Update on Information Relating to the General Meeting of September 30, 2025 61 Founding, Historical, Employee and Executive Shareholders of the Company, Representing Approximately 20.1% of Voting Rights have entered into a Shareholders’ Agreement NANTES, France – September 12, 2025, 8:00 a.m. – OSE Immunotherapeutics SA (ISIN: FR0012127173; Mnemo: OSE) has been informed of the execution, on September 11, 2025, of a shareholders’ agreement (the “Agreement”) between 61 founding, historical, emp