A Study to Evaluate Efficacy and Safety of Giredestrant Compared With Fulvestrant (Plus a CDK4/6 Inhibitor), in Participants With ER-Positive, HER2-Negative Advanced Breast Cancer Resistant to Adjuvant Endocrine Therapy (pionERA Breast Cancer)

This is a Phase III, randomized, open-label multicenter study that will evaluate the efficacy and safety of giredestrant compared with fulvestrant, both in combination with the investigator's choice of a CDK4/6 inhibitor (palbociclib, ribociclib or abemaciclib), in participants with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer who have developed resistance to adjuvant endocrine therapy.

NCT Number	NCT06065748
Lead Sponsor	Hoffmann-La Roche
Conditions	Estrogen Receptor-Positive, HER2-Negative Advanced Breast Cancer
Enrollment	1,050 participants
Start Date	2023-12-11
Primary Completion	2027-02-19 (estimated)
Study Completion	2029-02-12 (estimated)
Updated on ClinicalTrials.gov	2026-07-06