International clinical trials such as SOLO-1 (NCT01844986) [6], PRIMA/ENGOT-OV26/GOG-3012 (NCT02655016) [7], PRIME (NCT03709316) [5], and ATHENA-Mono/GOG-3020/ENGOT-OV45 (NCT03522246) [8] have demonstrated benefits in progression-free survival when poly(ADP-ribose) polymerase (PARP) inhibitors are used for first-line maintenance treatment of patients with ovarian cancer with homologous recombination–deficient tumors. The gene discussed is PARP1; the disease is ovarian carcinoma.