Bevacizumab plus preoperative chemotherapy in operable HER2 negative breast cancer: biomarkers and pathologic response.

PURPOSE: The primary aim of this trial was to assess the rate of pathologic complete responses (pCR) of doxorubicin/cyclophosphamide (AC) followed by bevacizumab/docetaxel (BT), as neoadjuvant therapy for breast cancer (BC). Furthermore, the association between biomarkers and the pCR was explored.

METHODS: Patients with HER-negative operable stage II-III BC ≥ 2 cm were enrolled. Four cycles of AC (A 60 mg/m(2) and C 600 mg/m(2), every 3 weeks) followed by 4 cycles of BT (B 15 mg/kg and T 75 mg/m(2), every 3 weeks), were planned. A core-biopsy was performed for biological markers assessment.

RESULTS: Seventy-two women were included. Forty-three (63 %) patients were hormone receptor-positive. Sixty-four (89 %) completed the planned treatment, and 66 evaluable patients underwent surgery (92 %): a pCR was achieved in 16 of them (24, 95 % CI 15-36 %). pCR was significantly higher in tumors hormone receptor-negative, and in those with Angiotensin II type 1 receptor (AGTR1) protein overexpression. The overall clinical response rate was 86 % (95 % CI 76-93 %), including 42 complete responses. No unexpected toxicities or treatment-related deaths were observed.

CONCLUSION: This regimen showed a remarkable clinical and pathological activity: the suggested relation between pCR and AGTR1 overexpression should be confirmed in larger trials.