Background: In SOLO1 (NCT01844986), maintenance olaparib provided a substantial progression-free survival benefit vs placebo in newly diagnosed pts with advanced OC, a BRCAm and clinical complete or partial response to platinum therapy (HR 0.30; 95% CI 0.23–0.41) and was well tolerated (Moore et al.NEJM 2018). We analysed the most common AEs and hematologic AEs in SOLO1. Methods: Pts received olaparib tablets 300 mg twice daily or placebo until progression unless they had no evidence of disease at 2 years, in which case treatment stopped. AEs were graded using CTCAE v4.0. Results: Of 391 pts randomized, 390 (olaparib, 260; placebo, 130) were treated and included in the safety analysis. Median treatment duration was approximately 25 months for olaparib vs 14 for placebo. Median time to first onset of the most common AEs (nausea, vomiting, fatigue/asthenia, anemia) and neutropenia and thrombocytopenia was < 3 months; the first event lasted a median of < 2 months, apart from fatigue/asthenia, which lasted a median of < 4 months (Table). AEs were usually managed with supportive therapy and/or dose modification; few pts discontinued. Conclusions: AEs in newly diagnosed pts with advanced OC treated with olaparib usually occurred early and were manageable, with few discontinuations. Clinical trial information: NCT01844986

*Grouped term; ^†AEs with no end date censored at end of safety follow-up or data cut-off, as applicable. O, olaparib; P, placebo