Real-World Outcomes of Patients With Metastatic Breast Cancer After Treatment With First-Line ET+CDK4/6i

NCT06975371 | Completed

• 1 other identifier: U31402-0012-NIS-MA
• Study Type: observational
• Target: 1,415
• Locations: 1 country
• Sites: 1

Brief Summary

This study aims to assess the treatment patterns and real-world outcomes of HR+/HER- metastatic breast cancer patients who have progressed on 1L ET + CDK4/6i and started a second line (2L) treatment within a real-world cohort in the United States Flatiron Health Database.

Conditions

Advanced/Metastatic HER2-negative Breast Cancer

Keywords

HR-positive; HER2-negative; Metastatic breast cancer

Outcome Measures

Primary Outcomes (1)

• Real-world progression-free survival (rwPFS)

  Real-world progression-free survival (rwPFS) will be calculated as the time from the index treatment date to the date of the first documented rwP event occurring \>14 days after the index treatment date or date of death, whichever occurs first.

  Baseline up to end of observation period, approximately 7 years 9 months

Secondary Outcomes (3)

• Real-world overall survival (rwOS)

  Baseline up to end of observation period, approximately 7 years 9 months

• Real-world time to discontinuation or death (rwTTD/D)

  Baseline up to end of observation period, approximately 7 years 9 months

• Real-world time to next treatment or death (rwTTNT/D)

  Baseline up to end of observation period, approximately 7 years 9 months

Study Arms (1)

HR+/HER2- metastatic breast cancer

Adults in the Flatiron database who are diagnosed with HR+/HER2- metastatic breast cancer and initiated a subsequent line of therapy (i.e., 2L) after progressing on 1L treatment with ET+CDK4/6i.

Other: No drug

Interventions

No drug OTHER

No study drug was administered in this non-interventional study.

HR+/HER2- metastatic breast cancer

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

The study cohort consists of adults in the Flatiron database who are diagnosed with HR+/HER2- mBC and initiated a subsequent LOT (i.e., 2L) after progressing on 1L treatment with ET+CDK4/6i.

You may qualify if:

• Patients with evidence of Stage IV or recurrent mBC with a metastatic diagnosis date on or after January 1, 2017
• Aged ≥18 years at mBC diagnosis date
• Received 1L ET + CDK 4/6i, with no other systemic agents, in the metastatic setting
• Had evidence of a rwP event during 1L ET + CDK 4/6i
• Evidence of a subsequent LOT following 1L ET + CDK 4/6i (start date of subsequent LOT = index treatment date)
• A record of HR+ status in the closest estrogen receptor (ER) or progesterone receptor (PR) test result occurring prior to or within 30 days after the index treatment date
• A record of HER2- status in the closest HER2 test result recorded prior to or on the index treatment date
• Index treatment date occurring at least 90 days prior to end of study period (30Sep2024)

You may not qualify if:

• A record of estrogen receptor 1 (ESR1), phosphatidylinositol4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), V-akt murine thymoma viral oncogene homolog (AKT1), phosphatase and tensin homolog (PTEN), or germline breast cancer gene (gBRCA) alteration/mutation prior to or within 30 days after index treatment date

Sponsors & Collaborators

• Daiichi Sankyo: lead

Study Sites (1)

Flatiron Health, Inc

New York, New York, 10013, United States

Location

MeSH Terms

Conditions

Breast Neoplasms

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Study Officials

• Director

  Daiichi Sankyo

  STUDY DIRECTOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 9, 2025
• First Posted: May 16, 2025
• Study Start: April 14, 2025
• Primary Completion: May 8, 2025
• Study Completion: August 5, 2025
• Last Updated: October 7, 2025

Record last verified: 2025-10

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)