In-depth theoretical modeling to explore the mechanism of TPX-0131 overcoming lorlatinib resistance to ALKL1196M/G1202R mutation

Abstract

A number of anaplastic lymphoma kinase (ALK) inhibitors have been clinically approved, with lorlatinib, particularly as a third-generation drug, demonstrating efficacy against various drug-resistant ALK single mutations. However, continued clinical use of lorlatinib has led to the emergence of ALK double mutations conferring resistance to lorlatinib, notably ALK^{L1196M/G1202R}. TPX-0131 is a potential fourth-generation ALK inhibitor currently under development. TPX-0131 demonstrates a broader spectrum of activity against ALK-resistant mutations, efficiently inhibiting 26 single-point mutations and various double/triple mutations, including solvent front mutations and gatekeeper mutations. In this study, for the first time, a comprehensive elucidation of the molecular mechanisms by which TPX-0131 overcomes lorlatinib resistance to ALK^{L1196M/G1202R} through modeling, MD simulations, free energy calculations, and US simulations. The results indicate that the interactions between lorlatinib and key residues at the hinge region are disturbed by L1196M/G1202R double mutation, leading to the disruption of important hydrogen bonding between Glu1197 and lorlatinib. For TPX-0131, the L1196M/G1202R mutation enhances electrostatic and van der Waals interactions, causing significant conformational changes primarily in the hinge region, G-loop, and β-strands. The tight binding of TPX-0131 to residues Arg1202, Met1199 and Arg1120 contribute significantly to overcoming lorlatinib resistance in ALK^{L1196M/G1202R} mutant. These research results are expected to offer insights into the mechanism of TPX-0131 in treating ALK^{G1202R/L1196M}-induced NSCLC resistance and optimizing of ALK inhibitors.

Keywords: Anaplastic lymphoma kinase; Drug resistance mechanism; L1196M/G1202R; TPX-0131; Umbrella sampling.