A baseline tool for predicting response to peginterferon alfa-2a in HBeAg-positive patients with chronic hepatitis B

BACKGROUND

Peginterferon induces off-treatment responses in approximately one-third of patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B.

AIM

To develop an easy-to-use baseline prediction score to identify hepatitis B virus (HBV) genotype B-/C-infected HBeAg-positive Asian patients likely to respond to peginterferon alfa-2a.

METHODS

Generalised additive models, multiple logistic regression (MLR) analysis and internal validation methods were applied to data from 647 HBeAg-positive patients from China, Hong Kong and Taiwan to develop a scoring system to predict response 24 weeks after completing a 48-week course of peginterferon alfa-2a.

RESULTS

Five baseline factors (age, sex, alanine aminotransferase ratio, hepatitis B surface antigen (HBsAg) level and HBV DNA level) were retained in the final MLR for HBeAg seroconversion and used to develop a scoring system from 0 to 7. Among patients with scores of 0-1, 2-3, 4 or ≥5, HBeAg seroconversion was achieved in 6.4% (6/94), 23.0% (61/265), 36.4% (67/184) and 54.8% (57/104), respectively, and a combined response (HBeAg seroconversion plus HBV DNA <2000 IU/mL) in 5.3% (5/94), 12.8% (34/265), 25.0% (46/184) and 36.5% (38/104), respectively. Among patients with scores of 0-1, 2-3, 4 or ≥5, 57.0% (53/93), 12.3% (31/253), 3.4% (6/178) and 1.0% (1/100) had HBsAg ≥20 000 IU/mL at treatment Week 12; only 3/91 (3.3%) with HBsAg ≥20 000 IU/mL experienced a combined response at 24 weeks post-treatment (negative predictive value = 97% [88/91]).

CONCLUSION

A pre-treatment scoring system using readily available baseline characteristics identifies HBeAg-positive Asian patients likely to experience sustained HBeAg seroconversion after treatment with peginterferon alfa-2a.

High-throughput screening of a collection of known pharmacologically active small compounds for inhibitors of Salmonella invasion and intracellular replication

AIMS

The aim of this study was to screen a chemical library consisting of over 1200 pharmacologically active, already approved off-patent compounds, to determine whether any of the compounds reduced or eliminated the invasion or intracellular replication phenotypes of Salmonella enterica serovar Typhimurium (S. Typhimurium).

METHODS AND RESULTS

LacZ reporter and tissue culture-based infection assays were used to screen for compounds that significantly reduced expression of key virulence genes, and were required for the invasion or intracellular replication phenotypes of S. Typhimurium in host cells. The search lead to the discovery of four compounds that reduced invasion by between 90-100%, and two compounds that reduced intracellular replication by between 65-93% at concentrations of either 2, 10 or 50 μg ml^-1 , relative to an untreated control strain.

CONCLUSIONS

We identified six compounds that significantly reduced expression of S. Typhimurium virulence genes resulting in decreased in vitro virulence.

SIGNIFICANCE AND IMPACT OF THE STUDY

The emergence of multidrug-resistant strains of Salmonella poses a considerable and growing worldwide threat to human and animal health. The screening of off-patent chemical libraries represents a potential discovery route for novel antimicrobials.

NEURAPRO: a multi-centre RCT of omega-3 polyunsaturated fatty acids versus placebo in young people at ultra-high risk of psychotic disorders-medium-term follow-up and clinical course

This study reports a medium-term follow-up of a randomised, double-blind, placebo-controlled trial of omega-3 polyunsaturated fatty acids (PUFA) in ultra-high risk for psychosis (UHR) patients. Primary outcomes of interest were transition to psychosis and symptomatic and functional outcome. A secondary aim was to investigate clinical predictors of medium-term outcome. Three hundred four UHR participants were recruited across 10 specialised early psychosis services in Australia, Asia, and Europe. The intervention consisted of 1.4 g/daily of omega-3 PUFA or placebo, plus up to 20 sessions of cognitive-behavioural case management (CBCM), over the 6-month study period, with participants receiving further CBCM sessions on basis of need between months 6-12. Mean time to follow-up was 3.4 (median = 3.3; SD = 0.9) years. There was a modest increase in transitions between 12-month and medium-term follow-up (11-13%) and substantial improvement in symptoms and functioning between baseline and follow-up, with no differences between the treatment groups. Most improvement had been achieved by end of the intervention. 55% of the sample received mental health treatment between end of intervention and follow-up. Omega-3 PUFA did not provide additional benefits to good quality psychosocial intervention over the medium term. Although most improvement had been achieved by end of intervention the substantial rates of post-intervention mental health service use indicate longer-term clinical need in UHR patients. The post-intervention phase treatment or the longer-term effect of CBCM, or a combination of the two, may have contributed to maintaining the gains achieved during the intervention phase and prevented significant deterioration after this time.

