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Metastatic breast cancer remains one of the leading causes of global cancer incidence in women, despite the benefit of immune checkpoint inhibitors (ICIs) in managing various cancers and improving patient quality of life. Metastatic breast cancer is characterized by extensive infiltration of the tumor microenvironment (TME) with immunosuppressive cells, such as myeloid derived suppressor cells (MDSCs), that inhibit anti-tumoral immune cells and prevent effective activation of the adaptive immune system by ICIs. Previously, our group has shown in the breast TME that epigenetic reprogramming of MDSCs by entinostat, a histone deacetylase inhibitor, decreases MDSC immunosuppressive function and enhances response to ICIs, in part mediated by altered signaling within the Signal transducer and activator of transcription 3 (STAT3) and Nuclear factor kappa B (NFκB) axis. Next, we sought to examine the effects of entinostat on MDSC reprogramming in a distant metastatic TME. Using the syngeneic NT2.5LM NeuN mouse model of metastatic breast cancer, we established spontaneous lung metastases and treated with either vehicle or entinostat (5 mg/kg by oral gavage, 5x/week) for 3 weeks. Single cell RNA sequencing (scRNAseq) of macro-dissected lung metastases revealed a large MDSC population, and unsupervised pathways analysis of the MDSC cluster showed differential regulation of the IL6-JAK-STAT3 and TNFα-signaling-via-NFκB pathways upon entinostat treatment. In line with reports of crosstalk among STAT3, NFκB, and AP-1 pathways regulating inflammation in breast cancer, we also found through scRNAseq differential expression of AP-1 subunits JunB and FOSL1 upon entinostat treatment. At the protein level, western blot analysis of isolated intratumoral MDSCs from lung metastases revealed decreased STAT3 phosphorylation upon entinostat treatment. Using J774M cells, an MDSC-like cell line, we found decreased JunB phosphorylation and decreased FOSL1 protein upon entinostat treatment. Furthermore, preliminary evaluation of imaging mass cytometry (IMC) from tumor biopsies in selected patients with metastatic breast cancer treated with entinostat during the clinical trial NCI-9844 confirmed decreased STAT3 phosphorylation in MDSCs. Taken together, we provide new evidence in the metastatic lung TME that implicates a STAT3-NFκB-AP-1 mediated mechanism leading to decreased MDSC suppression. Evaluating this mechanism in MDSCs taken directly from treated lung metastases represents the most biologically relevant mechanistic study to date, and preliminary translation of findings in patients suggests that planned studies will lead to identification of the mechanism driving response. Citation Format: Aaron G. Baugh, Edgar Gonzalez, Valerie H. Narumi, Sofi Castanon, Jesse Kreger, James Leatherman, Won Jin Ho, Ashley Cimino-Mathews, Vered Stearns, Roisin M. Connolly, Elizabeth M. Jaffee, Adam L. MacLean, Evanthia T. Roussos Torres. Entinostat's modulation of myeloid derived suppressor cells through the STAT3-NFκB-AP-1 axis decreases suppressive signaling. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5167.

Therapeutic combinations to alter immunosuppressive, solid tumor microenvironments (TME), such as in breast cancer, are essential to improve responses to immune checkpoint inhibitors (ICI). Entinostat, an oral histone deacetylase inhibitor, has been shown to improve responses to ICIs in various tumor models with immunosuppressive TMEs. The precise and comprehensive alterations to the TME induced by entinostat remain unknown. Here, we employed single-cell RNA sequencing on HER2-overexpressing breast tumors from mice treated with entinostat and ICIs to fully characterize changes across multiple cell types within the TME. This analysis demonstrates that treatment with entinostat induced a shift from a protumor to an antitumor TME signature, characterized predominantly by changes in myeloid cells. We confirmed myeloid-derived suppressor cells (MDSC) within entinostat-treated tumors associated with a less suppressive granulocytic (G)-MDSC phenotype and exhibited altered suppressive signaling that involved the NFκB and STAT3 pathways. In addition to MDSCs, tumor-associated macrophages were epigenetically reprogrammed from a protumor M2-like phenotype toward an antitumor M1-like phenotype, which may be contributing to a more sensitized TME. Overall, our in-depth analysis suggests that entinostat-induced changes on multiple myeloid cell types reduce immunosuppression and increase antitumor responses, which, in turn, improve sensitivity to ICIs. Sensitization of the TME by entinostat could ultimately broaden the population of patients with breast cancer who could benefit from ICIs.

Background: Cancer Trials Ireland (CTI) is the national cooperative group in Ireland. The SARS-CoV-2 pandemic led to significant ongoing disruptive change in healthcare from March 2020 to the present day. Its impact and legacy on a national clinical trials organisation was assessed. Methods: A review was conducted of prospectively acquired communications, team logs and time sheets, trial activation, closure and accrual, for the period 2019 to September 2021. An online survey of the impact of the pandemic on clinical investigators and of clinical trials units was performed. A National Cancer Retreat was organised on 21 May 2021 to identify and address pandemic related disruption and develop adaptive strategies. Results: In the weeks after the pandemic was declared, remote working was initiated by all central office staff. Nationally, clinical trial accrual fell by 54% compared to the same period in 2019, radiotherapy trial accrual by 90%, and translational studies by 36%. Staff reassignment of research nurse staff occurred in 60% of units, trial monitoring was reduced in 42%, and trial initiations fell by 67%. Extreme fluctuations in monitoring hours were noted paralleling lockdown measures. Significant impact on all clinical trials units was noted including staff reassignments, reduced access to diagnostic imaging and reduced institutional supports. Remote clinic visits and remote monitoring was widely adopted. The National Cancer Retreat identified flexibility in trial conduct, staff recruitment and retention, the need for harmonisation of processes, and research staff support in the context of remote working as priorities. Conclusion: The pandemic has had a significant ongoing negative impact on cancer clinical trial activity in Ireland. Adaptive strategies including trial flexibility, expanded telehealth and remote monitoring, harmonisation of processes and staff support have been identified as priorities to ameliorate this impact, and develop a more sustainable clinical trial ecosystem.

Purpose: Patients with triple-negative breast cancer (TNBC) with homologous recombination deficient tumors achieve significantly higher pathologic complete response (pCR) rates when treated with neoadjuvant platinum-based therapy. Tumor-infiltrating lymphocytes (TIL) are prognostic and predictive of chemotherapy benefit in early stage TNBC. The relationship between TILs, BRCA1/2 mutation status, and homologous recombination deficiency (HRD) status in TNBC remains unclear. Experimental Design: We performed a pooled analysis of five phase II studies that included patients with TNBC treated with neoadjuvant platinum-based chemotherapy to evaluate the association of TILs with HRD status (Myriad Genetics) and tumor BRCA1/2 mutation status. Furthermore, the relationship between pathologic response assessed using the residual cancer burden (RCB) index and HRD status with adjustment for TILs was evaluated. Results: Among 161 patients, stromal TIL (sTIL) density was not significantly associated with HRD status (P = 0.107) or tumor BRCA1/2 mutation status (P = 0.391). In multivariate analyses, sTIL density [OR, 1.23; 95% confidence interval (CI), 0.94–1.61; P = 0.139] was not associated with pCR, but was associated with RCB 0/I status (OR 1.62; 95% CI, 1.20–2.28; P = 0.001). HRD was significantly associated with both pCR (OR 12.09; 95% CI, 4.11–44.29; P = 7.82 × 10−7) and RCB 0/I (OR 10.22; 95% CI, 4.11–28.75; P = 1.09 × 10−7) in these models. Conclusions: In patients with TNBC treated with neoadjuvant platinum-based therapy, TIL density was not significantly associated with either tumor BRCA1/2 mutation status or HRD status. In this pooled analysis, HRD and sTIL density were independently associated with treatment response, with HRD status being the strongest predictor.

There are disparities in the availability of systemic anticancer therapies (SACTs) globally. We set out to investigate the cost and reimbursement of SACTs in the United Kingdom (UK) and the Republic of Ireland (ROI) in conjunction with efficacy and licensing authority decisions in the United States (US) and the European Union (EU).We sought data pertaining to licensing in the EU, reimbursement in ROI/UK and cost/efficacy of SACTs licensed by the Food and Drug Administration (FDA) between January 2015 and May 2021. Independent samples t tests, chi-square test and Pearson's correlation were used for statistical analysis.We identified that the majority of FDA-approved regimens are licensed by the European Medicines Agency (EMA) (n = 91, 67.9%). However, only a minority of these are currently reimbursed in the UK (n = 60, 45%) or the ROI (n = 28, 21%) as of the 1Our study highlights that many licensed systemic anticancer treatments are not currently reimbursed in ROI/UK. The high cost of these medicines is independent of the presence of an OS benefit. Collaboration between regulatory agencies, governments and industry partners is needed to ensure health expenditure is directed towards the most effective treatments.

PURPOSE Endocrine therapy resistance in advanced breast cancer remains a significant clinical problem that may be overcome with the use of histone deacetylase inhibitors such as entinostat. The ENCORE301 phase II study reported improvement in progression-free survival (PFS) and overall survival (OS) with the addition of entinostat to the steroidal aromatase inhibitor (AI) exemestane in advanced hormone receptor (HR)–positive, human epidermal growth factor receptor 2 (HER2)–negative breast cancer. PATIENTS AND METHODS E2112 is a multicenter, randomized, double-blind, placebo-controlled phase III study that enrolled men or women with advanced HR-positive, HER2-negative breast cancer whose disease progressed after nonsteroidal AI. Participants were randomly assigned to exemestane 25 mg by mouth once daily and entinostat (EE) or placebo (EP) 5 mg by mouth once weekly. Primary end points were PFS by central review and OS. Secondary end points included safety, objective response rate, and lysine acetylation change in peripheral blood mononuclear cells between baseline and cycle 1 day 15. RESULTS Six hundred eight patients were randomly assigned during March 2014-October 2018. Median age was 63 years (range 29-91), 60% had visceral disease, and 84% had progressed after nonsteroidal AI in metastatic setting. Previous treatments included chemotherapy (60%), fulvestrant (30%), and cyclin-dependent kinase inhibitor (35%). Most common grade 3 and 4 adverse events in the EE arm included neutropenia (20%), hypophosphatemia (14%), anemia (8%), leukopenia (6%), fatigue (4%), diarrhea (4%), and thrombocytopenia (3%). Median PFS was 3.3 months (EE) versus 3.1 months (EP; hazard ratio = 0.87; 95% CI, 0.67 to 1.13; P = .30). Median OS was 23.4 months (EE) versus 21.7 months (EP; hazard ratio = 0.99; 95% CI, 0.82 to 1.21; P = .94). Objective response rate was 5.8% (EE) and 5.6% (EP). Pharmacodynamic analysis confirmed target inhibition in entinostat-treated patients. CONCLUSION The combination of exemestane and entinostat did not improve survival in AI-resistant advanced HR-positive, HER2-negative breast cancer.

