Efficacy of Nab-PHP Versus TCbHP in Neoadjuvant Therapy for HER2-positive Early Breast Cancer

Inclusion criteria

Age: 18-70 years old.

Clinical Tumor Stage: T2-T4d, or T1c with axillary lymph node positivity.

Histologically confirmed HER2-positive invasive breast cancer:

Note: HER2 positivity is defined as at least one assessment (either initial testing or central review) by the participating center's pathology department demonstrating tumor cells with immunohistochemistry (IHC) staining intensity of 3+ or confirmation by fluorescence in situ hybridization (FISH).

Clinically measurable disease: Lesion measurable by ultrasound or MRI (optional) within 1 month prior to randomization.

Adequate organ and bone marrow function within 1 month prior to chemotherapy initiation (no contraindications to chemotherapy):

• Absolute neutrophil count (ANC) ≥ 2.0 × 10⁹/L
• Hemoglobin ≥ 100 g/L
• Platelet count ≥ 100 × 10⁹/L
• Total bilirubin < 1.5 × upper limit of normal (ULN)
• Serum creatinine < 1.5 × ULN
• Aspartate aminotransferase (AST)/Alanine aminotransferase (ALT) < 1.5 × ULN

Cardiac function: Left ventricular ejection fraction (LVEF) ≥ 55% assessed by echocardiography.

Women of childbearing potential: Negative serum pregnancy test within 14 days prior to randomization.

Performance status: Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

Informed consent: Provision of signed written informed consent.

Exclusion criteria

Stage IV (metastatic) breast cancer.

Bilateral breast cancer.

Prior systemic therapy or radiotherapy for the current breast cancer diagnosis, including chemotherapy, endocrine therapy, or targeted therapy.

History of a second primary malignancy, except for adequately treated non-melanoma skin cancer or carcinoma in situ of the cervix.

Major surgery unrelated to breast cancer within 4 weeks prior to enrollment, or incomplete recovery from prior major surgery.

Significant cardiac disease or dysfunction, including but not limited to:

• History of congestive heart failure or systolic dysfunction (LVEF < 50%)
• High-risk uncontrolled arrhythmias (e.g., atrial tachycardia, resting heart rate > 100 bpm, clinically significant ventricular arrhythmia [e.g., ventricular tachycardia], or higher-grade atrioventricular block [i.e., Mobitz II second-degree or third-degree heart block])
• Angina pectoris requiring anti-anginal medication
• Clinically significant valvular heart disease
• Electrocardiogram (ECG) evidence of transmural myocardial infarction
• Poorly controlled hypertension (systolic blood pressure > 180 mmHg and/or diastolic blood pressure > 100 mmHg)

Presence of any other severe, uncontrolled medical condition that, in the investigator's judgment, constitutes a contraindication to chemotherapy.

Known history of allergy to any component of the study drugs; patients with a history of immune deficiency diseases, including HIV positivity, or patients with other acquired or congenital immune deficiency diseases, or a history of organ transplantation.