Clinical Use of PARP Inhibitors in BRCA Mutant and Non-BRCA Mutant Breast Cancer.

The use of poly(ADP-ribose) polymerase (PARP) inhibitors for the treatment of patients with germline BRCA mutations (gBRCAm) and breast cancer, both in the early and advanced settings, is a success of genomically-directed treatment. These agents have been shown to be associated with longer progression-free survival when compared to standard chemotherapy, with an acceptable toxicity profile. A recent randomized trial demonstrated improved survival with the use of olaparib for 2 years compared to placebo in patients with early-stage high risk gBRCAm associated breast cancer. Ongoing research efforts are focused on identifying patients beyond those with BRCA1/2 or PALB2 mutations who may benefit from PARP inhibitors, exploring the overlapping mechanisms of resistance between platinum and PARP inhibitors and developing agents with less toxicity that will allow combinational strategies.