GenSight Biologics Provides September 2026 Business Updates

Paris, France, September 8, 2026, 7:30 am 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 provided business updates covering the summer of 2026 and confirmed the publication date for the Company’s financial statement covering the first half of 2026.

Update on Manufacturing

The manufacture of the engineering batch, which will confirm the successful transfer of the GS010/LUMEVOQ® manufacturing process to Catalent, has proceeded according to plan. The viral genome (vg) titer of the drug substance, which measures the concentration of the therapeutic gene in the drug substance, was confirmed to be within target specifications. The vg titer result in this and process development batches, along with the reproducibility of the vg titer in the upstream process, indicates that the process transferred to Catalent will have repeatable yields. The full battery of drug substance test results, demonstrating the successful transfer of the upstream stage of the process, is expected at the end of summer.

The results to date have already triggered the preparations for the manufacture of the GMP batch that will be used to sustain product supply for the Company’s early access programs.

Update on Clinical Activities

All remaining patients planned for the dose-ranging study REVISE, which is being conducted in France at the request of the French health agency ANSM, have been identified. The last treatment is scheduled for December 2026.

Following the summer break in France, during which applications for the named patient early access program (AAC) were paused, patient screening has resumed. To date, some patients have already been treated.

The first named patient early access treatment in Israel was performed in July.

Treatments under paid early access programs in other countries are expected to be carried out in the remainder of 2026.

Financial Updates

Payment for the AAC treatments after the summer break has been received.

GenSight Biologics will publish its 2026 half-year financial statement after market close on September 29, 2026, as previously announced. The quiet period that precedes the release of the financial results will begin on September 15, 2026.

Contact

GenSight Biologics
Chief Financial Officer
Jan Eryk Umiastowski
jeumiastowski@gensight-biologics.com

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 patients suffering from blinding retinal diseases. GenSight Biologics' lead product candidate, GS010 (lenadogene nolparvovec) is in Phase III in Leber Hereditary Optic Neuropathy (LHON), a rare mitochondrial disease that leads to irreversible blindness in teens and young adults. 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. 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.

Forward-Looking Statements

This press release contains forward-looking statements, including statements regarding product development prospects and financial projections. These statements do not constitute guarantees of future performance and involve risks and uncertainties. A further list and description of risks and uncertainties that could cause actual results to differ materially from those set forth in the forward-looking statements in this press release can be found in GenSight Biologics’ regulatory filings with the French Autorité des Marchés Financiers. Existing and prospective investors are cautioned not to place undue reliance on these forward-looking statements and estimates, which speak only as of the date hereof. Other than as required by applicable law, GenSight Biologics undertakes no obligation to update or revise the information contained in this press release.