Isolation of [Actinobacillus] rossii from an aborted piglet

CASE REPORT

This report describes an investigation into the cause of abortions on a commercial pig farm in Victoria in October 2015 in which six sows aborted over a 2-month period. Four of the abortions occurred in the 3 weeks prior to the sows' anticipated farrowing dates and the other two occurred in the second trimester of pregnancy. An analysis of farm data showed that the abortion rate in the previous 12 months (2014-15) was more than twice that of the previous 2 years (1.2% vs 0.5%). Parity appeared not to be a risk factor for abortions. There were no other indicators of reproductive failure on the farm and there were no obvious clinical signs of disease in affected sows. Placenta and aborted fetuses for postmortem analysis were collected while one of the sows was aborting. The only gross abnormality detected in piglets was reddening over the skin. On gross examination the surfaces of the placentas appeared diffusely thickened and 'furry'. Histological examination of fixed placenta from one of two piglets showed a severe, acute, multifocal, necrosuppurative placentitis. Gram staining of a histological section of the placenta revealed abundant Gram-negative short bacilli, consistent with Pasteurella-Actinobacillus spp. A sample of stomach contents from one piglet yielded a profuse predominant growth of bacteria described as Pseudomonas-like. This organism was subsequently identified using 16sRNA sequencing to have 98% homology with [Actinobacillus] rossii.

CONCLUSION

This is the first reported case of [A.] rossii isolated from an aborted pig's stomach in Australia.

The Ultra-High-Risk for psychosis groups: Evidence to maintain the status quo

Individuals are considered Ultra-High-Risk (UHR) for psychosis if they meet a set of standardised criteria including presumed genetic vulnerability (Trait), or a recent history of Attenuated Psychotic Symptoms (APS) or Brief Limited Intermittent Psychotic Symptoms (BLIPS). Recent calls to revise these criteria have arisen from evidence that Trait, APS and BLIPS groups may transition to psychosis at different rates. Concurrently, it has become clear that the UHR status confers clinical risk beyond transition to psychosis. Specifically, most UHR individuals will not develop psychosis, but will experience high rates of non-psychotic disorders, persistent APS and poor long-term functional outcomes. Rather than focus on transition, the present study investigated whether UHR groups differ in their broader clinical risk profile by examining baseline clinical characteristics and long-term outcomes other than transition to psychosis. Four UHR groups were defined: Trait-only, APS-only, Trait+APS, and any BLIPS. Participants (N=702) were recruited upon entry to early intervention services and followed-up over a period of up to 13years (mean=4.53, SD=3.84). The groups evidenced similar symptom severity (SANS for negative symptoms, BPRS for positive and depression/anxiety symptoms) and psychosocial functioning (SOFAS, GAF, QLS) at baseline and follow-up as well as similar prevalence of non-psychotic disorders at follow-up. Our findings demonstrate that UHR groups evidence a similar clinical risk profile when we expand this beyond transition to psychosis, and consequently support maintaining the existing UHR criteria.

Neuraxial analgesia is not associated with an increased risk of post-partum relapses in MS

Background:

Obstetrical analgesia remains a matter of controversy because of the fear of neurotoxicity of local anesthetics on demyelinated fibers or their potential relationship with subsequent relapses.

Objective:

To assess the impact of neuraxial analgesia on the risk of relapse during the first 3 months post-partum, with a focus on women who experienced relapses during pregnancy.

Methods:

We analyzed data of women followed-up prospectively during their pregnancies and at least 3 months post-partum, collected in the Pregnancy in Multiple Sclerosis (PRIMS) and Prevention of Post-Partum Relapses with Progestin and Estradiol in Multiple Sclerosis (POPARTMUS) studies between 1992–1995 and 2005–2012, respectively. The association of neuraxial analgesia with the occurrence of a post-partum relapse was estimated by logistic regression analysis.

