A Retrospective Analysis of Clinical Biomarkers for Olaparib Maintenance Therapy in Patients with Recurrent Ovarian Cancer.

Poly(ADP-ribose) polymerase (PARP) inhibitors theoretically promote synthetic lethality in cancer cells with homologous recombination deficiency (HRD). However, clinical evidence indicates that PARP inhibitors are also effective for treating HRD-negative ovarian cancer. The PARP inhibitor olaparib became available in Japan as a maintenance therapy for platinum-sensitive recurrent ovarian cancer regardless of homologous recombination status in April 2018. The purpose of this study was to identify potential clinical biomarkers for olaparib sensitivity in patients with recurrent ovarian cancer. Clinical information about the patients with recurrent ovarian cancer treated with olaparib maintenance therapy (OMT) was retrospectively collected. OMT duration was used as an indicator for olaparib sensitivity. The relationship between OMT duration and clinical parameters was statistically analyzed. We found a positive correlation between OMT duration and progression-free survival (PFS) or treatment free interval (TFI). In some cases, OMT duration exceeded PFS before olaparib introduction. We also found that more than half of the patients with measurable target lesions at the time of OMT introduction showed partial or complete response to OMT. These results validated the effectiveness of OMT and identified PFS and TFI as potential clinical markers for olaparib sensitivity in the patients with recurrent ovarian cancer.