Prime Editing (PE5max/PEmax) for CFH c.3643C>G (p.Arg1215Gly) in Age-related macular degeneration

Prime Editing (PE5max/PEmax) via Dual-AAV delivery is a rationale-driven therapeutic strategy for Age-related macular degeneration targeting the CFH c.3643C>G (p.Arg1215Gly) variant (Pathogenic, missense variant). The editing system (PEmax with engineered pegRNA) search-and-replace editing that directly rewrites the pathogenic transversion back to wild-type without requiring DSBs. Target tissue: Eye/Retina. Therapeutic goal: Correct CFH rs1061170 (Y402H) missense variant at chr1:196690107 to restore normal complement regulation in retina and prevent AMD progression. Risk profile: off-target Low (prime editing has inherently low off-target rate), delivery complexity Medium, immunogenicity High.

1. Molecular basis: CFH NM_000186.4(CFH):c.3643C>G (p.Arg1215Gly) is classified as Pathogenic (ClinVar variation ID 16542). Molecular consequence: missense variant. Protein change: R1215G. 2. Epidemiology: Affects approximately 200 million people worldwide, prevalence increasing to 288 million by 2040. Higher prevalence in European ancestry populations with 30-40% carrying risk allele. 3. Standard of care: Anti-VEGF therapy for wet AMD (ranibizumab, aflibercept, bevacizumab) requiring frequent injections; newly approved complement inhibitors for geographic atrophy (pegcetacoplan, avacincaptad); nutritional supplements (AREDS2). 4. Pipeline: Multiple gene therapy approaches in clinical development (AAV-based anti-VEGF delivery), CRISPR editing in Phase I/II trials for retinal disorders, complement inhibitors in Phase III for geographic atrophy. 5. Prime editing validation: PEmax (Chen et al. 2021, Cell) enables precise insertions, deletions, and all 12 point mutations without DSBs. Prime Medicine is advancing PE programs into clinical development. LNP and dual-AAV delivery of PE have been demonstrated in preclinical liver and CNS models.

1. No published data specifically correcting CFH c.3643C>G (p.Arg1215Gly) with Prime Editing (PE5max/PEmax); strategy is based on general principles and must be validated preclinically.
2. Dual-AAV delivery requires intein-mediated protein reconstitution with lower efficiency than single-AAV. Pre-existing AAV immunity in the patient population may limit eligibility.
3. Long-term durability, off-target genome-wide effects, and immunogenicity in the target patient population require thorough preclinical and clinical evaluation.