AFM13 enhances the anti‐tumor activity of AB‐101 towards CD30+ tumors, conferring tumor growth control in vivo

Abstract

Introduction: Bispecific antibodies targeting CD16A and a tumor antigen have the potential to specifically redirect the cytotoxic potential of NK cells towards cancer cells through antibody-dependent cellular cytotoxicity (ADCC). It has been demonstrated that the bispecific CD16AxCD30 innate cell engager AFM13 significantly enhances the cytotoxic activity of CD16A+ NK cells towards CD30+ tumor cells. Combination of AFM13 with adoptive NK cell transfer achieved unprecedented clinical response rates in patients with relapsed/refractory (R/R) Hodgkin lymphoma (ORR 94.2% for patients treated with RP2D), while maintaining a favorable toxicity profile. AB-101 is a non-engineered, allogeneic, off-the-shelf, cryopreserved cord blood-derived NK cell product, currently being tested in a Phase 1/2 clinical trial as monotherapy and in combination with rituximab in patients with R/R B cell NHL. AB-101 is optimized for ADCC through pre-selection for the KIR-B haplotype and the natural high-affinity variant of CD16A (158V/V). In the present study, we investigated whether the combination of AFM13 with AB-101 leads to enhanced anti-tumor activity in vitro and in vivo. Methods: Cellular cytotoxic activity was assessed in 4-h calcein-release cytotoxicity assays. Cell viability, degranulation/CD107a expression and IFN-γ production were measured by flow cytometry. Tumor growth control in vivo was determined in a hematologic (Karpas-299 CD30+ T-cell lymphoma) human IL-15 NOG mouse xenograft model by whole body bioluminescence imaging. Results: We demonstrate robust, homogenous binding of AFM13 to AB-101 as assessed by flow cytometry when AB-101 cells were combined with AFM13 after thawing. Overall, the binding pattern of AFM13 was congruent to the binding pattern of high CD16A expression on AB-101, suggesting saturated loading of CD16A molecules by AFM13 on the surface of AB-101. Combination with AFM13 enhanced the cytotoxic activity of AB-101 towards CD30+ Karpas-299 tumor cells. AFM13-induced cytotoxic activity was associated with an increased functional activation status of AB-101, reflected by increased degranulation/CD107a expression and IFN-γ production in response to Karpas-299 tumor cells. Of note, viability of AB-101 cells was maintained upon exposure to AFM13 in the absence or presence of CD30+ tumor cells. Importantly, adoptive transfer of AB-101 co-administered with AFM13 conferred tumor growth control in vivo in a human IL-15 NOG mouse xenograft model. Conclusion: This study demonstrates synergistical anti-tumor activity in vivo for the combination of AFM13 and AB-101. Building on our clinical data with fresh cord blood-derived stimulated/expanded NK cells combined with AFM13 (NCT04074746), co-administration of cryopreserved AB-101 with AFM13 offers a promising highly scalable off-the-shelf immunotherapeutic treatment for patients with CD30+ malignancies. The research was funded by Affimed GmbH and Artiva Biotherapeutics Keywords: Cellular therapies, Combination Therapies, Immunotherapy Conflicts of interests pertinent to the abstract. J. Pahl Employment or leadership position: Affimed GmbH Stock ownership: Affimed GmbH T. Haneke Employment or leadership position: Affimed GmbH Stock ownership: Affimed GmbH L. Guerrettaz Employment or leadership position: Artiva Biotherapeutics S. Somanchi Employment or leadership position: Artiva Biotherapeutics H. Raymon Employment or leadership position: Artiva Biotherapeutics S. Pinto Employment or leadership position: Affimed GmbH Stock ownership: Affimed GmbH P. Flynn Employment or leadership position: Artiva Biotherapeutics J. Koch Employment or leadership position: Affimed GmbH Stock ownership: Affimed GmbH