NKG2A Is a Therapeutic Vulnerability in Immunotherapy Resistant MHC-I Heterogeneous Triple-Negative Breast Cancer

Despite the success of immune checkpoint inhibition (ICI) in treating cancer, patients with triple-negative breast cancer (TNBC) often develop resistance to therapy, and the underlying mechanisms are unclear. MHC-I expression is essential for antigen presentation and T-cell-directed immunotherapy responses. This study demonstrates that TNBC patients display intratumor heterogeneity in regional MHC-I expression. In murine models, loss of MHC-I negates antitumor immunity and ICI response, whereas intratumor MHC-I heterogeneity leads to increased infiltration of natural killer (NK) cells in an IFNγ-dependent manner. Using spatial technologies, MHC-I heterogeneity is associated with clinical resistance to anti-programmed death (PD) L1 therapy and increased NK:T-cell ratios in human breast tumors. MHC-I heterogeneous tumors require NKG2A to suppress NK-cell function. Combining anti-NKG2A and anti-PD-L1 therapies restores complete response in heterogeneous MHC-I murine models, dependent on the presence of activated, tumor-infiltrating NK and CD8+ T cells. These results suggest that similar strategies may enhance patient benefit in clinical trials.

SIGNIFICANCE

Clinical resistance to immunotherapy is common in breast cancer, and many patients will likely require combination therapy to maximize immunotherapeutic benefit. This study demonstrates that heterogeneous MHC-I expression drives resistance to anti-PD-L1 therapy and exposes NKG2A on NK cells as a target to overcome resistance. This article is featured in Selected Articles from This Issue, p. 201.

Atezolizumab in Combination With Carboplatin and Survival Outcomes in Patients With Metastatic Triple-Negative Breast Cancer: The TBCRC 043 Phase 2 Randomized Clinical Trial

Importance

Agents targeting programmed death ligand 1 (PD-L1) have demonstrated efficacy in triple-negative breast cancer (TNBC) when combined with chemotherapy and are now the standard of care in patients with PD-L1-positive metastatic disease. In contrast to microtubule-targeting agents, the effect of combining platinum compounds with programmed cell death 1 (PD-1)/PD-L1 immunotherapy has not been extensively determined.

Objective

To evaluate the efficacy of atezolizumab with carboplatin in patients with metastatic TNBC.

Design, Setting, and Participants

This phase 2 randomized clinical trial was conducted in 6 centers from August 2017 to June 2021.

Interventions

Patients with metastatic TNBC were randomized to receive carboplatin area under the curve (AUC) 6 alone or with atezolizumab, 1200 mg, every 3 weeks until disease progression or unacceptable toxic effects with a 3-year duration of follow-up.

Main Outcome and Measures

The primary end point was investigator-assessed progression-free survival (PFS). Secondary end points included overall response rate (ORR), clinical benefit rate (CBR), and overall survival (OS). Other objectives included correlation of response with tumor PD-L1 levels, tumor-infiltrating lymphocytes (TILs), tumor DNA- and RNA-sequenced biomarkers, TNBC subtyping, and multiplex analyses of immune markers.

Results

All 106 patients with metastatic TNBC who were enrolled were female with a mean (range) age of 55 (27-79) years, of which 12 (19%) identified as African American/Black, 1 (1%) as Asian, 73 (69%) as White, and 11 (10%) as unknown. Patients were randomized and received either carboplatin (n = 50) or carboplatin and atezolizumab (n = 56). The combination improved PFS (hazard ratio [HR], 0.66; 95% CI, 0.44-1.01; P = .05) from a median of 2.2 to 4.1 months, increased ORR from 8.0% (95% CI, 3.2%-18.8%) to 30.4% (95% CI, 19.9%-43.3%), increased CBR at 6 months from 18.0% (95% CI, 9.8%-30.1%) to 37.5% (95% CI, 26.0%-50.6%), and improved OS (HR, 0.60; 95% CI, 0.37-0.96; P = .03) from a median of 8.6 to 12.6 months. Subgroup analysis showed PD-L1-positive tumors did not benefit more from adding atezolizumab (HR, 0.62; 95% CI, 0.23-1.65; P = .35). Patients with high TILs (HR, 0.12; 95% CI, 0.30-0.50), high mutation burden (HR, 0.50; 95% CI, 0.23-1.06), and prior chemotherapy (HR, 0.59; 95% CI, 0.36-0.95) received greater benefit on the combination. Patients with obesity and patients with more than 125 mg/dL on-treatment blood glucose levels were associated with better PFS (HR, 0.35; 95% CI, 0.10-1.80) on the combination. TNBC subtypes benefited from adding atezolizumab, except the luminal androgen receptor subtype.

Conclusions and Relevance

In this randomized clinical trial, the addition of atezolizumab to carboplatin significantly improved survival of patients with metastatic TNBC regardless of PD-L1 status. Further, lower risk of disease progression was associated with increased TILs, higher mutation burden, obesity, and uncontrolled blood glucose levels.

Trial Registration

ClinicalTrials.gov Identifier: NCT03206203.

Spatial and Compositional Biomarkers in Tumor Microenvironment Predicts Clinical Outcomes in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited treatment options, which warrants identification of novel therapeutic targets. Deciphering nuances in the tumor microenvironment (TME) may unveil insightful links between anti-tumor immunity and clinical outcomes, yet such connections remain underexplored. Here we employed a dataset derived from imaging mass cytometry of 58 TNBC patient specimens at single-cell resolution and performed in-depth quantifications with a suite of multi-scale computational algorithms. We detected distinct cell distribution patterns among clinical subgroups, potentially stemming from different infiltration related to tumor vasculature and fibroblast heterogeneity. Spatial analysis also identified ten recurrent cellular neighborhoods (CNs) - a collection of local TME characteristics with unique cell components. Coupling of the prevalence of pan-immune and perivasculature immune hotspot CNs, enrichment of inter-CN interactions was associated with improved survival. Using a deep learning model trained on engineered spatial data, we can with high accuracy (mean AUC of 5-fold cross-validation = 0.71) how a separate cohort of patients in the NeoTRIP clinical trial will respond to treatment based on baseline TME features. These data reinforce that the TME architecture is structured in cellular compositions, spatial organizations, vasculature biology, and molecular profiles, and suggest novel imaging-based biomarkers for treatment development in the context of TNBC.

Feasibility of Symptom Monitoring During the First Year of Endocrine Therapy for Early Breast Cancer Using Patient-Reported Outcomes Collected via Smartphone App

PURPOSE

Treatment-associated symptoms drive early discontinuation of adjuvant endocrine therapy (ET) for breast cancer. We hypothesized that symptom monitoring with electronic patient-reported outcomes (ePROs) during adjuvant ET will enhance symptom detection, symptom management, and persistence.

METHODS

Eligible patients were initiating ET for stage 0-III breast cancer. Participants completed ePRO surveys via smartphone at baseline and 1, 3, 6, and 12 months. Measures included Patient-Reported Outcomes Measurement Information System Anxiety, Depression, Fatigue, and Vaginal Discomfort; plus Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events items assessing joint pain, hot flashes, vaginal dryness, concentration problems, and memory problems. Scores surpassing prespecified thresholds triggered alerts, and recommended symptom management pathways were provided to clinicians. The primary objective was to evaluate feasibility, assessed by survey completion rates, with targets of >65% for the baseline survey and ≥1 follow-up survey during the first 6 months. Secondary objectives included 12-month ET discontinuation rate (target: ≤15%), describing symptoms and evaluating pathway implementation.

RESULTS

Among 250 participants, 73.2% completed the baseline survey and 69.6% completed ≥1 follow-up survey during the first 6 months. Thirty-one percent of participants had ≥1 symptom alert at baseline and 74% had ≥1 symptom alert during follow-up. The proportions of participants for whom pathway-concordant symptom management was documented at each time point ranged from 12.8% to 36.6%. Twenty-eight participants (11.2%) discontinued ET by 12 months.

CONCLUSION

Symptom monitoring with ePROs during adjuvant ET is feasible. Despite infrequent documentation of pathway-concordant symptom management after symptom alerts, ePROs were associated with favorable short-term ET persistence.

The PD-1- and LAG-3-targeting bispecific molecule tebotelimab in solid tumors and hematologic cancers: a phase 1 trial

Tebotelimab, a bispecific PD-1×LAG-3 DART molecule that blocks both PD-1 and LAG-3, was investigated for clinical safety and activity in a phase 1 dose-escalation and cohort-expansion clinical trial in patients with solid tumors or hematologic malignancies and disease progression on previous treatment. Primary endpoints were safety and maximum tolerated dose of tebotelimab when administered as a single agent (n = 269) or in combination with the anti-HER2 antibody margetuximab (n = 84). Secondary endpoints included anti-tumor activity. In patients with advanced cancer treated with tebotelimab monotherapy, 68% (184/269) experienced treatment-related adverse events (TRAEs; 22% were grade ≥3). No maximum tolerated dose was defined; the recommended phase 2 dose (RP2D) was 600 mg once every 2 weeks. There were tumor decreases in 34% (59/172) of response-evaluable patients in the dose-escalation cohorts, with objective responses in multiple solid tumor types, including PD-1-refractory disease, and in LAG-3+ non-Hodgkin lymphomas, including CAR-T refractory disease. To enhance potential anti-tumor responses, we tested margetuximab plus tebotelimab. In patients with HER2+ tumors treated with tebotelimab plus margetuximab, 74% (62/84) had TRAEs (17% were grade ≥3). The RP2D was 600 mg once every 3 weeks. The confirmed objective response rate in these patients was 19% (14/72), including responses in patients typically not responsive to anti-HER2/anti-PD-1 combination therapy. ClinicalTrials.gov identifier: NCT03219268 .

A transcriptome-informed QSP model of metastatic triple-negative breast cancer identifies predictive biomarkers for PD-1 inhibition

Triple-negative breast cancer (TNBC), a highly metastatic breast cancer subtype, has limited treatment options. While a small number of patients attain clinical benefit with single-agent checkpoint inhibitors, identifying these patients before the therapy remains challenging. Here, we developed a transcriptome-informed quantitative systems pharmacology model of metastatic TNBC by integrating heterogenous metastatic tumors. In silico clinical trial with an anti-PD-1 drug, pembrolizumab, predicted that several features, such as the density of antigen-presenting cells, the fraction of cytotoxic T cells in lymph nodes, and the richness of cancer clones in tumors, could serve individually as biomarkers but had a higher predictive power as combinations of two biomarkers. We showed that PD-1 inhibition neither consistently enhanced all antitumorigenic factors nor suppressed all protumorigenic factors but ultimately reduced the tumor carrying capacity. Collectively, our predictions suggest several candidate biomarkers that might effectively predict the response to pembrolizumab monotherapy and potential therapeutic targets to develop treatment strategies for metastatic TNBC.

