{"groups":[{"description":"Participants with locally advanced human epidermal growth factor receptor 2-positive (HER2+)/metastatic breast cancer (mBC) were allocated to receive tucatinib 300 milligrams (mg) orally (PO) twice a day (BID) with trastuzumab 6 mg per kilograms (mg/kg) intravenously (IV) or at a fixed dose of 600 mg subcutaneously (SC), and pertuzumab 420 mg IV once every 21 days. Participants may also have received a fixed dose combination of 600 mg pertuzumab, 600 mg trastuzumab, and 20,000 units hyaluronidase SC, once every 21 days. Participants received study treatment until unacceptable toxicity, disease progression, withdrawal of consent, or study closure.","id":"FG000","title":"Tucatinib + Trastuzumab + Pertuzumab"},{"description":"Participants with locally advanced HER2+/mBC were allocated to receive placebo PO BID, and trastuzumab 6 mg/kg IV or SC at a fixed dose of 600 mg, every 21 days, and pertuzumab 420 mg IV, every 21 days. Participants may also have received a fixed dose combination of 600 mg pertuzumab, 600 mg trastuzumab, and 20,000 units hyaluronidase SC, once every 21 days. Participants received study treatment until unacceptable toxicity, disease progression, withdrawal of consent, or study closure","id":"FG001","title":"Placebo + Trastuzumab + Pertuzumab"}],"periods":[{"dropWithdraws":[{"reasons":[{"groupId":"FG000","numSubjects":"18"},{"groupId":"FG001","numSubjects":"33"}],"type":"Death"},{"reasons":[{"groupId":"FG000","numSubjects":"9"},{"groupId":"FG001","numSubjects":"4"}],"type":"Withdrawal by Subject"},{"reasons":[{"groupId":"FG000","numSubjects":"299"},{"groupId":"FG001","numSubjects":"291"}],"type":"Ongoing"}],"milestones":[{"achievements":[{"groupId":"FG000","numSubjects":"326"},{"groupId":"FG001","numSubjects":"328"}],"comment":"As Randomized.","type":"STARTED"},{"achievements":[{"groupId":"FG000","numSubjects":"326"},{"groupId":"FG001","numSubjects":"328"}],"type":"Intent-to-Treat (ITT) Analysis Set"},{"achievements":[{"groupId":"FG000","numSubjects":"326"},{"groupId":"FG001","numSubjects":"324"}],"type":"Safety Analysis Set (SAS)"},{"achievements":[{"groupId":"FG000","numSubjects":"0"},{"groupId":"FG001","numSubjects":"0"}],"type":"COMPLETED"},{"achievements":[{"groupId":"FG000","numSubjects":"326"},{"groupId":"FG001","numSubjects":"328"}],"type":"NOT COMPLETED"}],"title":"Overall Study"}],"preAssignmentDetails":"Results reported are based on the primary completion date (PCD) of the study; data for only those secondary outcome measures are reported for which analyses were complete at PCD. Remaining outcome measures would be reported upon completion of their analyses at study completion."}