PURPOSE Predictive biomarkers to identify patients with human epidermal growth factor receptor 2 (HER2)–positive breast cancer who may benefit from targeted therapy alone are required. We hypothesized that early measurements of tumor maximum standardized uptake values corrected for lean body mass (SULmax) on [18F]fluorodeoxyglucose positron emission tomography/computed tomography would predict pathologic complete response (pCR) to neoadjuvant pertuzumab and trastuzumab (PT). PATIENTS AND METHODS Patients with stage II/III, estrogen receptor–negative, HER2-positive breast cancer received four cycles of neoadjuvant PT. [18F]Fluorodeoxyglucose positron emission tomography/computed tomography was performed at baseline and 15 days after PT initiation (C1D15). Eighty evaluable patients were required to test the null hypothesis that the area under the curve of percentage of change in SULmax by C1D15 predicting pCR is less than or equal to 0.65, with a one-sided type I error rate of 10%. RESULTS Eighty-eight women were enrolled (83 evaluable), and 85% (75 of 88) completed all four cycles of PT. pCR after PT alone was 34%. Receiver operating characteristic analysis yielded an area under the curve of 0.76 (90% CI, 0.67 to 0.85), which rejected the null hypothesis. Between patients who obtained pCR versus not, a significant difference in median percent reduction in SULmax by C1D15 was observed (63.8% v 33.5%; P < .001), an SULmax reduction greater than or equal to 40% was more prevalent (86% v 46%; P < .001; negative predictive value, 88%; positive predictive value, 49%), and a significant difference in median C1D15 SULmax (1.6 v 3.9; P < .001) and higher proportion of C1D15 SULmax less than or equal to 3 (93% v 38%; P < .001; negative predictive value, 94%; positive predictive value, 55%) were observed. CONCLUSION Early changes in SULmax predict response to four cycles of PT in estrogen receptor–negative, HER2-positive breast cancer. Once optimized, this quantitative imaging strategy may facilitate a more tailored approach to therapy in this setting.

e20542 Background: The COVID-19 pandemic has contributed to lower hospital admissions and higher mortalities associated with chronic conditions such as cancer and cardiovascular diseases. The Rapid Access Lung Clinic (RALC), established in 2009 for immediate assessment of individuals at risk of lung cancer, has experienced reduced functioning particularly during the pandemic peaks in Ireland. Therefore, we undertook a retrospective chart review of the 2019-2021 referrals and attendances at the Cork University Hospital (CUH) RALC to determine the impact of COVID-19 on this pathway. Methods: The medical charts of patients referred to CUH RALC from 03/2019 to 02/2020 (period I), and from 03/2020 to 02/2021 (period II), were reviewed after ethical approval was obtained. Clinicodemographic characteristics including age, sex, and hometown were extracted. Average time to acquire the first CT scan, consultation at RALC, and receiving a diagnosis of cancer were calculated using the date of referral and compared between periods I and II using the t-test. Frequency and the stages of cancer diagnosis in periods I and II were compared using a Chi-squared test. Progression-free and overall survivals were measured from diagnosis date until 09/2020 for period I and 09/2021 for period II. Results: Of the 1192 medical charts reviewed; 687 patients in period I and 505 patients in period II were referred to RALC; indicating a 26.5% reduction in the number of referrals during the first year of the pandemic. Average monthly referrals (p = 0.008) and reviews (p = 0.017) were significantly lower in period II compared to period I and corresponded with the COVID-19 peaks in 04/2020 and 01/2021 in Ireland. However, no significant difference was seen in the length of time from referral to review at RALC (p = 0.11). There were 33% fewer post-referral CT scans performed (p = 0.032) and shorter wait times from referral to CT scan in period II (p = 0.001). The frequency of cancers detected did not differ between periods I and II. While there was no difference in the wait times from referral to diagnosis between periods, patients ultimately diagnosed with lung cancer in period II received surgery sooner than patients in period I (p = 0.024). Progression-free and overall survivals for patients diagnosed with lung cancer were comparable between periods I and II. Conclusions: Contrary to our hypothesis, we have shown that the COVID-19 pandemic had minimal impact on the performance of RALC. Shorter wait times for CT scan and surgery during the pandemic account for fewer hospital referrals and availability of CT scanner. Fewer referrals to RALC in period II may relate to the fewer patients attending their general practitioner (GP) and/or GPs raising the thresholds for referrals to RALC during the pandemic. Ultimately, a national evaluation will be required to fully determine the impact of this pandemic on lung cancer diagnosis, management, and outcomes in Ireland.

525 Background: Homologous recombination deficiency (HRD) status can be used to identify patients who are eligible for treatment with DNA damaging agents. Using a 3-biomarker Genomic Instability Score (GIS) threshold of ≥42, studies have previously examined the association between HRD status and outcomes in patients with triple negative breast cancer (TNBC). However, evidence suggests that a GIS threshold of ≥33 may be more appropriate. Here, we conducted an exploratory analysis evaluating the ability of ≥33 and ≥42 GIS thresholds to predict response to platinum-based treatment in patients with TNBC. Methods: Patients across 5 cohorts (TBCRC0301, TBCRC0082, NCT013725793, PrECOG 01054, combined cisplatin cohort4) were included in this analysis if they had a primary TNBC diagnosis, received neoadjuvant platinum-based treatment, had a valid GIS, and had known pathologic complete response (pCR) status. GIS was determined by a combination of loss of heterozygosity, telomeric-allelic imbalance, and large-scale state transitions.4,5 BRCA mutation status was defined by loss of function resulting from a pathogenic variant in BRCA1 or BRCA2. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated by comparing binary threshold status and binary pCR status. Results: A total of 204 tumors (158 BRCAwt; 33 BRCAm; 13 unknown) were included; pCR to platinum-based treatment occurred in 55 cases (39 BRCAwt; 14 BRCAm; 2 unknown). Sensitivity, specificity, PPV, and NPV were comparable between the ≥33 and ≥42 GIS thresholds, with the ≥33 threshold producing higher sensitivity values. This was true when thresholds were applied to all samples and to BRCAwt samples only (Table). Among patients who achieved pCR in response to platinum-based treatment, 5.5% of patients in the full cohort and 7.7% of those in the BRCAwt cohort had a GIS between 33-41. Conclusions: To ensure that the majority of patients likely to benefit from treatment are identified, a GIS of ≥33 may be the most appropriate threshold to predict response to platinum-based treatment in patients with TNBC; however, a prospective trial will be needed to confirm these findings. Additional studies will be important to determine whether this threshold may be appropriate to determine eligibility for other DNA-damaging agents such as PARP inhibitors. 1. Ann Oncol. 2020;31(11):1518-25 2. J Nucl Med. 2015;56(1):31-7. 3. Breast Cancer Res Treat. 2015;151(3):629-38. 4. Clin Cancer Res. 2016;22(15):3764-73. 5. Breast Cancer Res Treat. 2014;16(6):1-9. [Table: see text]

Immune-checkpoint inhibition (ICI) has revolutionized treatment in cancers that are naturally immunogenic by enabling infiltration of T cells into the tumor microenvironment (TME) and promoting cytotoxic signaling pathways. Tumors possessing complex immunosuppressive TMEs such as breast and pancreatic cancers present unique therapeutic obstacles as response rates to ICI remain low. Such tumors often recruit myeloid-derived suppressor cells (MDSCs), whose functioning prohibits both T-cell activation and infiltration. We attempted to sensitize these tumors to ICI using epigenetic modulation to target MDSC trafficking and function to foster a less immunosuppressive TME. We showed that combining a histone deacetylase inhibitor, entinostat (ENT), with anti–PD-1, anti–CTLA-4, or both significantly improved tumor-free survival in both the HER2/neu transgenic breast cancer and the Panc02 metastatic pancreatic cancer mouse models. Using flow cytometry, gene-expression profiling, and ex vivo functional assays, we characterized populations of tumor-infiltrating lymphocytes (TILs) and MDSCs, as well as their functional capabilities. We showed that addition of ENT to checkpoint inhibition led to significantly decreased suppression by granulocytic MDSCs in the TME of both tumor types. We also demonstrated an increase in activated granzyme-B–producing CD8+ T effector cells in mice treated with combination therapy. Gene-expression profiling of both MDSCs and TILs identified significant changes in immune-related pathways. In summary, addition of ENT to ICI significantly altered infiltration and function of innate immune cells, allowing for a more robust adaptive immune response. These findings provide a rationale for combination therapy in patients with immune-resistant tumors, including breast and pancreatic cancers.

Atezolizumab with chemotherapy has shown improved progression-free and overall survival in patients with metastatic PD-L1 positive triple negative breast cancer (TNBC). Atezolizumab with anthracycline- and taxane-based neoadjuvant chemotherapy has also shown increased pathological complete response (pCR) rates in early TNBC. This trial evaluated neoadjuvant carboplatin and paclitaxel with or without atezolizumab in patients with clinical stages II-III TNBC. The co-primary objectives were to evaluate if chemotherapy and atezolizumab increase pCR rate and tumor infiltrating lymphocyte (TIL) percentage compared to chemotherapy alone in the mITT population. Sixty-seven patients (ages 25-78 years; median, 52 years) were randomly assigned - 22 patients to Arm A, and 45 to Arm B. Median follow up was 6.6 months. In the modified intent to treat population (all patients evaluable for the primary endpoints who received at least one dose of combination therapy), the pCR rate was 18.8% (95% CI 4.0-45.6%) in Arm A, and 55.6% (95% CI 40.0-70.4%) in Arm B (estimated treatment difference: 36.8%, 95% CI 8.5-56.6%; p = 0.018). Grade 3 or higher treatment-related adverse events occurred in 62.5% of patients in Arm A, and 57.8% of patients in Arm B. One patient in Arm B died from recurrent disease during the follow-up period. TIL percentage increased slightly from baseline to cycle 1 in both Arm A (mean ± SD: 0.6% ± 21.0%) and Arm B (5.7% ± 15.8%) (p = 0.36). Patients with pCR had higher median TIL percentages (24.8%) than those with non-pCR (14.2%) (p = 0.02). Although subgroup analyses were limited by the small sample size, PD-L1-positive patients treated with chemotherapy and atezolizumab had a pCR rate of 75% (12/16). The addition of atezolizumab to neoadjuvant carboplatin and paclitaxel resulted in a statistically significant and clinically relevant increased pCR rate in patients with clinical stages II and III TNBC. (Funded by National Cancer Institute).

