Citations

Abstract Background: We have previously shown in animal models that combination anti-HER2 therapy leads to complete tumor regression of HER2+ breast cancer (BC). We translated these findings in a neoadjuvant trial of 12 weeks (wks) of L+T (TBCRC006) that demonstrated a meaningful pathologic complete response (pCR) and near pCR (in ER+ tumors) in patients with locally advanced HER2+ BC. In the present trial, we sought to determine whether longer treatment would lead to a higher rate of pCR without the use of chemotherapy by converting near pCR to pCR especially in the ER+ subset. Methods: TBCRC023 (NCT00999804) is a randomized phase II trial combining a Simon Phase 2 design in the experimental arm with a pick-the-winner design, not powered for direct comparison. Women with HER2+ BC measuring 2 cm or larger were eligible and were randomized in a 1:2 ratio to 12 vs. 24 wks of L+T. Letrozole (along with ovarian suppression if premenopausal) was also administered in patients whose tumors were also ER+. Serial tumor biopsies were obtained at baseline, wk 1, wk 12, and at the time of surgery. All evaluable patients were assessed for pCR, defined as no residual invasive carcinoma in the breast. Patients did not undergo surgery, withdrew consent, or received additional neoadjuvant therapy were counted as non-responders. Results: Ninety-seven patients were enrolled (33 in 12-wk arm and 64 in 24-wk arm), of whom 95 were evaluable. Seventy seven percent of patients were white and 18% were black. Twenty percent were of Hispanic ethnicity. Median age was 51 and 55% were postmenopausal. Median tumor size was 5 cm and 65% were ER+. Study treatment was well tolerated with grade 1-2 diarrhea (24% in 12-wk arm, 31% in 24-wk arm) and grade 1-2 acneform rash (12% in 12-wk arm, 19% in 24-wk arm) being the most common toxicities. Grade 3 toxicities were uncommon and were mostly in the 24-wk arm (elevated liver function test: 9%, diarrhea 2%, mucositis 2%), while the 12-wk arm had one grade 3 anemia and the study’s only serious adverse event (acute kidney injury). There were no grade 4 toxicities. The experimental arm completed stage 2 accrual and pCR rate was numerically superior to control, entirely due to better results in ER+ (Table 1), but lower than the expected pCR rate of 36% needed in the planned analysis to conclude in favor of enhanced efficacy with extended therapy. pCR rates were also lower in the control arm than in the previous study. Table 1. pCR rates 12-week arm % (n)24-week arm % (n)ER-positive8.7% (2/23)33.2% (13/39)ER-negative20% (2/10)8.7% (2/23)Overall pCR12.2% (4/33)24.2% (15/62) Conclusions: Treatment with L+T (with endocrine therapy in ER+ tumors) for 24 weeks leads to doubling of the pCR rate in women with HER2+ breast cancer without using cytotoxic chemotherapy. This approach is effective and well tolerated and warrants study as part of a de-escalation strategy that may spare some patients the cost and toxicity of chemotherapy. Tissue obtained on this trial will provide a valuable resource to validate correlative findings from our prior studies and discover new biomarkers to help guide proper patient selection for treatment. Citation Format: Mothaffar F Rimawi, Polly A Niravath, Tao Wang, Brent Rexer, Andres Forero, Antonio C Wolff, Rita Nanda, Anna M Storniolo, Ian Krop, Matthew P Goetz, Julie R Nangia, Sao Jiralerspong, Anne C Pavlick, Carolina Gutierrez, Rachel Schiff, Susan G Hilsenbeck, C Kent Osborne. TBCRC023: A randomized multicenter phase II neoadjuvant trial of lapatinib plus trastuzumab, with endcorine therapy and without chemotherapy, for 12 vs. 24 weeks in patients with HER2 overexpressing breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S6-02.

