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Study identifier: NCT06377852 Synced from ClinicalTrials.gov · July 28, 2026
● Recruiting

The CDK4/6 Inhibitor Dosing Knowledge (CDK) Study

Condition: Metastatic Breast Cancer  ·  Sponsor: American Society of Clinical Oncology

PhasePhase 3
Planned participants500
Who can joinAll sexes, 65 Years to no upper limit
Healthy volunteersNo

About this study

The purpose of this study is to generate evidence on an alternative dosing strategy for CDK4/6 inhibitors to help more patients with Metastatic Breast Cancer (MBC) (age ≥ 65 years) tolerate side effects and stay on treatment longer, to derive the most clinical benefit from these drugs. The primary objective of the CDK Study is to compare time to treatment discontinuation (TTD) on the approved dosing for palbociclib (125 mg orally daily on days 1-21 of 28-day cycle) or ribociclib (600 mg orally daily on days 1-21 of 28-day cycle) vs. TTD using titrated dosing approach with the same schedule but starting at a lower dose of palbociclib (100 mg or 75 mg) or ribociclib (400 mg or 200 mg) and escalating the dose if well-tolerated in combination with provider/patient choice endocrine therapy (aromatase inhibitor (AI) or fulvestrant) in patients age 65 or older with HR+/HER2- MBC. The secondary and exploratory objectives will generate evidence needed to personalize treatment decisions by comparing patient-centric secondary outcomes and evaluating baseline factors. Together with their treating physician, participants will choose the CDK4/6 inhibitor (palbociclib or ribociclib) and which endocrine therapy (aromatase inhibitor or fulvestrant) of their choice but will be randomized to either Arm 1 (indicated dosing) or Arm 2 (titrated dosing). Note: Telehealth visits are allowed at any time per institutional guidelines. In addition, the study allows for remote consenting per instituti…

This description comes directly from the study's public registry record.

Talk to the study team

Jackie Perez, MPH  ·  571-483-1300  ·  CDKstudy@asco.org

Cindy MacInnis, MBA  ·  CDKstudy@asco.org

Always discuss trial participation with your own doctor first.

Locations (73)

Ironwood Cancer & Research CentersChandler, Arizona, United StatesRecruiting
Ironwood Cancer & Research CentersGilbert, Arizona, United StatesRecruiting
Ironwood Cancer & Research CentersGlendale, Arizona, United StatesRecruiting
Ironwood Cancer & Research CentersGoodyear, Arizona, United StatesRecruiting
Ironwood Cancer & Research CentersMesa, Arizona, United StatesRecruiting
Ironwood Cancer & Research CentersMesa, Arizona, United StatesRecruiting
Ironwood Cancer & Research CentersPhoenix, Arizona, United StatesRecruiting
Ironwood Cancer & Research CentersScottsdale, Arizona, United StatesRecruiting
University of Colorado Anschutz Medical CampusAurora, Colorado, United StatesRecruiting
UCHealth Cherry Creek Medical CenterDenver, Colorado, United StatesRecruiting
UCHealth Highlands Ranch HospitalHighlands Ranch, Colorado, United StatesRecruiting
Smilow Cancer Hospital Care Center - DerbyDerby, Connecticut, United StatesRecruiting

+ 61 more locations — full list on the registry record.

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Source record: clinicaltrials.gov/study/NCT06377852