Study to Compare Overall Survival in Medicare Patients With Metastatic Breast Cancer Treated With a Medicine Called Palbociclib in Combination With Aromatase Inhibitor and Aromatase Inhibitor by Itself.

A retrospective study of de-identified (to preserve patient privacy) patient information from the SEER-Medicare Database to compare overall survival of first line palbociclib + aromatase inhibitor (AI) therapy versus AI therapy alone treatment in women or men aged 65 and older with newly diagnosed hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) metastatic breast cancer (MBC) in the United States

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Key information

Conditions

Breast Cancer Breast Diseases Breast Neoplasms Neoplasm Metastasis Neoplasms Neoplasms by Site Neoplastic Processes Pathologic Processes Pathological Conditions, Signs and Symptoms Skin Diseases Skin and Connective Tissue Diseases

Age range

65 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Pfizer New York

New York, 10001, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

De novo metastatic (stage IV) disease at initial breast cancer diagnosis during 2015-2019
HR+/HER2- molecular subtype at diagnosis
Initiated 1L systemic therapy with palbociclib + AI or AI alone

Exclusion criteria

Patients will be excluded if their metastatic breast cancer diagnosis was first recorded in a death certificate or at the time of autopsy.

Treatment and study plan

Palbociclib

Drug

Palbociclib with an aromatase inhibitor therapy

Other names: Ibrance

Aromatase Inhibitor

Drug

Aromatase Inhibitor Therapy

Other names: letrozole, anastrozole, exemestane

Primary outcomes

Overall Survival According to Unadjusted Analysis

Time frame: From index date to death (approximately 69.9 months); retrospective data evaluated in 4 months (approximately) of this study

Overall survival was defined as time in months from the study index date to all cause death. Study index date in this outcome measure was the date of first line of treatment initiation with palbociclib + AI or AI alone after the de novo mBC diagnosis. De novo mBC referred to breast cancer that physician diagnosed for the first time after it had already spread outside of the breast to distant parts of the body. Unadjusted analysis: analysis not considering any covariates, specifically potential differences in baseline characteristics that could confound the association between treatment and survival. Overall survival was assessed using Kaplan-Meier analysis.
Overall Survival According to Stabilized Inverse Probability of Treatment Weighted (sIPTW) Analysis

Time frame: From index date to death (approximately 69.9 months); retrospective data evaluated in 4 months (approximately) of this study

Overall survival was defined as time in months from the study index date to all cause death. Study index date in this outcome measure was the date of first line of treatment initiation with palbociclib + AI or AI alone after the de novo mBC diagnosis. De novo mBC referred to breast cancer that physician diagnosed for the first time after it had already spread outside of the breast to distant parts of the body. sIPTW analysis: stabilized inverse probability treatment weighting. This is a statistical method that reweights participants to create groups with similar baseline characteristics. The analysis therefore adjusts for differences in baseline characteristics that could confound the association between treatment and survival. Overall survival was assessed using Kaplan-Meier analysis.

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Registry information

Official study title

Comparative Assessment of Overall Survival in Medicare Patients With HR+/HER2- Metastatic Breast Cancer Treated With Palbociclib in Combination With Aromatase Inhibitor (AI vs. AI Alone)

Important dates

Study start: 2023
Primary completion: 2024
Study completion: 2024
First posted: Oct 17, 2023
Registry last updated: Nov 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

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