Regulatory News:

GenSight Biologics ("GenSight Biologics" or the "Company") (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 the release of its half-year financial results, originally scheduled for September 19, 2025, has been postponed to September 29, 2025, after the market closes.

The postponement allows the Company’s external auditors to complete all necessary audit procedures to the highest professional standards. The Company confirms that the postponement relates only to the time required for the audit rather than to any material issues with the financial statements. The extension permits full compliance with regulatory requirements and maintains the Company’s commitment to accurate and transparent financial reporting.

The Company’s Audit Committee and Board of Directors meetings have been rescheduled accordingly:

• Audit Committee: postponed to September 24, 2025
• Board Meeting: postponed to September 26, 2025

The half-year results will be made available in the investor relations section of the Company’s website immediately following the September 29 announcement.

About GenSight Biologics S.A.

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 patients suffering from blinding retinal diseases. GenSight Biologics’ lead product candidate, GS010 (lenadogene nolparvovec)/GS010 is in Phase III 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. The product candidate GS010 is currently in clinical development, has not to date been granted marketing authorization in France or any other jurisdiction, and is therefore not available commercially.

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