Purpose: Epigenetic modulators improve immune checkpoint inhibitor (ICI) efficacy and increase CD8+ effector:FoxP3+ regulatory T cell ratios in preclinical models. We conducted a multicenter phase I clinical trial combining the histone deacetylase inhibitor entinostat with nivolumab ± ipilimumab in advanced solid tumors. Patients and Methods: Patients received an entinostat run-in (5 mg, weekly × 2) prior to the addition of ICIs. Dose escalation followed a modified 3+3 design [dose level (DL)1/2: entinostat + nivolumab; DL 3/4: entinostat + nivolumab + ipilimumab]. Blood and tissue samples were collected at baseline, after entinostat run-in, and after 8 weeks of combination therapy. Primary endpoints included safety and tolerability, and the recommended phase II dose (RP2D). Secondary endpoints included antitumor activity and change in tumor CD8/FoxP3 ratio pre- and post-therapy. Results: Thirty-three patients were treated across four dose levels. Treatment-related adverse events (AE) included fatigue (65%), nausea (41%), anemia (38%), diarrhea (26%), and anorexia (26%). Grade 3/4 AEs included fatigue (n = 7, 21%), anemia (n = 9, 27%), and neutropenia (n = 4, 12%). The RP2D was 3 mg entinostat weekly, 3 mg/kg every 2 weeks nivolumab, and 1 mg/kg every 6 weeks ipilimumab (max four doses). The objective response rate by RECIST 1.1 was 16%, including a complete response in triple-negative breast cancer. A statistically significant increase in CD8/FoxP3 ratio was seen following the addition of ICIs to entinostat, but not post-entinostat alone. Conclusions: The combination of entinostat with nivolumab ± ipilimumab was safe and tolerable with expected rates of immune-related AEs. Preliminary evidence of both clinical efficacy and immune modulation supports further investigation.

PURPOSE Predictive biomarkers to identify patients with human epidermal growth factor receptor 2 (HER2)–positive breast cancer who may benefit from targeted therapy alone are required. We hypothesized that early measurements of tumor maximum standardized uptake value corrected for lean body mass (SULmax) on 18F-labeled fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) would predict pathologic complete response (pCR) to pertuzumab and trastuzumab (PT). PATIENTS AND METHODS Patients with stage II or III, estrogen receptor–negative, HER2-positive breast cancer received four cycles of neoadjuvant PT. 18F-labeled fluorodeoxyglucose positron emission tomography-computed tomography was performed at baseline and 15 days after PT initiation (C1D15). Eighty evaluable patients were required to test the null hypothesis that the area under the curve of percent change in SULmax by C1D15 predicting pCR is ≤ 0.65, with a one-sided type I error rate of 10%. RESULTS Eighty-eight women were enrolled (83 evaluable), and 85% (75 of 88) completed all four cycles of PT. pCR after PT alone was 22%. Receiver operator characteristic analysis of percent change in SULmax by C1D15 yielded an area under the curve of 0.72 (80% CI, 0.64 to 0.80; one-sided P = .12), which did not reject the null hypothesis. However, between patients who obtained pCR and who did not, a significant difference in median percent reduction in SULmax by C1D15 was observed (63.8% v 41.8%; P = .004) and SULmax reduction ≥ 40% was more prevalent (83% v 52%; P = .03; positive predictive value, 31%). Participants not obtaining a 40% reduction in SULmax by C1D15 were unlikely to obtain pCR (negative predictive value, 91%). CONCLUSION Although the primary objective was not met, early changes in SULmax predict response to PT in estrogen receptor–negative and HER2-positive breast cancer. Once optimized, this quantitative imaging strategy may facilitate tailoring of therapy in this setting.

Purpose: Romidepsin dosing recommendations for patients with malignancy and varying degrees of hepatic dysfunction was lacking at the time of regulatory approval for T-cell lymphoma. We conducted a multicenter phase I clinical trial (ETCTN-9008) via the NCI Organ Dysfunction Working Group to investigate safety, first cycle MTD, and pharmacokinetic profile of romidepsin in this setting. Patients and Methods: Patients with select advanced solid tumors or hematologic malignancies were stratified according to hepatic function. Romidepsin was administered intravenously on days 1, 8, and 15 of a 28-day cycle and escalation followed a 3 + 3 design in moderate and severe impairment cohorts. Blood samples for detailed pharmacokinetic analyses were collected after the first dose. Results: Thirty-one patients received one dose of romidepsin and were evaluable for pharmacokinetic analyses in normal (n = 12), mild (n = 8), moderate (n = 5), and severe (n = 6) cohorts. Adverse events across cohorts were similar, and dose-limiting toxicity occurred in two patients (mild and severe impairment cohorts). The MTD was not determined because the geometric mean AUC values of romidepsin in moderate (7 mg/m2) and severe (5 mg/m2) impairment cohort were 114% and 116% of the normal cohort (14 mg/m2). Conclusions: Data from the ETCTN-9008 trial led to changes in the romidepsin labeling to reflect starting dose adjustment for patients with cancer and moderate and severe hepatic impairment, with no adjustment for mild hepatic impairment.

HER2-positive early breast cancer has been revolutionized by the development of HER2-directed therapy, which has significantly reduced breast cancer recurrence risk and improved overall survival. Here, we review the available treatment options for this patient population and discuss how we might individualize therapy in the future to optimize the balance of efficacy and toxicity. The addition of pertuzumab to a trastuzumab-based adjuvant regimen improves pathologic complete response rates and invasive disease-free survival (DFS). Addition of neratinib for patients with high-risk disease also contributes to improved DFS. Current data supports use of dual HER2-directed therapy in combination with chemotherapy, as well as extended HER2-directed therapy (beyond 1 year), in those with high-risk HER2-positive early breast cancer. Ongoing studies aim to identify biomarkers of response and resistance to standard approaches, as well as identify those who might benefit from a chemotherapy-free treatment paradigm.

BACKGROUND Human epidermal growth factor receptor 2 (HER2)-targeted therapies are highly effective at preventing breast cancer recurrence but are associated with cardiotoxicity in some patients, and minimal data are available regarding racial disparities in the incidence of this toxicity. The authors conducted a retrospective study to analyze the association of black or white race with treatment-induced cardiotoxicity and incomplete therapy among patients with HER2-positive early breast cancer. METHODS Women with HER2-positive, stage I through III breast cancer who initiated (neo)adjuvant HER2-targeted therapy (trastuzumab with or without pertuzumab) from January 2005 to March 2015 at the authors' institution were eligible. We analyzed differences in the incidence of cardiotoxicity (a decline in the left ventricular ejection fraction to

Endocrine therapies are effective in the treatment of hormone receptor (HR)-positive breast cancer, however, de novo or acquired treatment resistance is a significant clinical problem. A potential mechanism of resistance involves changes in gene expression secondary to epigenetic modifications, which might be reversed with the use of histone deacetylase (HDAC) inhibitors such as entinostat. The ENCORE 301 phase II randomized, placebo-controlled study demonstrated a significant improvement in progression-free survival (PFS) and overall survival (OS), with the addition of entinostat to exemestane in patients with HR-positive advanced breast cancer with disease progression after prior non-steroidal aromatase inhibitor (AI). These results prompted the development of E2112, a phase III registration trial which is investigating entinostat/placebo in combination with exemestane in patients with locally advanced or metastatic breast cancer who have experienced disease progression after a non-steroidal AI. E2112 aims to validate the preclinical and clinical findings supporting the role of HDAC inhibitors in overcoming resistance to endocrine therapy in breast cancer, and ultimately improve outcomes for patients with advanced breast cancer.

BackgroundThe benefit of immune checkpoint inhibitors (ICIs) in patients with leptomeningeal metastases (LMM) is unknown.MethodsWe undertook a phase II trial of pembrolizumab in patients with LMM from solid tumors. Eligible patients had radiologic/cytologic LMM and Eastern Cooperative Oncology Group performance status 0–1. Pembrolizumab was administered intravenously at 200 mg q3W until disease progression/unacceptable toxicity. The primary endpoint was central nervous system (CNS) response after four cycles, defined radiologically/cytologically/clinically. Serial cerebrospinal fluid (CSF) was assessed for tumor-derived DNA (t-DNA) aneuploidy and cytokines.ResultsThirteen of a planned 16 patients were treated between April 2017 and December 2019. The study closed early for poor accrual. Median age was 57 years (range: 22–79). Sixty-two percent of patients had tumors not traditionally ICI-responsive (hormone-receptor (HR)-positive breast carcinoma=39%; high-grade glioma=23%), while 38% had ICI-responsive tumors (non-small cell lung cancer (NSCLC)=23%, head and neck carcinoma=8%, cutaneous squamous carcinoma (CSC)=8%). CNS response was observed in 38% of patients at 12 weeks (95% CI 13.9% to 68.4%) by pre-defined criteria and LM-RANO, and 2 achieved durable complete responses (CSC=1, overall survival (OS) 3+ years; NSCLC=1, OS 9 months). Median CNS progression-free survival and OS was 2.9 months (95% CI 1.3 to NR) and 4.9 months (95% CI 3.7 to NR), respectively. Grade 3+ treatment-related adverse events occurred in 15% of patients. Sensitivity for LMM detection by t-DNA and cytopathology was 84.6% (95% CI 54.6% to 98.1%) and 53.9% (95% CI 25.1% to 80.8%), respectively. Pre-therapy and on-therapy CSF cytokine analysis demonstrated complete responders clustered together.ConclusionsPembrolizumab conferred a 38% CNS response rate in patients with LMM, a tolerable safety profile, and deep responses in selected patients with ICI-responsive tumors. CSF t-DNA may be sensitive for LMM detection, and immunologic subsets of CNS response warrant further study.Trial registration numberNCT03091478

Purpose: Although most human cancers display a single histology, there are unusual cases where two or more distinct tissue types present within a primary tumor. One such example is metaplastic breast carcinoma, a rare but aggressive cancer with a heterogeneous histology, including squamous, chondroid, and spindle cells. Metaplastic carcinomas often contain an admixed conventional ductal invasive or in situ mammary carcinoma component, and are typically triple-negative for estrogen receptor, progesterone receptor, and HER-2 amplification/overexpression. An unanswered question is the origin of metaplastic breast cancers. While they may arise independently from their ductal components, their close juxtaposition favors a model that postulates a shared origin, either as two derivatives from the same primary cancer or one histology as an outgrowth of the other. Understanding the mechanism of development of these tumors may inform clinical decisions. Experimental Design: We performed exome sequencing for paired metaplastic and adjacent conventional invasive ductal carcinomas in 8 patients and created a pipeline to identify somatic variants and predict their functional impact, without having normal tissue. We then determined the genetic relationships between the histologically distinct compartments. Results: In each case, the tumor components have nearly identical landscapes of somatic mutation, implying that the differing histologies do not derive from genetic clonal divergence. Conclusions: A shared origin for tumors with differing histologies suggests that epigenetic or noncoding changes may mediate the metaplastic phenotype and that alternative therapeutic approaches, including epigenetic therapies, may be required for metaplastic breast cancers. Clin Cancer Res; 23(16); 4875–84. ©2017 AACR.

