Real-world Studies of CDK4/6 Inhibitors

A Real-world Study on the Treatment of HR+/HER2- Advanced Breast Cancer Patients With CDK4/6 Inhibitors and Treatment Options After Drug Resistance.

A single-center, real-world study evaluated the clinical outcomes and safety of CDK4/6 inhibitors combined with endocrine therapy in HR+/HER2- advanced breast cancer, and conducted a summary analysis of the clinical treatment options after the progression of CDK4/6 inhibitors.

Study Overview

• Status: Recruiting
• Conditions: Breast Cancer

Detailed Description

This study aims to collect clinical data and case information from real-world clinical practice of patients with HR+/HER2- advanced breast cancer treated with CDK4/6 inhibitors combined with endocrine therapy.

The main research objectives include: 1. To evaluate the differences in efficacy among different CDK4/6 inhibitors combination regimens in advanced patients; 2. To investigate the subsequent treatment options chosen by patients in the real world after progression on CDK4/6 inhibitors, with the aim of constructing a predictive model for the response to subsequent treatments, thereby providing support for clinical decision-making for both doctors and patients in such situations.

The secondary objectives include: 1. To truly reflect the differences in adverse reactions of different CDK4/6 inhibitors in the Chinese population through the collection of laboratory and imaging results; 2. To collect tumor samples or peripheral blood samples from some patients for genomic and transcriptomic analyses, in preparation for translational research on the mechanism of CDK4/6 inhibitors resistance.

• Study Type: Observational
• Enrollment (Estimated): 245

Contacts and Locations

• Study Contact: Name: Yehui Shi, MD; Phone Number: 022-23340123-3252; Email: shiyehui@tjmuch.com
• Study Contact Backup: Name: Yiran Si, MD; Phone Number: 022-23340123-3252

Study Locations

• China
  • Tianjin, China, 300060
    • Recruiting
    • Tianjin Medical University Cancer Insititute and Hospital
    • Contact: Yehui Shi, MD; Phone Number: 022-23340124-3252; Email: shiyehui@tjmuch.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients who were diagnosed as HR+/HER2- (as defined by the ASCO/CAP guidelines) advanced breast cancer between March 2022 to March 2025

Description

Inclusion Criteria:

1. Age ≥ 18 years old;
2. Patients diagnosed with HR+/HER2- (as defined by the ASCO/CAP guidelines) advanced breast cancer who were treated in our hospital from March 2022 to March 2025;
3. Received CDK4/6 inhibitors (including but not limited to the four currently marketed ones: palbociclib, abemaciclib, ribociclib, and dalpiciclib) as advanced-stage treatment for at least one cycle;
4. Have complete medical history records, including demographic information, pathological reports, treatment records, laboratory test results, and imaging examination reports, etc.

Exclusion Criteria:

1. Incomplete medical history data.
2. Only received CDK4/6 inhibitors monotherapy.
3. Received CDK4/6 inhibitors as neoadjuvant/postoperative adjuvant intensification therapy.

Study Plan

How is the study designed?

Number of groups / cohorts

5

Cohorts and Interventions

Group / Cohort
Palbociclib cohort; Use palbociclib in combination with endocrine therapy as the treatment regimen.
Abemaciclib cohort; Use abemaciclib in combination with endocrine therapy as the treatment regimen.
Ribociclib cohort; Use ribociclib in combination with endocrine therapy as the treatment regimen.
Dalcetrapib cohort; Use dalcetrapib in combination with endocrine therapy as the treatment regimen.
Other CDK4/6 inhibitors cohort; Use other CDK4/6 inhibitors in combination with endocrine therapy (including participation in clinical trials of CDK4/6 inhibitors) as the treatment regimen.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
rwPFS1 and rwPFS2	Real-world progression-free survival (rwPFS1) during treatment with CDK4/6 inhibitors and real-world progression-free survival (rwPFS2) of subsequent treatment lines selected by clinicians after progression on CDK4/6 inhibitor therapy.	6 weeks

Collaborators and Investigators

• Sponsor: Tianjin Medical University Cancer Institute and Hospital

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2025
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): June 1, 2027

Study Registration Dates

• First Submitted: February 5, 2026
• First Submitted That Met QC Criteria: February 5, 2026
• First Posted (Actual): February 12, 2026

Study Record Updates

• Last Update Posted (Actual): February 12, 2026
• Last Update Submitted That Met QC Criteria: February 5, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Ribociclib; Dalcetrapib; Palbociclib; Abemaciclib; HR+/HER2- breast cancer; CDK4/6 inhibitors; CDK4/6 inhibitors resistance
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms
• Other Study ID Numbers: TJMUCIH-BC-CDK4/6i-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: At the stage of result publication, we will provide the IPD data in accordance with the specific requirements from the ICMJE journal.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No