An Exploratory Study on Predicting the Efficacy of Dalpiciclib in Combination With Endocrine Therapy for HR-Positive and HER2-Negative Recurrent/Metastatic Breast Cancer Patients After CDK4/6 Inhibitor Treatment Failure Using 18F-FES PET/CT
CDK4/6 inhibitors are currently the standard treatment for female breast cancer patients with HR+ tumors. However, there is no established standard treatment for patients who experience treatment failure with CDK4/6 inhibitors. The MAINTAIN study has shown clinical benefits by switching to Ribociclib and changing endocrine therapy after progression on CDK4/6 inhibitors. We hypothesize that combining Dalpiciclib with physician-selected endocrine therapy, following treatment failure with CDK4/6 inhibitors, would similarly lead to improved patient survival. In this study, 18F-FES PET/CT will be employed as a non-invasive alternative to biopsy techniques for evaluating the expression of ER in various systemic lesions of the patients.
• The recent pathology results showed HR-positive and HER2-negative.
• 18F-FES-PET/CT showed at least one ER-positive lesion.
• Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) score: 0-2 points.
• Expected survival time ≥ 3 months.
• Previous antitumor therapy: (1) (neo)adjuvant treatment with Palbociclib or Abemaciclib or Ribociclib or relapse after adjuvant treatment with Palbociclib or Abemaciclib or Ribociclib; (2) receiving Palbociclib or Abemaciclib or Ribociclib-based treatment in the context of metastatic breast cancer or disease progression after treatment; (3) previously received ≤1 line of chemotherapy for recurrent or metastatic breast cancer; (4) previously received ≤3 lines of endocrine therapy for recurrent or metastatic breast cancer.
• Willing to undergo 18F-FDG PET/CT standard imaging.
• At least one measurable lesion outside the skull according to RECIST V1.1.
• The function of important organs meets the requirements.
• The subjects have recovered from any adverse event related to previous tumor treatment (≤ Grade 1) before the first administration of the investigational drug.