Phase III Study to Assess AZD9833+ CDK4/6 Inhibitor in HR+/HER2-MBC With Detectable ESR1m Before Progression (SERENA-6)

  • End date
    Jun 25, 2026
  • participants needed
  • sponsor
Updated on 24 September 2021
AstraZeneca Clinical Study Information Center
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The study is intended to show superiority of AZD9833 in combination with CDK4/6 inhibitor (palbociclib or abemaciclib) versus aromatase inhibitors (anastrozole or letrozole) in combination with CDK4/6 inhibitor in patients with hormone receptor-positive (HR-positive), human epidermal growth factor receptor 2-negative (HER2-negative) metastatic breast cancer with detectable ESR1 mutation


A Randomised, Multicentre, Double-Blind, Phase III study will evaluate the safety and efficacy of AZD9833 (next generation oral SERD) in combination with CDK4/6 inhibitor (palbociclib or abemaciclib) versus aromatase inhibitor (anastrozole or letrozole) in combination with CDK4/6 inhibitor for the treatment of patients with HR-positive, HER2- negative metastatic breast cancer with detectable ESR1 Mutation. The goal of the study is to demonstrate superiority of AZD9833 over anastrozole or letrozole in the context of combination with palbociclib or abemaciclib

Condition ER-Positive HER2-Negative Breast Cancer, ER-Positive HER2-Negative Breast Cancer, ER-Positive HER2-Negative Breast Cancer, ER-Positive HER2-Negative Breast Cancer, ER-Positive HER2-Negative Breast Cancer, ER-Positive HER2-Negative Breast Cancer, ER-Positive HER2-Negative Breast Cancer, ER-Positive HER2-Negative Breast Cancer
Treatment Letrozole, anastrozole, Palbociclib, Abemaciclib, AZD9833, Anastrozole placebo, AZD9833 placebo, Luteinizing hormone-releasing hormone (LHRH) agonist, Letrozole placebo
Clinical Study IdentifierNCT04964934
Last Modified on24 September 2021


Yes No Not Sure

Inclusion Criteria

Proven diagnosis of adenocarcinoma of the breast with evidence of locoregionally recurrent or metastatic disease not amenable to resection or radiation therapy with curative intent
Documentation of histologically confirmed diagnosis of estrogen receptor positive (ER+) /HER2- breast cancer based on local laboratory results
Currently on AI (letrozole or anastrozole) + CDK4/6 inhibitor (palbociclib or abemaciclib) LHRH as the initial endocrine based treatment for advanced disease
Eastern Cooperative Oncology Group performance status of 0 or 1
ESR1m positive detected by central testing of ctDNA
Willingness and ability to comply with scheduled visits, treatment plan, laboratory tests, and other study procedures
Adequate organ and marrow function

Exclusion Criteria

Advanced, symptomatic, visceral spread, that are at risk of life-threatening complications in the short term
Known active uncontrolled or symptomatic CNS metastases, carcinomatous meningitis, or leptomeningeal disease
Any evidence of severe or uncontrolled systemic diseases which, in the investigator's opinion, makes it undesirable for the participant to participate in the study or that would jeopardize compliance with the protocol
Patient with known or family history of severe heart disease
Previous treatment with AZD9833, investigational SERDs or fulvestrant
Currently pregnant (confirmed with positive pregnancy test) or breastfeeding
Persistent non-haematological toxicities (CTCAE Grade > 2) caused by CDK4/6 inhibitor and/or AI treatment
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