Results:

A total of 389 women were included, 215 from PRIMS and 174 from POPARTMUS. In total, 156 women (40%) had neuraxial analgesia. Overall, 24% experienced a relapse during pregnancy and 25% in the 3 months post-partum. Women with a pregnancy relapse were more likely to have a post-partum relapse (odds ratio (OR) = 1.83, p = 0.02), independently of the use of neuraxial analgesia. There was no association between neuraxial analgesia and post-partum relapse (OR = 1.08, p = 0.78).

Conclusion:

Neuraxial analgesia was not associated with an increased risk of post-partum relapses, whatever multiple sclerosis (MS) activity during pregnancy.

Abstract P4-02-04: Quantitative MRI features analysis for differentiation of triple negative and HER2 positive subtypes of breast cancer

Objective: The aim of this study was to evaluate ability of quantitative analysis of MRI features to distinguish triple negative (TN) and HER2 positive (HER2+) subtypes of breast cancer, which have different biological characteristics, exhibiting different growth patterns and response to treatment.

Materials and Method: Breast cancer patients, who had MRI exam of the breast in our institution at the time of staging for breast carcinoma and who subsequently had surgery (segmentectomy or mastectomy) from January 1, 2008 through December 31, 2015 were identified. All lesions were evaluated by radiologists in accordance with the BI-RADS lexicon. The patient's age, breast cancer histology, multifocality/multicentricity (MF/MC), lesion size, axillary lymphadenopathy (LAN), MRI morphologic and enhancement characteristics were documented. Quantitative MRI feature analysis was performed using shape, texture, and histogram based features. Machine-learning-based (Xgboost) models were used to predict subtypes, and Leave-one-out cross-validation (LOOCV) was used to avoid model overfitting. Statistical significance was determined using the Student's t-test.

Results: Total of 105 patients, 51 patients with TN and 54 patients with HER2+ breast cancer were included in analysis. Mean age for TN was 50 (range 29-79)) years old and for HER2+ was 49 (range 25-70) years old. Axillary LAN and MF/MC disease was seen more commonly in HER2+ patients when compared to TN patients, but didn't reach statistical significance (13 vs 7, p=0.9; and 31 vs 20, p=0.06, respectively). Mass rim enhancement was associated with TN subtype and irregular mass enhancement was associated with HER2+ subtype of breast cancer (p&lt;0.05). Quantitative analysis showed that six out of the top 10 ranked MRI features: surface to volume ratio, difference variance, difference entropy, inverse difference moment, 75 percentile in histogram and sum average, were significantly different between these 2 subtypes with p&lt;0.05. When the significant features were incorporated to distinguish TN and HER+ subtypes, use of the top 2 features achieved the best accuracy on LOOCV of 0.69.

Conclusion: The quantitative MRI features show promise in distinguishing TN and HER2+ breast cancer subtypes reflecting their underlying biological characteristics and may be used as predictive quantitative biological markers. Further studies in a larger cohort evaluating associations with treatment response are underway.

FeatureIndexP-valueSurface to volume ratioShape30.005Difference VarianceGLCM110.005Difference EntropyGLCM100.009Inverse Difference MomentGLCM50.01875 percentile in histogramHistogram50.043Sum AverageGLCM60.044Median in histogramHistogram 30.08025 percentile in histogramHistogram 40.095VolumeShape10.104Max in histogramHistogram 10.105

Citation Format: Rauch GM, Li H, Zhu H, Adrada BE, Santiago L, Candelaria RP, Wang H, Leung J, Thompson A, Litton J, Wu Y, Lim B, Moulder S, Mittendorf EA, Yang W. Quantitative MRI features analysis for differentiation of triple negative and HER2 positive subtypes of breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-02-04.

Abstract P5-05-01: A molecularly annotated collection of breast cancer patient-derived xenograft models aligned with ongoing clinical trials built from fine needle aspiration samples throughout neoadjuvant treatment

BACKGROUND: Patient-derived xenograft (PDX) models of breast cancer replicate the diverse histologic and molecular features of patient tumors and provide a renewable source of human tumor tissue. However, collection of tissue by core needle biopsy is problematic due to patient discomfort, bleeding risk and the limited number of passes a patient can tolerate. Several studies have catalogued the maintenance of molecular features of patient tumors in PDX models of breast cancer.

