{"groups":[{"description":"Participants received letrozole 2.5 milligram (mg) orally QD (once daily) combined with palbociclib 125 mg QD for 21 days of every-28-day cycle, followed by 7 days off treatment.","id":"FG000","title":"Palbociclib Plus Letrozole"},{"description":"Participants received letrozole 2.5 mg orally QD combined with placebo QD for 21 days of every-28-day cycle, followed by 7 days off treatment.","id":"FG001","title":"Placebo Plus Letrozole"}],"periods":[{"dropWithdraws":[{"reasons":[{"groupId":"FG000","numSubjects":"286"},{"groupId":"FG001","numSubjects":"172"}],"type":"Objective Progression or Relapse"},{"reasons":[{"groupId":"FG000","numSubjects":"32"},{"groupId":"FG001","numSubjects":"9"}],"type":"Adverse Event"},{"reasons":[{"groupId":"FG000","numSubjects":"28"},{"groupId":"FG001","numSubjects":"12"}],"type":"Global Deterioration of Health Status"},{"reasons":[{"groupId":"FG000","numSubjects":"27"},{"groupId":"FG001","numSubjects":"15"}],"type":"Participant Refused Continued Treatment"},{"reasons":[{"groupId":"FG000","numSubjects":"52"},{"groupId":"FG001","numSubjects":"8"}],"type":"Unspecified reasons"},{"reasons":[{"groupId":"FG000","numSubjects":"10"},{"groupId":"FG001","numSubjects":"3"}],"type":"Death"},{"reasons":[{"groupId":"FG000","numSubjects":"5"},{"groupId":"FG001","numSubjects":"3"}],"type":"Protocol Violation"},{"reasons":[{"groupId":"FG000","numSubjects":"3"},{"groupId":"FG001","numSubjects":"0"}],"type":"Lost to Follow-up"},{"reasons":[{"groupId":"FG000","numSubjects":"1"},{"groupId":"FG001","numSubjects":"0"}],"type":"Site Terminated by Sponsor"}],"milestones":[{"achievements":[{"groupId":"FG000","numSubjects":"444"},{"groupId":"FG001","numSubjects":"222"}],"type":"STARTED"},{"achievements":[{"groupId":"FG000","numSubjects":"0"},{"groupId":"FG001","numSubjects":"0"}],"type":"COMPLETED"},{"achievements":[{"groupId":"FG000","numSubjects":"444"},{"groupId":"FG001","numSubjects":"222"}],"type":"NOT COMPLETED"}],"title":"Overall Study"}],"preAssignmentDetails":"The study consisted of a screening visit within 28 days before randomization, an active treatment phase, divided in cycles of 28 days each, and a post-treatment follow-up period during which survival and new anti-cancer therapy information was collected every 6 months (±7 days) from the last dose of study treatment.","recruitmentDetails":"A total of 666 participants were randomized at 239 centers in 19 countries."}