High-risk Early Breast Cancer Research Articles

Two Instrument Comparison of Reagents From a US FDA-Approved Assay for the Assessment of Ki-67 in High-Risk Early Breast Cancer.

The objective of this study was to measure concordance of results obtained from the US Food and Drug Administration–approved Ki-67 immunohistochemistry MIB-1 pharmDx assay performed on the Dako Omnis automated staining instrument (Omnis) versus results produced from the assay reagents applied using an optimized protocol on the more widely available Autostainer Link 48 (ASL48) platform. Tissue sections obtained from 40 formalin-fixed paraffin-embedded breast carcinoma samples, with available Oncotype DX Breast Recurrence Score (RS) results, were stained. Three certified pathologists scored slides at 3 timepoints, totaling 360 observations for each instrument (N=720 total) using the approved scoring approach. Using the ≥20% cutoff, agreement was calculated with corresponding 2-sided 95% percentile bootstrap confidence intervals (CIs). Pairwise comparisons (N=360) from the interinstrument evaluation, performed with all observers, resulted in 325 (90.3%) concordant outcomes (244 negative and 81 positive) and 35 (9.7%) discordant outcomes. The overall agreement was 90.3% (95% confidence interval, 85.6% to 94.4%). No significant systematic differences were observed between instruments. Specimens scored from the Omnis were on average <1% higher than ASL48, with high correlation and little bias between the continuous Ki-67 scores (concordance correlation coefficient=0.916). Most specimens with a Ki-67 score ≥20% had a RS >25. This study demonstrated that good concordance can be achieved with the reagents run on the ASL48 instrument when using an optimized protocol and standardized scoring.

New Adjuvant Treatment for High-Risk Early Breast Cancer.

Olaparib (Lynparza) is now approved for the adjuvant treatment of adult patients who have, or are suspected to have, the germline variation of BRCA-mutated human epidermal growth factor receptor 2-negative high-risk early breast cancer and who were previously treated with neoadjuvant or adjuvant chemotherapy.

EE183 Cost-Effectiveness Analysis of Early Versus Delayed Use of Abemaciclib Combination Treatment in Patients with HR+/HER2- High-Risk Early Breast Cancer: A US Payer Perspective

Clinical guidelines recommend use of abemaciclib, a cyclin-dependent kinase 4 and 6 inhibitor, in combination with endocrine therapy (ET) as adjuvant treatment for patients with hormone receptor-positive (HR+), HER2-negative (HER2-) early breast cancer (EBC) at high risk of recurrence or in combination with fulvestrant if patients develop metastatic breast cancer (MBC). We evaluated the cost-effectiveness of early use of abemaciclib and ET combination as first-line adjuvant therapy and then use of fulvestrant after developing MBC (early use) versus ET treatment in EBC followed by delayed use of combination abemaciclib and fulvestrant in MBC (delayed use).

Adjuvant abemaciclib for high-risk early breast cancer (EBC): Factors increasing the rate of treatment discontinuations in monarchE.

527 Background: Adjuvant abemaciclib plus endocrine therapy (ET) demonstrated clinically meaningful improvement in reducing the risk of recurrence in patients (pts) with HR+, HER2– high risk EBC. In monarchE, 25.6% pts discontinued abemaciclib before completing the 2-year treatment period due to reasons other than recurrence. This exploratory analysis evaluates the impact of baseline factors on time to discontinuation for abemaciclib-treated patients with an aim to identify pts at higher risk of discontinuation. Methods: Time to discontinuation(TTD) was defined as time from first dose to the discontinuation of abemaciclib or all treatment due to reasons other than recurrence. These exploratory analyses evaluated the association between TTD and baseline demographics, disease characteristics, and the extent of pre-existing medical comorbidities. Factors with p-value &lt;0.05 in the univariate Cox model were considered as potentially associated with TTD and then fitted into a multivariate Cox model with stepwise variable selection, with entry and retaining p-value threshold of 0.05. Discontinuation rates at selected timepoints (6-month, 12-month, 18-month, 24-month) within each subgroup were estimated using the Kaplan-Meier method. Results: The following variables were significantly associated with higher risk of discontinuation in the multivariate model: Age ≥65 yr, enrolled in North America or EU, ECOG PS=1, post-menopausal, 1-3 positive nodes, or 4 or more pre-existing comorbidities. The majority of discontinuations occurred within the first 6 months of the treatment period; thus, this timepoint was selected to estimate discontinuation rates for factors independently associated with TTD (Table). Complete results on discontinuation rates at other timepoints will be reported in the presentation. Conclusions: This exploratory analysis identified several factors associated with a greater risk of discontinuation. These results illustrate the importance of close monitoring and dose adjustments early on, particularly for patients with an increased risk of discontinuation prior to completing the 2-yr treatment period of abemaciclib. Clinical trial information: NCT03155997. [Table: see text]

The ImPrint immune signature to identify patients with high-risk early breast cancer who may benefit from PD1 checkpoint inhibition in I-SPY2.

