Fragment-based discovery of pyrazole-5-carboxamide derivatives as ALK inhibitors against non-small cell lung cancer

Anaplastic lymphoma kinase (ALK) serves as a new target for therapy in non-small cell lung cancer (NSCLC) associated with the presence of the ALK fusion gene. This study reports the development of a series of pyrazole-5-carboxamide derivatives C01-C17 based on the lead compound 7 and hit compound A06 obtained through virtual screening, which was identified through fragment-based drug design. After structural optimization, the selected compound C04 exhibits significant anti-proliferative effects against the ALK-overexpressing cell line H2228 (IC₅₀ = 0.10 μM), as well as promising ALK inhibition (9.58 nM). Molecular docking studies suggest that C04 functions as a type I₁/₂ allosteric inhibitor by forming critical interactions within the ATP-binding region and the hydrophobic pocket of ALK. Furthermore, C04 induces apoptosis in H2228 cells in a dose-dependent manner, inhibits colony formation, and suppresses tumor cell migration. These findings provide new insights into the search for novel ALK inhibitors.