Abstract 3432: A novel anti-CLDN6-CD137 bispecific antibody (NBL-028) for treating Claudin 6 positive solid tumors

Abstract

Abstract Claudin-6 is a tetraspan membrane protein associated with tight junction formation. Its expression in normal tissues is restricted to the fetal organs but is not detected in the adult tissues. Increased expression of CLDN6 has been shown in several human malignancies such as testicular, ovarian, uterine, liver and lung adenocarcinoma, and is associated with poor prognosis in these cancer patients. Therefore, CLDN6 is a promising tumor-associated antigen (TAA) for tumor-targeting therapeutics such as CART and T cell engaging bispecific antibodies. CD137 co-stimulation has been reported to lead to extended T-cell proliferation, reactivating anergic T cells, promoting memory T cell formation and maintenance. Activating CD137 with agonistic antibodies presents a great opportunity to improve the therapeutic efficacy of immune checkpoint inhibitors (ICIs) or overcome resistance to ICIs. Additionally, a bispecific antibody that activates CD137 signaling only in the presence of TAA would help reduce the dose-dependent hepatotoxicity that was observed in clinical trials with monoclonal anti-CD137 agonistic antibody due to the activation of CD137 signaling in liver resident Kupffer cells. NBL-028 is a novel tetravalent bispecific antibody uniquely designed to activate the CD137 co-stimulatory pathway in the tumor microenvironment through the CLDN6-mediated clustering of CD137. NBL-028 binds to Claudin 6 with high affinity and specificity, activates CD137 in a CLDN6-dependent manner with fast-on and fast-off CD137 binding properties. NBL-028 demonstrated strong CLDN6-dependent T-cell activation and T-cell mediated cytotoxicity in vitro. NBL-028 elicits potent anti-tumor effects and immunological memory in mouse models without detectable liver damages or systemic toxicity. The tumor infiltrated Lymphocyte (TIL) analysis also demonstrated that NBL-028 treatment induced CD45+ immune cells infiltration, decreased Treg/CD8 ratio and increased M1/M2 like macrophage ratio. Furthermore, NBL-028 is designed upon a proprietary molecular scaffold with superior developability features, demonstrated by stability, yield and ease to purify. NBL-028 is currently at the stage of IND-enabling activities with the aim to enter clinical studies for treating Claudin 6 positive solid tumors in 1Q 2023. Citation Format: Raymond Yu, Yong Tong, Huarui Lu, Makenzie Danton, Samantha Dillman, Joshua Dewe, Joshua Karchin, Samruddhi Patil, Danielle Lavery, Haichun Huang, James Pei, Zhong Liu, Han Li, Ming Lei. A novel anti-CLDN6-CD137 bispecific antibody (NBL-028) for treating Claudin 6 positive solid tumors [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 3432.