Entinostat is a synthetic benzamide derivative histone deacetylase (HDAC) inhibitor, which potently and selectively inhibits class I and IV HDAC enzymes. This action promotes histone hyperacetylation and transcriptional activation of specific genes, with subsequent inhibition of cell proliferation, terminal differentiation and apoptosis. This oral HDAC inhibitor has been evaluated in Phase I and II trials in patients with advanced malignancies, and is in general well tolerated. Entinostat does not currently have regulatory approval for clinical use; however promising preclinical and clinical data exist in hormone-resistant breast cancer. An ECOG-ACRIN Phase III registration study is ongoing in advanced breast cancer (E2112, NCT02115282) and aims to confirm the overall survival advantage observed with the combination of exemestane and entinostat/placebo in the Phase II setting (ENCORE301 trial). This article provides an overview of the chemistry, pharmacokinetics/pharmacodynamics and available clinical data for entinostat with a focus on advanced breast cancer.

Purpose: We initiated a clinical trial to determine the proportion of breast cancer survivors achieving ≥5% weight loss using a remotely delivered weight loss intervention (POWER-remote) or a self-directed approach, and to determine the effects of the intervention on biomarkers of cancer risk including metabolism, inflammation, and telomere length. Experimental Design: Women with stage 0–III breast cancer, who completed local therapy and chemotherapy, with a body mass index ≥25 kg/m2 were randomized to a 12-month intervention (POWER-remote) versus a self-directed approach. The primary objective was to determine the number of women who achieved at least 5% weight loss at 6 months. We assessed baseline and 6-month change in a panel of adipocytokines (adiponectin, leptin, resistin, HGF, NGF, PAI1, TNFα, MCP1, IL1β, IL6, and IL8), metabolic factors (insulin, glucose, lipids, hs-CRP), and telomere length in peripheral blood mononuclear cells. Results: From 2013 to 2015, 96 women were enrolled, and 87 were evaluable for the primary analysis; 45 to POWER-remote and 42 to self-directed. At 6 months, 51% of women randomized to POWER-remote lost ≥5% of their baseline body weight, compared with 12% in the self-directed arm [OR, 7.9; 95% confidence interval (CI), 2.6–23.9; P = 0.0003]; proportion were similar at 12 months (51% vs 17%, respectively, P = 0.003). Weight loss correlated with significant decreases in leptin, and favorable modulation of inflammatory cytokines and lipid profiles. There was no significant change in telomere length at 6 months. Conclusions: A remotely delivered weight loss intervention resulted in significant weight loss in breast cancer survivors, and favorable effects on several biomarkers.

PURPOSE: Family is often overlooked in cancer care. We developed a patient-family agenda setting intervention to engage family in cancer care communication. METHODS: We conducted a pilot randomized controlled trial (NCT03283553) of patients on active treatment for breast cancer and their family “care partner.” Intervention dyads (n=69) completed a self-administered checklist to clarify care partner roles, establish a shared visit agenda, and facilitate MyChart patient portal access. Control dyads (n=63) received usual care. We assessed intervention acceptability and initial effects from post-visit surveys and MyChart utilization at 6 weeks. RESULTS: At baseline, most patients (89.4%) but few care partners (1.5%) were registered for MyChart. Most patients (79.4%) wanted their care partner to have access to their records and 39.4% of care partners reported accessing MyChart. In completing the checklist, patients and care partners endorsed active communication roles for the care partner and identified a similar visit agenda: most (>90%) reported the checklist was easy, useful, and recommended it to others. At 6 weeks, intervention (vs control) care partners were more likely to be registered for MyChart (75.4 % vs 1.6%; p

PURPOSE Evidence-based treatments for metastatic, human epidermal growth factor receptor 2 (HER2)–positive breast cancer to the CNS are limited. We previously reported modest activity of neratinib monotherapy for HER2-positive breast cancer brain metastases. Here we report the results from additional study cohorts. PATIENTS AND METHODS Patients with measurable, progressive, HER2-positive brain metastases (92% after receiving CNS surgery and/or radiotherapy) received neratinib 240 mg orally once per day plus capecitabine 750 mg/m2 twice per day for 14 days, then 7 days off. Lapatinib-naïve (cohort 3A) and lapatinib-treated (cohort 3B) patients were enrolled. If nine or more of 35 (cohort 3A) or three or more of 25 (cohort 3B) had CNS objective response rates (ORR), the drug combination would be deemed promising. The primary end point was composite CNS ORR in each cohort separately, requiring a reduction of 50% or more in the sum of target CNS lesion volumes without progression of nontarget lesions, new lesions, escalating steroids, progressive neurologic signs or symptoms, or non-CNS progression. RESULTS Forty-nine patients enrolled in cohorts 3A (n = 37) and 3B (n = 12; cohort closed for slow accrual). In cohort 3A, the composite CNS ORR = 49% (95% CI, 32% to 66%), and the CNS ORR in cohort 3B = 33% (95% CI, 10% to 65%). Median progression-free survival was 5.5 and 3.1 months in cohorts 3A and 3B, respectively; median survival was 13.3 and 15.1 months. Diarrhea was the most common grade 3 toxicity (29% in cohorts 3A and 3B). Neratinib plus capecitabine is active against refractory, HER2-positive breast cancer brain metastases, adding additional evidence that the efficacy of HER2-directed therapy in the brain is enhanced by chemotherapy. For optimal tolerance, efforts to minimize diarrhea are warranted.

Background: Endocrine therapy resistance in advanced breast cancer remains a significant clinical problem that may be overcome with use of histone deacetylase (HDAC) inhibitors such as entinostat. The ENCORE 301 randomized phase II study reported an improvement in progression-free (PFS) and overall survival (OS) with the addition of entinostat to the steroidal aromatase inhibitor (AI) exemestane in patients with advanced hormone receptor (HR)-positive, HER2-negative breast cancer. Protein lysine acetylation in peripheral blood mononuclear cells (PBMCs) was associated with prolonged PFS in the entinostat arm. Methods: E2112 is a multicenter randomized double-blind, placebo-controlled phase III study that enrolled men or women with advanced HR-positive, HER2-negative breast cancer whose disease had progressed on a non-steroidal AI in the adjuvant or metastatic setting (NCT02115282). Study participants were also required to have an ECOG performance status 0-1 with measurable or non-measurable (limited to 20% of the study population) disease. One prior chemotherapy for metastatic disease and prior treatment with fulvestrant and a CDK4/6 inhibitor was permitted but not required. Participants received exemestane 25mg po daily and entinostat (EE)/placebo (EP) 5mg po every week. Primary endpoints were PFS (central review) and OS. One-sided type 1 error 0.025 was split between two hypothesis tests: 0.001 for PFS test and 0.024 for OS. PFS tested in the first 360 pts, 88.5% power to detect 42% reduction in the hazard of PFS failure (median PFS, 4.1 to 7.1 months); OS tested in all 600 pts, 80% power to detect 25% reduction in the hazard of death (median OS, 22 to 29.3 months). Secondary endpoints included safety, objective response rate (ORR), and changes in protein lysine acetylation status in PBMCs (CD3+ T cells, CD14+ monocytes, CD19+ B cells, pan-leukocyte marker CD45+ cells, CD56+ NK cells) between C1D1 and C1D15 (integrated biomarker). Results: A total of 608 participants were randomized between March 2014 and October 2018 (305 EE, 303 EP), 98% enrolled in USA. Characteristics were well balanced between the arms. Median age was 63 years (range, 29-91), 99% female, 95% postmenopausal, 80% white and 15% black. A majority (84%) had disease resistant to AI in the metastatic setting at study entry, 78% had measurable disease and 60% visceral disease. Prior treatments included chemotherapy (60%), fulvestrant (30%), CDK4/6 inhibitor (35%), everolimus (3%). Median prior lines of chemotherapy was 1 (range, 0-4) and endocrine therapy was 2 (range, 1-7); in adjuvant/metastatic setting. Grade 3/4 adverse events in EE arm included neutrophil count decreased (20%), hypophosphatemia (14%), anemia (8%), white blood cell decreased (6%), fatigue (4%), diarrhea (4%), and platelet count decreased (3%). At final analysis, median PFS was 3.3 months (EE) versus 3.1 months (EP) (HR=0.87, 95% CI: 0.67, 1.13, p=0.30). Median OS was 23.4 months (EE) versus 21.7 months (EP) (HR=0.99, 95% CI: 0.82, 1.21, p=0.94). ORR was 4.6% (EE) and 4.3% (EP). The median fold change in lysine acetylation in PBMCs was approximately 1.5 in EE arm, and 1 in EP arm. Participants on EE had significantly higher increase in lysine acetylation by C1D15 than patients on EP (397 paired samples available for analysis, p Conclusion: The combination of exemestane and entinostat did not improve survival in AI resistant advanced HR-positive, HER2-negative breast cancer. Pharmacodynamic analysis confirmed target inhibition in entinostat-treated patients. Citation Format: Roisin M Connolly, Fengmin Zhao, Kathy D Miller, Min-Jung Lee, Richard L Piekarz, Karen L Smith, Ursa Brown-Glaberman, Jennifer S Winn, Bryan A Faller, Adedayo A Onitilo, Mark E Burkard, George T Budd, Ellis G Levine, Melanie E Royce, Peter A Kaufman, Alexandra Thomas, Jane B Trepel, Antonio C Wolff, Joseph A Sparano. E2112: Randomized phase 3 trial of endocrine therapy plus entinostat/placebo in patients with hormone receptor-positive advanced breast cancer. A trial of the ECOG-ACRIN cancer research group [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS4-02.

