Background: Ovarian cancer (OC) is the fifth leading cause of cancer death among women. Poly(ADP-ribose) polymerase inhibitors (PARPis) are recommended following response to second-line (2L) chemotherapy as 2L maintenance treatment by the National Comprehensive Cancer Network for OC patients (pts), based on results from clinical trials demonstrating their ability to extend progression-free survival (PFS), the time between chemotherapy and relapse, in this patient population. We present recent estimates of real-world PFS and overall survival (OS) for pts on 2L PARPi maintenance therapy vs active surveillance. Methods: From the iKnowMed electronic health record database and a review of patient charts within the US Oncology Network, which includes 1200 physicians operating in over 470 sites of care in the US, adult females were included if they were diagnosed with advanced OC, had received a 2L platinum-containing regimen for advanced OC, and had ≥2 visits within the database between 1 Jan 2016 and 1 Dec 2020. Among these, a subset of charts were reviewed to confirm eligibility and to assess PFS. Patients were followed longitudinally until 31 March 2021, the last pt record, or date of death, whichever occurred earliest. Kaplan-Meier survival methods and log-rank tests were used to estimate and compare the OS as well as PFS of the groups to 24 months. Results: A total of 1154 pts met study inclusion criteria for advanced OC and either a PARPi or active surveillance for the 2L maintenance period. Of these, 142 patient charts were further manually reviewed to assess real-world PFS: 84 received a PARPi, and 58 received active surveillance. Median age at the start of 2L maintenance was 65.7 years and was not significantly different between groups. There was a significant difference in the distribution of the ECOG PS category between groups (ECOG PS 0: 22.6% vs 1.7%, ECOG PS 1: 39.3% vs 50.0%, for PARPi vs active surveillance, respectively; P< 0.0001). Median follow-up time from discontinuation of 2L platinum chemotherapy until the end of observation was significantly longer in the active surveillance group (41.5 vs 23.5 months; P< 0.0001). PFS probability from the beginning of 2L maintenance was higher in the PARPi group vs active surveillance (24% vs 10% at 24 months; P= 0.0003). OS probability was also significantly higher in the PARPi group vs active surveillance (78% vs 55% at 24 months; P= 0.0272). Conclusions: This study of PARPi therapy vs active surveillance confirms the efficacy benefits that have been demonstrated in randomized clinical trials of PARPis vs placebo, and it provides further evidence of the real-world effectiveness of PARPi maintenance therapy to improve survival in a population with advanced OC.