Phase II Trial of ctDNA-Guided Dalpiciclib and Endocrine Therapy to Reduce Chemotherapy in Women With Early-Stage HR-Positive, HER2-Negative Breast Cancer

What this Trial Is About

Researchers are evaluating a ctDNA-guided strategy to reduce the use of chemotherapy in women with hormone receptor-positive, HER2-negative early-stage breast cancer who are at high risk of recurrence. This Phase II randomized trial aims to see if combining the CDK46 inhibitor Dalpiciclib with endocrine therapy can safely decrease chemotherapy while maintaining treatment benefits. The study focuses on measuring ctDNA clearance and 3-year event-free survival. Participants are divided into two groups one receives taxane-based chemotherapy before surgery, and the other receives Dalpiciclib plus an aromatase inhibitor for four cycles before surgery. After surgery, treatment is adjusted based on ctDNA test results, with options including continued Dalpiciclib and endocrine therapy or additional chemotherapy. Premenopausal women in the experimental group also receive ovarian suppression. Treatments are given in cycles, with follow-up therapies lasting up to two years. Throughout the study, participants undergo ctDNA testing at baseline and before surgery using personalized tumor-informed panels. Regular tumor imaging and pathological evaluations are conducted to assess tumor response. Safety is closely monitored through lab tests, ECGs, and adverse event tracking. Clinic visits occur every 4 weeks during treatment and every 3 months during post-treatment follow-up, continuing up to three years to assess recurrence, progression, or survival.

ctDNA-Guided De-Escalation of Adjuvant Chemotherapy With Dalpiciclib in HR-Positive/HER2-Negative Breast Cancer