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)
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ClinicalTrials.gov Identifier: NCT06065748 |
Recruitment Status :
Recruiting
First Posted : October 4, 2023
Last Update Posted : November 7, 2023
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Condition or disease | Intervention/treatment | Phase |
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Estrogen Receptor-Positive, HER2-Negative Advanced Breast Cancer | Drug: Giredestrant Drug: Fulvestrant Drug: Abemaciclib Drug: Palbociclib Drug: Ribociclib Drug: LHRH Agonist Diagnostic Test: FoundationOne Liquid CDx Assay (F1LCDx) | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 1050 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | A Phase III Randomized, Open-Label Study Evaluating Efficacy and Safety of Giredestrant Compared With Fulvestrant, Both Combined With a CDK4/6 Inhibitor, in Patients With Estrogen Receptor-Positive, HER2-Negative Advanced Breast Cancer With Resistance to Prior Adjuvant Endocrine Therapy |
Estimated Study Start Date : | November 24, 2023 |
Estimated Primary Completion Date : | July 30, 2026 |
Estimated Study Completion Date : | December 30, 2028 |

Arm | Intervention/treatment |
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Experimental: Giredestrant + Investigator's Choice of CDK4/6i
Participants in the experimental arm will receive giredestrant plus the investigator's choice of CDK4/6 inhibitor (CDK4/6i): palbociclib, ribociclib, or abemaciclib.
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Drug: Giredestrant
Giredestrant 30 milligrams (mg) orally (PO) once a day (QD) on Days 1-28 of each 28-day cycle until progressive disease (PD) or unacceptable toxicity.
Other Names:
Drug: Abemaciclib If chosen by the investigator as the CDK4/6i, participants will receive abemaciclib 150 mg PO twice per day (BID) on Days 1-28 of each 28-day cycle until PD or unacceptable toxicity. Drug: Palbociclib If chosen by the investigator as the CDK4/6i, participants will receive palbociclib 125 mg PO QD on Days 1-21 of each 28-day cycle until PD or unacceptable toxicity. Drug: Ribociclib If chosen by the investigator as the CDK4/6i, participants will receive ribociclib 600 mg PO QD on Days 1-21 of each 28-day cycle until PD or unacceptable toxicity. Drug: LHRH Agonist Only pre/perimenopausal female participants and male participants will receive a luteinizing hormone-releasing hormone (LHRH) agonist locally approved for use in breast cancer on Day 1 of each 28-day treatment cycle. Diagnostic Test: FoundationOne Liquid CDx Assay (F1LCDx) F1LCDx is a next-generation sequencing (NGS)-based in vitro diagnostic test that detects and analyses genomic alterations in circulating cell-free DNA (cfDNA) isolated from plasma derived from the anti-coagulated peripheral whole blood of cancer patients. It will be used to determine the eligibility of participants requiring confirmation of ESR1 mutation status (mutation detected [ESR1m] vs. no mutation detected [ESR1nmd]).
Other Name: F1LCDx |
Active Comparator: Fulvestrant + Investigator's Choice of CDK4/6i
Participants in the control arm will receive fulvestrant plus the investigator's choice of CDK4/6 inhibitor (CDK4/6i): palbociclib, ribociclib, or abemaciclib.
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Drug: Fulvestrant
Fulvestrant 500 mg intramuscularly (IM) on Days 1 and 15 of Cycle 1 and on Day 1 of each subsequent 28-day cycle until PD or unacceptable toxicity. Drug: Abemaciclib If chosen by the investigator as the CDK4/6i, participants will receive abemaciclib 150 mg PO twice per day (BID) on Days 1-28 of each 28-day cycle until PD or unacceptable toxicity. Drug: Palbociclib If chosen by the investigator as the CDK4/6i, participants will receive palbociclib 125 mg PO QD on Days 1-21 of each 28-day cycle until PD or unacceptable toxicity. Drug: Ribociclib If chosen by the investigator as the CDK4/6i, participants will receive ribociclib 600 mg PO QD on Days 1-21 of each 28-day cycle until PD or unacceptable toxicity. Drug: LHRH Agonist Only pre/perimenopausal female participants and male participants will receive a luteinizing hormone-releasing hormone (LHRH) agonist locally approved for use in breast cancer on Day 1 of each 28-day treatment cycle. Diagnostic Test: FoundationOne Liquid CDx Assay (F1LCDx) F1LCDx is a next-generation sequencing (NGS)-based in vitro diagnostic test that detects and analyses genomic alterations in circulating cell-free DNA (cfDNA) isolated from plasma derived from the anti-coagulated peripheral whole blood of cancer patients. It will be used to determine the eligibility of participants requiring confirmation of ESR1 mutation status (mutation detected [ESR1m] vs. no mutation detected [ESR1nmd]).
