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FGFR alterations in different cohorts

PDF file - 68K, Expression and eQTL status of the patient/LCL overlap genes and SNPs.

Supplementary Data from Acquired FGFR and FGF Alterations Confer Resistance to Estrogen Receptor (ER) Targeted Therapy in ER+ Metastatic Breast Cancer

Supplemental methods, results, figures, tables, and references

Purpose: Fulvestrant is an estrogen receptor (ER) antagonist and an approved treatment for metastatic estrogen receptor–positive (ER+) breast cancer. With the exception of ER levels, there are no established predictive biomarkers of response to single-agent fulvestrant. We attempted to identify a gene signature of response to fulvestrant in advanced breast cancer.Experimental Design: Primary tumor samples from 134 patients enrolled in the phase III CONFIRM study of patients with metastatic ER+ breast cancer comparing treatment with either 250 mg or 500 mg fulvestrant were collected for genome-wide transcriptomic analysis. Gene expression profiling was performed using Affymetrix microarrays. An exploratory analysis was performed to identify biologic pathways and new signatures associated with response to fulvestrant.Results: Pathway analysis demonstrated that increased EGF pathway and FOXA1 transcriptional signaling is associated with decreased response to fulvestrant. Using a multivariate Cox model, we identified a novel set of 37 genes with an expression that is independently associated with progression-free survival (PFS). TFAP2C, a known regulator of ER activity, was ranked second in this gene set, and high expression was associated with a decreased response to fulvestrant. The negative predictive value of TFAP2C expression at the protein level was confirmed by IHC.Conclusions: We identified biologic pathways and a novel gene signature in primary ER+ breast cancers that predicts for response to treatment in the CONFIRM study. These results suggest potential new therapeutic targets and warrant further validation as predictive biomarkers of fulvestrant treatment in metastatic breast cancer. Clin Cancer Res; 22(23); 5755–64. ©2016 AACR.

Contains supplementary tables and methods

Supplementary Tables

Supplementary Data from A Distinct Chromatin State Drives Therapeutic Resistance in Invasive Lobular Breast Cancer

Figure S1. REMARK diagram Figure S2. NanoString Tumor Inflammation Signature by breast cancer intrinsic subtype Figure S3. NanoString individual gene expression changes by cohort Table S1. Pre-treatment immune microenvironment and response to preoperative therapy Table S2. Tissue-based immune biomarkers in patients with pathologic complete response Table S3. References for classification of genes as M1-like or M2-like

Supplementary Table from The Phase II MutHER Study of Neratinib Alone and in Combination with Fulvestrant in HER2-Mutated, Non-amplified Metastatic Breast Cancer

Supplemental Figure 1. Consort Diagram 03-311. Supplemental Figure 2. Consort Diagram 211B. Supplemental Figure 3. Subtype-specific changes in Immune Index upon brief-exposure to nab-paclitaxel in the 211B trial. Supplemental Figure 4. Evaluation of the Immune Index upon brief-exposure to trastuzumab in the 03-311 and 211B trials according to ER/PR status. Supplemental Figure 5. Evaluation of the Immune Index upon brief-exposure to nab-paclitaxel in the 211B trial according to ER/PR status. Supplemental Figure 6. Correlation between Immune Index and tumor content. Supplemental Figure 7. Association of CD4+ Th1 and Treg signatures with response. Supplemental Table 1. Immune Index genes discriminative of response at the post-exposure timepoint in the discovery (03-311) and validation (211B) datasets. Supplemental Table 2. Immune cell subset signatures discriminative of response at baseline and post-exposure timepoints in the discovery (03-311) and validation (211B) datasets. Supplemental Table 3. CD8+ T-cell cytolytic activity genes discriminative of response at the post-exposure timepoint in the discovery (03-311) and validation (211B) datasets.

