Phase III Study Comparing Giredestrant and Fulvestrant with a CDK46 Inhibitor in Adults with Estrogen Receptor-Positive, HER2-Negative Advanced Breast Cancer Resistant to Adjuvant Endocrine Therapy

What this Trial Is About

Researchers are conducting a Phase III, randomized, open-label multicenter study to evaluate the effectiveness and safety of giredestrant compared with fulvestrant. Both drugs are combined with the investigators choice of a CDK46 inhibitor palbociclib, ribociclib, or abemaciclib in participants with estrogen receptor-positive ER, HER2-negative advanced breast cancer who have become resistant to prior adjuvant endocrine therapy. Participants will be randomly assigned to one of two groups one group will receive giredestrant 30 mg orally daily on Days 1-28 of each 28-day cycle, while the other will receive fulvestrant 500 mg intramuscularly on Days 1 and 15 of Cycle 1 and Day 1 of subsequent 28-day cycles. Both groups will also receive a CDK46 inhibitor chosen by the investigator, with dosing schedules depending on the specific inhibitor selected. Preperimenopausal women and men will receive a luteinizing hormone-releasing hormone LHRH agonist during treatment. Participants will be assessed for progression-free survival over up to 5 years, with additional measures including overall survival, response rates, duration of response, clinical benefit, and quality of life. Safety will be monitored through adverse event reporting, vital signs, and laboratory tests during treatment and up to 28 days after the last dose. The study is led by Hoffmann-La Roche and aims to provide detailed information on the treatments effects in this patient population.

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)