Efficacy and Safety of CDK4/6 Inhibitors Combined With Endocrine Therapy in HR+/HER2- Neoadjuvant Therapy for Early Breast Cancer

Single-arm Exploratory Study of Efficacy and Safety of CDK4/6 Inhibitors Combined With Endocrine Therapy in HR+/HER2- Neoadjuvant Therapy for Early Breast Cancer

This is a single arm, open label, phase 2 trial aimed to investigate the effects and safety of neoadjuvant CDK4/6 inhibitors in combination with endocrine for HR+/HER2- breast cancer. A total of 40 patients with stage II-III HR+/HER2- breast cancer will be enrolled. Six 4-week cycles of adjuvant therapy will be administrated.Premenopausal or perimenopausal patients should combine ovarian function suppression, including bilateral oophorectomy or treatment with gonadotropin-releasing hormone agonists.

Study Overview

• Status: Active, not recruiting
• Conditions: HR+/HER2- Breast Cancer
• Intervention / Treatment: Drug: CDK4/6 inhibitors+Endocrine Therapy

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Phase 2

Contacts and Locations

Study Locations

• China
  • Hubei
    • Wuhan, Hubei, China
      • No. 119 Zhuodaoquan South Road

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• 1. Age ≥18 years old.

  2. Premenopausal and postmenopausal women or men with stage II-III disease (multifocal and/or multifocal early invasive breast cancer) if all tumors on histopathological examination meet the pathological criteria for ER and/or PR > 10% and HER2- (HER2 expression of 0 or 1+ or 2+ and negative FISH test).

  3.Patients had to have histologically confirmed ER and (or PR>10%, HER2 -, early-stage invasive disease.

  4.Intolerance or insensitivity to neoadjuvant chemotherapy: 2 cycles of neoadjuvant chemotherapy, PD/SD according to tumor evaluation, old age, and basic diseases can not tolerate chemotherapy.

  5. ECOG PS score 0-2.

  6. Patients must be able and willing to swallow and retain oral medications.

  7. In premenopausal women, a serum or urine pregnancy test had to be negative within 14 days of enrollment or in women who had been amenorrhea for less than 12 months at enrollment.

  8.Patients who had received neoadjuvant endocrine therapy were eligible if they were enrolled within 6 months of the initial histologic diagnosis and had completed no more than 2 months of neoadjuvant endocrine therapy.

  9. Absolute neutrophil count ≥1500/µL, platelet ≥100000/mm3, hemoglobin ≥10g/dL

Exclusion Criteria:

• 1. Prior treatment with any CDK4/6 inhibitor.

  2. Inflammatory or stage IV or bilateral breast cancer.

  3. History of allergic reactions caused by chemical or biological components similar to CDK4/6 inhibitors.

Patients who received any drugs or substances that were effective CYP3A isoenzyme inhibitors or inducers within 7 days of enrollment.

5. Uncontrolled coexisting medical conditions may limit adherence to study requirements.

6. Pregnant women with a negative pregnancy test within 14 days before admission or women of childbearing potential.

7. Patients with a history of any malignancy were not eligible.

8. Patients receiving endocrine therapy within 5 years before diagnosis of current malignancy.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: treatment; CDK4/6 inhibitors+Endocrine Therapy every 28 days for 6 cycles	Drug: CDK4/6 inhibitors+Endocrine Therapy; CDK4/6 inhibitors：dalpiciclib,palbociclib,abemaciclib,ribociclib

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Objective Response Rate (ORR)	ORR is defined as proportion of patients demonstrating either a partial response (PR) or a complete response (CR)	up to 24 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
change in Ki67	change in Ki67 from baseline to end of treatment	up to 24 weeks
complete cell cycle arrest	The proportion of patients with Ki-67≤2.7% on day 15 of cycle 1 treatment	up to 4 weeks
Invasive disease free survival（iDFS）	Time from adjuvant therapy to disease recurrence in patients with invasive disease	up to 3 years

Collaborators and Investigators

• Sponsor: Xinhong Wu, PhD

Study record dates

Study Major Dates

• Study Start (Actual): December 20, 2024
• Primary Completion (Estimated): December 20, 2026
• Study Completion (Estimated): June 20, 2027

Study Registration Dates

• First Submitted: August 12, 2025
• First Submitted That Met QC Criteria: August 12, 2025
• First Posted (Actual): August 19, 2025

Study Record Updates

• Last Update Posted (Actual): August 19, 2025
• Last Update Submitted That Met QC Criteria: August 12, 2025
• Last Verified: December 1, 2024

More Information

Terms related to this study

• Keywords: neoadjuvant; HR+/HER2- breast cancer; CDK4/6 inhibitors
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Breast Neoplasms
• Other Study ID Numbers: OBU-BC-II-209

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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