A Study of Tislelizumab Combined With TAC Regimen as Neoadjuvant Therapy for TNBC

This study aimed to explore the efficacy and safety of tislelizumab combined with anthracycline- and taxane-based TAC regimen in neoadjuvant treatment for triple-negative breast cancer (TNBC). Whole-exome sequencing and transcriptome sequencing were performed on tumor tissue and peripheral blood samples collected from treated patients to further investigate the underlying molecular mechanisms of this combination therapy.

Inclusion criteria

• 1) Signed written informed consent prior to the initiation of any study-related procedures; 2) Female patients aged 18 to 70 years; 3) Patients with pathologically confirmed primary invasive triple-negative breast cancer (TNBC). TNBC was defined as estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and human epidermal growth factor receptor 2 (HER2)-negative, defined as IHC score of 0 or 1+, or IHC 2+ with negative fluorescence in situ hybridization (FISH) result; 4) Treatment-naive, non-metastatic (M0) TNBC staged according to the 8th edition of the AJCC TNM staging system, with tumor stage of T1N0-2 or T2-4N0-2; 5) Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1; 6) Adequate major organ function within 7 days prior to treatment initiation, meeting the following criteria:

Routine blood tests (without blood transfusion within 14 days):

• Hemoglobin (HB) ≥ 9 g/dL;
• Absolute neutrophil count (ANC) ≥ 1.5 × 10/L;
• Platelet (PLT) count ≥ 100 × 10/L;

Biochemical tests:

• Total bilirubin (TBIL) ≤ 1.5 × upper limit of normal (ULN); or total bilirubin higher than ULN with direct bilirubin ≤ ULN;
• Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 2.5 × ULN;
• Serum creatinine (Cr) ≤ 1.5 × ULN, or creatinine clearance (CCr) ≥ 60 mL/min; 7) For women of childbearing potential, a negative urine or serum pregnancy test within 3 days before the first administration of the study drug (Cycle 1 Day 1) was required. A serum pregnancy test was mandatory if the urine test result was inconclusive. Non-childbearing potential was defined as postmenopausal status for at least 1 year, or history of surgical sterilization or hysterectomy; 8) All patients with fertility potential must adopt contraceptive measures with an annual failure rate lower than 1% throughout the entire treatment period, until 120 days after the last administration of the study drug (or 180 days after the last chemotherapy administration).

Exclusion criteria

• 1) A history of other malignant tumors, or diagnosis of any other malignant disease within 2 years prior to enrollment. Exceptions include basal cell carcinoma or squamous cell carcinoma of the skin, and in situ carcinoma of the cervix or breast that has received radical curative treatment.

• Receipt of chemotherapy, radiotherapy, or targeted therapy within 12 months prior to enrollment.

• Previous participation in clinical studies involving immune checkpoint inhibitors, including anti-PD-1, anti-PD-L1, or anti-CTLA-4 antibodies.

• Known hypersensitivity to the active ingredients or excipients of tislelizumab, albumin-bound paclitaxel, cyclophosphamide, or anthracycline agents.

• Patients who are receiving or planning to receive human papillomavirus (HPV) vaccination during the study period, or those who completed their last HPV vaccination within less than 6 months before enrollment.

• Presence of any severe and/or uncontrolled underlying diseases, including:
• Uncontrolled hypertension with systolic blood pressure ≥ 150 mmHg or diastolic blood pressure ≥ 100 mmHg;
• Grade I or higher myocardial ischemia, myocardial infarction, arrhythmia (including QTc interval ≥ 480 ms), or Grade ≥ 2 congestive heart failure (New York Heart Association [NYHA] classification);
• Active or uncontrolled severe infections;
• Liver cirrhosis, decompensated liver disease, active hepatitis, or chronic hepatitis requiring antiviral treatment;
• Renal failure requiring hemodialysis or peritoneal dialysis;
• A history of immune deficiency diseases, including HIV positivity, other acquired or congenital immune disorders, or a history of organ transplantation;
• Poorly controlled diabetes with fasting blood glucose (FBG) > 10 mmol/L;
• Urinalysis showing urine protein ≥ ++, with a confirmed 24-hour urinary protein quantification > 1.0 g;
• A history of seizure disorders requiring clinical treatment; 7) Imaging evidence of tumor invasion into major blood vessels, or patients judged by the investigator to be at high risk of fatal massive hemorrhage caused by tumor invasion of vital blood vessels during the study period.

• A history of arterial or venous thromboembolic events within 6 months prior to enrollment, including cerebrovascular accidents (transient ischemic attack included), deep vein thrombosis, and pulmonary embolism.

• A history of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within 6 months prior to enrollment.

• Subjects with any signs or history of bleeding diathesis regardless of severity; subjects with any bleeding events of CTCAE Grade ≥ 3 within 4 weeks before the first study drug administration; or subjects with unhealed wounds, fractures, active gastroduodenal ulcers, ulcerative colitis, unresected tumors with active bleeding, or other conditions judged by the investigator to carry risks of gastrointestinal bleeding or perforation.

• Uncontrolled pleural effusion, pericardial effusion, or ascites requiring repeated drainage.

• Participation in other clinical trials of anti-tumor drugs within 4 weeks prior to enrollment.

• Presence of any concomitant disease that may seriously endanger patient safety or interfere with study completion, as judged by the investigator.