NANTES, France, August 20, 2025 – 6:00pm CET - OSE Immunotherapeutics SA (ISIN: FR0012127173; Mnemo: OSE), today announced the appointment of Thomas Gidoin as Chief Financial Officer. Thomas joins the Executive Committee, bringing over 15 years of deep international expertise in capital markets, financial strategy, and governance to the company.

Thomas Gidoin is an experienced biopharma finance executive with a strong track record in strategic financial leadership, both in private and public companies. Prior to joining OSE Immunotherapeutics, he served as Chief Financial Officer at Advesya, a privately held Franco-Swiss clinical-stage biotech company in oncology and autoimmune diseases, after having spent 8 years as CFO of GenSight Biologics, a Euronext-listed French biopharma company developing gene therapies for neurodegenerative retinal diseases, where he led the company’s financing strategy from the Series B to the IPO on Euronext Paris and a number of follow-on transactions and structured financings.

Previously, Thomas was Vice President of Finance at DBV Technologies, where he led the Corporate Finance team and contributed to public offerings and private placements, including the dual listing of the company on the US NASDAQ. Prior to this, Thomas served as Northern Europe Business Controller at PregLem in London, held several positions at Ipsen, including UK Operations Controller in London and Senior Financial Analyst in the Global Operations division in Paris. He started his career in audit at Ernst & Young in Paris.

He holds master’s degrees in international finance from ESGF Paris and in international management from NEOMA Business School.

Thomas succeeds Anne-Laure Autret-Cornet, marking a new phase in the company’s financial leadership.

Nicolas Poirier, Chief Executive Officer, OSE Immunotherapeutics, commented:

“Thomas joins OSE Immunotherapeutics with deep experience in biotech capital markets financing and strategic financial planning. He has a clear understanding of what it takes to support innovation through disciplined execution and rigorous cash management. His arrival comes at a time when financial leadership is key to advancing our two late-stage assets and continuing to leverage our research platform. His expertise will further reinforce the management team to prepare the next phase of growth with clarity and focus.”

Thomas Gidoin, Chief Financial Officer, OSE Immunotherapeutics, said:

“I am thrilled to join OSE Immunotherapeutics at such a pivotal moment in its journey. With two late-stage assets in oncology and inflammation, boosted by a highly innovative research platform, the company is well positioned to create meaningful long-term value through clear multiple short-term inflexion points. I look forward to working closely with the leadership team to help unlock the full potential of OSE’s innovative pipeline.”

ABOUT OSE IMMUNOTHERAPEUTICS

OSE Immunotherapeutics is a biotech company dedicated to developing first-in-class assets in immuno-oncology (IO) and immuno-inflammation (I&I) that address the unmet patient needs of today and tomorrow. We partner with leading academic institutions and biopharmaceutical companies in our efforts to develop and bring to the market transformative medicines for people with serious diseases. OSE Immunotherapeutics is based between Nantes and Paris and is quoted on Euronext.

Additional information about OSE Immunotherapeutics assets is available on the Company’s website: www.ose-immuno.com. Follow us on LinkedIn

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This press release contains express or implied information and statements that might be deemed forward-looking information and statements in respect of OSE Immunotherapeutics. They do not constitute historical facts. These information and statements include financial projections that are based upon certain assumptions and assessments made by OSE Immunotherapeutics’ management considering its experience and its perception of historical trends, current economic and industry conditions, expected future developments and other factors they believe to be appropriate.

These forward-looking statements include statements typically using conditional and containing verbs such as “expect”, “anticipate”, “believe”, “target”, “plan”, or “estimate”, their declensions and conjugations and words of similar import. Although the OSE Immunotherapeutics management believes that the forward-looking statements and information are reasonable, the OSE Immunotherapeutics’ shareholders and other investors are cautioned that the completion of such expectations is by nature subject to various risks, known or not, and uncertainties which are difficult to predict and generally beyond the control of OSE Immunotherapeutics. These risks could cause actual results and developments to differ materially from those expressed in or implied or projected by the forward-looking statements. These risks include those discussed or identified in the public filings made by OSE Immunotherapeutics with the AMF. Such forward-looking statements are not guarantees of future performance. This press release includes only summary information and should be read with the OSE Immunotherapeutics Universal Registration Document filed with the AMF on April 30, 2025, including the annual financial report for the fiscal year 2024, available on the OSE Immunotherapeutics’ website. Other than as required by applicable law, OSE Immunotherapeutics issues this press release at the date hereof and does not undertake any obligation to update or revise the forward-looking information or statements.

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