PARP-1/2-IN-2-IN-1 (Compound 12e) is a PARP1/2/CDK12 inhibitor (IC50: 34, 30 and 285 nM respectively). PARP-1/2-IN-2 inhibits DNA damage repair, promotes cell cycle arrest and apoptosis. PARP-1/2-IN-2 inhibits the growth of TNBC cells and TNBC xenograft tumor[1].