An Open-label, Randomized, Phase 3 Study to Evaluate Patritumab Deruxtecan Monotherapy Versus Treatment of Physician's Choice in Hormone Receptor-positive, HER2-negative Unresectable Locally Advanced or Metastatic Breast Cancer (HERTHENA-Breast04)
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.
∙ The main inclusion criteria include but are not limited to the following:
• Has a diagnosis of hormone receptor positive (HR+)/human epidermal growth factor receptor 2 (HER2)- invasive breast carcinoma that is either locally advanced disease not amenable to resection with curative intent (herein called unresectable) or metastatic disease not treatable with curative intent
• Has centrally-confirmed HR+ and HER2- results and human epidermal growth factor receptor 3 (HER3) evaluable results from a biopsy obtained from a distant metastatic site or a locally advanced lesion on or after the most recent line of therapy (with certain exceptions)
• Must have had progression or recurrence on prior cyclin-dependent kinase (CDK)4/6 inhibitor + endocrine therapy (ET) with one of the following:
‣ Radiographic disease progression, as assessed by the investigator, on CDK4/6 inhibitor + ET as 1L for treatment of unresectable locally advanced or metastatic HR+/HER2- breast cancer. CDK4/6 inhibitor + ET must be the only line of therapy received in the advanced setting, or
⁃ Disease recurrence, either radiographic and/or confirmed histologically via biopsy as assessed by the investigator, while on adjuvant ET in combination with a CDK4/6 inhibitor OR within 24 months from the date of last dose of adjuvant CDK4/6 inhibitor
• Has measurable disease per RECIST 1.1 as assessed by the local site investigator/radiology
• Human immunodeficiency virus (HIV)-infected participants must have well controlled HIV on antiretroviral therapy
• Has an Eastern Cooperative Oncology Group performance status of 0 or 1 assessed within 7 days before randomization