Abstract P1-01-19: Circulating tumor cells in triple-negative breast cancer patients express prostate related genes and show different genetic profiles in US and German patient cohorts

Background: Triple negative breast cancer (TNBC) is known for its aggressive behavior and poor prognosis since treatment options are limited. Specific biomarkers are urgently needed to treat patients (pts) accordingly. In this regard, circulating tumor cells (CTCs) are discussed to be an ideal surrogate marker for individualized treatment options. Using a multi-marker gene panel for the characterization of CTCs, we recently demonstrated that CTCs in TNBC pts and non-TNBC pts showed different genetic profiles including the expression of the androgen receptor (AR). We here compared CTCs of TNBC pts in two different national Institutions in the US (mainly Afro-American women) and Germany (Caucasian women) to identify potentially ethnical differences and to further explore AR expression related similarities of prostate cancer to TNBC.

Methods: 2x5 ml blood of TNBC pts before therapy (n=18 from the Dep. of Gynecol. and Obstetrics, Essen, GER; n=31 from the MDA Cancer Center Houston, US) were analyzed for CTCs applying positive immunomagnetic selection targeting EpCAM, EGFR and HER2 using the AdnaTest EMT-2/Stem Cell Select (QIAGEN Hannover GmbH, Germany). Subsequently, cDNA was pre-amplified for specific genes using TaqMan PreAmp Master Mix according to in house designed assays. Establishment of a 19 gene qPCR panel was performed for the markers PI3K, AKT2, ERCC1, AURKA, HER2, HER3, EGFR, ALK, AR, BRCA1, c-KIT, c-MET, KRT5, mTOR, NOTCH1, PARP1, SRC1, CD45 (leucocyte control) and GAPDH (housekeeping gene) as well as an internal reference. The cutoff was calculated, taking the false positive rate in healthy donors into account, and defined as Ct (cutoff) - Ct (sample) - [Ct (CD45cutoff) – Ct (CD45sample)]. Using the AdnaPanel Prostate Cancer (QIAGEN Hannover GmbH, Germany), cDNA obtained from a subset of 14 pts was further analyzed for the expression profile of AR, prostate specific antigen (PSA) as well as prostate specific membrane antigen (PSMA).

Results: The overall CTC-positivity rate (at least one of the markers expressed) was comparable between both sites (GER: 78%; US: 65%). Similar overexpression frequencies were found for AKT2, AR, AURKA, c-KIT, NOTCH1 and SRC at both sites. However, ALK, BRCA1, HER3 and KRT5 were predominantly found in CTCs of German pts while these genes were not or only weakly expressed in CTCs of the US group. In contrast, c-MET, ERCC1, HER2 and PARP were mainly expressed in CTCs of the US group and rarely in the German group. Interestingly, EGFR was not detected in both groups. Analyzing the overexpression of prostate related genes in a subgroup of 14 TNBC pts resulted in the expression of AR in 21%, PSA in 14%, and PSMA in 36% of cases, respectively.

Conclusion: Although we observed similar gene expression profiles in both patient cohorts, clear differences in some gene expression frequencies were detected at both sites. Whether these findings can be related to ethnic differences will be subject of further investigations. Furthermore, we were able to demonstrate that prostate related genes were frequently detectable which so far have not been discussed in the context of breast cancer.

Citation Format: Kasimir-Bauer S, Gao H, Bittner A-K, Plappert L, Feniuk N, Ueno NT, Cohen L, Valero V, Woodward WA, Alvarez RH, Hoffmann O, Kimmig R, Reuben JM. Circulating tumor cells in triple-negative breast cancer patients express prostate related genes and show different genetic profiles in US and German patient cohorts [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-01-19.

Abstract P6-09-23: SETER/PR - A robust 18-gene predictor of sensitivity to endocrine therapy in metastatic breast cancer

Rationale: A robust index for gene expression related to activity of estrogen (ESR1) and progesterone (PGR) receptors could predict sensitivity to endocrine therapy in metastatic breast cancer.

Methods: Transcripts correlated with ESR1 and PGR expression in 389 hormone receptor-positive breast cancer samples (Affymetrix U133A microarrays) were ranked for reliability according to their pre-analytical (intratumoral heterogeneity, biopsy type) and analytical reproducibility. Eighteen target and ten reference genes were selected and summarized as the SETER/PR index. The SETER/PR index was evaluated in a different set of 140 biopsies from distant metastases of hormone receptor-positive and HER2-negative (HR+/HER2-) breast cancer, and in additional pre-analytical and analytical sample cohorts. Thereafter, SETER/PR was translated to a customized format for application to formalin-fixed and paraffin-embedded (FFPE) sections.

Results: Higher SETER/PR in a metastasis was associated with longer progression-free survival (PFS, 9 vs. 2 months) and overall survival (OS, 50 vs. 19 months) following endocrine therapy in the cohort with metastatic breast cancer (MBC) and relapsed disease (n=79), so a cut point was defined in that cohort. SETER/PR was also significantly associated with PFS after adjusting for PR status of the metastasis, presence of visceral metastases, number of previous relapse events, and clinical history of previous sensitivity to endocrine therapy (HR 0.485, 95%CI 0.265 – 0.889, p = 0.019). Technically, SETER/PR was highly reproducible under different pre-analytical and analytical conditions, including host organ contamination. The translated SETER/PR assay used a single 10 µm FFPE tissue section, did not require RNA purification, and represented the microarray results from matched fresh samples with excellent agreement (correlation = 0.980, n = 31).

