Elderly patients with advanced triple-positive breast cancer have the characteristics of low physical status and poor treatment tolerance. Therefore, such patients are often unable to tolerate more toxic chemotherapy regimen, and it is particularly important to choose a highly effective and low-toxic treatment regimen. However, few studies have paid attention to the treatment of such patients in the past.

Pyrrotinib is a small molecule, irreversible, panerbb receptor tyrosine kinase inhibitor, which was independently developed by our country and has shown excellent efficacy in second-line anti-HER2 treatment of breast cancer, and has become the second-line standard treatment choice for advanced HER2-positive breast cancer. In addition, PHILA study results showed that the mPFS of pyrrotinib group reached 24 months. Compared with the control group, the duration of 10 months was significantly extended, indicating the significant efficacy of pyrrotinib in the first-line treatment of advanced HER2-positive breast cancer.

Darsili is a CDK4/6 inhibitor independently developed in China, which has been reconstructed and optimized in molecular structure, and has become a new CDK4/6 inhibitor with more powerful modification by introducing piperidine structure through replacement of classical electronic and other panbody. The results of DAWNA-2 study indicated that the mPFS of Dalsily combined AI group reached 30.6 months, which was significantly longer than 18.2 months of the control group, and was the longest in similar studies.

MUKDEN01 study, for the first time, tried the efficacy of pyrrotinib + letrozole + Dalsily regimen in the new adjuvant therapy of TPBC patients, and the results showed that ORR reached 87.4%, CR rate was 30.4%, and pCR rate was 35.4%. Therefore, to further confirm the efficacy and safety of this protocol in elderly patients with advanced triple positive breast cancer, we intend to conduct this study. This is a prospective, single-arm, single-center clinical trial in which participants were treated with darcilide +AI (letrozole/anastrozole/exemestane) + pyrrotinib until disease progression, toxicity became intolerable, informed consent was withdrawn, or investigator judgment required discontinuation. The successful development of this study provides a new direction for the first-line treatment of elderly advanced triple-positive breast cancer.

In this open design, single-arm, single-center, prospective clinical study, 28 elderly patients with triple-positive advanced breast cancer were planned to receive treatment with darcilil combined with pyrrotinib and AI until the disease progressed, toxicity became intolerable, informed consent was withdrawn, or the investigator judged that the drug must be discontinued. The main objective of this study was to observe the safety and efficacy of Dalcilil combined with pyrrotinib and AI in the treatment of triple-positive senile advanced breast cancer.

In this study, the screening period did not exceed 28 days, and qualified subjects entered the study treatment period (every 28 days is a treatment cycle) after completing the screening examination and evaluation, and conducted the study treatment and visit according to the protocol. Imaging evaluation was performed according to the clinical routine during the study treatment. The imaging evaluation could be carried out according to the RECIST 1.1 standard, and the evaluation result of the investigator was the final result. At the end of treatment/withdrawal from the study, subjects should visit the research center to complete the corresponding safety check and imaging evaluation; In addition, a visit to the research center was conducted 28 days after the last treatment to complete the corresponding safety assessment.

Safety follow-up: the subjects were followed up until the initiation of other antineoplastic drugs. All AE recovered to grade 0-1 or baseline levels or died, whichever was achieved first.

Efficacy follow-up: All subjects were required to be followed until tumor progression or death or withdrawal of informed consent, whichever came first.

Follow-up for survival: All subjects were followed for survival until death or withdrawal of informed consent or the end of the trial, whichever came first.

Inclusion Criteria:

• 1.Age: ≥65 years old; 2. Histologically confirmed stage IV TPBC; 3. Without prior treatment, adjuvant endocrine therapy and anti-HER2 therapy should be completed for more than one year; 4.TPBC is defined as HER2-positive (3+ by immunohistochemistry, or 2+ by fluorescence in situ hybridization), ER-positive (more than 10% of tumor cells expressed estrogen receptor by immunohistochemistry), and PR-positive (at least 1% of tumor cells expressed progesterone receptor by immunohistochemistry) breast cancer; 5.ECOG score is 0-3 points; 6. Expected survival ≥12 weeks; 7. Normal function of major organs:

  1. Blood routine:

     Neutrophil (ANC) ≥1.5×109/L; Platelet count (PLT) ≥75×109/L; Hemoglobin (Hb) ≥90 g/L;

  2. Blood biochemistry:

     Total bilirubin (TBIL) ≤1.5× upper limit of normal (ULN); Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤3.0×ULN; Alkaline phosphatase ≤2.5×ULN; Urea or urea nitrogen (BUN) and creatinine (Cr) ≤1.5×ULN;

  3. Heart color ultrasound:

Left ventricular ejection fraction (LVEF) ≥50%.

Exclusion Criteria:

• 1. Breast cancer with no evaluable lesions such as inflammation or occult; 2. Other malignancies within five years 3. Received other tyrosine kinase inhibitors, anti-HER2 treatment and T-DM1 treatment less than one year ago; 4. Patients with intestinal obstruction or fasting, gastrointestinal history, with diarrhea as the main symptom; 5. Suffering from mental illness or psychotropic substance abuse, unable to cooperate; 6. Pregnant or lactating women; 7. Participants considered unsuitable for inclusion by the researchers.