A Phase II Single-arm Study of Palbociclib in Patients With HER2-positive Breast Cancer With Brain Metastases and Analysis of ctDNA in Patients With Active Brain Metastases

INTRODUCTION

Palbociclib is highly efficacious and well tolerated in hormone-receptor positive (HR+) metastatic breast cancer (BC) but its activity for HER2+ BC with brain metastases (BM) is unknown.

METHODS

In a single-arm phase II study we evaluated palbociclib with trastuzumab for patients with HER2+ MBC and BM. The primary endpoint was BM response rate. Circulating tumor DNA (ctDNA) was evaluated at baseline, and in a subset of patients at cycle 3 and progression. We also retrospectively identified additional patients with metastatic BC, active BM, and a ctDNA assessment prior to therapy for BM.

RESULTS

Twelve patients with HER2+ MBC were enrolled, 4 with HR+ and 8 with HR- disease. No responses were seen. Best response was stable disease for 6 patients and progressive disease for 6 patients. The median PFS was 2.2 months, interquartile range (IQR) was 1.56 to 3.63 months. The median OS was 13.1 months and IQR was 9.4 to 23.8 months The CNS was the primary site of progression for all patients. The median variant allele fraction (VAF) of the dominant variant in each patient was 0.18% (interquartile range [IQR] 0.12%-0.47%) with a median number of somatic alterations of 1. We additionally evaluated ctDNA results from 26 patients with BC and active BM, among whom the median VAF was 11.8% (IQR 3.9%-27.3%) with a median number of alterations was 6 (IQR 4-9). Notably, progressive systemic disease was significantly less frequent in the trial cohort compared with additional retrospectively identified patients (8% vs. 81%).

CONCLUSION

Palbociclib did not demonstrate activity in HER2+ MBC with BM. Patients with progressive BM but stable, responding, or absent systemic disease have low VAF and number of alterations detected by ctDNA analysis from blood.

Exceptional responses to PARP inhibitors in patients with metastatic breast cancer in oncologic crisis

PURPOSE

Cancers deficient in homologous recombination DNA repair, such as those with BRCA1 or BRCA2 (BRCA1/2) mutations rely on a pathway mediated by the enzyme poly(adenosine diphosphate-ribose) polymerase (PARP). PARP inhibitors (PARPi's) have demonstrated efficacy in treating patients with germline (g)BRCA1/2, somatic (s)BRCA1/2, and gPALB2 mutations in clinical trials. However, patients with a poor performance status (PS) and those with severe organ impairment are often excluded from clinical trials and cancer-directed treatment.

METHODS

We report the cases of two patients with metastatic breast cancer who had poor PS, significant visceral disease, and gPALB2 and sBRCA mutations, who derived significant clinical benefit from treatment with PARP inhibition.

RESULTS

Patient A had germline testing demonstrating a heterozygous PALB2 pathogenic mutation (c.3323delA) and a BRCA2 variant of unknown significance (c.9353T>C), and tumor sequencing revealed PALB2 (c.228_229del and c.3323del) and ESR1 (c.1610A>C) mutations. Patient B was negative for pathologic BRCA mutations upon germline testing, but tumor sequencing demonstrated somatic BRCA2 copy number loss and a PIK3CA mutation (c.1633G>A). Treatment with PARPi's in these two patients with an initial PS of 3-4 and significant visceral disease resulted in prolonged clinical benefit.

CONCLUSION

Patients with a poor PS, such as those described here, may still have meaningful clinical responses to cancer treatments targeting oncogenic drivers. More studies evaluating PARPi's beyond gBRCA1/2 mutations and in sub-optimal PS would help identify patients who may benefit from these therapies.

A randomized phase 2 study of neoadjuvant carboplatin and paclitaxel with or without atezolizumab in triple negative breast cancer (TNBC) - NCI 10013

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

The tumor microenvironment and triple-negative breast cancer aggressiveness: shedding light on mechanisms and targeting

INTRODUCTION

In contrast to other breast cancer subtypes, there are currently limited options of targeted therapies for triple-negative breast cancer (TNBC). Immense research has demonstrated that not only cancer cells but also stromal cells and immune cells in the tumor microenvironment (TME) play significant roles in the progression of TNBC. It is thus critical to understand the components of the TME of TNBC and the interactions between the various cell populations.

AREAS COVERED

The components of the TME of TNBC identified by single-cell technologies are reviewed. Furthermore, the molecular interactions between the cells and the potential therapeutic targets contributing to the progression of TNBC are discussed.

EXPERT OPINION

Single-cell omics studies have contributed to the classification of cells in the TME and the identification of important cell types involved in the progression and the treatment of the tumor. The interactions between cancer cells and stromal cells/immune cells in the TME have led to the discovery of potential therapeutic targets. Experimental data with spatial and temporal resolution will further boost the understanding of the TME of TNBC.

Dynamics of tumor-associated macrophages in a quantitative systems pharmacology model of immunotherapy in triple-negative breast cancer

Quantitative systems pharmacology (QSP) modeling is an emerging mechanistic computational approach that couples drug pharmacokinetics/pharmacodynamics and the course of disease progression. It has begun to play important roles in drug development for complex diseases such as cancer, including triple-negative breast cancer (TNBC). The combination of the anti-PD-L1 antibody atezolizumab and nab-paclitaxel has shown clinical activity in advanced TNBC with PD-L1-positive tumor-infiltrating immune cells. As tumor-associated macrophages (TAMs) serve as major contributors to the immuno-suppressive tumor microenvironment, we incorporated the dynamics of TAMs into our previously published QSP model to investigate their impact on cancer treatment. We show that through proper calibration, the model captures the macrophage heterogeneity in the tumor microenvironment while maintaining its predictive power of the trial results at the population level. Despite its high mechanistic complexity, the modularized QSP platform can be readily reproduced, expanded for new species of interest, and applied in clinical trial simulation.

•

A mechanistic model of quantitative systems pharmacology in immuno-oncology

•

Dynamics of tumor-associated macrophages are integrated into our previous work

•

Conducting in silico clinical trials to predict clinical response to cancer therapy

Integrating Immunotherapy in Early-Stage Triple-Negative Breast Cancer: Practical Evidence-Based Considerations

The KEYNOTE-522 study is a practice-changing phase III randomized study that demonstrated that the addition of pembrolizumab to polychemotherapy improves outcomes in patients with high-risk early-stage triple-negative breast cancer (TNBC). This regimen is highly efficacious with unprecedented pathologic complete response (pCR) rates, and clinically meaningful improvements in event-free survival (EFS). However, the combination is also associated with significant high-grade treatment-related toxicity. The backbone regimen deviated from common practice, including the addition of carboplatin, lack of dose dense anthracyclines, and adjuvant capecitabine for residual disease, thus brining important questions regarding real-world translation of these results. This brief report practically addresses some of the most relevant questions physicians and patients face in optimizing care using the best available evidence.

Using ecological momentary assessment to understand associations between daily physical activity and symptoms in breast cancer patients undergoing chemotherapy

PURPOSE

Understanding real-time relationships between physical activity (PA) and symptoms during chemotherapy (CT) could have important implications for intervention. This study used ecological momentary assessment to examine the relationship between objective PA and symptoms during CT.

METHODS

Breast cancers patients (n = 67; M_age = 48.6 (SD = 10.3)) participated in data collection at three time points during CT: beginning, middle, and end. At each time point, participants answered four prompts assessing symptoms and wore an accelerometer for 10 days (3 days pre-CT, day of CT, and 6 days post-CT). Multilevel linear regression models examined the between- and within-person associations between moderate to vigorous (MVPA) and light-intensity physical activity (LPA) and same and next-day symptom ratings controlling for covariates.

RESULTS

On days when individuals engaged in more LPA or MVPA, separately, they reported improved affect, anxiety, fatigue, physical functioning (walking and activities of daily living), pain, and cognition that day (p < 0.001 for all). Findings were consistent for next-day symptom ratings with the exception that only previous day LPA was related to next-day fatigue and neither LPA nor MVPA were related to next-day cognition (p < 0.001 for all). No between-person effects were found.

CONCLUSIONS

Within person higher than usual PA on a given day, regardless of intensity, is associated with improved symptoms ratings on the current and next day.

IMPLICATIONS FOR CANCER SURVIVORS

Encouraging breast cancer patients undergoing CT to engage in daily PA could help manage CT-associated symptoms.

Abstract P2-08-15: Clinical, pathologic, and molecular associations of tumor mutational burden in metastatic breast cancer

Background: Tumor mutational burden (TMB) is a biomarker approved to predict response to immune checkpoint blockade (ICB) in solid tumors irrespective of their tissue of origin. However, there are limited data in patients with breast cancer and high TMB to support the use of ICB. The goal of this analysis is to describe clinical, pathological and molecular associations with TMB within a cohort of patients with metastatic breast cancer. Methods: We included patients enrolled onto an ongoing prospective study titled Individualized Molecular Analyses Guide Efforts (IMAGE)-II. Patients eligible for IMAGE-II have metastatic breast cancer of any subtype that had progressed on at least one standard-of-care therapy. Genetic profiling of tumor tissue was performed at the discretion of the treating team using one of several commercially available next generation sequencing platforms. For purposes of this analysis, only patients who underwent tissue-based Foundation Medicine analysis are included as TMB assessments are different across different platforms. Data are summarized by descriptive statistics. Linear and logistic regression analyses are conducted to evaluate the association between TMB and other clinical, pathological and molecular factors. We will present data on associations with specific mutations (i.e. ESR1, ERBB2, DNA repair, Pi3K signaling, TP53) and ctDNA TMB at a later time. Results:Of 117 patients in the IMAGE-II database, median age was 57 (range 23-86), 65% were White, 29% Black, and 6% Other. TMB data were available on 62 patients. Of those with both TMB and subtype information, 35 (70%) had ER+HER2- tumors, and 15 (30%) had ER-HER2- tumors. Median TMB was 4 mutations/megabase and ranged from 0 to 27. We did not observe significant differences in TMB in patients with ER+HER2- and those with ER-HER2- tumors (median TMB of 4 [0-27] and 5 [1-25], respectively), nor between White versus Black patients (median TMB of 4 [0-27] and 5 [0-12], respectively). However, we did observe that age was positively associated with higher TMB (p-value = 0.02). Additionally, we observed that the time between metastatic diagnosis and TMB measurement was positively associated with TMB (p-value &lt; 0.01); this significant association was also observed in ER+HER2- patients (p-value &lt; 0.01) but not in ER-HER2- patients. Median time to obtaining TMB since metastatic diagnosis was 1.1 (range -0.8 - 12.8) years. More lines of chemotherapy prior to TMB assessment was not observed to be associated with higher TMB. Conclusions: We observed that TMB was higher in patients who have had a longer disease course. Further research is required to understand changes in TMB over time, and how TMB is correlated with. other genomic and tumor microenvironment characteristics. A deeper understanding of TMB may help refine it as a predictive biomarker for ICB.