Abstract Background: We had previously reported after a median followup of 5.3 years that disease free survival (DFS) was improved with either adjuvant weekly paclitaxel (hazard ratio [HR] 0.73, p=0.0006) or every 3 week docetaxel (HR 0.77, p=0.02) compared with every 3 week paclitaxel (N Eng J Med 2008; 358; 1663), and that obesity and black race were independently associated with inferior outcomes in estrogen receptor (ER)-positive disease after a longer followup (Cancer 2012: 118: 5937 & JNCI 2012; 104: 406). We now report updated results after a median followup of 12.1 years. Methods: Eligibility included axillary lymph node positive or high-risk (tumor at least 2 cm) node-negative breast cancer. All patients received 4 cycles of AC (doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2) every 3 weeks, followed by either: (1) paclitaxel 175 mg/m2 every 3 weeks x 4 (P3), (2) paclitaxel 80 mg/m2 weekly x 12 (P1), (3) docetaxel 100 mg/m2 every 3 weeks x 4 (D3), or (4) docetaxel 35 mg/m2 weekly x 12 (D1). Patients with ER-positive breast cancer also received endocrine therapy for at least 5 years, including either tamoxifen and/or an aromatase inhibitor. The primary comparisons included taxane (P vs. D) and schedule (every 3 weeks vs. weekly), and the primary endpoint was DFS, defined as local, regional, and/or distant relapse, second primary breast cancer, or death without recurrence. Results: A total of 4954 eligible patients were accrued between October 1999 and January 2002. At the time of this analysis, 90% of surviving patients were followed for at least 10 years, and there were substantially more DFS events (1639 vs. 1048) and deaths (1283 vs. 686) than the original report. For the primary comparison, there remains no significant difference in DFS by taxane (p=0.33) or schedule (p=0.88), although there was a significant interaction between taxane and schedule (p<0.007). When comparing the standard arm (P3) to the other arms (with a hazard ratio [HR] < 1 favoring the experimental arms using a stratified Cox model), the HRs for DFS were 0.84 (p = 0.011) for arm P1 and 0.79 (p=0.001) for arm D3 arm, and for overall survival (OS) were 0.87 (p=0.09) and 0.86 (p=0.054), respectively. When evaluated by subtypes in exploratory analyses, the P1 arm (but not the D3 arm) was associated with improved DFS (HR 0.69, p=0.01) and OS (HR 0.69, p=0.019) in the 1025 patients with triple negative breast cancer (TNBC), and the D3 arm (but not P1 arm) was associated with improved DFS (HR 0.76, p=0.004) but not OS (HR 0.87, p=0.20) in the 2785 patients with ER-positive, HER2-negative/unknown breast cancer (ERBC). In ERBC but not other subtypes, black race (HR 1.60, p=0.002) and obesity (HR 1.23, p=0.009) were associated with inferior OS, and obesity was associated with a higher recurrence risk between 3-8 years after diagnosis. Conclusions: Improvements in DFS observed at 10 years for the P1 and D3 arms compared with the P3 arm are qualitatively similar but quantitatively less than at 5 years, and the effects on OS are marginal in the overall population. The relative effectiveness of weekly paclitaxel and every 3 week docetaxel may vary by subtype. Citation Format: Joseph A Sparano, Fengmin Zhao, Silvana Martino, Jennifer Ligibel, Thomas Saphner, Antonio C Wolff, George W Sledge Jr, Edith A Perez, William C Wood, Nancy E Davidson. Ten year update of E1199: Phase III study of doxorubicin-cyclophosphamide followed by paclitaxel or docetaxel given every 3 weeks or weekly in patients with axillary node-positive or high-risk node-negative breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr S3-03.

