Seven-Year Follow-Up Analysis of Adjuvant Paclitaxel and Trastuzumab Trial for Node-Negative, Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer

PURPOSE

The Adjuvant Paclitaxel and Trastuzumab trial was designed to address treatment of patients with small human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The primary analysis of the Adjuvant Paclitaxel and Trastuzumab trial demonstrated a 3-year disease-free survival (DFS) of 98.7%. In this planned secondary analysis, we report longer-term outcomes and exploratory results to characterize the biology of small HER2-positive tumors and genetic factors that may predispose to paclitaxel-induced peripheral neuropathy (TIPN).

PATIENTS AND METHODS

In this phase II study, patients with HER2-positive breast cancer with tumors 3 cm or smaller and negative nodes received paclitaxel (80 mg/m²) with trastuzumab for 12 weeks, followed by trastuzumab for 9 months. The primary end point was DFS. Recurrence-free interval (RFI), breast cancer-specific survival, and overall survival (OS) were also analyzed. In an exploratory analysis, intrinsic subtyping by PAM50 (Prosigna) and calculation of the risk of recurrence score were performed on the nCounter analysis system on archival tissue. Genotyping was performed to investigate TIPN.

RESULTS

A total of 410 patients were enrolled from October 2007 to September 2010. After a median follow-up of 6.5 years, there were 23 DFS events. The 7-year DFS was 93% (95% CI, 90.4 to 96.2) with four (1.0%) distant recurrences, 7-year OS was 95% (95% CI, 92.4 to 97.7), and 7-year RFI was 97.5% (95% CI, 95.9 to 99.1). PAM50 analyses (n = 278) showed that most tumors were HER2-enriched (66%), followed by luminal B (14%), luminal A (13%), and basal-like (8%). Genotyping (n = 230) identified one single-nucleotide polymorphism, rs3012437, associated with an increased risk of TIPN in patients with grade 2 or greater TIPN (10.4%).

CONCLUSION

With longer follow-up, adjuvant paclitaxel and trastuzumab is associated with excellent long-term outcomes. Distribution of PAM50 intrinsic subtypes in small HER2-positive tumors is similar to that previously reported for larger tumors.

The immune profile of small HER2-positive breast cancers: a secondary analysis from the APT trial

BACKGROUND

Previous data suggest that the immune microenvironment plays a critical role in human epidermal growth factor receptor 2 (HER2) -positive breast cancer; however, there is little known about the immune profiles of small HER2-positive tumors. In this study, we aimed to characterize the immune microenvironment of small HER2-positive breast cancers included in the Adjuvant paclitaxel and trastuzumab for node-negative, HER2-positive breast cancer (APT) trial and to correlate the immune markers with pathological and molecular tumor characteristics.

PATIENTS AND METHODS

The APT trial was a multicenter, single-arm, phase II study of paclitaxel and trastuzumab in patients with node-negative HER2-positive breast cancer. The study included 406 patients with HER2-positive, node-negative breast cancer, measuring up to 3 cm. Exploratory analysis of tumor infiltrating lymphocytes (TIL), programmed death-ligand 1 (PD-L1) expression (by immunohistochemistry), and immune gene signatures using data generated by nCounter PanCancer Pathways Panel (NanoString Technologies, Seattle, WA), and their association with pathological and molecular characteristics was carried out.

RESULTS

Of the 406 patients, 328 (81%) had at least one immune assay carried out: 284 cases were evaluated for TIL, 266 for PD-L1, and 213 for immune gene signatures. High TIL (≥60%) were seen with greater frequency in hormone-receptor (HR) negative, histological grades 2 and 3, as well in HER2-enriched and basal-like tumors. Lower stromal PD-L1 (≤1%) expression was seen with greater frequency in HR-positive, histological grade 1, and in luminal tumors. Both TIL and stromal PD-L1 were positively correlated with 10 immune cell signatures, including Th1 and B cell signatures. Luminal B tumors were negatively correlated with those signatures. Significant correlation was seen among these immune markers; however, the magnitude of correlation did not indicate a monotonic relationship between them.

CONCLUSION

Immune profiles of small HER2-positive breast cancers differ according to HR status, histological grade, and molecular subtype. Further work is needed to explore the implication of these findings on disease outcome.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT00542451.

Overall survival and updated progression-free survival outcomes in a randomized phase II study of combination cediranib and olaparib versus olaparib in relapsed platinum-sensitive ovarian cancer

BACKGROUND

Olaparib is a poly(ADP-ribose) polymerase inhibitor and cediranib is an oral anti-angiogenic. In the primary analysis of this phase II study, combination cediranib/olaparib improved progression-free survival (PFS) compared with olaparib alone in relapsed platinum-sensitive ovarian cancer. This updated analysis was conducted to characterize overall survival (OS) and update PFS outcomes.

PATIENTS AND METHODS

Ninety patients were enrolled to this randomized, open-label, phase II study between October 2011 and June 2013 across nine United States-based academic centers. Data cut-off was 21 December 2016, with a median follow-up of 46 months. Participants had relapsed platinum-sensitive ovarian cancer of high-grade serous or endometrioid histology or had a deleterious germline BRCA1/2 mutation (gBRCAm). Participants were randomized to receive olaparib capsules 400 mg twice daily or cediranib 30 mg daily and olaparib capsules 200 mg twice daily until disease progression.

RESULTS

In this updated analysis, median PFS remained significantly longer with cediranib/olaparib compared with olaparib alone (16.5 versus 8.2 months, hazard ratio 0.50; P = 0.007). Subset analyses within stratum defined by BRCA status demonstrated statistically significant improvement in PFS (23.7 versus 5.7 months, P = 0.002) and OS (37.8 versus 23.0 months, P = 0.047) in gBRCA wild-type/unknown patients, although OS was not statistically different in the overall study population (44.2 versus 33.3 months, hazard ratio 0.64; P = 0.11). PFS and OS appeared similar between the two arms in gBRCAm patients. The most common CTCAE grade 3/4 adverse events with cediranib/olaparib remained fatigue, diarrhea, and hypertension.

CONCLUSIONS

Combination cediranib/olaparib significantly extends PFS compared with olaparib alone in relapsed platinum-sensitive ovarian cancer. Subset analyses suggest this margin of benefit is driven by PFS prolongation in patients without gBRCAm. OS was also significantly increased by the cediranib/olaparib combination in this subset of patients. Additional studies of this combination are ongoing and should incorporate analyses based upon BRCA status.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier NCT0111648.

Olaparib and α-specific PI3K inhibitor alpelisib for patients with epithelial ovarian cancer: a dose-escalation and dose-expansion phase 1b trial

BACKGROUND

Based on preclinical work, we found that combination of poly (ADP-ribose) polymerase (PARP) inhibitors with drugs that inhibit the homologous recombination repair (HRR) pathway (such as PI3K inhibitors) might sensitise HRR-proficient epithelial ovarian cancers to PARP inhibitors. We aimed to assess the safety and identify the recommended phase 2 dose of the PARP inhibitor olaparib in combination with the PI3K inhibitor alpelisib in patients with epithelial ovarian cancer and in patients with breast cancer.

METHODS

In this multicentre, open-label, phase 1b trial following a 3 + 3 dose-escalation design, we recruited patients aged 18 years or older with the following key eligibility criteria: confirmed diagnosis of either recurrent ovarian, fallopian tube, or primary peritoneal cancer of high-grade serous histology; confirmed diagnosis of either recurrent ovarian, fallopian tube, or primary peritoneal cancer of any histology with known germline BRCA mutations; confirmed diagnosis of recurrent breast cancer of triple-negative histology; or confirmed diagnosis of recurrent breast cancer of any histology with known germline BRCA mutations. Additional patients with epithelial ovarian cancer were enrolled in a dose-expansion cohort. Four dose levels were planned: the starting dose level of alpelisib 250 mg once a day plus olaparib 100 mg twice a day (dose level 0); alpelisib 250 mg once a day plus olaparib 200 mg twice a day (dose level 1); alpelisib 300 mg once a day plus olaparib 200 mg twice a day (dose level 2); and alpelisib 200 mg once a day plus olaparib 200 mg twice a day (dose level 3). Both drugs were administered orally, in tablet formulation. The primary objective was to identify the maximum tolerated dose and the recommended phase 2 dose of the combination of alpelisib and olaparib for patients with epithelial ovarian cancer and patients with breast cancer. Analyses included all patients who received at least one dose of the study drugs. The trial is active, but closed to enrolment; follow-up for patients who completed treatment is ongoing. This trial is registered with ClinicalTrials.gov, number NCT01623349.

