GenSight Biologics S.A.

Capital/Financing Update • Jan 23, 2019

Press Release

GenSight Biologics Reports its Cash Position as of December 31, 2018

Paris, France, January 23, 2019, 7.30 am CET – GenSight Biologics (Euronext: SIGHT, ISIN: FR0013183985, PEA-PME eligible), a biopharma company focused on discovering and developing innovative gene therapies for retinal neurodegenerative diseases and central nervous system disorders, today reported its cash position as of December 31, 2018.

Cash and cash equivalents

GenSight Biologics' cash and cash equivalents was €26.2 million as of December 31, 2018, compared to €39.2 million as of September 30, 2018.

The acceleration of cash burn in the last quarter of 2018 principally reflects the final steps of pharmaceutical development for GS010, in preparation for a marketing authorization filing in Europe. This filing is expected in the last quarter of 2019.

Number of outstanding shares

As of December 31, 2018, GenSight Biologics' number of outstanding shares was 24,802,973 ordinary shares.

GenSight Biologics will report its cash position as of March 31, 2019 on April 23, 2019.

Contacts

GenSight Biologics Thomas Gidoin Chief Financial Officer tgidoin@gensight-biologics.com +33 (0)1 76 21 72 20

RooneyPartners Media Relations Marion Janic mjanic@rooneyco.com +1-212-223-4017

The Trout Group US Investor Relations Chad Rubin crubin@troutgroup.com +1-646-378-2947

James Palmer Europe Investor Relations j.palmer@orpheonfinance.com +33 7 60 92 77 74

About GenSight Biologics

GenSight Biologics S.A. is a clinical-stage biopharma company focused on discovering and developing innovative gene therapies for retinal neurodegenerative diseases and central nervous system disorders. GenSight Biologics' pipeline leverages two core technology platforms, the Mitochondrial Targeting Sequence (MTS) and optogenetics to help preserve or restore vision in patients suffering from blinding retinal diseases. GenSight Biologics' lead product candidate, GS010, is in Phase III trials in Leber Hereditary Optic Neuropathy (LHON), a rare mitochondrial disease that leads to irreversible blindness in teens and young adults. Using its gene therapy-based approach, GenSight Biologics' product candidates are designed to be administered in a single treatment to each eye by intravitreal injection to offer patients a sustainable functional visual recovery.