Abstract Background: Although the spectrum of genomic alterations in primary, treatment-naïve breast tumors has been described, the genomic landscape of HER2+ MBC remains underexplored. Furthermore, tumor genomic alterations that arise after progression on anti-HER2 therapy are largely unknown. Methods: We prospectively collected metastatic tumor biopsies from patients (pts) enrolled on TBCRC003 (NCT00470704), a phase II study evaluating the combination of lapatinib (L) and T in pts with HER2+ MBC who had varying degrees of prior T exposure. We performed WES on baseline metastatic biopsies and normal DNA from 57 pts. In 36 pts, we also performed WES on pre-treatment primary tumors. Tumors were analyzed for point mutations, insertions/deletions, and copy number alterations. Results: Total accrual was 116 pts. 87 pts were registered in one of two efficacy cohorts: Cohort 1 included pts w no prior T for MBC. Pts with prior adjuvant T were included if the interval from last T to 1st recurrence > 12 months. Cohort 2 included pts with 1-2 prior lines of T for MBC or recurrence within 12 months of adjuvant T. An additional 29 pts were enrolled in a biomarker cohort (Cohort 3). Per-protocol efficacy analyses for 85 pts deemed evaluable are shown below: Objective Response RateClinical Benefit RateMedian Time to ProgressionCohort 150% (90% CI 33.8-66.2%)57.5% (95% CI 40.9-73.0)7.4 monthsCohort 222.2% (90% CI 11.2-37.1%)42.2% (95% CI 27.7-57.8)5.3 months As we previously reported (Wagle et al, ASCO 2014), across 57 metastatic tumors, significant recurrently mutated genes were TP53 (n=30; 53%) and PIK3CA (n=19; 33%). The frequency of mutant TP53 and PIK3CA was not significantly different from 119 primary, treatment-naïve HER2+ tumors sequenced in the TCGA study (50%, p=0.8 and 27%, p=0.5, respectively). Recurrent copy number alterations were also similar to TCGA data. Comparing the 38 pts who received any prior T with the 19 pts who did not, there was no significant difference in the incidence of mutant TP53 (53% vs 53%, p=1.0) and PIK3CA (37% vs 26%, p=0.6). We identified mutations in the HER2 kinase domain in 4/38 pts who received prior T (11%), as compared to 0/19 T-naïve pts. HER2 kinase domain mutations have been identified in ∼2% of HER2-negative cancers but <1% of primary HER2+ cancers. 3 of the mutations were L755S, which has been shown to be resistant to L and sensitive to irreversible HER2 inhibitors. The 4th mutation was D742N, a novel kinase domain mutation. None of the 4 pts with HER2 kinase domain mutations had an objective response, though 1 pt had stable disease for 29 weeks. An analysis comparing paired archival primary tumors and baseline metastatic biopsies from 36 pts to identify genomic alterations acquired or enriched in the metastatic tumors will be presented. Conclusions: We present an analysis of the genomic landscape of HER2+ MBC, including comparisons between matched primary tumors and metastatic biopsies. Somatic HER2 kinase mutations in pts with HER2+ MBC treated with prior T suggests that these mutations may be involved in resistance to T, and may predict poor response to additional anti-HER2 therapy with combined L and T. Novel therapeutic approaches may be required for these pts. Citation Format: Nikhil Wagle, Nancy U Lin, Andrea L Richardson, Ignaty Leshchiner, Ingrid A Mayer, Andres Forero-Torres, Timothy J Hobday, Elizabeth C Dees, Rita Nanda, Mothaffar F Rimawi, Hao Guo, William T Barry, Ron Bose, Wei Shen, Antonio C Wolff, Stacey B Gabriel, Levi A Garraway, Eric P Winer, Ian E Krop. Whole exome sequencing (WES) of HER2+ metastatic breast cancer (MBC) from patients with or without prior trastuzumab (T): A correlative analysis of TBCRC003 [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr PD3-5.

