There are some minor differences between the indications of these drugs in Europe and USA, based on different clinical trials.7, 8, 10 All three PARP inhibitors approved for ovarian cancer treatment have substantial PFS advantages over placebo in the maintenance setting.11, 12 Clinical trials of these three PARP inhibitors are ongoing, and these drugs are expected to have substantial PFS advantages over placebo in the treatment setting as well. This evidence concerns the gene PARP1 and ovarian cancer.