Effectiveness and toxicity of five-fraction prone accelerated partial breast irradiation

PURPOSE

Our institution was an early adopter of 5-fraction accelerated partial breast irradiation (ABPI) to treat women with early-stage breast cancer. This study reports long-term oncologic and cosmetic outcomes.

METHODS

We included patients receiving APBI 600 cGy × 5 fx delivered every other day or every day between 2010 and 2022. Logistic regression models were used to identify factors associated with development of late toxicities, clinician, and patient-rated cosmesis. Kaplan-Meier methodology was used to calculate overall survival (OS), disease-free survival (DFS), and locoregional recurrence-free survival (LR-RFS).

RESULTS

442 patients received APBI either daily (56%) or every other day (44%) in the prone position (92%). At a median follow-up of 48 months (range: 5.96-155 months), 12 (2.7%) patients developed a local recurrence (LR). Out of 258 patients with > 3-month toxicity data available, the most common late grade ≥ 2 adverse event was breast fibrosis (6.2%). On multivariate analysis, daily APBI treatment (vs every other day) did not correlate with an increased risk of any late grade ≥ 2 toxicity though it did correlate with a lower risk of any late grade ≥ 2 fibrosis. Overall, at a median follow-up of 80 months, the rates of good-excellent physician and patient-rated cosmesis were 95% and 85%, respectively, with no difference between patients treated on consecutive vs. every other day. On multivariate analysis, patients who did not receive any adjuvant therapy were at increased risk of developing a LR. Five-year OS, LRFS, and DFS were 97.2%, 97.7%, and 89.5%, respectively.

CONCLUSIONS

Five-fraction APBI delivered primarily in the prone position either daily or every other day was effective with low rates of local recurrence, minimal toxicity, and excellent cosmesis at long-term follow-up.

Image-based multiplex immune profiling of cancer tissues: translational implications. A report of the International Immuno-oncology Biomarker Working Group on Breast Cancer

Recent advances in the field of immuno-oncology have brought transformative changes in the management of cancer patients. The immune profile of tumours has been found to have key value in predicting disease prognosis and treatment response in various cancers. Multiplex immunohistochemistry and immunofluorescence have emerged as potent tools for the simultaneous detection of multiple protein biomarkers in a single tissue section, thereby expanding opportunities for molecular and immune profiling while preserving tissue samples. By establishing the phenotype of individual tumour cells when distributed within a mixed cell population, the identification of clinically relevant biomarkers with high-throughput multiplex immunophenotyping of tumour samples has great potential to guide appropriate treatment choices. Moreover, the emergence of novel multi-marker imaging approaches can now provide unprecedented insights into the tumour microenvironment, including the potential interplay between various cell types. However, there are significant challenges to widespread integration of these technologies in daily research and clinical practice. This review addresses the challenges and potential solutions within a structured framework of action from a regulatory and clinical trial perspective. New developments within the field of immunophenotyping using multiplexed tissue imaging platforms and associated digital pathology are also described, with a specific focus on translational implications across different subtypes of cancer. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Single pulmonary nanopolystyrene exposure in late-stage pregnancy dysregulates maternal and fetal cardiovascular function

Largescale production and waste of plastic materials has resulted in widespread environmental contamination by the breakdown product of bulk plastic materials to micro and nanoplastics (MNPs). The small size of these particles enables their suspension in the air, making pulmonary exposure inevitable. Previous work has demonstrated that xenobiotic pulmonary exposure to nanoparticles during gestation leads to maternal vascular impairments, as well as cardiovascular dysfunction within the fetus. Few studies have assessed the toxicological consequences of maternal nanoplastic exposure; therefore, the objective of this study was to assess maternal and fetal health after a single maternal pulmonary exposure to polystyrene nanoplastic in late gestation. We hypothesized that this acute exposure would impair maternal and fetal cardiovascular function. Pregnant rats were exposed to nanopolystyrene on gestational day 19 via intratracheal instillation. 24 h later, maternal and fetal health outcomes were evaluated. Cardiovascular function was assessed in dams using vascular myography ex vivo and in fetuses in vivo function was measured via ultrasound. Both fetal and placental weight were reduced after maternal exposure to nanopolystyrene. Increased heart weight and vascular dysfunction in the aorta were evident in exposed dams. Maternal exposure led to vascular dysfunction in the radial artery of the uterus, a resistance vessel that controls blood flow to the fetoplacental compartment. Function of the fetal heart, fetal aorta, and umbilical artery after gestational exposure was dysregulated. Taken together, these data suggest that exposure to nanoplastics negatively impacts maternal and fetal health, highlighting the concern of MNPs exposure on pregnancy and fetal development.

Long-term Survival From Breast Cancer Brain Metastases in the Era of Modern Systemic Therapies

BACKGROUND AND OBJECTIVES

Median survival for all patients with breast cancer with brain metastases (BCBMs) has increased in the era of targeted therapy (TT) and with improved local control of intracranial tumors using stereotactic radiosurgery (SRS) and surgical resection. However, detailed characterization of the patients with long-term survival in the past 5 years remains sparse. The aim of this article is to characterize patients with BCBM who achieved long-term survival and identify factors associated with the uniquely better outcomes and to find predictors of mortality for patients with BCBM.

METHODS

We reviewed 190 patients with breast cancer with 931 brain tumors receiving SRS who were followed at our institution with prospective data collection between 2012 and 2022. We analyzed clinical, molecular, and imaging data to assess relationship to outcomes and tumor control.

RESULTS

The median overall survival from initial SRS and from breast cancer diagnosis was 25 months (95% CI 19-31 months) and 130 months (95% CI 100-160 months), respectively. Sixteen patients (17%) achieved long-term survival (survival ≥5 years from SRS), 9 of whom are still alive. Predictors of long-term survival included HER2+ status ( P = .041) and treatment with TT ( P = .046). A limited number of patients (11%) died of central nervous system (CNS) causes. A predictor of CNS-related death was the development of leptomeningeal disease after SRS ( P = .025), whereas predictors of non-CNS death included extracranial metastases at first SRS ( P = .017), triple-negative breast cancer ( P = .002), a Karnofsky Performance Status of <80 at first SRS ( P = .002), and active systemic disease at last follow-up ( P = .001). Only 13% of patients eventually needed whole brain radiotherapy. Among the long-term survivors, none died of CNS progression.

CONCLUSION

Patients with BCBM can achieve long-term survival. The use of TT and HER2+ disease are associated with long-term survival. The primary cause of death was extracranial disease progression, and none of the patients living ≥5 years died of CNS-related disease.

Comparison of imputation methods for missing production data of dairy cattle

Nowadays, vast amounts of data representing feed intake, growth, and environmental impact of individual animals are being recorded in on-farm settings. Despite their apparent use, data collected in real-world applications often have missing values in one or several variables, due to reasons including human error, machine error, or sampling frequency misalignment across multiple variables. Since incomplete datasets are less valuable for downstream data analysis, it is important to address the missing value problem properly. One option may be to reduce the dataset to a subset that contains only complete data, but considerable data may be lost via this process. The current study aimed to compare imputation methods for the estimation of missing values in a raw dataset of dairy cattle including 454 553 records collected from 629 cows between 2009 and 2020. The dataset was subjected to a cleaning process that reduced its size to 437 075 observations corresponding to 512 cows. Missing values were present in four variables: concentrate DM intake (CDMI, missing percentage = 2.30%), forage DM intake (FDMI, 8.05%), milk yield (MY, 15.12%), and BW (64.33%). After removing all missing values, the resulting dataset (n = 129 353) was randomly sampled five times to create five independent subsets that exhibit the same missing data percentages as the cleaned dataset. Four univariate and nine multivariate imputation methods (eight machine learning methods and the MissForest method) were applied and evaluated on the five repeats, and average imputation performance was reported for each repeat. The results showed that Random Forest was overall the best imputation method for this type of data and had a lower mean squared prediction error and higher concordance correlation coefficient than the other imputation methods for all imputed variables. Random Forest performed particularly well for imputing CDMI, MY, and BW, compared to imputing FDMI.

Nanoparticles at the maternal-fetal interface

The increasing production of intentional and unintentional nanoparticles (NPs) has led to their accumulation in the environment as air and ground pollution. The heterogeneity of these particles primarily relies on the NP physicochemical properties (i.e., chemical composition, size, shape, surface chemistry, etc.). Pregnancy represents a vulnerable life stage for both the woman and the developing fetus. The ubiquitous nature of these NPs creates a concern for developmental fetal exposures. At the maternal-fetal interface lies the placenta, a temporary endocrine organ that facilitates nutrient and waste exchange as well as communication between maternal and fetal tissues. Recent evidence in human and animal models identifies that gestational exposure to NPs results in placental translocation leading to local effects and endocrine disruption. Currently, the mechanisms underlying placental translocation and cellular uptake of NPs in the placenta are poorly understood. The purpose of this review is to assess the current understanding of the physiochemical factors influencing NP translocation, cellular uptake, and endocrine disruption at the maternal-fetal interface within the available literature.

Effectiveness and Toxicity of Five Fraction Prone Accelerated Partial Breast Irradiation

PURPOSE/OBJECTIVE(S)

Accelerated partial breast irradiation (APBI) after breast conserving therapy (BCT) is increasingly used to treat women with early stage breast cancer. Our institution was an early adopter of 5-fraction ABPI and delivers APBI primarily to patients in the prone position. This study reports long term oncologic and cosmetic outcome in a large cohort of women treated with 5-fraction external beam APBI.

MATERIALS/METHODS

We included patients receiving APBI 600 cGy × 5 fx delivered every other day or every day between 2010 and 2022. Late toxicities and clinician and patient rated cosmesis were evaluated for patients with > 6 month follow up. Univariate and multivariate logistic regression models were used to identify clinical and dosimetric factors associated with development of acute and late toxicities, clinician and patient rated cosmesis. All statistical tests were two-sided, and the null hypothesis was rejected for p<0.05. Kaplan Meier methodology was used to calculate overall survival (OS), disease-free survival (DFS) and locoregional recurrence-free survival (LR-RFS).