Efforts to induce the differentiation of cancer stem cells through treatment with all-trans retinoic acid (ATRA) have yielded limited success, partially due to the epigenetic silencing of the retinoic acid receptor (RAR)-β. The histone deacetylase inhibitor entinostat is emerging as a promising antitumor agent when added to the standard-of-care treatment for breast cancer. However, the combination of epigenetic, cellular differentiation, and chemotherapeutic approaches against triple-negative breast cancer (TNBC) has not been investigated. In this study, we found that combined treatment of TNBC xenografts with entinostat, ATRA, and doxorubicin (EAD) resulted in significant tumor regression and restoration of epigenetically silenced RAR-β expression. Entinostat and doxorubicin treatment inhibited topoisomerase II-β (TopoII-β) and relieved TopoII-β-mediated transcriptional silencing of RAR-β. Notably, EAD was the most effective combination in inducing differentiation of breast tumor–initiating cells in vivo. Furthermore, gene expression analysis revealed that the epithelium-specific ETS transcription factor-1 (ESE-1 or ELF3), known to regulate proliferation and differentiation, enhanced cell differentiation in response to EAD triple therapy. Finally, we demonstrate that patient-derived metastatic cells also responded to treatment with EAD. Collectively, our findings strongly suggest that entinostat potentiates doxorubicin-mediated cytotoxicity and retinoid-driven differentiation to achieve significant tumor regression in TNBC. Cancer Res; 76(7); 2013–24. ©2016 AACR.

Purpose Evidence-based treatments for metastatic, human epidermal growth factor receptor 2 (HER2)–positive breast cancer in the CNS are limited. Neratinib is an irreversible inhibitor of erbB1, HER2, and erbB4, with promising activity in HER2-positive breast cancer; however, its activity in the CNS is unknown. We evaluated the efficacy of treatment with neratinib in patients with HER2-positive breast cancer brain metastases in a multicenter, phase II open-label trial. Patients and Methods Eligible patients were those with HER2-positive brain metastases (≥ 1 cm in longest dimension) who experienced progression in the CNS after one or more line of CNS-directed therapy, such as whole-brain radiotherapy, stereotactic radiosurgery, and/or surgical resection. Patients received neratinib 240 mg orally once per day, and tumors were assessed every two cycles. The primary endpoint was composite CNS objective response rate (ORR), requiring all of the following: ≥50% reduction in volumetric sum of target CNS lesions and no progression of non-target lesions, new lesions, escalating corticosteroids, progressive neurologic signs/symptoms, or non-CNS progression—the threshold for success was five of 40 responders. Results Forty patients were enrolled between February 2012 and June 2013; 78% of patients had previous whole-brain radiotherapy. Three women achieved a partial response (CNS objective response rate, 8%; 95% CI, 2% to 22%). The median number of cycles received was two (range, one to seven cycles), with a median progression-free survival of 1.9 months. Five women received six or more cycles. The most common grade ≥ 3 event was diarrhea (occurring in 21% of patients taking prespecified loperamide prophylaxis and 28% of those without prophylaxis). Patients in the study experienced a decreased quality of life over time. Conclusion Although neratinib had low activity and did not meet our threshold for success, 12.5% of patients received six or more cycles. Studies combining neratinib with chemotherapy in patients with CNS disease are ongoing.

Checkpoint inhibition is a very successful treatment strategy in cancers that are naturally immunogenic by attracting T cells into the tumor microenvironment (TME) and promoting cytotoxic signaling pathways. While this strategy has shown some efficacy in metastatic breast cancer, most breast cancers are not highly immunogenic likely due to an immunosuppressive microenvironment and a lack of tumor antigen expression and recognition. One strategy to transform the breast TME into one that is immune responsive, is to use epigenetic modulation to expose tumor antigens, promote cytokine production, thus, attracting inflammatory cells into the tumor. Epigenetic modulation also has the potential to affect activation and trafficking of myeloid derived suppressor cells (MDSCs), known to alter the immunogenicity of the TME and thus, sensitizing tumors to checkpoint modulation. We hypothesize that combinatorial therapy primes the TME by increasing immunogenicity via alteration of T cells and MDSCs. We also hypothesize that combination therapy will significantly affect immune modulatory pathways. Alterations in these could serve as a functional read out of combinatorial therapy. We are using a Her-2/neu (neu-N) transgenic mouse model which through the use of various syngeneic cell lines has the capability to inform the response of Her2 and triple negative subtypes of breast cancer to immunotherapy. This model enables us to study the efficacy of different combinations of an epigenetic agent, the histone deacetylase inhibitor entinostat, and checkpoint inhibitors anti -programmed cell death protein (PD1) and anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4) antibodies, on tumor growth and metastatic progression, and to help identify co-stimulatory and inhibitory factors regulating T cell and MDSC responses. Characterization of tumor infiltrating lymphocytes and their functional capabilities are being investigated in primary tumors and metastases using fluorescence-activated cell sorting and immunohistochemistry. Thus far, there is a significant improvement in survival and delay in tumor growth in mice inoculated with neu expressing tumor cells treated with combination anti-PD1, anti-CTLA4 and entinostat as well as with anti-PD1 in combination with Entinostat. Preliminary results also suggest that epigenetic modulation with entinostat in combination with checkpoint inhibition improves the immune response within these tumors as evidenced by increased CD8+/T-regulatory cell infiltration, and increased monocytic-MDSCs into the TME. There are ongoing survival studies testing this combination therapy in mice inoculated with triple negative breast tumor cells. Future studies will further delineate the mechanisms by which epigenetic therapy alters the function of the inflammatory response to immunotherapy. Citation Format: Evanthia T. Roussos Torres, Hayley Ma, Brian Christmas, Todd Armstrong, Elizabeth M. Jaffee. Promotion of immunogenicity using epigenetic modulation and immune checkpoint inhibition in mouse models of breast cancer [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 3667. doi:10.1158/1538-7445.AM2017-3667

TPS1102 Background: While immunostimulatory therapies have shown great success, a major challenge remains identification of mechanisms to effectively treat the majority of patients with so-called "non-inflamed" tumors lacking marked lymphocyte infiltration and PD-L1 expression. The DNA repair proficiency of a tumor may impact its potential for immune recognition and sensitivity to immune checkpoint blockade. Preclinically, PARP inhibition in HDR-deficient tumors has been shown to trigger antitumor immunity through a STING-dependent antitumor immune response. Effects of PARP inhibitors were augmented when combined with PD-1 blockade. We hypothesize that enhanced DNA damage and cell death induced by PARP inhibition in tumors with homology directed repair (HDR) deficiency will enhance adaptive anti-tumor immune responses and increase sensitivity to PD-1 axis blockers. Methods: This is a randomized, open-label phase II clinical trial exploring the PARP inhibitor olaparib either alone or in combination with the anti-PD-L1 human monoclonal antibody atezolizumab in BRCA1/2 mutated locally advanced or metastatic non-HER2-positive breast cancer. HDR deficiency is defined as the presence of deleterious BRCA 1/2 mutations. Randomization occurs in a 1:1 fashion to two arms: (1) olaparib 300 mg PO bid continuously in 21-day cycles or (2) olaparib 300 mg PO bid continuously in combination with atezolizumab 1200 IV every 3 weeks in 21-day cycles. Patients undergo baseline evaluations and pre-treatment biopsy within 2 weeks of starting therapy. Repeat biopsies are required at the time of first tumor assessment scan (6 weeks from the start of treatment) and in the event of disease progression. Correlative studies, including detailed analysis of the genomic profile and tumor immune contexture, will be performed at each biopsy time point. The primary objective is to compare progression free survival between the study arms. If progression occurs on the olaparib monotherapy arm, cross-over to the combination arm is allowed. This study began enrolling in August 2018; 47 of the planned 72 patients have been registered. Clinical trial information: NCT02849496 .

e14506 Background: Leptomeningeal metastasis (LMM) from solid tumors are rare and often refractory to standard therapies. Pembrolizumab (anti-PD-1) has efficacy in patients (pts) with brain metastases from ICI-responsive tumors, however pts with LMM are often excluded from ICI trials. We hypothesized that: 1. Pembrolizumab will lead to CNS response in LMM, and 2. Genomic/immunologic analyses on CSF could identify CNS biomarkers of response. Methods: We conducted an investigator-initiated open-label phase 2 trial of Pembrolizumab in pts with LMM from any solid tumor (NCT03091478). Eligible pts had: LMM on MRI ( > 3mm lesion) or CSF cytology, ECOG PS ≤1, and were PD-naïve. Prior RT to LMM was allowed > 3 months before study start or to non-target areas. Pembrolizumab was administered IV 200mg q3W until disease progression/unacceptable toxicity. The primary endpoint was CNS response after 12 weeks, defined as radiologic (RECIST 1.1)/cytologic/clinical response to therapy. Serial CSF samples were assessed by chromosomal copy number changes using a PCR-based approach (RealSeqS) to detect tumor-derived DNA (CSF-tDNA), and 16-color flow cytometry. Results: Thirteen of a planned 18 pts were treated 04/2017-12/2019, the study was closed early for low accrual. Median age was 58 years (22-79), 53% were female. Pts had breast carcinoma (38%, n = 5), NSCLC (23%, n = 3), high-grade glioma (23%, n = 3), HNSCC (8%, n = 1) and cutaneous squamous cell carcinoma (8%, n = 1). Median no. of prior therapies was 4 (0-8), 76% of pts had prior RT to LMM. CNS response was seen in 38% of pts (5/13: 2 = complete response (NSCLC; Squamous skin); 3 = stable disease (NSCLC, Glioma, HER2+BC) by RECIST 1.1. Treatment-related adverse events were seen in 31% (4/13) of pts, 15% (2/13) G3+ (fatigue = 1, infection = 1). CSF cytology was negative at ICI start in 6 cases, but positive by CSF-tDNA in 5/6 cases. In addition, CSF-tDNA levels can correlate with disease status. CSF flow cytometry demonstrated increase in CD45R0+ activated memory T-cells, and a shift from immature to antibody-secreting B-cells in both pts with CRs in LMM. Conclusions: Pembrolizumab was well-tolerated and demonstrated anti-tumor activity in pts with LMM in ICI-responsive tumors. Correlative analyses identified CSF-tDNA can potentially be used from diagnosis to longitudinally monitor LMM; and that T and B cell populations may be enriched in the CSF of pts whose LMM regressed. These findings support inclusion of pts with LMM in ICI studies and interrogation of CSF biomarkers. Clinical trial information: NCT03091478.