Citation Format: Mohamed A Mohamed, Chenghuang Wang, Morgan Buckley, Jennifer Lehman, Jenna Canzoniero, Christopher D Gocke, Raquel Nunes, Ben Ho Park, Karen L Smith, Jessica Tao, Hanna Tukachinsky, Mary Wilkinson, Antonio C Wolff, Vered Stearns, Cesar A Santa-Maria. Clinical, pathologic, and molecular associations of tumor mutational burden in metastatic breast cancer [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 P2-08-15.

Pembrolizumab for patients with leptomeningeal metastasis from solid tumors: efficacy, safety, and cerebrospinal fluid biomarkers

Background

The benefit of immune checkpoint inhibitors (ICIs) in patients with leptomeningeal metastases (LMM) is unknown.

Methods

We undertook a phase II trial of pembrolizumab in patients with LMM from solid tumors. Eligible patients had radiologic/cytologic LMM and Eastern Cooperative Oncology Group performance status 0–1. Pembrolizumab was administered intravenously at 200 mg q3W until disease progression/unacceptable toxicity. The primary endpoint was central nervous system (CNS) response after four cycles, defined radiologically/cytologically/clinically. Serial cerebrospinal fluid (CSF) was assessed for tumor-derived DNA (t-DNA) aneuploidy and cytokines.

Results

Thirteen of a planned 16 patients were treated between April 2017 and December 2019. The study closed early for poor accrual. Median age was 57 years (range: 22–79). Sixty-two percent of patients had tumors not traditionally ICI-responsive (hormone-receptor (HR)-positive breast carcinoma=39%; high-grade glioma=23%), while 38% had ICI-responsive tumors (non-small cell lung cancer (NSCLC)=23%, head and neck carcinoma=8%, cutaneous squamous carcinoma (CSC)=8%). CNS response was observed in 38% of patients at 12 weeks (95% CI 13.9% to 68.4%) by pre-defined criteria and LM-RANO, and 2 achieved durable complete responses (CSC=1, overall survival (OS) 3+ years; NSCLC=1, OS 9 months). Median CNS progression-free survival and OS was 2.9 months (95% CI 1.3 to NR) and 4.9 months (95% CI 3.7 to NR), respectively. Grade 3+ treatment-related adverse events occurred in 15% of patients. Sensitivity for LMM detection by t-DNA and cytopathology was 84.6% (95% CI 54.6% to 98.1%) and 53.9% (95% CI 25.1% to 80.8%), respectively. Pre-therapy and on-therapy CSF cytokine analysis demonstrated complete responders clustered together.

Conclusions

Pembrolizumab conferred a 38% CNS response rate in patients with LMM, a tolerable safety profile, and deep responses in selected patients with ICI-responsive tumors. CSF t-DNA may be sensitive for LMM detection, and immunologic subsets of CNS response warrant further study.

Trial registration number

NCT03091478

Landmark trials in the medical oncology management of metastatic breast cancer

Significant advances in the management of metastatic breast cancer (MBC) have guided more personalized treatment according to disease biology and led to improved survival outcomes and quality of life for patients. In this review, we discuss landmark clinical trials in medical oncology that have shaped the current standard of care for MBC. Combinations of endocrine therapy with cyclin-dependent kinase 4/6 inhibitors have led to substantial improvements in overall survival, thus becoming standard first-line treatment for patients with HR-positive MBC. Inhibition of the PI3K and mTOR pathway is another promising strategy to overcome resistance to endocrine therapy. HER2-targeted therapies have also evolved with the addition of pertuzumab to trastuzumab plus a taxane demonstrating remarkable overall survival advantage in patient with HER2-positive MBC. In second or later line therapies, novel anti-HER2 antibody-drug conjugates and TKIs have durable antitumor activity, survival benefit, and encouraging efficacy in the subgroup of patients with brain metastases. Triple negative breast cancer remains the most challenging subtype due to lack of druggable targets. Immunotherapy for patients with PDL-1 expression on tumor infiltrating immune cells and poly (ADP-ribose) polymerase inhibitors for those with germline BRCA1/2 mutations are the latest approved targeted strategies in this population. Numerous obstacles still exist in treating MBC, especially for patients whose disease develops resistance to available agents. Future research is eagerly awaited to address the optimal sequence or combination of therapies and to identify better biomarkers to guide precision medicine.

The impact of weight loss on physical function and symptoms in overweight or obese breast cancer survivors: results from POWER-remote

PURPOSE

In pre-planned observational analysis of the POWER-remote trial, we examined the impact of weight loss on patient-reported outcomes (PROs). We hypothesized a priori that survivors with ≥ 5% weight loss would have improved physical function (PF) at 6 months vs. those who did not.

METHODS

Patients with stage 0-III breast cancer who completed local therapy and chemotherapy with BMI ≥ 25 kg/m² were randomized to POWER-remote (telephone coaching; diet/activity tracking) or self-directed weight loss (booklet). Participants completed PROs at baseline, 6, and 12 months: PROMIS PF, pain, fatigue, anxiety, depression, sleep; FACT-endocrine symptoms; MOS-sexual function. Changes in PROs among those with ≥ 5% weight loss vs. those with < 5% were tested with multivariable mixed effect models, across randomized groups.

RESULTS

Of 94 women who completed PROs, 84 and 69 participants were evaluable at 6 and 12 months, respectively. Regardless of intervention, PF improved in those with ≥ 5% weight loss vs. those with < 5% at 6 months (4.4 vs. 0.3 points; p = 0.02) and 12 months (3.6 vs. 0 points; p = 0.04). While endocrine symptoms, fatigue, and anxiety improved at 6 months in those who lost ≥ 5%, differences were not significant vs. those who lost < 5%. There was no significant change within or between groups in sexual function, depression, or sleep. Findings at 12 months were similar, except pain improved in those losing ≥ 5%.

CONCLUSIONS

These results support the benefits of weight loss in overweight/obese breast cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

Weight management in breast cancer survivors may improve PF.

Abstract PD14-09: Nci 10013 - A randomized phase 2 study of neoadjuvant carboplatin and paclitaxel, with or without atezolizumab in triple negative breast cancer (TNBC)

Background Inhibition of PD-L1 with atezolizumab combined with chemotherapy has shown acceptable safety and improved survival in patients with metastatic PD-L1 positive triple negative breast cancer (TNBC). Patients with TNBC who do not achieve a pathological complete response (pCR) to neoadjuvant chemotherapy have a high risk of disease recurrence and death. This randomized, open-label, phase 2 trial evaluates neoadjuvant carboplatin and paclitaxel with or without atezolizumab in patients with previously untreated clinical stages II and III TNBC. Methods Women aged ≥18 years with clinical stage T2-T4c, any N, M0 primary tumor by AJCC 7th edition staging TNBC; ECOG PS 0-2; and no prior systemic therapy for the indexed breast cancer were eligible. Patients were randomized in a 1:2 ratio to carboplatin AUC5 q 3 weeks x 4 + paclitaxel 80 mg/m2 q week x 12 (Arm A), or carboplatin AUC5 q 3 weeks x 4 + paclitaxel 80 mg/m2 q week x 12 + atezolizumab 1200 mg q3 weeks x 4 (Arm B). Surgery was 3-6 weeks following neoadjuvant chemotherapy. Adjuvant dose-dense doxorubicin and cyclophosphamide was administered q2 weeks with growth factor support to all patients as per routine care. pCR and tumor infiltrating lymphocyte (TIL) percentages are the co-primary endpoints. pCR-evaluable population includes all eligible women who have been randomized and received at least one dose of combination therapy, while the TIL-evaluable population includes all eligible women who have evaluable TIL percentage after one cycle of therapy. A sample size of 67 (22 in Arm A, and 45 in Arm B) provided 80% power at 1-sided alpha = 0.10 to detect a minimum of 15% difference in TIL and 29% improvement (40% vs. 69%) in pCR, respectively. Herein, we report pCR results in the per protocol modified intent-to-treat population (mITT), which includes all eligible patients who were randomized and received at least one dose of combination therapy. Results Sixty-seven patients were randomized between 8/2017 and 9/2019. Six patients randomized to Arm A withdrew consent; 2 of these received protocol therapy but are excluded from the mITT analyses as they are not evaluable because definitive pathology reports are not available. Median follow up is 6 months (range 0.3 - 12.6 months). Median age is 52 years (range 25 - 78). Forty-three (64.2%) were Caucasian and thirteen (19.4%) were African American. Twenty-five (37.3%) were pre-menopausal. 67.2% and 32.8% had stages II and III disease respectively. Nine (13.4%) had a germline mutation in either BRCA1 or BRCA2. In the mITT population, 3 of 16 patients achieved pCR in Arm A - 18.8% (95% CI 4.0%- 45.6%), versus 25 of 45 patients in Arm B - 55.6% (95% CI 40.0%-70.4%); p value 0.018. pCR in those with BRCA mutations was 50% and 80% in Arm A and Arm B, respectively. Treatment delays were observed in 9 patients (40.9%) in Arm A, and 20 (44.4%) in Arm B; dose reductions occurred in 4 patients (18.1%) in Arm A, and in 6 (13.3%) in Arm B. There were 4 SAEs in Arm A and 10 in Arm B. One patient in Arm B had grade 3 adrenal insufficiency. One patient in Arm B died from recurrent disease during the follow-up period. Conclusions: The addition of atezolizumab to neoadjuvant carboplatin and paclitaxel resulted in an increased pCR rate in patients with clinical stages II and III TNBC. However, the pCR in the control Arm A was lower than expected, possibly due to the absence of neoadjuvant anthracyclines. The high pCR rate observed in the experimental arm of this study is similar to that observed in other neoadjuvant trials utilizing anthracyclines, taxanes, and carboplatin in TNBC. Clinical trial information: NCT02883062.

Citation Format: Foluso O Ademuyiwa, Feng Gao, Ina Chen, Donald W Northfelt, Robert Wesolowski, Mili Arora, Adam Brufsky, Claire Dees, Cesar A Santa-Maria, Roisin M Connolly, Jeremy Force, Alvaro Moreno-Aspitia, Sarah Larson, Elad Sharon, William Gillanders. Nci 10013 - A randomized phase 2 study of neoadjuvant carboplatin and paclitaxel, with or without atezolizumab in triple negative breast cancer (TNBC) [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 PD14-09.