514 Background: The remarkable increase of novel Immuno-Oncology drugs in many malignancies has led to the need for biomarkers to identify who would benefit. Various predictive biomarkers have been developed (PD-1/PD-L1 expression, mutations in mismatch repair genes and microsatellite instability, tumor mutational burden and immune infiltration), none have consistently predicted efficacy. The I-SPY2 consortium qualified several expression-based immune biology related signatures that predict response to PD1 checkpoint inhibition. Here we assessed whole transcriptome data of high-risk early-breast cancer (EBC) patients who received Pembrolizumab within the neoadjuvant biomarker-rich I-SPY2 trial (NCT01042379), aiming to migrate the I-SPY2 research findings to a robust clinical grade platform signature to predict sensitivity to PD1 checkpoint inhibition. Methods: Whole transcriptome microarray data were available from pre-treatment biopsies of 69 HER2- patients enrolled in the Pembrolizumab (4 cycles) arm of the I-SPY2 trial. All patients had a High-Risk 70-gene MammaPrint profile. Pathologic complete response (pCR) was defined as no residual invasive cancer in breast or nodes at the time of surgery. Of the 69 patients, 31 had a pCR (12 HR (hormonal receptor)+HER2-, 19 Triple Negative (TN)), while 38 (28 HR+HER2-, 10 TN) had residual disease (RD). To identify the most predictive genes associated with pCR, gene selection was performed comparing pCR and RD groups by iteratively splitting the dataset in training and test, balancing for HR status. Due to limited sample size, leave one out cross validation was used for performance assessment. Genes with effect size &gt; 0.45 were considered significant. Results: A signature of 53 genes, named ImPrint, was identified with overall sensitivity and specificity &gt; 90% and &gt; 80% for predicting pCR to pembrolizumab in all patients. Sensitivity and specificity in TN were &gt; 95% and ≥70%, and in HR+HER2- &gt; 80% and &gt; 85%, respectively. The Positive Predictive Value (PPV) is 77% for the HR+HER2- subgroup. Biological annotation of the 53 genes showed that over 90% of the genes have known immune system related functions, of which 63% were previously known to be involved in immune response (including genes coding PD-L1 and PD-1, as well as those identified in I-SPY2). Conclusions: In the signature development phase, ImPrint predicts pCR to Pembrolizumab in a set of 69 high risk EBC with high sensitivity and specificity. The signature features genes with immune-related functions known to be involved in immune response indicating that it might aid identifying patients with an immune-active phenotype. Importantly, ImPrint appears effective in identifying a subset of HR+HER2- patients who could benefit from immunotherapy. External validation in independent dataset(s) is ongoing and will be presented at the time of the meeting.

Predictive value of ectopic HORMAD1 tumor expression for high-dose platinum-based chemotherapy benefit in patients with high-risk HER2-negative breast cancer.

541 Background: The meiotic DNA break regulator HORMAD1 is aberrantly expressed in many cancers and is associated with increased genomic instability. The susceptibility of HORMAD1 expressing tumors to agents targeting DNA damage repair (DDR) pathways is poorly understood since clinical data within the context of a randomized clinical trial (RCT) is lacking. Here, we retrospectively studied HORMAD1 expression as a putative predictive biomarker in an RCT for benefit of adjuvant high-dose platinum-based chemotherapy (HDCT) with autologous stem cell support in patients with high-risk HER2-negative early breast cancer (BC). Methods: Patients with stage III BC participated in an RCT comparing HDCT to conventional chemotherapy (CDCT; Rodenhuis et all, NEJM, 2003; Steenbruggen et all, JAMA Oncol, 2020). We studied the subgroup with HER2-negative BC for whom tumor BRCA1-like classification was previously determined using a validated DNA comparative genomic hybridization algorithm (Vollebergh et all, BCR, 2014). Tumor HORMAD1 expression was determined on FFPE samples using RNAscope, an RNA in situ hybridization method, and classified as negative (no expression) or positive (any expression detected). Results: For 195/246 (79.3%) HER2-negative patients treated according to protocol, HORMAD1 RNAscope status was available; dropout was due to absence or insufficient quality of tumor specimens. HORMAD1 positivity was enriched in triple-negative breast cancer (TNBC) (23/47; 48.9%). Furthermore, in all HER2-negative BCs, HORMAD1 positivity (45/195; 23.1%) was associated with age ≤40 years, histological grade III, &lt;10 positive lymph nodes, breast-conserving surgery, BRCA1-like profile, and tumor-infiltrating lymphocytes (TILs) &gt;10%. Such association, although not significant, was also observed within TNBC. During a median follow-up of 20.3 years, 124 (63.6%) recurrences and 115 deaths (59.0%) occurred. The prognostic effect of HORMAD1 positivity on overall survival (OS) varied with follow-up time and was borderline significant at 10 years and significant thereafter (10-year: adjusted (adj.) HR 0.47, 95% CI 0.21-1.04; 15-year: adj. HR 0.25, 95% CI 0.07-0.91). Benefit on RFS from HDCT over CDCT was stronger in patients with HORMAD1-positive tumors (adj. HR 0.18, 95% CI 0.06-0.54) than in patients with HORMAD1-negative tumors (adj. HR 0.69, 95% CI 0.46-1.02) (P-interaction = 0.02). Similar results were observed for OS. Conclusions: In this retrospective sub study of 195 patients with high-risk HER2-negative BC participating in an RCT, tumor HORMAD1 expression is predictive for benefit of high-dose platinum-based chemotherapy. Our observations are consistent with the prior observations that HORMAD1 expression is associated with genomic instability and impaired DDR pathways. Further research is warranted to validate our findings. Clinical trial information: NCT03087409.