FINDINGS

Between Oct 3, 2014, and Dec 21, 2016, we enrolled 34 patients (28 in the dose-escalation cohort and six in the dose-expansion cohort); two in the dose-escalation cohort were ineligible at the day of scheduled study initiation. Maximum tolerated dose and recommended phase 2 dose were identified as alpelisib 200 mg once a day plus olaparib 200 mg twice a day (dose level 3). Considering all dose levels, the most common treatment-related grade 3-4 adverse events were hyperglycaemia (five [16%] of 32 patients), nausea (three [9%]), and increased alanine aminotransferase concentrations (three [9%]). No treatment-related deaths occurred. Dose-limiting toxic effects included hyperglycaemia and fever with decreased neutrophil count. Of the 28 patients with epithelial ovarian cancer, ten (36%) achieved a partial response and 14 (50%) had stable disease according to Response Evaluation Criteria in Solid Tumors 1.1.

INTERPRETATION

Combining alpelisib and olaparib is feasible with no unexpected toxic effects. The observed activity provides preliminary clinical evidence of synergism between olaparib and alpelisib, particularly in epithelial ovarian cancer, and warrants further investigation.

FUNDING

Ovarian Cancer Dream Team (Stand Up To Cancer, Ovarian Cancer Research Alliance, National Ovarian Cancer Coalition), Breast Cancer Research Foundation, Novartis.

Mixed Invasive Ductal and Lobular Carcinoma of the Breast: Prognosis and the Importance of Histologic Grade

BACKGROUND

The diagnosis of mixed invasive ductal and lobular carcinoma (IDC-L) in clinical practice is often associated with uncertainty related to its prognosis and response to systemic therapies. With the increasing recognition of invasive lobular carcinoma (ILC) as a distinct disease subtype, questions surrounding IDC-L become even more relevant. In this study, we took advantage of a detailed clinical database to compare IDC-L and ILC regarding clinicopathologic and treatment characteristics, prognostic power of histologic grade, and survival outcomes.

MATERIALS AND METHODS

In this retrospective cohort study, we identified 811 patients diagnosed with early-stage breast cancer with IDC-L or ILC. Descriptive statistics were performed to compare baseline clinicopathologic characteristics and treatments. Survival rates were subsequently analyzed using the Kaplan-Meier method and compared using the Cox proportional hazards model.

RESULTS

Patients with ILC had more commonly multifocal disease, low to intermediate histologic grade, and HER2-negative disease. Histologic grade was prognostic for patients with IDC-L but had no significant discriminatory power in patients with ILC. Among postmenopausal women, those with IDC-L had significantly better outcomes when compared with those with ILC: disease-free survival (DFS) and overall survival (OS; adjusted hazard ratio [HR], 0.54; 95% confidence interval [CI] 0.31-0.95). Finally, postmenopausal women treated with an aromatase inhibitor had more favorable DFS and OS than those treated with tamoxifen only (OS adjusted HR, 0.50; 95% CI, 0.29-0.87), which was similar for both histologic types (p = .212).

CONCLUSION

IDC-L tumors have a better prognosis than ILC tumors, particularly among postmenopausal women. Histologic grade is an important prognostic factor in IDC-L but not in ILC.

IMPLICATIONS FOR PRACTICE

This study compared mixed invasive ductal and lobular carcinoma (IDC-L) with invasive lobular carcinomas (ILCs) to assess the overall prognosis, the prognostic role of histologic grade, and response to systemic therapy. It was found that patients with IDC-L tumors have a better prognosis than ILC, particularly among postmenopausal women, which may impact follow-up strategies. Moreover, although histologic grade failed to stratify the risk of ILC, it showed an important prognostic power in IDC-L, thus highlighting its clinical utility to guide treatment decisions of IDC-L. Finally, the disease-free survival advantage of adjuvant aromatase inhibitors over tamoxifen in ILC was consistent in IDC-L.

Unraveling the clinicopathological features driving the emergence of ESR1 mutations in metastatic breast cancer

ESR1 mutations were recently found to be an important mechanism of endocrine resistance in ER-positive (ER + ) metastatic breast cancer. To determine the clinicopathological features driving the emergence of the ESR1 mutations we studied plasma cfDNA and detailed clinical data collected from patients with metastatic breast cancer. Droplet Digital PCR was performed for the detection of the most common ESR1 mutations and PIK3CA mutations. Among the patients with ER + /HER2- disease, ESR1 mutations were detected in 30% of the patients. There were no associations between the pathological features of the primary disease or time to distant recurrence and the emergence of ESR1 mutations in metastatic disease. The prevalence of the ESR1 mutations was significantly associated with prior treatment with an aromatase inhibitor in the adjuvant or metastatic setting. The prevalence of the ESR1 mutations was also positively associated with prior fulvestrant treatment. Conversely, the prevalence of ESR1 mutations was lower after treatment with a CDK4/6 inhibitor. There were no significant associations between specific systemic treatments and the prevalence of PIK3CA mutations. These results support the evolution of the ESR1 mutations under the selective pressure of treatment with aromatase inhibitors in the adjuvant and metastatic settings and have important implications in the optimization of adjuvant and metastatic treatment in ER + breast cancer.

Treatment with aromatase inhibitors, a class of drugs that suppress the synthesis of estrogen, can drive the evolution of mutations in the estrogen receptor gene ESR1, leading to tumor resistance against hormone therapies. To better understand the emergence of ESR1 mutations, Rinath Jeselsohn from the Dana-Farber Cancer Institute 
in Boston, Massachusetts, USA, and coworkers tested tumor DNA contained within blood samples from 155 women with metastatic breast cancer. They found ESR1 mutations rarely in women with any molecular subtype of cancer other than estrogen receptor-positive disease. Nothing about the primary tumor predicted who would develop ESR1 mutations; however, treatment with an aromatase inhibitor was associated with mutations arising. The findings highlight the need to develop therapeutic regimens that reduce the selective pressure for ESR1 mutations and/or target these mutations directly.

Abstract 4564: The immune microenvironment in hormone receptor-positive breast cancer and treatment outcome following preoperative chemotherapy plus bevacizumab

Background: Hormone receptor-positive (HR+) breast cancers (BC) have fewer tumor-infiltrating lymphocytes (TILs) and lower response rates to immune checkpoint inhibitors in early phase studies than other breast cancer subtypes. Immune biomarkers that accurately reflect the immune microenvironment have important clinical implications in HR+ BC patients. Prior evidence suggests that macrophage-related immune pathways may be relevant to the pathophysiology of HR+ BC.

Methods: Patients identified from a prospective trial of preoperative bevacizumab (preop bev) followed by bev with adriamycin/cyclophosphamide/paclitaxel dose-dense chemotherapy (chemo). Tumor samples were collected at diagnosis and surgery (pre-tx and post-tx). TILs and immunohistochemical staining for PD-L1, CD8, and CD68 were scored. Whole transcriptome sequencing (RNAseq) and Nanostring PanCancer Immune Profiling Panel were performed. Pathologic response at surgery was assessed by Miller-Payne (MP) and residual cancer burden (RCB) scores. An immune score was calculated for each pre-tx specimen by integrating 10 published immune signatures. Immune cell subsets were inferred from bulk transcriptional data using CIBERSORT.