Conclusion: The SETER/PR index is a new biomarker to predict PFS and OS for patients with HR+/HER2- MBC who receive endocrine therapy. The assay is applicable to FFPE tissue sections from small biopsies of metastases. Additional independent (blinded) validation studies will be necessary to confirm these results.Rationale: A robust index for gene expression related to activity of estrogen (ESR1) and progesterone (PGR) receptors could predict sensitivity to endocrine therapy in metastatic breast cancer.

Methods: Transcripts correlated with ESR1 and PGR expression in 389 hormone receptor-positive breast cancer samples (Affymetrix U133A microarrays) were ranked for reliability according to their pre-analytical (intratumoral heterogeneity, biopsy type) and analytical reproducibility. Eighteen target and ten reference genes were selected and summarized as the SETER/PR index. The SETER/PR index was evaluated in a different set of 140 biopsies from distant metastases of hormone receptor-positive and HER2-negative (HR+/HER2-) breast cancer, and in additional pre-analytical and analytical sample cohorts. Thereafter, SETER/PR was translated to a customized format for application to formalin-fixed and paraffin-embedded (FFPE) sections.

Results: Higher SETER/PR in a metastasis was associated with longer progression-free survival (PFS, 9 vs. 2 months) and overall survival (OS, 50 vs. 19 months) following endocrine therapy in the cohort with metastatic breast cancer (MBC) and relapsed disease (n=79), so a cut point was defined in that cohort. SETER/PR was also significantly associated with PFS after adjusting for PR status of the metastasis, presence of visceral metastases, number of previous relapse events, and clinical history of previous sensitivity to endocrine therapy (HR 0.485, 95%CI 0.265 – 0.889, p = 0.019). Technically, SETER/PR was highly reproducible under different pre-analytical and analytical conditions, including host organ contamination. The translated SETER/PR assay used a single 10 µm FFPE tissue section, did not require RNA purification, and represented the microarray results from matched fresh samples with excellent agreement (correlation = 0.980, n = 31).

Conclusion: The SETER/PR index is a new biomarker to predict PFS and OS for patients with HR+/HER2- MBC who receive endocrine therapy. The assay is applicable to FFPE tissue sections from small biopsies of metastases. Additional independent (blinded) validation studies will be necessary to confirm these results.

Citation Format: Sinn BV, Tsai T-H, Lau R, Fu C, Gould R, Murthy R, King TA, Hatzis C, Kwiatkowski DN, Valero V, Symmans WF. SETER/PR - A robust 18-gene predictor of sensitivity to endocrine therapy in metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-23.

Clinicopathological and surgical factors associated with long-term survival in patients with HER2-positive metastatic breast cancer

Trastuzumab-based treatment has dramatically improved the outcomes of HER2-positive (HER2+) metastatic breast cancer (MBC) patients, with some patients achieving prolonged survival times. In this study, we aim to identify factors that are associated with long-term survival. Patients with HER2+ MBC treated with anti-HER2 target therapy were identified. Patients were grouped according to overall survival (OS) and categorized as long-term survivors (LTS, OS ≥ 5 years), or non-long-term survivors (non-LTS, OS < 5 years). Descriptive statistics and multivariable logistic regression modeling were used. A sensitivity analysis was carried out, including only patients diagnosed before 2007; therefore, 5 years of potential follow-up was possible. 1063 patients with HER2+ MBC diagnosed between 1994 and 2012 and treated with anti-HER2 therapy were identified. Among them, 154 (14.5 %) patients were categorized as LTS (median OS 92.2 months). Among LTS, 63.4 % were HR-positive and 32 % had de novo stage IV disease. Hormone receptor positivity (OR) 1.69; 95 % CI 1.17-2.44), resection of metastases (OR 2.38; 95 % CI 1.53-3.69), and primary breast surgery in patients with de novo stage IV (OR 2.88; 95 % CI 1.47-5.66) were associated with improved long-term survival. Greater number of metastatic sites (≥3 vs. 1, OR 0.41; 95 % CI 0.23-0.72) and visceral metastases (OR 0.61; 95 % CI 0.4-0.91) were associated with poor survival. Hormone receptor positivity, low burden of disease, metastasis to soft and bone tissues, and surgical management with resection of the metastatic site and the primary tumor were associated with long-term survival in patients with MBC who received anti-HER2 treatment.

Circulating Tumor Cells (CTC) Are Associated with Defects in Adaptive Immunity in Patients with Inflammatory Breast Cancer

Background: Circulating tumor cells (CTCs) play a crucial role in tumor dissemination and are prognostic in primary and metastatic breast cancer. Peripheral blood (PB) immune cells contribute to an unfavorable microenvironment for CTC survival. This study aimed to correlate CTCs with the PB T-cell immunophenotypes and functions of patients with inflammatory breast cancer (IBC).

Methods: This study included 65 IBC patients treated at the MD Anderson Cancer Center. PB was obtained from patients prior to starting a new line of chemotherapy for CTCs enumeration by CellSearch^®, and T cell phenotype and function by flow cytometry; the results were correlated with CTCs and clinical outcome.

Results: At least 1 CTC (≥1) or ≥5 CTCs was detected in 61.5% or 32.3% of patients, respectively. CTC count did not correlate with total lymphocytes; however, patients with ≥1 CTC or ≥5 CTCs had lower percentages (%) of CD3+ and CD4+ T cells compared with patients with no CTCs or <5 CTCs, respectively. Patients with ≥1 CTC had a lower percentage of T-cell receptor (TCR)-activated CD8+ T cells synthesizing TNF-α and IFN-γ and a higher percentage of T-regulatory lymphocytes compared to patients without CTCs. In multivariate analysis, tumor grade and % CD3+ T-cells were associated with ≥1 CTC, whereas ≥5 CTC was associated with tumor grade, stage, % CD3+ and % CD4+ T cells, and % TCR-activated CD8 T-cells synthesizing IL-17.