Abstract Background: CTCs are associated with clinical outcomes in metastatic breast cancer irrespective of ER/PR/HER2 status. Some data support the prognostic relevance of serial CTC enumeration relative to adjuvant chemotherapy in early stage breast cancer. However, data from a large scale study focused on HER2 directed therapy for HER2+ disease have been lacking. We therefore sought to prospectively evaluate the effect of trastuzumab +/- lapatinib on CTCs and assess the prognostic/predictive value of CTC monitoring in HER2+ early stage breast cancer patients (pts). Methods: The Adjuvant Lapatinib and/or Trastuzumab Treatment Optimisation (ALTTO; NCT00490139) Trial is an international, randomized, open-label phase III study of two targeted agents for HER2+ breast cancer. From June 2007 to July 2011, 8381 pts were randomised from 946 sites in 44 countries to 1 of 4 arms with sequential or concurrent chemotherapy: (i) 52 wks of trastuzumab (T); (ii) 52 wks of oral lapatinib (L); (iii) 12 or 18 wks of T followed by a washout and then 34 or 38 wks of L; or (iv) 52 wks of L+T. 540 (6%) pts provided optional informed consent and up to 30 mL peripheral blood suitable for CTC analyses at baseline with additional collections at 13 or 19 wks, 52 wks, 18 mos, 24 mos, and recurrence. CTC analyses are being conducted in three laboratories (Mayo Clinic Rochester, n=431; Institut Jules Bordet and University of Munich, n=109). 2-3 x 10 mL CellSave™ samples are pooled and processed at each time point for CTC enumeration and HER2 expression using the immunomagnetic/immunofluorescence assay (CellSearch™). A round-robin concordance project was done between Mayo Clinic Rochester and Institut Jules Bordet before embarking on the primary correlative work. Results: At baseline, 20% pts had detectable (i.e., ≥1) EpCAM+/CK+/DAPI+/CD45- CTCs, and 16% pts had detectable EpCAM+/CK+/DAPI+/CD45-/HER2+ CTCs. Correlative analyses with clinical outcome are ongoing with plans for completion by Fall 2014. Conclusions: CTCs were detected in 20% of pts with HER2+ early stage breast cancer. This is similar to the frequency of detection in mixed early stage breast cancer populations relative to ER/PR and HER2 status. Concordance of enumeration and HER2 assessments between the two experienced laboratories, and correlation between disease free survival and CTC findings (from serial samples collected at baseline, during the course of HER2 directed therapy, and at set intervals of follow-up) will be reported. Citation Format: Minetta C Liu, Brigitte Rack, Amylou C Dueck, David W Hillman, Michael B Campion, Monica M Reinholz, Kevin C Halling, Christos Sotiriou, Françoise Rothé, Marion Maetens, Ghizlane Rouas, Wolfgang Janni, Antonio C Wolff, Lyndsay N Harris, Julie R Gralow, Kathleen I Pritchard, Susan Ellard, Nguyet A Le-Lindqwister, Frances Boyle, Evandro De Azambuja, Martine J Piccart-Gebhart, Michail Ignatiadis, Edith A Perez. Circulating tumor cell (CTC) enumeration and HER2 assessment as predictors of breast cancer outcomes in the ALTTO (BIG 2-06, Alliance N063D) Trial [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-01-01.

Abstract Purpose: Tigatuzumab (TIG), an agonistic anti-DR5 antibody, triggers apoptosis in DR5+ human tumor cells without crosslinking. TIG has strong in vitro/in vivo activity against basal-like breast cancer cells enhanced by chemotherapy agents. This study evaluates activity of TIG and chemotherapy in patients with metastatic triple-negative breast cancer (TNBC). Experimental Design: Randomized 2:1 phase II trial of albumin-bound paclitaxel (nab-PAC) ± TIG in patients with TNBC stratified by prior chemotherapy. Patients received nab-PAC weekly × 3 ± TIG every other week, every 28 days. Primary objective was within-arm objective response rate (ORR). Secondary objectives were safety, progression-free survival (PFS), clinical benefit, and TIG immunogenicity. Metastatic research biopsies were required. Results: Among 64 patients (60 treated; TIG/nab-PAC n = 39 and nab-PAC n = 21), there were 3 complete remissions (CR), 8 partial remissions (PR; 1 almost CR), 11 stable diseases (SD), and 17 progressive diseases (PD) in the TIG/nab-PAC arm (ORR, 28%), and no CRs, 8 PRs, 4 SDs, and 9 PDs in the nab-PAC arm (ORR, 38%). There was a numerical increase in CRs and several patients had prolonged PFS (1,025+, 781, 672, 460, 334) in the TIG/nab-PAC arm. Grade 3 toxicities were 28% and 29%, respectively, with no grade 4–5. Exploratory analysis suggests an association of ROCK1 gene pathway activation with efficacy in the TIG/nab-PAC arm. Conclusions: ORR and PFS were similar in both. Preclinical activity of TIG in basal-like breast cancer and prolonged PFS in few patients in the combination arm support further investigation of anti-DR5 agents. ROCK pathway activation merits further evaluation. Clin Cancer Res; 21(12); 2722–9. ©2015 AACR. See related article by Paoletti et al., p. 2771

Abstract Background: 1/3 of women with metastatic HER2+ breast cancer will develop central nervous system (CNS) metastases yet evidence-based treatments for women with progressive CNS disease are limited. Neratinib is an irreversible inhibitor of erbB1, HER2, and erbB4 which has promising activity in HER2+ breast cancer. Preclinical evidence suggests it may cross the blood brain barrier. Trial Design: This is a multicenter, phase II, open-label study of neratinib for patients with HER2+ breast cancer and brain metastases. Neratinib is administered at 240 mg orally daily during a 28 day cycle. Two cohorts will be enrolled: Cohort 1 will enroll 40 patients with progressive CNS disease; cohort 2 will enroll ≤5 patients who are candidates for surgical excision of intracranial disease. Surgical candidates receive neratinib 7–21 days preoperatively and resume postoperatively. All patients are re-staged every 2 cycles. Those who develop non-CNS progression have an option to extend therapy with trastuzumab+neratinib. Circulating tumor cells (CTC) are collected at baseline and progression; neurocognitive testing, HADS and EORTC QLQ30/BN20 measures are administered at baseline, cycle 2, cycle 3, and progression (cohort 1). Intracranial tumor, cerebrospinal fluid (CSF), and plasma are collected at surgery (cohort 2). Specific Aims: The primary endpoint is CNS objective response rate (ORR) by composite criteria. Additional endpoints include: non-CNS ORR, progression-free survival, overall survival (OS), site of 1st progression, and toxicity. Correlative and exploratory endpoints include association of CTC count and OS and longitudinal neurocognitive function and quality of life. In an exploratory analysis (cohort 2), we will quantify neratinib concentrations in CSF, intracranial tissue, and plasma and examine associations with response. Eligibility: Patients must have confirmed HER2+ metastatic disease with ≥1 parenchymal brain lesion measuring ≥10 mm that is new or progressed after completing ≥1 line of standard CNS-directed treatment (cohort 1) or CNS disease that is amenable for surgery, including those without prior CNS treatments (cohort 2). Additional eligibility criteria (cohorts 1,2) include: adequate performance status and end organ/marrow function, and ejection fraction ≥50%. Any number of prior lines of therapy is allowed, including prior lapatinib. Statistical Methods: Cohort 1 has a 2-stage design with up to 40 patients. CNS ORR is defined as ≥50% reduction in sum volume of CNS target lesions, without evidence of new lesions, progression of non-target CNS lesions, non-CNS disease progression, worsening neurological symptoms, or increase in corticosteroids. CNS lesion measurements are performed centrally by the Harvard Tumor Imaging Metrics Core. If 1/18 patients have a CNS response in the 1st stage, another 22 patients will enroll. With this design, if ≥5 of 40 patients achieve a CNS response, the drug will be deemed worthy of future study. This 2-stage design has 92% power to distinguish between a true CNS ORR of 20% and a null of 6% (one-sided type I error rate=9%). Accrual: Accrual has begun. Target=45 (cohort 1=40, cohort 2=5) Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr OT1-1-11.