Purpose:In contrast to recurrence after initial diagnosis of stage I–III breast cancer [recurrent metastatic breast cancer (rMBC)], de novo metastatic breast cancer (dnMBC) represents a unique setting to elucidate metastatic drivers in the absence of treatment selection. We present the genomic landscape of dnMBC and association with overall survival (OS).Experimental Design:Targeted DNA sequencing (OncoPanel) was prospectively performed on either primary or metastatic tumors from 926 patients (212 dnMBC and 714 rMBC). Single-nucleotide variants, copy-number variations, and tumor mutational burden (TMB) in treatment-naïve dnMBC primary tumors were compared with primary tumors in patients who ultimately developed rMBC, and correlated with OS across all dnMBC.Results:When comparing primary tumors by subtype, MYB amplification was enriched in triple-negative dnMBC versus rMBC (21.1% vs. 0%, P = 0.0005, q = 0.111). Mutations in KMTD2, SETD2, and PIK3CA were more prevalent, and TP53 and BRCA1 less prevalent, in primary HR+/HER2− tumors of dnMBC versus rMBC, though not significant after multiple comparison adjustment. Alterations associated with shorter OS in dnMBC included TP53 (wild-type: 79.7 months; altered: 44.2 months; P = 0.008, q = 0.107), MYC (79.7 vs. 23.3 months; P = 0.0003, q = 0.011), and cell-cycle (122.7 vs. 54.9 months; P = 0.034, q = 0.245) pathway genes. High TMB correlated with better OS in triple-negative dnMBC (P = 0.041).Conclusions:Genomic differences between treatment-naïve dnMBC and primary tumors of patients who developed rMBC may provide insight into mechanisms underlying metastatic potential and differential therapeutic sensitivity in dnMBC. Alterations associated with poor OS in dnMBC highlight the need for novel approaches to overcome potential intrinsic resistance to current treatments.

Supplementary eTables 1-12

Application of MRD testing to healthy donor cfDNA samples. Patient specific panels designed for 14 different patients were pooled together and applied to cfDNA collected from four different healthy donors. Reported are the number of sites where ctDNA was detected. We required at least two sites to call a sample MRD+.

PDF file - 65K, Empirical P-values generated from patient/LCL enrichment analyses using a range of P-value inclusion thresholds for SNP overlap.

PDF file - 73K

Supplementary Tables S1-S3 from Predictors of Resistance to Preoperative Trastuzumab and Vinorelbine for HER2-Positive Early Breast Cancer

Purpose:We had previously reported on the safety and the recommended phase 2 dose (RP2D) of olaparib in combination with the PI3Kα-specific inhibitor alpelisib in patients with high-grade serous ovarian cancer as studied in a phase 1b trial (NCT01623349). Here, we report on the breast cancer cohort from that study.Patients and Methods:Eligible patients had recurrent triple-negative breast cancer (TNBC) or recurrent breast cancer of any subtype with a germline BRCA mutation and were enrolled to a dose-escalation or -expansion cohort. After definition of the RP2D, secondary end points included safety and objective response rate (ORR). Exploratory analyses were performed using circulating-free DNA (cfDNA).Results:Seventeen patients with TNBC were enrolled with a median of three prior lines of chemotherapy. The most common treatment-related grade 3–4 adverse events were hyperglycemia (18%) and rash (12%). The ORR was 18% (23% for patients treated at the RP2D) and 59% had disease control. The median duration of response was 7.4 months. Analysis of cfDNA tumor fractions (TFx) revealed that patients with TFx < 15% after completion of the first cycle had a longer progression-free survival compared with those with TFx ≥ 15% (6.0 vs. 0.9 months; P = 0.0001).Conclusions:Alpelisib in combination with olaparib is tolerable in patients with pre-treated TNBC, with evidence of activity in non-BRCA carriers. cfDNA provided important prognostic information. Results highlight potential synergistic use of a PI3K inhibitor to sensitize HR-proficient (BRCA wild-type) TNBC to PARP inhibition and suggest the potential to expand the use of PARP inhibition beyond BRCA-mutant tumors.

