OSE Immunotherapeutics

Regulatory Filings • May 2, 2022

OSE Immunotherapeutics Announces New European Patent Granted Covering CLEC-1, Novel Myeloid Immune Checkpoint Target For Cancer Immunotherapy

• A new protection covering CLEC-1 antagonists until 2037
• Patent also granted in Japan and notice of allowance granted in the US

Nantes, France – May 2, 2022, 7:30am CET – OSE Immunotherapeutics SA (ISIN: FR0012127173; Mnemo: OSE) today announced the grant of a new patent from the European Patent Office (EPO) strengthening the protection covering its novel myeloid cell immune checkpoint target, CLEC-1 (a C-type lectin receptor), and its use in cancer treatment. This patent provides a protection until 2037.

CLEC-1 is a C-type lectin receptor with demonstrated potential to inhibit the functions of myeloid cells and to block anti-tumor responsiveness of T-lymphocytes. Myeloid cells have the ability to accumulate in the tumor microenvironment and deregulate the immune activation of T-lymphocytes. CLEC-1 is a new therapeutic target of interest in immuno-oncology.

Dominique Costantini, Chief Executive Officer of OSE Immunotherapeutics, comments: "This European patent is a major step that provides products targeting CLEC-1 a strong intellectual property and a broad scope as it notably covers the use of antagonist antibodies targeting CLEC-1 in cancer treatment. The patent has been extended to other major territories with the notice of allowance already granted in the United States and the patent granted in Japan."

Nicolas Poirier, Chief Scientific Officer of OSE Immunotherapeutics adds: "Based on our fruitful collaboration with the CR2TI research team*, we now have preclinical results identifying CLEC-1 and its antagonists as an innovative immunotherapy that releases the brakes on macrophage phagocytosis and dendritic cells antigen presentation and demonstrates synergistic anti-cancer effects, in particular when combined with chemotherapy. The latest preclinical efficacy data open the pathway for the development of monoclonal antagonist antibodies targeting new myeloid checkpoint inhibitor target CLEC-1, and for future translational clinical development of an innovative cancer immunotherapy."

*Collaborative program between OSE Immunotherapeutics and Dr Elise Chiffoleau's (https://cr2ti.univnantes.fr/research/team-1) research teams (Center for Research in Transplantation and Translational Immunology (CR2TI), UMR1064, INSERM, Nantes University at Nantes University Hospital).

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 Immuno-Inflammation. Its balanced first-in-class clinical and preclinical portfolio has a diversified risk profile:

Immuno-Oncology first-in-class products

• Tedopi® (innovative neoepitope combination): the Company's most advanced product; positive results for Phase 3 trial (Atalante 1) in Non-Small Cell Lung Cancer patients in secondary resistance after checkpoint inhibitor failure.
• Other ongoing combination trials sponsored by cooperative clinical research groups in oncology:

Phase 2 in pancreatic cancer (TEDOPaM), sponsor GERCOR.

Phase 2 in ovary cancer, in combination with pembrolizumab (TEDOVA), sponsor ARCAGY-GINECO.

Phase 2 in non-small cell lung cancer in combination with nivolumab, sponsor Italian foundation FoRT.

• BI 765063 (OSE-172, anti-SIRPα mAb on CD47/SIRPα pathway): developed in partnership with Boehringer Ingelheim in advanced solid tumors; positive Phase 1 dose escalation results of BI 765063 in monotherapy and in combination with ezabenlimab (PD-1 antagonist); ongoing expansion Phase 1.
• OSE-279, anti-PD1 advanced preclinical stage.
• BiCKI®: bispecific fusion protein platform built on the key backbone component of anti-PD1 combined with a new immunotherapy target (for example: BiCKI®-IL7, preclinical stage) to increase anti-tumor efficacy.

Immuno-Inflammation first-in-class products

• OSE-127/S95011 (humanized monoclonal antibody antagonist of IL-7 receptor): developed in partnership with Servier; positive Phase 1 results; ongoing Phase 2 in ulcerative colitis (sponsor OSE) and ongoing Phase 2a in Sjögren's syndrome (sponsor Servier).
• FR104 (anti-CD28 monoclonal antibody): licensing partnership agreement with Veloxis Pharmaceuticals, Inc. in transplantation; ongoing Phase 1/2 in renal transplant (sponsored by the Nantes University Hospital); US IND obtained by Veloxis Pharmaceuticals, Inc. for a clinical trial; Phase 2 planned in an autoimmune disease indication.
• OSE-230 (ChemR23 agonist mAb): preclinical stage therapeutic agent with the potential to resolve chronic inflammation by driving affected tissues to tissue integrity.

CoVepiT: a prophylactic second-generation vaccine activating cytotoxic T lymphocytes against COVID-19, developed using optimized epitopes from SARS-CoV2 viral proteins, epitopes non impacted by multi-variants. Shows good tolerance and very good level of T cell immune response. In clinical testing, a long-term memory response was confirmed at 6 months.

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

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Contacts OSE Immunotherapeutics Sylvie Détry sylvie.detry@ose-immuno.com +33 153 198 757

Investor Relations Thomas Guillot thomas.guillot@ose-immuno.com +33 607 380 431

Media U.S. Media: LifeSci Communications Darren Opland, Ph.D. darren@lifescicomms.com +1 646 627 8387

French Media: FP2COM Florence Portejoie fportejoie@fp2com.fr +33 607 768 283

Guillaume van Renterghem – LifeSci Advisors gvanrenterghem@lifesciadvisors.com +41 76 735 01 31

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 forwardlooking 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 2022, including the annual financial report for the fiscal year 2021, 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 forwardlooking information or statements.