Conclusions: IBC patients with CTCs in PB had abnormalities in adaptive immunity that could potentially impact tumor cell dissemination and initiation of the metastatic cascade.

Abstract P1-14-04: A randomized phase II neoadjuvant (NACT) study of sequential eribulin followed by FAC/FEC-regimen compared to sequential paclitaxel followed by FAC/FEC-regimen in patients (pts) with operable breast cancer not overexpressing HER-2

Background: Neoadjuvant chemotherapy (NACT) is an integral component for locally advanced and large operable breast cancer. The sequence of taxanes followed by anthracyclines has been the standard of care for almost 20 years. Eribulin (E) is a synthetic analogue of halichondrin B with distinct mechanism of action as microtubule dynamics inhibitor. The FDA approved E in 11/2010 for the treatment of patients (pts) with metastatic breast cancer who have previously received at least two chemotherapeutic regimens for the treatment of metastatic disease. Research Hypothesis: Sequential administration of eribulin followed by FAC/FEC-regimen, would have greater pathologic complete response (pCR) rate than sequential administration of paclitaxel followed by FAC/FEC-regimen as primary systemic therapy for woman with operable breast cancer.

Methods: This is a phase II, randomized, single institution, open label study. Pts were randomized 1:1 to receive E (1.4 mg/m2 d1 and d8 q 21 days x 4) or paclitaxel (P) (80 mg/m2 weekly x12). Both arms received FAC/FEC regimen x 4 doses followed by surgery. Eligible pts were women age 18 or older, Karnosfky PS 80 – 100, histologically confirmed invasive breast cancer, clinical T2-T3, N0-3, M0, HER2-negative. Baseline LVEF of &gt; 50% and normal hematology, liver and kidney laboratory function tests. Primary endpoint was pathologic complete response (pCR/RCB-0) assessed by residual cancer burden (RCB). [Symmans F, 2007]. This protocol (2012-0167) IRB of The University of Texas, MD Anderson Cancer Center.

Results: A preplanned interim analysis aimed to validate trial assumption was conducted after treatment of 54 randomized pts. Between 8/2012 to 7/2014, 54 pts were randomized and 49 were evaluable for pCR(27 P arm and 22 E arm). Tumor response by RCB is shown in the table. pCR rates were 30% and 4.5% in the P and E arm, respectively.

Table 1.ResponsePaclitaxel - FAC/FEC Arm (N=27)Eribulin - FAC/FEC Arm (N=22)RCB 0 (pCR)8 (30%)1 (4.5%)RCB I6 (22.2%)1 (4.5%)RCB II9 (33%)10 (45%)RCB III4 (14.8%)10 (45%)

53 pts were evaluable for toxicity. The combination was safe with mostly grade 1 and 2 toxicities in both arms. In the P arm grade 3 peripheral neuropathy and neutropenia was seen in 3% and 7%, respectively. In the E arm one patient died due to multiorgan failure during cycle 1. There was no other grade 3-5 toxicity. Biomarker analysis using CTCs by AdnaTest Breast were evaluated in 39 pts at baseline. 5/39 pts were positive for CTCs. 3 pts had transcripts for EpCAM, 1 for Muc-1 and another had both. 30 pts had an additional sample post therapy. 2 pts were positive for CTC at baseline as well as at follow up (FU) visit at 180 days. None of the samples showed CTC-EMT at baseline or at FU visits.

Conclusions: The interim analysis demonstrated that E arm lead to significantly lower pCR/RCB1 rate compared to P arm. Ongoing biomarker analyses include TIL, hot spot mutation analysis (HSMA) and molecular inversion probes (MIP) will be presented at the time of the meeting. Clinical trial information: NCT01593020.

Citation Format: Alvarez RH, Koenig KB, Ensor JE, Ibrahim NK, Chavez-MacGregor M, Litton JK, Schwartz Gomez JK, Cyriac A, Krishnamurty S, Caudle AS, Shaitelman SF, Whitman GJ, Booser DJ, Reuben JM, Valero V. A randomized phase II neoadjuvant (NACT) study of sequential eribulin followed by FAC/FEC-regimen compared to sequential paclitaxel followed by FAC/FEC-regimen in patients (pts) with operable breast cancer not overexpressing HER-2. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-14-04.

Abstract P4-04-18: High serum miR-19a levels correlated with favorable prognosis in patients with metastatic HER2+ breast cancer and might result from effective antibody-dependent cell-mediated cytotoxicity (ADCC) induced by trastuzumab and Th1-mediated antitumor immune response

Introduction

HER2 amplification is found in up to 20% of breast cancer and is associated with poor survival. To date, no predictive biomarker has been validated for clinical practice in patients with HER2+ breast cancer. Type 1 T helper lymphocytes (Th1) are required to activate antitumor cytotoxic T lymphocytes (CTL) necessary for tumor clearance. Particularly, IFN-γ secreted by Th1 cells is necessary for the development of CTL-mediated antitumor response. Trastuzumab can induce antibody-dependent cell-mediated cytotoxicity (ADCC) mediated by natural killer (NK) cells. In turn, trastuzumab-activated NK cells can trigger Th1 cells by driving their differentiation and maturation. Furthermore, NK-mediated ADCC can increase tumor cell membrane permeability through pore formation induced by perforin secreted by NK cells.

We found that: 1) high serum miR-19a levels in patients with metastatic HER2+ breast cancer were predictive of favorable prognosis; 2) Th1 cells expressed and secreted high miR-19a levels; 3) and breast cancer tissue expressed higher miR-19a levels than normal adjacent tissue. Therefore, the high serum miR-19a levels in patients with good prognosis may derive from tumor cells killed by NK-mediated ADCC and secretion from Th1 cells. MiR-19a may represent a marker of effective anti-tumor immune response.