63P Efficacy and safety results by menopausal status in monarchE: Adjuvant abemaciclib combined with endocrine therapy in patients with HR+, HER2- high-risk early breast cancer

Abemaciclib is the first and only approved CDK4 & 6 inhibitor in the adjuvant setting for certain types of HR+, HER2-, node-positive, high-risk early breast cancer (EBC). Patient (Pts) with HR+, HER2- tumors who are premenopausal (preM) may have a different tumor biology and response to endocrine therapy (ET) than postmenopausal (postM) pts, warranting analysis of the prespecified subgroup within monarchE.

59MO Adjuvant abemaciclib combined with endocrine therapy (ET): Efficacy results in monarchE cohort 1

Abemaciclib (oral CDK4 & 6 inhibitor) plus ET as adjuvant treatment for HR+, HER2- high risk early breast cancer (EBC), previously demonstrated robust benefit with an acceptable safety profile in the monarchE trial. Here we present efficacy data in a monarchE patient population (Cohort 1) which has a high risk of recurrence, can easily be identified in clinical practice, and recently received regulatory approval.

62P Outcomes of high-risk breast cancer (BC) patients from El Álamo IV registry and GEICAM adjuvant clinical trials

Chemotherapy (CT) followed by endocrine therapy (ET) is the current standard of care for high-risk hormone receptor (HR)-positive/HER2-negative early breast cancer (EBC). The monarchE, with 27-months follow-up, showed that the addition of abemaciclib for 2 years in combination with ET improves the 3-years invasive relapse rate (IRR) and distant relapse rate (DRR) for patients (pts) with high-risk EBC. Obtaining data on the long-term risk of relapse is needed to put into context the magnitude of abemaciclib benefit.

Adjuvant Abemaciclib Plus Endocrine Therapy in the Treatment of High-Risk Early Breast Cancer: ASCO Guideline Rapid Recommendation Update Q and A.

Adjuvant Abemaciclib Plus Endocrine Therapy in the Treatment of High-Risk Early Breast Cancer: ASCO Guideline Rapid Recommendation Update Q and A.

MUC1 (CA27.29) before and after Chemotherapy and Prognosis in High-Risk Early Breast Cancer Patients.

Simple SummaryCA27.29 (MUC1) is a well described biomarker for prediction of prognosis and treatment efficacy. CA27.29 is mainly evaluated in the preoperative setting. However, testing of postoperative levels and additional assessment after chemotherapy might be more informative for analyzing the usefulness of CA27.29 in relation to the efficacy of chemotherapy. Thus, both pre- and post-chemotherapy values were assessed from patients enrolled in the breast cancer SUCCESS-A trial. Pre-chemotherapy assessment was associated with disease-free survival. It had no prognostic value in node-negative patients, but there was a clear association in node-positive patients. Furthermore, it was shown that post-chemotherapy CA27.29 assessment did not add any prognostic value, either on its own or in addition to pre-chemotherapy assessment. In conclusion, this indicates that pre- and post-chemotherapy values do not provide additional information. However, pre-chemotherapy CA27.29 could be a suitable tool to identify a group with unfavorable prognosis among node-positive patients.Soluble MUC1 has been discussed as a biomarker for predicting prognosis, treatment efficacy, and monitoring disease activity in breast cancer (BC) patients. Most studies in adjuvant settings have used preoperative assessment. This study, part of the SUCCESS-A trial (NCT02181101), assessed the prognostic value of soluble MUC1 before and after standard adjuvant chemotherapy. Patients with high-risk BC were treated within the SUCCESS-A trial with either three cycles of 5-fluorouracil, epirubicin, and cyclophosphamide followed by three cycles of docetaxel or three cycles of FEC followed by three cycles of docetaxel and gemcitabine. Cox regression analyses were performed to investigate the prognostic value of CA27.29 before and after chemotherapy relative to disease-free survival (DFS), along with established BC prognostic factors such as age, body mass index, tumor size, nodal status, estrogen receptor, progesterone receptor, HER2 status, and grading. Pre-chemotherapy and post-chemotherapy CA27.29 assessments were available for 2687 patients of 3754 randomized patients. Pre-chemotherapy CA27.29 assessment was associated with DFS in addition to established prognostic factors. It had no prognostic value in node-negative patients, but there was a clear association in node-positive patients. Post-chemotherapy CA27.29 assessment did not add any prognostic value, either on its own or in addition to pre-chemotherapy CA27.29 assessment.

