What we want

We believe that building a balanced portfolio of partnered and independent programs continues to be the best path forward for OSE.

We have built OSE’s strategy around two key pillars:

• Conducting high-performance research in immuno-oncology and immuno-inflammation.
• Developing multiple products in parallel, either in partnership with leading names in the pharmaceutical industry or independently depending on the indication, as appropriate.

Partnerships, especially licensing and co-development deals, provide upfront payments and milestone payments. This cash-flow allows OSE to fund its independent programs, such as Tepodi® without giving up additional equity, thus preserving shareholder value.

OSE would benefit tremendously from a pharma partnership to help finance Lusvertikimab’s late stage clinical development , as these studies in Ulcerative Colitis will involve up to 1,000 patients and entail an estimated total cost of €500 million. We can start seeking a pharma partner immediately, since the results published in early 2025 demonstrate Lusvertikimab’s effectiveness and safety in the target patient population.

As we have done for the past 12 years, we want OSE to make clear decisions based on the market potential and effectiveness of all its products, including those still in the R&D stage.

We also want OSE to communicate transparently about these decisions and the scientific results that support them.

This is essential to maintain the trust of all stakeholders — particularly current and future partners, shareholders employees, patients and the medical community.

We have a strategic disagreement with OSE’s Board of Directors.

The Board’s strategy is unclear to us, particularly regarding Lusvertikimab, with contradictory information from our perspective.

We decode the Board’s intent as being to launch — alone, without a partner — new Phase 2 studies (subcutaneous administration, maintenance therapy, or other inflammatory indications, potentially including dose-validation studies), and then move into Phase 3, still alone and without a partner.

In our view, this strategy would be incoherent and highly risky.

It would be inconsistent with the strong scientific results presented in early 2025, which already make it possible to secure an industrial partner to finance Phase 3 development.

Lusvertikimab targets ulcerative colitis — a condition for which several other treatments are being developed by other biotech companies and pharmaceutical laboratories. We therefore have a clear idea of the total cost of the necessary trials: €500 million.

This strategy would be very risky because it would force OSE to raise €500 million over several years, with an immediate need for €60–80 million.

Raising such amounts when OSE’s market capitalization is around €140 million would be extremely challenging in the current financial climate, where investors’ priorities have shifted away from biotech.

It would be impossible to raise this amount solely through equity, without even considering the severe dilution this would cause for current shareholders. This would require taking on debt from funds demanding high interest rates and asset-based guarantees.

It would also be risky because it would concentrate all of OSE’s resources on a single product, effectively putting all our eggs in one basket, and impacting our Nantes research center.

This would mean abandoning the strategy that has driven OSE’s success since its inception.

As OSE’s founding shareholders, we do not support this strategy.

On March 26, 2025, OSE published a press release presenting its 2024 results and outlining its strategy. This prompted many questions among the three of us.

We founded OSE, we know the company inside out, we collectively own 20% of its share capital, and we have known many of its Board members — in some cases, for years.

We therefore began by engaging in dialogue with the Board of Directors.

We held several meetings and exchanges in April and May, believing it would be possible to gently bring OSE back on track with the strategy that made it successful.

We proposed the appointment of three new directors to ensure our voices were heard, to reorient strategy, and to clarify communication:

• Alexis Peyroles, who from 2013 to early 2022 was one of OSE’s executives and later its CEO.
• Marc Le Bozec and Jonathan Cool, both with extensive experience in biotech development, financing, and partnerships with pharmaceutical companies.

We believed these three appointments would be sufficient.

These candidates went through the standard interview process with current Board members.

To our great surprise, the Board concluded that Alexis Peyroles and Marc Le Bozec could bring nothing to OSE. And that was not all.

On May 21, we discovered the full list of resolutions for the June General Meeting. Alongside the proposed appointment of Jonathan Cool, the Board also proposed appointing two new directors, increasing its size from nine to twelve members — further diluting Jonathan Cool’s now solitary voice.

We had to face the reality:

• The Board has no intention of listening to us.
• It has chosen the incoherent and risky strategy of conducting Lusvertikimab’s upcoming studies alone, without a partner.

We were left with only one option: to change the Board.

This was not a decision we took lightly — it was not our initial intention. On May 27, we signed a shareholders’ agreement forming a action in concert.

We sought dialogue and remain open to it. We cannot say the same for the Board:

• The Board rejected two of the three Board members we proposed — including Alexis Peyroles — on the surprising grounds that they would bring “nothing” to OSE.
• It asked for and obtained the postponement of the General Meeting from June 25 to September 30, and in the meantime initiated legal proceedings before the Nantes Commercial Court (hearing on September 8) to distort shareholder democracy and deprive us of nearly 60% of our voting rights.
• In June, Didier Hoch, Chairman of the Board, refused to meet with Markus Cappel and Jonathan Cool, two US-based nominees for director who had travelled to France to attend the General Meeting.

“The Board of Directors determines the company’s strategic direction and ensures its implementation.” – Article 22 of OSE’s bylaws.

The Board claims to value dialogue and transparency. By late May, it was clear that our meetings and exchanges had been fruitless.

We have a strategic disagreement with the current Board members, particularly regarding the clinical development of Lusvertikimab.

In our view, the Board’s strategy is incoherent and highly risky.

After 12 years serving as OSE’s CEO, Chair, and Director of Development & Strategy, we believe Lusvertikimab must move to Phase 3 and with a partner, given the estimated total cost of €500 million.

As founding shareholders holding 20% of the capital and 24% of the voting rights, our only option to bring OSE back to the strategy that made it successful is to change the Board.

Therefore, at the General Meeting to be held on September 30, we intend to remove the current Directors and to propose the same appointments of Directors as those that had been planned for the General Meeting originally scheduled for June 25.

We will only be able to file our resolutions at the end of August with the Board of Directors of OSE. We will present them here once they have been formally filed.