GenSight Biologics to Host Key Opinion Leader Webcasts on the Topline Results from REFLECT Phase III Clinical Trial of LUMEVOQ®

Paris, France, July 5, 2021, 6.00 pm CEST – GenSight Biologics (Euronext: SIGHT, ISIN: FR0013183985, PEA-PME eligible), a biopharma company focused on developing and commercializing innovative gene therapies for retinal neurodegenerative diseases and central nervous system disorders, today announced that it will host a Key Opinion Leader (KOL) call on Friday July 9, 2021 from 8:00 am to 9:00 am EDT / 2:00 pm to 3:00 pm CEST. The webcast will feature presentations by KOLs José-Alain Sahel, MD (University of Pittsburgh School of Medicine) and Robert Sergott, MD (Wills Eye Hospital, Philadelphia), who will discuss the Topline results from REFLECT Phase III Clinical Trial of LUMEVOQ^® in the treatment of Leber Hereditary Optic Neuropathy (LHON) that GenSight reported on June 30, 2021. Following the formal presentations, Drs. Sahel and Sergott will be joined by GenSight’s management team to answer questions.

Friday July 9, 2021 (KOL Call)

8:00 – 9:00 am EDT / 2:00 – 3:00 pm CEST

Live webcast in English: https://bit.ly/3hetAk6

Simultaneous French translation: https://bit.ly/3hetMzQ

Dial-in details:

• Paris: +33 (0) 1 7037 7166
• UK-Wide: +44 (0) 33 0551 0200
• New York: +1 212 999 6659
• When asked, indicate that you are joining the GenSight Biologics conference in English or French.

In addition, GenSight’s management team will host a second webcast on Wednesday July 7, 2021 from 8:30 am to 9:30 am CEST in French and dedicated to retail investors. Dr. José-Alain Sahel will attend and be available for questions.

Wednesday July 7, 2021 (French Retail Investors)

8:30 – 9:30 am CEST

The event will be webcast live in French at https://bit.ly/36fQ9yO.

 You will need to register in advance to get access to both webcasts. For those unable to attend the live broadcast, a recording will be accessible using the same links.

About GenSight Biologics

GenSight Biologics S.A. is a clinical-stage biopharma company focused on developing and commercializing 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 subjects suffering from blinding retinal diseases. GenSight Biologics’ lead product candidate, LUMEVOQ^® (GS010; lenadogene nolparvovec), has been submitted for marketing approval in Europe for the treatment of Leber Hereditary Optic Neuropathy (LHON), a rare mitochondrial disease affecting primarily teens and young adults that leads to irreversible blindness. 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 subjects a sustainable functional visual recovery.

About Leber Hereditary Optic Neuropathy (LHON)

Leber Hereditary Optic Neuropathy (LHON) is a rare maternally inherited mitochondrial genetic disease, characterized by the degeneration of retinal ganglion cells that results in brutal and irreversible vision loss that can lead to legal blindness, and mainly affects adolescents and young adults. LHON is associated with painless, sudden loss of central vision in the 1^st eye, with the 2^nd eye sequentially impaired. It is a symmetric disease with poor functional visual recovery. 97% of subjects have bilateral involvement at less than one year of onset of vision loss, and in 25% of cases, vision loss occurs in both eyes simultaneously. The estimated incidence of LHON is approximately 1,200-1,500 new subjects who lose their sight every year in the United States and the European Union.

About LUMEVOQ^® (GS010; lenadogene nolparvovec)

LUMEVOQ^® (GS010; lenadogene nolparvovec) targets Leber Hereditary Optic Neuropathy (LHON) by leveraging a mitochondrial targeting sequence (MTS) proprietary technology platform, arising from research conducted at the Institut de la Vision in Paris, which, when associated with the gene of interest, allows the platform to specifically address defects inside the mitochondria using an AAV vector (Adeno-Associated Virus). The gene of interest is transferred into the cell to be expressed and produces the functional protein, which will then be shuttled to the mitochondria through specific nucleotidic sequences in order to restore the missing or deficient mitochondrial function. “LUMEVOQ” was accepted as the invented name for GS010 (lenadogene nolparvovec) by the European Medicines Agency (EMA) in October 2018.

About REFLECT

REFLECT is a multi-center, randomized, double-masked, placebo-controlled study to evaluate the safety and efficacy of bilateral injections of GS010 in subjects with LHON due to the NADH dehydrogenase 4 (ND4) mutation. In the active arm, GS010 was administered as a single intravitreal injection in each eye of each subject. In the placebo arm, GS010 was administered as a single intravitreal injection to the first affected eye, while the fellow eye received a placebo injection.

 The primary endpoint for the REFLECT trial is the BCVA reported in LogMAR at 1.5 years (78 weeks) post-treatment in the second‑affected/not‑yet‑affected eye. The change from baseline in second‑affected/not‑yet‑affected eyes receiving GS010 and placebo is the primary response of interest. The secondary efficacy endpoints include: BCVA reported in LogMAR at 2 years post-treatment in the second‑affected/not‑yet‑affected eye compared to both placebo and the first‑affected eye receiving GS010, OCT and contrast sensitivity and quality of life scales.

The trial was conducted in multiple centers across Europe (1 each in France, Spain, Italy and the UK), the US (6 centers) and Taiwan (1 center). The trial planned to enroll 90 subjects with vision loss up to 1 year in duration; 98 subjects were successfully screened and treated. The first subject was treated in March 2018 and the last one in July 2019.

ClinicalTrials.gov Identifiers:

REFLECT: NCT03293524