Affimed N.V. (Nasdaq: AFMD), a clinical-stage immuno-oncology company committed to giving patients back their innate ability to fight cancer, today announced that three posters with preclinical data of its innate cell engagers (ICE®) are presented at the 36th Annual Meeting of the Society for Immunotherapy of Cancer (SITC). The data highlight Affimed’s preclinical initiatives to further elucidate the mechanisms of action for its lead ICE® candidates AFM13 and AFM24, providing evidence that both ICE® molecules increased the number of NK cells which functioned as serial killers against cancer as well as the role of macrophages in the anti-tumor activity of AFM24.

The poster based on abstract 894 displays data generated through a collaboration with Prof. Björn Önfelt’s group at the Karolinska Institutet, Stockholm. In the study, microchip technology was used for two ICE® drug candidates, AFM13 and AFM24, at single cell resolution to better understand their mode of action. Both ICE® molecules enhanced NK cell cytotoxicity and increased the number of serial killers, i.e. NK cells which kill a number of tumor cells sequentially. Shedding inhibition of the innate immune cell surface protein CD16 resulted in the maintained cytotoxic effect of either ICE® molecule demonstrating that stabilization of CD16 is not required for effective tumor cell killing by ICE® drug candidates.

“Showing serial killing for AFM13- and AFM24-engaged NK cells in single cell resolution is impressive,” said Prof. Björn Önfelt. “The microchip technology visualizes the cytotoxicity of AFM13- and AFM24-engaged NK cells and demonstrates that ICE® activated NK cells can lead to multiple tumor cell killings by a single NK cell.”

Two additional posters (abstracts 880 and 881) present data on AFM24’s ability to induce antibody dependent cellular phagocytosis (ADCP). AFM24, the bispecific ICE® targeting EGFR and CD16A, led to enhanced macrophage-mediated ADCP on various EGFR-expressing tumor cell lines, irrespective of their EGFR-pathway mutational status.

To refine the prediction of in vivo tumor responses to AFM24, Affimed has established 2D and 3D assay conditions in patient-derived xenograft (PDX) cell lines. The 3D model is designed to replicate intrinsic physiological conditions. Early results show that AFM24 can induce ADCP in tumor cells in 2D PDX cell cultures, engaging M0, M1 and M2 macrophage subsets context-dependently. ADCP is potentially instrumental for AFM24’s mechanism of action, especially in macrophage-rich tumors.

“Our ICE® AFM24 is in development for a number of solid tumor indications,” said Dr. Arndt Schottelius, CSO of Affimed. “Considering that many solid tumors are rich in macrophages, it is very encouraging to see what role ADCP plays in its mechanism of action. The newly established 2D and 3D models will help to predict responses to AFM24 in certain tumor types.”

AFM24 is currently investigated as monotherapy in a Phase 1/2a study in patients with EGFR-expressing solid tumors in need of alternative treatment options. In addition, Affimed and NKGen Biotech have initiated a clinical study to investigate AFM24 in combination with NK cells. Affimed expects to initiate an additional clinical study with an anti-PD-L1 checkpoint inhibitor before the end of 2021.