O026/#560 Efficacy Analysis by Disease Risk Subgroup for the Phase 3 Athena-Mono Study (Gog-3020/Engot-ov45) Evaluating Rucaparib Maintenance Treatment in Patients with Newly Diagnosed Ovarian Cancer

ObjectivesIn ATHENA-MONO (NCT03522246), progression-free survival (PFS) improved with first-line rucaparib maintenance treatment vs placebo in patients with advanced ovarian cancer (OC), regardless of molecular characteristics (median PFS: 20.2 vs 9.2 months, log-rank P<0.0001; hazard ratio: 0.52; 95% CI: 0.40–0.68). Patients with or without high-risk clinical characteristics for disease progression were enrolled; in this subgroup analysis, we investigated whether all patients benefited from rucaparib first-line maintenance treatment, including those with more favorable baseline prognostic factors.MethodsPatients with high-grade, FIGO stage III–IV OC who completed cytoreductive surgery and 4–8 cycles of first-line platinum-doublet chemotherapy with a response were randomized 4:1 to oral rucaparib 600 mg BID or placebo. Investigator-assessed PFS was evaluated in subgroups based on FIGO stage, timing of surgery, and residual disease status post-chemotherapy.ResultsAs of Mar 23, 2022 (data cutoff), 427 and 111 patients were randomized to rucaparib monotherapy or placebo. Most patients had FIGO stage III disease (75%); approximately half underwent primary surgery (49%), and most had no residual disease (75%). In the intent-to-treat population, PFS improved with rucaparib vs placebo across all subgroups based on FIGO stage, timing of surgery, and residual disease (table 1).ConclusionsIn the intent-to-treat population, first-line rucaparib maintenance treatment improved PFS vs placebo across subgroups regardless of timing of surgery or prognostic disease characteristics such as FIGO stage or residual disease. These results confirm rucaparib as a new effective maintenance treatment for OC patients with or without high-risk factors for progression at baseline, irrespective of molecular characteristics.