PARP Inhibitors in the Management of Ovarian Cancer: ASCO Living Guideline, Version 2026.1.0

PURPOSE This living guideline provides recommendations on the use of poly(ADP-ribose) polymerase inhibitors (PARPis) in the management of epithelial ovarian cancer (EOC). METHODS An Expert Panel developed recommendations based on a systematic review of randomized controlled trials, and cohort studies evaluating homologous recombination deficiency (HRD) testing and PARPi efficacy and safety. RESULTS The updated evidence base comprises 79 publications, including 18 studies evaluating 13 homologous recombination deficiency (HRD) assays and 31 pivotal trials assessing PARPi efficacy and safety. Frontline trials demonstrated progression-free survival benefits. However, later-line treatment and recurrent maintenance trials reported potential overall survival disadvantages. RECOMMENDATIONS All patients with newly diagnosed advanced EOC should undergo genetic testing, and HRD tumor testing if BRCA -negative, using FDA-approved or prospectively validated companion diagnostic assays. In advanced EOC, PARPi maintenance should be prioritized for the first clinical remission. Frontline PARPi monotherapy maintenance should be offered after platinum-based chemotherapy response to patients with germline or somatic BRCA 1/2 mutations or HRD-positive disease. Olaparib plus bevacizumab maintenance may be offered to patients responding to first-line platinum-based chemotherapy plus bevacizumab who have BRCA 1/2 mutations or HRD-positive disease. PARPi maintenance therapy is not recommended for patients with non- BRCA mut HRD-negative tumors or early-stage EOC. In the recurrent setting, PARPi maintenance should be restricted primarily to PARPi-naïve patients with BRCA 1/2 mutations responding to second-line or greater platinum-based chemotherapy. Monotherapy PARPi should not be offered for the treatment of recurrent EOC outside clinical trials. Furthermore, PARPi are not recommended for use in combination with chemotherapy, other targeted agents, or immune-oncology agents outside a clinical trial. Clinicians should monitor for serious adverse events, including myelodysplastic syndrome, acute myeloid leukemia, and pulmonary complications.