Antiproliferative agent-53-d3 (Compound C1) is an inhibitor for theta-mediated end joining (TMEJ) in HEK293 cell with an IC 50 of 0.14 µM. Antiproliferative agent-53-d3 is the inhibitor for CYP2C19 and CYP2C9 with IC 50 of 0.77 and 3.1 µM. Antiproliferative agent-53-d3 inhibits the proliferation of DNA repair-compromised cells, with IC 50 of 8.1 µM for BRCA2 -/- DLD-1. Antiproliferative agent-53-d3 exhibits good pharmacokinetic characteristics in CD-1 mice.