimates assume BCVA measurements were made on high-contrast charts; the results assume access to monthly ranibizumab for two years; and the results are derived from a time when a person's first eye may have lost substantial vision from CNV, before monthly ranibizumab became available in 2006.