Advanced Breast CancerNCT07178743
Emulation of the PALOMA-2 Trial
An observational study of Advanced Breast Cancer, run by Brigham and Women's Hospital at 1 site in United States.
Trial summary
Investigators are building an empirical evidence base for real world data through large-scale emulation of randomized controlled trials. The investigators' goal is to understand for what types of clinical questions real world data analyses can be conducted with confidence and how to implement such studies. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Advanced Breast Cancer
- What is being tested?
- Initiation of palbociclib plus letrozole and Initiation of letrozole
- How many people
- 6,097 participants
- Where
- 1 siteUnited States
- Study dates
- 14 Jul 2025to 1 Mar 2026
- Phase
- Observational
- Are there results?
- None posted in the registry
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
- Women only
- No healthy volunteers
- Adult, Older adult
Study population: Postmenopausal women with ER-positive, HER2-negative locally advanced or metastatic breast cancer who receive treatment without curative intent
Who may be able to join
- Age ≥18 years
- Postmenopausal women with ER-positive, HER2-negative locally advanced or metastatic breast cancer who receive treatment without curative intent
- The line of therapy for patients in EDB1 and EDB3 is implicitly advanced/metastatic because the line of therapy classification starts after their advanced/metastatic diagnosis in the respective database
- In EDB4, patients must explicitly have any evidence of a metastasis prior initiating palbociclib plus letrozole or letrozole alone
- Adenocarcinoma histology
- No prior systemic treatment for advanced/metastatic disease
- ECOG performance status of 0 or 1
Who cannot join
- HER2+
- CNS metastases
- Prior treatment with CDK4/6 inhibitor
- Non-breast cancer malignancy other than basal/squamous cell skin cancer or carcinoma in situ of cervix
- Systemic anticancer therapy other than palbocicilib or letrozole
- Treatment with non-steroidal aromatase inhibitor (i.e.anastrozole, letrozole)
Trial locations and contacts
1 site in 1 country.
United States1 site
Brigham and Women's Hospital
Boston, Massachusetts, 02120
About this study
Investigators are building an empirical evidence base for real world data through large-scale emulation of randomized controlled trials. The investigators' goal is to understand for what types of clinical questions real world data analyses can be conducted with confidence and how to implement such studies.
Read the detailed description
Randomized controlled trials (RCTs) are generally regarded as the gold-standard of evidence for establishing efficacy of medical products. However, real-world data (RWD) are increasingly used to complement evidence from RCTs. Yet, to have confidence in the accuracy of non-interventional studies medical products and their outcomes in oncology, investigators need to know what questions can be validly answered, with which non-interventional study designs, and which analysis methods are appropriate, given the data that is available. Building on a process from the RCT DUPLICATE initiative. EmulatioN of Comparative Oncology trials with Real-world Evidence (ENCORE) is the trial emulation discussed in this protocol is part of the expansion project specific to oncology and aims to emulate 12 randomized oncology RCTs using multiple EHR data sources.
The purpose of this protocol is to describe the emulation of the PALOMA-2 trial. PALOMA-2 was a Phase III, double-blind, randomized study assessing the efficacy and safety of palbociclib (125 mg orally, once daily for 21 days of a 28-day cycle) in combination with letrozole (2.5 mg orally, once daily, continuously) versus letrozole alone in postmenopausal women with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer who had not received prior systemic treatment for their advanced disease.
- Conditions
- Advanced Breast Cancer
- Being tested
- Initiation of palbociclib plus letrozole, Initiation of letrozole
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Initiation of palbociclib plus letrozoleDrug
Initiation of palbociclib plus letrozole described in electronic health records is used as the exposure.
Initiation of letrozoleDrug
Initiation of letrozole described in electronic health records is used as the reference.
| Study group | Role | What they receive |
|---|---|---|
| Initiation of palbociclib plus letrozole | Exposure group Receives: Drug: Initiation of palbociclib plus letrozole | |
| Initiation of letrozole | Reference group Receives: Drug: Initiation of letrozole |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time to all-cause mortality (overall survival)
Hazard ratio (95% CI)
Measured: Through the earliest of outcome, censoring, or end of data (April 2024)
Secondary outcomes (1)
Time to next treatment (TTNT)
Median overall survival time (difference) in % (95% CI)
Measured: Through the earliest of outcome, censoring, or end of data (April 2024)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Sep 2025
- Study start14 Jul 2025
- Primary completion1 Mar 2026
- Study completion1 Mar 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Advanced Breast CancerStudies of the same condition, open and under way.