RESULTS

Four hundred and forty-two patients received APBI either daily (56%) or every other day (44%). Most of the patients (92%) were treated in the prone position. Average mean heart dose was 23 cGy for left-sided and 11 cGy for right-sided breast cancers. Ipsilateral lung V30% ≤ 30%. At a median follow up of 48 months (range: 5.96 - 155 months), 12 (2.7%) patients developed a local recurrence, 14 (3.2%) patients developed a contralateral breast primary, 10 patients (2.3%) developed a distant metastasis and one patient (0.2%) developed a local recurrence followed by a distant metastasis 1 month later. Out of 258 patients with > 6 month follow up, rates of late grade 1-2 telangiectasia, fibrosis, edema, atrophy and hyperpigmentation were 4%, 18%, 1%, 19% and 7% respectively. There was only one late grade 3 event in a patient who developed significant breast atrophy. The rate of good-excellent physician and patient rated cosmesis was 95% and 89% respectively (N = 256 at median follow up of 80 months). On multivariate logistic regression, patients who did not receive any adjuvant endocrine or chemotherapy were at increased risk of developing a local recurrence. Patients with PR negative disease were at increased risk of distant metastasis. Patient who experienced any grade of acute dermatitis during treatment were at increased risk of any high grade (grade ≥ 2) late adverse event and worse physician rated cosmesis. Daily or every other day treatment did not correlate with worse toxicity or clinical outcomes. Plastic surgery involvement, LVI, EIC, lobular histology, and ER negativity did not correlate with an increased risk of recurrence. Five-year LR-RFS, DFS and OS were 98%, 92.5% and 98.6% respectively.

CONCLUSION

Five- fraction APBI delivered primarily in the prone position either daily or every other day was effective with low rates of local recurrence, minimal toxicity and excellent cosmetic scores at long term follow up.

Pitfalls in machine learning-based assessment of tumor-infiltrating lymphocytes in breast cancer: A report of the International Immuno-Oncology Biomarker Working Group on Breast Cancer

The clinical significance of the tumor-immune interaction in breast cancer is now established, and tumor-infiltrating lymphocytes (TILs) have emerged as predictive and prognostic biomarkers for patients with triple-negative (estrogen receptor, progesterone receptor, and HER2-negative) breast cancer and HER2-positive breast cancer. How computational assessments of TILs might complement manual TIL assessment in trial and daily practices is currently debated. Recent efforts to use machine learning (ML) to automatically evaluate TILs have shown promising results. We review state-of-the-art approaches and identify pitfalls and challenges of automated TIL evaluation by studying the root cause of ML discordances in comparison to manual TIL quantification. We categorize our findings into four main topics: (1) technical slide issues, (2) ML and image analysis aspects, (3) data challenges, and (4) validation issues. The main reason for discordant assessments is the inclusion of false-positive areas or cells identified by performance on certain tissue patterns or design choices in the computational implementation. To aid the adoption of ML for TIL assessment, we provide an in-depth discussion of ML and image analysis, including validation issues that need to be considered before reliable computational reporting of TILs can be incorporated into the trial and routine clinical management of patients with triple-negative breast cancer. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Spatial analyses of immune cell infiltration in cancer: current methods and future directions: A report of the International Immuno-Oncology Biomarker Working Group on Breast Cancer

Modern histologic imaging platforms coupled with machine learning methods have provided new opportunities to map the spatial distribution of immune cells in the tumor microenvironment. However, there exists no standardized method for describing or analyzing spatial immune cell data, and most reported spatial analyses are rudimentary. In this review, we provide an overview of two approaches for reporting and analyzing spatial data (raster versus vector-based). We then provide a compendium of spatial immune cell metrics that have been reported in the literature, summarizing prognostic associations in the context of a variety of cancers. We conclude by discussing two well-described clinical biomarkers, the breast cancer stromal tumor infiltrating lymphocytes score and the colon cancer Immunoscore, and describe investigative opportunities to improve clinical utility of these spatial biomarkers. © 2023 The Pathological Society of Great Britain and Ireland.

Association Between Biomarkers and Clinical Outcomes of Pembrolizumab Monotherapy in Patients With Metastatic Triple-Negative Breast Cancer: KEYNOTE-086 Exploratory Analysis

PURPOSE

In the two-cohort phase II KEYNOTE-086 study (ClinicalTrials.gov identifier: NCT02447003), first-line and second-line or later pembrolizumab monotherapy demonstrated antitumor activity in metastatic triple-negative breast cancer (mTNBC; N = 254). This exploratory analysis evaluates the association between prespecified molecular biomarkers and clinical outcomes.

METHODS

Cohort A enrolled patients with disease progression after one or more systemic therapies for metastatic disease irrespective of PD-L1 status; Cohort B enrolled patients with previously untreated PD-L1-positive (combined positive score [CPS] ≥ 1) metastatic disease. The association between the following biomarkers as continuous variables and clinical outcomes (objective response rate [ORR], progression-free survival [PFS], and overall survival [OS]) was evaluated: PD-L1 CPS (immunohistochemistry), cluster of differentiation 8 (CD8; immunohistochemistry), stromal tumor-infiltrating lymphocyte (sTIL; hematoxylin and eosin staining), tumor mutational burden (TMB; whole-exome sequencing [WES]), homologous recombination deficiency-loss of heterozygosity, mutational signature 3 (WES), mutational signature 2 (apolipoprotein B mRNA editing catalytic polypeptide-like; WES), T-cell-inflamed gene expression profile (Tcell_infGEP; RNA sequencing), and 10 non-Tcell_infGEP signatures (RNA sequencing); Wald test P values were calculated, and significance was prespecified at α = 0.05.

RESULTS

In the combined cohorts (A and B), PD-L1 (P = .040), CD8 (P < .001), sTILs (P = .012), TMB (P = .007), and Tcell_infGEP (P = .011) were significantly associated with ORR; CD8 (P < .001), TMB (P = .034), Signature 3 (P = .009), and Tcell_infGEP (P = .002) with PFS; and CD8 (P < .001), sTILs (P = .004), TMB (P = .025), and Tcell_infGEP (P = .001) with OS. None of the non-Tcell_infGEP signatures were associated with outcomes of pembrolizumab after adjusting for the Tcell_infGEP.

CONCLUSION

In this exploratory biomarker analysis from KEYNOTE-086, baseline tumor PD-L1, CD8, sTILs, TMB, and Tcell_infGEP were associated with improved clinical outcomes of pembrolizumab and may help identify patients with mTNBC who are most likely to respond to pembrolizumab monotherapy.

Abstract OT2-10-01: A phase 2, randomized study of magrolimab combination therapy in adult patients with unresectable locally advanced or metastatic triple-negative breast cancer

Background: Improving outcomes for patients (pts) with triple-negative breast cancer (TNBC) remains a high unmet need. Immune checkpoint inhibitors (ICIs) + chemotherapy (chemo) and single-agent sacituzumab govitecan, a trophoblast cell-surface antigen 2–targeted antibody-drug conjugate coupled to SN38 via a proprietary, hydrolysable linker, are approved in newly diagnosed pts with programmed death-ligand 1 (PD-L1)–positive tumors and pts who received ≥2 prior systemic therapies (≥1 for metastatic disease), respectively. However, additional options are urgently needed, particularly for pts with tumors that do not express PD-L1 and for those with progression on chemo ± ICI. Magrolimab is an antibody blocking CD47, a “don’t eat me” signal overexpressed on cancer cells, including TNBC, inducing tumor phagocytosis by macrophages. Magrolimab has shown preclinical activity and promising clinical efficacy in hematologic and solid tumors. Chemo agents, including taxanes, can enhance prophagocytic signals on tumor cells, leading to the potential for synergistic antitumor activity with magrolimab. This study is evaluating the safety/tolerability and efficacy of magrolimab in combination with nab-paclitaxel/paclitaxel or with sacituzumab govitecan in unresectable locally advanced/metastatic TNBC. Trial Design: This open-label, 2-cohort (C) study consists of safety run-in and phase (ph)2 portions evaluating nab-paclitaxel/paclitaxel (choice) + magrolimab (safety run-in) or ± magrolimab (ph2, randomized 1:1) in pts with untreated, advanced/metastatic TNBC ineligible for ICI (C1) and magrolimab + sacituzumab govitecan (safety run-in and ph2) in pts with advanced TNBC who received 1 prior systemic treatment in the metastatic setting (C2). Stratification factors for C1 are neoadjuvant and/or adjuvant taxane therapy, liver metastases, and nab-paclitaxel vs paclitaxel. In both cohorts, magrolimab will be administered intravenously (IV) in de-escalating doses to establish the recommended ph2 dose (RP2D). Nab-paclitaxel/paclitaxel and sacituzumab govitecan will be administered IV per standard of care. Eligibility Criteria: Eligible pts are ≥18 y with PD-L1–negative, untreated, unresectable locally advanced/metastatic TNBC (C1) or unresectable locally advanced/metastatic TNBC who received 1 prior line of therapy in the advanced setting, including a taxane and an ICI if PD-L1 positive (C2), with measurable disease per RECIST v1.1. Exclusion criteria include active central nervous system disease, red blood cell transfusion dependence, or prior treatment with CD47/signal regulatory protein α–targeting agents for both cohorts. Additional exclusions are disease progression within 6 months of (neo)adjuvant therapy or rapid visceral progression and/or symptomatic disease, for which single-agent chemo would not be appropriate (C1); chronic inflammatory bowel disease and a history of bowel obstruction or gastrointestinal perforation within 6 months of enrollment, prior treatment with topoisomerase I inhibitors or antibody-drug conjugates containing a topoisomerase inhibitor, and receipt of high-dose systemic corticosteroids within 2 weeks of cycle 1 day 1 (C2). Specific Aims: The primary objectives are safety/tolerability and magrolimab RP2D (safety run-in) and efficacy (ph2: C1, progression-free survival [PFS]; C2, objective response rate [ORR]; both by investigator). Secondary objectives include ORR, PFS, and duration of response by investigator and independent central review, overall survival, and magrolimab concentration vs time and antidrug antibodies. Present and Target Accrual: The study is enrolling in the US, Australia, and Hong Kong. Target accrual is 144 pts. Contact Information: ClinicalTrials.gov: NCT04958785.

Citation Format: Natalie Rainey, Rohit Joshi, Joanne Win Yang Chiu, Ann Chen, Hao Wang, Jared Odegard, Michael Howland, Sylvia Adams. A phase 2, randomized study of magrolimab combination therapy in adult patients with unresectable locally advanced or metastatic triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT2-10-01.