METHODS: To support the neoadjuvant molecular diagnostic and drug development program in triple negative breast cancer (TNBC), a pilot study was conducted to determine if fine needle aspiration (FNA) could be used for building PDX models. Subsequently, PDX models are being established in alignment with ongoing clinical trials at MDACC. The molecular evolution of patient's tumors, matched with PDXs engrafted from their tumors, is under study throughout the neoadjuvant treatment of TNBC using RNA sequencing, whole-exome sequencing, deep sequencing of cancer genes, and histologic analyses.

RESULTS: To date, 20 established PDX models have been developed and stable PDX models continue to be generated at a rate of 2-3 per month. Several of these models are derived from serial FNAs derived from patients throughout neoadjuvant treatment. These models retain histologic and molecular features of the original patient tumors. Serial patient biopsies, matched with PDX models, have enabled measurement of the mutational and transcriptomic evolution in vivo of TNBC undergoing neoadjuvant treatment.

We have standardized the use of FNAs to generate PDX models both pre- and post-neoadjuvant therapy in the following ongoing neoadjuvant clinical trials:

1. MDACC 2014-0185 (PI Stacy Moulder, 360 patients), 'ARTEMIS: A Randomized TNBC-Enrolling trial to confirm Molecular profiling Improves Survival'

2. MDACC 2014-0045 (PI Jennifer Litton, 20+ patients), 'A pilot study of BMN673 as a neoadjuvant study in patients with a diagnosis of invasive breast cancer and a deleterious BRCA mutation'

CONCLUSION: We demonstrated that PDX models from tissue collected by FNA recapitulate the biology and clinical course of the patient's tumor. Sequencing analyses revealed that neoadjuvant chemotherapy and PDX engraftment enrich for cancer gene mutations. We observe association of the rate of successful PDX engraftment with clinical parameters such as the patient's residual cancer burden (RCB) status at the time of surgery (upon completion of neoadjuvant treatment). In addition, we observe that PDX models derived from serial patient biopsies throughout treatment are more resistant to chemotherapy treatment. These models recapitulate the variety of chemotherapy responses observed in patients with TNBC and serve as powerful tools for preclinical biomarker and discovery studies.

Citation Format: Echeverria GV, Cai S, Tu Y, McCoy A, Lau R, Redwood A, Rauch G, Adrada B, Candelaria R, Santiago L, Thompson A, Litton J, Moulder S, Symmans F, Chang JT, Piwnica-Worms H. A molecularly annotated collection of breast cancer patient-derived xenograft models aligned with ongoing clinical trials built from fine needle aspiration samples throughout neoadjuvant treatment [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-05-01.

Abstract P1-07-02: Withdrawn

This abstract was withdrawn by the authors.

Abstract P3-04-01: Molecular determinants of post-mastectomy breast cancer recurrence

Introduction

The management of breast cancer (BC) patients who undergo mastectomy in the setting of 1-3 positive lymph nodes has been controversial. This retrospective Translational Breast Cancer Research Consortium study evaluated the molecular aberrations associated with locoregional recurrence (LRR) or distant metastasis (DM) compared to controls in an effort to identify molecular predictors associated with recurrence.

Methods/Materials

We identified 115 HER2 negative, therapy naïve, T 1-3 and N 0-1 BC patients treated with mastectomy and no post mastectomy radiation therapy from 1997 to present with available FFPE tissue blocks. The cohort included 32 patients with LRR, 34 with DM, and 49 controls (without recurrence) who were matched for stage, grade, hormone receptor status, age ≤ or &gt; 50, chemotherapy receipt, and margin status. Matched primary and recurrent LRR samples were available for 3 patients. Hybrid capture next generation sequencing (NGS) of 142 cancer related genes and RNAseq were performed to identify DNA/RNA alterations associated with LRR or DM. The frequency of common alterations on NGS was compared with Fisher's exact test. Expression of each gene from mRNA-Seq was treated as an explanatory variable. Immunohistochemistry (IHC) was performed for PTEN, Ki-67 and cleaved caspase 3 (CC3). PTEN loss and percentage of Ki-67 and CC3 positive cells were compared between groups with Fisher's exact test and nonparametric methods, respectively.

