A Clinical Study of Patritumab Deruxtecan to Treat Breast Cancer (MK-1022-016)

Researchers are looking for other ways to treat breast cancer (BC) that is hormone receptor-positive and human epidermal growth factor receptor 2-negative (HR+/HER2-) and either unresectable locally advanced or metastatic. * HR positive (HR+) means the cancer cells have proteins that attach to estrogen or progesterone (hormones) which help the cancer to grow and spread * HER2 negative (HER2-) means the cancer cells have a low amount of a protein called HER2 * Unresectable locally advanced means the cancer cannot be completely removed by surgery and has spread into nearby tissue or muscles * Metastatic means the cancer has spread to other parts of the body Treatment for this type of breast cancer usually includes endocrine therapy (ET) and sometimes a second treatment. The main goal of this study is to learn if people who receive patritumab deruxtecan (also known as HER3-DXd and MK-1022) live longer overall or without the cancer growing/spreading, compared to people who receive chemotherapy or a different drug called trastuzumab deruxtecan.

NCT Number	NCT07060807
Lead Sponsor	Merck Sharp & Dohme LLC Collaborators: Daiichi Sankyo
Conditions	Breast Neoplasms
Enrollment	1,000 participants
Start Date	2025-07-21
Primary Completion	2033-07-14 (estimated)
Study Completion	2033-07-14 (estimated)
Updated on ClinicalTrials.gov	2026-08-14