Abstract OT3-14-01: A longitudinal investigation of sociocultural and behavioral influences on symptom management, biological response, and functioning among Chinese American and White female breast cancer survivors

Background: Socioeconomically disadvantaged and immigrant cancer survivors account for a significant and growing proportion of the breast cancer population in the US. Research on symptom burden and control among Chinese American (CA) breast cancer survivors (BCS) is scarce. Among all BCS, over 55% report treatment-related symptoms (e.g., fatigue and pain) and psychological stress (e.g., fear of recurrence). In our preliminary cross-sectional study, we found similar rates (~58%) but showed that CA (especially low-acculturated) BCS were particularly likely to report fatigue, pain, and poorer physical functioning relative to non-Hispanic White (NHW) BCS. We understand very little about whether CA and NHW BCS have different ways of managing symptoms, improving quality of life and decreasing risk for functional decline. We therefore propose a study to examine how CA and NHW BCS, two culturally distinct groups with divergent social resources, adapt to breast cancer. Study design: This longitudinal, prospective study will investigate sociocultural influences on individual coping behaviors and how they in turn affect racial differences in inflammation markers, symptom severity, and functional outcomes in breast cancer. This study will enroll 260 CA and 260 NHW female BCS to examine multifactorial pathways to breast cancer survivorship outcomes. The CA cases will be age- and stage-matched to the NHW cases. Utilizing a multilevel biobehavioral framework, we will investigate the dynamics of biological, sociocultural, and behavioral (diet and exercise) influences on symptom severity, physiologic status, and functional outcomes. Participants will complete telephone survey interviews and provide blood samples at baseline and 6- and 12-month follow-up. Pro-inflammatory cytokines (e.g., IL-1β, IL-1a, IL-6, IL8, IL10, TNFα, TNFꞵ, and CRP) and cortisol will be analyzed. In-depth individual interviews with a subset of participants will be conducted to investigate causal factors in order to develop individually and culturally appropriate interventions to improve future clinical care for targeted breast cancer survivor populations. This study is supported by NIH R01CA248413. Eligibility criteria: Eligible participants are CA and NWH women (age &gt;= 18) who are diagnosed with invasive breast cancer (stage I, II, or III), are 1-5 years post diagnosis, and have completed primary treatment (e.g., surgery, radiation, chemotherapy, and/or targeted therapy). Patients currently on adjuvant endocrine therapy are allowed. Specific aims: Aim 1: Examine whether CA BCS’ symptom, functional, and physiologic outcomes (e.g., cytokines and cortisol), and trajectory of these outcomes differ from NHW BCS at baseline, 6- and 12-month follow-up, controlling for covariates. Aim 2: Examine to what extent social resources mediate BCS’ individual behavior (e.g., medical communication, diet, and physical activity) and to what extent such pathways explain outcome differences (Aim1) among BCS. Aim 3: Examine whether race and acculturation moderate the mediational pathways. Statistical methods: Multiple general linear mixed models will be performed to examine racial differences in the trajectory of symptom and biobehavioral outcomes across time, controlling for covariates (Aim 1). To examine mediation and moderation effects (Aims 2 and 3), we will use a cross-lagged path analysis model to simultaneously describe reciprocal relationships, or directional influences, between variables over time. Present accrual and target accrual: A total of 520 participants (260 CA and 260 NHW) will be enrolled at NYU Perlmutter Cancer Center, Columbia University Irving Medical Center, Georgetown University Medical Center, and Texas A&M University community networks. Contact information: Judy Huei-yu Wang, PhD: jw235@gunet.georgetown.edu or 202-687-6306 Maryann Kwa, MD: maryann.kwa@nyulangone.org or 212-731-6364

Citation Format: Maryann Kwa, Marc Schwartz, Katherine D. Crew, Jeanine M. Genkinger, Roger L. Brown, Leena Hilakivi-Clarke, Joanna Kitlinska, Douglas W. Roblin, Michael Antoni, Sylvia Adams, Kathie-Ann Joseph, Lei-Shih Chen, Judy Huei-yu Wang. A longitudinal investigation of sociocultural and behavioral influences on symptom management, biological response, and functioning among Chinese American and White female breast cancer survivors [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-14-01.

Abstract OT1-03-01: XMT-1660: A Phase 1b trial of a B7-H4 targeted Antibody Drug Conjugate (ADC) in Breast, Endometrial, and Ovarian Cancers

Background: Breast cancer (BC) is the most commonly diagnosed cancer and one of the leading causes of cancer death in women. Despite significant therapeutic advances, the majority of patients with unresectable or recurrent/metastatic disease eventually develop resistance to available standard of care (SOC) therapies. B7-H4 is a poor prognostic factor and is overexpressed in several cancers including endometrial, ovarian, and breast. As a member of the CD28/B7 family of cell surface proteins, it promotes tumorigenesis by suppressing anti-tumor immunity. XMT-1660 is a B7-H4-targeted Dolasynthen antibody drug conjugate with a precise, optimized drug-to-antibody ratio and a DolaLock microtubule inhibitor payload with controlled bystander effect. In the preclinical setting, XMT-1660 has demonstrated anti-tumor activity in TNBC and ER+/HER2- patient-derived xenograft mouse models, which included tumors from heavily pre-treated patients (Collins et al, AACR 2022). Increased anti-tumor activity tended to be more frequent in models with higher B7-H4 expression, providing rationale for a Ph1 clinical trial. Methods: The Ph1 trial includes a first-in-human open-label dose escalation (DES) portion followed by dose expansion (EXP) evaluating XMT-1660 in patients with BC, EC, and OC following progression on SOC as applicable (i.e., CDK4/6i + ET; platinum-based chemotherapy). In the DES, Bayesian Optimal Interval (BOIN) design will be used to determine the MTD. Patients will receive XMT-1660 IV Q3 weeks. Primary endpoints in DES are to assess safety and determine a recommended phase 2 dose (RP2D) and assessment of preliminary efficacy as a secondary endpoint. In the EXP portion, cohorts enrolling TNBC, ER+/HER2- BC, EC/OC are planned and additional patients may be enrolled based on emerging data. The primary endpoint of EXP is to assess safety and tolerability, overall response rate, disease control rate, and duration of response. Secondary endpoints include pharmacokinetic analysis and antidrug antibodies. Patients are not selected by B7-H4 status, but baseline tumors samples are collected for retrospective tumor tissue evaluation. The trial is currently enrolling patients. NCT05377996

Citation Format: Erika Hamilton, Arvind Chaudhry, Alexander I. Spira, Sylvia Adams, Nour Abuhadra, Antonio Giordano, Ritesh Parajuli, Hyo S. Han, Amy Weise, Aubri Marchesani, Kate Josephs, Chu Ri Shin, Kevin Kalinsky. XMT-1660: A Phase 1b trial of a B7-H4 targeted Antibody Drug Conjugate (ADC) in Breast, Endometrial, and Ovarian Cancers [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-03-01.

Macrophage density is an adverse prognosticator for ipsilateral recurrence in ductal carcinoma in situ

INTRODUCTION

There is evidence that supports the association of dense tumor infiltrating lymphocyte (TILs) with an increased risk of ipsilateral recurrence in ductal carcinoma in situ (DCIS). However, the association of cellular composition of DCIS immune microenvironment with the histopathologic parameters and outcome is not well understood.

METHODS

We queried our institutional database for patients with pure DCIS diagnosed between 2010 and 2019. Immunohistochemical studies for CD8, CD4, CD68, CD163, and FOXP3 were performed and evaluated in the DCIS microenvironment using tissue microarrays. Statistical methods included Fisher's exact test for categorical variables and the two-sample t-test or the Wilcoxon Rank-Sum test for continuous variables.

RESULTS

The analytic sample included 67 patients. Median age was 62 years (range = 53 to 66) and median follow up was 6.7 years (range = 5.3 to 7.8). Thirteen patients had ipsilateral recurrence. Of all the clinicopathologic variables, only the DCIS size and TIL density were significantly associated with recurrence (p = 0.023 and 0.006, respectively). After adjusting for age and TIL density, only high CD68 (>50) and high CD68/CD163 ratio (>0.46) correlated with ipsilateral recurrence (p = 0.026 and 0.013, respectively) and shorter time to recurrence [hazard ratio 4.87 (95% CI: 1.24-19, p = 0.023) and 10.32 (95% CI: 1.34-80, p = 0.025), respectively].

CONCLUSIONS

In addition to DCIS size and TIL density, high CD68+ tumor-associated macrophages predict ipsilateral recurrence in DCIS. High CD68+ macrophage density and CD68/CD163 ratio also predict a shorter time to recurrence.

Laparoscopy uptake for paediatric appendicectomy: a comparison of general surgeons versus specialist paediatric surgeons in England from 1997 to 2015

INTRODUCTION

Laparoscopy is used in as many as 95% of adult appendicectomies. There is level I evidence showing that it reduces wound infection, postoperative ileus and length of inpatient stay in children compared with the open approach. The aim of this study was to report the uptake of laparoscopy for paediatric appendicectomy in England and to determine whether this was similar for general surgeons (GS) and specialist paediatric surgeons (SPS).

METHODS

Hospital Episode Statistics data were obtained for all children aged <16 years who had an OPCS 4.6 code for emergency appendicectomy from 1997 to 2015 (18 years). Data are analysed to compare rate of laparoscopic vs open procedures for GS and SPS over time and to investigate factors associated with the use of laparoscopy.

RESULTS

There were 196,987 appendicectomies and where specialty was available, 133,709 (79%) cases were undertaken by GS and 35,141 (21%) by SPS. The rate of cases undertaken with laparoscopy for both specialties combined increased from 0.8% in 1998 to 50% in 2014 (p<0.0001). In 2014, this rate was 41% for GS compared with 71% for SPS (p<0.0001). Female gender (odds ratio (OR)=1.84, 95% confidence interval (CI) 1.80-1.90), increasing age (OR=1.18, 95% CI 1.18-1.19 per year) and treatment by SPS (OR=3.71, 95% CI 3.60-3.82) were all factors positively associated with use of laparoscopy in multivariate analysis.

CONCLUSIONS

There has been a vast increase in the proportion of appendicectomies undertaken laparoscopically in children. Despite adjusting for patient factors, laparoscopy was used significantly less by GS when compared with SPS. This difference is most apparent in younger children.

