AzTrials
AzTrials

Metastatic Breast CancerNCT05361655

Real-World Effectiveness of Palbociclib in Combination With an Aromatase Inhibitor

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

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

A retrospective study of de-identified (to preserve patient privacy) patient information from the Flatiron Health Analytic Database to compare effectiveness (i.e., overall survival) of first line palbociclib + aromatase inhibitor (AI) versus AI alone treatment in postmenopausal women or men with hormone receptor… Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Metastatic Breast Cancer
What is being tested?
Palbociclib + an aromatase inhibitor and Aromatase inhibitor
How many people
2,888 participants
Where
1 siteUnited States
Study dates
1 Sep 2021to 1 Sep 2021
Phase
Observational
Are there results?
Yes, posted in the registrySummary in the doctors' view

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: HR+/HER2- MBC adult patients treated with Palbociclib + AI or AI alone between February2015 and September, 2020

Who may be able to join

  • Confirmed HR+/HER2- status after MBC diagnosis.
  • Received palbociclib + AI or AI as first-line therapy

Who cannot join

  • Evidence of prior treatment with other CDK4/6I, AI, tamoxifen, raloxifene, toremifene, or Fulvestrant for MBC
  • First structured activity greater than 90 days after MBC diagnostic date
  • Treatment with a CDK4/6 inhibitor as part of a clinical trial

Trial locations and contacts

1 site in 1 country.

United States1 site

  • 10017

    New York, New York, 10017

Other trials in United States

About this study

Official title: Real-World Treatment Effectiveness of Palbociclib in Combination With an Aromatase Inhibitor as 1st Line Therapy in Metastatic Breast Cancer

A retrospective study of de-identified (to preserve patient privacy) patient information from the Flatiron Health Analytic Database to compare effectiveness (i.e., overall survival) of first line palbociclib + aromatase inhibitor (AI) versus AI alone treatment in postmenopausal women or men with hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) metastatic breast cancer (MBC) in the United States clinical practices.

Being tested
Palbociclib + an aromatase inhibitor, Aromatase inhibitor
Keywords
cyclin-dependent kinase 4/6i (CDK4/6i)
Medical subject headings
Breast Neoplasms

What participants receive

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

  • Palbociclib + an aromatase inhibitorDrug

    Palbociclib + an aromatase inhibitor therapy

  • Aromatase inhibitorDrug

    Aromatase inhibitor therapy

Study groups in NCT05361655
Study groupRoleWhat they receive
Palbociclib + an aromatase inhibitorAdult metastatic breast cancer patients who initiated Palbociclib + an aromatase inhibitor as first line therapy between Feb 3, 2015 to March 31, 2020 in the Flatiron Health Analytic Database.
Receives: Drug: Palbociclib + an aromatase inhibitor
Aromatase inhibitorAdult metastatic breast cancer patients who initiated an aromatase inhibitor as first line therapy between Feb 3, 2015 to March 31, 2020 in the Flatiron Health Analytic Database.
Receives: Drug: Aromatase inhibitor

What is being measured

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

  1. Overall Survival (OS) in Postmenopausal Female or Male Participants With Metastatic Breast Cancer

    OS was defined as the time from the index date (start of palbociclib + AI or AI alone) to death. Participants who did not die, were censored at the end of study date (30-Sep-2020). Kaplan-Meier method adjusted by stabilized inverse probability of treatment weighting (sIPTW) was used.

    Measured: From index date to death due to any cause or censoring date of 30-Sep-2020 (approximately up to 68 months)

Secondary outcomes (9)

  1. Real-World Progression Free Survival (rwPFS) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer

    Real-world PFS was defined as the number of months from start of palbociclib + AI or AI alone to death from any cause or disease progression (based on clinical assessment or by radiographic scan/tissue biopsy), whichever occurred first. Disease progression was defined as at least a 20 percentage (%) increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that was the smallest on study). Participants who did not die and did not have disease progression were censored at the date of initiation of next line of therapy for participants with 2 or more lines of therapy or at the date of their last visit during the study period (February 2015-September 2020) for participants with only 1 line of therapy. Kaplan-Meier method adjusted by stabilized IPTW was used.