Other Name: F1LCDx |
- Progression-Free Survival (PFS) in the ESR1 mutation (ESR1m) Subgroup [ Time Frame: From randomization to first occurrence of progressive disease (PD) or death (up to 5 years) ]PFS is defined as the time from randomization to the first occurrence of PD, as determined by the investigator according to Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1), or death from any cause during the study.
- PFS in the Full Analysis Set (FAS) Population [ Time Frame: From randomization to first occurrence of PD or death (up to 5 years) ]
- PFS in the ESR1 no-mutation-detected (ESR1nmd) Subgroup [ Time Frame: From randomization to first occurrence of PD or death (up to 5 years) ]
- Overall Survival (OS) [ Time Frame: From randomization until death from any cause (up to 5 years) ]OS is defined as the time from randomization to death from any cause. It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- Confirmed Objective Response Rate (cORR) [ Time Frame: From randomization until treatment discontinuation (up to 5 years) ]The cORR is defined as the percentage of participants with a complete response (CR) or partial response (PR) on two consecutive occasions at least 4 weeks apart, as determined by the investigator according to RECIST v1.1. It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- Duration of Response (DOR) [ Time Frame: From the first occurrence of a documented objective response to PD or death (up to 5 years) ]DOR is defined as the time from the first occurrence of a documented objective response to PD, as determined by the investigator according to RECIST v1.1, or death from any cause (whichever occurs first). It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- Clinical Benefit Rate (CBR) [ Time Frame: From randomization until treatment discontinuation (up to 5 years) ]The CBR is defined as the percentage of participants with stable disease for at least (≥)24 weeks or a CR or PR, as determined by the investigator according to RECIST v1.1. It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- Time to Chemotherapy [ Time Frame: From randomization until the start of chemotherapy or death (up to 5 years) ]Time to chemotherapy is defined as the time from randomization until the start date of the first chemotherapy or death from any cause (whichever occurs first). It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- Time to Confirmed Deterioration (TTCD) in Pain Severity [ Time Frame: From randomization until end of follow-up (up to 5 years) ]TTCD in pain severity is defined as the time from randomization to the first documentation of ≥2-point increase from baseline on the "worst pain" item score of the Brief Pain Inventory-Short Form (BPI-SF). It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- TTCD in Pain Presence and Interference [ Time Frame: From randomization until end of follow-up (up to 5 years) ]TTCD in pain presence and interference is defined as the time from randomization to the first documentation of ≥10-point increase in pain score, as determined using the European Organisation for Research and Treatment of Cancer Quality of Life-Core 30 (EORTC QLQ-C30) questionnaire. It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- TTCD in Physical Functioning [ Time Frame: From randomization until end of follow-up (up to 5 years) ]TTCD in physical functioning (PF) is defined as the time from randomization to the first documentation of ≥10-point decrease in PF score, as determined using the EORTC QLQ-C30 questionnaire. It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- TTCD in Role Functioning [ Time Frame: From randomization until end of follow-up (up to 5 years) ]TTCD in role functioning (RF) is defined as the time from randomization to the first documentation of ≥10-point decrease in RF score, as determined using the EORTC QLQ-C30 questionnaire. It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- TTCD in Global Health Status/Quality of Life [ Time Frame: From randomization until end of follow-up (up to 5 years) ]TTCD in in Global Health Status/Quality of Life (GHS/QoL) is defined as the time from randomization to the first documentation of ≥10-point decrease in GHS/QoL score, as determined using the EORTC QLQ-C30 questionnaire. It will be analyzed in the FAS and in the ESR1m and ESR1nmd subgroups.