Mechanisms of action and acquired resistance to atezolizumab plus nab-paclitaxel in metastatic triple-negative breast cancer (mTNBC)

1078

Background: In the IMpassion130 study (NCT02425891) first-line atezolizumab plus nab-paclitaxel (A+nP) provided clinical benefit compared with placebo plus nP (P+nP) in patients with mTNBC whose tumors were PD-L1+ (Schmid NEJM 2018). However, in many patients, disease that was initially controlled eventually progressed. The mechanism of action of A+nP and nP in the mTNBC tumor microenvironment (TME) and the biological changes associated with tumor progression with these therapies remain largely unknown. The goal of the current study was to evaluate biological changes in the TME induced by atezolizumab and nP early on treatment (OT) and at the time of progressive disease (PD) in IMpassion130. Methods: Paired tumor biopsies from IMpassion130 collected pre-treatment at baseline (BL), after 4 weeks OT, and at clinical PD were evaluated histologically for PD-L1 expression, CD8 content, stromal tumor infiltrating lymphocytes and immune phenotypes. RNA sequencing was also used to evaluate TNBC molecular subtypes and gene expression (hallmark gene sets, and immune cell and stromal gene signatures). Matched tumor pair samples from BL and PD were further analyzed by next-generation sequencing for genomic changes using the FoundationOne gene panel. Wilcoxon, Fisher, and McNemar’s tests were used for statistical analysis. Results: OT A+nP (n = 24 pairs), but not P+nP (n = 18 pairs) increased PD-L1 in both tumor-infiltrating immune cells and tumor cells, and increased frequency of immune-inflamed tumors. RNA-based signatures for A+nP showed an increase in lymphocytes (T-, B-, and NK cell), as well as IFN-α and IFN-γ responses, driven mainly by responders. While P+nP increased RNA-based stromal signatures (cancer-associated fibroblasts, pericytes, and angiogenesis) and epithelial mesenchymal transition, these changes were not observed with A+nP. OT A+nP and P+nP both reduced cell proliferation but only A+nP reduced metabolic pathways. At PD there was a significant reduction of RNA-based immune and stromal signatures in both A+nP (n = 59) and P+nP (n = 55) arms. Cell proliferation and DNA repair signatures were increased with A+nP but not P+nP. Evaluation of genomic changes suggested that both A+nP and P+nP increased tumor mutational burden (TMB), but only A+nP increased genomic scarring. At PD, the tumor immune phenotypes changed at PD with no directionality, while TNBC subtypes remained stable. Conclusions: A+nP boosted tumor immune inflammation and decreased tumor cell proliferation and metabolism in mTNBC patients, particularly in responders. Addition of atezolizumab prevented early stromal recruitment induced by nP. While decreased immune and stromal components and increased TMB were observed with both nP and A+nP, A+nP tumor escape was characterized by increased cell proliferation and DNA scarring. Clinical trial information: NCT02425891.

Nivolumab with chemotherapy as neoadjuvant treatment for inflammatory breast cancer

e12633

Background: Inflammatory breast cancer (IBC) is the most aggressive form of breast cancer with poor prognosis and is often resistant to neoadjuvant systemic therapy with early recurrence and metastases. PD-L1 expression in IBC is moderate to high, and blockade of the PD-1/PD-L1 axis with checkpoint inhibitors has emerged as a promising treatment to enhance clinical response. We examined the efficacy of neoadjuvant nivolumab (anti-PD-1 antibody) with chemotherapy in IBC. Methods: This is an open-label multicohort multicenter study of nivolumab with neoadjuvant chemotherapy in patients with newly diagnosed non-metastatic IBC (n=52). All breast cancer subtypes (ER/PR/HER2) were allowed. Patients received nivolumab 360 mg on day 1 (21-day cycle) x 4 cycles with standard chemotherapy. Cohort 1 (HER2-negative) received nivolumab with paclitaxel (80 mg/m2)x12 weeks followed by doxorubicin (60 mg/m2) and cyclophosphamide (600 mg/m2) (AC) x 4 cycles. Cohort 2 (HER2-positive) received nivolumab with taxane (paclitaxel 80 mg/m2, docetaxel 75 mg/m2, or nab-paclitaxel 100 mg/m2), trastuzumab (8 mg/kg then 6 mg/kg), and pertuzumab (840 mg then 420 mg) x 4 cycles followed by AC x 4 cycles. All patients underwent modified radical mastectomy (MRM) followed by radiation and adjuvant therapy per institutional standard of care. Primary objective was pathologic complete response (pCR) (ypT0/Tis ypN0). Residual Cancer Burden (RCB) was assessed. Secondary objectives were safety/tolerability and invasive recurrence-free interval at 2 years. Breast biopsies, residual tumor tissue, and peripheral blood samples were collected for correlative biomarker testing. PD-L1 expression in tumor tissue will be assessed as a predictive marker. Study was closed after 8 patients were enrolled due to slow accrual. Results: 8 patients were enrolled from June 2019-December 2020. All completed neoadjuvant systemic therapy with nivolumab and none had disease progression. They underwent MRM between January 2020-June 2021. Mean age was 57 years (range 43-74). 4 were HER2-positive, 3 were TNBC, and 1 was HR-positive/HER2-negative. 3 were Caucasian, 2 were Latino, 2 were Black, and 1 was Asian. There was no grade 4 toxicity. Most common grade 3 toxicity was neutropenia (n=3). Immune-related events were diarrhea/colitis (n=2) and elevated liver transaminases (n=1). At time of MRM, 4 patients had pCR, 1 had RCB-I, 2 had RCB-II, and 1 had RCB-III. They remain with no evidence of disease and are in follow-up. Tumor biological correlatives are being performed. Conclusions: Addition of nivolumab to neoadjuvant therapy was tolerable and safe and demonstrated anti-tumor activity in IBC with high pCR rate in this pilot study. This supports further investigation of the role of checkpoint inhibitors in treatment of IBC. Clinical trial information: NCT03742986. [Table: see text]

Impact of steroid premedication on atezolizumab (atezo)-induced immune cell activation: A comparative analysis of IMpassion130 and IMpassion131 peripheral blood mononuclear cells (PBMCs)

1083

Background: The immune checkpoint inhibitor (ICI) atezo showed disparate outcomes as first-line therapy for metastatic TNBC when combined with nab-paclitaxel (nPac) in IMpassion130 [Schmid 2018] vs solvent-based paclitaxel (Pac) in IMpassion131 [Miles 2021]. A key difference between the trials was use of steroid premedication for Pac in IMpassion131 but not for nPac in IMpassion130. In patients (pts) receiving ICIs, prior steroid exposure has been linked to worse outcome [Drakaki 2020]. Further, IMpassion130 and IMpassion131 subgroup analyses suggested reduced atezo treatment effect in taxane-pretreated pts. This post hoc biomarker study explored the impact of: 1) steroids on systemic immune cell activation with atezo+taxane; 2) prior taxane exposure on atezo-induced immune cell activation. Methods: PBMCs collected at baseline and at day 1, cycle 2 (wk 4) were selected from matched pts (RECIST responders, PD-L1+, no liver metastases) from IMpassion130 and IMpassion131. Single-cell RNAseq was performed and the transcriptomic profile of immune cells was analyzed using GSEA pathway analyses, cell proportion and TCR clonality. Results: CITEseq from 695,851 single cells was generated from 39 IMpassion130 PBMC pairs (29 atezo+nPac; 10 placebo [Pla]+nPac) and 35 IMpassion131 pairs (26 atezo+Pac; 9 Pla+Pac). At wk 4, atezo+nPac resulted in increased IFNα and IFNγ responses across multiple cell types (CD4+ and CD8+ T cells, B cells, NK cells and monocytes) and proliferation in NK cells, but reduced TNF signaling across multiple cell types. In contrast, 4 wks of Pla+nPac increased TNF signaling but decreased IFNα and IFNγ responses. In the presence of steroids, 4 wks of atezo+Pac also increased IFNα and IFNγ responses mainly in NK cells and monocytes, but not T cells, and reduced proliferative pathways across B and T cells and TNF signaling. Pla+Pac increased TNF signaling only in NK cells, but reduced proliferative signatures across cell types. The only on-treatment change differing significantly between atezo+nPac vs atezo+Pac was the increase in proliferation pathways in NK, T and B cells with atezo+nPac. There were no significant changes in proportions of cell subsets or TCR clonality. PBMCs from taxane-pretreated pts had higher RNA-based metabolic profile (OxPhos, DNA repair and IFNα). Taxane-naive but not taxane-pretreated immune cells had increased IFNγ and IFNα response after atezo+taxane. Conclusions: Our results suggest that atezo+taxane promotes IFNα and IFNγ responses and that steroid co-administration reduces proliferation pathways across immune cells. Prior taxane exposure was associated with an increased metabolic status, possibly rendering immune cells less sensitive to atezo-induced activation. The immune context of taxane-naive TNBC may result in more potent immune activation with atezo. Clinical trial information: NCT02425891 and NCT03125902.

Ontogeny and Vulnerabilities of Drug-Tolerant Persisters in HER2+ Breast Cancer

Resistance to targeted therapies is an important clinical problem in HER2-positive (HER2+) breast cancer. "Drug-tolerant persisters" (DTP), a subpopulation of cancer cells that survive via reversible, nongenetic mechanisms, are implicated in resistance to tyrosine kinase inhibitors (TKI) in other malignancies, but DTPs following HER2 TKI exposure have not been well characterized. We found that HER2 TKIs evoke DTPs with a luminal-like or a mesenchymal-like transcriptome. Lentiviral barcoding/single-cell RNA sequencing reveals that HER2+ breast cancer cells cycle stochastically through a "pre-DTP" state, characterized by a G0-like expression signature and enriched for diapause and/or senescence genes. Trajectory analysis/cell sorting shows that pre-DTPs preferentially yield DTPs upon HER2 TKI exposure. Cells with similar transcriptomes are present in HER2+ breast tumors and are associated with poor TKI response. Finally, biochemical experiments indicate that luminal-like DTPs survive via estrogen receptor-dependent induction of SGK3, leading to rewiring of the PI3K/AKT/mTORC1 pathway to enable AKT-independent mTORC1 activation.

SIGNIFICANCE

DTPs are implicated in resistance to anticancer therapies, but their ontogeny and vulnerabilities remain unclear. We find that HER2 TKI-DTPs emerge from stochastically arising primed cells ("pre-DTPs") that engage either of two distinct transcriptional programs upon TKI exposure. Our results provide new insights into DTP ontogeny and potential therapeutic vulnerabilities. This article is highlighted in the In This Issue feature, p. 873.

Abstract P1-08-35: Stromal tumor infiltrating lymphocytes analysis by race and ethnicity in triple negative breast cancers from 2 phase III randomized adjuvant breast cancer trials: ECOG-ACRIN E2197 and E1199

Background: Black patients with triple negative breast cancer (TNBC) have worse survival outcomes, even after adjusting for stage at diagnosis, income, insurance status and other socioeconomic factors. Little is known regarding anti-tumor immune responses in Black patients and how these differences affect responses to treatment in TNBC. Limited data exists regarding the stromal tumor infiltrating lymphocytes (sTILs, which are strongly prognostic in TNBC) distribution based on race and ethnicity. Here we evaluate the prevalence, distribution, and prognostic impact of sTILs in TNBC by race/ethnicity from 2 prospective clinical trials of adjuvant anthracycline/taxane-based chemotherapy (E2197 and E1199). Methods: Full-face hematoxylin and eosin-stained sections of 481 tumors from ECOG-ACRIN trials E2197 and E1199 were previously evaluated for density of sTILs and shown to be associated with disease-free survival (DFS), distant recurrence-free interval (DRFI), and overall survival (OS) (Adams, et al JCO 2014). Further analyses were undertaken to evaluate the impact of race/ethnicity. Results: The majority of the 481 TNBC were from White patients (82.3%, n=403); with 12.3% (n=59) Black patients, 1.6% (n=14) other (9 Hispanic, 3 Asian, 2 Other), and 0.5% (n=5) unknown race. Age distribution (mean 49.2 for White and 49.2 for Black) and node negative disease (White 68/403 (42%), Black 24/59 (41%)) were similar. However, tumor size ≤2cm was seen more commonly in White patients (34%, 137/403) compared with Black patients (20%, 12/59). Black patients had a higher proportion of high sTILs (≥30%) with 23.7% (14/59) compared to White patients (11.4%, 46/403). The association of continuous stromal TILs with DFS (hazard ratio for a 10-point difference) was 0.84 (95% CI 0.72, 0.98) for White patients and 0.94 (95% CI 0.73, 1.20) for Black patients [159 DFS events for Whites, 26 DFS events for Blacks]. Conclusions: This is the first dataset from prospective clinical trials evaluating sTILs in TNBC in Black patients. Prevalence of high sTILs was greater in Black patients compared to White patients. The association between increasing sTILs and improved invasive disease-free survival across racial/ethnic groups must be investigated in larger datasets.