Abstract PS9-14: Feasibility of monitoring symptoms during endocrine therapy with patient reported outcomes collected via smart phone app

Background: Despite known benefits in reducing breast cancer (BC) recurrence and death, up to 50% of patients discontinue endocrine therapy (ET) early. Symptoms are often cited as a reason for early ET discontinuation (DC). The symptom burden during ET captured by patient reported outcomes (PRO) exceeds that captured by clinicians. Methods: We initiated a single arm pilot trial evaluating symptom monitoring during ET with PRO collected via smart phone app. Eligible patients are women starting ET for stage 0-III BC. Participants receive text message reminders to complete surveys at baseline (BL), 1, 3, 6 and 12 months (mo). Participants who do not complete 2 sequential surveys may opt out of further surveys. Surveys include PROMIS measures for anxiety, depression, fatigue and the vaginal discomfort domain of sexual function plus PRO-CTCAE measures for concentration, memory, hot flashes, joint pain and vaginal dryness. PROMIS measures are scored by T-score look up tables. PRO-CTCAE responses are reported on a 5 point scale (0-4). Severe or worsening scores trigger email alerts to clinicians as follows: T-scores ≥70 or ≥5 points worse than BL for anxiety, depression, and fatigue; T-score ≥65 or ≥5 points worse than BL for sexual function; scores ≥3 or ≥2 points worse than BL on PRO-CTCAE measures. Recommended management pathways are provided to clinicians upon alert acknowledgement. The primary endpoint is feasibility, with success defined as ≥65% of participants completing the BL survey and ≥65% of participants completing ≥1 follow-up (FU) survey during the first 6 mo of ET. Secondary endpoints include patient-reported symptoms and pathway-concordant symptom management based on chart review. We report here descriptive statistics of the observed data to date and multivariate logistic regression analysis of factors associated with BL survey completion. Results: From Feb 2019 to May 2020, 213 of 250 planned participants enrolled. Median FU is 5.7 mo. Mean age is 58.3 years (SD 11.7). 154 (72.3%) participants are white (W) and 32 (15%) are black (B). 189 (88.7%) participants have stage I-II BC. Prior to initiating ET, 82 (39%) had mastectomy, 75 (35.2%) had chemotherapy and 135 (63.4%) had radiation. 138 (64.8%) initiated an aromatase inhibitor and 72 (33.8%) initiated tamoxifen. BL survey completion rate is 73.7% (95% confidence interval (CI) 67.3-79.5%). To date, 69.3% (95% CI 60.5-77.2%) of participants completed ≥1 FU survey during the first 6 mo of ET. 25.2% of participants opted out of participation within 6 mo. On multivariate analysis, race was associated with BL survey completion. By race, BL survey completion rate was: 77.9% (W) and 62.5% (B). Mean scores on PROMIS depression, anxiety, fatigue, and sexual function measures at BL, 1 mo, and 3 mo were +/- 0.5 SD of population means. Compared to BL, mean PRO-CTCAE scores for joint pain severity and hot flash frequency worsened at 1 and 3 mo and mean PRO-CTCAE score for vaginal dryness severity worsened at 3 mo (p&lt;0.05). 28% of participants had alerts at BL. Most common BL alerts were joint pain and hot flashes. To date, 79.7% of participants had ≥1 alert on a FU survey. Most common FU alerts were joint pain, hot flashes and fatigue. Median number of alerts per participant per FU survey is 1 (range 0-5). To date, clinicians acknowledged 29.8% of alerts within 7 days and made pathway-concordant management recommendations within 30 days for 39.4% of alerts. Conclusion: Monitoring symptoms during ET using PRO collected via smart phone app is feasible. Symptoms are common during ET. Updated data, including factors associated with survey completion, clinician response to alerts and the association between PRO scores and early ET DC, will be reported at the conference. These data will be used to design a randomized trial to evaluate symptom monitoring via smart phone app to reduce early ET DC.

Citation Format: Karen L Smith, Chenguang Wang, David Lim, Amanda Montanari, Raquel Nunes, Mary J. Wilkinson, Jennifer Y. Sheng, Rima Couzi, John Fetting, Carol Riley, Antonio C. Wolff, Cesar A. Santa-Maria, Katie Papathakis, Lauren Collins-Chase, Christie Hilton, Claire Snyder, Elissa Thorner, Dara Z. Ikejiani, Molly Steimer, Vered Stearns. Feasibility of monitoring symptoms during endocrine therapy with patient reported outcomes collected via smart phone app [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 PS9-14.

Abstract PD11-04: The impact of sleep on weight loss in overweight or obese breast cancer survivors

BACKGROUND: Sleep disturbance, common in cancer survivors, is associated with obesity, eating behaviors and metabolism, and may impact weight loss treatment outcomes. Weight loss promotion in breast cancer survivors is important because it can potentially decrease cancer recurrence. We have previously demonstrated the efficacy of a behavioral weight loss (BWL) intervention for overweight/obese breast cancer survivors in the POWER-remote breast cancer trial. In the current study we aimed to evaluate the impact of baseline sleep on weight outcomes at 6 and 12 months. We hypothesized that participants with poor sleep at baseline will lose significantly less weight. METHODS: Women with a history of stage 0-III breast cancer, who completed local therapy and chemotherapy, with a body mass index ≥25 kg/m2 were randomized to a self-directed approach or the 12-month POWER-remote intervention, a BWL intervention consisting of telephone-based coaching, online educational materials and tracking of diet, physical activity and weight. Participants completed demographic questionnaires at baseline, and patient-reported outcomes (PROs) at baseline, 6 and 12 months, including the 6-item NIH PROMIS Adult Sleep Disturbance Version 1.0 Short Form, assessing sleep quality, depth, and restoration over the last week. Weight was measured at baseline, 6 and 12 months and % total weight loss (%TWL) was calculated from baseline weight. Those with poor sleep were defined as having a sleep T-score &gt;55, and associations between sleep scores and change in weight at 6 and 12 months were made using a linear regression model, while adjusting for baseline weight. Fisher’s exact test was also used to compare the number of patients who had 5% weight-loss between sleep groups.

RESULTS: A total of 48 women with early stage breast cancer received BWL. Those with poor sleep in the BWL group (n= 16) lost significantly less weight than those with normal sleep in the BWL group (n=32) at both 6 (-4.06% vs -6.77% TWL, p&gt;0.05) and 12 months (-3.87% vs -7.54% TWL, p&gt;0.05), respectively. Similar findings were seen in poor sleepers in the BWL group and attaining 5% weight loss at 6 (p&gt;0.05) and 12 months (p&gt;0.05). There were no significant differences in weight loss outcomes among those in usual care.

CONCLUSION: Breast cancer survivors receiving the weight loss intervention who reported normal sleep at baseline had double the weight loss than those with sleep disturbance at 12 months (-7.54% vs -3.87%). While this is not statistically significant, it is clinically significant and leaves room for further study. These results suggest that sleep may affect weight loss. Updated data, including comparison with control group and analyses by weight loss irrespective of arm, will be reported at the conference. Further studies are need to evaluate the association between baseline sleep and weight loss, and determine if interventions that detect and treat underlying sleep disturbance may augment behavioral interventions for weight loss.

FUNDING: Breast Cancer Research Foundation, Cigarette Restitution Fund

Table 1: Weight Loss Summary in BWL group based on Sleep DisturbanceVariablesPoor sleep (T-score &gt;55)Normal sleep (T-Score &lt;55)TotalSample SizeN = 16N = 32N = 48Baseline Weight - Mean (SD)202.1 (32.26)182.64 (27.73)Weight Loss 6mo. (lbs) - Mean (SD)-8.5 (10.02)-11.58 (11.03)Weight Loss 12mo. (lbs) - Mean (SD)-7.92 (14.61)-12.63 (13.72)Percent change in weight from BL to 6mo. - Mean (SD)-4.06 (4.83)-6.77 (6.45)p&gt;0.05Percent change in weight from BL to 12mo. - Mean (SD)-3.87 (7.29)-7.54 (7.91)p&gt;0.05

Citation Format: Jennifer Y Sheng, Amanda K Montanari, Amanda L Blackford, David D Lim, Cesar A Santa-Maria, Vered Stearns, Michael T Smith, Janelle W Coughlin. The impact of sleep on weight loss in overweight or obese breast cancer survivors [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 PD11-04.

Abstract OT-13-08: A remote-directed “virtual” clinical trial in metastatic breast cancer to determine feasibility of evaluating patient response to immunotherapy using spliceosome mutational markers (SF3B1): The PRISMM trial (NCT04447651)

Background:

Next-generation sequencing (NGS) is becoming increasingly routine in patients with advanced cancers, and rare mutations may occasionally be identified. Evaluating the efficacy of targeting rare mutations is challenging given the low observed frequencies, which can result in slow accrual to clinical trials. The internet and social media have revolutionized the way we receive information and connect with each other, and may potentially be leveraged to identify patients with rare mutations. Spliceosome mutations, such as SF3B1, occur in approximately 4% of breast cancers. The Park Lab has demonstrated that somatic cell knock-in of an SF3B1 hotspot mutation results in new mRNA transcripts can be translated into aberrant proteins. These preliminary data suggest that spliceosome mutations could produce a high number of neoantigens, which may increase sensitivity to immune checkpoint inhibitors (ICI). Indeed, since response rates to immunotherapy in patients with metastatic breast cancer is low, identifying biomarkers predictive of response is critical. We therefore designed a remotely directed “virtual” clinical trial to determine the feasibility of evaluating Patient Response to Immunotherapy using Spliceosome Mutational Markers (PRISMM, NCT04447651). Methods: The is a prospective feasibility trial in which patients will be identified via a social media campaign that directs potential participants to a landing page where they can fill out an online form. Patients will need to self-identify as having metastatic breast cancer (any receptor status) with an SF3B1 mutation (main eligibility criteria); once this information is confirmed by the study team, outside records will be obtained and their case will be reviewed at an institutional Molecular Tumor Board; ICI may be recommended or not. Recommendations from the Board will be provided to the patient and local oncologist, who will then decide whether to proceed with the Board’s recommendation or not. Efficacy of next line therapy will be followed by physician and patient questionnaires every one to three months. During routine blood collection, we will evaluate plasma tumor DNA (ptDNA) and peripheral blood mononuclear cells (PBMCs) at baseline and three months. The primary objective of this study is to evaluate the feasibility of conducting a prospective study using online recruitment tools, and the feasibility of real-time case review by a centralized Molecular Tumor Board to assist in therapeutic decision making. Secondary objectives include evaluating the clinical effect of ICI including progression-free and overall survival, correlate SF3B1 mutations in ptDNA with tissue-based NGS, and describe immunopharmacodynamic changes by PBMC evaluation. We anticipate screening approximately 5000 patients via our social media campaign to identify 60 eligible patients. We will conduct efficacy interim analysis after 23, 35, 47, and 56 patients are enrolled. The response rate of 1% 5%, 10%, and 20% correspond to 99.8%, 74.7%, 24.9%, and 1.1% chance that the study will stop early with an average sample size of 26.2, 41.3, 53.6, and 58.7 patients enrolled and treated respectively. If the true response rate exceeds 15% the Board will continue to make recommendation for ICI in patients with SF3B1 mutations. For more information please contact us at PRISMM@jhmi.edu.

