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Advanced Breast CancerNCT07274709

Emulation of the MONALEESA-2 Trial Using Specialty Oncology Electronic Health Records Databases

An observational study of Advanced Breast Cancer, run by Shirley Vichy Wang 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
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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 ribociclib and Initiation of letrozole
How many people
2,495 participants
Where
1 siteUnited States
Study dates
7 Sep 2025to 1 Jan 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 hormone receptor (HR)-positive [estrogen receptor (ER) and/or progesterone receptor (PR)], human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer.

Who may be able to join

  • Age ≥18 years through 2017 to 2023
  • Metastatic breast cancer
  • Hormone receptor positive (ER/PR+)
  • Untreated with systemic anticancer therapy for advanced disease
  • ECOG performance status of 0 or 1
  • HER2-negative

Who cannot join

  • Prior treatment with CDK4/6 inhibitor
  • Locally advanced (unresectable) or inflammatory breast cancer
  • Non-breast cancer malignancy other than basal/squamous cell skin cancer or carcinoma in situ of cervix
  • Prior adjuvant therapy for breast cancer
  • Systemic anticancer therapy other than ribociclib or letrozole

Trial locations and contacts

1 site in 1 country.

United States1 site
  • Brigham and Women's Hospital

    Boston, Massachusetts, 02120

Other trials in United States

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 initiative1-4 EmulatioN of Comparative Oncology trials with Real-world Evidence (ENCORE) 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 MONALEESA-2 trial. MONALEESA-2 was a Phase III, double-blind, randomized study assessing the efficacy and safety of ribociclib (600 mg orally once daily on days 1-21 of a 28-day cycle, followed by 7 days off) in combination with letrozole (2.5 mg orally once daily, continuously) versus letrozole alone in postmenopausal women with hormone receptor-positive [estrogen receptor (ER) and/or progesterone receptor (PR)], human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer who had not received prior systemic treatment for their advanced disease.

Being tested
Initiation of ribociclib, Initiation of letrozole

What participants receive

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

  • Initiation of ribociclibDrug

    Initiation of ribociclib 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 groups in NCT07274709
Study groupRoleWhat they receive
Initiation of ribociclib plus letrozoleExposure group
Receives: Drug: Initiation of ribociclib
Initiation of letrozoleReference group
Receives: Drug: Initiation of ribociclib; Drug: Initiation of letrozole

What is being measured

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

  1. Time to all-cause mortality/overall survival (OS)

    Hazard ratio (95% CI)

    Measured: From time of initiation of therapy through the earliest of death from any cause (the primary outcome of interest) or end of data availability (depending on specialty oncology registry data provider, end of data ranges from June 2023 to April 2024)

Timeline

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

  1. First posted10 Dec 2025
  2. Study start7 Sep 2025
  3. Primary completion1 Jan 2026
  4. Study completion1 Jan 2026

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
2,495 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07274709
Sponsor's protocol ID
2022P002556-ENC-MONALEESA-2
Other IDs
75F40122C00181
Status last verified
Nov 2025
First submitted
20 Nov 2025
Last updated
12 May 2026
Results posted
No
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

An observational study of Advanced Breast Cancer, run by Shirley Vichy Wang 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 6 inclusion and 5 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 (OS) (time frame: From time of initiation of therapy through the earliest of death from any cause (the primary outcome of interest) or end of data availability (depending on specialty oncology registry data provider, end of data ranges from June 2023 to 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.

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