Study on DS-8201a for Previously Treated HER2 Breast Cancer That Cannot Be Surgically Removed or Has Spread [DESTINY-Breast02]

Inclusion Criteria

• Be an adult according to the laws of their country.
• Have breast cancer that:
  • Cannot be removed by surgery or has spread to other parts of the body.
  • Is confirmed to be HER2-positive based on specific medical guidelines.
  • Has been previously treated with a drug called T-DM1.
• Show signs of cancer progression on scans, either during or after the most recent treatment, or within 6 months after finishing adjuvant therapy.
• Have HER2-positive status confirmed by a central lab using the most recent tumor sample. If no archived tissue is available, agree to provide a new biopsy.
• Agree to use effective birth control or avoid intercourse during the study and for a specified time after the last dose of study drugs.
• Have adequate blood, kidney, and liver function.

Exclusion Criteria

• Have participated in a previous study involving an antibody drug conjugate by Daiichi Sankyo, unless it was in an adjuvant/neo-adjuvant setting and the disease did not progress within 12 months after treatment.
• Have had prior treatment with a drug called capecitabine.
• Have uncontrolled or serious heart disease.
• Have a history of lung disease that required steroids, currently have lung disease, or have suspected lung disease that cannot be ruled out by imaging.
• Have active cancer that has spread to the brain or central nervous system.