LAUSR

e12116 Background: patients with locally-advanced triple negative breast cancer (TNBC) have dismal prognosis with current standard of care therapy. Pathologic complete response (pCR) is the most important prognostic factor for long-term survival of these patients. Methods: this was non-randomized prospective single-center phase II study. Key inclusion criteria were histologically verified locally advanced TNBC, non-eligibility for primary surgical treatment (ie, TNM stage Т2-4N 2-3M0) and no evidence of metastatic disease. Patients were treated with 8 cycles of neoadjuvant doxorubicine, paclitaxel and cisplatin chemotherapy (ATP; doxorubicine 40 mg/m2 day 1, paclitaxel 160 mg/m2 day 1 and cisplatin 50 mg/m2 day 1 every two weeks) with G-CSF support (filgrastim 5 mcg/kg day 2-6). After 8 cycles of chemotherapy patients were referred for surgical treatment; adjuvant radiation therapy was prescribed to all patients. Primary end point was pCR assessed in modified intention-to-treat population (ie, in patients who underwent surgical treatment). Key secondary endpoints were disease-free survival (DFS) and pCR rate according to BRCA status. Results: we enrolled 80 patients, 79 (98.7%) of them underwent surgical treatment and were included in the analysis. Median age was 46 years (25-68), 22 (27.1%) patients had BRCA1 mutations, 5382insC was the most common mutation (17 [77.2%] of patients); 1 (1.2%) patient had CHEK2 mutation. pCR was achieved in 51 (64.5%) patients. In with BRCA1-mutation carriers pCR rate was 61.9%, in patients with 5382insC – 81.2%. 2-year DFS was 77.3%; 2-year overall survival was 91.0% . Most common grade 3-4 adverse events were anemia (29.3%), neutropenia (17.8%), neuropathy (4.9%), stomatitis (3.7%) and thrombocytopenia (1.8%). Conclusions: the ATP regimen was effective in treatment of locally-advanced TNBC, especially in patients with founder 5382insC BRCA1 mutation for Slavic population and deserves further investigation.