OSE Immunotherapeutics Announces First Patient Dosed with Anti-PD1 Monoclonal Antibody OSE-279 in a Phase 1/2 Clinical Trial in Advanced Solid Tumors or Lymphomas

Nantes, France – December 22, 2022, 7:30 a.m. CET – OSE Immunotherapeutics SA (ISIN: FR0012127173; Mnemo: OSE) announced today that the first patient has been dosed in the Phase 1/2 clinical trial evaluating OSE-279, ahigh affinity anti-PD1 blocking monoclonal antibody, in patients with advanced solid tumors or lymphomas.

This first-in-human open label Phase 1/2 dose escalation and expansion study aims to determine the Maximum Tolerated Dose and/or the recommended Phase 2 dose of OSE-279 as amonotherapy in advanced solid tumors or lymphomas. Secondary objectives include assessment of OSE-279’santitumor activity, evaluation of the safety profile, pharmacokinetic and receptor occupancy or pharmacodynamic profile.

OSE-279 is a high affinity humanized anti-PD1 monoclonal antibody blocking both PD-L1 and PD-L2, the ligands of PD1 overexpressed by tumor cells and tumor microenvironment. Overexpression of PD-L1 and PD-L2 on tumor cells and other cell types of the tumor microenvironment is a mechanism of tumor immune escape. 

OSE-279 is the key anti-PD-1 backbone component of OSE’s bifunctional checkpoint inhibitor BiCKI® platform that is targeting PD1 and other new immune targets. The first cytokine selected to be paired with the anti-PD1 in the bispecific antibody is Interleukin-7 (IL-7), which has been shown at preclinical stage to improve long-term immune functions and cancer immunotherapy efficacy. BiCKI®-IL-7 has potential to address the needs of a patient population in immune escape from checkpoint inhibitor treatment.

Nicolas Poirier, Chief Executive Officer of OSE Immunotherapeutics, comments: “We are very excited to begin first-in-human testing with our proprietary high affinity anti-PD1 monoclonal antibody, which is covered by a strong global patent portfolio in the US, Europe, Asia and South America. Dosing of the first patient marks a significant milestone in the development of OSE-279, and we look forward to the first results assessing the therapeutic potential of OSE-279 as a monotherapy treatment. Further internal clinical development of OSE-279 as a monotherapy would be conducted in pre-identified cancer niche indications to address patients with high unmet medical needs despite immuno-sensitive tumor type. This first clinical study will also allow us to later explore OSE-279, the backbone of OSE’s BiCKI® platform, in combination with other OSE drug candidates or with external assets accessed through potentialnew partnerships with biotech or pharmaceutical companies.”

Given the advantages of owning a proprietary and protected anti-PD1 antagonist antibody in the new era of immuno-oncology, OSE Immunotherapeutics has developed a global intellectual property strategy protecting OSE-279 until at least 2039. This has been achieved through the grant in 2022 of patents for the US, Europe, China, Japan, Korea, Australia and Mexico to date. These patents protect the antibody sequences of OSE-279 associated with its innovative biological and manufacturing properties.