Results

HER2+ metastatic breast cancer patients with high serum miR-19a levels (n=27) had longer PFS (7.9 vs. 4.1 months; p=0.003) and OS (median not reached vs. 13.1 months; p&lt;0.0001) than patients with low serum miR-19a levels (n=24). Locally advanced breast cancer tissue (n=35) expressed higher levels of miR-19a than normal adjacent tissue (n=10) (p=0.048). KPL-4 cells (HER2-amplified) expressed higher miR-19a levels than SKBR3 cells (HER2-amplified) (p=0.010) and MCF-7 cells (non-HER2-amplified, used as control) (p&lt;0.0001). In in vitro ADCC assay, trastuzumab induced an increased tumor cell killing by NK cells and consequent miR-19a release into the supernatants of MCF-7 (p=0.004; p=0.0005), SKBR3 (p=0.001; p&lt;0.0001) and KPL-4 (p=0.0005; p&lt;0.0001), respectively. Th1 cells expressed (p&lt;0.0001) and secreted (p=0.0002) higher miR-19a levels than Th2 cells (Th1 antagonist). Patients with favorable prognosis had higher levels of IFN-γ-secreting Th1 cells (p=0.049) in the peripheral blood than patients with worse prognosis.

Conclusion

High serum miR-19a levels in patients with metastatic HER2+ breast cancer may result from an increased ability of trastuzumab to induce an effective NK-mediated ADCC and activation of Th1-mediated immune response. This may explain the different clinical outcome between patients with high and low serum miR-19a levels. Our results suggest that miR-19a may potentially represent a novel serum biomarker to evaluate trastuzumab response and Th1-mediated anti-tumor immunity in patients with metastatic HER2+ breast cancer.

Citation Format: Anfossi S, Huo L, Woodward WA, Ueno NT, Valero V, Calin GA, Reuben JM. High serum miR-19a levels correlated with favorable prognosis in patients with metastatic HER2+ breast cancer and might result from effective antibody-dependent cell-mediated cytotoxicity (ADCC) induced by trastuzumab and Th1-mediated antitumor immune response. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-04-18.

Abstract OT2-03-03: Women's triple-negative, first-line treatment: Improving outcomes in triple-negative breast cancer using molecular triaging and diagnostic imaging to guide neoadjuvant therapy

BACKGROUND:

In triple negative breast cancer (TNBC), pathologic compete response/residual cancer burden-0 (pCR/RCB-0) or minimal residual disease (RCB-I) following neoadjuvant chemotherapy (NACT) is associated with a good prognosis. This is in contrast to extensive residual disease (RCB-II-III) which carries approximately a 50% chance of recurrence. These patients have a particularly poor prognosis as there are currently no targeted agents to salvage chemoresistant disease. It is important to predict pCR in order to direct responsive disease toward standard NACT and non-responsive disease (NRD) to therapy on clinical trials.

TRIAL DESIGN:

The use of genomic signatures (JAMA, 2011; 305:1873-81) and imaging to predict response to NACT will be validated, and the clinical impact of selecting patients with predicted NRD for targeted therapy on clinical trial will be determined. Patients will undergo primary tumor biopsy for molecular profiling and will be randomized 2:1 to know the results versus not (control). Following that, all patients will receive 4 cycles of anthracycline-based NACT, with imaging used for response assessment. Patients with molecular/imaging criteria for NRD will be offered enrollment on a clinical trial based upon molecular profiling or based upon physician/patient choice (control).

INCLUSION CRITERIA:

Tumor size ≥1.5 cm diameter; TNBC by standard assays; ≥18 years of age; LVEF ≥50%; adequate organ and bone marrow function

EXCLUSION CRITERIA:

Stage IV disease; invasive cancer within 5 years; excisional biopsy of the primary tumor; features that limit response assessment by imaging; unfit for taxane and/or antracycline regimens; prior anthracycline therapy; ≥grade II neuropathy; Zubrod performance status of ≥2; history of serious cardiac events

PRIMARY AIM:

- Prospectively determine the impact of a molecular diagnostic/imaging platform in patients with localized invasive TNBC

SECONDARY AIMS:

- Compare rates of clinical trial enrollment

- Evaluate disease free survival in the experimental arms compared to control standard NACT

- Perform integrated biomarker analyses and identify therapeutic targets for resistant disease

STATISTICAL METHODS:

A maximum of 360 patients will be randomized (2:1)using a group sequential design with one-sided O'Brien-Fleming boundaries, with two equally spaced binding interim tests for futility and superiority and one final test, having an overall Type I error .05 and power .80 to detect an improvement in pCR/RCB-I from 50% to 64%.

Citation Format: Mitri ZI, Ueno NT, Yang W, Valero V, Litton JK, Murthy RK, Ibrahim NK, Arun BK, Mittendorf EA, Hunt KK, Meric-Bernstam F, Thompson A, Piwnica-Worms H, Tripathy D, Symmans F, Moulder-Thompson S. Women's triple-negative, first-line treatment: Improving outcomes in triple-negative breast cancer using molecular triaging and diagnostic imaging to guide neoadjuvant therapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT2-03-03.

Abstract P4-10-09: Relapse-free survival of triple negative breast cancer long term survivors and characterization of late events in MD Anderson experience

Background:

Stage I-III TNBC patients have a high risk of disease relapse during the first 5 years after diagnosis. However, there is limited data on the risk of late relapse in TNBC survivors who are disease free at 5 years or more from diagnosis. We sought to characterize this risk in a cohort of TNBC long-term survivors from a large institutional database.