Citation Format: Natasha Hunter, Jeffrey Wang, Leslie Cope, Christine Hodgdon, Vered Stearns, Elizabeth Jaffee, Ben Park, Cesar A Santa-Maria. A remote-directed “virtual” clinical trial in metastatic breast cancer to determine feasibility of evaluating patient response to immunotherapy using spliceosome mutational markers (SF3B1): The PRISMM trial (NCT04447651) [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 OT-13-08.

Relationship of circulating immune cells with lifestyle factors and cancer recurrence in early-stage breast cancer

PURPOSE

To evaluate the relationship of circulating immune cells with recurrence and metabolic/lifestyle factors in patients with early-stage breast cancer.

METHODS

Patients with early-stage breast cancer were identified from the electronic record and institutional registry. Lymphocyte and monocyte counts were obtained from blood samples at time of diagnosis prior to any chemotherapy. Correlations between lymphocyte and monocyte and recurrence were assessed in the entire cohort and among obese patients, those reporting alcohol consumption and smoking. Competing risk regression was used to analyze time to recurrence.

RESULTS

A total of 950 patients with ≥ 5 years of follow-up were identified; 433 had complete data and were eligible for analysis. 293 (68%) had hormone receptor-positive breast cancer, 82 (19%) HER2 positive, and 53 (13%) triple negative. Patients in the highest quintile of lymphocytes compared to the lowest quintile had lower risk of recurrence (subhazard ratio (SHR) = 0.17, 95% CI [0.03-0.93], p = 0.041) while patients in the highest quintile of monocytes had lower risk for recurrence (SHR = 0.19, 95% CI [0.04, 0.92], p = 0.039). Higher monocytes were more strongly associated with lower recurrence among those reporting alcohol consumption (HR = 0.10, 95% CI [0.01, 0.91], p = 0.04). In obese patients, higher lymphocytes were associated with lower risk of recurrence (p = 0.046); in non-obese patients, higher monocytes were associated with lower risk of recurrence (p = 0.02). There were no correlations among patients who reported tobacco use.

CONCLUSIONS

High lymphocyte and monocyte counts are associated with lower recurrence rate in early-stage breast cancer, particularly in obese patients and those reporting alcohol consumption.

TBCRC 048: Phase II Study of Olaparib for Metastatic Breast Cancer and Mutations in Homologous Recombination-Related Genes

PURPOSE

Olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi), is approved for the treatment of human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) in germline (g)BRCA1/2 mutation carriers. Olaparib Expanded, an investigator-initiated, phase II study, assessed olaparib response in patients with MBC with somatic (s)BRCA1/2 mutations or g/s mutations in homologous recombination (HR)-related genes other than BRCA1/2.

METHODS

Eligible patients had MBC with measurable disease and germline mutations in non-BRCA1/2 HR-related genes (cohort 1) or somatic mutations in these genes or BRCA1/2 (cohort 2). Prior PARPi, platinum-refractory disease, or progression on more than two chemotherapy regimens (metastatic setting) was not allowed. Patients received olaparib 300 mg orally twice a day until progression. A single-arm, two-stage design was used. The primary endpoint was objective response rate (ORR); the null hypothesis (≤ 5% ORR) would be rejected within each cohort if there were four or more responses in 27 patients. Secondary endpoints included clinical benefit rate and progression-free survival (PFS).

RESULTS

Fifty-four patients enrolled. Seventy-six percent had estrogen receptor-positive HER2-negative disease. Eighty-seven percent had mutations in PALB2, sBRCA1/2, ATM, or CHEK2. In cohort 1, ORR was 33% (90% CI, 19% to 51%) and in cohort 2, 31% (90% CI, 15% to 49%). Confirmed responses were seen only with gPALB2 (ORR, 82%) and sBRCA1/2 (ORR, 50%) mutations. Median PFS was 13.3 months (90% CI, 12 months to not available/computable [NA]) for gPALB2 and 6.3 months (90% CI, 4.4 months to NA) for sBRCA1/2 mutation carriers. No responses were observed with ATM or CHEK2 mutations alone.

CONCLUSION

PARP inhibition is an effective treatment for patients with MBC and gPALB2 or sBRCA1/2 mutations, significantly expanding the population of patients with breast cancer likely to benefit from PARPi beyond gBRCA1/2 mutation carriers. These results emphasize the value of molecular characterization for treatment decisions in MBC.

Landmark trials in the medical oncology management of early stage breast cancer

With the advent of breast cancer screening programs, the majorities of patients with newly diagnosed breast cancer are diagnosed with early stage disease and are likely to experience cure with proper treatment. Significant advances have been made in the management of early-stage breast cancer to personalize treatment according to disease biology. This progress has led to improvement in survival outcomes and quality of life for our patients. In this review, we discuss landmark clinical trials in medical oncology that have shaped the current standard of care for early stage ER-positive, HER2-positive, and triple negative breast cancer.

Daily Physical Activity and Symptom Reporting in Breast Cancer Patients Undergoing Chemotherapy: An Intensive Longitudinal Examination

BACKGROUND

Increased activity is beneficial during chemotherapy, but treatment-related symptoms may be a barrier. This study examines the relationship between daily fluctuations in symptoms and activity during chemotherapy.

METHODS

Women undergoing chemotherapy for breast cancer [n = 67; M _age = 48.6 (SD = 10.3)] wore an accelerometer 24 hours/day and received four text prompts/day to rate symptoms for 10 consecutive days at the beginning, middle, and end of chemotherapy. Mixed-effects models were used to examine the between and within-person relationships between symptom ratings on a given day and moderate to vigorous physical activity (MVPA) and light physical activity (LPA) on that day and the following day controlling for relevant covariates and using the Bonferroni correction for multiple comparisons.

RESULTS

For MVPA and LPA, within-person associations were statistically significant for same day affect, fatigue, pain, walking, activities of daily living (ADL) physical function, and cognitive function. Previous day anxiety was associated with next day LPA. Every one point worse symptom rating than an individual's overall average was associated with: (i) between 1.49 (pain) and 4.94 (fatigue) minutes less MVPA and between 4.48 (pain) and 24.72 (ADL physical function) minutes less LPA that day, and (ii) 11.28 minutes less LPA the next day. No between-person effects were significant for MVPA or LPA.

CONCLUSIONS

Daily within-person variations in symptoms were associated with MVPA and LPA during chemotherapy for breast cancer.

IMPACT

Future work should explore relationships between symptoms and activity further and identify whether tailoring to symptoms enhances efficacy of physical activity promotion interventions during chemotherapy.

Optimizing Radiation Therapy to Boost Systemic Immune Responses in Breast Cancer: A Critical Review for Breast Radiation Oncologists

Immunotherapy using immune checkpoint blockade has revolutionized the treatment of many types of cancer. Radiation therapy (RT)-particularly when delivered at high doses using newer techniques-may be capable of generating systemic antitumor effects when combined with immunotherapy in breast cancer. These systemic effects might be due to the local immune-priming effects of RT resulting in the expansion and circulation of effector immune cells to distant sites. Although this concept merits further exploration, several challenges need to be overcome. One is an understanding of how the heterogeneity of breast cancers may relate to tumor immunogenicity. Another concerns the need to develop knowledge and expertise in delivery, sequencing, and timing of RT with immunotherapy. Clinical trials addressing these issues are under way. We here review and discuss the particular opportunities and issues regarding this topic, including the design of informative clinical and translational studies.

Circulating immune cell dynamics in patients with triple negative breast cancer treated with neoadjuvant chemotherapy

BACKGROUND

Lymphopenia has been associated with inferior cancer outcomes, but there is limited data in breast cancer. We describe the effects of neoadjuvant chemotherapy on circulating immune cells and its association with pathological complete response (pCR) rates in triple negative breast cancer (TNBC).

METHODS

We constructed a database of patients with early stage TNBC treated with neoadjuvant chemotherapy. Circulating lymphocytes and monocytes were assessed before and after neoadjuvant chemotherapy. These were correlated with pCR rates and disease-free survival (DFS) using Fisher's exact test, logistic regression, and the log-rank test.

RESULTS

From 2000 to 2015, we identified 95 eligible patients. Median age was 50; 29 (31%) were treated with platinum-containing chemotherapy; and 66 (69%) with nonplatinum-containing chemotherapy (anthracycline-taxane, or either alone). About 32 (34%) patients achieved a pCR; and 33 (35%) had recurrence events. Median follow-up time was 47 months. No significant associations were found between changes in lymphocytes and pCR or DFS. There was a correlation between lower monocyte levels after neoadjuvant chemotherapy and pCR (mean monocyte 0.56 in those with no-pCR vs 0.46 in those with pCR, P = .049, multivariate P = .078) and DFS (median DFS in highest monocyte quartile was 30 vs 107 months in lowest quartile, P = .022, multivariate P = .023). In patients who received nonplatinum regimens, DFS was better among those who had larger decreases in monocytes.

CONCLUSIONS

Development of lymphopenia from neoadjuvant chemotherapy was not associated with pCR in patients with TNBC. However, lower absolute circulating monocytes after neoadjuvant chemotherapy was associated with improved outcomes.

Management of Breast Cancer During the COVID-19 Pandemic: A Stage- and Subtype-Specific Approach

The COVID-19 pandemic has rapidly changed delivery of cancer care. Many nonurgent surgeries are delayed to preserve hospital resources, and patient visits to health care settings are limited to reduce exposure to SARS-CoV-2. Providers must carefully weigh risks and benefits of delivering immunosuppressive therapy during the pandemic. For breast cancer, a key difference is increased use of neoadjuvant systemic therapy due to deferral of many breast surgeries during the pandemic. In some cases, this necessitates increased use of genomic tumor profiling on core biopsy specimens to guide neoadjuvant therapy decisions. Breast cancer treatment during the pandemic requires multidisciplinary input and varies according to stage, tumor biology, comorbidities, age, patient preferences, and available hospital resources. We present here the Johns Hopkins Women's Malignancies Program approach to breast cancer management during the COVID-19 pandemic. We include algorithms based on tumor biology and extent of disease that guide management decisions during the pandemic. These algorithms emphasize medical oncology treatment decisions and demonstrate how we have operationalized the general treatment recommendations during the pandemic proposed by national groups, such as the COVID-19 Pandemic Breast Cancer Consortium. Our recommendations can be adapted by other institutions and medical oncology practices in accordance with local conditions and resources. Guidelines such as these will be important as we continue to balance treatment of breast cancer against risk of SARS-CoV-2 exposure and infection until approval of a vaccine.

