Clinical Trial

Evaluating the Addition of Adjuvant Chemotherapy to Ovarian Function Suppression Plus Endocrine Therapy in Premenopausal Patients With pN0-1, ER-Positive/HER2-Negative Breast Cancer and an Oncotype Recurrence Score Less Than or Equal to 25

Study acronym: OFSET
Recruiting Phase 3
View on ClinicalTrials.gov →
Summary
This Phase III Trial will determine whether adjuvant chemotherapy (ACT) added to ovarian function suppression (OFS) plus endocrine therapy (ET) is superior to OFS plus ET in improving invasive breast cancer-free survival (IBCFS) among premenopausal, early- stage breast cancer (EBC) patients with estrogen receptor (ER)-positive, HER2-negative tumors and 21-gene recurrence score (RS) between 16-25 (for pN0 patients) and 0-25 (for pN1 patients).
Protocol Amendment History 5 changes
notable Trial sites expanded: 1249 -> 1259 locations 2026-08-05
notable Trial sites expanded: 1243 -> 1249 locations 2026-07-03
notable Trial sites expanded: 1238 -> 1243 locations 2026-06-04
notable Trial sites expanded: 1224 -> 1238 locations 2026-05-05
notable Trial sites expanded: 1209 -> 1224 locations 2026-04-03
Trial Details
NCT Number NCT05879926
Lead Sponsor NRG Oncology
Collaborators: National Cancer Institute (NCI)
Conditions Breast Cancer
Enrollment 3,960 participants
Start Date 2023-10-18
Primary Completion 2032-01 (estimated)
Study Completion 2034-07 (estimated)
Updated on ClinicalTrials.gov 2026-08-04