Home > Breast Cancer Information > Facts & Statistics > Research Studies > Research Table Topics > CDK4/6 Inhibitors for Early Breast Cancer Treatment

Research table: CDK4/6 inhibitors for early breast cancer treatment

This summary table contains detailed information about research studies. Summary tables are a useful way to look at the science behind many breast cancer guidelines and recommendations. However, to get the most out of the tables, it’s important to understand some key concepts. Learn how to read a research table.

Introduction: CDK4/6 inhibitors are drugs that target enzymes called CDK4 and CDK6. These enzymes are important in cell division. CDK4/6 inhibitors are designed to interrupt the growth of cancer cells.

The CDK4/6 inhibitors abemaciclib (Verzenio) and ribociclib (Kisqali) are FDA-approved for the treatment of some hormone receptor-positive early breast cancers.

Hormone therapy plus abemaciclib or ribociclib may reduce the risk of breast cancer recurrence better than hormone therapy alone in people with some hormone receptor-positive, HER2-negative early breast cancers at high risk of recurrence (high risk of a return of breast cancer).

    Learn more about abemaciclib and ribociclib (including side effects) and early breast cancer treatment.

    Learn about CDK4/6 inhibitors and metastatic breast cancer treatment.

    Learn about the strengths and weaknesses of different types of studies.

    Study selection criteria: Randomized clinical trials with at least 1,000 participants with hormone receptor-positive, HER2-negative early breast cancer.

    Study

    Study Population
    (number of participants)

    Follow-up
    (years)

    Percent Surviving with No Breast Cancer Recurrence—
    Hormone Therapy plus CDK4/6 Inhibitor

    Percent Surviving with No Breast Cancer Recurrence-
    Hormone Therapy Alone
    (no CDK4/6 Inhibitor)

    Absolute Improvement in Survival with No Breast Cancer Recurrence with the Addition of CDK4/6 Inhibitor to Treatment with Hormone Therapy

    Randomized clinical trials – abemaciclib

    monarchE [1]

    5,637

    5

    84%

    76%

    8%

    Randomized clinical trials – ribociclib

    NATALEE [2]

    5,101

    3

    90%

    87%

    3%

    Randomized clinical trials – palbociclib

    PALLAS [3]

    5,761

    4

    84%

    85%

    NS

    PENELOPE-B [4]

    1,250

    3½

    24%

    25%

    NS

    NS = No statistically significant difference between the 2 treatment groups

    References

    1. Rastogi P, O’Shaughnessy J, Martin M, et al. Adjuvant abemaciclib plus endocrine therapy for hormone receptor-positive, human epidermal growth factor receptor 2-negative, high-risk early breast cancer: results from a preplanned monarchE overall survival interim analysis, including 5-year efficacy outcomes. J Clin Oncol. 42(9):987-993, 2024.
    2. Slamon D, Lipatov O, Nowecki Z, et al. Ribociclib plus endocrine therapy in early breast cancer. N Engl J Med. 390(12):1080-1091, 2024.
    3. Gnant M, Dueck AC, Frantal S, et al. for the PALLAS groups and investigators. Adjuvant palbociclib for early breast cancer: the PALLAS trial results (ABCSG-42/AFT-05/BIG-14-03). J Clin Oncol. 40(3):282-293, 2022.
    4. Loibl S, Marmé F, Martin M, et al. Palbociclib for residual high-risk invasive HR-positive and HER2-negative early breast cancer-the Penelope-B trial. J Clin Oncol. 39(14):1518-1530, 2021.

    Updated 10/02/24