An Open-label, Randomized, Phase 3 Study to Evaluate Patritumab Deruxtecan Monotherapy versus Treatment of Physicians Choice in Hormone Receptorpositive, HER2-negative Unresectable Locally Advanced or Metastatic Breast Cancer [HERTHENA-Breast04] (NCT07060807)

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.

Trial phase

Phase 3

Trial participation type

This trial has been designed for the Clinical Research of a Drug.

Principal investigator

Dr Lucy Gately

Key inclusion data

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.