ER-100 OSK gene therapy enters first-in-human glaucoma trial on June 9

Lu’s 2020 Nature paper demonstrated that doxycycline-inducible OSK expression regenerated crushed optic-nerve axons in aged mice and restored visual evoked potentials within 16 days. The same construct, minimally altered, reached the clinic six years later. The mouse data showed axon regrowth quantified by CTB tracing and behavioral recovery on optomotor assays; no equivalent functional endpoints have yet been reported in humans.

The original coverage understates persistent toxicity. Lu’s later work established that OSK remains cytotoxic in multiple non-neuronal cell types when expression exceeds 14 days, a constraint that drove the choice of the eye as the first target. No public data address off-target methylation changes outside the retina or long-term oncogenic risk after repeated dosing.

Operationally, the trial tests a single intravitreal dose in patients with advanced glaucoma. Success requires measurable improvement in visual-field sensitivity or retinal nerve-fiber-layer thickness by month six. Failure would narrow reprogramming’s near-term clinical path to ocular indications only.

Altman’s 2023 follow-up in Cell Reports confirmed that OSK resets methylation clocks in retinal ganglion cells without full pluripotency. This supports the narrow therapeutic window but also shows incomplete restoration of youthful transcriptomes after 30 days, indicating additional factors will be required for durable effect.