Results

RNAseq was performed on 115 patients; there was no difference in RNA expression levels between the groups. DNA analysis was performed on 57 patients (17 LRR, 15 DM and 25 controls), NF1 mutation rate was significantly elevated in both the LRR (24%) and DM (27%) samples compared to controls 0%; (p=0.0070). The mitogen activated protein kinase (MAPK) pathway was significantly mutated in both LRR (47%) and DM (40%) samples compared to the controls 0%; (p&lt;0.0001). There was no significant difference in the rate of alterations of the PI3K/Akt/mTOR pathway among the three groups. Of three patients with matched primary vs LRR samples, one had concordant mutations. The second patient had additional mutations in the LRR, including gain of a NF1 mutation. The third patient had complete discordance of mutations identified in primary and LRR and had gain of HER2 amplification, suggestive of a new primary. There was no significant association between the groups and the loss of PTEN expression or CC3 expression. There was a significant difference between Ki 67 positive cells in patients with LRR (mean 29%), DM (mean 26%) versus controls (mean 14%, p= 0.0011). HR+ patients were significantly more likely to have a positive PTEN, lower Ki-67 and lower CC3 expression, p=0.0004, p&lt;0.0001, and p&lt;0.0001 respectively.

Conclusions

In this matched cohort analysis, mutations in the MAPK pathway, specifically NF1, were associated with both LRR and DM, suggesting that alterations in this pathway are associated with a more aggressive tumor phenotype. However, there were no molecular features that discriminated between those likely to recur locally alone versus distantly. Further study is needed to validate these findings, and to determine whether targeting alterations in this pathway could decrease the risk of recurrence.

Citation Format: Keene KS, King T, Hwang ES, Peng B, McGuire K, Tapia C, Zhang H, Bae S, Nakhlis F, Klauber-Demore N, Meszoely I, Sabel MS, Willey SC, Eterovic KA, Hudis C, Wolff A, De Los Santos J, Thompson A, Mills GB, Meric-Bernstam F. Molecular determinants of post-mastectomy breast cancer recurrence [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-04-01.

Abstract P4-15-13: When is cancer not really cancer? The PREvent ductal carcinoma in situ invasive overtreatment now (PRECISION)* initiative

Background

Ductal carcinoma in situ (DCIS) now represents 20-25% of all breast neoplasia due to large-scale detection by widely adopted population-based breast cancer screening programs. As a result, thousands of women are confronted with DCIS each year: more than 8,000 in the UK, 2,500 in the Netherlands, and some 50,000 in the US. Conventional management includes surgery, supplemented by radiotherapy and/or endocrine therapy, but overtreats the majority of DCIS as ˜1% recur annually and breast cancer mortality is ˜3% at 20 years. Uncertainty as to which DCIS lesions will progress to invasive cancer or, after excision, which will return with recurrent DCIS or invasive breast cancer drives this overtreatment. This urges us to learn how to distinguish DCIS that may progress to invasive breast cancer from the majority of indolent DCIS. Such distinction may be best achieved by synergistic international collaboration between leading global experts from various disciplines, driven by the essential input from patient voices as full members of the research team.

Aim

PRECISION (PREvent ductal Carcinoma In Situ Invasive Overtreatment Now) aims to save thousands of women with low risk DCIS the burden of intensive inappropriate treatment of DCIS (surgery, radiation therapy, hormonal therapies) through the discovery of new data and development of novel tests that promote informed and shared decision-making between patients and clinicians, without compromising the excellent outcomes for DCIS management presently achieved.

Methods

First, three large DCIS cohorts and supplementary resources will be collected enabling in depth molecular studies. Second, extensive genomic characterization, immune profiling and imaging analysis will be performed. In vivo and in vitro modeling will be performed to study the biology of DCIS in detail. Finally, all clinical, immune, and molecular data will be incorporated into a clinical risk prediction model. This risk prediction model will be validated in three prospective randomized DCIS trials in the US (COMET trial), UK (LORIS trial), and mainland Europe (LORD trial).