Methods:

The MD Anderson Breast Cancer Management System database was queried for TNBC survivors who were disease free 5 years or more from diagnosis. Demographic, tumor, and treatment data was extracted. Electronic medical records were searched to confirm pathology reports for invasive breast cancer diagnosis, triple negative receptor status, and hormone receptor percentage (%). The primary and secondary outcomes of interest were relapse free survival (RFS) and distant relapse free survival (DRFS). Patients were censored at time of developing a second primary breast cancer or at last follow-up time for those who were alive during the study. We used ACP-ASCO definition of ER and PR &lt;1% and HER2/neu negative (IHC 0-1 or ratio &lt;2 and average copy number &lt;4) but also included patients with low ER/PR(1-9%) and HER2 normal. Kaplan-Meier analysis was performed to compare RFS and DRFS for the overall population and categorized by ER/PR &lt;1%, and ER/PR 1-9%.

Results:

We identified 1038 patients who had a median follow-up of 8.0 years. Receptor % information was available on 69% of patients, with 78% of them meeting current TNBC definition. From the total cohort of 130, 12.5% suffered event(s) that occurred after 5 years from diagnosis, with 86.2% of them occurring within 5-10 years of diagnosis. The event rate was 16.4% among patients with ER/PR 1-9% versus 11.3% among patients with ER/PR &lt;1%. Table 1 shows RFS and DRFS by year from diagnosis for the entire cohort and categorized by % receptor. 18 patients developed second primary breast cancer as first event and were censored. Of total events recorded, 53(40.8%) were deaths and 77(59.2%) were recurrences, of which 51(66%) were distant and 26(34%) local, of whom 12(46.2%) subsequently developed distant metastases. Among patients who initially presented with distant recurrence, frequencies of initial sites of metastases are shown in Table 2.

Conclusions:

TNBC long term survivors are still at risk for relapse events after 5 years from diagnosis, and it is important to quantity this risk when counseling our patients. Frequency of late events was higher among patients with low hormone receptor positivity. Multivariate modeling of predictors of late recurrence is ongoing.

Table 1: RFS and DRFS by Year from Diagnosis All PatientsER/PR &lt;1%ER/PR 1-9%Year From DiagnosisRFSDRFSRFSDRFSRFSDRFS4-51.01.01.01.01.01.05-60.950.960.940.950.940.956-70.930.940.930.940.910.927-80.900.920.900.920.870.898-90.860.880.870.890.810.849-100.840.870.840.860.800.8310-120.810.840.810.830.800.8312-150.730.780.730.750.670.74

Table 2: Site of Initial Distant RecurrenceSiteN (%)Lung/Pleura28 (54.9)Bone19 (37.3)Distant Lymph Nodes19 (37.3)Liver11 (21.6)Brain/Spinal Cord8 (15.7)Colorectal/Pancreas/Kidney/Adrenal6 (11.7)Other2 (3.9)*Patients presenting with multiple sites of distant recurrence are counted in each category.

Citation Format: Reddy SM, Sinha A, Syed M, Barcenas C, Valero V. Relapse-free survival of triple negative breast cancer long term survivors and characterization of late events in MD Anderson experience. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-10-09.

Abstract P3-14-02: Targeting the PI3K/AKT/mTOR pathway for the treatment of mesenchymal triple-negative breast cancer (TNBC): Evidence of efficacy and proof of concept from a phase I trial with dose expansion of mTOR inhibition in combination with liposomal doxorubicin and bevacizumab

Background: Approximately 30% of TNBCs are characterized by microarray as claudin-low, mesenchymal or mesenchymal stem cell-like and, unlike basal TNBCs, these tumors frequently harbor aberrations in the PI3K/AKT/mTOR axis, raising the possibility of targeting this axis to enhance chemotherapy response. Assays to clinically identify mesenchymal TNBCs are under development, but published results confirm that up to 30% are metaplastic breast cancers (MpBCs), a chemo-refractory group of tumors that contain a mixture of epithelial and mesenchymal components, making them identifiable by microscopy. As such, MpBCs serve as surrogates of response for potential regimens to treat mesenchymal TNBC.

Methods: Patients (pts) with advanced TNBC (N=64) were treated with liposomal doxorubicin (D), bevacizumab (A) and the mTOR inhibitors temsirolimus (T) or everolimus (E). D and A were administered IV on day 1 with T (IV on days 1, 8 and 15) or E (continuous daily oral administration) using 21 day cycles. Response was assessed every 6 weeks using RECIST. When available, archived tissue was evaluated for aberrations in the PI3K pathway using standard assays.

Results: Fifty-two MpBC pts were treated with DAT (N=39) or DAE (N=13). Median age was 58 (range 37-79); median # of prior regimens for metastatic disease was 1 (range 0-5). The objective response rate (ORR) was 21% [complete response (CR)=4 (8%); partial response (PR)=7 (13%)] and 10 (19%) pts had stable disease (SD)≥6 months for a clinical benefit rate (CBR) of 40%. Tissue was available for testing in 43 pts and 32 (74%) had a PI3K pathway activating aberration (Table 1).