Purpose This pilot study was performed to test our ability to administer neratinib monotherapy before clinically recommended craniotomy in patients with HER2-positive metastatic breast cancer to the central nervous system, to examine neratinib’s central nervous system penetration at craniotomy, and to examine postoperative neratinib maintenance. Patients and Methods Patients with HER2-positive brain metastases undergoing clinically indicated cranial resection of a parenchymal tumor received neratinib 240 mg orally once a day for 7 to 21 days preoperatively, and resumed therapy postoperatively in 28-day cycles. Exploratory evaluations of time to disease progression, survival, and correlative tissue, cerebrospinal fluid (CSF), and blood-based analyses examining neratinib concentrations were planned. The study was registered at ClinicalTrials.gov under number NCT01494662 . Results We enrolled 5 patients between May 22, 2013, and October 18, 2016. As of March 1, 2019, patients had remained on the study protocol for 1 to 75+ postoperative cycles pf therapy. Two patients had grade 3 diarrhea. Evaluation of the CSF showed low concentrations of neratinib; nonetheless, 2 patients continued to receive therapy without disease progression for at least 13 cycles, with one on-study treatment lasting for nearly 6 years. Neratinib distribution in surgical tissue was variable for 1 patient, while specimens from 2 others did not produce conclusive results as a result of limited available samples. Conclusion Neratinib resulted in expected rates of diarrhea in this small cohort, with 2 of 5 patients receiving the study treatment for durable periods. Although logistically challenging, we were able to test a limited number of CSF- and parenchymal-based neratinib concentrations. Our findings from resected tumor tissue in one patient revealed heterogeneity in drug distribution and tumor histopathology.

Background: Immune checkpoint inhibitors (ICIs) provide benefit for immunogenic cancers that naturally attract T cell infiltration, but have limited benefit for patients with tumors that lack natural T cells in the tumor microenvironment (TME) including many breast cancers. Suboptimal and inconsistent immune responsiveness in many cancers is likely the result of a lack of tumor antigen expression and/or recognition together with multiple suppressive signals within the TME that provide a formidable barrier to T cell infiltration. Emerging data suggest that these factors can be overcome by combining epigenetic modulation that reprograms myeloid-derived suppressor cells (MDSCs) and upregulate T cell-attracting signals within the TME, with ICIs. Our paralleled preclinical and clinical trial investigates the mechanisms and efficacy of the epigenetic modulator, entinostat (ENT) to reprogram the immune suppressive cells within the TME. Methods: We conducted a multicenter phase 1 clinical trial (NCT02453620) of entinostat combined with nivolumab +/- ipilimumab in patients with advanced cancers including hormone-receptor positive or triple-negative breast cancer (TNBC). Mandatory tumor samples are being obtained pre-treatment, post-treatment with 2 weeks of entinostat, and 8 weeks post combination therapy with ICIs. We used immunohistochemical (IHC) for CD8 and FoxP3 to determine a ratio representative of immune infiltration in response to therapy. Preclinical studies utilize mouse models of breast cancer (NeuN and 4T1) and mirror the treatment scheme used in the clinical trial. We employed multiparameter flow cytometry, single cell RNA sequencing, bulk RNA sequencing of tumor specimens and patient samples to specifically interrogate the role of ENT in modulating STAT3 as a master regulator of downstream inflammatory pathways. Results: With regard to the clinical trial, out of 35 patients enrolled, 11 were diagnosed with breast cancer. We observed 4 partial responses, 2 responses in patients with breast cancer, with an ORR of 12%. We have almost completed accrual of our expansion cohort of 15 patients with advanced HER2 negative breast cancer. The primary outcomes of the clinical trial will be reported elsewhere, here we are focusing on important correlative findings which suggest a combination of ENT with ICIs alters CD8/FoxP3 ratios in certain patients. Bulk-RNA sequencing or patient samples is underway. Preliminary data from animal models obtained using scRNA-seq has begun to elucidate altered MDSC signaling pathways, and to identify gene expression changes in immune, stromal, and tumor cells following treatment with ENT. These data are also expected to identify new targets for ICI sensitization. Conclusions: Preliminary results with IHC staining suggests increased immune infiltration with combination therapy. Sequencing analysis will likely provide deeper insight into mechanisms driving response. The mechanisms of response to ICIs in patients with breast cancer have yet to be elucidated. These studies will provide the necessary scientific evidence to uncover mechanisms behind the transformation of the immunosuppressive TME and provide new targets that could improve clinical response to ICIs to maximize patient survival. The core biological themes explored will likely have a broad impact in the field of breast cancer and affect the paradigm of therapies available to patients in the clinic. These findings will help determine how treatment with ICIs will be successful to obtain durable responses for breast cancer patients. Citation Format: Evanthia T Roussos Torres, Luciane Tsukamoto Kagohara, Emily Davis, Christine Rafie, Brian Christmas, Qingfeng Zhu, Chenguang Wang, David Lim, Robert Anders, Elana Fertig, Vincent Chung, Patricia Lorusso, Adam Brufsky, Elizabeth M Jaffee, Vered Stearns, Roisin Connolly. Reprogramming the suppressive tumor microenvironment of breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-04-06.

Overexpression and cellular miss-localization of aurora kinase A (AURKA) in gastrointestinal cancers results in chromosomal instability, activation of multiple oncogenic pathways, and inhibition of pro-apoptotic signaling. Inhibition of AURKA causes mitotic delays, severe chromosome congression, and activation of p53/p73 leading to cell death. Our preclinical data showed cooperative activity with the AURKA inhibitor alisertib and platinum agents in cell lines and xenografts, and suggested an optimal treatment window. Therefore, this study was designed to determine the maximum-tolerated dose (MTD) of alisertib in combination with modified FOLFOX (mFOLFOX), as this is a standard platinum-based therapy for gastrointestinal cancers. Standard 3+3 dose escalation was used, where the starting dose of alisertib was 10 mg twice daily (Days 1–3), with leucovorin (400 mg/m(2)) and oxaliplatin (85 mg/m(2)) on Day 2 followed by continuous 46-hour 5-FU (2400 mg/m(2)) infusion on Days 2–4 in 14-day cycles. Fourteen patients with advanced gastrointestinal cancers were enrolled and two doses explored; two patients were not evaluable for dose-limiting toxicity (DLT) and replaced. Two patients experienced DLTs at 20 mg of alisertib (Grade 3 fatigue (n=2); Grade 3 nausea, vomiting, dehydration with hospitalization (n=1)). MTD was 10 mg alisertib with 85 mg/m(2) oxaliplatin and 2400 mg/m(2) 5-FU. Most frequent toxicities were nausea (57%), diarrhea, fatigue, neuropathy, and vomiting (43%), and anorexia and anemia (36%); most were Grade 1–2. One patient with colorectal cancer had a partial response of 12 evaluable patients, and four patients had stable disease. Alisertib in combination with mFOLFOX did not demonstrate unexpected side effects, but the regimen was only tolerable at the lowest dose investigated.

PURPOSE: Aromatase inhibitor-associated musculoskeletal symptoms (AIMSS) are common adverse events of AIs often leading to drug discontinuation. We initiated a prospective clinical trial to evaluate whether bisphosphonates are associated with reduced incidence of AIMSS. METHODS: In the single-arm trial, the Zoledronic Acid Prophylaxis (ZAP) trial, we compared the incidence of AIMSS against historical controls from the Exemestane and Letrozole Pharmacogenomics (ELPh) trial. Eligible women were postmenopausal with stage 0-III breast cancer planning to receive adjuvant AIs. AIMSS was assessed using the Health Assessment Questionnaire and Visual Analog Scale over 12 months in both trials. Participants in the ZAP trial received zoledronic acid prior to initiating letrozole and after 6 months; ELPh participants included in the analysis were taking letrozole but not bisphosphonates. We analyzed patient-reported outcomes (PROs) and bone density in the ZAP trial using mixed-effects linear regression models and paired t tests, respectively. RESULTS: From 2011 to 2013, 59 postmenopausal women enrolled in ZAP trial. All 59 (100%) women received baseline and 52 (88%) received 6-month zoledronic acid, and had similar characteristics to historical controls from the ELPh trial (n = 206). Cumulatively during the first year of AI, 37 and 67% of ZAP and ELPh participants reported AIMSS (p < 0.001), respectively. Within the ZAP trial, we did not observe significant changes in other PROs; however, we report improvements in bone mineral density. CONCLUSIONS: Compared to historical controls, zoledronic acid administered concomitantly with adjuvant AIs was associated with a reduced incidence of AIMSS. A randomized controlled trial is required to confirm these findings.

Epigenetic modifiers, including the histone deacetylase inhibitor vorinostat, may sensitize tumors to chemotherapy and enhance outcomes. We conducted a multicenter randomized phase II neoadjuvant trial of carboplatin and nanoparticle albumin-bound paclitaxel (CP) with vorinostat or placebo in women with stage II/III, human epidermal growth factor receptor 2 (HER2)–negative breast cancer, in which we also examined whether change in maximum standardized uptake values corrected for lean body mass (SULmax) on 18F-FDG PET predicted pathologic complete response (pCR) in breast and axillary lymph nodes. Methods: Participants were randomly assigned to 12 wk of preoperative carboplatin (area under the curve of 2, weekly) and nab-paclitaxel (100 mg/m2 weekly) with vorinostat (400 mg orally daily, days 1–3 of every 7-d period) or placebo. All patients underwent 18F-FDG PET and research biopsy at baseline and on cycle 1 day 15. The primary endpoint was the pCR rate. Secondary objectives included correlation of change in tumor SULmax on 18F-FDG PET by cycle 1 day 15 with pCR and correlation of baseline and change in Ki-67 with pCR. Results: In an intent-to-treat analysis (n = 62), overall pCR was 27.4% (vorinostat, 25.8%; placebo, 29.0%). In a pooled analysis (n = 59), we observed a significant difference in median change in SULmax 15 d after initiating preoperative therapy between those achieving pCR versus not (percentage reduction, 63.0% vs. 32.9%; P = 0.003). Patients with 50% or greater reduction in SULmax were more likely to achieve pCR, which remained statistically significant in multivariable analysis including estrogen receptor status (odds ratio, 5.1; 95% confidence interval, 1.3–22.7; P = 0.023). Differences in baseline and change in Ki-67 were not significantly different between those achieving pCR versus not. Conclusion: Preoperative CP with vorinostat or placebo is associated with similar pCR rates. Early change in SULmax on 18F-FDG PET 15 d after the initiation of preoperative therapy has potential in predicting pCR in patients with HER2-negative breast cancer. Future studies will further test 18F-FDG PET as a potential treatment-selection biomarker.

