M0324的抗肿瘤活性和安全性的临床前验证，一种新型MUC-1条件性CD40激动剂，及其与免疫检查点抑制剂（ICI）联合以实现选择性免疫激活

Background: MUC-1, a glycoprotein commonly overexpressed in various cancers, plays a pivotal role in tumor progression and immune evasion. M0324 is a novel MUC-1-conditional CD40 agonist designed to activate antigen-presenting cells in the presence of MUC-1-overexpressing tumor cells. Targeted CD40 activation could minimize systemic toxicity observed with first‑generation unconditional CD40 antibodies. Methods: The effect of M0324 on the activation of CD40 expressed on human dendritic cells (DCs) was assessed in vitro and benchmarked against anti-CD40 antibodies, using MUC-1 expressing HCC827 tumor cell line co-cultured with primary human monocyte-derived DCs. Co-culture of human primary B cells with human tumor cell lines with various MUC-1 expression was analyzed to further characterize MUC-1 dependent M0324 activity. In vivo efficacy was evaluated using M0324m, a mouse surrogate for M0324, as monotherapy or in combination with anti-PD-L1, in hMUC-1 expressing tumor models. Results: In vitro , M0324 significantly enhanced DC activation in the presence of MUC-1 expressing tumor cells; no activity was observed in the absence of MUC-1 expressing cells. M0324 led to higher activation of IL‑12p40 expression in DC HCC827 tumor cell co-cultures versus other agonistic anti‑CD40 antibodies. Co-culture of human primary B cells with tumor cell lines with various levels of MUC-1 expression demonstrated that M0324-induced B cell activation was linked to MUC-1 expression levels on tumor cells. In vivo , a single dose of M0324m demonstrated robust tumor eradication in hMUC-1 high immune competent mouse tumor models (orthotopic Panc02-MUC-1 model: 93%; MC38-MUC-1 model: 100% tumor-free mice). The lack of body weight loss in mice after M0324m dosing indicated minimal off-tumor effects and increased therapeutic index due to the conditional activation of CD40 in the presence of MUC‑1. In contrast, anti-mouse CD40 benchmark antibody induced body weight loss, and its marginally tolerable dose failed to control tumor growth. M0324m also demonstrated robust antitumor activity in hMUC-1 int tumor models (MC38, 4T1). Combination of M0324m with anti-PD-L1 in hMUC-1 int tumor model further improved tumor growth inhibition. Conclusions: M0324 was shown to selectively activate DC and B cells only in the presence of MUC-1 expressing tumor cells, demonstrating superior in vitro and in vivo activity compared to anti-CD40 agonistic antibodies. M0324m further improved tumor control when combined with anti-PD-L1. M0324m was also well-tolerated in vivo . Overall, the preclinical data suggest that combination of M0324 with ICIs may maximize the rigor of de novo or pre-existing T cell responses. A Phase 1 study of M0324 as monotherapy and in combination with pembrolizumab and chemotherapy is ongoing (NCT07166601).