OSE Immunotherapeutics : Announces Procedures for Virtual Combined General Meeting – Live Webcast Login Information

OSE Immunotherapeutics Announces Procedures for Virtual

Combined General Meeting

Live Webcast Login Information

Nantes, France, June 3, 2021, 6:00PM CET - OSE Immunotherapeutics (ISIN: FR0012127173;

Mnemo: OSE) announces the procedures for participating to the Combined General Meeting, to be held on June 24, 2021 at 2:30 p.m. CET.

As indicated in the press release dated May 19, 2021, the Combined General Meeting of June 24, 2021, will be held by live webcast, without the physical presence of shareholders or other persons usually eligible to attend pursuant to the provisions of the the order published on 25 March 2020 extended and amended by order no. 2020-1497 of 2 December 2020, decree no. 2020-418 of 10 April 2020 extended and amended by decree no. 2020-1614 of 18 December 2020 and decree no. 2021-255 of 9 March 2021.

The prior notice to the General Meeting including the agenda, the resolutions submitted for approval and the main methods of participation and voting, and also serving as notice of the meeting, was published on May 19, 2021 in the French bulletin of mandatory legal announcements (BALO).

• Login information

The General Meeting will be webcast live (in French) via a web conferencing system and shareholders of OSE Immunotherapeutics are invited to login through the link:

https://channel.royalcast.com/landingpage/oseimmunotherapeutics/20210624_1/

This link allows shareholders to register for the General Meeting as of today (and until June 24, 2021 at 2:00 p.m. CET) by entering their email address. Registrants will receive a registration confirmation in addition to the ability to add the event to their calendar.

On June 24, 2021, shareholders will be able to connect via this same link starting at 2:00 p.m. CET. The General Meeting will start at 2:30 p.m. and attendees will be able to follow the presentation by OSE Immunotherapeutics' management on their screen.

Due to the closed session and in accordance with the regulations in force, it is not possible for shareholders to amend resolutions or to propose new resolutions at the General Meeting. The shareholders retain their right to ask written questions before the General Meeting. Shareholders are invited to send their questions from today and at the latest until June 22, 2021, at 12:00 to the email address: [e-mail].A common answer can be provided to these questions as long as they present the same content. Answers to written questions will be published directly on the Company's website in the section devoted to the General Meeting / "questions and answers" and will then be deemed to have been given.

• Appointment of scrutineers

In accordance with Decree No. 2020-418, the Company's Board of Directors has decided to appoint the following shareholders as scrutineers:

• Mrs. Maryvonne Hiance, shareholder and Vice-Chairman of the Board of Directors;
• Mr. Alexis Peyroles, shareholder and CEO of the Company.

The General Meeting will be chaired by Mrs. Dominique Costantini, Chairwoman of the Board of Directors.

The Bureau thus constituted will be responsible for ensuring the proper performance of the General Meeting. It will be accompanied by CIC Market Solutions (middle office service of the issuer) which will collect and count the votes of shareholders in registered form or having voted by proxy.

• Reminder of voting procedures

To be taken into account, the duly completed and signed forms must be received no later than the second day preceding the date of the Meeting, i.e. no later than June 22, 2021.

For registered shareholders: they must return the voting form which will be sent to them with the convening notice either by post to CIC Market Solutions (Service Assemblées - 6 Avenue de Provence - 75452 Paris Cedex 09 - France), or by email to the address: [e-mail].

For bearer shareholders: they can request this voting form from the bank or financial intermediary that manages their securities, from the date of notice of meeting. Once completed and signed, the form will be returned by the shareholder along with a certificate of participation either by post to CIC Market Solutions (Service Assemblées, 6 Avenue de Provence - 75452 Paris Cedex 09) or by email to the address: [e-mail].

Shareholders are invited to regularly consult the section dedicated to the General Meeting on the Company's website:

https://ose-immuno.com/en/general-shareholders-meetings/

where they will find preparatory documents, including the voting form.

ABOUT OSE Immunotherapeutics

OSE Immunotherapeutics is an integrated biotechnology company focused on developing and partnering therapies to control the immune system for immuno-oncology and autoimmune diseases. The company's immunology research and development platform is focused on three areas: T-cell-based vaccination, Immuno- Oncology (focus on myeloid targets), Auto-immunity & Inflammation. Its balanced first-in-class clinical and preclinical portfolio has a diversified risk profile:

Vaccine platform

• Tedopi® (innovative combination of neoepitopes): the company's most advanced product; positive results for Step-1 of the Phase 3 trial (Atalante 1) in Non-Small Cell Lung Cancer post checkpoint inhibitor failure. In Phase 2 in pancreatic cancer (TEDOPaM), sponsor GERCOR
  In Phase 2 in ovary cancer (TEDOVA), sponsor ARCAGY-GINECO
  Due to the COVID-19 crisis, accrual of new patients in TEDOPaM should restart in 2021
  In Phase 2 in non-small cell lung cancer in combination with nivolumab, sponsor Italian foundation FoRT
• CoVepiT: a prophylactic second-generation vaccine against COVID-19, developed using SARS-CoV-2 optimized epitopes against multi variants. Positive preclinical and human ex vivo results in August 2020. In clinical Phase 1.

Immuno-oncology platform

• BI 765063 (OSE-172,anti-SIRPα mAb on SIRPα/CD47 pathway): developed in partnership with Boehringer Ingelheim; myeloid checkpoint inhibitor in Phase 1 in advanced solid tumors.
• CLEC-1 (novel myeloid checkpoint target): identification of mAb antagonists of CLEC-1 blocking the "Don't Eat Me" signal that increase both tumor cell phagocytosis by macrophages and antigen capture by dendritic cells.
• BiCKI®: bispecific fusion protein platform built on the key backbone component anti-PD-1(OSE-279) combined with new immunotherapy targets; 2nd generation of PD-(L)1 inhibitors to increase antitumor

efficacity.

Auto-immunity and inflammation platform

• FR104 (anti-CD28 monoclonal antibody): Licensing partnership agreement with Veloxis in the organ transplant market; ongoing Phase 1/2 in renal transplant (sponsored by the Nantes University Hospital); Phase 2-ready asset in a niche indication in autoimmune diseases.
• OSE-127/S95011 (humanized monoclonal antibody targeting IL-7 receptor): developed in partnership with Servier; positive Phase 1 results; in Phase 2 in ulcerative colitis (OSE sponsor) and an independent Phase 2a planned in Sjögren's syndrome (Servier sponsor).
• OSE-230 (ChemR23 agonist mAb): first-in-class therapeutic agent with the potential to resolve chronic

inflammation by driving affected tissues to tissue integrity.

For more information: https://ose-immuno.com/en/

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Contacts

OSE Immunotherapeutics	U.S. Media: LifeSci Communications
Sylvie Détry	Darren Opland, Ph.D.
[e-mail]	[e-mail]
[phone]	[phone]
French Media: FP2COM	U.S. and European Investors
Florence Portejoie	Chris Maggos
[e-mail]	[e-mail]
[phone]	[phone]

Forward-looking statements

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 in light of 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 15 April 2021, including the annual financial report for the fiscal year 2020, 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.