A first-in-human phase I study of TAS0728, an oral covalent binding inhibitor of HER2, in patients with advanced solid tumors with HER2 or HER3 aberrations

Unraveling the future: Innovative design strategies and emerging challenges in HER2-targeted tyrosine kinase inhibitors for cancer therapy

Human epidermal growth factor receptor 2 (HER2) is a transmembrane receptor-like protein with tyrosine kinase activity that plays a vital role in processes such as cell proliferation, differentiation, and angiogenesis. The degree of malignancy of different cancers, notably breast cancer, is strongly associated with HER2 amplification, overexpression, and mutation. Currently, widely used clinical HER2 tyrosine kinase inhibitors (TKIs), such as lapatinib and neratinib, have several drawbacks, including susceptibility to drug resistance caused by HER2 mutations and adverse effects from insufficient HER2 selectivity. To address these issues, it is essential to create innovative HER2 TKIs with enhanced safety, effectiveness against mutations, and high selectivity. Typically, SPH5030 has advanced to phase I clinical trials for its strong suppression of four HER2 mutations. This review discusses the latest research progress in HER2 TKIs, with a focus on the structural optimization process and structure-activity relationship analysis. In particular, this study highlights promising design strategies to address these challenges, providing insightful information and inspiration for future development in this field.

Design and Development of a Chemical Probe for Pseudokinase Ca2+/calmodulin-Dependent Ser/Thr Kinase

CASK (Ca²⁺/calmodulin-dependent Ser/Thr kinase) is a member of the MAGUK (membrane-associated guanylate kinase) family that functions as neurexin kinases with roles implicated in neuronal synapses and trafficking. The lack of a canonical DFG motif, which is altered to GFG in CASK, led to the classification as a pseudokinase. However, functional studies revealed that CASK can still phosphorylate substrates in the absence of divalent metals. CASK dysfunction has been linked to many diseases, including colorectal cancer, Parkinson's disease, and X-linked mental retardation, suggesting CASK as a potential drug target. Here, we exploited structure-based design for the development of highly potent and selective CASK inhibitors based on 2,4-diaminopyrimidine-5-carboxamides targeting an unusual pocket created by the GFG motif. The presented inhibitor design offers a more general strategy for the development of pseudokinase ligands that harbor unusual sequence motifs. It also provides a first chemical probe for studying the biological roles of CASK.