Adjuvant abemaciclib combined with endocrine therapy for high-risk early breast cancer: safety and patient-reported outcomes from the monarchE study

In monarchE, abemaciclib plus endocrine therapy (ET) as adjuvant treatment of hormone receptor-positive, human epidermal growth factor 2-negative, high-risk, early breast cancer (EBC) demonstrated a clinically meaningful improvement in invasive disease-free survival versus ET alone. Detailed safety analyses conducted at a median follow-up of 27 months and key patient-reported outcomes (PROs) are presented. The safety population included all patients who received at least one dose of study treatment (n= 5591). Safety analyses included incidence, management, and outcomes of common and clinically relevant adverse events (AEs). Patient-reported health-related quality of life, ET symptoms, fatigue, and side-effect burden were assessed. The addition of abemaciclib to ET resulted in higher incidence of grade ≥3 AEs (49.7% versus 16.3% with ET alone), predominantly laboratory cytopenias [e.g. neutropenia (19.6%)] without clinical complications. Abemaciclib-treated patients experienced more serious AEs (15.2% versus 8.8%). Discontinuation of abemaciclib and/or ET due to AEs occurred in 18.5% of patients, mainly due to grade 1/2 AEs (66.8%). AEs were managed with comedications (e.g. antidiarrheals), abemaciclib dose holds (61.7%), and/or dose reductions (43.4%). Diarrhea was generally low grade (grade 1/2: 76%); grade 2/3 events were highest in the first month (20.5%), most were short-lived (≤7 days) and did not recur. Venous thromboembolic events (VTEs) were higher with abemaciclib+ ET (2.5%) versus ET (0.6%); in the abemaciclib arm, increased VTE risk was observed with tamoxifen versus aromatase inhibitors (4.3% versus 1.8%). PROs were similar between arms, including being 'bothered by side-effects of treatment', except for diarrhea. At ≥3 months, most patients reporting diarrhea reported 'a little bit' or 'somewhat'. In patients with high-risk EBC, adjuvant abemaciclib+ ET has an acceptable safety profile and tolerability is supported by PRO findings. Most AEs were reversible and manageable with comedications and/or dose modifications, consistent with the known abemaciclib toxicity profile.

Cyclin dependent kinase 4/6 inhibitors in early breast cancer: what is the role of Ki-67?

Hormone receptor-positive and HER2-negative early breast cancer accounts for approximately 70% of all breast cancer diagnoses. In this setting, adjuvant endocrine therapy significantly improves survival outcomes, with selective use of neoadjuvant or adjuvant chemotherapy, as guided by clinical, pathological, and molecular recurrence risk assessments. To our knowledge, the monarchE study is the first randomised, clinical, phase 3 trial to show benefit, in terms of invasive disease-free survival, from the addition of the cyclin dependent kinase 4/6 (CDK4/6) inhibitor abemaciclib to adjuvant endocrine therapy in patients with high-risk hormone receptor-positive, HER2-negative, and lymph node-positive early breast cancer. 1 Johnston SRD Harbeck N Hegg R et al. Abemaciclib combined with endocrine therapy for the adjuvant treatment of HR+, HER2-, node-positive, high-risk, early breast cancer (monarchE). J Clin Oncol. 2020; 38: 3987-3998 Google Scholar , 2 Harbeck N Rastogi P Martin M et al. Adjuvant abemaciclib combined with endocrine therapy for high-risk early breast cancer: updated efficacy and Ki-67 analysis from the monarchE study. Ann Oncol. 2021; 32: 1571-1581 Google Scholar These results led to the subsequent approval of abemaciclib by the US Food and Drug Administration (FDA) in October, 2021, restricted to patients who have tumours with immunohistochemical Ki-67 expression of 20% or higher, as measured by the companion diagnostic MIB-1 pharmDx assay (Dako Omnis, Agilent Technologies, Santa Clara, CA, USA).

Abstract GS3-06: Primary results of the cTRAK TN trial: A clinical trial utilising ctDNA mutation tracking to detect minimal residual disease and trigger intervention in patients with moderate and high risk early stage triple negative breast cancer

