Restore useful sight to people whose light-sensing retinal cells have died from retinitis pigmentosa, whatever gene caused it, by turning the retina's surviving output cells into new light sensors.
Phase 1/2 results in NEJM (Oct 2026); next trials unfunded and delayed
Updated 3d agoChecked 11 Oct1 update this week
A harmless virus (AAV2) injected into the eye's gel carries the ChrimsonR gene into retinal ganglion cells, the cells that send signals down the optic nerve.
ChrimsonR is an ion channel that opens under light, so treated cells fire when lit, standing in for the rods and cones RP destroyed.
ChrimsonR responds only to high-intensity amber light, so camera goggles detect changes in the scene and project matching light pulses onto the retina.
Patients start wearing goggles about 8 weeks after injection and train to interpret the new signal; EEG showed it reaching the visual cortex.
| Spec | GS030 optogenetic therapy |
|---|---|
| Light-sensitive protein | ChrimsonR-tdT (amber light)R (reported) |
| Delivery | AAV2, single intravitreal injectionR (reported) |
| Doses tested | 5e10, 1.5e11, 5e11 vector genomesR (reported) |
| Meaningful light-sensitivity gain | 6 of 10 participantsR (reported) |
| Improved object tasks | 4 of 8 testedR (reported) |
| Eye inflammation (early cohorts) | 70%, mostly mild, steroid-responsiveR (reported) |
R reported by the company
GenSight Biologics
Optogenetics, retinal gene therapy
GenSight Biologics is a Paris gene-therapy company listed on Euronext. Its GS030 uses optogenetics, making surviving retinal cells light-sensitive, to restore some sight in people blinded by retinitis pigmentosa.
gensight-biologics.com (opens gensight-biologics.com)Company profile →