The Effects of a Remote-based Weight Loss Program on Adipocytokines, Metabolic Markers, and Telomere Length in Breast Cancer Survivors: the POWER-Remote Trial

PURPOSE

We initiated a clinical trial to determine the proportion of breast cancer survivors achieving ≥5% weight loss using a remotely delivered weight loss intervention (POWER-remote) or a self-directed approach, and to determine the effects of the intervention on biomarkers of cancer risk including metabolism, inflammation, and telomere length.

EXPERIMENTAL DESIGN

Women with stage 0-III breast cancer, who completed local therapy and chemotherapy, with a body mass index ≥25 kg/m² were randomized to a 12-month intervention (POWER-remote) versus a self-directed approach. The primary objective was to determine the number of women who achieved at least 5% weight loss at 6 months. We assessed baseline and 6-month change in a panel of adipocytokines (adiponectin, leptin, resistin, HGF, NGF, PAI1, TNFα, MCP1, IL1β, IL6, and IL8), metabolic factors (insulin, glucose, lipids, hs-CRP), and telomere length in peripheral blood mononuclear cells.

RESULTS

From 2013 to 2015, 96 women were enrolled, and 87 were evaluable for the primary analysis; 45 to POWER-remote and 42 to self-directed. At 6 months, 51% of women randomized to POWER-remote lost ≥5% of their baseline body weight, compared with 12% in the self-directed arm [OR, 7.9; 95% confidence interval (CI), 2.6-23.9; P = 0.0003]; proportion were similar at 12 months (51% vs 17%, respectively, P = 0.003). Weight loss correlated with significant decreases in leptin, and favorable modulation of inflammatory cytokines and lipid profiles. There was no significant change in telomere length at 6 months.

CONCLUSIONS

A remotely delivered weight loss intervention resulted in significant weight loss in breast cancer survivors, and favorable effects on several biomarkers.

Abstract P3-11-03: Pilot neoadjuvant study of niraparib in HER2-negative, BRCA-mutated resectable breast cancer

Background: Niraparib is a selective poly(ADP-ribose) polymerase 1/2 inhibitor that has demonstrated antitumor activity in advanced triple-negative breast cancer (TNBC) in combination with a programmed cell death 1 inhibitor, with the greatest clinical activity seen in tumors with breast cancer susceptibility gene (BRCA) mutations. Pharmacologically, niraparib has demonstrated a wide volume of distribution and high cell membrane permeability. In breast and ovarian cancer xenograft mouse models, niraparib achieved tumor exposures that were 3.3 times greater than plasma exposure. The objective of this study is to evaluate the antitumor activity of single-agent niraparib in the neoadjuvant treatment of patients with localized, human epidermal growth factor receptor 2 (HER2)-negative, BRCA-mutated breast cancer. The relative concentration of niraparib in tumor versus plasma was also assessed. Methods: Eligible patients were ≥18 years old, with HER2-negative, BRCA-mutated (germline or somatic) resectable breast cancer with a tumor size of ≥1 cm who had not received prior treatment for the current malignancy. Patients received niraparib 200 mg once daily for 2 months. At the end of 2 months, at their treating physician’s discretion, patients proceeded directly to surgery, received additional cycles of niraparib (maximum of 6 months), or received neoadjuvant chemotherapy. The primary endpoint was tumor response rate measured by magnetic resonance imaging (MRI) after 2 months of treatment. Response was defined as a ≥30% reduction in tumor volume from baseline. Secondary endpoints included tumor response rate measured by ultrasound, quantified percent change in tumor volume measured by MRI or ultrasound, pathological complete response, and safety and tolerability. Additionally, niraparib concentrations were measured in tumor and plasma samples using qualified liquid chromatography-tandem mass spectrometry. Results: Twenty-one patients were enrolled. As of June 2019, 18 patients had both an MRI and ultrasound scan at the end of month 2 and were evaluable for response. Ten patients are currently on treatment. The median age of patients was 43 years (range, 21-73). Fourteen patients had a BRCA1 mutation, 6 patients had a BRCA2 mutation, and 1 patient had both. Fifteen patients had TNBC, and 6 patients had hormone receptor-positive disease. All 18 response-evaluable patients had a clinical response after 2 months of treatment by at least one imaging modality; no patient experienced disease progression. Tumor response rate measured by MRI after 2 months of treatment was 89% (n/N = 16/18). Results measured by ultrasound were similar, with a 94% response rate at cycle 2 (n/N = 17/18). The median percent decrease in tumor volume after 2 months of treatment was 88% (range, 26-100%) and 89% (range, 23-100%) as measured by MRI and ultrasound, respectively. In the 5 samples measured thus far, niraparib concentrations in tumor biopsies after 2 months of treatment ranged from approximately 4-131-fold higher than those in corresponding plasma samples. Efficacy and tumor concentration data for all patients will be presented at the meeting. The most common (≥10%) drug-related treatment-emergent adverse events (TEAEs) of any grade were nausea, fatigue, anemia, insomnia, and decreased appetite. The only drug-related grade ≥3 toxicity in ≥10% of patients was anemia (3 patients). Three patients had a dose reduction due to a TEAE; no patient discontinued treatment due to a TEAE. Conclusion: Niraparib was well tolerated and showed promising antitumor activity in the neoadjuvant treatment of patients with localized HER2-negative, BRCA-mutated breast cancer. Niraparib achieved 4-131-fold higher concentrations in tumor than in plasma. Clinical trial information: NCT03329937. Funding: TESARO: A GSK Company (Waltham, MA, USA) sponsored the study.

Citation Format: Hyo Han, Minetta C Liu, Erika Hamilton, Hanna Irie, Cesar A Santa-Maria, James Reeves, Andre Liem, Adrianna Milillo Naraine, Julie Nangia, David Page, Meghan Duncan, Ming Shan, Yongqiang Tang, Julie R Graham, Leif W Ellisen, Steven Isakoff, Laura Spring. Pilot neoadjuvant study of niraparib in HER2-negative, BRCA-mutated resectable breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-11-03.

Phase II study of pembrolizumab and capecitabine for triple negative and hormone receptor-positive, HER2-negative endocrine-refractory metastatic breast cancer

BACKGROUND

Response rates to single agent immune checkpoint blockade in unselected pretreated HER2-negative metastatic breast cancer (MBC) are low. However, they may be augmented when combined with chemotherapy.

METHODS

We conducted a single-arm, phase II study of patients with triple negative (TN) or hormone receptor-positive endocrine-refractory (HR+) MBC who were candidates for capecitabine. Patients were treated with pembrolizumab 200 mg intravenously day 1 and capecitabine 1000 mg/m2 by mouth twice daily on days 1-14 of a 21-day cycle. The primary end point was median progression-free survival (mPFS) compared with historic controls and secondary end points were overall response rate (ORR), safety and tolerability. The study had 80% power to detect a 2-month improvement in mPFS with the addition of pembrolizumab over historic controls treated with capecitabine alone.

RESULTS

Thirty patients, 16 TN and 14 HR+ MBC, were enrolled from 2017 to 2018. Patients had a median age of 51 years and received a median of 1 (range 0-6) prior lines of therapy for MBC. Of 29 evaluable patients, the mPFS was 4.0 (95% CI 2.0 to 6.4) months and was not significantly longer than historic controls of 3 months. The median overall survival was 15.4 (95% CI 8.2 to 20.3) months. The ORR was 14% (n=4), stable disease (SD) was 41% (n=12) and clinical benefit rate (CBR=partial response+SD>6 months) was 28% (n=8). The ORR and CBR were not significantly different between disease subtypes (ORR 13% and 14%, CBR 25% and 29% for TN and HR+, respectively). The 1-year PFS rate was 20.7% and three patients have ongoing responses. The most common adverse events were low grade and consistent with those seen in MBC patients receiving capecitabine, including hand-foot syndrome, gastrointestinal symptoms, fatigue and cytopenias. Toxicities at least possibly from pembrolizumab included grade 3 or 4 liver test abnormalities (7%), rash (7%) and diarrhea (3%), as well as grade 5 hepatic failure in a patient with liver metastases.

CONCLUSIONS

Compared with historical controls, pembrolizumab with capecitabine did not improve PFS in this biomarker unselected, pretreated cohort. However, some patients had prolonged disease control.

TRIAL REGISTRATION NUMBER

NCT03044730.

Immune Checkpoint Inhibitor Therapy in Breast Cancer

Initial studies investigating single-agent activity of immune checkpoint inhibitors (ICIs) serve as proof of principle that harnessing the immune system can have anticancer activity in a variety of human malignancies. Although breast cancer was historically believed to be immunogenically silent, early studies indicate overall response rates with ICIs are similar to those observed with many other solid malignancies. Overall response rates in advanced breast cancer are low, but the responses are remarkably durable. A deeper understanding of the biology of the interaction between cancer and immune cells is required to both develop biomarkers that more accurately predict response to therapy and identify effective immunotherapy-based combination strategies that can enhance the immunogenicity of biologically "cold" tumors. Breast cancer encompasses a variety of diseases defined by the presence or absence of central oncogenic drivers, and early data suggest that the distinct subtypes may have unique immune phenotypes. Breast cancer represents an ideal disease in which to investigate immunotherapeutic strategies given the prevalence of the disease, unique clinical trial design opportunities, and immunophenotypic diversity.

In silico simulation of a clinical trial with anti-CTLA-4 and anti-PD-L1 immunotherapies in metastatic breast cancer using a systems pharmacology model

The low response rate of immune checkpoint blockade in breast cancer has highlighted the need for predictive biomarkers to identify responders. While a number of clinical trials are ongoing, testing all possible combinations is not feasible. In this study, a quantitative systems pharmacology model is built to integrate immune-cancer cell interactions in patients with breast cancer, including central, peripheral, tumour-draining lymph node (TDLN) and tumour compartments. The model can describe the immune suppression and evasion in both TDLN and the tumour microenvironment due to checkpoint expression, and mimic the tumour response to checkpoint blockade therapy. We investigate the relationship between the tumour response to checkpoint blockade therapy and composite tumour burden, PD-L1 expression and antigen intensity, including their individual and combined effects on the immune system, using model-based simulations. The proposed model demonstrates the potential to make predictions of tumour response of individual patients given sufficient clinical measurements, and provides a platform that can be further adapted to other types of immunotherapy and their combination with molecular-targeted therapies. The patient predictions demonstrate how this systems pharmacology model can be used to individualize immunotherapy treatments. When appropriately validated, these approaches may contribute to optimization of breast cancer treatment.