    Measured: From index date until disease progression or death due to any cause or censoring date (approximately up to 68 months)

  2. Number of Participants According to Real-World Tumor Responses (rwTR): Postmenopausal Female or in Male Participants With Metastatic Breast Cancer

    Real-world best responses were assessed based on treating clinician's assessment of radiological evidence for change in burden of disease over course of treatment after 1 month of index treatment initiation. Responses were classified as complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD), indeterminate response (IR). CR=Complete resolution of all visible disease. PR=partial reduction in size of visible disease in some or all areas without any areas of increase in visible disease. SD=no change in overall size of visible disease. PD: an increase in visible disease; also included cases where some lesions increased in size and some lesions decreased in size; included cases where clinician indicated progressive disease; IR=study data not available for evaluation of efficacy for any reason, including participants lost to follow-up or assessment not undertaken or death. Analysis was performed using sIPTW method to balance participant characteristics.

    Measured: From 30 days after index treatment initiation until CR, PR, SD or PD (approximately 67 months)

  3. Real-World Response Rate (rwTR) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer

    Real-world tumor response rate (rwTR) was defined as the percentage of participants with a real world complete response (rwCR) or real-world partial response (rwPR). CR: complete resolution of all visible disease. PR: partial reduction in size of visible disease in some or all areas without any areas of increase in visible disease. Analysis was performed using sIPTW method to balance participant characteristics.

    Measured: From 30 days after index treatment initiation until disease progression or death due to any cause or censoring date (approximately up to 67 months)

  4. Number of Participants According to Initial Dose of Palbociclib: Palbociclib + Aromatase Inhibitor Arm Only

    Number of participants according to the initial dose of palbociclib (75 milligrams [mg]/day, 100mg/day, 125 mg/day or missing dose) are reported in this outcome measure.

    Measured: At index (anytime between 03-Feb-2015 to 31-Mar-2020, approximately up to 62 months)

  5. Time to Dose Adjustment for Palbociclib- Palbociclib + Aromatase Inhibitor Arm Only

    Time to dose adjustment for participants who received palbociclib 125 mg/day, 100 mg/day, or 75 mg/day as initial dose was presented in this outcome measure.

    Measured: At index (anytime between 03-Feb-2015 to 30-Sep-2020, approximately up to 68 months)

  6. Duration of Treatment

    Duration of treatment was defined as days from index prescription order date to end of treatment, start of subsequent line of therapy, or death from any cause, whichever occurred first. Kaplan-Meier method adjusted by stabilized IPTW was used.

    Measured: From start of study treatment to end of treatment, start of subsequent line of therapy, or death from any cause, whichever occurred first (up to 68 months)

  7. Time to Next Line of Treatment

    Time to next line of treatment represents the interval from commencement of one treatment to initiation of the next line of therapy. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups.

    Measured: From start of study treatment to start of next line of therapy (up to 68 months)

  8. Time to Subsequent Chemotherapy

    Time to subsequent chemotherapy represents the time interval to administration of a different chemotherapeutic agent after the first course of therapy was administered. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups.

    Measured: From start of study treatment to administration of different chemotherapeutic agent (up to 68 months)

  9. Real-World Progression Free Survival 2 (rwPFS2) in Postmenopausal Female or in Male Participants With Metastatic Breast Cancer

    rwPFS2 was defined as the time from the index date to the date of the first documentation of a rwPD or death due to any cause after starting second line of therapy, whichever occurs first. Disease progression was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study (this includes the baseline sum if that was the smallest on study). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. Analysis was performed using sIPTW method to balance participant characteristics among reporting groups.

