EP280/#559 Real-world progression-free survival and overall survival for patients with advanced ovarian cancer utilizing PARP inhibitor second-line maintenance therapy vs active surveillance

Objectives

Since 2017, the National Comprehensive Cancer Network has recommended PARP inhibitors (PARPi) as second-line (2L) maintenance treatment for patients with BRCA± ovarian cancer (OC). We present recent estimates of real-world PFS and OS for patients on 2L PARPi maintenance therapy vs active surveillance (AS).

Methods

From an electronic health record database of US Oncology Network (~1,200 physicians from >470 sites), adult females were included if diagnosed with advanced OC, received a 2L platinum-containing regimen for advanced OC, and had ≥2 visits between 1/1/2016 and 12/1/2020. A subset of charts was further reviewed to confirm eligibility and assess PFS. Patients were followed until earliest of: 3/31/2021, last patient record, or death. Kaplan-Meier survival methods and log-rank tests were used to estimate and compare OS and PFS of the groups to 24 months.

Results

1154 patients met inclusion criteria for advanced OC and PARPi therapy or AS during the 2L maintenance period. Of these, 143 patient charts were manually reviewed (85 PARPi, 58 AS). PFS probability from initiation of 2L maintenance to 24 months was higher in the PARPi group vs AS (22% vs 10%; P=0.0004) (figure 1). OS probability was also significantly higher in the PARPi group vs AS (62% vs 47% at 24 months; P=0.0364) (figure 2).

Conclusions

This study of PARPi therapy vs AS confirms the efficacy benefits demonstrated in randomized studies of PARPis vs placebo, and provides evidence of the real-world effectiveness of PARPi maintenance therapy to improve survival in a population with advanced OC.