Adding sunitinib to standard doses of bevacizumab plus paclitaxel for metastatic breast cancer is not feasible. Different strategies will be required to evaluate whether there is additional clinical benefit to combining VEGF/VEGFR-targeted agents.

Introduction: Patients with triple negative breast cancer (TNBC) have a worse prognosis compared to other breast cancer subtypes, primarily due to lack of targeted treatment options. EGFR1 (epidermal growth factor receptor) is often over-expressed in TNBC and could be a promising therapeutic target. Clinical studies have shown platinums and taxanes to be effective in TNBC and in vitro data has demonstrated synergy between carboplatin, docetaxel and an EGFR inhibitor in TNBC cell lines. Aim: To evaluate the efficacy of platinum/taxane based chemotherapy in combination with a small molecule EGFR inhibitor, Erlotinib, in patients with TNBC. Methods: Patients with stage II/III TNBC were eligible for this phase II trial. All patients received 6 cycles of chemotherapy (Carboplatin AUC 6, Docetaxel 75mg/m2 every 21 d). In addition patients were equally randomized between two erlotinib arms. Patients in arm A received Erlotinib (150 mg PO d 3 - 14 every 21 d) during all 6 cycles of chemotherapy & patients in arm B received erlotinib only during the last 4 cycles of chemotherapy. This randomization was intended to reduce bias in the evaluation of the effect of erlotinib on biomarkers in a core biopsy of the tumor performed after the second cycle of chemotherapy. All but one patient underwent comprehensive BRCA analysis (Myriad Genetic Laboratories). Following neo-adjuvant therapy, all patients underwent breast surgery. The primary end point was pathological complete response (pCR: no evidence of invasive tumor in the breast & axilla). Minimal Residual Disease [MRD= Residual Cancer Burden (RCB) groups 0+1] status was also evaluated. Results: 30 eligible patients with TNBC were enrolled between 8/2007 and 6/2010. This analysis includes 28 patients since 2 patients are still on study treatment. Median age: 51yrs (range 31-68), 21%: African American, 54%: postmenopausal. Median tumor size was 3.3 cm & 39% had LN+ disease. Fifteen patients were assigned to each arm of erlotinib. Five of 28 patients (17%) carried a BRCA mutation (two BRCA1deleterious, two BRCA2 deleterious, one BRCA1 uncertain). The overall pCR and MRD (RCB 0+1) rates were 39% & 50% respectively. On univariate analysis, tumor size, LN status, menopausal status, age and number of erlotinib cycles did not correlate with pCR. However, BRCA mutation status strongly correlated with pCR, with a pCR rate of 100% in BRCA mutation carriers compared to 27% in those without BRCA mutation (p=0.006). Baseline EGFR and/or p53 expression of ≥10% was associated with a lower pCR rate in BRCA non-carriers (pCR: 12% vs. 66%, p = 0.025). Common Erlotinib related AEs were: rash (G3/4:7%) & diarrhea (G3/4:30%) with 32% of subjects requiring erlotinib dose reduction/discontinuation due to AEs. Conclusions: Pathological complete response rates of TNBC to a combination of platinum/taxane chemotherapy & an oral EGFR inhibitor are encouraging and should be explored further. The response to this regimen was significantly influenced by BRCA mutation status, indicating a need to stratify patients by their BRCA status in future TNBC trials. Tissue biomarker analysis of downstream targets of EGFR inhibition should be informative regarding the exact role of erlotinib in this patient population. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-11-07.

Introduction: Triple negative breast cancer (TNBC) and BRCA1-associated breast cancers share many histopathologic and molecular features. BRCA1 plays a crucial role in HR-dependent DNA repair and BRCA1-deficient cells are particularly susceptible to the DNA damaging agents like platinums. Increasing evidence suggests that in addition to germline BRCA defects, other mechanisms (like epigenetic BRCA1 silencing) can lead to BRCA1 insufficiency in TNBC. However, the impact of BRCA1 insufficiency on the efficacy of DNA damaging agents in TNBC is not known. Aim: To investigate the impact of BRCA1 insufficiency on relapse-free survival (RFS) and overall survival (OS) in patients with stage II-III TNBC treated with neoadjuvant platinum-based chemotherapy. BRCA1 insufficiency (BRCA1insuf) state was defined as presence of germline BRCA1/2 mutation or BRCA1 promoter methylation (PM) and/or low BRCA1 expression (lowest quartile). Methods: Thirty patients with stage II/III TNBC received neoadjuvant chemotherapy (6 cycles of Carboplatin AUC 6, Docetaxel 75mg/m2 and Erlotinib 150 mg PO) on a phase II trial between 8/2007–6/2010. All but one patient underwent comprehensive BRCA analysis (Myriad Genetic Laboratories). Pre-treatment tumor specimens were used for evaluation of BRCA1 PM and expression. Genomic DNA was isolated from FFPE samples, bisulfite converted and then subjected to methylation-specific PCR (MSP). RNA was isolated, reverse transcribed to cDNA and assayed by quantitative real-time PCR (qRT-PCR) for determination of BRCA1 mRNA transcript levels. RFS and OS were estimated according to the Kaplan-Meier method and compared among groups with log-rank statistic. Cox proportional hazards models were fit to determine the association of BRCA1insuf with the risk of death after adjustment for other characteristics. Results: Median age: 51yrs, African American: 20%, Median tumor size: 3.3 cm, LN positive: 40%. Six of 30 patients (20%) harbored germline BRCA mutation (4 BRCA1, 2 BRCA2). Baseline tumor specimen was available for 26/30 patients. BRCA1 MSP was successful in 92% and BRCA1 qRT-PCR was successful in 84% of specimens. BRCA1 PM and low BRCA1 expression was present in 30% and 15% of subjects, respectively. There was evidence of BRCA1insuf in 53% (16/30) of subjects. At a median time from diagnosis of 42 months (range, 23–59 months) there have been 9(30%) recurrences and 7(23%) deaths. On univariate analysis node negativity, lower stage and presence of BRCA1insuf were associated with better OS. At the median follow up, RFS is 81% for patients with BRCA1insuf versus 54% for patients without BRCA1insuf (p = 0.16); OS is 83% for patients with BRCA1insuf versus 46% for patients without BRCA1insuf (p = 0.021). After adjustment for clinical variables patients with BRCA1insuf had a significantly better OS compared to patients without BRCA1insuf (p = 0.036). Conclusions: Germline BRCA testing plus tissue BRCA1 PM/expression can be used to identify a BRCA1insuf sub-population within TNBC demonstrating a favorable outcome with platinum treatment. This BRCA1insuf criteria can be easily used to select TNBC patients likely to benefit from DNA damaging agents like platinums and PARP inhibitors. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD09-02.

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