    Measured: From start of study treatment until disease progression, or death from any cause following second line of therapy, whichever occurred first (approximately up to 68 months)

Timeline

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

  1. First posted5 May 2022
  2. Study start1 Sep 2021
  3. Primary completion1 Sep 2021
  4. Study completion1 Sep 2021

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
2,888 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05361655
Sponsor's protocol ID
A5481151
Status last verified
May 2024
First submitted
21 Apr 2022
Last updated
7 Jun 2024
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, Liu X, Li B, McRoy L, Chen C, Makari D, Layman RM, Brufsky A. Treatment outcomes with palbociclib plus an aromatase inhibitor in patients with metastatic breast cancer who also have cardiovascular diseases: a plain language summary. Future Oncol. 2026 Jun;22(14):1613-1623. doi: 10.1080/14796694.2026.2672130. Epub 2026 Jun 21.

    PubMed 42324685

  • Layman RM, Liu X, Li B, McRoy L, Brufsky A. Real-world palbociclib dose modifications and clinical outcomes in patients with HR+/HER2- metastatic breast cancer: A Flatiron Health database analysis. Breast. 2025 Jun;81:104448. doi: 10.1016/j.breast.2025.104448. Epub 2025 Mar 17.

    PubMed 40138984

  • Brufsky A, Liu X, Li B, McRoy L, Chen C, Makari D, Layman RM, Rugo HS. Palbociclib plus aromatase inhibitors in patients with metastatic breast cancer and cardiovascular diseases: real-world effectiveness. Oncologist. 2024 Dec 6;29(12):1032-1043. doi: 10.1093/oncolo/oyae273.

    PubMed 39418346

  • Rugo HS, Liu X, Li B, McRoy L, Chen C, Layman RM, Tomlin-Harris T, Brufsky A. Prolonging the lives of African-Americans with metastatic breast cancer by adding palbociclib to an aromatase inhibitor in routine clinical practice: a plain language summary of a real-world database study. Future Oncol. 2024;20(19):1299-1307. doi: 10.2217/fon-2023-1079. Epub 2024 Mar 22.

    PubMed 38517416

  • Rugo HS, Liu X, Li B, McRoy L, Chen C, Layman RM, Brufsky A. Real-World Effectiveness of Palbociclib Plus Aromatase Inhibitors in African American Patients With Metastatic Breast Cancer. Oncologist. 2023 Oct 3;28(10):866-874. doi: 10.1093/oncolo/oyad209.

    PubMed 37487056

  • Rugo HS, Brufsky A, Liu X, Li B, McRoy L, Chen C, Layman RM, Cristofanilli M, Torres MA, Curigliano G, Finn RS, DeMichele A. Prolonging the life of people with metastatic breast cancer in routine clinical practice by adding palbociclib to an aromatase inhibitor from a real-world database analysis: a plain language summary. Future Oncol. 2023 Mar;19(7):489-498. doi: 10.2217/fon-2022-1192. Epub 2023 Mar 9.

    PubMed 36892508

  • Rugo HS, Brufsky A, Liu X, Li B, McRoy L, Chen C, Layman RM, Cristofanilli M, Torres MA, Curigliano G, Finn RS, DeMichele A. Real-world study of overall survival with palbociclib plus aromatase inhibitor in HR+/HER2- metastatic breast cancer. NPJ Breast Cancer. 2022 Oct 11;8(1):114. doi: 10.1038/s41523-022-00479-x.

    PubMed 36220852

Questions about this trial

What is this clinical trial studying?

An observational study of Metastatic Breast Cancer, 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?

The sponsor lists 2 inclusion and 3 exclusion criteria. 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: finished, as of the sponsor's last update on 7 Jun 2024. 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?

Yes. Results are posted in the registry (first posted 7 Jun 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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) in Postmenopausal Female or Male Participants With Metastatic Breast Cancer (time frame: From index date to death due to any cause or censoring date of 30-Sep-2020 (approximately up to 68 months)). 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 NCT05361655, which also lists 7 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 7 Jun 2024.

AzTrials uses cookies for analytics and advertising. You can accept or reject them; the site works either way. Privacy Policy.

Free account

Log in to keep searching

You’ve used your 3 free searches. AzTrials is free: log in or create a free account to keep searching clinical trials and save the ones you want to follow.

Create a free accountLog in