Results: 55 patients had at least 1 evaluable specimen and were included for analysis. 18% of pre-tx tumors had ‘high' (≥10%) TILs and ‘high' TILs were associated with significantly higher immune signature score (p=0.004). Immune score correlated highly with proportion of CIBERSORT anti-tumor M1 macrophage and CD8 T-cell signatures (r>0.65 and p<0.001) and was significantly associated with RCB. Higher pre-tx TILs, tPD-L1, sPD-L1, CD8, and CD68 were associated with favorable RCB significantly associated with more favorable RCB after adjustment for tumor size and grade. Pathologic complete response occurred in 4 pts; all 4 had high pre-tx TILs, pre-tx tPD-L1, or both. Among patients with residual disease, there were significantly fewer TILs and CD8 cells after chemotherapy (Wilcoxon signed rank p=0.037 and p=0.002, respectively), however tPD-L1 and CD68 were not significantly different. Nanostring analyses demonstrated that chemokines and complement pathway components were among most significantly enriched post-tx relative to pre-tx.

Conclusions: Most HR+/HER2- breast tumors demonstrate low levels of anti-tumor immune activity; however, those with higher levels have a more favorable response to chemo plus bev. Assessment of immune activity based on RNA signatures is consistent with histology and immune-related protein expression. T-cell- and checkpoint-related biomarkers tend to decrease following preoperative chemo plus bev in HR+/HER2- breast cancer. Following treatment with chemotherapy/bevacizumab, we observe increased expression of chemokines and complement pathway genes.

Citation Format: Adrienne G. Waks, Daniel G. Stover, William T. Barry, Deborah A. Dillon, Evisa Gjini, Scott J. Rodig, Jane E. Brock, Michele Baltay, Jennifer Savoie, Eric P. Winer, Ian E. Krop, Sara M. Tolaney. The immune microenvironment in hormone receptor-positive breast cancer and treatment outcome following preoperative chemotherapy plus bevacizumab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4564.

The Potential Impact of AMAROS on the Management of the Axilla in Patients with Clinical T1-2N0 Breast Cancer Undergoing Primary Total Mastectomy

BACKGROUND

Recent trials have demonstrated that axillary observation or axillary radiation therapy (AxRT) is equivalent to axillary node dissection (ALND) for patients with one or two positive sentinel lymph nodes (SLNs). These strategies have been widely adopted for patients having breast conservation. This report demonstrates the potential impact of the AMAROS trial on axillary therapy in a retrospective cohort of mastectomy patients.

METHODS

Patients undergoing primary mastectomy for cT1-2N0 breast cancer who had one or two positive SLNs were identified from institutional databases (2005-2015). Locoregional management strategies were evaluated, and variables predictive of the use of postmastectomy radiation therapy (PMRT) were identified.

RESULTS

Among 2594 mastectomies, 193 (7%) met the AMAROS eligibility criteria. The median patient age was 50 years (range 22-83 years). Locoregional treatment consisted of ALND + PMRT for 102 patients (53%), ALND alone for 66 patients (34%), PMRT alone for 11 patients (6%), and observation for 14 patients (7%). Overall, 59 ALND patients (35%) had additional positive nodes. In the multivariate analysis, age younger than 50 years (odds ratio [OR] 3.55; 95% confidence interval [CI] 1.57-8.45), lymphovascular invasion (LVI) (OR 5.78; 95% CI 2.53-4.78), macrometastases (OR 3.99; 95% CI 1.54-10.97), and extracapsular extension (OR 11.66; 95% CI 2.55-88.34) were associated with receipt of PMRT.

CONCLUSION

In this cohort of AMAROS-eligible patients, 168 (87%) underwent ALND, 102 (61%) of whom also received PMRT, suggesting that AxRT could have been used instead of ALND for a significant number of patients. Preoperative factors associated with the receipt of PMRT, such as young age and LVI, may be useful for defining a multidisciplinary decision-making framework for axillary management in this population.

Impact of neoadjuvant chemotherapy and pathological complete response on eligibility for breast-conserving surgery in patients with early breast cancer: A meta-analysis

PURPOSE

We conducted a meta-analysis of randomised trials evaluating pathological complete response (pCR) and surgical outcomes after neoadjuvant systemic therapy (NST) in patients with early breast cancer (EBC).

PATIENTS AND METHODS

The primary outcome was breast-conserving surgery (BCT) rate. Secondary outcomes were pCR rate and association to BCT. Meta-analyses were performed using random effects models that use inverse-variance weighting for each treatment arm based on evaluable patients. Point estimates are reported with 95% confidence interval (CI), and p < 0.05 was considered statistically significant.

RESULTS

Thirty-six studies were identified (N = 12,311 patients). We selected for the analysis 16 of 36 studies reporting both pCR and BCT for at least one treatment arm. Arms per study ranged from one to six; 42 independent units were available to evaluate the association between pCR and BCT. BCT rate ranged 5-76% across arms with an average BCT of 57% (95% CI 52-62%). Significant heterogeneity was observed among the trials (Cochrane Q = 787, p < 0.001, I² = 97%). In the meta-regression model, BCT rates were not significantly associated with year of first patient-in (p = 0.89), grade (p = 0.93) and hormone-receptor status (p = 0.39). Clinical N-stage (p = 0.01) and human epidermal growth factor receptor (HER2) status (p = 0.03) were significantly associated with BCT. pCR rate ranged 3-60% across studies. The average pCR across all study arms was 24% (95% CI 19-29%). No association was observed between pCR rate in a study arm and the resulting BCT rate in a univariate model (p = 0.34) nor after adjusting for HER2 and clinical nodal status (p = 0.82). In the subset of 14 multi-arm studies, no significant association was seen between the differences in pCR and BCT between treatment arms (p = 0.27).

CONCLUSIONS

pCR does not increase BCT in patients receiving NST for EBC.

Expanded Genomic Profiling of Circulating Tumor Cells in Metastatic Breast Cancer Patients to Assess Biomarker Status and Biology Over Time (CALGB 40502 and CALGB 40503, Alliance)

Purpose: We profiled circulating tumor cells (CTCs) to study the biology of blood-borne metastasis and to monitor biomarker status in metastatic breast cancer (MBC).Methods: CTCs were isolated from 105 patients with MBC using EPCAM-based immunomagnetic enrichment and fluorescence-activated cells sorting (IE/FACS), 28 of whom had serial CTC analysis (74 samples, 2-5 time points). CTCs were subjected to microfluidic-based multiplex QPCR array of 64 cancer-related genes (n = 151) and genome-wide copy-number analysis by array comparative genomic hybridization (aCGH; n = 49).Results: Combined transcriptional and genomic profiling showed that CTCs were 26% ESR1-ERBB2-, 48% ESR1+ERBB2-, and 27% ERBB2+ Serial testing showed that ERBB2 status was more stable over time compared with ESR1 and proliferation (MKI67) status. While cell-to-cell heterogeneity was observed at the single-cell level, with increasingly stable expression in larger pools, patient-specific CTC expression "fingerprints" were also observed. CTC copy-number profiles clustered into three groups based on the extent of genomic aberrations and the presence of large chromosomal imbalances. Comparative analysis showed discordance in ESR1/ER (27%) and ERBB2/HER2 (23%) status between CTCs and matched primary tumors. CTCs in 65% of the patients were considered to have low proliferation potential. Patients who harbored CTCs with high proliferation (MKI67) status had significantly reduced progression-free survival (P = 0.0011) and overall survival (P = 0.0095) compared with patients with low proliferative CTCs.Conclusions: We demonstrate an approach for complete isolation of EPCAM-positive CTCs and downstream comprehensive transcriptional/genomic characterization to examine the biology and assess breast cancer biomarkers in these cells over time. Clin Cancer Res; 24(6); 1486-99. ©2018 AACR.