Abstract P1-16-08: Response to subsequent therapy after dual immune checkpoint blockade in metastatic breast cancer

Introduction: While initial studies have found that combining chemotherapy with immune checkpoint blockade (ICB) can augment responses, additional toxicity has been observed. The optimal sequencing of chemotherapy and ICB has not yet been described. Sequential responses to chemotherapy after ICB have been reported in various tumor types; however, data is limited, and this has not been described in breast cancer to date.

Methods: We identified patients (pts) from a small pilot study in HER2-negative metastatic breast cancer (MBC) who received at least 1 cycle of durvalumab (PD-L1 inhibitor) and tremelimumab (CTLA-4 inhibitor). We excluded pts without follow up data or if they did not receive subsequent systemic therapy. Comparison of differences between subgroups was calculated by Fisher's exact test for categorical variables and Wilcoxon rank-sum test for continuous variables. Time to treatment failure (TTF) of subsequent therapy and overall survival (OS) were assessed by the Kaplan-Meier method and differences between breast cancer subtype were compared by log-rank tests.

Results: Twenty-three pts received at least 1 cycle of ICB of whom 14 pts were eligible for this analysis. Nine had estrogen receptor positive (ER+) BC and 5 had triple negative (TN) BC. There were no statistically significant differences between the ER+ and TN subgroups in age, race, ethnicity, ECOG performance status (PS) at end of ICB, or sites of metastatic disease except for more lymph node metastases in the TN cohort (p=0.003). Overall response rates to ICB in this cohort was higher in TN vs ER+ (40% vs 0%, p=0.11). Pts received a median of 4 lines of systemic therapy for MBC prior to ICB. Subsequent therapy after ICB was eribulin in 29%, carboplatin/gemcitabine in 21%, palbociclib + endocrine therapy (ET) in 14%, anthracycline in 14%, ixabepilone +/- capecitabine in 14%, and paclitaxel in 7%. Clinical response was seen in 8 pts (57%), of whom 5 had ER+ BC and 3 had TNBC. The median TTF of subsequent therapy was 3.0 mo (1.9, 5.5), which compared to a median TTF for therapy prior to ICB of 2.5 mo. The median OS was 12.3 mo (2.3-13.3). There were no significant differences between the ER+ and TN cohorts (log-rank test p=0.74 and 0.90 for TTF and OS, respectively. Subsequent therapy was discontinued due to progressive disease in 44%, decline in PS in 19%, liver failure in 6%, treatment related adverse event in 6%, and unknown cause in 13%. Two pts remain on subsequent therapy with palbociclib + ET beyond 6 mo without disease progression. There were no statistically significant differences between TTF &gt;3 mo (n=5) and TTF &lt;3 mo (n=9) subgroups. Pts with TTF &gt;3 mo were numerically more likely to have a PS 0-1 (100 vs 78%), liver metastases (80 vs 56%), and ER+ BC (80 vs 56%). Pts with TTF &lt;3 mo had more lymphopenia (66% vs 20%) and more lines of prior systemic therapy for MBC (median 6 vs 4).

Conclusions: While median duration of response on subsequent therapy was short, a subset of pts had significant clinical responses. These findings provide rationale for prospective validation as they provide strategies for sequencing ICB with standard therapies.

Citation Format: Shah AN, Yalamanchili A, Helenowski I, Bhole S, Woodman J, Gradishar WJ, Cristofanilli M, Santa-Maria CA. Response to subsequent therapy after dual immune checkpoint blockade in metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-16-08.

Abstract P3-11-14: Circulating lymphocytes and pathologic complete response rate among patients with early stage triple negative breast cancer treated with neoadjuvant chemotherapy

Background: Chemotherapy can affect circulating immune cells. Low lymphocyte counts have been associated with worse prognosis in many cancers and inferior responses to immune checkpoint therapy. The effects of neoadjuvant chemotherapy on the immune system and its association with clinical outcomes in breast cancer is not well described.

Methods: A database was constructed of patients diagnosed with early stage triple negative breast cancer (TNBC) treated with neoadjuvant chemotherapy. Clinicopathologic information was extracted from the local electronic tumor registry or by chart review. Circulating lymphocyte and monocyte counts were assessed at the time of diagnosis, after neoadjuvant chemotherapy, and prior to surgery (all values in K/cu mm). These were correlated with clinicopathologic data, pathologic complete response (pCR) rates, and disease free survival (DFS) using rank sum test and Spearman correlation, t-test and log rank test, respectively.

Results: From 2000-2015, 426 patients with breast cancer treated with neoadjuvant chemotherapy were sequentially identified by an institutional electronic database. After excluding those who did not actually receive neoadjuvant therapy, were a subtype other than TNBC, and had missing receptor status or blood counts, 95 patients met eligibility for analysis. The median age of patients was 50 (range 26-79); 63 (66%) patients were treated with anthracyclines plus taxanes, 29 (31%) platinum-based chemotherapy, 2 (2%) with only anthracyclines, and 1 (1%) with only taxanes; 32 (34%) patients achieved a pCR; and 33 (35%) patients had recurrence events. Median follow up time was 47 months (range 13-123). No significant associations were found between pCR and changes in lymphocyte or monocyte count (mean lymphocyte reduction 0.74 in those with no-pCR versus 0.60 in those with pCR, p=0.30; mean monocyte reduction 0.0 in those with no-pCR versus 0.016 in those with pCR, p=0.78). There was no correlation between changes in lymphocytes or monocytes with DFS. Baseline lymphocytes or monocytes also did not correlate with pCR or DFS. Notably, there was a correlation between monocytes after neoadjuvant chemotherapy and pCR (mean monocyte level was 0.56 in those with no-pCR versus 0.46 in those with pCR, p=0.049) and DFS (median DFS in highest monocyte quartile 30 months versus in lowest quartile 107 months, p=0.022).

Conclusions: Our results suggest that transient lymphopenia from chemotherapy is not associated with clinical outcomes. However, we observed lower absolute circulating monocyte counts after neoadjuvant chemotherapy were associated with better clinical outcomes. Further research assessing the role of circulating immune cells is required to understand the effects of neoadjuvant chemotherapy on clinical outcomes, which may help inform immunotherapy-based strategies.

Citation Format: Talamantes SM, Costa RL, Rademaker A, Santa-Maria CA. Circulating lymphocytes and pathologic complete response rate among patients with early stage triple negative breast cancer treated with neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-11-14.

Abstract P6-17-16: Efficacy and safety of shorter duration of adjuvant trastuzumab for patients with HER2 positive early breast cancer: A meta-analysis of randomized controlled trials

Background: Trastuzumab has been shown to be able to improve disease free survival(DFS) and overall survival(OS) in HER2-positive breast cancer patients. Adjuvant trastuzumab is empirically recommended for 1 year as a standard regimen. However, several studies claimed that shorter duration of adjuvant trastuzumab is non-inferior to 12 months treatment with reduced cardiac toxicities and costs.

Methods: PubMed, EMBASE, Cochrane Library, Google scholar Web, ISI Web of Science, BIOSIS and CNKI, and major conference abstracts were searched systematically in June 2018 to identify eligible non-inferiority studies comparing the intervention outcomes of adjuvant trastuzumab in chemotherapy for women with HER-2 positive breast cancer between short-term and 1-year treatments. Hazard-Ratios(HR) and corresponding 95% Confidence Intervals(CI) were calculated to compare OS and DFS of trastuzumab between short-term and long-term treatments. Pooled data of Odds-Ratio was analyzed for cardiac toxicities.

Results: 5 articles were finally eligible in the study. Totally, there were 11,376 women with HER-2 positive early breast cancer, with 5,684 in short-term group and 5,692 in the 1-year group. We found a distinct difference of DFS (HR=1.19, 95% CI=1.08-1.30) and OS (HR=1.22, 95% CI=1.07-1.39) between short-term and 12 months trastuzumab in the total analysis, which demonstrated short-term treatment exhibited a worsening trend on DFS and OS. Subgroup analysis was performed based on estrogen receptor (ER) and lymph node status, and no statistical interaction could be found(p=0.12, 0.52, respectively). The two groups with different duration of trastuzumab treatment displayed statistically significant difference for cardiotoxicities, which favored shorter duration(OR=0.54, 95% CI=0.38-0.77).

Conclusions: 1-year adjuvant trastuzumab remains the standard strategy for HER2 positive early breast cancer, however, a concomitant higher risk of associated cardiac adverse effects should not be ignored.

Citation Format: Li J, Wang G, Wu Q, Chen C, Tu Y, Yao F, Wei W, Sun S, Santa-Maria CA, Geng P. Efficacy and safety of shorter duration of adjuvant trastuzumab for patients with HER2 positive early breast cancer: A meta-analysis of randomized controlled trials [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-16.

Abstract OT3-02-03: IMMUNe mOdulation in early stage estrogen receptor positive breast cancer treated with neoADjuvant Avelumab, Palbociclib, and Tamoxifen: The ImmunoADAPT study (NCT03573648)

Background:

While some patients with early stage endocrine receptor positive (ER+) breast cancer experience excellent prognosis, a subset of patients with more aggressive phenotypes still have a high rate of recurrence despite optimal adjuvant endocrine therapy and chemotherapy, thus novel therapies are needed for patients with high risk disease.

Although immune checkpoint blockade has shown significant benefit in numerous types of cancer, initial reports demonstrate low response rates to single agent programmed cell death ligand 1 (PD-L1) inhibition in ER+ breast cancer. Inhibitors of cyclin dependent kinases (CDK) 4 and 6 in combination with endocrine therapy are highly active in breast cancer, and recently have been demonstrated to recruit immune cells, and increase PD-L1 on tumor cells in preclinical models. Increased tumor infiltrating lymphocytes (TILs) has been observed with neoadjuvant treatment with CDK4/6 inhibitors in patients with ER+ breast cancer. We thus hypothesize that the addition of palbociclib (CDK4/6 inhibitor) will improve responses to avelumab (PD-L1) inhibitor in patients with high risk ER+ breast cancer.

Trial Design:

Eligible participants are those stage II or III ER+HER2- breast cancer (T2N0 must have ≥grade 2, T1N+ must have at least a 1.5cm breast primary). Patients will undergo a baseline MRI and biopsy, start tamoxifen +/- palbociclib for 1 cycle (1 cycle =28 days), and then undergo a repeat MRI and biopsy. Avelumab will be added to both arms in cycle 2. Patients will be treated for 3 cycles of avelumab with tamoxifen +/- palbociclib (thus 4 cycles total, including run-in without avelumab). Patients will be treated as long as there is no evidence of progression and therapy is tolerated, and then undergo MRI and surgery. The primary objective is to determine the clinical complete response (cCR) rate by MRI. Secondary objectives include evaluation of TILs (H&E), CD8 and FOXP3 by immunohistochemistry (IHC), T cell receptor (TCR) repertoire (TCR sequencing), multiplex gene expression panel (Nanostring), and multiplex IHC. Changes in these immune biomarkers will be assessed to determine differential immunophenotypic effects of palbociclib, and correlated to cCR in each arm.

