A Phase 2 interventional study of Dalpiciclib 125mg and Aromatase Inhibitor in Breast Cancer and HR Positive/HER2 Low Breast Cancer, sponsored by Tang-Du Hospital. Not yet recruiting. Open to female participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-06-11.
Sponsored by Tang-Du Hospital · Phase 2, Interventional, and Treatment
This is a phase II, single-arm, prospective exploratory study to evaluate the efficacy and safety of neoadjuvant dalpiciclib (a CDK4/6 inhibitor) plus an aromatase inhibitor (AI) followed by SHR-A1811 (an anti-HER2 antibody-drug conjugate) in patients with intermediate-to-high risk, hormone receptor-positive (HR+), HER2-low breast cancer. Patients will receive dalpiciclib (125 mg orally once daily, days 1-21, every 4 weeks) plus AI (anastrozole 1 mg, letrozole 2.5 mg, or exemestane 25 mg once daily) for 4 cycles, followed by SHR-A1811 (4.8 mg/kg intravenously every 3 weeks) for 4 cycles. The primary endpoint is objective response rate (ORR) per RECIST 1.1. Secondary endpoints include pathological complete response (pCR), breast-conserving surgery rate, event-free survival (EFS), change in Ki-67 index, and safety. A total of 20 participants will be enrolled.
This is a single-arm, open-label, phase II exploratory trial conducted at a single center (Second Affiliated Hospital of Air Force Medical University, China). The study aims to investigate the activity and safety of dalpiciclib plus an aromatase inhibitor (AI) followed by the HER2-directed antibody-drug conjugate (ADC) SHR-A1811 as neoadjuvant therapy for patients with intermediate-to-high risk, hormone receptor-positive (HR+), HER2-low breast cancer.
Preclinical evidence suggests that CDK4/6 inhibition may enhance the immunogenic cell death induced by ADCs and overcome tumor heterogeneity. Dalpiciclib is a selective CDK4/6 inhibitor with a distinct piperidine structure associated with low hepatotoxicity and minimal gastrointestinal side effects. SHR-A1811 is a HER2-targeted ADC composed of a humanized anti-HER2 IgG1 monoclonal antibody (based on trastuzumab sequence), a cleavable maleimide tetrapeptide (GGFG) linker, and a DNA topoisomerase I inhibitor (SHR169265). It demonstrates bystander killing of HER2-low cells. The 4-cycle induction with dalpiciclib plus AI prior to SHR-A1811 is designed to reduce tumor proliferation and potentially prime the tumor microenvironment before ADC administration.
Treatment administration
12,547 studies on the registry are indexed under Breast Neoplasms; 2,892 are open to participants now.
This study's planned enrollment of 20 is below the median of 72 across 9,305 interventional studies indexed under Breast Neoplasms.
Browse Breast Neoplasms studies →Tang-Du Hospital is the lead sponsor of 164 studies on the registry; 77 are open to participants now.
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At least one of the following intermediate-to-high risk factors:
Exclusion Criteria:
Drug: Dalpiciclib 125mg · Drug: Aromatase Inhibitor · Drug: SHR-A1811
CDK4/6 inhibitor, 125 mg oral tablet, taken once daily on days 1-21 of each 28 day cycle for 4 cycles.
Includes anastrozole 1 mg/day, letrozole 2.5 mg/day, or exemestane 25 mg/day, administered orally once daily for 4 cycles.
Anti-HER2 antibody-drug conjugate (ADC), 4.8 mg/kg intravenous infusion once every 3 weeks for 4 cycles
Objective Response Rate (ORR)
Proportion of patients achieving complete response (CR) or partial response (PR) per RECIST 1.1
Time frame: After completion of 8 cycles of neoadjuvant therapy (Cycles 1-4: 28 days/cycle; Cycles 5-8: 21 days/cycle), within 4 weeks prior to surgery
Pathological Complete Response Rate (pCR): ypT0-is/ypN0
pCR is defined as absence of invasive carcinoma in the breast primary tumor (ypT0/is) and absence of tumor cells in axillary lymph nodes (ypN0) on pathological examination of the surgical specimen after neoadjuvant therapy. Presence of ductal carcinoma in situ (DCIS) alone is allowed.
Time frame: At the time of surgery, performed within 4 weeks after completion of 8 cycles of neoadjuvant therapy (Cycles 1-4: 28 days/cycle; Cycles 5-8: 21 days/cycle).
Breast-Conserving Surgery Rate
Proportion of participants who undergo breast-conserving surgery (BCS) after neoadjuvant therapy. BCS is defined as surgical resection of the primary tumor with negative margins while preserving the breast contour, as opposed to total mastectomy.
Time frame: At the time of surgery
Event-Free Survival (EFS)
EFS is defined as the time from enrollment to the first occurrence of any of the following events: disease progression (local, regional, or distant) during neoadjuvant therapy, disease recurrence after surgery (local, regional, or distant), contralateral breast cancer, any secondary malignancy, or death from any cause. Participants without an event at the time of last follow-up are censored.
Time frame: From enrollment up to 5 years after last patient enrollment (assessed every 3 months during the first year, then every 6 months thereafter
Ki-67 Index Change
Ki-67 index is measured by immunohistochemistry (IHC) as the percentage of tumor cells with positive nuclear staining. The scale is the Ki-67 proliferation index, which ranges from 0% (minimum) to 100% (maximum). Higher scores indicate a worse outcome (higher proliferative activity). The change is calculated as Ki-67 index at surgery minus Ki-67 index at baseline. A negative value (reduction) indicates a better outcome (decreased proliferation), while a positive value (increase) indicates a worse outcome.
Time frame: Baseline (pre-treatment core needle biopsy) and at surgery (post-neoadjuvant surgical specimen).
Incidence of Adverse Events (AEs) and Serious Adverse Events (SAEs)
Safety outcomes include: incidence of any AE, incidence of grade ≥3 AE (per NCI-CTCAE version 6.0), incidence of SAEs, incidence of AE leading to treatment discontinuation or dose modification, and incidence of AE by system organ class and preferred term. Laboratory abnormalities, vital signs, ECG parameters (QTcF, heart rate), and left ventricular ejection fraction (LVEF) are also summarized.
Time frame: From signing of informed consent through 30 days after the last dose of study drug, or until initiation of new anticancer therapy, whichever occurs first.
No study locations are listed for this record.
Plan to share: No — The informed consent form signed by participants does not include provisions for sharing individual participant data with external researchers.
No publications or documents are linked to this record.
This study is not yet recruiting, as verified in Jun 2026. You cannot join it, but the record below documents what was studied.
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Tang-Du Hospital