Association of Cell-Free DNA Tumor Fraction and Somatic Copy Number Alterations With Survival in Metastatic Triple-Negative Breast Cancer

Purpose Cell-free DNA (cfDNA) offers the potential for minimally invasive genome-wide profiling of tumor alterations without tumor biopsy and may be associated with patient prognosis. Triple-negative breast cancer (TNBC) is characterized by few mutations but extensive somatic copy number alterations (SCNAs), yet little is known regarding SCNAs in metastatic TNBC. We sought to evaluate SCNAs in metastatic TNBC exclusively via cfDNA and determine if cfDNA tumor fraction is associated with overall survival in metastatic TNBC. Patients and Methods In this retrospective cohort study, we identified 164 patients with biopsy-proven metastatic TNBC at a single tertiary care institution who received prior chemotherapy in the (neo)adjuvant or metastatic setting. We performed low-coverage genome-wide sequencing of cfDNA from plasma. Results Without prior knowledge of tumor mutations, we determined tumor fraction of cfDNA for 96.3% of patients and SCNAs for 63.9% of patients. Copy number profiles and percent genome altered were remarkably similar between metastatic and primary TNBCs. Certain SCNAs were more frequent in metastatic TNBCs relative to paired primary tumors and primary TNBCs in publicly available data sets The Cancer Genome Atlas and METABRIC, including chromosomal gains in drivers NOTCH2, AKT2, and AKT3. Prespecified cfDNA tumor fraction threshold of ≥ 10% was associated with significantly worse metastatic survival (median, 6.4 v 15.9 months) and remained significant independent of clinicopathologic factors (hazard ratio, 2.14; 95% CI, 1.4 to 3.8; P < .001). Conclusion We present the largest genomic characterization of metastatic TNBC to our knowledge, exclusively from cfDNA. Evaluation of cfDNA tumor fraction was feasible for nearly all patients, and tumor fraction ≥ 10% is associated with significantly worse survival in this large metastatic TNBC cohort. Specific SCNAs are enriched and prognostic in metastatic TNBC, with implications for metastasis, resistance, and novel therapeutic approaches.

Abstract OT1-02-02: A phase II study of pembrolizumab in combination with palliative radiotherapy for metastatic hormone receptor positive breast cancer

BACKGROUND: Despite recent advances in the treatment of patients with metastatic hormone receptor positive (HR+)/HER2- breast cancer (BC), it remains an incurable disease. The activity of immune checkpoint inhibitors (ICI) as monotherapy in patients with metastatic HR+/HER2- BC has been limited. Therefore, the addition of other strategies that elicit an immunogenic tumor microenvironment may be needed. We hypothesize that radiation therapy (RT) will potentiate the efficacy of the PD-1 inhibitor pembrolizumab in patients with metastatic HR+/HER2- BC. METHODS: Trial Design: This is a phase II single arm study assessing objective response rate (ORR) according to RECIST 1.1 in patients with metastatic HR+/HER2- BC who will receive pembrolizumab in combination with palliative RT. Pembrolizumab 200 mg intravenously will be administered 2-7 days before day 1 of RT, and will be given every 21 days until disease progression. Biopsies will be performed in the same lesion at baseline (mandatory if tumor tissue is accessible outside the field of RT) and during cycle 2 within 7-14 days before the day 1 of cycle 3 of pembrolizumab. Key Eligibility Criteria: Patients with metastatic HR+/HER2- BC, with measurable disease outside the field of radiation, for whom palliative RT to at least one bone, lymph node, or soft tissue lesion is indicated. Radiation of visceral lesions (such as lung or hepatic lesions) is not permitted. Although prior RT is allowed, patients must be at least 3 months free from RT; Re-irradiation of the same field is not allowed. There is no limit to the number of previous treatments, and systemic treatment naive patients for metastatic disease are also eligible. Specific Aims: The primary aim is to evaluate the efficacy of the combination, as defined by objective response rate (ORR) outside the field of RT according to RECIST 1.1. Secondary objectives include to determine the ORR according to immune-related criteria, the progression-free survival, the abscopal response rate, the clinical benefit rate, the safety and the tolerability of the combination. In addition, correlative studies will be performed to explore the correlation of immunosuppressive and/or immune-stimulating immune marker profiles at baseline and after cycle 2 to disease response to therapy. Statistical Methods: Using the Simons “optimal” method, in the first stage, 8 patients will be enrolled. If there is at least 1 response, accrual will continue to the second stage where up to 19 additional patients will be enrolled. If at least 3 of these 27 patients have an objective response (≥10%), the regimen will be considered worthy of further study. With this design, the probability of stopping the trial early is 78% if the true response rate is 3%. If the true response rate is 20% the chance that the regimen is declared worthy of further study is 80%. Patient accrual and target accrual: The trial opened in April/2017, and so far, has accrued 2 patients with a target accrual of 27 patients. Accrual should be complete in 14-25 months. Clinical trial information: NCT03051672.

Citation Format: Barroso-Sousa R, Gao H, Barry WT, Krop IE, Schoenfeld JD, Tolaney SM. A phase II study of pembrolizumab in combination with palliative radiotherapy for metastatic hormone receptor positive breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-02-02.

Abstract P1-07-04: Physical activity, weight and outcomes in patients receiving first-line chemotherapy for metastatic breast cancer: Results from CALGB 40502 (Alliance)

Background: Obesity and inactivity are associated with an increased risk of cancer-related and overall mortality in women with early-stage breast cancer, but there are few data in advanced breast cancer.

Methods: C40502 was a Phase III trial of first-line chemotherapy for patients with metastatic breast cancer (MBC). Participants were randomized to weekly paclitaxel, nab-paclitaxel or ixabepilone. Height and weight at the time of study enrollment were abstracted from medical records. After study activation, the protocol was amended to collect physical activity (PA) data. Participants completed the Nurses' Health Study Exercise Questionnaire, indicating the frequency, type and duration of recreational PA in which they engaged at study enrollment. Metabolic equivalent (MET)-hours of weekly PA (MET-hrs/wk) were calculated using the Ainsworth Compendium. PA was dichotomized to 0-9 or 9+ MET-hrs/wk based on data in early stage breast cancer suggesting that women who engaged in &gt; 9 MET-hrs of PA/wk had lower cancer-specific mortality. Association with clinical endpoints was evaluated using multivariate Cox proportional hazard models adjusting for treatment assignment, age, tumor hormone-receptor status, prior taxane use, disease-free interval and visceral metastases.

Results: 799 patients enrolled in C40502 between 2008 and 2011. Baseline body mass index (BMI) was available for 792 patients and PA data for 500 participants. Median follow up was 60 months. Median age was 56.7 years; 72% of patients had hormone receptor (HR)-positive cancers. Median BMI was 28.6 kg/m2 (IQR: 24.7-33.1 kg/m2). Patients engaged in a median of 3.3 MET-hrs/wk of PA (about 1 hour of moderate-intensity PA/wk) (IQR: 0.7-12.7 MET-hrs/wk). Neither BMI nor PA was significantly associated with progression-free (PFS) or overall survival (OS).

BMI and OutcomesBMI (kg/m2)N (%)PFS (months)Adj HRP valueOS (months)Adj HRP value18.5-24.9209 (26.4)10.0 (9.1-11.2)ref0.4826.1 (23.3-33.2)ref0.5425-29.9248 (31.3)9.0 (7.6-10.3)1.00 (0.83-1.22) 22.0 (20.0-25.4)1.05 (0.85-1.30) ≥30335 (42.3)8.7 (7.7-9.7)0.97 (0.81-1.17) 25.5 (23.1-29.5)0.95 (0.78-1.16) 

PA and OutcomesPA (MET-hrs/wk)N (%)PFS (months)Adj HRP valueOS (months)Adj HRP value0-9344 (68.8)7.9 (7.4-9.2)ref0.1323.6 (20.1-26.8)ref0.21&gt;9156 (31.2)9.8 (8.9-12.0)0.86 (0.71-1.05) 27.4 (22.3-35.6)0.87 (0.70-1.08) 

There was a trend toward longer PFS and OS in patients who reported PA &gt; 9 MET-hrs/wk vs 0-9 MET-hrs/wk, especially in individuals with HR+ cancers (median PFS 11.7 vs 9.2 months [adj HR = 0.84 (0.66-1.05)] and OS 34.0 vs 26.5 months [adj HR = 0.83 (0.66-1.05)] with PA &gt;9 vs 0- 9 MET-hrs/wk).

