Sensorion Announces a Reverse Share Split of its Shares

• 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
• Publication of the reverse share split notice: July 29, 2026
• Start of the reverse share split: August 13, 2026
• Effective date of the reverse share split (listing of new shares): September 15, 2026

Regulatory News:

Sensorion (FR0012596468 – ALSEN) a pioneering clinical-stage biotechnology company specializing in the development of novel therapies to restore, treat and prevent hearing loss disorders, today announces the implementation of the reverse share split of its shares.

The reverse share split will result in the exchange of 50 existing shares of €0.10 par value (the "Existing Shares") for 1 new share of €5 par value (a "New Share").

This reverse share split is a purely technical exchange and will have no impact on the Company's share capital nor the total value of the Company’s shares held by each shareholder.

Terms of the implementation of the reverse share split

All the terms and conditions of the reverse share split were decided by the Chief Executive Officer on July 27, 2026, pursuant to the sub-delegation granted by the Board of Directors on July 23^rd, 2026, taken in accordance with the twelfth (12^th) extraordinary resolution of the General Shareholders' Meeting of May 11^th, 2026, and are detailed in the reverse share split notice published in the Bulletin des Annonces Légales Obligatoires (BALO) on July 29, 2026.

• Beginning of the reverse share split: August 13, 2026

• Effective date of the reverse share split: September 15, 2026

• Basis of the reverse share split: exchange of 50 Existing Shares with a par value of €0.10 for 1 New Share with a par value of €5 and current dividend rights.

• 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 to be issued as a result of the reverse share split: 10,312,972 shares, each with a par value of €5.

The number of New Shares resulting from the reverse share split may be adjusted in the event that holders of rights or securities giving access to the share capital exercise them outside the period of suspension of their right to exercise.

It is specified that, on July 27, 2026, the Company expressly waived the reverse share split of the necessary number of its treasury shares to obtain a whole number of shares as a result of the application of the above-mentioned exchange ratio. These shares will be cancelled upon completion of the share consolidation.

As a result of this waiver, the resources allocated to the Company’s liquidity agreement entered into with Kepler Cheuvreux on December 15, 2017 will be reduced accordingly, namely by four (4) shares, in accordance with Article 4 of AMF Decision No. 2021-01 dated June 22, 2021 renewing the implementation of liquidity agreements for equity securities as an accepted market practice, in order to reflect the reduction in the number of treasury shares resulting from the cancellation of the relevant shares.

Following the withdrawal of these resources, the position as of July 27, 2026 is as follows:

• 334,749 treasury shares;
• €38,345,37

The final number of New Shares to be issued as a result of the reverse share split will be recorded by the Company's Board of Directors or by the Chief Executive Officer at the end of the reverse share split.

• Exchange period: 30 days as from the beginning of the reverse share split (i.e. from August 13, 2026 (included) to September 14, 2026 (included)).

• Whole securities: the conversion of Existing Shares into New Shares will be carried out according to the automatic procedure (procédure d'office).

• Fractional shares: shareholders who do not hold a number of Existing Shares corresponding to a whole number of New Shares must personally purchase or sell fractional Existing Shares in order to obtain a multiple of fifty (50) until September 14, 2026 (included). After this deadline, shareholders who have not been able to obtain a number of shares in multiples of fifty (50) will be compensated by their financial intermediary during the compensation period, in accordance with articles L. 228-6-1 and R. 228-12 of the French Commercial Code and market practice.

The non-consolidated Existing Shares will be delisted at the end of the exchange period.

• Centralization: all transactions relating to the reverse share split will be operated by Uptevia, 90-110 Esplanade du Général de Gaulle 92400 Courbevoie (France), appointed as agent for the centralization of the reverse share split.

In accordance with articles L. 228-6-1 and R. 228-12 of the French Commercial Code, any New Shares that cannot be allotted individually and that correspond to fractional rights will be sold on the stock market by the account holders (teneurs de compte), and the proceeds of the sale will be allocated in proportion to the fractional rights of the holders of these rights during the compensation period.

The Existing Shares subject to the reverse share split will be admitted to trading on the Euronext Growth market in Paris under ISIN code FR0012596468, until September 14, 2026, the last day of trading.

The New Shares resulting from the reverse share split will be admitted to trading on the Euronext Growth market in Paris from September 15, 2026, the first day of trading, and will be assigned the following new ISIN code FR0012596468.

• Suspension of the exercise of rights or securities: the exercise of rights or securities conferring access to the share capital is suspended from August 14, 2026, to September 17, 2026 (included).

• 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 Obligatoires (BALO) to specify the terms of adjustment of the rights of holders of rights or securities giving access to the capital.

• Voting rights: during the exchange period referred to above, dividend rights and voting rights attached to the New Shares and Existing Shares will be proportional to their respective par value, it being specified that:

• New Shares with a par value of five euros (€5) will immediately carry voting rights (one vote per New Share);

• at the end of the exchange period, the non-consolidated shares will lose their voting rights and will no longer be included in the calculation of the quorum, and their rights to future dividends will be suspended.

Reverse share split indicative timetable

July 29, 2026	Publication of the reverse share split notice in the Bulletin des Annonces Légales Obligatoires (BALO) Publication of a notice in the Bulletin des Annonces Légales Obligatoires (BALO) announcing the suspension of the right to exercise the rights or securities conferring access to the share capital
August 13, 2026	Start of reverse share split transactions during which shareholders may sell or acquire shares to avoid fractional shares
August 14, 2026	Suspension period of the exercise of the rights or securities conferring access to the share capital
September 14, 2026	Closing of the Exchange Period
September 14, 2026	Last trading day for the Existing Shares
September 15, 2026	Effective date of the reverse share split First day of trading of the New Shares Delisting of Existing Shares
September 16, 2026	Record Date
September 17, 2026	Settlement-delivery of the New Shares End of the suspension period
September 17, 2026 to October 17, 2026	Period of compensation of shareholders with fractional rights by their financial intermediaries

About Sensorion

Sensorion is a pioneering clinical-stage biotech company, which specializes in the development of novel therapies to restore, 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 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 portfolio also comprises programs of a clinical-stage small molecule, SENS-401 (Arazasetron), for the treatment and prevention of hearing loss disorders. Sensorion’s small molecule progressed in three Phase 2 proof of concept clinical study: 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 2 study of SENS-401 was also completed in Sudden Sensorineural Hearing Loss (SSNHL) in 2022. www.sensorion.com

Label: SENSORION ISIN: FR0012596468 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.

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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