The sample size of this pilot study is determined by primary analysis on the cCR rate. We hypothesize that the addition of palbociclib to tamoxifen will result in an increase rate of cCR in patients receiving avelumab. We hypothesize that the addition of avelumab will increase the response rate to palbociclib and tamoxifen by 30%. We thus estimate that a total of 40 evaluable patients (20 to each arm) will provide close to 80% power to detect a difference on cCR rates of 10% vs 40% at two-sided alpha level 10%. We will evaluate and compare cCR rates between arms by conducting Fisher's Exact test and reporting the estimated proportions together with their exact confidence intervals. Logistic regression analysis will also be conducted to explore the association between cCR and immune biomarkers.

This study has received IRB approval and is open as of Summer 2018.

Citation Format: Santa-Maria CA, Wang C, Cimino-Mathews A, Roussos-Torres E, Connolly RM, Wolff AC, Jaffee EM, Stearns V. IMMUNe mOdulation in early stage estrogen receptor positive breast cancer treated with neoADjuvant Avelumab, Palbociclib, and Tamoxifen: The ImmunoADAPT study (NCT03573648) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT3-02-03.

A phase II study evaluating the efficacy of zoledronic acid in prevention of aromatase inhibitor-associated musculoskeletal symptoms: the ZAP trial

PURPOSE

Aromatase inhibitor-associated musculoskeletal symptoms (AIMSS) are common adverse events of AIs often leading to drug discontinuation. We initiated a prospective clinical trial to evaluate whether bisphosphonates are associated with reduced incidence of AIMSS.

METHODS

In the single-arm trial, the Zoledronic Acid Prophylaxis (ZAP) trial, we compared the incidence of AIMSS against historical controls from the Exemestane and Letrozole Pharmacogenomics (ELPh) trial. Eligible women were postmenopausal with stage 0-III breast cancer planning to receive adjuvant AIs. AIMSS was assessed using the Health Assessment Questionnaire and Visual Analog Scale over 12 months in both trials. Participants in the ZAP trial received zoledronic acid prior to initiating letrozole and after 6 months; ELPh participants included in the analysis were taking letrozole but not bisphosphonates. We analyzed patient-reported outcomes (PROs) and bone density in the ZAP trial using mixed-effects linear regression models and paired t tests, respectively.

RESULTS

From 2011 to 2013, 59 postmenopausal women enrolled in ZAP trial. All 59 (100%) women received baseline and 52 (88%) received 6-month zoledronic acid, and had similar characteristics to historical controls from the ELPh trial (n = 206). Cumulatively during the first year of AI, 37 and 67% of ZAP and ELPh participants reported AIMSS (p < 0.001), respectively. Within the ZAP trial, we did not observe significant changes in other PROs; however, we report improvements in bone mineral density.

CONCLUSIONS

Compared to historical controls, zoledronic acid administered concomitantly with adjuvant AIs was associated with a reduced incidence of AIMSS. A randomized controlled trial is required to confirm these findings.

Abstract PD4-05: Patterns of genomic alterations in ER-positive advanced breast cancer patients treated with CDK4/6 inhibitors

Background:Cyclin D kinase inhibitors (CDK-is) have shown clinical efficacy in estrogen receptor (ER)-positive metastatic breast cancer (MBC) when combined with aromatase inhibition or estrogen receptor (ER) antagonism. Despite the benefit of this approach, clinical resistance develops sometimes early in the treatment without any response to endocrine therapy (primary endocrine resistance) or after initial response (secondary resistance) in all patients in the metastatic setting and the molecular basis for this resistance are still largely unknown. We evaluated the pattern of genomic alterations in circulating cell-free tumor DNA (ctDNA) analysis of metastatic breast cancer patients with ER-positive tumors treated with palbociclib combined with either letrozole or fulvestrant and progressing during therapy.

Methods: We conducted a retrospective study of patients with ER-positive MBC who had longitudinal assessment of their disease by ctDNA analysis. The plasma-based assay was performed utilizing Guardant360 (Guardant Health, CA), a digital NGS technology to sequence a panel of &gt; 50 cancer genes. After tabulating number of genomic alterations detected for every patient at baseline and after CDK-i therapy, analysis was performed to identify molecular profile changes in the entire population and in individuals with early progression of disease (&lt;6 months).

Results: We analyzed data of 15 ER-positive MBC patients: 8 patients received fulvestrant/palbociclib and 7 received letrozol/palpociclib. The most common mutations before CDK-i therapy were: PIK3CA (16%), TP53 (16%), ESR1 (13%), KIT (9%), EGFR (3%), APC (3%), ERBB2 (3%), MYC (3%), PTEN (3%), RB1 (3%). After therapy with CDK-i the pattern of mutations showed stable and persistent incidence of PIK3CA, TP53 and ESR1. However, new mutations where identified: FGFR1 (6%), IDH (2%), BRCA1 (2%), BRCA2 (2%), CCNE (2%), CCND1 (2%), RAF (2%), AR (2%), ALK(2%). Also, the pattern of gene amplifications presented an increased rate of MYC and FGFR1 amp. Patients with progression of disease before 6 months of CDK-i therapy presented baseline higher number and variation of mutations compared to patients with disease controlled beyond 6 months of therapy.

Conclusion: Longitudinal assessment with ctDNA analysis suggest that a genomic alteration landscape consisting of persistent detection of driver and acquired mutations along with emergent new abnormalities in regulatory genes could potentially be related to primary or secondary resistance to CDK-Is in ER+ MBC patients. Future investigation of these alterations should be conducted.

Citation Format: Cruz MR, Limentani K, Taxter T, Santa-Maria CA, Behdad A, Gradishar WJ, Nagy RJ, Cristofanilli M. Patterns of genomic alterations in ER-positive advanced breast cancer patients treated with CDK4/6 inhibitors [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD4-05.

Abstract OT1-05-01: A phase I/II, single arm, non-randomized study of ribociclib (LEE011), a CDK 4/6 inhibitor, in combination with bicalutamide, an androgen receptor (AR) inhibitor, in advanced AR+ triple-negative breast cancer

Background: Triple negative breast cancer (TNBC) is a heterogeneous disease encompassing distinct intrinsic molecular subtypes, including a luminal androgen receptor (AR) subtype, characteristically dependent on AR signaling. The AR is expressed in more than 50% of TNBCs. Bicalutamide is an oral, non-steroidal, AR antagonist, which has been studied in metastatic TNBC with a clinical benefit rate of 19% at 24 weeks. In preclinical models, cyclin dependant kinase (CDK) 4/6 inhibition has been shown to restore sensitivity to AR inhibition, and may thus be an important resistance mechanism. Ribociclib is an orally bioavailable, highly specific CDK4/6 inhibitor that induces cell cycle arrest, already approved in endocrine receptor positive breast cancers. We hypothesize that inhibition of CDK inhibition can enhance the activity of anti-androgen therapy in TNBC that express AR.

Methods: We designed a phase I/II, single arm, non-randomized, open label study of the combination of bicalutamide with ribociclib in women with advanced AR-positive TNBC. The primary objective of the phase I component is to determine the maximum tolerated dose of the combination, and of the phase II component to assess the clinical benefit rate at 16 weeks. Secondary objectives include progression free and overall survival, objective response rates, and safety and tolerability. Exploratory objectives will be to assess AR quantification, localization and splice variants in circulating tumor cells, as well as quantification of pan and phospho proteins of Rb. Eligible patients must have measurable metastatic or unresectable AR-positive TNBC and have had no more than 1 line of systemic therapy for metastatic disease. The phase I study will be conducted using a 3+3 dose escalation schema, 12 to 18 patients are expected to enroll. The phase II component will utilize a Simon's two stage design, enrolling 24 patients for the first stage. At least 5 subjects must have clinical benefit by 16 weeks to proceed onto the second stage, which would enroll an additional 22 subjects for a total of 46 patients. The study will be powered to detect a clinical benefit rate of 40% with a power of 80% and a type I error rate of 10%. Contact dmusapatika@hoosiercancer.org for more information about the study.

Citation Format: Santa-Maria CA, Rampurwala M, Wisinski K, Toppmeyer D, O'Regan R. A phase I/II, single arm, non-randomized study of ribociclib (LEE011), a CDK 4/6 inhibitor, in combination with bicalutamide, an androgen receptor (AR) inhibitor, in advanced AR+ triple-negative breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-05-01.

Genomic landscape of DNA repair genes in cancer

DNA repair genes are frequently mutated in cancer, yet limited data exist regarding the overall genomic landscape and functional implications of these alterations in their entirety. We created comprehensive lists of DNA repair genes and indirect caretakers. Mutation, copy number variation (CNV), and expression frequencies of these genes were analyzed in COSMIC. Mutation co-occurrence, clinical outcomes, and mutation burden were analyzed in TCGA. We report the 20 genes most frequently with mutations (n > 19,689 tumor samples for each gene), CNVs (n > 1,556), or up- or down-regulated (n = 7,998). Mutual exclusivity was observed as no genes displayed both high CNV gain and loss or high up- and down-regulation, and CNV gain and loss positively correlated with up- and down-regulation, respectively. Co-occurrence of mutations differed between cancers, and mutations in many DNA repair genes were associated with higher total mutation burden. Mutation and CNV frequencies offer insights into which genes may play tumor suppressive or oncogenic roles, such as NEIL2 and RRM2B, respectively. Mutual exclusivities within CNV and expression frequencies, and correlations between CNV and expression, support the functionality of these genomic alterations. This study provides comprehensive lists of candidate genes as potential biomarkers for genomic instability, novel therapeutic targets, or predictors of immunotherapy efficacy.

Developmental therapeutics for inflammatory breast cancer: Biology and translational directions

Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer, which accounts for approximately 3% of cases of breast malignancies. Diagnosis relies largely on its clinical presentation, and despite a characteristic phenotype, underlying molecular mechanisms are poorly understood. Unique clinical presentation indicates that IBC is a distinct clinical and biological entity when compared to non-IBC. Biological understanding of non-IBC has been extrapolated into IBC and targeted therapies for HER2 positive (HER2+) and hormonal receptor positive non-IBC led to improved patient outcomes in the recent years. This manuscript reviews recent discoveries related to the underlying biology of IBC, clinical progress to date and suggests rational approaches for investigational therapies.