Press release

Sensorion announces the completion of its reverse share split

• Reverse share split by the exchange of 50 existing shares with a par value of €0.10 for 1 new share with a par value of €5
• Effective date of the reverse share split (listing of new shares): September 15, 2026

Montpellier (France) and Cambridge, MA (United States), September 15, 2026, 7:30am CET – Sensorion (FR001401A9Z0 – ALSEN) (“the Company”), a pioneering clinical-stage biotechnology company specializing in the development of novel therapies to restore, treat and prevent hearing loss disorders, today announces the completion of the reverse share split of the shares composing the Company's share capital, as decided by the Chief Executive Officer on July 27th, 2026, following sub-delegation granted by the Board of Directors on July 23rd, 2026, made in accordance with the twelfth (12th) resolution of the General Shareholders' Meeting of May 11th, 2026.

Pursuant to the reverse share split, every 50 existing shares of €0.10 par value (the "Existing Shares") were exchanged for 1 new share of €5 par value (a "New Share").

Terms and conditions of the reverse share split

The main features of this reverse share split, as detailed in the notice of reverse share split published in the Bulletin des Annonces Légales Obligatoires (BALO) on July 29, 2026, the corrective notice published in the Bulletin des Annonces Légales Obligatoires (BALO) on July 31, 2026, and the press release issued by the Company on July 29, 2026, are as follows:

• Number of Existing Shares subject to the reverse share-split: 515,648,600 shares, each with a par value of €0.10.
• Number of New Shares resulting from the reverse share split: 10,312,972 shares, each with a par value of €5.

The Company waived its right to participate in the reverse share split with respect to 4 treasury Existing Shares held by it in order to allow the above-mentioned exchange ratio to be applied to a whole number of shares. Accordingly, these 4 treasury Existing Shares were cancelled upon completion of the share consolidation.

• Listing of the New Shares: the New Shares resulting from the reverse share split have been admitted to trading on the multilateral trading facility of Euronext Growth market in Paris, with effect from today, the first day of trading, and have been assigned the following new ISIN code FR001401A9Z0.

Shareholders holding a number of shares that is a multiple of 50 do not need to take any action. Their shares have been automatically consolidated by their financial intermediary.

Shareholders who were unable to obtain a number of shares that is a multiple of 50 will be compensated by their financial intermediary or Uptevia in accordance with Articles L. 228-6-1 and R. 228-12 of the French Commercial Code and market practice.

For shares held in direct registered form (nominatif pur), compensation shall be paid directly by Uptevia. For shares held in administered registered form (nominatif administré) or in bearer form (au porteur), compensation shall be paid through the shareholder's account-holding financial intermediary, which shall make the corresponding proceeds available to the shareholder within one month of the completion of the reverse stock split.

Each shareholder is invited to contact their financial intermediary with any questions on this matter.

Reverse share split timetable

Adjustment of the exercise parity of rights or securities giving access to the capital

A subsequent notice will be published in the Bulletin des Annonces Légales et Obligatoires (BALO) to specify the terms of adjustment of the rights of holders of rights or securities giving access to the capital.

About Sensorion

Sensorion is a pioneering clinical-stage biotech company, which specializes in the development of novel therapies to restore hearing, and treat and prevent hearing loss disorders, a significant global unmet medical need. Sensorion has built a unique R&D technology platform to expand its understanding of the pathophysiology and etiology of 3 inner ear related diseases, enabling it to select the best targets and mechanisms of action for drug candidates. SENS-601 (GJB2-GT) is the Company’s lead gene therapy program, targeting hearing loss related to mutations in the GJB2 gene to address important hearing loss segments in adults and children developed in the framework of its broad strategic collaboration focused on the genetics of hearing with the Institut Pasteur.

Sensorion’s pipeline also consists of a clinical-stage small molecule program, SENS-401 (Arazasetron), for the treatment and prevention of hearing loss disorders. Sensorion’s small molecule progressed in three Phase II proof of concept clinical studies: firstly, in Cisplatin-Induced Ototoxicity (CIO) for the preservation of residual hearing, with analysis completed in Q1 2026. Secondly, with partner Cochlear Limited, a study of SENS-401 for the residual hearing preservation in patients scheduled for cochlear implantation, completed in 2024. Thirdly, a Phase II study of SENS-401 was also completed in Sudden Sensorineural Hearing Loss (SSNHL) in 2022.

www.sensorion.com

Contacts

Investor Relations
Sensorion
Nicolas Bogler, Investor Relations and Communication
ir.contact@sensorion-pharma.com

Press Relations
Maarc Communication
Bruno Arabian / 00 33(0)6 87 88 47 26
bruno.arabian@maarc.fr

Label: SENSORION
ISIN: FR001401A9Z0
Mnemonic: ALSEN

Disclaimer

This press release contains certain forward-looking statements concerning Sensorion and its business. Such forward looking statements are based on assumptions that Sensorion considers to be reasonable. However, there can be no assurance that such forward-looking statements will be verified, which statements are subject to numerous risks, including the risks set forth in the 2025 full year report published on March 18, 2026, and available on our website and to the development of economic conditions, financial markets and the markets in which Sensorion operates. The forward-looking statements contained in this press release are also subject to risks not yet known to Sensorion or not currently considered material by Sensorion. The occurrence of all or part of such risks could cause actual results, financial conditions, performance or achievements of Sensorion to be materially different from such forward-looking statements. This press release and the information that it contains do not constitute an offer to sell or subscribe for, or a solicitation of an offer to purchase or subscribe for, Sensorion shares in any country. The communication of this press release in certain countries may constitute a violation of local laws and regulations. Any recipient of this press release must inform oneself of any such local restrictions and comply therewith.