Table 1.Race/EthnicityTotal (n=481)White (n=403)Black (n=59)Other (n=19)Mean age49.049.249.245.6T1 (tumor &lt;=2cm)157(32.6%)137 (34.0%)12 (20.3%)8 (42.1%)T2 (tumor &gt;2 and &lt;=5cm)283(58.8%)232 (57.6%)41 (69.5%)10 (52.6%)T3 and T441 (8.5%)34 (8.4%)6 (10.2%)1 (5.3%)Node negative197 (41.0%)168 (41.7%)24 (40.7%)5 (26.3%)Median sTILs (Quartiles)10 (10, 20)10 (10, 20)10 (10,20)20 (10, 30)sTILs = 095 (19.8%)83 (20.6%)10 (16.9%)2 (10.5%)sTILs 10-29%319 (66.3%)274 (68.0%)35 (59.3%)10 (52.6%)sTILs ≥30%67 (13.9%)46 (11.4%)14 (23.7%)7 (36.8%)—sTIL 30-49%,46 (9.6%)32 (7.9%)11 (18.6%)3 (15.8%)—sTIL 50-74%,17 (3.5%)11 (2.7%)3 (5.1%)3 (15.8%)—sTIL 75-100%4 (0.8%)3 (0.7%)01 (5.2%)iDFS (HR for 10% sTIL increase)0.86 (95% CI 0.76, 0.98)0.84 (95% CI 0.72, 0.98)0.94 (95% CI 0.73, 1.20)0.97 (95% CI 0.68, 1.40)DRFI (HR for 10% sTIL increase)0.82 (95% CI 0.68, 0.99)0.79 (95% CI 0.63, 1.00)1.08 (95% CI 0.82, 1.44)0.54 (95% CI 0.32, 0.90)OS (HR for 10% sTIL increase)0.81 (95% CI 0.69, 0.95)0.76 (95% CI 0.62, 0.94)1.01 (95% CI 0.76, 1.35)0.83 (95% CI 0.54, 1.29)

Citation Format: Natalie Klar, Robert J Gray, Sylvia Adams, Joseph A Sparano, Lori J Goldstein, Angela M DeMichele, Antonio C Wolff, Nancy E Davidson, George W Sledge, Sunil S Badve. Stromal tumor infiltrating lymphocytes analysis by race and ethnicity in triple negative breast cancers from 2 phase III randomized adjuvant breast cancer trials: ECOG-ACRIN E2197 and E1199 [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-08-35.

OUP accepted manuscript

Purpose

Provide real-world data regarding the risk for SARS-CoV-2 infection and mortality in breast cancer (BC) patients on active cancer treatment.

Methods

Clinical data were abstracted from the 3778 BC patients seen at a multisite cancer center in New York between February 1, 2020 and May 1, 2020, including patient demographics, tumor histology, cancer treatment, and SARS-CoV-2 testing results. Incidence of SARS-CoV-2 infection by treatment type (chemotherapy [CT] vs endocrine and/or HER2 directed therapy [E/H]) was compared by Inverse Probability of Treatment Weighting. In those diagnosed with SARS-CoV-2 infection, Mann–Whitney test was used to a assess risk factors for severe disease and mortality.

Results

Three thousand sixty-two patients met study inclusion criteria with 641 patients tested for SARS-COV-2 by RT-PCR or serology. Overall, 64 patients (2.1%) were diagnosed with SARS-CoV-2 infection by either serology, RT-PCR, or documented clinical diagnosis. Comparing matched patients who received chemotherapy (n = 379) with those who received non-cytotoxic therapies (n = 2343) the incidence of SARS-CoV-2 did not differ between treatment groups (weighted risk; 3.5% CT vs 2.7% E/H, P = .523). Twenty-seven patients (0.9%) expired over follow-up, with 10 deaths attributed to SARS-CoV-2 infection. Chemotherapy was not associated with increased risk for death following SARS-CoV-2 infection (weighted risk; 0.7% CT vs 0.1% E/H, P = .246). Advanced disease (stage IV), age, BMI, and Charlson’s Comorbidity Index score were associated with increased mortality following SARS-CoV-2 infection (P ≤ .05).

Conclusion

BC treatment, including chemotherapy, can be safely administered in the context of enhanced infectious precautions, and should not be withheld particularly when given for curative intent.

The tale of TILs in breast cancer: A report from The International Immuno-Oncology Biomarker Working Group

The advent of immune-checkpoint inhibitors (ICI) in modern oncology has significantly improved survival in several cancer settings. A subgroup of women with breast cancer (BC) has immunogenic infiltration of lymphocytes with expression of programmed death-ligand 1 (PD-L1). These patients may potentially benefit from ICI targeting the programmed death 1 (PD-1)/PD-L1 signaling axis. The use of tumor-infiltrating lymphocytes (TILs) as predictive and prognostic biomarkers has been under intense examination. Emerging data suggest that TILs are associated with response to both cytotoxic treatments and immunotherapy, particularly for patients with triple-negative BC. In this review from The International Immuno-Oncology Biomarker Working Group, we discuss (a) the biological understanding of TILs, (b) their analytical and clinical validity and efforts toward the clinical utility in BC, and (c) the current status of PD-L1 and TIL testing across different continents, including experiences from low-to-middle-income countries, incorporating also the view of a patient advocate. This information will help set the stage for future approaches to optimize the understanding and clinical utilization of TIL analysis in patients with BC.

PD-L1 Immunohistochemistry Assay Comparison in Atezolizumab Plus nab-Paclitaxel-Treated Advanced Triple-Negative Breast Cancer

BACKGROUND

In the phase III IMpassion130 study, atezolizumab plus nab-paclitaxel (A+nP) showed clinical benefit in advanced or metastatic triple-negative breast cancer patients who were programmed death-ligand 1 (PD-L1)+ (tumor-infiltrating immune cells [IC] ≥1%) using the SP142 immunohistochemistry assay. Here we evaluate 2 other PD-L1 assays for analytical concordance with SP142 and patient-associated clinical outcomes.

METHODS

Samples from 614 patients (68.1% of intention-to-treat population) were centrally evaluated by immunohistochemistry for PD-L1 status on IC (VENTANA SP142, SP263, Dako 22C3) or as a combined positive score (CPS; 22C3).

RESULTS

Using SP142, SP263, and 22C3 assays, PD-L1 IC ≥1% prevalence was 46.4% (95% confidence interval [CI] = 42.5% to 50.4%), 74.9% (95% CI = 71.5% to 78.3%), and 73.1% (95% CI = 69.6% to 76.6%), respectively; 80.9% were 22C3 CPS ≥1. At IC ≥1% (+), the analytical concordance between SP142 and SP263 and 22C3 was 69.2% and 68.7%, respectively. Almost all SP142+ cases were captured by other assays (double positive), but several SP263+ (29.6%) or 22C3+ (29.0%) cases were SP142- (single positive). A+nP clinical activity vs placebo+nP in SP263+ and 22C3+ patients (progression-free survival [PFS] hazard ratios [HRs] = 0.64 to 0.68; overall survival [OS] HRs = 0.75 to 0.79) was driven by double-positive cases (PFS HRs = 0.60 to 0.61; OS HRs = 0.71 to 0.75) rather than single-positive cases (PFS HRs = 0.68 to 0.81; OS HRs = 0.87 to 0.95). Concordance for harmonized cutoffs for SP263 (IC ≥4%) and 22C3 (CPS ≥10) to SP142 (IC ≥1%) was subpar (approximately 75%).

CONCLUSIONS

22C3 and SP263 assays identified more patients as PD-L1+ (IC ≥1%) than SP142. No inter-assay analytical equivalency was observed. Consistent improved A+nP efficacy was captured by the SP142 PD-L1 IC ≥1% subgroup nested within 22C3 and SP263 PD-L1+ (IC ≥1%) populations.

The consequences of hyperphagia in people with Prader-Willi Syndrome: A systematic review of studies of morbidity and mortality

Prader-Willi Syndrome (PWS) is a multi-system genetically determined neurodevelopmental disorder and the commonest cause of syndromal obesity. The development of hyperphagia in early childhood is part of the phenotype arising as a result of an impaired neural response to food intake and the inability to regulate food intake in line with energy needs. Severe obesity develops if access to food is not controlled. In this review we evaluate the evidence for increased morbidity and mortality in PWS in order to establish the extent to which it is directly related to the obesity; a consequence of the eating behaviour itself independent of obesity; or associated with other characteristics of the syndrome. Medline, Cochrane, PsychINFO, CINAHL, Web of Science and Scopus databases were used to systematically identify published material on PWS and hyperphagia and syndrome-related morbidity and mortality. One hundred and ten key papers were selected. Data on 500 people with PWS indicated that the average age of death was 21 years and obesity was, as expected, a significant factor. However, the behaviour of hyperphagia itself, independent of obesity, was also important, associated with choking, gastric rupture, and/or respiratory illness. Other syndrome-related factors increased the risk for, and seriousness of, co-morbid illness or accidents. We conclude that improving life-expectancy largely depends on managing the immediate non-obesity and obesity-related consequences of the hyperphagia, through improved support. The development of new treatments that significantly reduce the drive to eat are likely to decrease morbidity and mortality improving quality of life and life expectancy.

A Multicenter Phase II Trial of Ipilimumab and Nivolumab in Unresectable or Metastatic Metaplastic Breast Cancer: Cohort 36 of Dual Anti-CTLA-4 and Anti-PD-1 Blockade in Rare Tumors (DART, SWOG S1609)

PURPOSE

Metaplastic breast cancer (MpBC) is a rare aggressive subtype that responds poorly to cytotoxics. Median survival is approximately eight months for metastatic disease. We report results for advanced MpBC treated with ipilimumab+nivolumab, a cohort of S1609 for rare cancers (DART: NCT02834013).

METHODS

Prospective, open-label, multicenter phase II (two-stage) trial of ipilimumab (1mg/kg IV q6weeks) plus nivolumab (240mg IV q2weeks) for advanced MpBC. Primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS) and toxicity.