Abstract Background: Retrospective studies suggest that primary breast surgery is associated with improved overall survival (OS) in Stage IV breast cancer. TBCRC 013 is a multi-center prospective registry study evaluating the role of surgery for the primary tumor in Stage IV disease. Methods: From 7/09 - 4/12, 128 eligible pts from 14 sites were enrolled in two cohorts (A: Stage IV with intact primary tumor (n = 112); B: metastases (mets) within 3 months of primary surgery (n = 16)). Baseline patient and tumor characteristics, and surgery of the primary were correlated with 2yr overall survival (OS) using log rank, Kaplan Meier and Cox regression for all patients. Comparisons were also made between cohorts A and B and within cohort A stratified by response to systemic therapy. Responders included those with any response (partial,complete) or stable disease at distant sites. Results: Median pt age was 52yrs(21-79) and median primary tumor size 3.2cm(0.7-15). Phenotypes were ER+ 106 (83%), HER2neg 91(71%), and triple neg 10(8%). 60(47%) had bone-only mets. The only significant baseline difference between cohorts A and B was the presence of palpable nodes (A:62% vs B:0%, p<0.001). There were no differences in age, tumor size, ECOG scores, ER or HER2 status, number or sites of mets between cohorts A and B. At a median follow-up of 25 mo (95%CI, 23-31), 2yr OS for all pts is 86% (80-92) and is superior in cohort B as compared to A, (100% vs 84%, p = 0.03). On multivariate analysis (MVA) including all pts, only surgery, ER and HER2 positivity were associated with improved OS (table). Among 112 pts with an intact primary (Arm A), 17(15%) were non-responsive (NR) to systemic therapy, 3(18%) of whom required palliative surgery at a median time of 10.4mos. 2yr OS among NR was 33% (15-69) as compared to 94% (88-99) in Arm A responders (R) (p<0.001). ER positivity was the only baseline difference between NR (65%) and R (88%) within Arm A (p = 0.02). Among 94(85%) Arm A responders, 39(41%) had elective surgery (median 8.4 mos, 95%CI:6.9-10.3) and only 1 of the remaining 47(2%) required palliation. When limited to Arm A responders, elective surgery was not associated with improved 2yr OS (surgery vs not: 94% vs 92%, p = 0.5). Median time to progression following elective surgery was 12 mos (95%CI,8-19mos). When cohort B (n = 16) and cohort A surgery groups (n = 39) are combined, surgery of the primary tumor is associated with improved 2yr OS (96% vs 74%, p = 0.002). Conclusions: In this prospective registry study, patients diagnosed with mets within 3 months of primary breast surgery have an improved 2yr OS. When all pts having surgery (A + B) are examined, surgery is associated with improved OS on MVA, but when limited to Arm A responders, elective surgery does not improve OS. Given that the number of Arm A responders is small, results from the prospective randomized trial will be needed to address this question. These data also demonstrate that the need for surgical palliation of the primary tumor is uncommon in the modern era. Multivariate Analysis for OSN = 128HR Death (95%CI)pvalueSurgery0.28 (0.10-0.74)0.01ER positivity0.28 (0.10-0.72)0.01HER2 positivity0.21 (0.06-0.74)0.01MVA included: age, tumor size, ECOG, ER, PR, HER2, met sites, and surgery Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-18-09.

Abstract Background- The ability to consistently detect cell-free tumor-specific DNA in peripheral blood of patients with metastatic breast cancer provides the opportunity to detect changes in tumor burden and to monitor response to treatment. Studies of cell-free DNA in the peripheral blood of breast cancer patients suggest that methylated DNA markers in serum or plasma could be used for detection of advanced disease, monitoring of therapeutic response, and for early detection of disease recurrence. Methods- A genome-wide serum DNA methylome array (Illumina HumanMethylation27 BeadChip) analysis was conducted on cell-free circulating DNA in serum from women with stage IV recurrent breast cancer, and 232 key CpG loci were identified. Methylation for this panel of 10 gene loci was evaluated using our newly developed cMethDNA assay to detect miniscule amounts of methylated DNA in Training and Test sets of sera from a total of 112 women (n = 55 normal, n = 57 metastatic breast cancer). The clinical sensitivity and specificity of the assay, along with technical reproducibility, was determined. To evaluate the concordance of DNA methylation patterns, the 10 gene panel was tested on 22 DNA sets of primary tumor, metastases and serum from the same patient. Finally, the ability of cMethDNA to monitor response to therapy was evaluated in 28 patients with metastatic disease. Results- A normal laboratory threshold of 7 cumulative methylation units was set and assay parameters were locked, based on Receiver Operating Characteristic (ROC) analyses of DNA from 300 ul of patient sera in the Training set (normal, n = 28; cancer, n = 24; 92% sensitivity, 96% specificity, and AUC = 0.950). Evaluation of the Test set of patient sera (normal, n = 27; cancer n = 33) resulted in detection of metastatic breast cancer with 91% sensitivity, 100% specificity, and AUC = 0.994 (0.984-1.005, p<0.0001). Reproducibility of the cMethDNA assay increased with copy number; with the highest variation at 50 copies (CV = 29.1%) and the lowest at 3,200 copies (CV = 2.5%) of methylated DNA. The test was shown to be operator independent (ICC = 0.99). Evaluation of concordance between primary and disseminated tumor methylation showed that the methylation pattern from any given individual is highly conserved between serum, primary tissue and their metastases, and poorly conserved between different individuals. cMethDNA analysis of 28 patients before and after initiation of therapy showed a decrease in cumulative methylation in women with stable/responsive disease and a correlation with disease progression free survival (p<0.0001). Conclusion- Together, our data suggest that the cMethDNA test 1) can detect tumor DNA shed into blood, 2) reflect the methylation alterations typical of the primary tumor and its metastatic lesions, and 3) reflect response to treatment after chemotherapy. Next, we will test the clinical utility of cMethDNA in independent clinical trial sample sets where it's complementary and independent roles will be examined against CA15.3 and CTC assays. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-06-01.