Conclusions: In some of the first data looking at the relationship between lifestyle factors and outcomes in MBC, there was no relationship between BMI and PFS or OS in patients receiving first-line chemotherapy for advanced disease. A trend toward improved PFS and OS was seen in multivariate analysis in patients who reported higher levels of PA, but results were not statistically significant and could have been influenced by other patient factors. More information is needed regarding the relationship between PA and cancer outcomes, especially in patients with HR+ cancers.

Citation Format: Ligibel JA, Huebner LJ, Rugo HS, Burstein H, Toppmeyer DL, Anders CK, Ma C, Hudis CA, Winer EP, Barry WT. Physical activity, weight and outcomes in patients receiving first-line chemotherapy for metastatic breast cancer: Results from CALGB 40502 (Alliance) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-07-04.

Abstract P2-01-01: Trajectory patterns of circulating tumor cells (CTC) in chemotherapy-treated metastatic breast cancer (MBC) patients predict poor clinical outcomes: CALGB 40502 (Alliance)/NCCTG N063H study

Little is known about the dynamics of CTCs during treatment and its clinical significance. We examined the predictive utility of serial CTC analysis in ER+HER2- MBC patients (pts) treated with chemotherapy in the CALGB 40502/NCCTG N063H study, a randomized phase III trial of weekly paclitaxel compared to weekly nanoparticle albumin bound nab-paclitaxel or ixabepilone +/- bevacizumab as first-line therapy (ClinicalTrials.gov Identifier: NCT00785291, Support: U10CA180821, U10CA180882).

Methods: Of the 783 pts treated, 469 had ≥3 serial blood samples (including baseline) successfully analyzed for CTCs by CellSearch® and were included in this analysis (n=2,202). Samples with ≥5 CTCs per 7.5 mLs of blood were considered CTC+. The prognostic and predictive performance of baseline CTCs (bCTC) and CTC status from baseline to cycle 2 (b2CTC) were compared to a novel latent mixture model classification based on trajectory of CTCs (tCTC). Akaike Information Criterion (AIC) was used to select the model (bCTC vs b2CTC vs tCTC) that best predicts overall survival (OS), progression-free survival (PFS), and time-to-treatment failure (TTF).

Results: 53% of the pts were CTC+ at baseline. b2CTC status changed in 36% of the pts, most of whom were CTC+CTC- (35%), and very few CTC-CTC+ (1%); the rest of the pts did not experience a change in b2CTC status (46% CTC-CTC- and 19% CTC+CTC+). Mixture model analysis revealed 4 groups of pts that show distinct tCTC patterns over the course of treatment: consitently very low/undectectable CTCs (tCTCneg, 56%), low (tCTClo, 24%), intermediate (tCTCmid, 15%), or high (tCTChi, 5%). bCTC, b2CTC, and tCTC were significantly correlated with tumor subtype (all p &lt;0.0022) and presence of bone metastasis (all p &lt;0.0001). Multivariate analysis showed that pts who were CTC+ at baseline, and those whose b2CTC status remained positive (CTC+CTC+) had significantly reduced OS, PFS and TTF.

 OSPFSTTFModelsHR (95% CI)p-valueHR (95% CI)p-valueHR (95% CI)p-valuebCTC (vs CTC-)      → CTC+2.5(1.8-3.3)&lt;0.00011.6(1.3-2.0)&lt;0.00011.3(1.1-1.6)0.0046b2CTC (vs CTC+CTC-)      → CTC-CTC+1.6(0.5-5.4)0.41491.6(0.6-4.5)0.39051.6(0.6-4.3)0.3961→ CTC+CTC+2.7(1.9-3.8)&lt;0.00011.8(1.4-2.5)&lt;0.00011.8(1.3-2.4)&lt;0.0001→ CTC-CTC-0.5(0.4-0.8)0.00020.8(0.6-0.9)0.01600.9(0.7-1.1)0.2771tCTC (vs tCTCneg)      → tCTClo2.6(1.9-3.7)&lt;0.00011.9(1.4-2.4)&lt;0.00010.9(0.7-1.1)0.0033→ tCTCmid5.3(3.6-8.0)&lt;0.00012.5(1.8-3.4)&lt;0.00011.8(1.4-2.5)0.0001→ tCTChi10.8(6.1-19)&lt;0.00013.0(1.8-5.0)&lt;0.00012.3(1.4-3.7)0.0009CTC- (&lt;5 CTCs per 7.5 mLs); CTC+ (≥5 CTCs per 7.5 mLs)

Pts with tCTClo, tCTCmid and tCTChi had significantly shorter OS, PFS and TTF compared to those with tCTCneg. After adjustment for potential confounders, AIC analysis revealed that the tCTC model best predicts OS and PFS, while b2CTC best predicts TTF.

 AIC Score*ModelsOSPFSTTFbCTC243240514199b2CTC240540384186tCTC237940264188*The lowest AIC score indicates the best model.

Conclusions: Analysis of CTC trajectory patterns identified pts with poor outcome who could potentially benefit from more effective treatment. Validation in independent cohorts is warranted to confirm the findings in this study.

Citation Format: Magbanua MJ, Hendrix L, Hyslop T, Barry WT, Winer EP, Hudis C, Toppmeyer D, Burnstein H, Qadir M, Ma C, Scott JH, Park JW, Rugo HS. Trajectory patterns of circulating tumor cells (CTC) in chemotherapy-treated metastatic breast cancer (MBC) patients predict poor clinical outcomes: CALGB 40502 (Alliance)/NCCTG N063H study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-01-01.

Kinetic-Pharmacodynamic Model of Chemotherapy-Induced Peripheral Neuropathy in Patients with Metastatic Breast Cancer Treated with Paclitaxel, Nab-Paclitaxel, or Ixabepilone: CALGB 40502 (Alliance)

Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting toxicity caused by several chemotherapeutic agents. Currently, CIPN is managed by empirical dose modifications at the discretion of the treating physician. The goal of this research is to quantitate the dose-CIPN relationship to inform the optimal strategies for dose modification. Data were obtained from the Cancer and Leukemia Group B (CALGB) 40502 trial, a randomized phase III trial of paclitaxel vs. nab-paclitaxel vs. ixabepilone as first-line chemotherapy for locally recurrent or metastatic breast cancer. CIPN was measured using a subset of the Functional Assessment of Cancer Therapy-Gynecologic Oncology Group Neurotoxicity (FACT-GOG-NTX) scale. A kinetic-pharmacodynamic (K-PD) model was utilized to quantitate the dose-CIPN relationship simultaneously for the three drugs. Indirect response models with linear and Smax drug effects were evaluated. The model was evaluated by comparing the predicted proportion of patients with CIPN (score ≥8 or score ≥12) to the observed proportion. An indirect response model with linear drug effect was able to describe the longitudinal CIPN data reasonably well. The proportion of patients that were falsely predicted to have CIPN or were falsely predicted not to have CIPN was 20% or less at any cycle. The model will be utilized to identify an early time point that can predict CIPN at later time points. This strategy will be utilized to inform dose adjustments to prospectively manage CIPN. Clinicaltrials.gov ID: NCT00785291.