Response According to PI3K Pathway AberrationPI3K Pathway AberrationN (%)CRPRSD≥6monthsCBRORRAny PI3K Pathway Aberration*32 (74)46444%31%PIK3CA Mutation19 (59)23447%26%p.H1047R12 (38)21350%25%p.E545K6 (19)02150%33%p.G1007R1 (3)010100%100%p.E545A1 (3)0000%0%p.H1047Y1 (3)0000%0%p.K111E1 (3)0000%0%p.E542K1 (3)0000%0%PIK3CA Amplification1 (3)010100%100%PTEN Mutation5 (16)0000%0%PTEN Loss5 (16)02040%40%AKT1 p.E17K Mutation2 (6)0000%0%AKT2 Amplification1 (3)100100%100%PIK3R1 Mutation2 (6)01050%50%NF2 Mutation1 (3)100100%100%No PI3K Pathway Aberration11 (26)00545%0%*Some tumors had &gt;1 aberration detected

PI3K pathway activation was associated with a significant improvement in ORR (31 vs 0%; P=0.043) but not CBR (44 vs 45%; P=1.000) or progression-free survival (median 5.1 vs 2.9 months; P=0.352). A pt with 5 year+ durable CR (on maintenance everolimus) had a mutation in NF2. To emphasize the importance of pt selection, it is notable that 12 pts with non-metaplastic TNBC were also treated with DAT, and only 1 pt had a response (CR/PR=1; SD≥6 months=0), for a CBR that was significantly worse than pts with MpBC (8 vs 40%; P=0.045).

Conclusions: Using MpBC as a surrogate of response, DAT/DAE has significantly better activity in mesenchymal compared to non-selected TNBC. Response is enhanced in pts with PI3K pathway activation. DAT/DAE should be tested in non-metaplastic, mesenchymal TNBC once a diagnostic assay is available.

Citation Format: Basho RK, Gilcrease M, Murthy RK, Helgason T, Booser DJ, Karp DD, Meric-Bernstam F, Wheler JJ, Valero V, Albarracin C, Litton J, Chavez-MacGregor M, Ibrahim NK, Murray JL, Koenig KB, Hong D, Subbiah V, Kurzrock R, Janku F, Moulder S. Targeting the PI3K/AKT/mTOR pathway for the treatment of mesenchymal triple-negative breast cancer (TNBC): Evidence of efficacy and proof of concept from a phase I trial with dose expansion of mTOR inhibition in combination with liposomal doxorubicin and bevacizumab. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-14-02.

Abstract OT1-02-01: Pilot study of prognostic utility of circulating tumor cells (CTCs) assessed by AdnaGen technology and clinical outcome of patients with stage III breast cancer who completed locoregional and systemic treatment

Background: Detection of high number of CTCs (&gt;5) before initiation of first-line therapy in patients with metastatic breast cancer is associated with shorter progression free survival and overall survival. The most widely used method is CellSearch (Veridex, Raritan, NJ). It relies on immunomagnetic capture of CTCs, using antibodies against the epithelial cell adhesion molecule (EpCAM). Although the US Food and Drug Administration approved CellSearch assay for clinical use. In addition to isolation and enumeration, a promising area of research is genomic CTCs characterization which entails phenotyping and molecular expression profiling of CTC subsets consisting of those of epithelial origin (CTC-Epi), others undergoing epithelial to mesenchymal transition (CTC-EMT), or expressing cancer stem cell-like phenotype (CTC-CSC; CD44+ CD24low, ALDH+), respectively. EMT is a molecular process to acquire the traits needed to execute the multiple steps of metastasis. Through the EMT process, epithelial cells lose cell-cell contacts and cell polarity, downregulate epithelial-associated genes, acquire mesenchymal gene expression and undergo major changes in their cytoskeleton. Currently, a CTC detection kit is available to detect CTCs expressing EMT-associated genes by semiquantitative RT-PCR (Adna EMT2/Stem Cell test). EMT will be detected by measuring EMT-inducing transcription factors such as TWIST1, SNAIL1, SLUG, ZEB1 and FOXC2) by RT-PCR

Objectives. Primary objective: To investigate if activated pathways in CTCs are correlated with clinical outcome of patient with stage III breast cancer. Secondary objective: To prospectively determine if assessment of the pathways profiling in CTCs can be used to stratify NED breast cancer patients

Patients Eligibility: Inclusion: histologically confirmed invasive breast cancer (any subtype), clinical stage III, no evidence of distant metastasis by PET-CT or CT scan of chest and abdomen, and body scan, age 18 years or older, pts must be scheduled to start neoadjuvant/adjuvant therapy, ECOG PS 0-2. Pts must sign a written informed consent. Exclusion: distant metastasis, investigational therapy, prior history of other malignancies within the last 2 years, except non-melanoma skin cancer. This study (PA12-0097) was approved by IRB of UT MD Anderson Cancer Center.

Trial Design. This is a pilot, international, multicenter, prospective, blood sample collection from 200 patients with clinical or pathologic stage III breast cancer.

Statistical Analysis: This study is a 7-year study (84 months). Pts will be classified as to the presence [negative (neg) vs. positive (pos)] of CTC and as to the expression of a biomarker (neg vs. pos). The primary endpoint of the study is breast cancer recurrence. Time to recurrence curves for the four breast cancer patient groups (neg/neg, neg/pos, pos/neg, or pos/pos) will be estimated using the Kaplan-Meier method and differences in the recurrence rates will be evaluated by the log-rank test at the end of the study (84 months). The confidence intervals for the quantiles of the recurrence distribution will be based on the sign test as described by Brookmeyer and Crowley.

Citation Format: Alvarez RH, Gao H, Ensor JE, Gomez HL, Ruiz-Garcia EB, Arce C, Sun H, Willey JS, Ueno NT, Valero V, Reuben JM. Pilot study of prognostic utility of circulating tumor cells (CTCs) assessed by AdnaGen technology and clinical outcome of patients with stage III breast cancer who completed locoregional and systemic treatment. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr OT1-02-01.

