This is a single-center, single-arm, prospective study enrolling 30 patients with stage II-III triple-negative breast cancer. The neoadjuvant regimen consists of QL1706 combined with carboplatin plus albumin-bound paclitaxel (21-day cycles for 4 cycles) followed by QL1706 combined with doxorubicin/epirubicin plus cyclophosphamide (21-day cycles for 4 cycles). The treatment observation period is 1 year, and the primary endpoint is the pathological complete response rate.

Inclusion Criteria:

1. Histologically or cytologically confirmed newly diagnosed ER-/HER2- breast cancer. ER and PR with Allred score <3 or <1% positively stained cells in tumor infiltrating components. HER2 negativity defined as 0 or 1+ by FISH or IHC staining per NCCN guidelines;
2. Clinical stage II or III breast cancer eligible for neoadjuvant chemotherapy (per AJCC 8th edition: at least T2 any N M0, or any T if N+), with treatment goal of complete surgical resection following neoadjuvant therapy;
3. Tumor size ≥2 cm by clinical or imaging assessment per WHO criteria. Patients with histologically confirmed or clinically palpable lymph nodes are eligible regardless of tumor size;
4. Treatment-naïve subjects;
5. Age ≥18 years, both genders eligible;
6. ECOG performance status 0-1;
7. Adequate bone marrow, cardiac, and organ function;
8. Women of childbearing potential must have a negative pregnancy test (serum or urine HCG) within 30 days prior to study enrollment and must practice effective contraception during the study;
9. Ability to comprehend and provide written informed consent.

Exclusion Criteria:

1. History of invasive malignancies within 5 years prior to signing the informed consent form, except for adequately treated basal cell carcinoma, squamous cell skin cancer, or carcinoma in situ of the cervix;

2. Subjects who have received chemotherapy, immunotherapy, targeted therapy, or radiotherapy within the past 12 months;

3. Stage IV metastatic breast cancer;

4. Administration of a vaccine within 30 days before the first dose of the study treatment;

5. Subjects with severe systemic diseases;

6. Subjects with active infections (including but not limited to HIV, hepatitis B or C, tuberculosis);

7. Severe cardiovascular diseases, such as: history of myocardial infarction, acute coronary syndrome, or coronary angioplasty/stenting/bypass grafting within the past 6 months; or congestive heart failure (CHF) of New York Heart Association (NYHA) class II-IV, or history of CHF NYHA class III or IV;

8. Lactating women should discontinue breastfeeding during the study;

9. Subjects with known allergies to the study drug or any of its excipients;

10. Any other condition deemed inappropriate for participation in the study by the investigator.

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