NCT07391774

Testing Whether Hormone Therapy With Ribociclib is as Effective as Chemotherapy Followed by Hormone Therapy With Ribociclib for the Treatment of High Anatomic Stage Breast Cancer With Low Recurrence Risk, The RxFINE-Low Trial

A Phase III Trial of Rx Therapy Guided by Genomic Risk Assessment For High Anatomic Stage ER-pos/HER2-neg Breast Cancer With RS</=25 (RxFINE-Low)

• Status: Not Yet Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 1,978 (estimated)
• Sponsor: National Cancer Institute (NCI) · NIH
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

This phase III trial compares standard of care hormone therapy plus ribociclib to chemotherapy followed by hormone therapy plus ribociclib for the treatment of patients with high anatomic stage breast cancer with low risk of the cancer returning (low risk recurrence). Ribociclib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Hormone therapy, with letrozole, anastrozole or exemestane, lowers the amount of estrogen made by the body. This may help stop the growth of tumor cells that need estrogen to grow. Chemotherapy drugs work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Hormone therapy plus ribociclib may work as well as chemotherapy followed by hormone therapy plus ribociclib for the treatment of high anatomic stage breast cancer with low recurrence risk.

Detailed description

PRIMARY OBJECTIVE: I. To determine whether optimal adjuvant endocrine therapy with CDK4/6 inhibitor is non-inferior to adjuvant chemotherapy followed by optimal endocrine therapy with CDK4/6 inhibitor as evaluated by invasive breast cancer-free survival (iBCFS). SECONDARY OBJECTIVES: I. To compare 5-year invasive disease-free survival (iDFS), distant disease-free survival (DDFS), distant recurrence-free survival (DRFS), recurrence-free interval (RFI), overall survival (OS), and breast cancer-specific survival (BCSS) in patients who receive adjuvant chemotherapy versus patients who do not. II. To compare the short-term and long-term toxicity profiles of each arm. EXPLORATORY OBJECTIVE: I. To create a biorepository of tumor tissue and peripheral blood biospecimens for future research. OUTLINE: STEP 0: Patients undergo Oncotype DX risk recurrence testing. Patients with an Oncotype DX recurrence score of 0-25 proceed to step 1. Patients with a recurrence score of 26-100 do not continue on the study. STEP 1: Patients are randomized to 1 of 2 arms. ARM A: Patients receive their physician's choice of standard of care chemotherapy. Patients then receive their physician's choice of standard of care hormone therapy with letrozole, anastrozole, or exemestane orally (PO) once daily (QD) on days 1-28 of each cycle, as well as ribociclib PO QD on days 1-21 of each cycle. Cycles repeat every 28 days for at least 60 months for hormone therapy and up to 3 years for ribociclib, in the absence of disease progression or unacceptable toxicity. Patients also undergo computed tomography (CT) scan, bone scan, or fludeoxyglucose (FDG) positron emission tomography (PET)-CT scan and may optionally undergo blood sample collection throughout the study. ARM B: Patients receive their physician's choice of standard of care hormone therapy with letrozole, anastrozole, or exemestane PO QD on days 1-28 of each cycle and ribociclib PO QD on days 1-21 of each cycle. Cycles repeat every 28 days for at least 60 months for hormone therapy and up to 3 years for ribociclib, in the absence of disease progression or unacceptable toxicity. Patients undergo CT scan, bone scan, or FDG PET-CT scan and may optionally undergo blood sample collection throughout the study. Patients are followed every 3 months for 12 months from randomization, every 6 months for years 1-5 from randomization, then every 12 months for years 5-10 from randomization.

Conditions

• Anatomic Stage II Breast Cancer AJCC v8
• Anatomic Stage IIIA Breast Cancer AJCC v8
• Anatomic Stage IIIC Breast Cancer AJCC v8
• Estrogen Receptor-Positive Breast Carcinoma
• HER2-Negative Breast Carcinoma

Interventions

Type	Name	Description
DRUG	Anastrozole	Given PO
PROCEDURE	Biospecimen Collection	Undergo blood sample collection
PROCEDURE	Bone Scan	Undergo bone scan
DRUG	Chemotherapy	Receive standard of care chemotherapy
PROCEDURE	Computed Tomography	Undergo CT scan
DRUG	Exemestane	Given PO
DRUG	Letrozole	Given PO
PROCEDURE	Oncotype DX Breast Cancer Assay	Undergo risk recurrence testing
PROCEDURE	Positron Emission Tomography	Undergo FDG PET scan
DRUG	Ribociclib Succinate	Given PO

Timeline

• Start date: 2026-07-07
• Primary completion: 2029-07-31
• Completion: 2029-07-31
• First posted: 2026-02-06
• Last updated: 2026-04-13

Regulatory

• FDA-regulated drug study