Abstract 4950: The emergence of ESR1 mutations is associated with aromatase inhibitor and fulvestrant therapy

Introduction: In recent studies, constitutively active recurrent ESR1 ligand binding mutations (LBD) were found in about 20% of metastatic (met) HR+ breast cancers ( BRCAs) and rarely in primary HR+ cancers. In our previous work, we analyzed clinical tissue samples and detected an association between the number of prior endocrine treatments and the prevalence of these mutations, suggesting the emergence of the ESR1 mutations under the selective pressure of endocrine treatment. More recently, the LBD ESR1 mutations were successfully detected in plasma cell free (cf)DNA in patients with met HR+ disease. The presence of mutant ESR1 cfDNA was found to be prognostic. Here we sought to study the association between endocrine treatments in the adjuvant (adj) and met settings and the prevalence of cfDNA ESR1 and PIK3CA mutations in patients with met HR+ BRCA.

Methods: Plasma samples and detailed clinical data were collected from patients with met BRCA through the Collection of Specimens and Clinical Data program of the Breast Oncology Center at the Dana Farber Cancer Institute. Droplet Digital PCR was used for the detection of the most common ESR1 LBD mutations (E380Q, Y537C, Y537N, Y537S and D538G) and the 3 most common PIK3CA mutations (E542K, E545K and H1047R) in cfDNA. Fisher’s Exact Test was used for statistical analysis.

Results: Plasma samples were collected from 155 patients with met BRCA. ESR1 mutations were found in 30.1% of the patients with HR+/HER2- negative disease (34/113). PIK3CA mutations were detected in 31.8% of patients with HR+/HER2- disease. The majority of the patients had either newly diagnosed met disease or progressive met disease at the time of the blood draw. 14 patients had stable met disease and among these patients, only 1 of these patients was found to have an ESR1 mutation and no PIK3CA mutations were detected. The majority of patients with ESR1 mutations (88%) and PIK3CA mutations (75%) had progressive disease. Patients that received an aromatase inhibitor (AI) either in the adj or met setting had a higher prevalence of ESR1 mutations compared to patients that had no AI treatment, regardless of whether or not they received tamoxifen (TAM) (prevalence was 32% for adj AI only, 40.4% AI in met only, No AI and no TAM 7.1% and TAM but no AI 6.7%). In addition fulvestrant treatment in the met setting was significantly associated with ESR1 mutations (odds ratio 3.38, p-value&lt;0.01). Conversely, we did not detect any significant associations between endocrine treatments in the adj or met settings and PIK3CA mutations.

Conclusions: Analysis of cfDNA can successfully detect ESR1 and PIK3CA mutations in newly diagnosed or progressive met BRCA patients and the emergence of the ESR1 mutations is associated with AI and fulvestrant treatment. These results support the serial monitoring of ESR1 mutations in cfDNA in met disease and highlight the need to study new agents to target these mutations.

Citation Format: Yanan Kuang, Bilal Siddiqui, Jiani Hu, William T. Barry, Nancy U. Lin, Nikhil Wagle, Paul Kirschmeier, Pasi A. Jänne, Cloud Paweletz, Ian Krop, Eric P. Winer, Myles Brown, Rinath Jeselsohn. The emergence of ESR1 mutations is associated with aromatase inhibitor and fulvestrant therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4950. doi:10.1158/1538-7445.AM2017-4950

Abstract CT008: Phase I study of the alpha specific PI3-Kinase inhibitor BYL719 and the poly (ADP-Ribose) polymerase (PARP) inhibitor olaparib in recurrent ovarian and breast cancer: Analysis of the dose escalation and ovarian cancer expansion cohort

Background: In vivo synergy with concurrent PI3-Kinase inhibition and PARP inhibition has been observed in BRCA-deficient and BRCA-proficient preclinical models of triple negative breast cancer (TNBC) and ovarian cancer (OC). A phase I trial of the oral pan-class I PI3-Kinase inhibitor BKM120 and the PARP inhibitor olaparib demonstrated anti-cancer activity in TNBC and OC, both in patients with and without germline BRCA1 and BRCA2 (BRCA) mutations. However, CNS toxicity (depression) and liver function test abnormalities limited dose escalation of BKM120 prompting evaluation of the alpha specific PI3-Kinase inhibitor BYL719 (which has no CNS toxicity) in combination with olaparib.

Methods: Olaparib was administered twice daily (tablet formulation) and BYL719 daily on a 28-day cycle, both orally. A 3 + 3 dose-escalation design was employed with primary objectives of defining the maximum tolerated dose (MTD) and recommended phase 2 dose of the combination of BYL719 and olaparib, and secondary objectives of defining toxicity, activity, and pharmacokinetic profiles of both agents. Eligibility included recurrent TNBC or high grade serous (HGS) OC, or any histology OC or breast cancer (BC) with presence of a known germline BRCA mutation, performance status of 0-1 and measurable/evaluable cancer. Patients with platinum sensitive or resistant or refractory OC were eligible and prior PARP inhibitor use was allowed. Dose-expansion cohorts at the MTD were enrolled for both BC and OC.

Results: 46 patients (16 BC and 30 OC) have been enrolled in the study; 28 patients participated in the dose escalation portion of the study (4 BC and 24 OC). Two patients with OC did not receive study drugs because of ineligibility. MTD was defined as BYL719 200mg once daily and olaparib 200mg twice daily. Dose limiting toxicities included hyperglycemia, rash and fever with decreased neutrophil count. Four patients (3 OC and 1 BC) discontinued protocol therapy because of toxicity (2 for hyperglycemia, 1 for nausea and 1 for allergic reaction). Most common toxicities included nausea, hyperglycemia, fatigue, diarrhea and vomiting. At the MTD, 6 patients with OC and 12 patients with BC were enrolled into a dose expansion cohort. The OC expansion cohort has completed enrollment, while the BC cohort is still enrolling. Among patients with OC who received study drugs (28 patients, 26 (93%) with platinum resistant disease), objective response rate (ORR) by RECIST 1.1 was 36% (10/28 patients, all partial responses (PRs)). Median duration of response was 167 days (range 16-398 days); 5 of 10 patients with PR remain on treatment. ORR was 33% for patients with germline BRCA mutations and 31% for patients without germline BRCA mutations. Among patients without germline BRCA mutations with platinum resistant OC, ORR was 29%.

Conclusions: Combined BYL719 and olaparib is feasible, and similar clinical benefit was observed in patients with and without germline BRCA mutations. The activity of this combination in OC patients without germline BRCA mutations and with platinum resistant disease was higher than expected from olaparib monotherapy and warrants further investigation. This work was funded in part by the Stand Up To Cancer Ovarian Dream Team. Clinical trial: NCT01623349.

Citation Format: Panagiotis A. Konstantinopoulos, William T. Barry, Michael Birrer, Shannon N. Westin, Sarah Farooq, Karen Cadoo, Christin Whalen, Weixiu Luo, Hui Liu, Carol Aghajanian, David B. Solit, Gordon B. Mills, Barry S. Taylor, Helen Won, Michael F. Berger, Sangeetha Palakurthi, Joyce F. Liu, Lew Cantley, Scott H. Kaufmann, Elizabeth M. Swisher, Alan D. D'Andrea, Eric Winer, Gerburg M. Wulf, Ursula A. Matulonis. Phase I study of the alpha specific PI3-Kinase inhibitor BYL719 and the poly (ADP-Ribose) polymerase (PARP) inhibitor olaparib in recurrent ovarian and breast cancer: Analysis of the dose escalation and ovarian cancer expansion cohort [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT008. doi:10.1158/1538-7445.AM2017-CT008

Abstract NTOC-112: GENOMIC SCARS AND CLINICAL RESPONSE TO COMBINATION THERAPY OF PARP AND ANGIOGENESIS INHIBITORS IN OVARIAN CANCER

BACKGROUND: Genomic instability, frequently resulting in chromosomal allelic deletion with allelic imbalance (AI)/loss of heterozygosity (LOH), is characteristic of high-grade serous ovarian cancer (HGSOC). Frequent allelic deletion is thought to arise from deficiency in DNA repair by homologous recombination (HR) resulting in the so called “genomic scars” of HR deficiency. Quantification of AI/LOH events in the tumor genome has previously been shown to predict response to therapy using platinum compounds. Recently, PARP inhibitors have proved useful in treating a sub-set of patients with HGSOC, particularly tumors harboring BRCA1/2 mutations. Combination with an angiogenesis inhibitor significantly improved the outcome. This study explores the potential of using AI/LOH scores to predict clinical response of HGSOC to PARP inhibition alone or in combination with an angiogenesis inhibitor.

