A Study of a Medicine Called Atirmociclib in Combination With Giredestrant in Adult Participants With ER-positive, HER2-negative Early-stage Breast Cancer

November 5, 2026 updated by: Pfizer

AN INTERVENTIONAL, DOUBLE-BLIND, PLACEBO CONTROLLED, RANDOMIZED, MULTICENTER PHASE 3 STUDY OF ATIRMOCICLIB (PF-07220060) PLUS GIREDESTRANT COMPARED TO GIREDESTRANT MONOTHERAPY AS ADJUVANT TREATMENT IN ADULT PARTICIPANTS WITH ESTROGEN RECEPTOR (ER)-POSITIVE, HER2-NEGATIVE EARLY-STAGE BREAST CANCER WITH MEDIUM OR HIGH RISK OF RECURRENCE (FOURLIGHT-4)

This Phase 3 study will evaluate whether atirmociclib plus giredestrant improves invasive breast cancer-free survival compared with giredestrant alone in adults with ER-positive, HER2-negative early breast cancer at medium or high risk of recurrence.

This is a Phase 3, double blind, placebo controlled study of atirmociclib plus giredestrant vs. giredestrant monotherapy as adjuvant treatment in adult patients with ER+, HER2- early breast cancer. The study plans to enroll 3800 participants randomized 1:1 into one of two treatment arms (Arm A - investigational: atirmociclib plus giredestrant taken continuously in a 28-day cycle) or (Arm B - comparator: placebo plus giredestrant taken continuously in a 28-day cycle). Participants may be treated with atirmociclib/placebo up to 3 years and giredestrant up to 5 years followed by long term follow up for survival and evaluation of recurrence of disease.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
3800

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

KEY INCLUSION CRITERIA

  1. Histologically confirmed unilateral primary adenocarcinoma of the breast

    • ER-positive by local assessment
    • documented HER2-negative

  2. Node positive or node negative as defined by:

    • Pathological node positive (microscopic and/or macroscopic tumor involvement >/=pN1)

    • pN0 and pT >1cm with at least one of the following:

      1. pT4N0 or
      2. histologically Grade 3 disease or
      3. high-risk classification based on genomic assay

  3. Randomization within 16 months of definitive breast surgery

  4. If indicated, completed adjuvant and/or neoadjuvant chemotherapy, adjuvant radiation therapy >/= 21 days prior to randomization

KEY EXCLUSION CRITERIA

  1. Distant metastases of breast cancer beyond regional lymph nodes

  2. Multicentric or multifocal breast cancer if any tumor foci meet pathologic criteria for ER(-) or HER2(+)

  3. Clinically significant cardiovascular disease or cardiac repolarization abnormality for 6 months prior to randomization; resting heart rate <50bpm

  4. Has received the following prior systemic anti-cancer therapy for breast cancer

    • prior atirmociclib, giredestrant, other investigational anti-cancer agent
    • prior treatment with olaparib

    NOTES:

    • short course of prior neo/adjuvant CDK4/6 inhibitor treatment (</=8 weeks) is permitted; 10-day washout period required
    • short course of prior neoadjuvant and/or adjuvant ET (</=18 weeks) is permitted; 35-day washout period for tamoxifen is required

  5. Prior treatment with investigational product within 30 days or 5 half-lives

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Arm A : Atirmociclib + giredestrant

Atirmociclib tablet given orally twice daily, plus giredestrant capsule given orally once per day
Drug: Atirmociclib

Atirmociclib tablet given orally twice daily, plus giredestrant capsule given orally once per day

Other Names:
  • PF-07220060
Drug: giredestrant

giredestrant capsule given once a day
Active Comparator: Arm B: Placebo for atirmociclib + giredestrant

Placebo atirmociclib tablets given orally twice a day plus giredestrant capsule given once a day
Drug: giredestrant

giredestrant capsule given once a day

Other: Atirmociclib placebo

Atirmociclib placebo tablet given twice a day

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Invasive Breast Cancer Free Survival (iBCFS)
Time Frame: From randomization to first iBCFS event, up to 16 years

iBCFS is defined as the time from the date of randomization to the date of first documented occurrence of invasive ipsilateral breast tumor recurrence, local-regional invasive breast cancer recurrence, invasive contralateral breast cancer, distant recurrence, or death from any cause, as determined by investigator assessment per STEEP v2.0 criteria
From randomization to first iBCFS event, up to 16 years

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Invasive Disease Free Survival (iDFS)
Time Frame: From randomization to first iDCFS event, up to 16 years

iDFS defined as the time from the date of randomization to the date of first documented occurrence of invasive ipsilateral breast tumor recurrence, local-regional invasive breast cancer recurrence, invasive contralateral breast cancer, distant recurrence, second primary invasive non-breast cancer, or death from any cause, as determined by investigator assessment per STEEP v2.0 criteria
From randomization to first iDCFS event, up to 16 years
Disease Recurrence Free Survival (DRFS)
Time Frame: From randomization to first DRFS event, up to 16 years

DRFS as per investigator assessment, defined as the time from the date of randomization to the date of distant recurrence as determined by investigator assessment or death from any cause, whichever occurs first
From randomization to first DRFS event, up to 16 years
Overall survival (OS)
Time Frame: From randomization to death from any cause, up to 16 years

OS is defined as the time from the date of randomization to the date of death due to any cause
From randomization to death from any cause, up to 16 years
Number and percentage of Participants with Treatment-Emergent Adverse Events (AEs)
Time Frame: From start of treatment until 28 days after last dose of study treatment, up to 5 years

Type, incidence, severity of AE graded by NCI CTCAE v 5.0, seriousness and relationship to study intervention
From start of treatment until 28 days after last dose of study treatment, up to 5 years
Percentage of participants With Clinical Laboratory Abnormalities
Time Frame: From start of treatment until 28 days after last dose of study treatment, up to 5 years
From start of treatment until 28 days after last dose of study treatment, up to 5 years
Percentage of Participants With ECG abnormalities
Time Frame: From start of treatment until 28 days after last dose of study treatment, up to 5 years
From start of treatment until 28 days after last dose of study treatment, up to 5 years
Patient Reported Outcomes (PRO)
Time Frame: From start of treatment until 28 days after last dose of study treatment, up to 5 years

Change from baseline in participant reported total score, well-being subscales and symptoms scores and TOI per FACT-ES
From start of treatment until 28 days after last dose of study treatment, up to 5 years
Pre-dose Plasma Concentration (Ctrough) of atirmociclib
Time Frame: Cycle 1 Day 15, Cycle 2 Day 1, and Cycle 3 Day 1; Cycle is defined as 28 days
Cycle 1 Day 15, Cycle 2 Day 1, and Cycle 3 Day 1; Cycle is defined as 28 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Pfizer

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 13, 2032

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 20, 2042

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 16, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 16, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
October 22, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 10, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 5, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • C4391026

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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