Human epidermal growth factor receptor 2 (HER2)-targeted therapies are highly effective at preventing breast cancer recurrence but are associated with cardiotoxicity in some patients, and minimal data are available regarding racial disparities in the incidence of this toxicity. The authors conducted a retrospective study to analyze the association of black or white race with treatment-induced cardiotoxicity and incomplete therapy among patients with HER2-positive early breast cancer.Women with HER2-positive, stage I through III breast cancer who initiated (neo)adjuvant HER2-targeted therapy (trastuzumab with or without pertuzumab) from January 2005 to March 2015 at the authors' institution were eligible. We analyzed differences in the incidence of cardiotoxicity (a decline in the left ventricular ejection fraction to50% AND an absolute drop in the left ventricular ejection fraction of ≥10% from baseline) and incomplete therapy (52 weeks of HER2-targeted therapy) between black and white women in univariate and multivariable analyses.The authors identified 59 black patients and 157 white patients who had a median follow-up 5.2 years. The median patient age was 53 years and was similar for black and white patients. The 1-year cardiotoxicity incidence was 12% overall (95% confidence interval [CI], 7%-16%), 24% in black women (95% CI, 12%-34%), and 7% in white women (95% CI, 3%-11%). Black patients had a significantly greater probability of incomplete therapy compared with white patients (odds ratio, 4.61; 95% CI, 1.70-13.07; P = .002). High correlation was observed between a cardiotoxicity event and incomplete therapy (96% concordance).Black patients have a higher rate of cardiotoxicity and resultant incomplete adjuvant HER2-targeted therapy than white patients. This patient population may benefit from enhanced cardiac surveillance, cardioprotective strategies, and early referral to cardiology when appropriate. Cancer 2018;124:1904-11. © 2018 American Cancer Society.

Methylated gene markers have shown promise in predicting breast cancer outcomes and treatment response. We evaluated whether baseline and changes in tissue and serum methylation levels would predict pathological complete response (pCR) in patients with HER2-negative early breast cancer undergoing preoperative chemotherapy. The TBCRC008 trial investigated pCR following 12 weeks of preoperative carboplatin and albumin-bound paclitaxel + vorinostat/placebo (n = 62). We measured methylation of a 10-gene panel by quantitative multiplex methylation-specific polymerase chain reaction and expressed results as cumulative methylation index (CMI). We evaluated association between CMI level [baseline, day 15 (D15), and change] and pCR using univariate and multivariable logistic regression models controlling for treatment and hormone receptor (HR) status, and performed exploratory subgroup analyses. In univariate analysis, one log unit increase in tissue CMI levels at D15 was associated with 40% lower chance of obtaining pCR (odds ratio, OR 0.60, 95% CI 0.37–0.97; p = 0.037). Subgroup analyses suggested a significant association between tissue D15 CMI levels and pCR in vorinostat-treated [OR 0.44 (0.20, 0.93), p = 0.03], but not placebo-treated patients. In this study investigating the predictive roles of tissue and serum CMI levels in patients with early breast cancer for the first time, we demonstrate that high D15 tissue CMI levels may predict poor response. Larger studies and improved analytical procedures to detect methylated gene markers in early stage breast cancer are needed. TBCRC008 is registered on ClinicalTrials.gov (NCT00616967).

Purpose Tumor genomic profiling for personalized oncology therapy is being widely applied in clinical practice even as it is being evaluated more formally in clinical trials. Given the complexities of genomic data and its application to clinical use, molecular tumor boards with diverse expertise can provide guidance to oncologists and patients seeking to implement personalized genetically targeted therapy in practice. Methods A multidisciplinary molecular tumor board reviewed tumor molecular profiling reports from consecutive referrals at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins over a 3-year period. The tumor board weighed evidence for actionability of genomic alterations identified by molecular profiling and provided recommendations including US Food and Drug Administration–approved drug therapy, clinical trials of matched targeted therapy, off-label use of such therapy, and additional tumor or germline genetic testing. Results One hundred fifty-five patients were reviewed. Actionable genomic alterations were identified in 132 patients (85%). Off-label therapies were recommended in 37 patients (24%). Eleven patients were treated off-label, and 13 patients were enrolled onto clinical trials of matched targeted therapies. Median progression-free survival of patients treated with matched therapies was 5 months ( 95% CI, 2.9 months to not reached), and the progression-free survival probability at 6 months was 43% (95% CI, 26% to 71%). Lack of locally available clinical trials was the major limitation on clinical actionability of tumor profiling reports. Conclusion The molecular tumor board recommended off-label targeted therapies for a quarter of all patients reviewed. Outcomes were heterogeneous, although 43% of patients receiving genomically matched therapy derived clinical benefit lasting at least 6 months. Until more data become available from precision oncology trials, molecular tumor boards can help guide appropriate use of tumor molecular testing to direct therapy.

// Huili Li 1,* , Katherine B. Chiappinelli 1,* , Angela A. Guzzetta 1,* , Hariharan Easwaran 1 , Ray-Whay Chiu Yen 1 , Rajita Vatapalli 1 , Michael J. Topper 1 , Jianjun Luo 1 , Roisin M. Connolly 1,2 , Nilofer S. Azad 1 , Vered Stearns 1,2 , Drew M. Pardoll 1 , Nancy Davidson 3 , Peter A. Jones 4 , Dennis J. Slamon 5 , Stephen B. Baylin 1 , Cynthia A. Zahnow 1 , Nita Ahuja 1,6 1 Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA 2 Breast Cancer Program, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD, USA 3 Department of Medicine, University of Pittsburgh Cancer Institute and UPMC CancerCenter, Pittsburgh, PA 4 Departments of Urology and Biochemistry and Molecular Biology, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 5 The Jonsson Comprehensive Cancer Center, University of California-Los Angeles 6 Department of Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, USA * These authors contributed equally to the work Correspondence: Nita Ahuja, email: // Cynthia A. Zahnow, email: // Keywords : Epigenetics, immune, cancers, DNA methyltransferase inhibitor, interferon, methylation, antigen processing Received : February 4, 2014 Accepted : February 16, 2014 Published : February 16, 2014 Abstract Epigenetic therapy is emerging as a potential therapy for solid tumors. To investigate its mechanism of action, we performed integrative expression and methylation analysis of 63 cancer cell lines (breast, colorectal, and ovarian) after treatment with the DNA methyltransferase inhibitor 5-azacitidine (AZA). Gene Set Enrichment Analysis demonstrated significant enrichment for immunomodulatory pathways in all three cancers (14.4-31.3%) including interferon signaling, antigen processing and presentation, and cytokines/chemokines. Strong upregulation of cancer testis antigens was also observed. An AZA IMmune gene set (AIMs) derived from the union of these immunomodulatory pathway genes classified primary tumors from all three types, into “high” and “low” AIM gene expression subsets in tumor expression data from both TCGA and GEO. Samples from selected patient biopsies showed upregulation of AIM genes after treatment with epigenetic therapy. These results point to a broad immune stimulatory role for DNA demethylating drugs in multiple cancers.

Purpose Gene expression profiling assays are frequently used to guide adjuvant chemotherapy decisions in hormone receptor–positive, lymph node–negative breast cancer. We hypothesized that the clinical value of these new tools would be more fully realized when appropriately integrated with high-quality clinicopathologic data. Hence, we developed a model that uses routine pathologic parameters to estimate Oncotype DX recurrence score (ODX RS) and independently tested its ability to predict ODX RS in clinical samples. Patients and Methods We retrospectively reviewed ordered ODX RS and pathology reports from five institutions (n = 1,113) between 2006 and 2013. We used locally performed histopathologic markers (estrogen receptor, progesterone receptor, Ki-67, human epidermal growth factor receptor 2, and Elston grade) to develop models that predict RS-based risk categories. Ordering patterns at one site were evaluated under an integrated decision-making model incorporating clinical treatment guidelines, immunohistochemistry markers, and ODX. Final locked models were independently tested (n = 472). Results Distribution of RS was similar across sites and to reported clinical practice experience and stable over time. Histopathologic markers alone determined risk category with > 95% confidence in > 55% (616 of 1,113) of cases. Application of the integrated decision model to one site indicated that the frequency of testing would not have changed overall, although ordering patterns would have changed substantially with less testing of estimated clinical risk–high or clinical risk–low cases and more testing of clinical risk–intermediate cases. In the validation set, the model correctly predicted risk category in 52.5% (248 of 472). Conclusion The proposed model accurately predicts high- and low-risk RS categories (> 25 or ≤ 25) in a majority of cases. Integrating histopathologic and molecular information into the decision-making process allows refocusing the use of new molecular tools to cases with uncertain risk.

Purpose: In breast cancer models, combination epigenetic therapy with a DNA methyltransferase inhibitor and a histone deacetylase inhibitor led to reexpression of genes encoding important therapeutic targets, including the estrogen receptor (ER). We conducted a multicenter phase II study of 5-azacitidine and entinostat in women with advanced hormone-resistant or triple-negative breast cancer (TNBC). Experimental Design: Patients received 5-azacitidine 40 mg/m2 (days 1–5, 8–10) and entinostat 7 mg (days 3, 10) on a 28-day cycle. Continuation of epigenetic therapy was offered with the addition of endocrine therapy at the time of progression [optional continuation (OC) phase]. Primary endpoint was objective response rate (ORR) in each cohort. We hypothesized that ORR would be ≥20% against null of 5% using Simon two-stage design. At least one response was required in 1 of 13 patients per cohort to continue accrual to 27 per cohort (type I error, 4%; power, 90%). Results: There was one partial response among 27 women with hormone-resistant disease (ORR = 4%; 95% CI, 0–19), and none in 13 women with TNBC. One additional partial response was observed in the OC phase in the hormone-resistant cohort (n = 12). Mandatory tumor samples were obtained pre- and posttreatment (58% paired) with either up- or downregulation of ER observed in approximately 50% of posttreatment biopsies in the hormone-resistant, but not TNBC cohort. Conclusions: Combination epigenetic therapy was well tolerated, but our primary endpoint was not met. OC phase results suggest that some women benefit from epigenetic therapy and/or reintroduction of endocrine therapy beyond progression, but further study is needed. Clin Cancer Res; 23(11); 2691–701. ©2016 AACR.

