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.


OSE-279 is being evaluated in a Phase 1/2 clinical trial in patients with advanced solid tumors.

The first Phase 1/2 positive clinical results with high affinity anti-PD1 monoclonal antibody OSE-279 in advanced solid tumors were presentend at the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics, held in Boston, MA (October 11 – 15, 2023 – Abstract number 35371, Poster C063).

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 a monotherapy in advanced solid tumors. Secondary objectives include assessment of OSE-279’s antitumor activity, evaluation of the safety profile, pharmacokinetic and receptor occupancy or pharmacodynamic profile.

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