- Incidence and Severity of Adverse Events [ Time Frame: From Baseline until 28 days after the final dose of study treatment (up to 5 years) ]Incidence will be reported as the number of participants with at least one adverse event, with severity determined according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 5 (NCI CTCAE v5.0).
- Number of Participants with Vital Sign Abnormalities Over the Course of the Study [ Time Frame: From Baseline until 28 days after the final dose of study treatment (up to 5 years) ]Vital signs include respiratory rate, pulse rate, systolic and diastolic blood pressure, and temperature.
- Number of Participants with Clinical Laboratory Test Abnormalities for Hematology and Biochemistry Parameters Over the Course of the Study [ Time Frame: From Baseline until 28 days after the final dose of study treatment (up to 5 years) ]

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Locally advanced or metastatic adenocarcinoma of the breast, not amenable to treatment with curative intent
- Documented estrogen receptor-positive (ER+), HER2-negative (HER2-) tumor assessed locally on the most recent tumor biopsy (or archived tumor sample)
- Confirmed ESR1 mutation status (ESR1m vs. ESR1nmd) in baseline circulating tumor DNA (ctDNA) through central laboratory testing
- Resistance to prior adjuvant endocrine therapy (ET). Prior use of neo/adjuvant CDK4/6i is allowed.
- No prior systemic anti-cancer therapy for advanced disease
- Measurable disease as defined per RECIST v.1.1 or non-measurable bone-only disease
- Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0-1
- For pre/perimenopausal women and for men: treatment with LHRH agonist therapy (as per local guidelines) for the duration of study treatment is required
Exclusion Criteria:
- Prior systemic therapy (e.g., prior chemotherapy, immunotherapy, or biologic therapy) for locally advanced unresectable or metastatic breast cancer
- Prior treatment with another SERD (e.g., fulvestrant, oral SERDs) or novel ER-targeting agents
- Advanced, symptomatic, visceral spread that is at risk of life-threatening complications in the short term
- Active cardiac disease or history of cardiac dysfunction
- Clinically significant history of liver disease

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT06065748
Contact: Reference Study ID Number: CO44657 https://forpatients.roche.com/ | 888-662-6728 (U.S. Only) | global-roche-genentech-trials@gene.com |
United States, Maryland | |
Frederick Health Hospital | Recruiting |
Frederick, Maryland, United States, 21701 | |
Canada, Ontario | |
Royal Victoria Regional Health Centre | Recruiting |
Barrie, Ontario, Canada, L4M 6M2 | |
North York General Hospital | Recruiting |
Toronto, Ontario, Canada, M2K 1E1 | |
Canada, Quebec | |
CHU de Québec - Hôpital du Saint-Sacrement | Recruiting |
Quebec City, Quebec, Canada, G1S 4L8 |
Study Director: | Clinical Trials | Hoffmann-La Roche |
Responsible Party: | Hoffmann-La Roche |
ClinicalTrials.gov Identifier: | NCT06065748 |
Other Study ID Numbers: |
CO44657 2022-502980-39-00 ( Registry Identifier: EU CT Number ) |
First Posted: | October 4, 2023 Key Record Dates |
Last Update Posted: | November 7, 2023 |
Last Verified: | November 2023 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | For eligible studies, qualified researchers may request access to individual patient level data through the request platform (www.vivli.org). Further details on Roche's criteria for eligible studies are available here (https://vivli.org/ourmember/roche/). For further details on Roche's Global Policy on the Sharing of Clinical Information and how to request access to related clinical study documents, see here (https://www.roche.com/innovation/process/clinical-trials/data-sharing/). |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | Yes |
oral Selective Estrogen Receptor Degrader (SERD) CDK4/6 inhibitor (CDK4/6i) ESR1 mutation |
Breast Neoplasms Neoplasms by Site Neoplasms Breast Diseases Skin Diseases Fulvestrant Palbociclib Antineoplastic Agents, Hormonal Antineoplastic Agents |
Estrogen Receptor Antagonists Estrogen Antagonists Hormone Antagonists Hormones, Hormone Substitutes, and Hormone Antagonists Physiological Effects of Drugs Protein Kinase Inhibitors Enzyme Inhibitors Molecular Mechanisms of Pharmacological Action |