Abstract Background Detection of circulating tumour DNA (ctDNA) in patients (pts) who have completed treatment for early-stage triple negative breast cancer (TNBC) is associated with a very high risk of future relapse. Identifiying those at high risk of subsequent relapse may allow tailoring of further therapy to delay or prevent recurrence. The c-TRAK TN trial assessed the utility of prospective ctDNA surveillance in pts treated for TNBC and the activity of pembrolizumab (P) in pts with ctDNA detected.. Methods c-TRAK TN, a multi-centre phase II trial with integrated prospective screening component, enrolled pts with early-stage TNBC and either residual disease following neoadjuvant chemotherapy, or tumour size &amp;gt;20mm and/or axillary lymph node involvement if adjuvant chemotherapy was given. Tumour tissue was sequenced to identify somatic mutations suitable for tracking using personalised digital PCR ctDNA assays (BioRad QX200). Pts had “active” ctDNA surveillance via blood sample testing every 3 months to 12 months (potential up to 18 months if samples missed due to COVID) during which time if ctDNA was detected (ctDNA+) pts could be randomised 2:1 to P (200mg i.v. q 3 weeks for 1 year) or observation (Obs). Pts and clinicians were blinded to ctDNA+ results unless they were allocated P, when staging scans were done and those free of clinical recurrence started treatment. Following advice from the Independent Data Monitoring Committee, the Obs arm closed on 16/06/2020 with all subsequent ctDNA+ pts allocated P. Following the completion of active ctDNA surveillance, 3-monthly visits continued to 24 months to be analysed retrospectively. The aim was to recruit 150 pts to ctDNA surveillance, assuming 30% would be ctDNA+ within 12 months, allowing ctDNA+ rate to be estimated with a 2-sided 95%CI of +/- 7.3%. Co-primary endpoints are i) rates of ctDNA detection by 12 and 24 months from start of ctDNA surveillance; ii) rates of sustained ctDNA clearance on P defined as absence of detectable ctDNA, or disease recurrence 6 months after starting P.. Results 208 pts were registered between 30/01/18 and 06/12/19, 185 had tumour sequenced, 171 (92.4%) had trackable mutations, and 161 entered ctDNA surveillance. The rate of ctDNA detection by 12 months after start of surveillance was 27.3% (44/161, 95% CI 20.6-34.9). ctDNA+ rates from baseline, 3, 6, 9 and 12 month ctDNA samples were 23/161 (14.3%), 6/115 (5.2%), 6/99 (5.1%), 7/84 (8.3%), and 2/84 (2.4%) respectively. An additional 2 pts were ctDNA+ on COVID extended active surveillance at 15 (1/51, 2%) or 18 months (1/11, 9%). 7 pts relapsed without prior ctDNA detection. 45 pts entered the therapeutic component of the trial (initially 31 to P and 14 to Obs). 1 Obs pt was re-allocated to P. Of pts allocated to P, 72% (23/32) had metastatic disease at time of ctDNA detection on staging scans (75% (12/16) who were ctDNA+ at baseline and 69% (11/16) at other timepoints). 4 pts declined to start P, largely due to COVID concerns. Of the 5 pts who commenced P, at the time of analysis none achieved sustained ctDNA clearance and 4 had recurred. In pts allocated to Obs, median time to recurrence was 4.1 months (95% CI: 3.2-not-defined).. Conclusion The c-TRAK TN trial is to our knowledge the first study to assess the proof-of-principle of whether ctDNA assays have clinical utility in guiding further therapy in TNBC. Relatively few pts commenced P treatment precluding assessment of potential activity. At enrollment, patients had a relatively high of rate of undiagnosed metastatic disease when imaged. Our findings have implications for future trial design, emphasizing the importance of early start of ctDNA testing, and more sensitive and/or more frequent ctDNA testing regimes. Citation Format: Nicholas Turner, Claire Swift, Ben Jenkins, Lucy Kilburn, Maria Coakley, Matthew Beaney, Lisa Fox, Katie Goddard, Isaac Garcia-Murillas, Peter Hall, Catherine Harper-Wynne, Tamas Hickish, Sarah Kernaghan, Iain Macpherson, Alicia Okines, Carlo Palmieri, Sophie Perry, Katrina Randle, Claire Snowdon, Hilary Stobart, Andrew Wardley, Duncan Wheatley, Simon Waters, Matthew Winter, Judith Bliss. Primary results of the cTRAK TN trial: A clinical trial utilising ctDNA mutation tracking to detect minimal residual disease and trigger intervention in patients with moderate and high risk early stage triple negative 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 GS3-06.

Abstract PD10-07: Chemokine12 (CK12) tertiary lymphoid gene expression signature as a predictor of response in 3 immunotherapy arms of the neoadjuvant ISPY 2 TRIAL - pembrolizumab with and without SD101, and durvalumab combined with olaparib - and in 9 other arms of the trial including platinum-based and dual-anti-HER2 therapies

