Ascentage Pharma, a global biopharmaceutical company engaged in developing novel therapies for cancers, chronic hepatitis B (CHB), and age-related diseases, announced that its novel inhibitor of the embryonic ectoderm development (EED) protein, APG-5918, has been approved by the Center for Drug Evaluation (CDE) of China National Medical Products Administration (NMPA) to enter a Phase I study in patients with advanced solid tumors or hematologic malignancies. Following the recent clearance for the study in the US, this approval in China marks another milestone for the company’s strategy of simultaneous clinical development in the two countries. APG-5918 is the first domestically developed novel EED inhibitor entering clinical development in China.
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This multicenter, open-label Phase I dose-escalation and dose-expansion study is designed to assess the safety, pharmacokinetics, and efficacy of orally administered APG-5918 in patients with advanced solid tumors or hematologic malignancies. Prof. Ruihua Xu, President and Director of Sun Yat-Sen University Cancer Center, and President of the Chinese Society of Clinical Oncology, will be the principal investigator of this study.
EZH2, which is highly expressed in multiple tumors in humans, was found to promote the development and progression of tumors, and targeted inhibition of EZH2’s methyltransferase activity has already proved to be an effective mechanistic approach for cancer treatment. However, the secondary mutation of EZH2 may lead to acquired drug resistances, while the homologous EZH1 also has methyltransferase (MTase) activity that could limit the effects of EZH2 inhibitors. Studies have shown that the PRC2 complex’s component proteins and EZH2’s histone activities are highly dependent on the scaffold and modulating effects of EED. Compounds with inhibitory effects on EED, a subunit of PRC2, can disrupt the protein-to-protein interaction between EED and EZH2, culminating in damaged PRC2 functions, H3K27me3-induced silencing of PRC2 expressions, and blockade of the triple-methylation of H3K27.1 Therefore, allosteric targeting of EED has in recent years gained a great deal of traction as a promising approach for inhibiting the replacement of inactivated PRC2.