Statement: 3/49 the primary trial Participants With HER2-expressing Metastatic and/or Unresectable Breast Cancer had a Maximum change from baseline in QTcF of over 30 ms.
Primary_evidence: Outcome Measurement:    Changes in QTcF After Treatment With DS-8201a in Participants With HER2-expressing Metastatic and/or Unresectable Breast Cancer   The number of participants with notable electrocardiogram changes meeting predefined criteria is being reported.   Time frame: Screening (within 7 days before enrollment) up to Cycle 3 Day 15 (each cycle is 21 days) Results 1:    Arm/Group Title: DS-8201a   Arm/Group Description: Participants who received 6.4 mg/kg of DS-8201a as an intravenous (IV) infusion once every 3 weeks on Day 1 of each 21-day cycle.   Overall Number of Participants Analyzed: 49   Measure Type: Count of Participants   Unit of Measure: Participants  Maximum change from baseline in QTcF: >30 ms: 3   6.1%   Maximum change from baseline in QTcF: >60 ms: 0   0.0%