How the results of this research will be used

The discoveries from our laboratory studies, including a risk stratification model, will be cross-validated in three prospective trials of DCIS active surveillance versus conventional treatment (the COMET, LORIS and LORD trials). As such, the main result of this study will be that we can identify a group of women for which active surveillance for DCIS could be a safer alternative to intensive treatment. Ultimately, this may also contribute to a more reassuring perception of risk regarding non-life threatening precancerous lesions in general, reducing anxiety and preserving quality of life.

* The PRECISION Team is a Cancer Research UK Grand Challenge Award 2017 winning team and will be jointly funded by Cancer Research UK and the Dutch Cancer Society.

Citation Format: Wesseling J, Thompson A, Nik-Zainal S, Futreal A, Hwang S, Jonkers J, Lips E, Rea D, On Behalf of the PRECISION Team. When is cancer not really cancer? The PREvent ductal carcinoma in situ invasive overtreatment now (PRECISION)* initiative [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-15-13.

Abstract P4-14-02: CSF1/CSF1R axis reprograms epithelial-to-mesenchymal phenotypes in inflammatory breast cancer

Inflammatory breast cancer (IBC) accounts for 2% of breast cancers but 10% of breast cancer-related deaths in the US. Clinical hallmarks of IBC are tumor cell emboli in lymphatic vessels and overexpression of E-cadherin, which promotes cell clustering. Given these hallmarks, IBC is thought to spread via collective invasion and cell clusters. However, we showed that IBC cells underwent epithelial-to-mesenchymal transition (EMT) and metastasized through EMT. Thus, there are two contradictory theories of IBC metastasis. The objectives of this study were 1) to propose a model that reconciles these two models, and 2) to identify target molecules for inhibition of IBC metastasis. Methods: We previously showed that Matrigel culture induced EMT-like changes in SUM149 IBC cells. To test if this transformation from epithelial (E) to mesenchymal (M) in Matrigel culture is unique to IBC cells, a panel of breast cancer cells was cultured in both monolayer and Matrigel-coated plates. The cells were IBC (SUM149, SUM190, KPL4, IBC3), triple-negative breast cancer (TNBC) (MDA-MB-231, MDA-MB-468), and ER+ (MCF7) cells. Phenotypic changes in morphology and expression of EMT markers (E-cadherin, vimentin) were captured with bright field and immunofluorescent (IF) images, respectively. For genome-wide and targeted transcriptional analysis, SUM149 cells cultured in monolayer and Matrigel were processed using DNA microarrays and Taqman qRT-PCR. To correlate the Matrigel gene signature with M features in human breast cancer, a human breast cancer data set was hierarchically clustered with the Matrigel gene signature. Results: SUM149 cells showed a remarkable phenotypic change from E in monolayer culture to M in Matrigel. IF analysis confirmed induction of vimentin expression in Matrigel but stable expression of E-cadherin (thus, we refer to this state as E/M hybrid). This trend was also observed with SUM190 cells. Using qRT-PCR, we confirmed downregulation of E-cadherin and upregulation of M markers (vimentin, Twist1, Snail1, ZEB2) in Matrigel-cultured SUM149 and SUM190 cells compared to monolayer-cultured cells. DNA microarray transcriptional analysis confirmed this trend in SUM149 cells. TNBC has more M-like features than other breast cancer subtypes. Given this evidence, we clustered human breast cancer data using overexpressed genes in Matrigel-cultured SUM149 cells. We identified a cluster of 20 genes in TNBC samples and, assuming that these genes are drivers of E to E/M transition, chose the inflammation-related gene CSF1 as a candidate. The CSF1/CSF1R axis was inhibited by a CSF1R inhibitor, BLZ945; moreover, treatment with BLZ945 reversed the EMT changes in cells in Matrigel culture. Treatment with 5 μM BLZ945 re-induced E-cadherin expression and suppressed Snail1 and Twist1 expression in Matrigel-cultured SUM149 cells. Conclusion: IBC cells are more prone to undergo transition from E to E/M phenotype in Matrigel culture than are cells of other breast cancer subtypes. The CSF1/CSF1R axis plays a role in this E to E/M transition, thus warranting testing its significance using an in vivo IBC model. Phenotypic transition and reversion between E and E/M phenotypes could be a new paradigm that reconciles two contradictory models of IBC metastasis.

