Patient-centred outcomes and effect of disease progression on health status in patients with newly diagnosed advanced ovarian cancer and a BRCA mutation receiving maintenance olaparib or placebo (SOLO1): a randomised, phase 3 trial

Background In the phase 3 SOLO1 trial, maintenance olaparib provided a significant progression-free survival benefit versus placebo in patients with newly diagnosed, advanced ovarian cancer and a BRCA mutation in response after platinum-based chemotherapy. We analysed health-related quality of life (HRQOL) and patient-centred outcomes in SOLO1, and the effect of radiological disease progression on health status. Methods SOLO1 is a randomised, double-blind, international trial done in 118 centres and 15 countries. Eligible patients were aged 18 years or older; had an Eastern Cooperative Oncology Group performance status score of 0-1; had newly diagnosed, advanced, high-grade serous or endometrioid ovarian cancer, primary peritoneal cancer, or fallopian tube cancer with a BRCA mutation; and were in clinical complete or partial response to platinum-based chemotherapy. Patients were randomly assigned (2:1) to either 300 mg olaparib tablets or placebo twice per day using an interactive voice and web response system and were treated for up to 2 years. Treatment assignment was masked for patients and for clinicians giving the interventions, and those collecting and analysing the data. Randomisation was stratified by response to platinum-based chemotherapy (clinical complete or partial response). HRQOL was a secondary endpoint and the prespecified primary HRQOL endpoint was the change from baseline in the Functional Assessment of Cancer Therapy-Ovarian Cancer Trial Outcome Index (TOI) score for the first 24 months. TOI scores range from 0 to 100 (higher scores indicated better HRQOL), with a clinically meaningful difference defined as a difference of at least 10 points. Prespecified exploratory endpoints were quality-adjusted progression-free survival and time without significant symptoms of toxicity (TWiST). HRQOL endpoints were analysed in all randomly assigned patients. The trial is ongoing but closed to new participants. This trial is registered with ClinicalTrials.gov, NCT01844986. Findings Between Sept 3, 2013, and March 6, 2015, 1084 patients were enrolled. 693 patients were ineligible, leaving 391 eligible patients who were randomly assigned to olaparib (n=260) or placebo (n=131; one placebo patient withdrew before receiving any study treatment), with a median duration of follow-up of 40.7 months (IQR 34.9-42.9) for olaparib and 41.2 months (32.2-41.6) for placebo. There was no clinically meaningful change in TOI score at 24 months within or between the olaparib and placebo groups (adjusted mean change in score from baseline over 24 months was 0.30 points [95% CI -0.72 to 1.32] in the olaparib group vs 3.30 points [1.84 to 4.76] in the placebo group; between-group difference of -3.00, 95% CI -4.78 to -1.22; p=0.0010). Mean quality-adjusted progression-free survival (olaparib 29.75 months [95% CI 28.20-31.63] vs placebo 17.58 [15.05-20.18]; difference 12.17 months [95% CI 9.07-15.11], p<0.0001) and the mean duration of TWiST (olaparib 33.15 months [95% CI 30.82-35.49] vs placebo 20.24 months [17.36-23.11]; difference 12.92 months [95% CI 9.30-16.54]; p<0.0001) were significantly longer with olaparib than with placebo. Interpretation The substantial progression-free survival benefit provided by maintenance olaparib in the newly diagnosed setting was achieved with no detrimental effect on patients' HRQOL and was supported by clinically meaningful quality-adjusted progression-free survival and TWiST benefits with maintenance olaparib versus placebo. Copyright (C) 2021 Elsevier Ltd. All rights reserved.