RESULTS

Overall, 17 evaluable patients enrolled. Median age was 60 years (26-85); median number of prior therapy lines, 2 (0-5). ORR was 18%; 3/17 patients achieved objective responses (1 complete, 2 partial responses) (2 spindle cell, 1 chondromyxoid histology), which are ongoing at 28+, 33+ and 34+ months, respectively. Median PFS and OS were 2 and 12 months, respectively. Altogether, 11 patients (65%) experienced adverse events (AEs), including one grade 5 AE. Eight patients (47%) developed an immune-related AE (irAE); with adrenal insufficiency observed in all three responders. Responses occurred in tumors with low tumor mutational burden, low PD-L1 and absent TILs.

CONCLUSION

The ipilimumab and nivolumab combination showed no new safety signals and met its primary endpoint with 18% ORR in advanced, chemotherapy-refractory MpBC. All responses are ongoing at >2 to almost 3 years later. The effect of ipilimumab and nivolumab was associated with exceptional responses in a subset of patients versus no activity. This combination warrants further investigation in MpBC, with special attention to understanding mechanism of action, and carefully designed to weigh against the significant risks of irAEs.

A position statement and practical guide to the use of particulate filtering facepiece respirators (N95, FFP2, or equivalent) for South African health workers exposed to respiratory pathogens including Mycobacterium tuberculosis and SARS-CoV-2

SUMMARY

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is transmitted mainly by aerosol in particles <10 µm that can remain suspended for hours before being inhaled. Because particulate filtering facepiece respirators ('respirators'; e.g. N95 masks) are more effective than surgical masks against bio-aerosols, many international organisations now recommend that health workers (HWs) wear a respirator when caring for individuals who may have COVID-19. In South Africa (SA), however, surgical masks are still recommended for the routine care of individuals with possible or confirmed COVID-19, with respirators reserved for so-called aerosol-generating procedures. In contrast, SA guidelines do recommend respirators for routine care of individuals with possible or confirmed tuberculosis (TB), which is also transmitted via aerosol. In health facilities in SA, distinguishing between TB and COVID-19 is challenging without examination and investigation, both of which may expose HWs to potentially infectious individuals. Symptom-based triage has limited utility in defining risk. Indeed, significant proportions of individuals with COVID-19 and/or pulmonary TB may not have symptoms and/or test negative. The prevalence of undiagnosed respiratory disease is therefore likely significant in many general clinical areas (e.g. waiting areas). Moreover, a proportion of HWs are HIV-positive and are at increased risk of severe COVID-19 and death.

RECOMMENDATIONS

Sustained improvements in infection prevention and control (IPC) require reorganisation of systems to prioritise HW and patient safety. While this will take time, it is unacceptable to leave HWs exposed until such changes are made. We propose that the SA health system adopts a target of 'zero harm', aiming to eliminate transmission of respiratory pathogens to all individuals in every healthcare setting. Accordingly, we recommend: the use of respirators by all staff (clinical and non-clinical) during activities that involve contact or sharing air in indoor spaces with individuals who: (i) have not yet been clinically evaluated; or (ii) are thought or known to have TB and/or COVID-19 or other potentially harmful respiratory infections;the use of respirators that meet national and international manufacturing standards;evaluation of all respirators, at the least, by qualitative fit testing; andthe use of respirators as part of a 'package of care' in line with international IPC recommendations. We recognise that this will be challenging, not least due to global and national shortages of personal protective equipment (PPE). SA national policy around respiratory protective equipment enables a robust framework for manufacture and quality control and has been supported by local manufacturers and the Department of Trade, Industry and Competition. Respirator manufacturers should explore adaptations to improve comfort and reduce barriers to communication. Structural changes are needed urgently to improve the safety of health facilities: persistent advocacy and research around potential systems change remain essential.

505 Failed Femoral Nail with Significant Operative Technical Difficulty: A Practical Solution to Achieve Metalwork Extraction Using Conical Screw Remover

Introduction

There is a greater risk of delayed healing and revision surgery in atypical femoral fractures (AFFs). Although non-union in reamed intra-medullary (IM) nailing is relatively uncommon, it can lead to fracture of the nail and present a considerable challenge to the treating surgeon.

Case Report

We present a case of AFF treated with IM nail fixation. Metalwork failure of the nail prompted removal of distal locking screws and plating of the fracture site at 8 months. Failure of the plate-bone interface 3 months later led to further revision surgery to remove the broken metalwork. We focus on the significant operative difficulty encountered during removal of the failed IM metalwork and provide a novel practical solution to overcome this particular challenge - insertion of a conical cannulated screw remover under fluoroscopy guidance to create an interference fit with the distal segment of the broken nail.

Discussion

This case is an example of significant and unexpected intra-operative technical difficulty, requiring improvisation and teamwork to manage. We introduce an accessible and uncomplicated alternative to the existing techniques for removal of a broken femoral nail and in doing so hope to benefit peers and colleagues should they encounter similar difficulties in the future.

Activating a collaborative innate-adaptive immune response to control metastasis

Tumor-associated macrophages (TAMs) promote metastasis and inhibit T cells, but macrophages can be polarized to kill cancer cells. Macrophage polarization could thus be a strategy for controlling cancer. We show that macrophages from metastatic pleural effusions of breast cancer patients can be polarized to kill cancer cells with monophosphoryl lipid A (MPLA) and interferon (IFN) γ. MPLA + IFNγ injected intratumorally or intraperitoneally reduces primary tumor growth and metastasis in breast cancer mouse models, suppresses metastasis, and enhances chemotherapy response in an ovarian cancer model. Both macrophages and T cells are critical for the treatment's anti-metastatic effects. MPLA + IFNγ stimulates type I IFN signaling, reprograms CD206⁺ TAMs to inducible NO synthase (iNOS)⁺ macrophages, and activates cytotoxic T cells through macrophage-secreted interleukin-12 (IL-12) and tumor necrosis factor alpha (TNFα). MPLA and IFNγ are used individually in clinical practice and together represent a previously unexplored approach for engaging a systemic anti-tumor immune response.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of breast cancer

Breast cancer has historically been a disease for which immunotherapy was largely unavailable. Recently, the use of immune checkpoint inhibitors (ICIs) in combination with chemotherapy for the treatment of advanced/metastatic triple-negative breast cancer (TNBC) has demonstrated efficacy, including longer progression-free survival and increased overall survival in subsets of patients. Based on clinical benefit in randomized trials, ICIs in combination with chemotherapy for the treatment of some patients with advanced/metastatic TNBC have been approved by the United States (US) Food and Drug Administration (FDA), expanding options for patients. Ongoing questions remain, however, about the optimal chemotherapy backbone for immunotherapy, appropriate biomarker-based selection of patients for treatment, the optimal strategy for immunotherapy treatment in earlier stage disease, and potential use in histological subtypes other than TNBC. To provide guidance to the oncology community on these and other important concerns, the Society for Immunotherapy of Cancer (SITC) convened a multidisciplinary panel of experts to develop a clinical practice guideline (CPG). The expert panel drew upon the published literature as well as their clinical experience to develop recommendations for healthcare professionals on these important aspects of immunotherapeutic treatment for breast cancer, including diagnostic testing, treatment planning, immune-related adverse events (irAEs), and patient quality of life (QOL) considerations. The evidence-based and consensus-based recommendations in this CPG are intended to give guidance to cancer care providers treating patients with breast cancer.

The journey of tumor-infiltrating lymphocytes as a biomarker in breast cancer: clinical utility in an era of checkpoint inhibition

In 2014, we described a method to quantify percentage of tumor-infiltrating lymphocytes (TILs) on hematoxylin and eosin-stained slides of breast cancer samples using light microscopy that could be performed easily by pathologists with no extra stains. The aim of detailing the method was to facilitate independent research groups replicating our prognostic findings using TIL quantity in early-stage breast cancers. A global working group of breast pathologists was convened to standardize, test reproducibility, and refine the method. A website was also established which allowed free training (www.tilsinbreastcancer.org). As a result of this work, TIL data have been collected in over 20 000 primary breast cancer samples worldwide and the robust associations with better prognoses in triple-negative breast cancer (TNBC) and HER2+ BC have been confirmed. This has resulted in the inclusion of the TIL biomarker in several international breast cancer guidelines as well as in national criteria for routine pathology reporting. TIL therefore represents the first biological prognostic biomarker for early-stage TNBCs, and here its prognostic effect is linear, with values of 30%-50% being suggested as suitable for use in potential chemotherapy de-escalation studies. The efficacy of immune checkpoint-targeted agents in breast cancer now provides direct evidence that host immune responses can modify tumor growth in some patients. With the recent granting of accelerated approvals for the first PD-1/PD-L1 targeting agents in early and advanced TNBC, our focus has now moved to investigating the clinical utility of TIL in the setting of immune checkpoint agents, with or without PD-L1 protein assessment. Emerging data suggest that TIL quantity can help clinicians identify patients with breast cancer who benefit most from PD-1/PD-L1 inhibition. In patients with advanced TNBC and HER2+ disease a TIL cut-off of 5% or 10%, with PD-L1 expression can define 'immune-enriched' tumors and currently seems to have the most clinical relevance in this context.

A case report of COVID-19 in an asymptomatic patient with newly diagnosed breast cancer

COVID-19 can be especially dangerous in vulnerable populations such as those with cancer undergoing treatment. When it is discovered in an asymptomatic patient through imaging, there is a paucity of evidence-based treatment recommendations.

