{"groups":[{"description":"Participants received 200 mg pembrolizumab (2 mg/kg for a maximum of 200 mg in pediatric participants) by intravenous (IV) infusion once every 3 weeks (Q3W; 21-day cycles) for up to 17 cycles (up to \\~1 year) in Part 1. Participants who completed the initial treatment of 17 cycles of pembrolizumab and experienced disease recurrence may have been eligible for re-challenge with pembrolizumab at the same dose and schedule of 200 mg Q3W (21-day cycles) for up to 35 cycles (up to \\~2 years) in Part 2.","id":"FG000","title":"Pembrolizumab"},{"description":"Participants received saline placebo by IV infusion Q3W (21-day cycles) for up to 17 cycles (up to \\~1 year) in Part 1. Participants who completed the initial treatment of 17 cycles of placebo and experienced disease recurrence may have been eligible to switch over to pembrolizumab 200 mg Q3W (21-day cycles) for up to 35 cycles (up to \\~2 years) in Part 2.","id":"FG001","title":"Placebo"}],"periods":[{"dropWithdraws":[{"reasons":[{"groupId":"FG000","numSubjects":"460"},{"groupId":"FG001","numSubjects":"459"}],"type":"Ongoing in Study"},{"reasons":[{"groupId":"FG000","numSubjects":"9"},{"groupId":"FG001","numSubjects":"10"}],"type":"Withdrawal by Subject"},{"reasons":[{"groupId":"FG000","numSubjects":"1"},{"groupId":"FG001","numSubjects":"3"}],"type":"Lost to Follow-up"},{"reasons":[{"groupId":"FG000","numSubjects":"17"},{"groupId":"FG001","numSubjects":"17"}],"type":"Death"}],"milestones":[{"achievements":[{"groupId":"FG000","numSubjects":"487"},{"groupId":"FG001","numSubjects":"489"}],"type":"STARTED"},{"achievements":[{"groupId":"FG000","numSubjects":"483"},{"groupId":"FG001","numSubjects":"486"}],"type":"Treated"},{"achievements":[{"groupId":"FG000","numSubjects":"1"},{"groupId":"FG001","numSubjects":"45"}],"type":"Re-challenged or Switched-over to Pembrolizumab"},{"achievements":[{"groupId":"FG000","numSubjects":"0"},{"groupId":"FG001","numSubjects":"0"}],"type":"COMPLETED"},{"achievements":[{"groupId":"FG000","numSubjects":"487"},{"groupId":"FG001","numSubjects":"489"}],"type":"NOT COMPLETED"}],"title":"Overall Study"}],"preAssignmentDetails":"Per protocol, response/progression or adverse events (AEs) during re-challenge/switch-over in Part 2 were not counted towards the recurrence-free survival (RFS) outcome measure or safety outcome measures respectively."}