Abstract 1852: A novel PD1-CD40 bispecific antibody YH008 induces potent anti-tumor activityin vivoby PD1 dependent activation of CD40 signaling

Immunotherapies that target PD1/PDL1 pathway have marked a new era of cancer therapy. Combinatorial treatment of inhibiting PD1/PDL1 signaling and other immunomodulating agents has been widely tested and validated as a better strategy compared to single agent treatment. CD40 (TNFRSF5) is a member of the TNFR super family, a key T cell co-stimulatory signal critical for B-cell maturation and immunoglobulin class switching. Biocytogen developed a novel first in class PD1-CD40 bispecific antibody (YH008) that agonizes CD40 conditionally upon PD1 binding. In vitro study data shows YH008 can block the interaction of PD1 to PDL1 and induced dose dependent NFAT activation. YH008 was able to activate human CD40 on reporter cells in the presence of PD1-expressing jurkat cells in a dose dependent manner without relying on FcγR expressing cells. This feature is beneficial for conditionally activation of CD40+ cells in tumor microenvironment and tumor-draining lymph nodes, where tumor specific PD1+ T cells are enriched. In vivo study result shows that YH008 demonstrated robust anti-tumor efficacy against MC38 and B16F10 tumors in PD1/CD40 double humanized mice (B-hPD1/hCD40). In hCD40 mice which has no human PD1 engagement, YH008 did not show anti-tumor activity against MC38 tumor. Furthermore, YH008 did not elevate liver enzymes of MC38 bearingB-hPD1/hCD40 mice at dose as high as 26 mg/kg, demonstrating improved liver safety profile than selicrelumab. Taken together, these data demonstrated that YH008 is a promising new immunotherapeutic candidate in cancer treatment. Citation Format: Baihong Liu, Li Hui, Chonghui Liu, Zhihong Li, Fangxia Pan, Benny Yang, Qingcong Lin. A novel PD1-CD40 bispecific antibody YH008 induces potent anti-tumor activity in vivo by PD1 dependent activation of CD40 signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1852.