HMR-59 (AAVCAGsCD59 / JNJ-1887): An Investigational Gene Therapy for Age-Related Macular Degeneration

1. Executive Summary

HMR-59, also identified by the codenames AAVCAGsCD59 and JNJ-1887, represents an investigational gene therapy employing an adeno-associated virus serotype 2 (AAV2) vector. It is designed as a potential one-time intravitreal treatment for advanced forms of Age-Related Macular Degeneration (AMD), including Geographic Atrophy (GA) and neovascular (wet) AMD.[1] The therapeutic strategy is centered on the intraocular expression of a soluble form of the human CD59 protein (sCD59). This protein is a natural inhibitor of the terminal complement pathway, specifically targeting the Membrane Attack Complex (MAC), a key mediator of cellular damage in AMD. By augmenting local sCD59 levels, HMR-59 aims to protect retinal cells from complement-mediated destruction, thereby slowing disease progression.[2]

The therapy was initially developed by Hemera Biosciences [1] and subsequently acquired by Janssen Pharmaceuticals, a Johnson & Johnson company, in December 2020, after which it also became known as JNJ-1887 or JNJ-81201887.[7] HMR-59 has completed Phase 1 clinical trials for both GA (NCT03144999) and wet AMD (NCT03585556). These early-phase studies established a manageable safety profile, with ocular inflammation being the most notable adverse event, generally mild to moderate and responsive to steroid treatment. Preliminary efficacy signals, such as a potential reduction in GA lesion growth rate and a decreased need for anti-VEGF injections in wet AMD, were also observed.[1]