Reaction of the Three Founding and Concerted Shareholdersto the Latest Announcements from OSE Immunotherapeutics

[Download the presse release]

Dominique Costantini, Emile Loria and Alexis Peyroles, founding shareholders and executives of OSE Immunotherapeutics (OSE) from 2012 to 2024, express their surprise at the press release published this morning by OSE and state their strong opposition to its content.

This release wrongly conveys the impression that “ongoing discussions with concertist shareholders” would lead to a “strategic alignment” and to a “governance evolution”.

The three founding shareholders entered into an action in concert on May 27 because:

• they believe in the long-term potential of OSE’s entire portfolio, of the three ongoing partnerships, and of its two most advanced assets, Tedopi® and Lusvertikimab;
• they are in disagreement with the Board of Directors regarding strategy, in particular concerning the clinical development of Lusvertikimab;
• they reject any reckless, dilutive and risky headlong rush that would compel OSE to raise €500 million over several years and to concentrate all its resources on a single product;
• the positive Phase 2 results already achieved, together with the unique mechanism of action of Lusvertikimab are highly promising for patients suffering from ulcerative colitis;
• these results enable the establishment of a major pharmaceutical partnership to launch the late-stage clinical development of Lusvertikimab.

In today’s press release from OSE, they read nothing that could resolve the strategic disagreement. On the contrary, they see confirmation of their concerns regarding the strategy pushed by the Board of Directors.

After unsuccessful attempts at dialogue, the three founding shareholders confirm that a change of the Board of Directors is necessary in order to change OSE’s strategy. The governance changes proposed in OSE’s press release today are, in fact, insufficient to consider any real change of strategy.

Dominique Costantini, Emile Loria and Alexis Peyroles will shortly make public the resolutions they will present at the General Assembly on September 30, 2025. In the meantime, they invite all OSE stakeholders to consult the website ose-immuno-ensemble.com, which they have created ahead of this General Assembly that will be decisive for the company’s strategy.

Press contact: Séverine Besse-Le Saux – severine@mrsbesse.com, +33 6 22 59 13 71