Abstract Background: The CK12 expression signature consists of genes CCL2, CCL3, CCL4, CCL5, CCL8, CCL18, CCL19, CCL21, CXCL9, CXCL10, CXCL11, CXCL13 and was previously shown to associate with the presence of T and B cell rich tertiary lymphoid structures in melanoma and other cancers, and with better patient survival independent of tumor staging and treatment. I-SPY 2 is a biomarker-rich, phase II neoadjuvant platform trial for high risk early stage breast cancer. Here we leverage the I-SPY 2 biomarker program to test the hypothesis that this signature associates with sensitivity to neoadjuvant immunotherapies and potentially other classes cancer therapeutics in breast cancer. Methods: Data from 1130 patients across 12 arms of I-SPY2 (control (ctr): 210; veliparib/carboplatin (VC): 71; neratinib (N): 114; MK2206: 93; ganitumab: 106; ganetespib: 93; AMG386: 134; TDM1/pertuzumab(P): 52; H/P: 44; pembrolizumab (pembro): 69; durvalumab/olaparib (durva/olap): 71; pembro/SD101: 72) were available for analysis. Pre-treatment FF (n=987) or FFPE (n=143) biopsies were assayed using Agilent gene expression arrays. Signature scores were calculated as the average expression level across the 12 genes, after z-score normalization. We used logistic modeling to assess association with pCR in each arm in a model adjusting for HR and HER2 (likelihood ratio test, p&amp;lt;0.05). This analysis was also performed within HR/HER2 receptor subsets, numbers permitting. We also assessed differences in levels across HR/HER2 subsets using ANOVA and Tukey post-hoc testing. Our statistics are descriptive rather than inferential and do not adjust for multiplicities of other biomarkers outside this study. Results: CK12 levels associate with HR/HER2 status (ANOVA p=1.07E-14), with higher levels in TN and HR-HER2+ subsets and lower levels in HR+ groups. Overall, patients with higher levels of CK12 were significantly more likely to achieve pCR in all 3 IO arms: pembro (OR=3.4/1SD), pembro/SD101 (OR=4/1SD), and durva/olaparib (OR=2.5/1SD) (LR p&amp;lt;0.05), in a model adjusting for HR status. The CK12 performed favorably in predicting response to pembro/SD101 compared to several other genomic signatures measuring intratumoral immune response. Higher CK12 also associates with response to the ANG1/2 inhibitor AMG386, an agent known to have immune modulatory activity. Higher CK12 was moderately associated with pCR in the control (OR=2.0/1SD), neratinib (OR=1.7/1SD), veliparib/carboplatin (OR=2.0/1SD), ganitumab (OR= 1.7/1SD) and TDM1/P arms (OR=2.1/1SD). Within the HR+HER2- subset, CK12 associated with pCR in all three IO arms, and in the control, AMG386, ganitumab, and ganetespib arms. Within the smaller TN subset, it associated with response in pembro and pembro/SD101 arms but not in durva/olaparib, and in the neratinib and AMG386 arms. Chemokine12 mostly did not associate with pCR in HER2+ subsets, except for HR+HER2+ patients treated with neratinib, and HR-HER2+ patients in the original control arm (trastuzumab). Conclusion: The CK12 signature is highly predictive of complete pathologic response to immuno-oncology agents and other therapeutics supporting the role of the crosstalk within the tumor immune microenvironment in predicting response across subtypes. This gene expression signature can be readily obtained from microarrays and warrants further investigation in future arms of ISPY2 as a predictive biomarker. Citation Format: Hatem Soliman, Denise Wolf, Jo Chien, Christina Yau, Michael Campbell, Mark Magbanua, Ruixiao Lu, Nicholas O'Grady, Lamorna Brown-Swigart, Gillian Hirst, Beverly Parker, Laura Sit, Smita Asare, Doug Yee, Angie DeMichele, Rita Nanda, Lajos Pusztai, Don Berry, Laura Esserman, Laura Van't Veer. Chemokine12 (CK12) tertiary lymphoid gene expression signature as a predictor of response in 3 immunotherapy arms of the neoadjuvant ISPY 2 TRIAL - pembrolizumab with and without SD101, and durvalumab combined with olaparib - and in 9 other arms of the trial including platinum-based and dual-anti-HER2 therapies [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 PD10-07.

Abstract P2-14-07: Marrow-infiltrating lymphocytes as adoptive immunotherapy for breast cancer

Abstract Background: The bone marrow harbors tumor-antigen specific T cells in patients with breast cancer (1). Marrow-infiltrating lymphocytes (MILs®) are the product of activating and expanding bone-marrow T cells (2). In multiple myeloma, transfer of MILs as adoptive cell therapy has demonstrated anti-tumor activity (3). The use of adoptive transfer of autologous tumor-infiltrating lymphocytes (TILs) has been used successfully for hormone-receptor positive (HR+) metastatic breast cancer (4). Expansion of MILs was previously shown to be feasible in breast cancer, non-small cell lung cancer (NSCLC), prostate, head and neck, glioblastoma and multiple myeloma (5). Using an expanded cohort, we demonstrate that tumor-specific MILs can be expanded from bone marrow in patients with breast cancer. Methods: Bone marrow aspiration and blood samples were collected from 8 patients with metastatic and high-risk early-stage breast cancer, including 3 patients with HR+/HER2-, 2 patients with HER2+, and 3 patients with triple negative subtypes, at Providence Cancer Institute (Portland, OR). MILs and peripheral blood lymphocytes were activated and expanded from patient samples during a 10-day proprietary process. T cell lineage-specific markers CD3, CD4 and CD8 were characterized by flow cytometry pre- and post- expansion. Tumor-specific T cells were quantitated in expanded MILs and peripheral blood lymphocytes using a previously described cytokine-secretion assay (3). Briefly, they were defined as the IFNy-producing population by flow cytometry. Autologous antigen-presenting cells (APCs) were pulsed with lysates from allogeneic cancer cell lines and co-cultured with activated MILs or peripheral blood lymphocytes. APCs pulsed with irrelevant mis-matched cancer cell line lysates or media alone were used as negative controls. Results: In all harvested samples, MILs expansion successfully resulted in a selective increase in CD3+ T cells. Cytokine-producing CD4+ and CD8+ T cells were detected in all expanded MILs samples, but not in any of the matched activated and expanded peripheral blood lymphocytes. MILs were successfully expanded in HR+/HER2-, HER2+, and triple negative subtypes without apparent differences in activity as measured by cytokine production. Conclusion: MILs isolated from this expanded cohort of metastatic and high-risk early stage breast cancer patients demonstrated cytokine production in response to pulsed cancer cell line lysates, consistent with our experience with other solid (5) and hematological (3) malignancies. A phase II trial to evaluate MILs in combination with a checkpoint inhibitor is underway in patients with anti-PD1/PDL1-refractory NSCLC (NCT04069936). These preclinical data demonstrate that expanding MILs is feasible and could be evaluated therapeutically in breast cancer.