- More trials run by Brigham and Women's HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- 6,097 participants (actual)
Sponsor and investigators
- Lead sponsor
- Brigham and Women's Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Food and Drug Administration (FDA)
- Responsible party
- Principal investigator, Shirley Vichy Wang, Brigham and Women's Hospital
- Investigators
- Shirley Wang, PhD, ScM, Principal investigator, Brigham and Women's HospitalDenys Shay, MD, Principal investigator, Brigham and Women's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07178743
- Sponsor's protocol ID
- 2022P002556-ENC-PALOMA2
- Other IDs
- 75F40122C00181
- Status last verified
- Sep 2025
- First submitted
- 8 Sep 2025
- Last updated
- 12 May 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Emulation of the PALOMA-2 Trial
- ClinicalTrials.gov ID
- NCT07178743
- Acronym / sponsor ID
- 2022P002556-ENC-PALOMA2
- Conditions
- Advanced Breast Cancer
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 6,097 participants (actual)
- Lead sponsor
- Brigham and Women's HospitalUniversity, hospital or other
- Collaborators
- Food and Drug Administration (FDA)
- Study start
- 14 Jul 2025 (actual)
- Primary completion
- 1 Mar 2026 (actual)
- Study completion
- 1 Mar 2026 (actual)
- First posted
- 17 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Investigators are building an empirical evidence base for real world data through large-scale emulation of randomized controlled trials. The investigators' goal is to understand for what types of clinical questions real world data analyses can be conducted with confidence and how to implement such studies.
Detailed description
Randomized controlled trials (RCTs) are generally regarded as the gold-standard of evidence for establishing efficacy of medical products. However, real-world data (RWD) are increasingly used to complement evidence from RCTs. Yet, to have confidence in the accuracy of non-interventional studies medical products and their outcomes in oncology, investigators need to know what questions can be validly answered, with which non-interventional study designs, and which analysis methods are appropriate, given the data that is available. Building on a process from the RCT DUPLICATE initiative. EmulatioN of Comparative Oncology trials with Real-world Evidence (ENCORE) is the trial emulation discussed in this protocol is part of the expansion project specific to oncology and aims to emulate 12 randomized oncology RCTs using multiple EHR data sources.
The purpose of this protocol is to describe the emulation of the PALOMA-2 trial. PALOMA-2 was a Phase III, double-blind, randomized study assessing the efficacy and safety of palbociclib (125 mg orally, once daily for 21 days of a 28-day cycle) in combination with letrozole (2.5 mg orally, once daily, continuously) versus letrozole alone in postmenopausal women with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer who had not received prior systemic treatment for their advanced disease.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Initiation of palbociclib plus letrozole | – | Drug: Initiation of palbociclib plus letrozoleExposure group |
| Initiation of letrozole | – | Drug: Initiation of letrozoleReference group |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Postmenopausal women with ER-positive, HER2-negative locally advanced or metastatic breast cancer who receive treatment without curative intent
Key inclusion criteria (7 listed)
- Age ≥18 years
- Postmenopausal women with ER-positive, HER2-negative locally advanced or metastatic breast cancer who receive treatment without curative intent
- The line of therapy for patients in EDB1 and EDB3 is implicitly advanced/metastatic because the line of therapy classification starts after their advanced/metastatic diagnosis in the respective database
- In EDB4, patients must explicitly have any evidence of a metastasis prior initiating palbociclib plus letrozole or letrozole alone
- Adenocarcinoma histology
Key exclusion criteria (6 listed)
- HER2+
- CNS metastases
- Prior treatment with CDK4/6 inhibitor
- Non-breast cancer malignancy other than basal/squamous cell skin cancer or carcinoma in situ of cervix
- Systemic anticancer therapy other than palbocicilib or letrozole
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Initiation of palbociclib plus letrozoleInitiation of palbociclib plus letrozole described in electronic health records is used as the exposure. | Drug | Initiation of palbociclib plus letrozole |
| Initiation of letrozoleInitiation of letrozole described in electronic health records is used as the reference. | Drug | Initiation of letrozole |
Primary outcome
Time to all-cause mortality (overall survival)
Time frame: Through the earliest of outcome, censoring, or end of data (April 2024)
Hazard ratio (95% CI)
1 secondary outcome
Time to next treatment (TTNT)
Time frame: Through the earliest of outcome, censoring, or end of data (April 2024)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 May 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Shirley Wang, PhD, ScM principal investigator
Brigham and Women's Hospital
Denys Shay, MD principal investigator
Brigham and Women's Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Advanced Breast Cancer, run by Brigham and Women's Hospital 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 7 inclusion and 6 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 12 May 2026. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Time to all-cause mortality (overall survival) (time frame: Through the earliest of outcome, censoring, or end of data (April 2024)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 12 May 2026.