Abstract P6-03-09: Genetic polymorphism and correlation with treatment induced cardiotoxicity and prognosis in HER2 amplified early breast cancer patients

Introduction: Small studies have indicated a possible correlation between a HER2 gene polymorphism at codon 655 and trastuzumab-associated cardiotoxicity. Association between a synonymous coding variant rs7853758 within the SLC28A3 gene and anthracycline induced cardiotoxicity has also been reported. This study aimed to validate these correlations and assess for any relationship with prognosis.

Methods: Genomic DNA was isolated from 666 patients enrolled in a large trial of adjuvant chemotherapy in HER2 amplified early breast cancer (BCIRG 006). Genotyping was conducted using Sequenom MassARRAY System for HER2 G-&gt;A polymorphism at amino acid codon 655 (rs1136201) and variant rs7853758 (L461L) within the SLC28A3 gene.

Results: Of the 666 patients analyzed, 216 patients were treated with anthracycline based therapy, 226 with trastuzumab based therapy, and 224 with regimens containing both an anthracycline and trastuzumab. Compared with the overall results of the BCIRG006 study (N=3,222), in the subset of patients genotyped in this analysis, a less robust improvement in disease free survival (DFS) was observed for the trastuzumab arms than control arm (HR, 0.821). When stratified for prognostic features, the hazard ratio in favor of trastuzumab was consistent with that of the overall study (HR, 0.674). Samples from 662 patients were successfully genotyped for rs1136201. Of these, 424 (64%) were AA, 30 (4.5%) were GG, 208 (31%) were AG genotype. Samples from 665 patients were successfully genotyped for rs7853758. Of these, 19 (3%) were AA, 475 (71%) were GG, and 171 (26%) were AG genotype. There was no correlation seen between mean left ventricular ejection fraction (LVEF) and HER2 genotype at codon 655 in patients treated with trastuzumab. Of patients tested for the HER2 polymorphism, cardiac dysfunction [defined as &gt; 10% decline in LVEF or clinical congestive heart failure (CHF)] developed in 16% of patients with AA, 17% of patients with GG and 20% of patients with AG. There was also no correlation between mean LVEF and variant rs7853758 in patients treated with anthracyclines. The percentage of patients who developed cardiac dysfunction was 13%, 17% and 21% in AA, GG, and AG genotypes respectively. No correlation between disease free survival and any of the genotypes was seen.

Conclusion: In the largest analysis to date to evaluate for relationship between cardiac toxicity and HER2 polymorphism, we did not find a correlation with rs1136201 HER2 polymorphism and trastuzumab induced cardiac toxicity. Our study also did not show a correlation between variant rs7853758 (L461L) and anthracycline induced cardiotoxicity. Neither polymorphism correlated with prognosis.

Citation Format: Peddi PF, Hurvitz SA, Fasching PA, Wang L, Cunningham J, Weinshilboum RM, Liu D, Quinaux E, Fourmanoir H, Robert NJ, Valero V, Crown J, Falkson C, Brufsky A, Pienkowski T, Eiermann W, Martin M, Bee V, Slamon DJ. Genetic polymorphism and correlation with treatment induced cardiotoxicity and prognosis in HER2 amplified early breast cancer patients. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-03-09.

Abstract P4-14-22: A single-center, open-label phase 1b study of entinostat, and lapatinib alone, and in combination with and trastuzumab in patients with HER2+ metastatic breast cancer after progression on trastuzumab

Background: Our in vitro and in vivo preclinical data showed that entinostat enhances the efficacy of lapatinib in HER2 positive (HER2+) breast cancer cells via FOXO3-mediated Bim1 expression, which resulted in enhanced apoptosis in HER2 targeted therapy (lapatinib and trastuzumab)-resistant breast cancer (IBC and non-IBC) cells [Lee et al.]. Based on these findings, we conducted a phase 1b trial of entinostat to determine the maximal tolerated dose (MTD) in combination with lapatinib alone and in combination with lapatinib and trastuzumab for metastatic HER2+ breast cancer patients (pts), who progressed on trastuzumab.

Method: This was a single-center, open-label phase 1b study to evaluate the dose limiting toxicity (DLT) and determine MTD. 3+3 dose escalation schedule was used for Cohorts 1 and 2. Pts received lapatinib and entinostat (Cohort 1) or entinostat, lapatinib, and trastuzumab (Cohort 2). Initial dose of lapatinib 1250mg in Cohort 1 and 1000mg for Cohort 2 to match standard dose in combination with trastuzumab dose. In Cohort 1, entinostat was given PO on day 1 and 15 every 28 days cycle at dose levels 10 mg (level 0), 12 mg (level 1), or 15 mg (level 2). The dose levels for Cohort 2 were 12 mg (co-level 0) or 15 mg (co-level 1) on day 1 and 15 every 28 days cycle. While lapatinib and entinostat were given 28 days cycle due to entinostat dosing, the dosing of trastuzumab followed approved schedule every 21 days starting at 8mg/kg loading followed by 6mg/kg q 3 wks in Cohort 2 and 3. After the MTD of entinostat in cohort 2 was determined at 12mg, an expansion cohort of 10 pts (cohort 3) was conducted.

Results: Median age was 52 (26-69 yrs). Median number of prior trastuzumab-based regimens was 2 (1-6), 8 pts had lapatinib containing treatment prior to the trial, including 5 pts who had clinical benefit. 16 had ER+ and 13 ER negative, and 9 had IBC. Clinical efficacy and toxicity of treatment is summarized in table 1. Out of 14 pts who had clinical benefit (CR, PR, SD), 6 had IBC. Three pts are still on therapy (1CR, 1PR, 1SD).