Abstract PD9-08: Prognostic value of EndoPredict test in patients screened for UNIRAD, a UCBG randomized, double blind, phase III international trial evaluating the addition of everolimus (EVE) to adjuvant hormone therapy (HT) in women with high risk HR+, HER2- early breast cancer (eBC)

Abstract Background: The double blind randomized UNIRAD trial (NCT01805271) showed no evidence that adding Everolimus (EVE) to adjuvant endocrine therapy (EHT) for high-risk early breast cancer (BC) improved 3-year disease-free survival (iDFS) compared with EHT alone. In this trial, high risk was defined by any T and either ≥4N+, or ≥1N+ after neoadjuvant treatment, or ≥1N+ and EPclin high risk (EPCH) score ≥3.3. This sub analysis is aimed to verify prognostic added value of EndoPredict test results on outcomes in patients screened for the UNIRAD study.. Material and methods: From May 2015 to March 2020, 777 patients were screened with the EndoPredict test. Complete results were obtained for 767 of them. 662 pts were classified as EPCH and 429 were randomized in UNIRAD. 233 pts with EPCH and 105 pts with EPclin low risk (EPCL) were not randomized but followed up for iDFS. Statistical analysis: Kaplan-Meier estimates the association of the integrated molecular-clinico-pathologic EPclin score, and the 12-gene molecular EP score, with iDFS (primary endpoint) and dMFS (secondary endpoint). Independent prognostic added value of EPclin score was tested in a multivariate Cox model after adjusting on tumor characteristics (Grade and T, N). A two-sided p-value less than 0.05 considered as statistically significant, 95% confidence intervals reported with HR. Results: Median follow-up of the cohort was 36.6 mo (0-69) since EndoPredict test. As for the whole population, there was no significant difference in iDFS between treatment arms in the randomized EPCH group. On the other hand, EPclin was an independent prognostic factor for iDFS. 36 mo relapse rate from testing for patients in the EPCL group and the EPCH group was 0% and 7%, respectively (HR supposing continuous EPclin score: 2.36, 95%CI: 1.7-3.3, p &amp;lt; .0001). This difference remained significant when assessed in a cox model with tumor size, number of positive nodes and tumor grade (HR: 1.96, 95%CI: 1.32-2.9, p=0.0008). Furthermore, EPclin results was independently correlated to distant metastatic free survival: 36 mo dMFS for patient in the EPCL and EPCH group was 100% and 94%, respectively (adjusted HR: 2.13, 95%CI:11.3-3.4, p = .0014). Of interest when assessing prognostic of patients within quartiles of EPclin Score (&amp;lt;3.6; 3.6-4.1; ≥4.1-4.8; ≥ 4.8), 36 mo iDFS was 99%; 95%; 94% and 86%, respectively. Conclusion: These prospective results confirm the significance of EPclin score as an independent prognostic parameter in node positive ER+/HER2- eBC patients receiving standard adjuvant treatment. This information can be of importance for selection of specific adjuvant intervention, particularly chemotherapy and new targeted therapy. Further analysis on the EP score will be presented at the meeting. Citation Format: Frederique Penault-Llorca, Florence Dalenc, Sylvie Chabaud, Paul Cottu, Djelila Allouache, David Cameron, Jean-Philippe Jacquin, Julien Grenier, Laurence Venat Bouvet, Apurna Jegannathen, Mario Campone, Francesco Del Piano, Marc Debled, Anne-Claire Hardy-Bessard, Sylvie Giacchetti, Philippe Barthelemy, Laure Kaluzinski, Audrey Mailliez, Marie-Ange Mouret-Reynier, Eric Legouffe, Anne Cayre, Mathilde Martinez, Catherine Delbaldo, Delphine Mollon-Grange, E. Jane Macaskill, Matthew Sephton, Laëtitia Stefani, Blaha Belgadi, Matthew Winter, Hubert Orfeuvre, Magali Lacroix-Triki, Herve Bonnefoi, Judith Bliss, Jean-Luc Canon, Jerome Lemonnier, Fabrice Andre, Thomas Bachelot. Prognostic value of EndoPredict test in patients screened for UNIRAD, a UCBG randomized, double blind, phase III international trial evaluating the addition of everolimus (EVE) to adjuvant hormone therapy (HT) in women with high risk HR+, HER2- early breast cancer (eBC) [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 PD9-08.

