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Completed

NCT Number: NCT07647042

A Real-World Study of Early Breast Cancer Patients Eligible for Treatment With CDK4/6 Inhibitors

The aim of this study was to describe treatment patterns, patient characteristics and clinical outcomes among hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2-) early breast cancer (eBC) patients who became eligible for treatment with cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) in the real-world setting after the FDA approval of ribociclib treatment for eBC.

The study used data abstracted from structured and unstructured patient electronic health records from sites available in the Integra Connect PrecisionQ database (secondary data use).

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Key information

Conditions

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

Age range

18 year–100 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Novartis

East Hanover, New Jersey, 07936, United States

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Diagnosed with HR+/HER2- breast cancer.
  • No evidence of distant metastatic spread.
  • Underwent primary breast cancer surgery (mastectomy/lumpectomy) during the study period.
  • Initiated adjuvant ET within 12 months of surgery date and after September 17, 2024, to the period up to 3 months prior to the data cutoff date.
  • Had at least one visit during the baseline period and at least one visit one day after the index date.
  • Patients included must have met one of the following conditions at the time of diagnosis or surgery:
  • Nodal stage (N) N2 or N3 disease.
  • N1 any anatomic tumor size (T), including micrometastatic patients except T0 N1mi and T1 N1mi; For T0 N1mi and T1 N1mi patients with Grade 3 disease alone will be selected.
  • Node-negative with the following high-risk criteria:
  • Tumor size is T3, T4
  • Tumor size is T2 and Grade 3
  • Tumor size is T2 with Grade 2 and either Ki-67 score ≥ 20% or genomic high risk based on Oncotype Dx/Mammaprint/Endopredict/Prosigna

Exclusion criteria

  • Use of any prior CDK4/6i before the index date.
  • Missing T or N values for both clinical and surgical stage.
  • Diagnosis of cancer other than breast cancer.
  • Evidence of participation in a clinical trial at any time during the study observation period.

Treatment and study plan

Primary outcomes

  1. Percentage of Eligible Population that Received Genetic Testing

    Time frame: Baseline, up to approximately 1 year, 7 months

    Testing includes germline mutation testing, Oncotype DX testing, Ki-67 scoring, and other breast cancer specific genetic tests (breast cancer index, Mammaprint, Endopredict, Prosigna).

  2. Number and Percentage of Patients by Treatment Regimen

    Time frame: Baseline, up to approximately 1 year, 7 months

    Number and percentage of patients by treatment regimen in the neo-adjuvant and adjuvant setting, stratified by patient and provider characteristics, and CDK4/6i eligibility.

  3. Number and Percentage of Patients With Treatment Switches

    Time frame: Baseline, up to approximately 1 year, 7 months

    Number and percentage of patients with treatment switches within the CDK4/6i and aromatase inhibitor (AI) drug classes, classified as switch due to toxicity vs. other reason.

  4. Time From Surgery to Start of Adjuvant ET

    Time frame: Up to 1 year

  5. Time From Surgery to Start of CDK4/6i Treatment

    Time frame: Up to 1 year

  6. Time From ET to Start of CDK4/6i Treatment

    Time frame: Up to approximately 1 year, 7 months

  7. Time From Adjuvant Chemotherapy to Start of CDK4/6i Treatment

    Time frame: Up to approximately 1 year, 4 months

    Time from initial adjuvant Chemotherapy to the start of CDK4/6i treatment, stratified by presence of adverse events prior to CDK4/6i initiation.

Secondary outcomes

  1. Baseline Demographics

    Time frame: Baseline

  2. Height

    Time frame: Baseline

  3. Weight

    Time frame: Baseline

  4. Body Mass Index (BMI)

    Time frame: Baseline

  5. Number and Percentage of Patients by Patient Characteristics

    Time frame: Baseline

    Patient characteristics include:

    • Menopausal status
    • Geographic location
    • Payer type
    • Index year
    • Vital status

  6. Age at Initial Diagnosis of BC

    Time frame: Baseline

  7. Duration Between Diagnosis of BC and Initiation of Adjuvant ET

    Time frame: Baseline

  8. Number and Percentage of Patients by Clinical Characteristics

    Time frame: Baseline

    Clinical characteristics include:

    • Eastern Cooperative Oncology Group (ECOG) performance status grade
    • Tumor, Node, Metastasis (T.N.M) classification at BC diagnosis and after surgery
    • Anatomical staging at BC diagnosis
    • Tumor grade at BC diagnosis
    • HR+ and HER2- status
    • QT prolongation
    • Molecular subtype
    • Mutation status
    • Genomic scoring tests (where available)
    • Comorbidities
    • Adverse events

  9. Red Blood Cell Count

    Time frame: Basline

  10. Hemoglobin Level

    Time frame: Baseline

  11. Hematocrit Level

    Time frame: Baseline

  12. White Blood Cell Count

    Time frame: Baseline

  13. Platelet Count

    Time frame: Baseline

  14. Absolute Neutrophil Count (ANC)

    Time frame: Baseline

  15. Serum Creatinine Level

    Time frame: Baseline

  16. Liver Enzyme Levels

    Time frame: Baseline

    • Aspartate aminotransferase (AST)
    • Alanine aminotransferase (ALT)
    • Alkaline phosphatase (ALP)

  17. Bilirubin Level

    Time frame: Baseline

  18. Number and Percentage of Patients by Medications Used and Procedures

    Time frame: Baseline, up to approximately 1 year, 7 months

  19. Time to Discontinuation or Death

    Time frame: Up to approximately 1 year, 7 months

    Time to all-cause discontinuation or death (TTD-all cause), TTD-all cause but recurrence, and time to adverse event-related discontinuation or death (TTD from AE).

  20. Persistence of CDK4/6i Use

    Time frame: Up to approximately 1 year, 7 months

    Persistence is defined as the number of days patients were taking a CDK4/6i during a pre-defined time-interval.

  21. Number and Percentage of Patients who Discontinued Adjuvant Treatment

    Time frame: Up to approximately 1 year, 7 months

  22. Number of Patients by Reason for CDK4/6i Treatment Discontinuation

    Time frame: Up to approximately 1 year, 7 months

  23. Duration of Treatment

    Time frame: Up to approximately 1 year, 7 months

  24. Percentage of Patients by Dose of Treatment

    Time frame: Up to approximately 1 year, 7 months

  25. Cumulative Dose

    Time frame: Up to approximately 1 year, 7 months

    Cumulative dose is defined as the sum of individual doses during the initial adjuvant regimen.

  26. Dose Intensity

    Time frame: Up to approximately 1 year, 7 months

    Dose intensity is defined as the cumulative dose / total time period of treatment.

  27. Relative Dose Intensity (RDI)

    Time frame: Up to approximately 1 year, 7 months

    RDI is defined as the observed dose intensity / expected dose intensity x 100.

  28. Number and Percentage of Patients With Dose Reductions During Follow-up

    Time frame: Up to approximately 1 year, 7 months

  29. Time to First and Subsequent Dose Reductions of CDK4/6is

    Time frame: Up to approximately 1 year, 7 months

  30. Number and Percentage of Patients With Drug Interruptions

    Time frame: Up to approximately 1 year, 7 months

Sponsors and collaborators

Lead sponsor

Novartis Pharmaceuticals

Industry

Registry information

Official study title

Longitudinal Evaluation of Early Breast Cancer With Adjuvant Real-World Data in the Post-CDK4/6 Inhibitor Approval Era: Analysis Using Integra PrecisionQ Oncology Database (LEEWARD)

Acronym: LEEWARD

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jun 15, 2026
Registry last updated
Jun 15, 2026

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.

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