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Breast CancerNCT06495164

A Real-life Study to Understand the Use and Effects of Palbociclib in US Patients With Breast Cancer

An observational study of Breast Cancer and Malignant Neoplasm of Breast, run by Pfizer at 1 site in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

Palbociclib, the first oral CDK4/6 inhibitor, is an approved medicine indicated for the treatment of a kind of advanced/metastatic breast cancer (MBC), called hormone receptors positive (HR+)/ Human epidermal growth factor receptor 2 negative (HER2-) disease. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Breast Cancer, Malignant Neoplasm of Breast
What is being tested?
Palbociclib, Aromatase inhibitor and Ribociclib
Type of treatment
Pill or oral medicine
How many people
1 participants
Where
1 siteUnited States
Study dates
24 Jun 2024to 30 Dec 2026
Phase
Observational
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: Flatiron Health Database is a longitudinal, demographically, and geographically diverse dataset derived from EHR data from over 280 cancer clinics (~800 sites of care) including more than 3.0 million active US cancer patients available for analysis. This study uses secondary de-identified Flatiron Health data that involve men and women who had been diagnosed with HR+/HER2-MBC in the United States.

Patients are eligible for the study if they were 18 years of age or older at MBC diagnosis, had HR+/HER2- confirmed and initiated first line therapy (CDK4/6i, ET, CT, or other) in the metastatic setting during the period from February 2015 through June 2022 or data cutoff.

Trial locations and contacts

1 site in 1 country.

United States1 site

  • Pfizer New York

    New York, New York, 10001

Other trials in United States

About this study

Official title: Palbociclib Treatment Patterns and Outcomes in HR+/HER2- MBC: Flatiron Database Analysis

Palbociclib, the first oral CDK4/6 inhibitor, is an approved medicine indicated for the treatment of a kind of advanced/metastatic breast cancer (MBC), called hormone receptors positive (HR+)/ Human epidermal growth factor receptor 2 negative (HER2-) disease. Palbociclib is given orally in combination with hormonal therapies.

The purpose of this study is to better understand how Palbociclib combination is used in real-life conditions and its clinical impact compared with hormonal therapy. The study will also evaluate how long patients take the different CDK 4/6 inhibitor drugs and whether using those drugs impacts the use of chemotherapy later.

Read more

Male and female patients aged 18 years old or more presenting the following conditions will be selected for the study:

  • HR+/HER2- MBC
  • First treatment with Palbociclib, hormonal therapy, or other CDK4/6 inhibitors after MBC diagnosis The study will use data without personal identity, which were obtained from medical records in routine clinical practice.
Being tested
Palbociclib, Aromatase inhibitor, Ribociclib, Abemaciclib
Keywords
Metastatic breast cancer, CDK4/6 inhibitor, Real-world data, Retrospective observational study, Palbociclib, Overall survival
Medical subject headings
Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • PalbociclibDrug

    Also called Ibrance

    CDK4/6 inhibitor

  • Aromatase inhibitorDrug

    Also called a class of drugs included in the study: letrozole (Femara), anastrozole (Arimidex), and exemestane (Aromasin)

    Aromatase inhibitor

  • RibociclibDrug

    Also called Kisqali

    CDK4/6 inhibitor

  • AbemaciclibDrug

    Also called Verzenio

    CDK4/6 inhibitor

Study groups in NCT06495164
Study groupRoleWhat they receive
Palbociclib + aromatase inhibitor (AI)Oral palbociclib + AI combination treatment regimen as decided by physician
Receives: Drug: Palbociclib; Drug: Aromatase inhibitor
Aromatase inhibitor (AI)Oral AI treatment regimen as decided by physician
Receives: Drug: Aromatase inhibitor
Abemaciclib plus aromatase inhibitor (AI)Oral abemaciclib plus AI treatment regimen as decided by physician
Receives: Drug: Palbociclib; Drug: Aromatase inhibitor; Drug: Abemaciclib
Ribociclib plus aromatase inhibitor (AI)Oral ribociclib plus AI as decided by physician
Receives: Drug: Aromatase inhibitor; Drug: Ribociclib

