EGFRxCD16 bispecific antibodies orchestrate superior NK cell-mediated lysis of ovarian cancer and NSCLC cell lines in combination with oncolytic viruses

Combination therapy integrating bispecific antibody (BsAb) and oncolytic viruses (OVs) to enhance antitumor immune response offers a promising therapeutic approach in comparison with OV treatment alone. This study aims to strengthen and characterize NK cell-mediated antitumor responses using modified oncolytic viruses, i.e., ONCOS-102 and ONCOS-204 genetically engineered to express Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) and the ligand of inducible T-cell co-stimulator (ICOSL), respectively, in combination with a BsAb targeting CD16 and the epidermal growth factor receptor (EGFR). Changes in phenotype, degranulation, cytokine production, and cytotoxicity of NK cells induced by combined treatment were compared with those induced by individual treatment strategies against non-small cell lung cancer, malignant melanoma, and ovarian cancer. Using flow cytometry and colorimetry-based cytotoxic assays, our results showed that EGFRxCD16 BsAb was the main variable in driving NK cells toward an activated phenotype and enhanced NK function; while the OVs alone did not demonstrate drastic impact on NK cells. Interestingly, tumor preconditioning with OVs in combination with EGFRxCD16 BsAb showed the most potent NK cytotoxicity in comparison with EGFRxCD16 BsAb alone and appeared to synergize best against ovarian and EGFRmut lung tumor cell lines. Despite differences between tumor types, our data suggest a favorable interplay between OVs, especially ONCOS-102, and EGFRxCD16 BsAb in sensitizing NK cell antitumor response in vitro. These results warrant further in vivo exploration and clinical translation of this promising combination of therapeutic modalities.