Multifunctional Natural Killer Cell Engagers Targeting NKp46 Trigger Protective Tumor Immunity.

Over the last decade, various new therapies have been developed to promote anti-tumor immunity. Despite interesting clinical results in hematological malignancies, the development of bispecific killer-cell-engager antibody formats directed against tumor cells and stimulating anti-tumor T cell immunity has proved challenging, mostly due to toxicity problems. We report here the generation of trifunctional natural killer (NK) cell engagers (NKCEs), targeting two activating receptors, NKp46 and CD16, on NK cells and a tumor antigen on cancer cells. Trifunctional NKCEs were more potent in vitro than clinical therapeutic antibodies targeting the same tumor antigen. They had similar in vivo pharmacokinetics to full IgG antibodies and no off-target effects and efficiently controlled tumor growth in mouse models of solid and invasive tumors. Trifunctional NKCEs thus constitute a new generation of molecules for fighting cancer. VIDEO ABSTRACT.

Blocking Antibodies Targeting the CD39/CD73 Immunosuppressive Pathway Unleash Immune Responses in Combination Cancer Therapies.

Immune checkpoint inhibitors have revolutionized cancer treatment. However, many cancers are resistant to ICIs, and the targeting of additional inhibitory signals is crucial for limiting tumor evasion. The production of adenosine via the sequential activity of CD39 and CD73 ectoenzymes participates to the generation of an immunosuppressive tumor microenvironment. In order to disrupt the adenosine pathway, we generated two antibodies, IPH5201 and IPH5301, targeting human membrane-associated and soluble forms of CD39 and CD73, respectively, and efficiently blocking the hydrolysis of immunogenic ATP into immunosuppressive adenosine. These antibodies promoted antitumor immunity by stimulating dendritic cells and macrophages and by restoring the activation of T cells isolated from cancer patients. In a human CD39 knockin mouse preclinical model, IPH5201 increased the anti-tumor activity of the ATP-inducing chemotherapeutic drug oxaliplatin. These results support the use of anti-CD39 and anti-CD73 monoclonal antibodies and their combination with immune checkpoint inhibitors and chemotherapies in cancer.