This review by Dalkara and Sahel (Comptes Rendus Biologies, 2014) synthesizes the state of retinal gene therapy around the pivotal LCA2 (RPE65) clinical trials. The authors report that subretinal AAV2-RPE65 delivery was safe with sustained visual improvement across four active phase 1 trials (NCT00749957, NCT01496040, NCT00516477, NCT01208389), with the greatest gains in children who achieved ambulatory vision . The foundational phase 1 data underlying this claim come from three adults receiving AAV2.hRPE65v2, showing logMAR acuity improvements of 0.28β1.04 over six months with no systemic immune responses .
The review's most prescient claims were subsequently validated. Its caution that disease progression continues despite gene replacement was borne out in 5-year follow-up showing variable adult outcomes and continued degeneration concerns , and its readministration-safety prediction was confirmed in a dedicated contralateral-eye phase 1 trial . The phase 3 voretigene neparvovec trial (mean MLMT change 1.8 vs 0.2 light levels) later converted the review's proof-of-concept framing into clinical practice .
As a narrative review (not systematic), it carries stated weaknesses: reliance on early-phase, small-sample trials (the foundational trial had n=3, uncontrolled, unmasked, 6-month follow-up ), cross-species translational gaps (mouse-to-primate AAV transduction failures), and undisclosed-until-end conflicts of interest β both authors consult for GenSight Biologics and Sahel founded Pixium Vision, relevant since the review champions RdCVF and optogenetic strategies they were commercializing . The rd1 mouse story also warns that background mutations (Gpr179) can mask rescue in preclinical models the review leaned on . What would change the verdict: replicated failure of voretigene durability, adverse events on long-term follow-up, or failure of RdCVF/optogenetic translation β the 2025 cortical-dominance study suggesting limited BCVA gains adds nuance but does not overturn the core claims .
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