Randomized, Phase 3 Study of Tesetaxel Plus a Reduced Dose of Capecitabine Versus Capecitabine Alone in Patients With HER2 Negative, HR Positive, Locally Advanced or Metastatic Breast Cancer Previously Treated With a Taxane


The primary objective is to compare the efficacy of tesetaxel plus a reduced dose of capecitabine versus the approved dose of capecitabine alone in patients with HER2 negative, HR positive LA/MBC previously treated with a taxane in the neoadjuvant or adjuvant setting.

Study Arms

  • Experimental: Arm A: Tesetaxel and Capecitabine
  • Active Comparator: Arm B: Capecitabine


  • Histologically or cytologically confirmed breast cancer
  • HER2 negative disease based on local testing: American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines should be utilized for assessing HER2 status.
  • HR (ER and/or PgR) positive disease based on local testing: ASCO/CAP guidelines should be utilized for assessing HR status.
  • Measurable disease per RECIST 1.1 or bone-only disease with lytic component.
  • Prior therapy (at least one completed dose) with a taxane-containing regimen in the neoadjuvant or adjuvant setting
  • Prior therapy with an anthracycline-containing regimen in the neoadjuvant, adjuvant, or metastatic setting, where indicated by local regulation or Investigator judgment.
  • Prior endocrine therapy with or without a CDK 4/6 inhibitor unless endocrine therapy is not indicated (ie, short relapse-free interval while on adjuvant endocrine therapy [endocrine resistance]; rapidly progressing disease/visceral crisis; or endocrine intolerance). Any targeted therapies approved for HER2 negative, HR positive LA/MBC, including everolimus, are permitted as prior therapy. There is no limit to the number of prior endocrine therapies.
  • Documented disease recurrence or disease progression of: (a) locally advanced disease that is not considered curable by surgery and/or radiation; or (b) metastatic disease.
  • Adequate hematologic, hepatic, and renal function