EFFICACY OF MAINTENANCE OLAPARIB PLUS BEVACIZUMAB BY BIOMARKER STATUS IN CLINICAL HIGHER- AND LOWER-RISK PATIENTS WITH NEWLY DIAGNOSED, ADVANCED OVARIAN CANCER IN THE PAOLA-1 TRIAL

Introduction In the Phase III PAOLA-1/ENGOT-ov25 trial (NCT02477644), adding maintenance olaparib to bevacizumab improved progression-free survival (PFS) in patients with advanced ovarian cancer in response after first-line platinumbased chemotherapy plus bevacizumab (HR 0.59; 95% CI 0.49-0.72) (Ray-Coquard et al. NEJM 2019). Outcomes in patients classified by clinical risk according to biomarker status are unknown. Methods Patients were classified as higher-risk (stage III patients with upfront surgery and residual disease or who received neoadjuvant chemotherapy, or stage IV patients) or lower-risk (stage III patients with upfront surgery and no residual disease). This exploratory analysis evaluated PFS in higher-risk and lower-risk patients, including by biomarker status: homologous recombination deficiency (HRD)-positive, HRD-negative/unknown and tumour BRCA mutation (BRCAm)-positive. Results Of 806 randomized patients, 74% were higher risk and 26% were lower risk, with median follow-up of 22.4 and 23.8 months, respectively. PFS significantly favoured olaparib plus bevacizumab versus placebo plus bevacizumab in higherrisk and lower-risk patients. In both higher- and lower-risk patients, the greatest PFS benefit was seen with olaparib plus bevacizumab versus bevacizumab alone in the HRD-positive subgroup (figures 1 and 2) and the subgroup with a tumour BRCAm (figure 2). Outcomes in the higher- and lower-risk HRD-negative/unknown subgroups are shown in figure 2. Conclusions In PAOLA-1, maintenance olaparib plus bevacizumab provided a substantial PFS benefit over bevacizumab alone in higher-risk and lower-risk patients, especially in the HRD-positive and BRCAm populations. (Table Presented).