OBJECTIVES/SPECIFIC AIMS: Pembrolizumab is an anti-PD-1 immune checkpoint antibody that has demonstrated promising anti-tumor activity in patients with solid tumor malignancies, including patients with brain metastases from malignant melanoma and non-small cell lung cancer. Leptomeningeal disease (LMD) is a rare form of malignant spread to the central nervous system (CNS), that occurs in 2%–10% of patients with solid tumors, most commonly in breast cancer and non-small cell lung cancer. We propose an open-label phase II study of pembrolizumab in patients with LMD from advanced solid tumors (NCT03091478). This study aims to determine if pembrolizumab therapy can lead to a radiologic, cytologic or clinical response in the CNS, in patients with LMD. METHODS/STUDY POPULATION: Patients with pathologically confirmed advanced solid tumors, and either radiologic or cytologic evidence of LMD, will be identified at a single institution. Radiologic LMD will be defined as a >4 mm area of measurable LMD on gadolinium-enhanced MRI brain/total-spine; and cytologic LMD will be defined as the presence of malignant cells on CSF cytology. Patients will be excluded if they have: active autoimmune conditions that require immunosuppression, received radiation therapy to the only area of measurable LMD within 3 months of study enrollment, have an ECOG performance status

This genetic association study examines the prevalence of pathogenic/likely pathogenic germline variants among patients with metastatic breast cancer.

Background: While some patients with early stage endocrine receptor positive (ER+) breast cancer experience excellent prognosis, a subset of patients with more aggressive phenotypes still have a high rate of recurrence despite optimal adjuvant endocrine therapy and chemotherapy, thus novel therapies are needed for patients with high risk disease. Although immune checkpoint blockade has shown significant benefit in numerous types of cancer, initial reports demonstrate low response rates to single agent programmed cell death ligand 1 (PD-L1) inhibition in ER+ breast cancer. Inhibitors of cyclin dependent kinases (CDK) 4 and 6 in combination with endocrine therapy are highly active in breast cancer, and recently have been demonstrated to recruit immune cells, and increase PD-L1 on tumor cells in preclinical models. Increased tumor infiltrating lymphocytes (TILs) has been observed with neoadjuvant treatment with CDK4/6 inhibitors in patients with ER+ breast cancer. We thus hypothesize that the addition of palbociclib (CDK4/6 inhibitor) will improve responses to avelumab (PD-L1) inhibitor in patients with high risk ER+ breast cancer. Trial Design: Eligible participants are those stage II or III ER+HER2- breast cancer (T2N0 must have ≥grade 2, T1N+ must have at least a 1.5cm breast primary). Patients will undergo a baseline MRI and biopsy, start tamoxifen +/- palbociclib for 1 cycle (1 cycle =28 days), and then undergo a repeat MRI and biopsy. Avelumab will be added to both arms in cycle 2. Patients will be treated for 3 cycles of avelumab with tamoxifen +/- palbociclib (thus 4 cycles total, including run-in without avelumab). Patients will be treated as long as there is no evidence of progression and therapy is tolerated, and then undergo MRI and surgery. The primary objective is to determine the clinical complete response (cCR) rate by MRI. Secondary objectives include evaluation of TILs (H&E), CD8 and FOXP3 by immunohistochemistry (IHC), T cell receptor (TCR) repertoire (TCR sequencing), multiplex gene expression panel (Nanostring), and multiplex IHC. Changes in these immune biomarkers will be assessed to determine differential immunophenotypic effects of palbociclib, and correlated to cCR in each arm. The sample size of this pilot study is determined by primary analysis on the cCR rate. We hypothesize that the addition of palbociclib to tamoxifen will result in an increase rate of cCR in patients receiving avelumab. We hypothesize that the addition of avelumab will increase the response rate to palbociclib and tamoxifen by 30%. We thus estimate that a total of 40 evaluable patients (20 to each arm) will provide close to 80% power to detect a difference on cCR rates of 10% vs 40% at two-sided alpha level 10%. We will evaluate and compare cCR rates between arms by conducting Fisher's Exact test and reporting the estimated proportions together with their exact confidence intervals. Logistic regression analysis will also be conducted to explore the association between cCR and immune biomarkers. This study has received IRB approval and is open as of Summer 2018. Citation Format: Santa-Maria CA, Wang C, Cimino-Mathews A, Roussos-Torres E, Connolly RM, Wolff AC, Jaffee EM, Stearns V. IMMUNe mOdulation in early stage estrogen receptor positive breast cancer treated with neoADjuvant Avelumab, Palbociclib, and Tamoxifen: The ImmunoADAPT study (NCT03573648) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT3-02-03.

Retinoids and their naturally metabolized and synthetic products (e.g., all-trans retinoic acid, 13-cis retinoic acid, bexarotene) induce differentiation in various cell types. Retinoids exert their actions mainly through binding to the nuclear retinoic acid receptors (α, β, γ), which are transcriptional and homeostatic regulators with functions that are often compromised early in neoplastic transformation. The retinoids have been investigated extensively for their use in cancer prevention and treatment. Success has been achieved with their use in the treatment of subtypes of leukemia harboring chromosomal translocations. Promising results have been observed in the breast cancer prevention setting, where fenretinide prevention trials have provided a strong rationale for further investigation in young women at high risk for breast cancer. Ongoing phase III randomized trials investigating retinoids in combination with chemotherapy in non–small cell lung cancer aim to definitively characterize the role of retinoids in this tumor type. The limited treatment success observed to date in the prevention and treatment of solid tumors may relate to the frequent epigenetic silencing of RARβ. Robust evaluation of RARβ and downstream genes may permit optimized use of retinoids in the solid tumor arena. Clin Cancer Res; 19(7); 1651–9. ©2013 AACR.

Purpose: The clinical utility of next-generation sequencing (NGS) in breast cancer has not been demonstrated. We hypothesized that we could perform NGS of a new biopsy from patients with metastatic triple-negative breast cancer (TNBC) in a clinically actionable timeframe. Experimental Design: We planned to enroll 40 patients onto a prospective study, Individualized Molecular Analyses Guide Efforts (IMAGE), to evaluate the feasibility of obtaining a new biopsy of a metastatic site, perform NGS (FoundationOne), and convene a molecular tumor board to formulate treatment recommendations within 28 days. We collected blood at baseline and at time of restaging to assess cell-free circulating plasma tumor DNA (ptDNA). Results: We enrolled 26 women with metastatic TNBC who had received ≥1 line of prior chemotherapy, and 20 (77%) underwent NGS of a metastatic site biopsy. Twelve (60%) evaluable patients received treatment recommendations within 28 days of consent. The study closed after 20 patients underwent NGS, based on protocol-specified interim futility analysis. Three patients went on to receive genomically directed therapies. Twenty-four of 26 patients had genetic alterations successfully detected in ptDNA. Among 5 patients, 4 mutations found in tumor tissues were not identified in blood, and 4 mutations found in blood were not found in corresponding tumors. In 9 patients, NGS of follow-up blood samples showed 100% concordance with baseline blood samples. Conclusions: This study demonstrates challenges of performing NGS on prospective tissue biopsies in patients with metastatic TNBC within 28 days, while also highlighting the potential use of blood as a more time-efficient and less invasive method of mutational assessment. Clin Cancer Res; 23(2); 379–86. ©2016 AACR.

Objectives: Metaplastic breast carcinomas (MBCs) are rare, aggressive cancers lacking targeted therapy. Here, we review the clinicopathologic features, treatment, and outcomes of patients with MBC treated at our institution. Methods: We searched clinical and pathology databases for patients with histologically confirmed MBC from 1999 to 2012. We estimated survival probabilities using the Kaplan-Meier method and evaluated prognostic factors using Cox regression. Results: Forty-five cases were identified, including chondroid (24%), spindled (20%), sarcomatoid (16%), squamous (11%), and mixed (29%) histologic subtypes. Median tumor size was 3 cm, with 86% grade III and 69% triple-negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. Most had negative lymph nodes, and two patients had metastases at diagnosis. Six patients received neoadjuvant therapy, with one pathologic complete response. All patients underwent surgery, 60% received adjuvant radiation, and 58% had adjuvant chemotherapy. Five-year recurrence-free survival was 64%; 5-year overall survival was 69%. Tumor size, history of breast cancer, and mixed histology were associated with inferior outcomes. Conclusions: We report one of the largest single-institution series of patients with MBC. MBC is associated with a poor prognosis, despite low nodal involvement. Most patients in this series had high-grade, triple-negative tumors and were treated with optimal therapy.

Presentation of the Case A 53-year-old postmenopausal woman was found to have a new area of microcalcification at the 10 o'clock position of her right breast during a routine screening mammogram. Ultrasound-guided core biopsy revealed a grade 2 invasive ductal carcinoma, estrogen receptor (ER)+ (90%), progesterone receptor positive (20%), and human epidermal growth factor receptor (HER)-2+ (3+ by immunohistochemistry). A right breast lumpectomy and sentinel node biopsy were performed. The invasive tumor measured 0.7 cm, no lymphovascular space invasion was identified, surgical margins were uninvolved, and the sentinel lymph nodes were negative for tumor. She was evaluated postoperatively in the medical oncology clinic to discuss an adjuvant treatment strategy. The question for our colleagues is: should she be offered adjuvant chemotherapy and trastuzumab prior to adjuvant radiation and 5 years of hormonal therapy?

Purpose Preclinical studies have demonstrated that antagonism of β2-adrenergic signaling inhibits several pathways necessary for breast tumor progression and metastasis. A series of population-based observational studies were conducted to examine associations between beta blocker use and breast tumor characteristics at diagnosis or breast cancer–specific mortality. Patients and Methods Linked national cancer registry and prescription dispensing data were used to identify women with a diagnosis of stage I to IV invasive breast cancer between January 1, 2001, and December 31, 2006. Women taking propranolol (β1/β2 antagonist; n = 70) or atenolol (β1 antagonist; n = 525), in the year before breast cancer diagnosis were matched (1:2) to women not taking a beta blocker (n = 4,738). Associations between use of propranolol or atenolol and risk of local tumor invasion at diagnosis (T4 tumor), nodal or metastatic involvement at diagnosis (N2/N3/M1 tumor), and time to breast cancer–specific mortality were assessed. Results Propranolol users were significantly less likely to present with a T4 (odds ratio [OR], 0.24, 95% CI, 0.07 to 0.85) or N2/N3/M1 (OR, 0.20; 95% CI, 0.04 to 0.88) tumor compared with matched nonusers. The cumulative probability of breast cancer–specific mortality was significantly lower for propranolol users compared with matched nonusers (hazard ratio, 0.19; 95% CI, 0.06 to 0.60). There was no difference in T4 or N2/N3/M1 tumor incidence or breast cancer–specific mortality between atenolol users and matched nonusers. Conclusion The results provide evidence in humans to support preclinical observations suggesting that inhibiting the β2-adrenergic signaling pathway can reduce breast cancer progression and mortality.