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A.R. Shah, L.V. Del Priore; Comparing Efficacy of AMD Treatments Using Lineweaver–Burke Plots: A Meta Analysis . Invest. Ophthalmol. Vis. Sci. 2006;47(13):2190.
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Multiple pharmacological treatments [photodynamic therapy (PDT), Macugen, Lucentis, and Anecortave Acetate (AA)] exist for exudative AMD; typically these treatments are compared to controls in clinical trials but not to one another. Post–hoc treatment comparisons are difficult due to differences in time of entry into clinical trials and differences in the initial visual acuity score (VAS) in clinical trials; however, we have shown the rate of visual loss in untreated eyes is linear on a double reciprocal Lineweaver–Burke (LB) plot with a high correlation coefficient (0.952) after the adjustments are made for these parameters. Herein we use LB plots to compare the efficacy of different AMD treatments to one another.
Visual acuity data from four pharmacological treatments were plotted on LB plots against cumulative control data. Best fit lines were determined for the cumulative control data and each pharmacological treatment. Vertical translations were performed to determine the likely outcome if all treatments were initiated at the same visual acuity.
Macugen, PDT and AA all produce a similar change in line slope on a LB plot, indicating their efficacy is similar if adjustments are made for differences in initial VAS and timing of intervention; Lucentis appears to be the most efficacious treatment. For example, if all treatments are started at an initial VAS of 60 letters (Bailey–Lovie) we would expect the final VAS for Lucentis (69.0 letters) to be better than eyes treated with Macugen (48.7 letters), PDT (39.6 letters), AA (41.8 letters) or without treatment (9.8 letters). Treatment is not beneficial if it is started too late; the starting initial VAS after which treatment will not improve for PDT (22.1 letters), Macugen (18.4 letters), and AA (21.3 letters) are similar.
Despite limited published data it would appear that Lucentis is the most effective treatment for exudative AMD since it is the only treatment that reverses the slope of visual acuity loss on a LB plot; clinically, this corresponds to the fact that this is the only treatment proven to increase visual acuity in a significant subset of patients. Macugen, PDT and AA achieve similar final visual acuities if adjustments are made for initial visual acuity and timing of intervention.
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