The CDK4/6 Inhibitor Dosing Knowledge (CDK) Study

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

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 ≥ 60 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 60 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 institutional guidelines.

About this trial record page

What this page shows

Public field values for ClinicalTrials.gov record NCT06377852, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.

What this page does not do

No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.

Where the data comes from

Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.

Last refresh

Last update posted Oct 6, 2026 · Synced Oct 16, 2026

Related: full search, browse by condition, browse by drug or therapy, browse by sponsor, browse by U.S. city.