December 20, 2016

GenSight Biologics reports sustained visual acuity gain at 78 weeks in its Phase I/II Study with GS010 for the treatment of Leber’s Hereditary Optic Neuropathy (LHON)

• Confirmation of the good safety and tolerability profile of GS010
• Sustained improvement of visual acuity in patients with vision loss for less than 2 years

Paris, France, 20 December 2016 – GenSight Biologics (Euronext: SIGHT, ISIN: FR0013183985, PEAPME
eligible), a biopharma company that discovers and develops innovative gene therapies for
neurodegenerative retinal diseases and diseases of the central nervous system, today reported additional
promising results after 78 weeks of follow-up in its Phase I/II clinical trial. These results confirm the
favorable safety and tolerability profile of GS010, while demonstrating sustainable visual acuity
improvement in patients with Leber’s Hereditary Optic Neuropathy (LHON).

Source: Gensight