Citation Format: Kai K, Iwamoto T, Zhang D, Rao AUK, Thompson A, Sen S, Ueno NT. CSF1/CSF1R axis reprograms epithelial-to-mesenchymal phenotypes in inflammatory breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-14-02.

Abstract PD8-03: ESR1 gene fusions drive endocrine therapy resistance and metastasis in breast cancer

Background. Dysregulation of the estrogen receptor gene (ESR1) is an established mechanism of inducing endocrine therapy resistance. We previously discovered a chromosomal translocation event generating an estrogen receptor gene fused in-frame to C-terminal sequences of YAP1 (ESR1-YAP1) that contributed to endocrine therapy resistance in estrogen receptor positive (ER+) breast cancer models. This study compares functional, transcriptional, and pharmacological properties of additional ESR1 gene fusion events of both early stage (ESR1-NOP2) late stage (ESR1-YAP1 and ESR1-PCDH11x) breast cancers to gain a better understanding of therapeutic resistance and metastasis. Understanding the role of ESR1 fusions in inducing metastasis is critical, since the primary cause of death in breast cancer patients is through metastasis to distant sites.

Methods. RNA-seq screens identified ESR1 fusions from early and late stage, endocrine therapy resistant breast tumor samples. Functional experiments were conducted using ER+ breast cancer cell lines, xenograft, and PDX models to test the ability of ESR1 fusions to induce therapeutic resistance and metastasis. ChIP-seq and RNA-seq were performed to examine transcriptional properties and differential gene expression induced by the fusions which directed subsequent pharmacological experiments with a CDK4/6 inhibitor.

Results. ESR1-YAP1 and ESR1-PCDH11x promoted estrogen-independent and fulvestrant-resistant growth in vitro and induced greater tumor growth and increased metastatic capacity to the lungs of xenografted mice. In contrast, the ESR1-NOP2 fusion was sensitive to low estrogen conditions in vitro, and did not promote tumor growth. RNA-seq profiling revealed E2F targets pathway as the most highly enriched pathway induced by the ESR1 fusions. IHC revealed higher levels of pRb in ESR1-YAP1 and ESR1-PCDH11x xenograft tumors and subsequent CDK4/6 inhibition completely blocked tumor growth in an ESR1-YAP1 PDX model. Integrating RNA-seq with ChIP-seq data, we discovered a set of EMT and metastasis genes bound by all ESR1 fusions and WT-ER, but whose expression was strongly and uniquely up-regulated only by the ESR1-YAP1 and ESR1-PCDH11x fusions. These studies also revealed gained sites bound only by the ESR1-YAP1 and ESR1-PCDH11x fusions, not bound by WT-ER nor ESR1-NOP2. Genes mapping to these sites have a role in metastatic biology and were highly up-regulated by the YAP1 and PCDH11x fusions, potentially mediated by long range transcriptional activation.

Conclusion. ESR1-YAP1 and ESR1-PCDH11x are driver fusions that occur in drug-resistant, advanced stage breast cancer and are a new class of recurrent somatic mutation that can cause acquired endocrine therapy resistance, yet can be treated with CDK4/6 inhibition. These driver fusions also confer increased metastatic ability through their ability to drive expression of genes that contribute to EMT and metastasis. In contrast, ESR1-NOP2 did not produce functional protein and appears to be a passenger event. These studies may provide pre-clinical rationale for targeting ESR1 translocated breast tumors, since the presence of an ESR1 driver fusion places a patient in a therapeutic category where none of the currently available endocrine therapies are likely to be effective.

Citation Format: Lei JT, Shao J, Zhang J, Iglesia M, Chan DW, Cao J, Anurag M, Singh P, Haricharan S, Kavuri SM, Matsunuma R, Schmidt C, Kosaka Y, Crowder R, Hoog J, Phommaly C, Goncalves R, Ramalho S, Rodrigues-Peres RM, Lai W-C, Hampton O, Rogers A, Tobias E, Parikh P, Davies S, Ma C, Suman V, Hunt K, Watson M, Hoadley KA, Thompson A, Perou CM, Creighton CJ, Maher C, Ellis MJ. ESR1 gene fusions drive endocrine therapy resistance and metastasis in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD8-03.