MATERIALS AND METHODS: Molecular inversion probe array data were generated using tumors from a sub-set of patients (n=37) enrolled in a clinical trial comparing the PARP inhibitor Olaparib to the combination of Olaparib with the anti-angiogenic agent Cediranib (NCT01116648). AI/LOH regions were identified using an ASCAT based algorithm. Markers of genomic instability associated with DNA repair deficiency were scored. These quantify AI regions (NAI), telomeric AI (NtAI), large scale transition (LST), fraction of LOH (FLOH), and HRD-LOH. dChip was used for copy number analysis. The best overall response to therapy was determined using the RECIST 1.1 criteria for complete and partial response (CR, n = 3 and PR, n = 18), and stable disease without objective response (SD, n = 16).

RESULTS: A high tumor NAI-score was positively correlated with the degree of clinical response to therapy (either olaparib alone or in combination with cediranib) (Chi-square test for trend, p = 0.036). This association remains statistically significant in the subgroup carrying BRCA mutations (n = 22, Chi-square test for trend, p = 0.0488). In this limited sample, the objective response rate of high NAI tumors to the combination therapy was high (7 out of 8), especially in patient carrying wild-type BRCA1/2 genes (2 out of 2, p = 0.045). The results suggest NAI may be a potential genomic marker for response to the therapy combining PARP and angiogenesis inhibitors. However, no significant association was observed between the degree of objective response and scores of other genomic measurements NtAI, LST, or HRD-LOH.

SUMMARY: High NAI-score was associated with objective response to olaparib, alone or in combination with cediranib, supporting NAI as a candidate of genomic marker for predicting response to PARP inhibitor-based therapy in HGSOC. A larger cohort would be required to further evaluate predictive value of NAI for response to the combinational therapy.

Citation Format: Zhigang C. Wang, Nicolai Juul Birkbak, William T. Barry, Thomas M. Roberts, Eric P. Winer, J Dirk Iglehart, Ursula A. Matulonis, S. Percy Ivy, and Joyce F. Liu. GENOMIC SCARS AND CLINICAL RESPONSE TO COMBINATION THERAPY OF PARP AND ANGIOGENESIS INHIBITORS IN OVARIAN CANCER [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr NTOC-112.

Population-Based Analysis of Breast Cancer Incidence and Survival Outcomes in Women Diagnosed with Lobular Carcinoma In Situ

PURPOSE

A diagnosis of lobular carcinoma in situ (LCIS) is associated with an increased risk of developing breast cancer, although little data exist on long-term patient outcomes, including those who develop subsequent breast malignancies.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify women with a histological diagnosis of LCIS between 1983 and 2014. The incidence and clinicopathologic features of subsequent malignancies were then examined, and the Kaplan-Meier method and multivariable Cox PH regression used to obtain breast cancer-specific survival (BCSS) estimates and associated hazard ratios.

RESULTS

Overall, 19,462 women swith a mean age at LCIS diagnosis of 53.7 years, and a 10- and 20-year cumulative incidence of subsequent breast malignancy of 11.3% [95% confidence interval (CI) 10.7-11.9%] and 19.8% (95% CI 18.8-20.9) met the eligibility criteria. At a median follow-up of 8.1 years (range 0-30.9) a total of 1837 primary breast cancers were diagnosed, of which 55.2% were diagnosed in the ipsilateral breast. Most breast cancers were of low/intermediate grade, hormone receptor-positive, and diagnosed in early stages. Of subsequent malignancies, invasive ductal carcinoma (IDC) distributed equally across both breasts, whereas invasive lobular carcinoma (ILC) was more likely to present in the ipsilateral breast (69.0% ILC vs. 49.2% IDC; p < 0.001). On multivariable analysis, type of surgical treatment for LCIS had no affect on long-term survival (p = 0.44). The 10- and 20-year BCSS for women with LCIS was 98.9 and 96.3%, respectively.

CONCLUSION

Women with LCIS who are diagnosed with a subsequent primary breast cancer are often diagnosed in early stages and have excellent BCSS.

Evidence for Feedback Regulation Following Cholesterol Lowering Therapy in a Prostate Cancer Xenograft Model

BACKGROUND

Epidemiologic data suggest cholesterol-lowering drugs may prevent the progression of prostate cancer, but not the incidence of the disease. However, the association of combination therapy in cholesterol reduction on prostate or any cancer is unclear. In this study, we compared the effects of the cholesterol lowering drugs simvastatin and ezetimibe alone or in combination on the growth of LAPC-4 prostate cancer in vivo xenografts.

METHODS

Proliferation assays were conducted by MTS solution and assessed by Student's t-test. 90 male nude mice were placed on a high-cholesterol Western-diet for 7 days then injected subcutaneously with 1 × 10⁵ LAPC-4 cells. Two weeks post-injection, mice were randomized to control, 11 mg/kg/day simvastatin, 30 mg/kg ezetimibe, or the combination and sacrificed 42 days post-randomization. We used a generalized linear model with the predictor variables of treatment, time, and treatment by time (i.e., interaction term) with tumor volume as the outcome variable. Total serum and tumor cholesterol were measured. Tumoral RNA was extracted and cDNA synthesized from 1 ug of total RNA for quantitative real-time PCR.

RESULTS

Simvastatin directly reduced in vitro prostate cell proliferation in a dose-dependent, cell line-specific manner, but ezetimibe had no effect. In vivo, low continuous dosing of ezetimibe, delivered by food, or simvastatin, delivered via an osmotic pump had no effect on tumor growth compared to control mice. In contrast, dual treatment of simvastatin and ezetimibe accelerated tumor growth. Ezetimibe significantly lowered serum cholesterol by 15%, while simvastatin had no effect. Ezetimibe treatment resulted in higher tumor cholesterol. A sixfold induction of low density lipoprotein receptor mRNA was observed in ezetimibe and the combination with simvastatin versus control tumors.

CONCLUSIONS

Systemic cholesterol lowering by ezetimibe did not slow tumor growth, nor did the cholesterol independent effects of simvastatin and the combined treatment increased tumor growth. Despite lower serum cholesterol, tumors from ezetimibe treated mice had higher levels of cholesterol. This study suggests that induction of low density lipoprotein receptor is a possible mechanism of resistance that prostate tumors use to counteract the therapeutic effects of lowering serum cholesterol. Prostate 77:446-457, 2017. © 2016 Wiley Periodicals, Inc.