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Overall Survival (OS)

    Measured: From start of index line of therapy to death, February 2015 - December 2022 or data cutoff

Secondary outcomes (5)

  1. Real Progression Free Survival (rwPFS)

    Measured: From start of index line of therapy to death or disease progression, February 2015 - December 2022 or data cutoff

  2. Progression Free Survival 2

    Measured: from start of index treatment to disease progression on the 2nd line of therapy or death, February 2015 - December 2022 or data cutoff

  3. Real-World Tumor Response (rwTR)

    Measured: From start of index treatment to tumor response, February 2015 - December 2022 or data cutoff

  4. Duration of treatment

    Measured: from index treatment initiation to end of the treatment, February 2015 - December 2022 or data cutoff

  5. Time to chemotherapy

    Measured: from index treatment initiation to subsequent chemotherapy, February 2015 - December 2022 or data cutoff

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted10 Jul 2024
  2. Study start24 Jun 2024
  3. Primary completion30 Dec 2026 (estimated)
  4. Study completion30 Dec 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Retrospective
Enrolment
1 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06495164
Sponsor's protocol ID
A5481189
Other IDs
NCT06495164
Status last verified
Nov 2025
First submitted
3 Jul 2024
Last updated
25 Nov 2025
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No: 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.

Publications

  • Rugo HS, Layman RM, Lynce F, Liu X, Li B, McRoy L, Cohen AB, Estevez M, Curigliano G, Brufsky A. Comparison of survival outcomes for people with HR+/HER2- metastatic breast cancer who received palbociclib, ribociclib, or abemaciclib with an aromatase inhibitor: a plain language summary. Future Oncol. 2026 Jun;22(14):1625-1635. doi: 10.1080/14796694.2026.2674970. Epub 2026 Jun 21.

    PubMed 42324670

  • Brufsky A, Layman RM, Liu X, Li B, McRoy L, Cohen A, Estevez M, Cottu P, Thill M, Curigliano G, Rugo HS. Real-world treatment durations, subsequent treatments, and switching of CDK4/6 inhibitors among patients with HR+/HER2- metastatic breast cancer. Oncologist. 2026 May 8;31(6):oyag182. doi: 10.1093/oncolo/oyag182.

    PubMed 42095602

  • Rugo HS, Brufsky A, Layman RM, Liu X, Li B, McRoy L, Cohen AB, Estevez M, Lynce F, Cottu P, Thill M, Curigliano G. Real-world progression-free survival 2 (PFS2) and tumor response of CDK4/6 inhibitors plus an aromatase inhibitor in patients with HR+/HER2- metastatic breast cancer in US routine clinical practice. Breast. 2026 Jun;87:104780. doi: 10.1016/j.breast.2026.104780. Epub 2026 Mar 30.

    PubMed 41950642

  • Brufsky A, Layman RM, Liu X, Li B, McRoy L, Cohen AB, Estevez M, Cottu P, Curigliano G, Rugo HS. Real-world effectiveness of palbociclib in combination with an aromatase inhibitor in HR+/HER2- bone-only metastatic breast cancer. Breast. 2026 Apr;86:104744. doi: 10.1016/j.breast.2026.104744. Epub 2026 Feb 24.

    PubMed 41830752

  • Lynce F, Liu X, Li B, McRoy L, Chen C, Liu R, Rugo HS. Real-world effectiveness of palbociclib plus an aromatase inhibitor in HR+/HER2- MBC patients living in disadvantaged neighborhoods. NPJ Breast Cancer. 2025 Jul 21;11(1):75. doi: 10.1038/s41523-025-00786-z.

    PubMed 40691446

Questions about this trial

What is this clinical trial studying?

An observational study of Breast Cancer and Malignant Neoplasm of Breast, run by Pfizer at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 25 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Overall Survival (OS) (time frame: From start of index line of therapy to death, February 2015 - December 2022 or data cutoff). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06495164, which also lists 5 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Nov 2025.

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Clinical Trial NCT06495164 | AzTrials