HBeAg levels at week 24 predict response to 8 years of tenofovir in HBeAg-positive chronic hepatitis B patients

BACKGROUND

Hepatitis B e antigen (HBeAg) seroconversion is a treatment endpoint for HBeAg-positive CHB, and a necessary precursor to HBsAg loss. Biomarkers that predict serological outcomes would be useful.

AIM

To evaluate the utility of measuring HBeAg levels for predicting HBeAg seroconversion and HBsAg loss under long-term tenofovir (TDF) therapy.

METHODS

A total of 266 patients were enrolled into a phase III study of TDF vs adefovir (ADV) for 48 weeks in HBeAg-positive patients, followed by open-label TDF up to 384 weeks. Serum HBeAg levels were measured for subjects with samples available at both baseline and week 24 of treatment (n = 200). Analysis compared subjects who achieved HBeAg seroconversion by week 384 vs no HBeAg seroconversion.

RESULTS

HBeAg seroconversion rate was 52% by week 384. Time to HBeAg seroconversion was 80 weeks (IQR: 36-162). HBeAg decline at week 24 was associated with HBeAg seroconversion (1.63 vs 0.90 log₁₀ PEIU/mL, P = .002). The optimal threshold for identifying HBeAg seroconversion was HBeAg decline ≥2.2 log₁₀ PEIU/mL at week 24, with HBeAg seroconversion achieved by 76% of patients, compared to 44% if HBeAg decline <2.2 log₁₀ (P < .0001). HBeAg decline ≥2.2 log₁₀ PEIU/mL at week 24 was associated with HBsAg loss in genotype A or D patients (38% vs 15%, P = .03). Precore/basal core promotor variants were associated with lower baseline HBeAg levels, but not HBeAg seroconversion.

CONCLUSION

Decline in HBeAg levels by week 24 was associated with HBeAg seroconversion and HBsAg loss in HBeAg-positive chronic hepatitis B patients treated with long-term TDF.

A feasibility study of neoadjuvant talazoparib for operable breast cancer patients with a germline BRCA mutation demonstrates marked activity

This study was undertaken to determine the feasibility of enrolling breast cancer patients on a single-agent-targeted therapy trial before neoadjuvant chemotherapy. Specifically, we evaluated talazoparib in patients harboring a deleterious BRCA mutation (BRCA+). Patients with a germline BRCA mutation and ≥1 cm, HER2-negative primary tumors were eligible. Study participants underwent a pretreatment biopsy, 2 months of talazoparib, off-study core biopsy, anthracycline, and taxane-based chemotherapy ± carboplatin, followed by surgery. Volumetric changes in tumor size were determined by ultrasound at 1 and 2 months of therapy. Success was defined as 20 patients accrued within 2 years and <33% experienced a grade 4 toxicity. The study was stopped early after 13 patients (BRCA1 + n = 10; BRCA2 + n = 3) were accrued within 8 months with no grade 4 toxicities and only one patient requiring dose reduction due to grade 3 neutropenia. The median age was 40 years (range 25–55) and clinical stage included I (n = 2), II (n = 9), and III (n = 2). Most tumors (n = 9) were hormone receptor-negative, and one of these was metaplastic. Decreases in tumor volume occurred in all patients following 2 months of talazoparib; the median was 88% (range 30–98%). Common toxicities were neutropenia, anemia, thrombocytopenia, nausea, dizziness, and fatigue. Single-agent-targeted therapy trials are feasible in BRCA+ patients. Given the rapid rate of accrual, profound response and favorable toxicity profile, the feasibility study was modified into a phase II study to determine pathologic complete response rates after 4–6 months of single-agent talazoparib.

An investigational PARP inhibitor seems safe and possibly effective when given ahead of surgery to women with BRCA-mutated breast cancer. Jennifer Litton and colleagues from the University of Texas MD Anderson Cancer Center in Houston, USA, conducted a small feasibility study to see if patients with stage I-III breast cancer and inherited mutations in BRCA1 or BRCA2 would put off their standard course of chemotherapy ahead of surgery to first receive two months of talazoparib, an experimental inhibitor of poly ADP ribose polymerase (PARP), an enzyme involved in DNA damage repair. The trial was a resounding success. In fact, owing to rapid patient enrollment, decreases in tumor volume among all 13 participants and few signs of serious side effects, the researchers amended the study protocol to give talazoparib for longer and test for therapeutic efficacy.