Abstract 6281: Preclinical development of a bispecific antibody-trap selectively targeting CD47 and CD24 for cancer immunotherapy

Abstract

Abstract Limited treatment beneficial rate and market saturation of the first generation of immune checkpoint inhibitors (Such as PD-(L)1 inhibitors) have turned the attention of pharmaceutical industry to the next generation of innate immune checkpoints such as CD47/SIRPα and CD24/Siglec-10. Various cancers of lung, breast, colon, prostate, ovarian, stomach, pancreas, myeloid and lymphoid tissues are known to highly express CD47 and/or CD24, which confer cancer cells means of immune-evasion via induction of “Don’t eat me” signals. Precisely and simultaneously neutralizing CD47 and CD24 signaling on tumors, when coupled with an IgG1 antibody’s potent phagocytosis and cytotoxicity activity, may serve as potent immunotherapy for multiple cancer types. We have developed a humanized CD24 neutralizing antibody which has been revealed to neutralize CD24-Siglec-10 interaction and completely eliminate established colon cancer in syngeneic mouse models via proposed mechanisms of antibody-dependent cell cytotoxicity (ADCC), antibody-dependent cell phagocytosis (ADCP), and subsequent tumor-specific immunity as a result of macrophage activation. Using this mAb as backbone, we developed an CD24 mAb-CD47 trap by conjugating the SIRPα decoy receptor to the N-terminal of the antibody heavy chain. Initial in vitro studies indicated that this mAb-trap has simultaneous two-target binding as well as blocking activities. More promisingly, eight administrations of the mAb-trap at 3mg/kg dose in mice bearing triple-negative breast cancer resulted in a complete tumor growth inhibition. Furthermore, in a Herceptin-resistant xenograft tumor model, the mAb-trap is also efficacious and resulted in over 60% of tumor growth inhibition when administrated at 7.2mg/kg. Taken together, our data show that precise neutralization of CD47 and CD24 signaling on tumors using IgG1 antibody may serve as potent monotherapy for cancers. Citation Format: Wenzhi Tian, Song Li, Dianze Chen, Dandan Liu, Huiqin Guo, Chunmei Yang, Li Zhang, Wei Zhang, Xiaoping Tu, Liang Peng, Gui Zhao, Ruliang Zhang, Fan Zhang. Preclinical development of a bispecific antibody-trap selectively targeting CD47 and CD24 for cancer immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6281.