Jeter, S. C.

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: Epigenetic alterations in the genome, including abnormal DNA methylation and histone hypoacetylation, initiate and promote cancerous changes via several mechanisms, including inactivation of tumor suppressor genes. Preclinical investigations in breast cancer suggest that use of epigenetic modifiers results in re-expression of aberrantly silenced genes and proteins that represent important therapeutic targets (e.g. estrogen receptor alpha, ER). Combination therapy with a DNA methyltransferase inhibitor (DNMTI) and a histone deacetylase inhibitor (HDACI) has yielded superior ER reexpression and greater restoration of tamoxifen responsiveness than with HDACI alone. We hypothesize that clinically tolerable doses of the DNMTI 5-azacitidine (5-AZA) and the HDACI entinostat may not only effect changes in DNA methylation and gene expression, but also yield objective disease responses in women with advanced breast cancer. Trial design: This multicenter phase II study (NCT01349959) is enrolling patients with advanced human epidermal growth factor receptor 2 (HER2)-negative breast cancer with triple negative (ER/progesterone receptor [PR]/HER2−negative, Cohort A) or hormone-resistant (Cohort B) disease. Patients will receive 5-AZA 40 mg/m2 subcutaneously days 1–5 and 8–10 and entinostat 7 mg orally days 3 and 10 every 28 days. Because of the potential for re-expression of the ER with epigenetic agents, patients will be offered continuation of 5-AZA and entinostat at progression with the addition of hormonal therapy (investigator discretion). Mandatory tumor biopsies will be performed at baseline and after 8 weeks of therapy to evaluate correlative biomarkers. Eligibility Criteria: Eligible patients must be ≥ 18 years, have measurable locally advanced/metastatic triple-negative (at least one prior chemotherapy received adjuvant/metastatic setting) or hormone-resistant (must have received two prior hormonal agents and one prior chemotherapy) disease, adequate organ function and ECOG PS ≤ 2. Specific Aims: 1. Objective response rate (ORR) by RECIST 1.1 criteria. 2. Safety and tolerability 3. Progression-free survival, overall survival and clinical benefit rate. 4. Safety and toxicity data, feasibility and response rate where hormonal therapy is added to the combination under investigation at the time of progressive disease. 5. Pharmacokinetics, cytidine deaminase, changes from baseline of candidate gene methylation and expression in circulating deoxyribonucleic acid (DNA) and malignant tissue. Statistical Methods: Using a two-stage three-outcome design to assess the efficacy of the combination, a maximum of 30 patients (requiring 27 evaluable) will be accrued to each cohort unless undue toxicity is encountered for a maximum sample size of 60 patients. The study design tests the null hypothesis that the ORR is at most 5% against the alternative hypothesis that it is at least 20% with a type I error of 4% and power of 90%. Present and Targeted Accrual: This study has just opened to patient enrollment. We anticipate a rapid accrual of 60 patients within 1 year.br](Funding from Stand Up to Cancer and CTEP). Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT3-01-06.