Table 1. Clinical Efficacy, Toxicity of combination Receptor StatusResponseGrade 3 toxicityGrade 4 toxicityCohort 1HER2+/ER- (N=8) HER2+/ER+ (N=7)CR (N=1; 8M), SD (N=4;1,2,4M)Lapatinib dose reduction: 3 pts Rash (2) Abdominal pain + dyspnea (1)Entinostat dose reduction: 2pts Neutropenia (1 at 12mg, 1 at 15mg)Cohort 2/3HER2+/ER- (N=8) HER2+/ER+ (N=6)CR (N=2; 3,6M), PR (N=2;4,5M) SD (N=5;1,2,4,6M)Lapatinib dose reduction: 2 pts Diarrhea (N=1 at 12mg N=1 at 10mg) Entinostat dose reduction: 5 pts Neutropenia (N=2 at 12 mg) Leukopenia (N=1 at 12mg) Anemia (N=1 at 12mg)Entinostat dose reduction: 2pts Hypokalemia (N=1 at 12mg) Thrombocytopenia (N=1 at 15mg)CR: complete response, PR: partial response, SD: stable disease, N=number of pts, M=months

Conclusion: MTD was reached at 12mg q 2wkly entinostat, lapatinib 1000 mg daily and trastuzumab 8 mg/kg followed by 6mg/kg q 3 wks. This combination was safe and had promising clinical efficacy in patients with trastuzumab-resistant metastatic HER2+ breast cancer including IBC, warranting further study.

Citation Format: Lim B, Jackson S, Alvarez RH, Ibrahim NK, Willey JS, Murthy RK, Booser DJ, Giordano SH, Barcenas CH, Brewster A, Walters RS, Brown PH, Tripathy D, Valero V, Ueno NT. A single-center, open-label phase 1b study of entinostat, and lapatinib alone, and in combination with and trastuzumab in patients with HER2+ metastatic breast cancer after progression on trastuzumab. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-14-22.

Inflammatory Breast Cancer: A Distinct Clinicopathological Entity Transcending Histological Distinction

Introduction

Although well recognized in breast oncology literature, histologic subtypes have not been previously described in inflammatory breast cancer (IBC). The purpose of this study was to describe lobular subtype in IBC and assess the impact of histology on patient outcomes.

Methods

We performed a retrospective analysis of 659 IBC patients at MD Anderson Cancer Center between January 1984 and December 2009. Patients with Invasive Lobular, Mixed Invasive Ductal and Lobular, or Invasive Ducal Carcinomas (ILC, MIC, IDC, respectively) comprise the subject of this report. Patient characteristics and survival estimates were compared by using chi-square test and Kaplan-Meier method with log-rank statistic. Cox proportional hazards models were fit to determine association of histology with outcomes after adjustment for other characteristics.

Results

A total of 30, 37, and 592 patients were seen to have invasive lobular, mixed, or ductal histology, respectively. Grade 3 tumors were more common in the ductal group (78%) than in the lobular (60%) or mixed (61%) group (P = 0.01). The 3-year overall survival rates were 68%, 64%, and 62% in the lobular, mixed, and ductal groups, respectively (P = 0.68). After adjustment, histology did not have a significant effect on death in the lobular group (HR = 0.70, 95% confidence interval [CI]: 0.26–1.94; P = 0.50) or mixed group (HR = 0.53, 95% CI: 0.25–1.13; P = 0.10) compared with the ductal group.

Conclusion

In this cohort of IBC patients, lobular histology was seen in 4.5% cases. Histology does not appear to have a significant effect on survival outcomes in IBC patients, unlike in patients with non-inflammatory breast cancer (n-IBC), indicating the distinct biological behavior of the IBC phenotype.

Randomized, phase II, placebo-controlled trial of onartuzumab and/or bevacizumab in combination with weekly paclitaxel in patients with metastatic triple-negative breast cancer

BACKGROUND

Increased hepatocyte growth factor/MET signaling is associated with an aggressive phenotype and poor prognosis in triple-negative breast cancer (TNBC). We evaluated the benefit of adding onartuzumab, a monoclonal anti-MET antibody, to paclitaxel with/without bevacizumab in patients with TNBC.

PATIENTS AND METHODS

Women with metastatic TNBC were randomized to receive onartuzumab plus placebo plus weekly paclitaxel (OP; n = 60) or onartuzumab plus bevacizumab plus paclitaxel (OBP; n = 63) or placebo plus bevacizumab plus paclitaxel (BP; n = 62). The primary end point was progression-free survival (PFS); additional end points included overall survival (OS), objective response rate (ORR), and safety. This trial was hypothesis generating and did not have power to detect minimum clinically meaningful differences between treatment arms.

RESULTS

There was no improvement in PFS with the addition of onartuzumab to BP [hazard ratio (HR), 1.08; 95% confidence interval (CI) 0.69-1.70]; the risk of a PFS event was higher with OP than with BP (HR, 1.74; 95% CI 1.13-2.68). Most patients had MET-negative tumors (88%); PAM50 subtype analysis showed basal-like tumors in 68% of samples. ORR was higher in the bevacizumab arms (OBP: 42.2%; 95% CI 28.6-57.1; BP: 54.7%; 95% CI 41.0-68.4) compared with OP (27.5%; 95% CI 15.9-40.6). Median OS was shorter with OBP (HR, 1.36; 95% CI 0.75-2.46) and OP (HR, 1.92; 95% CI 1.03-3.59), than with BP. Peripheral edema was more frequent in the onartuzumab arms (OBP, 51.8%; OP, 58.6%) versus BP (17.7%).

CONCLUSION

This study did not show a clinical benefit of the addition of onartuzumab to paclitaxel with/without bevacizumab in patients with predominantly MET-negative TNBC.

CLINICALTRIALSGOV

NCT01186991.