The tumor microenvironment (TME) and atezolizumab + nab-paclitaxel (A+nP) activity in metastatic triple-negative breast cancer (mTNBC): IMpassion130

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Background: IMpassion130 was the first randomized phase 3 study to show clinical benefit of cancer immunotherapy (CIT) in untreated PD-L1+ mTNBC. Enhanced A + nP efficacy vs placebo (P) + nP was seen in pts with a richer immune TME but was confined to PD-L1 IC+ pts (PD-L1–expressing immune cells on ≥1% of tumor area; Emens JNCI 2021). While TNBC molecular subtyping and CD8 localization are prognostic in early TNBC, it is unknown whether these features are associated with CIT benefit in mTNBC. This exploratory analysis aimed to identify TME components associated with A + nP efficacy in IMpassion130. Methods: IHC was used to assess PD-L1 status (VENTANA SP142) and immune phenotypes (inflamed/excluded/desert per CD8 stromal/intratumoral localization; Mariathasan Nature 2018). RNA-seq was used for molecular subtyping (Burstein CCR 2015) and pathway analyses (MSigDB Hallmark). Cox regression was used to compare PFS/OS between A + nP vs P + nP, adjusted for prior taxanes, liver mets. Results: Sample classification and PD-L1 distribution are shown (Table). Improved PFS with A + nP vs P + nP was seen in PD-L1 IC+ inflamed and excluded tumors, but improved OS was limited to PD-L1 IC+ inflamed tumors. PD-L1 IC+ basal-like immune activated (BLIA) and immune suppressed (BLIS) subgroups derived PFS benefit, but OS benefit was limited to PD-L1 IC+ BLIA subgroups. In PD-L1 IC+ pts, pathway analysis identified proliferation/DNA damage repair (basal-like tumor features) and angiogenesis/ER response (higher in luminal androgen receptor [LAR]/ mesenchymal [MES] tumors) were associated with improved and reduced PFS, respectively. Conclusions: PD-L1 IC+ immune-inflamed tumors and PD-L1 IC+ BLIA tumors show highest CIT sensitivity, and LAR tumors may be resistant to CIT. These data warrant further study and validation. Clinical trial information: NCT02425891 .[Table: see text]

Risk for SARS-CoV-2 infection in patients with breast cancer treated with chemotherapy, biologic therapy or active surveillance: Patient outcomes from multicenter institution in New York

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Background: In high-risk estrogen-receptor positive, HER2 positive, or triple negative breast cancer (BC), chemotherapy can increase cure rates in early-stage disease and prolong survival in setting of advanced disease. Real world data specific to BC is needed to counsel patients (pts) with BC on their risk for SARS-CoV-2 infection and mortality in the context of the SARS-CoV-2 pandemic. Methods: In this retrospective study, we abstracted clinical data including demographics, tumor histology, cancer treatment, and COVID-19 testing results status from the electronic medical record of 3778 BC patients who received cancer care from 02/01/2020 – 05/01/2020 in New York City at our cancer center. The primary endpoint of the study was incidence of SARS-CoV-2 infection by treatment type (cytotoxic chemotherapy (CT) vs non-cytotoxic therapies (endocrine and/or HER2 directed therapy (E/H)) diagnosed by either serology, RT-PCR, or documented clinical diagnosis. Probability of Treatment Weighting (IPTW) and Mann-Whitney Test were used to assess risk of SARS-CoV-2 infection by treatment and assess outcomes based on oncologic and non-oncologic risk factors respectively. Results: 3062 patients met inclusion criteria with 379 pts in CT, 2343 pts in E/H and 340 in NT groups. During study period 641 patients (20.9%) were tested by either PCR or serology with 64 patients (2.1%) diagnosed with COVID-19. All pts who tested positive by PCR and subsequently had serology testing were positive for IgG. The weighted risk of SARS-COV-2 infection was 3.5% in CT vs. 2.7% in E/H (p=0.523). 27 patients (0.9%) expired over follow up, with 10 deaths attributed to SARS-CoV-2 infection. The weighted risk for death was 0.7% with CT vs. 0.1% with E/H, p=0.24 (Table A). Age, BMI,CCI and advanced cancer stage were associated with increased mortality following SARS-CoV-2 infection (Table). Conclusions: CT was not associated with increased risk of infection with SARS-CoV-2 infection or death following infection. BC cancer treatment, including CT, can be safely administered with enhanced infectious precautions and should not be withheld particularly when given for curative intent.[Table: see text]

Trial in progress: A phase 1, multicenter, open-label, dose-exploration and dose-expansion study evaluating the safety, tolerability, pharmacokinetics, and efficacy of AMG650 in subjects with advanced solid tumors

TPS5600

Background: KIF18A is a mitotic kinesin motor protein that regulates chromosome positioning during cell division and is overexpressed in a subset of human cancers. TP53 mutant unstable aneuploid cancer cells with chromosomal instability (CIN) features are dependent on KIF18A motor activity to prevent lethal multipolar cell division. Preclinical data demonstrate that treatment with AMG 650; an oral, first in class, selective small molecule inhibitor of KIF18A may be safe and tolerable. We are conducting a first-in-human phase 1 study with AMG 650 in adult subjects with locally advanced or metastatic solid tumors with TP53MUT, triple negative breast cancer (TNBC), high grade serous ovarian cancer (HGSOC) or serous like endometrial cancers and other solid tumors. Methods: In this phase 1, multicentric, dose escalation and dose expansion study we evaluate the safety and tolerability of AMG 650 monotherapy in patients with advanced/metastatic solid tumors (NCT04293094). The main objective is to determine the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D) based on emerging safety, efficacy, and pharmacodynamics (PD) data prior to reaching the MTD. Key inclusion criteria include the presence of measurable disease and diagnosis of advanced/metastatic triple negative breast cancer (TNBC), high-grade serous ovarian cancer (HGSOC), serous-like endometrial cancer or other solid tumors with documented TP53 mutations. In the dose expansion phase, participants with locally advanced or metastatic TNBC or HGSOC will be treated with the preliminary RP2D identified from the dose exploration part of the study. Primary endpoints include the incidence of Dose Limiting Toxicities (DLTs),Treatment-Emergent Adverse Events (TEAEs), Serious Adverse Events (SAEs), Treatment-related Adverse Events and the evaluation of the number of participants who experience a clinically significant change from baseline in vital signs, electrocardiogram and laboratory tests parameters. Secondary endpoints include Objective Response Rate, Duration of Response, Progression-free Survival, Clinical Benefit Rate, Time to Response, Time to Progression, Overall Survival (OS), Maximum Plasma Concentration (Cmax) of AMG 650, Time to Maximum Plasma Concentration (Tmax) of AMG 650 as well as Area Under the Plasma Concentration-time Curve (AUC) Over the Dosing Interval for AMG 650. Continuous monitoring of toxicity is conducted. The study began enrolling pts in March 2020 and is ongoing. For more information, please contact Amgen Medical Information: medinfo@amgen.com Clinical trial information: NCT04293094.

Abstract PD14-07: Association between biomarkers and response to pembrolizumab in patients with metastatic triple-negative breast cancer (mTNBC): Exploratory analysis from KEYNOTE-086

Background: In the phase 2 KEYNOTE-086 study (NCT02447003), pembrolizumab monotherapy had durable antitumor activity in a subset of patients with previously treated mTNBC (cohort A; n = 170) and in patients with previously untreated PD-L1-positive mTNBC (cohort B; n = 84). In this exploratory analysis of KEYNOTE-086, we evaluated the association between several biomarkers and response to pembrolizumab. Methods: Cohort A enrolled patients regardless of PD-L1 expression who had documented disease progression following ≥1 systemic therapy for metastatic disease. Cohort B enrolled patients with PD-L1-positive (combined positive score [CPS] ≥1) tumors who had not received prior systemic therapy for metastatic disease. Immunohistochemistry was used to measure PD-L1 CPS and CD8 density; H&E staining for percentage of stromal tumor infiltrating lymphocytes (sTILs); RNA-sequencing for 18-gene T-cell-inflamed gene expression profile (GEP), angiogenesis, and glycolysis signatures; and whole exome sequencing (paired tumor and germline) for TMB (TMB-H defined as ≥175 mut/exome), HRD-LOH (DNA damage), Signature 3, and APOBEC. Biomarkers were analyzed as continuous variables in cohorts A and B combined and individually. Area under the receiver operating characteristic curve was estimated between each biomarker and overall response rate (ORR). Wald test P-values were calculated using logistic regression adjusted for cohort and Eastern Cooperative Oncology Group performance status. Germline and somatic BRCA1/2 mutations were pooled; one-sided P-value was calculated using Fisher’s exact test. Spearman’s correlation was used for correlations. Results: Biomarker data were available in the following number of patients: 253 (99.6%; PD-L1), 204 (80.3%; CD8), 187 (73.6%; GEP), 171 (67.3%; TMB/HRD), 228 (89.8%; sTILs), 163 (64.2%; Signature 3/APOBEC), and 132 (52.0%; angiogenesis/glycolysis). When data from cohorts A and B were combined, PD-L1 CPS (median 2; IQR 0-10), CD8 (median 159; IQR 62-319), GEP (median -0.34; IQR -0.57 to -0.11), TMB (median 82 mut/exome; IQR 50-139), and sTILs (median 5; IQR 2-20) were significantly associated with ORR (Table). There were moderate correlations between PD-L1 and GEP (r = 0.532), PD-L1 and sTILs (r = 0.451), and GEP and sTILs (r = 0.490). No correlation was observed between TMB and PD-L1 (r = 0.038), GEP (r = -0.035), and sTILs (r = -0.031). When cohorts were combined, TMB was significantly associated with ORR, PFS, and OS after adjustment for PD-L1, GEP, CD8, or sTILs. HRD-LOH score, Signature 3, and APOBEC were not significantly associated with ORR (Table); P for BRCA1/2 was 0.2385. The angiogenesis signature was associated with lack of response while the glycolysis signature was associated with response to pembrolizumab (Table). Conclusions: In this exploratory biomarker analysis from KEYNOTE-086, higher levels of PD-L1, GEP, TMB, CD8 IHC, sTILs, and the glycolysis signature were associated with increased response to pembrolizumab monotherapy. These findings may help identify patients with mTNBC who are most likely to respond to pembrolizumab.

Table. Association of Biomarkers as Continuous Variables With Pembrolizumab Objective ResponseBiomarkerCombined Cohorts AUCCombined Cohorts P*Combined Cohorts Multitest corrected PCohort A AUCCohort B AUCPD-L10.6740.040-0.5440.654GEP0.7480.003-0.8370.561TMB0.6270.007-0.5480.710CD8 IHC0.760.000020.000120.850.68sTILs0.6710.012-0.6320.641HRD0.3940.874-0.5220.316Signature 30.6830.072-0.6970.736APOBEC0.5280.537-0.6740.623Angiogenesis0.6770.0090.0450.6610.731Glycolysis0.6120.0090.0360.8590.459AUC, area under the curve.*One-sided P-values are shown for all biomarkers except for Signature 3 and APOBEC, for which 2-sided P-values are shown.

Citation Format: Sherene Loi, Peter Schmid, Javier Cortes, David W. Cescon, Eric P. Winer, Deborah L. Toppmeyer, Hope S. Rugo, Michelino De Laurentiis, Rita Nanda, Hiroji Iwata, Ahmad Awada, Antoinette R. Tan, Roberto Salgado, Vassiliki Karantza, Petar Jelinic, Anran Wang, Lingkang Huang, Razvan Cristescu, Lakshman Annamalai, Jennifer Yearley, Jennifer Yearley, Sylvia Adams. Association between biomarkers and response to pembrolizumab in patients with metastatic triple-negative breast cancer (mTNBC): Exploratory analysis from KEYNOTE-086 [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 PD14-07.

