Discovery of novel 3-(1H-pyrazol-4-yl)-1H-indazole derivatives as potent type II TRK inhibitors against acquired resistance

Tropomyosin receptor kinase (Trk) is a promising target for treating NTRK fusion cancers. The solvent front and xDFG mutations induced by larotrectinib and entrectinib result in acquired resistance in advanced-stage patients. In this study, we report a highly potent and selective type II Trk Inhibitor, 40l, developed using a structure-based design strategy. Compound 40l significantly suppressed Km-12, Ba/F3-TRKA^G595R, and Ba/F3-TRKA^G667C cell proliferation. In biochemical and cellular assays, 40l showed better inhibitory activity against TrkA^G667C than that by the positive control, selitrectinib. Additionally, it induced Apoptosis of Ba/F3-TRKA^G595R and Ba/F3-TRKA^G667C cells in a dose-dependent manner. Furthermore, 40l showed good selectivity for a panel of 41 kinases. In vitro assays indicated that 40l possessed outstanding plasma stability and moderate liver microsomal stability. Based on the above results, compound 40l could be further optimized to overcome the solvent front and xDFG Trk mutations.

Acquired resistance; Anticancer; NTRK fusion; TRK inhibitors; Type II.