Patterns of Utilization of Imaging Studies and Serum Tumor Markers Among Patients With De Novo Metastatic Breast Cancer

Background: When monitoring patients with metastatic breast cancer (mBC), the optimal strategies for imaging and utilization of tumor markers (TM) are uncertain. Patients and Methods: We used a retrospective cohort of 302 patients with de novo mBC treated from 2000 to 2012 at Dana-Farber Cancer Institute to describe the type and timing of imaging and TM testing during the first line of treatment (baseline, first, and subsequent testing). Results: At baseline, all patients had staging scans, with increasing use of PET/PET-CT (17.5% from 2000-2002; 40.3% from 2009-2012). PET/PET-CT was used by itself in only 12.5% of cases. Overall, 30.1% of patients, of whom 80.2% had no neurologic symptoms, underwent central nervous system (CNS) screening; 78.2% of patients had baseline TM testing. Over the course of treatment, 23.5% of patients had TM retested once a month or more. Time-to-first reimaging varied by disease site (hazard ratios for shorter time-to-first reimaging [95% CI] vs bone: brain, 4.27 [1.46-12.50]; liver, 2.19 [1.39-3.46]; lung, 2.75 [1.66-4.57]), but was not associated with tumor subtype or baseline TM testing, regardless of test results. First reimaging was prompted by an elevation in TM in only 1.4% of cases. There was weak correlation between frequency of imaging and TM tests (r=0.33; R² =0.11; P<.001). Discussion: Over time, we found an increased utilization of more sophisticated imaging staging techniques, such as PET/PET-CT scan, which was mostly requested in addition to other radiographic studies. CNS evaluations were frequently performed to screen asymptomatic patients. TM testing was often ordered, both at baseline and after treatment initiation. However, patterns of imaging utilization, although appropriately influenced by clinicopathologic factors such as disease site, did not appear to be impacted by TM testing. Conclusions: Studies focused on optimizing disease monitoring, including better integration of TM testing with imaging, are encouraged.

Factors Associated with Early Mortality Among Patients with De Novo Metastatic Breast Cancer: A Population-Based Study

BACKGROUND

Although improvements in survival have been achieved for patients with metastatic breast cancer, some patients experience early death after diagnosis.

PATIENTS AND METHODS

Using Surveillance, Epidemiology, and End Results data, we identified 26,538 patients with de novo metastatic breast cancer diagnosed between January 1, 2000 and June 30, 2011. We evaluated time trends for deaths at 1 and 6 months after diagnosis. We then restricted the cohort to patients diagnosed between 2010 and 2011 (n = 3,317), when human epidermal growth factor receptor 2 was routinely collected, and examined factors associated with early death.

RESULTS

In 2000, 15.9% of patients died within 1 month of diagnosis and 33.2% within 6 months. In 2011, the proportion of women dying within 1 month decreased to 13.4% and 26.3% within 6 months (p < .001). Older age and uninsured status were associated with early death (at both time points, age ≥70 [versus age <40] had >8.5 higher odds of dying, and uninsured [versus insured] patients had >2.5 higher odds of death). In addition, in some subgroups (e.g., no insurance and triple negative disease), more than half of patients died within 6 months. Region was also associated with early death.

CONCLUSION

Although we observed improvements in the proportion of patients experiencing early death, one quarter of patients with de novo metastatic disease diagnosed in 2011 died within 6 months of diagnosis. In addition to tumor factors and older age, geography and uninsured status were associated with early death. Our findings highlight the need for focused interventions for metastatic patients at highest risk for poor outcomes. The Oncologist 2017;22:386-393 IMPLICATIONS FOR PRACTICE: With nearly one quarter of patients in our dataset diagnosed in 2011 dying within 6 months of diagnosis, our findings highlight the persistent and critical need of further characterization and identification of patients who are risk for poor outcomes in order to optimize care, impact change, and improve outcomes for all women with metastatic breast cancer. Our data also emphasize the need for interventions among those at highest risk for early death. These interventions would likely promote immediate referral for clinical trial participation, early palliative care referrals, and additional supportive services, optimizing equitable patient access to cancer treatment and care.

Bayesian response-adaptive designs for basket trials

We develop a general class of response-adaptive Bayesian designs using hierarchical models, and provide open source software to implement them. Our work is motivated by recent master protocols in oncology, where several treatments are investigated simultaneously in one or multiple disease types, and treatment efficacy is expected to vary across biomarker-defined subpopulations. Adaptive trials such as I-SPY-2 (Barker et al., 2009) and BATTLE (Zhou et al., 2008) are special cases within our framework. We discuss the application of our adaptive scheme to two distinct research goals. The first is to identify a biomarker subpopulation for which a therapy shows evidence of treatment efficacy, and to exclude other subpopulations for which such evidence does not exist. This leads to a subpopulation-finding design. The second is to identify, within biomarker-defined subpopulations, a set of cancer types for which an experimental therapy is superior to the standard-of-care. This goal leads to a subpopulation-stratified design. Using simulations constructed to faithfully represent ongoing cancer sequencing projects, we quantify the potential gains of our proposed designs relative to conventional non-adaptive designs.

Abstract P1-07-05: Integrated transcriptional analysis of the triple negative 'proliferation paradox': High proliferation, chemosensitivity, and poor prognosis

Background: In triple-negative breast cancers (TNBC), high proliferation is associated with greater chemosensitivity but, paradoxically, also associated with poor prognosis. We hypothesized that this subset of TNBC has distinct transcriptional features that contribute to poor prognosis.

Approach: To evaluate transcriptional signatures associated with this 'proliferation paradox,' we identified 17 study cohorts of TNBC treated with neoadjuvant chemotherapy (NAC) that reported receptor status, pathologic response, and had expression data from biopsies obtained prior to NAC (n=446). In 6 studies, distant metastasis-free survival (DMFS) data was available for 235 patients with a median follow-up of 31.2 months. We calculated scores for 135 published gene expression signatures for each tumor and evaluated the association with response to chemotherapy and DMFS.

Results: Using recursive partitioning to develop a model of response using a training set (n=340), six of the 135 expression signatures stratify primary tumors into four groups based on signatures of proliferation, BRCA1 mutation, immune, luminal, Ras, and PI3K phenotypes (Table 1.). Response to NAC ranged from 11% to 61% pCR/RCB-I and results were highly concordant when applied to a validation set (n = 106, p = 0.006). The group that was highly proliferative but chemoresistant ('resistant' group) had a distinct transcriptional profile, including lower 'BRCA-ness' and DNA damage expression signatures with higher Ras and stem cell signatures. The 'resistant' group had the poorest DMFS (HR 2.48 [1.52-4.06]; log-rank p=0.002) and this poor survival was validated among chemotherapy-treated TNBCs in a separate dataset, METABRIC. Analyses of only patients with residual disease after NAC demonstrated that the 'resistant' group remained poorest prognosis, with median DMFS of only 31 months from diagnosis.

Conclusions: Using a novel approach to categorize primary TNBC tumors based on six signatures, we can effectively distinguish subgroups with higher versus lower pCR rates. One specific group demonstrated high proliferation but low response to chemotherapy and particularly poor survival. This group demonstrates expression signatures implicating DNA damage repair, stemness, and Ras pathway activity as potential mediators of the phenotype. We identify specific molecular characteristics for investigation in patients within a poor prognosis subgroup of TNBC.

Table 1. Proportion Pathologic Complete Response or RCB-I and Survival Low ProlifHigh Prolif / ResistantHigh Prolif / SensitiveHigh ImmuneSignature StratificationLow GGI + High LuminalHigh GGI + Low BRCA1mut or High RasHigh GGI + High PI3K or Low RasHigh TNBC ImmunepCR/RCB-I rate: Training Set11/105 (10.5%)26/127 (20.5%)42/81 (51.9%)16/27 (59.3%)pCR/RCB-I rate: Validation Set3/23 (13.0%)11/45 (24.4%)13/29 (44.8%)6/9 (66.7%)pCR/RCB-I rate: TOTAL14/128 (10.9%)37/172 (21.5%)55/110 (50.0%)22/36 (61.1%)Overall Survival (n=235)Hazard Ratio (95% CI)1.62 (0.99-2.64)2.48 (1.52-4.06)(ref.)0.47 (0.29-0.77)Signatures GGI (Sotiriou, JNCI 2006); Luminal (Lim, Nat Med 2009); BRCA1 mutation (van't Veer, Nature 2002); Ras (Pratilas, PNAS 2009); PI3K (Gatza, PNAS 2010), TNBC Immune (Lehmann, JCI 2011)

Citation Format: Stover DG, Selfors LM, Winer EP, Partridge AH, Barry WT. Integrated transcriptional analysis of the triple negative 'proliferation paradox': High proliferation, chemosensitivity, and poor prognosis [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 P1-07-05.