Abstract PD14-05: Genomic profiling and clinical outcomes with first-line atezolizumab and nab-paclitaxel in triple-negative breast cancer: An exploratory analysis from the phase 3 IMpassion130 trial

Background: The clinical implications of genomic alterations in metastatic triple-negative breast cancer (mTNBC) have not been clearly addressed. In IMpassion130, atezolizumab (A) + nab-paclitaxel (nP) showed improved progression-free survival (PFS) and clinically meaningful overall survival (OS) benefit vs placebo (P) + nP in PD-L1+ mTNBC (Schmid, NEJM 2018). The goal of this exploratory study was to evaluate the prevalence of genomic alterations and their relationship with PD-L1 status and to determine whether a prognostic or predictive role for these factors exists for A + nP in a randomized dataset. Methods: Primary or metastatic tumor samples from patients in the IMpassion130 biomarker-evaluable population (BEP) were centrally evaluated for short variants (SV), copy number alteration (CNA) and rearrangements by using a targeted next-generation sequencing (NGS) panel (FoundationOne). PD-L1 status was evaluated using the VENTANA SP142 assay, with PD-L1 positivity defined by PD-L1-expressing immune cells on ≥1% of tumor area. Prognostic effects of genomic alterations were evaluated in the pooled population from both treatment arms. PFS and OS (co-primary endpoints) were analyzed by Cox proportional hazards models. ClinicalTrials.gov identifier: NCT02425891. Results: The BEP comprised 614 patients (68% of intent-to-treat population), 605 of whom received treatment. The most common pathogenic alterations were found in the following genes: TP53 (SV, 85%), MYC (CNA, 21%), PIK3CA (SV, 18%), PTEN (SV/CNA, 18%), RB1 (SV, 7%) and BRCA1 (SV, 9%). Primary tumors (n = 419), compared with metastatic tumors (n = 195), were more likely to bear alterations in BRCA1 (11.9% vs 5.6%) and less likely to have PIK3R1 alterations (4.8% vs 9.2%). TP53 loss-of-function mutations were associated with PD-L1+ status, whereas amplifications in VEGFA and CCND3 genes were significantly less associated; none of these alterations were linked with clinical outcomes favoring A + nP. Loss of RB1 (frequency 5%) was linked with reduced PFS and OS prognosis independent of treatment (hazard ratio [HR], 2.09 [95% CI: 1.42, 3.07] and HR, 1.98 [1.26, 3.11]), respectively), and CNA in CDKN2A (12%) and CDKN2B (11%) were associated with improved PFS and OS clinical activity in the A + nP arm vs the P + nP arm (HR PFS, 0.43-0.44 and HR OS, 0.47, respectively). Three of 584 microsatellite-evaluable samples (0.5%) had MSI-H status, which was not associated with PD-L1 status; all 3 MSI-H patients were from the P + nP arm. A total of 220 of 514 evaluable samples (42.8%) had PIK3CA/AKT1/PTEN-altered status, which was not significantly associated with PD-L1 status or A + nP clinical outcome. Conclusions: In this exploratory analysis using a targeted NGS panel, we show that tumors from patients with previously untreated mTNBC had similar genomic profiles at baseline as those published for early TNBC tumors. The few alterations that were linked to PD-L1 status were not linked to clinical outcome. CNA in cell cycle genes (e.g., RB1) had potential prognostic value, whereas CDKN2A and CDKN2B were potentially predictive of A + nP clinical benefit favoring A + nP. These data are hypothesis generating and require validation in an independent data set.

Citation Format: Leisha Emens, Luciana Molinero, Sylvia Adams, Hope S. Rugo, Andreas Schneeweiss, Véronique Diéras, Hiroji Iwata, Carlos Barrios, Eric P. Winer, Ching-Wei Chang, Stephen Y. Chui, Peter Schmid, Sherene Loi. Genomic profiling and clinical outcomes with first-line atezolizumab and nab-paclitaxel in triple-negative breast cancer: An exploratory analysis from the phase 3 IMpassion130 trial [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 PD14-05.

Atezolizumab and nab-Paclitaxel in Advanced Triple-Negative Breast Cancer: Biomarker Evaluation of the IMpassion130 Study

BACKGROUND

Understanding the impact of the tumor immune microenvironment and BRCA1/2-related DNA repair deficiencies on the clinical activity of immune checkpoint inhibitors may help optimize both patient and treatment selection in metastatic triple-negative breast cancer. In this substudy from the phase 3 IMpassion130 trial, immune biomarkers and BRCA1/2 alterations were evaluated for association with clinical benefit with atezolizumab and nab-paclitaxel (A+nP) vs placebo and nP in unresectable (P+nP) locally advanced or metastatic triple-negative breast cancer.

METHODS

Patients were randomly assigned 1:1 to nab-paclitaxel 100 mg/m2 (days 1, 8, and 15 of a 28-day cycle) and atezolizumab 840 mg every 2 weeks or placebo until progression or toxicity. Progression-free survival and overall survival were evaluated based on programmed death-ligand 1 (PD-L1) expression on immune cells (IC) and tumor cells, intratumoral CD8, stromal tumor-infiltrating lymphocytes, and BRCA1/2 mutations.

RESULTS

PD-L1 IC+ in either primary or metastatic tumor tissue was linked to progression-free survival and overall survival benefit with A+nP. PD-L1 IC+ low (26.9%; 243 of 902 patients) and high (13.9%; 125 of 902 patients) populations had improved outcomes that were comparable. Intratumoral CD8 and stromal tumor-infiltrating lymphocytes positivity (sTIL+) were associated with PD-L1 IC+ status; improved outcomes were observed with A+nP vs P+nP only in CD8+ and sTIL+ patients who were also PD-L1 IC+. BRCA1/2 mutations (occurring in 14.5% [89 of 612 patients]) were not associated with PD-L1 IC status, and PD-L1 IC+ patients benefited from A+nP regardless of BRCA1/2 mutation status.

CONCLUSIONS

Although A+nP was more efficacious in patients with richer tumor immune microenvironment, clinical benefit was only observed in patients whose tumors were PD-L1 IC+.

Serial single-cell profiling analysis of metastatic TNBC during Nab-paclitaxel and pembrolizumab treatment

PURPOSE

Immunotherapy has recently been shown to improve outcomes for advanced PD-L1-positive triple-negative breast cancer (TNBC) in the Impassion130 trial, leading to FDA approval of the first immune checkpoint inhibitor in combination with taxane chemotherapy. To further develop predictive biomarkers and improve therapeutic efficacy of the combination, interrogation of the tumor immune microenvironment before therapy as well as during each component of treatment is crucial. Here we use single-cell RNA sequencing (scRNA-seq) on tumor biopsies to assess immune cell changes from two patients with advanced TNBC treated in a prospective trial at predefined serial time points, before treatment, on taxane chemotherapy and on chemo-immunotherapy.

METHODS

Both patients (one responder and one progressor) received the trial therapy, in cycle 1 nab-paclitaxel given as single agent, in cycle 2 nab-paclitaxel in combination with pembrolizumab. Tumor core biopsies were obtained at baseline, 3 weeks (after cycle 1, chemotherapy alone) and 6 weeks (after cycle 2, chemo-immunotherapy). Single-cell RNA sequencing (scRNA-seq) of both cancer cells and infiltrating immune cells isolated were performed from fresh tumor core biopsy specimens by 10 × chromium sequencing.

RESULTS

ScRNA-seq analysis showed significant baseline heterogeneity of tumor-infiltrating immune cell populations between the two patients as well as modulation of the tumor microenvironment by chemotherapy and immunotherapy. In the responding patient there was a population of PD-1high-expressing T cells which significantly decreased after nab-paclitaxel plus pembrolizumab treatment as well as a presence of tissue-resident memory T cells (TRM). In contrast, tumors from the patient with rapid disease progression showed a prevalent and persistent myeloid compartment.

CONCLUSIONS

Our study provides a deep cellular analysis of on-treatment changes during chemo-immunotherapy for advanced TNBC, demonstrating not only feasibility of single-cell analyses on serial tumor biopsies but also the heterogeneity of TNBC and differences in on-treatment changes in responder versus progressor.

Hyperactive CDK2 Activity in Basal-like Breast Cancer Imposes a Genome Integrity Liability that Can Be Exploited by Targeting DNA Polymerase ε

Knowledge of fundamental differences between breast cancer subtypes has driven therapeutic advances; however, basal-like breast cancer (BLBC) remains clinically intractable. Because BLBC exhibits alterations in DNA repair enzymes and cell-cycle checkpoints, elucidation of factors enabling the genomic instability present in this subtype has the potential to reveal novel anti-cancer strategies. Here, we demonstrate that BLBC is especially sensitive to suppression of iron-sulfur cluster (ISC) biosynthesis and identify DNA polymerase epsilon (POLE) as an ISC-containing protein that underlies this phenotype. In BLBC cells, POLE suppression leads to replication fork stalling, DNA damage, and a senescence-like state or cell death. In contrast, luminal breast cancer and non-transformed mammary cells maintain viability upon POLE suppression but become dependent upon an ATR/CHK1/CDC25A/CDK2 DNA damage response axis. We find that CDK1/2 targets exhibit hyperphosphorylation selectively in BLBC tumors, indicating that CDK2 hyperactivity is a genome integrity vulnerability exploitable by targeting POLE.

Management of perianal abscesses in infants without general anaesthesia: a systematic review of the literature

Perianal abscesses are a common surgical presentation in infants. Historically, general anaesthesia (GA) has been used to facilitate incision and drainage, with or without exploration for a fistula-in-ano (FIA). This review aims to assess outcomes following management of perianal abscesses without GA in infants less than 24 months old. We aim to identify the success of management without GA. Using PRISMA guidelines, studies were identified from MEDLINE, EMBASE and PubMed. Studies including infants less than 24 months with perianal abscesses managed without GA were reviewed. The primary outcome was the number of patients requiring GA following initial management without GA. Secondary outcomes included rates of recurrent perianal abscesses, rates of progression to FIA and time to cure. Nine studies, involving 1049 infants less than 24 months old met inclusion criteria. A total of 1039 (99.0%) were males. Study design consisted of one prospective case series of 18 patients, and eight retrospective cohort studies. There were no randomized control trials. A total of 1037 (98.9%) patients were initially managed without GA. Of these, 59 (5.6%) were documented to subsequently require a general anaesthetic. Treatment modalities included antibiotics, regular baths, needle aspiration, incision and drainage under local anaesthesia, hainosankyuto and fibroblast growth factor. A total of 790 (75.3%) healed primarily without further intervention. A total of 243 (23.2%) were documented to have a recurrence or progression to FIA. All patients who required a subsequent general anaesthetic had progressed to FIA. Despite the lack of well-designed prospective studies, existing evidence supports management of perianal abscesses without initial GA in infants, with more than 75% healing completely. Further research aimed at standardizing care and confirming the safety and efficacy of initial non-operative management are warranted, and may potentially reduce the number of unnecessary initial and subsequent clinical interventions.