TRK-IN-29 (Compound B31) is a second-generation TRK inhibitor with IC50 values of 9 nM for TRKAG595R, 0.6 nM for TRKAF589L, 18 nM for TRKAG667C, 5 nM for TRKA, and 6 nM for TRKC. It effectively inhibits the phosphorylation of TRKA and demonstrates significant antiproliferative activity against NTRK fusion-positive cells. TRK-IN-29 also exhibits excellent plasma stability and moderate pharmacokinetic properties.