Abstract Background: Circulating Tumor cells (CTCs) are prognostic at baseline and first follow-up in patients with metastatic breast cancer (MBC). Using the most commonly used assay (CellSearch®), we have previously reported the ability to detect apoptotic vs. non-apoptotic CTCs in patients with MBC. However, there has been concern regarding the performance of the CellSearch® assay in patients with triple negative (TN) MBC. We hypothesized that CellSearch® is an effective assay in patients with TN MBC, and that CTC-apoptosis might further separate prognosis. Therefore, we studied CTCs in patients with TN MBC who participated in a prospective randomized phase II trial testing for activity of tigatuzumab (TIG) in combination with nanoparticle albumin-bound paclitaxel (nab-PAC) conducted by the Translational Breast Cancer Research Consortium (overall results reported by Forero A., et al, ASCO 2013). Methods: Whole blood (WB) was drawn into a CellSave tube at baseline, day 15, and day 29 and CTC counts were determined using the CXC CellSearch® kit. Apoptosis was characterized by staining with a monoclonal antibody that detects a neo-epitope on fragmented cytokeratin (M-30) and independently by visual inspection (nucleic condensation and/or fragmentation, as well as granular cytokeratin). Association between levels of CTCs and CTC-apoptosis with the overall response rate (ORR) and progression free survival (PFS) at baseline, day 15, and day 29 was assessed using logistic regression, Kaplan Meier curves, and Cox proportional hazards modeling. Results: Of the 60 patients entered into the trial, 52 were evaluable for CTCs. Of these, 19/52 (36.5%), 14/52 (26.9%), and 13/49 (26.5%) had elevated CTCs (≥5CTC/7.5 ml WB) at baseline, day 15, and day 29, respectively. Patients with elevated CTCs at each time point had worse PFS than patients with low or no CTCs. Hazard rates (HR) at baseline, day 15, and day 29 were 2.38 (95% CI: 1.27-4.45, p = 0.007), 2.87 (95% CI: 1.46-5.66, p = 0.002), and 3.40 (95% CI: 1.68-6.89, p = 0.001), respectively. The odds of overall response for those who had elevated CTCs compared to those who did not at baseline, day 15, and day 29, were 0.25 (95% CI: 0.073-0.81, p = 0.024), 0.18 (95% CI: 0.04-0.67, p = 0.014), and 0.06 (95% CI: 0.01-0.28, p = 0.001), respectively. There was no apparent prognostic effect comparing the degree of CTC-apoptosis vs. non-apoptosis. Conclusions: Similar to observations in other intrinsic subgroups, CTCs were detected in a large fraction of TN MBC patients at baseline using CellSearch® assay, and reductions in CTC levels reflected response. In these homogenously prospectively enrolled TN MBC patients, regardless of treatment, CTCs are prognostic at baseline, day 15, and day 29. It does not appear that analysis of CTC-apoptosis is prognostic. Supported by Susan G. Komen for the Cure, Veridex, LLC, Fashion Footwear Charitable Foundation of New York/QVC Presents Shoes on Sale™ (DFH), Associazione Sandro Pitigliani and by a studentship from FIRC (CP), Triple Negative Breast Cancer Foundation, The AVON Foundation, and The Breast Cancer Research Foundation. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-04-01.