FDA Approval Summary: Abemaciclib With Endocrine Therapy for High-Risk Early Breast Cancer.

The US Food and Drug Administration approved abemaciclib in combination with endocrine therapy (ET) for the adjuvant treatment of adult patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative, node-positive, early breast cancer (EBC) at high risk of recurrence and a Ki-67 score ≥ 20%. The approval was based on monarchE, a phase III, open-label, 2-cohort, multicenter trial of patients with EBC randomly assigned to receive abemaciclib plus ET (n = 2,808) or ET alone (n = 2,829). Abemaciclib was given at 150 mg orally twice daily for 2 years. Invasive disease-free survival (IDFS) in the intent-to-treat population was statistically significant at the second IDFS interim analysis (IA; March 2020; hazard ratio [HR; 95% CI], 0.747 [0.598 to 0.932]; P = .0096); however, only 12.5% of patients had completed adjuvant therapy, and the HR for overall survival (OS) was > 1. A prespecified, controlled analysis of IDFS in patients with Ki-67 ≥ 20% in cohort 1 was statistically significant at the final IDFS analysis (July 2020; HR [95% CI], 0.643 [0.475 to 0.872]; P = .0042). At the first OS IA (April 2021), the majority of patients had completed adjuvant therapy, IDFS remained consistent, and potential detriment in OS was not observed for this subgroup (HR [95% CI], 0.767 [0.511 to 1.152]). The HR for OS in the intent-to-treat population at OS IA remained > 1 (HR [95% CI], 1.091 [0.818 to 1.455]). More patients in the abemaciclib plus ET arm experienced treatment emergent adverse events (all grades 98.4% v 88.8%, grade 3 ≥ 49.7% v 16.3%). The approval of abemaciclib in adjuvant EBC was limited to patients with high risk of recurrence and Ki-67 ≥ 20%, given their favorable benefit:risk with a statistically significant IDFS advantage and no observed detriment on survival.

Abemaciclib With Endocrine Therapy in the Treatment of High-Risk Early Breast Cancer: ASCO Optimal Adjuvant Chemotherapy and Targeted Therapy Guideline Rapid Recommendation Update.

ASCO Rapid Recommendations Updates highlight revisions to select ASCO guideline recommendations as a response to the emergence of new and practice-changing data. The rapid updates are supported by an evidence review and follow the guideline development processes outlined in the ASCO Guideline Methodology Manual. The goal of these articles is to disseminate updated recommendations, in a timely manner, to better inform health practitioners and the public on the best available cancer care options.

Machine Learning Frameworks to Predict Neoadjuvant Chemotherapy Response in Breast Cancer Using Clinical and Pathological Features.

Neoadjuvant chemotherapy (NAC) is used to treat locally advanced breast cancer (LABC) and high-risk early breast cancer (BC). Pathological complete response (pCR) has prognostic value depending on BC subtype. Rates of pCR, however, can be variable. Predictive modeling is desirable to help identify patients early who may have suboptimal NAC response. Here, we test and compare the predictive performances of machine learning (ML) prediction models to a standard statistical model, using clinical and pathological data. Clinical and pathological variables were collected in 431 patients, including tumor size, patient demographics, histological characteristics, molecular status, and staging information. A standard multivariable logistic regression (MLR) was developed and compared with five ML models: k-nearest neighbor classifier, random forest (RF) classifier, naive Bayes algorithm, support vector machine, and multilayer perceptron model. Model performances were measured using a receiver operating characteristic (ROC) analysis and statistically compared. MLR predictors of NAC response included: estrogen receptor (ER) status, human epidermal growth factor-2 (HER2) status, tumor size, and Nottingham grade. The strongest MLR predictors of pCR included HER2+ versus HER2- BC (odds ratio [OR], 0.13; 95% CI, 0.07 to 0.23; P < .001) and Nottingham grade G3 versus G1-2 (G1-2: OR, 0.36; 95% CI, 0.20 to 0.65; P < .001). The area under the curve (AUC) for the MLR was AUC = 0.64. Among the various ML models, an RF classifier performed best, with an AUC = 0.88, sensitivity of 70.7%, and specificity of 84.6%, and included the following variables: menopausal status, ER status, HER2 status, Nottingham grade, tumor size, nodal status, and presence of inflammatory BC. Modeling performances varied between standard versus ML classification methods. RF ML classifiers demonstrated the best predictive performance among all models.