Drug Approval for the Treatment of Geographic Atrophy: How We Got Here and Where We Need to Go

Abstract

PurposeTo discuss the clinical trial results leading to the FDA approval of anti-complement therapies for geographic atrophy (GA), perspectives on functional data from the GA clinical trials, and how lessons from the FDA approval may guide future directions for basic and clinical research in AMD. DesignSelected literature review with analysis and perspective MethodsWe performed a targeted review of publicly available data from the clinical trials of pegcetacoplan and avacincaptad for the treatment of GA as well as scientific literature on the natural history of GA and the genetics and basic science of complement in AMD. ResultsThe approval of pegcetacoplan and avacincaptad was based on an anatomic endpoint of a reduction in the rate of GA expansion over time. However, functional data from two phase 3 clinical trials for each drug demonstrated no visual benefit to patients in the treatment groups. Review of the genetics of AMD and the basic science of the role for complement in AMD provides only modest support for targeting complement as treatment for GA expansion, and alternative molecular targets for GA treatment are therefore discussed. Reasons for the disconnect between anatomic and functional outcomes in the clinical trials of anti-complement therapies are discussed, providing insight to guide the configuration of future clinical studies for GA. ConclusionWhile avacincaptad and pegcetacoplan are our first FDA-approved treatments for GA, results from the clinical trials failed to show any functional improvement after one and two years, respectively, calling into question whether the drugs represent a “clinically relevant outcome.” To improve the chances of more impactful therapies in the future, we: i) provide basic-science rationale for pursuing non-complement targets, ii) emphasize the importance of ongoing clinical research that more closely pins anatomic features of GA to functional outcomes, and iii) provide suggestions for clinical endpoints for future clinical trials on GA.