{"groups":[{"description":"Participants received T-DXd 5.4 milligram per kilogram (mg/kg) via intravenous (IV) infusion every 3 weeks until disease progression (PD), unacceptable toxicity, withdrawal of consent, or another criterion for discontinuation was met.","id":"FG000","title":"T-DXd"},{"description":"Participants received Investigator's choice single-agent chemotherapy (capecitabine 1000 or 1250 mg per meter square \\[m\\^2\\] orally twice daily for 2 weeks followed by a 1-week rest period in 3-week cycles, paclitaxel 80 mg/m\\^2 via IV infusion every week \\[qw\\] in 3-week cycles or nab-paclitaxel 100 mg/m\\^2 via IV infusion qw for 3 weeks followed by 1-week rest period in 4-week cycles) until PD, unacceptable toxicity, withdrawal of consent, or another criterion for discontinuation was met.","id":"FG001","title":"Chemotherapy"}],"periods":[{"dropWithdraws":[{"reasons":[{"groupId":"FG000","numSubjects":"160"},{"groupId":"FG001","numSubjects":"166"}],"type":"Death"},{"reasons":[{"groupId":"FG000","numSubjects":"10"},{"groupId":"FG001","numSubjects":"40"}],"type":"Withdrawal by Subject"},{"reasons":[{"groupId":"FG000","numSubjects":"1"},{"groupId":"FG001","numSubjects":"1"}],"type":"Other"},{"reasons":[{"groupId":"FG000","numSubjects":"265"},{"groupId":"FG001","numSubjects":"223"}],"type":"Ongoing at the time of PCD"}],"milestones":[{"achievements":[{"groupId":"FG000","numSubjects":"436"},{"groupId":"FG001","numSubjects":"430"}],"comment":"Randomized","type":"STARTED"},{"achievements":[{"groupId":"FG000","numSubjects":"434"},{"groupId":"FG001","numSubjects":"417"}],"type":"Randomized and Received Treatment"},{"achievements":[{"groupId":"FG000","numSubjects":"0"},{"groupId":"FG001","numSubjects":"0"}],"type":"COMPLETED"},{"achievements":[{"groupId":"FG000","numSubjects":"436"},{"groupId":"FG001","numSubjects":"430"}],"type":"NOT COMPLETED"}],"title":"Overall Study"}],"preAssignmentDetails":"866 participants were randomized in a 1:1 ratio to receive trastuzumab deruxtecan (T-DXd) or standard of care: Investigator's choice single agent chemotherapy (capecitabine, paclitaxel or nab-paclitaxel). As pre-specified in the protocol and statistical analysis plan (SAP), results are presented by treatment group.","recruitmentDetails":"This Phase III, multi-center, open-label study was conducted in participants with human epidermal growth factor receptor 2 (HER2)-low, hormone receptor-positive (HR+) breast cancer at 273 sites in 28 countries. Results are presented based on primary completion date (PCD) of up to 18 March 2024."}