Supplemental Figure 1: Study Schema Supplemental Table 1: Tissue Insulin Receptor Staining

Purpose: Recent data suggest that intrinsic subtype and immune cell infiltration may predict response to trastuzumab-based therapy. We studied the interaction between these factors, changes in immune signatures following brief exposure to trastuzumab, and achievement of pathologic complete response (pCR) to subsequent preoperative trastuzumab and chemotherapy in HER2-positive breast cancer.Experimental Design: In patients enrolled on two multicenter trials (03-311 and 211B), tumor core biopsies were obtained at baseline and after brief exposure to single-agent trastuzumab or nab-paclitaxel. Gene expression profiles were assessed to assign PAM50 subtypes, measure immune cell activation, and were correlated with response.Results: The pCR rate was significantly higher in HER2-enriched tumors in the Discovery, 03-311 (36%, P = 0.043) dataset, as compared with other subtypes, which validated in 211B (50%, P = 0.048). Significant increases in a signature of immune cell admixture (Immune Index) were observed only following brief exposure to trastuzumab in HER2-enriched tumors (Discovery/03-311, P = 0.05; Validation/211B, P = 0.02). Increased Immune Index was predictive of response after brief exposure (03-311, P = 0.03; 211B, P = 0.04), but not at baseline, in addition to increased expression of a CD4+ follicular helper T-cell signature (03-311, P = 0.05; 211B, P = 0.04). Brief exposure to trastuzumab significantly increased gene expression of the T-cell marker PD-1 in HER2-enriched tumors (Discovery/03-311, P = 0.045) and PD-1 positivity by IHC (Validation/211B, P = 0.035).Conclusions: Correlations between pCR rates, increases in Immune Index and markers of T-cell activity following brief exposure to trastuzumab in HER2-enriched tumors provide novel insights into the interaction between tumor biology, antitumor immunity, and response to treatment, and suggest potential clinically useful biomarkers in HER2+ breast cancers. Clin Cancer Res; 22(13); 3249–59. ©2016 AACR.

Purpose:Hormone receptor–positive/HER2-negative (HR+/HER2−) breast cancer is associated with low levels of stromal tumor-infiltrating lymphocytes (sTIL) and PD-L1, and demonstrates poor responses to checkpoint inhibitor therapy. Evaluating the effect of standard chemotherapy on the immune microenvironment may suggest new opportunities for immunotherapy-based approaches to treating HR+/HER2− breast tumors.Experimental Design:HR+/HER2− breast tumors were analyzed before and after neoadjuvant chemotherapy. sTIL were assessed histologically; CD8+ cells, CD68+ cells, and PD-L1 staining were assessed immunohistochemically; whole transcriptome sequencing and panel RNA expression analysis (NanoString) were performed.Results:Ninety-six patients were analyzed from two cohorts (n = 55, Dana-Farber cohort; n = 41, MD Anderson cohort). sTIL, CD8, and PD-L1 on tumor cells were higher in tumors with basal PAM50 intrinsic subtype. Higher levels of tissue-based lymphocyte (sTIL, CD8, PD-L1) and macrophage (CD68) markers, as well as gene expression markers of lymphocyte or macrophage phenotypes (NanoString or CIBERSORT), correlated with favorable response to neoadjuvant chemotherapy, but not with improved distant metastasis-free survival in these cohorts or a large gene expression dataset (N = 302). In paired pre-/postchemotherapy samples, sTIL and CD8+ cells were significantly decreased after treatment, whereas expression analyses (NanoString) demonstrated significant increase of multiple myeloid signatures. Single gene expression implicated increased expression of immunosuppressive (M2-like) macrophage-specific genes after chemotherapy.Conclusions:The immune microenvironment of HR+/HER2− tumors differs according to tumor biology. This cohort of paired pre-/postchemotherapy samples suggests a critical role for immunosuppressive macrophage expansion in residual disease. The role of macrophages in chemoresistance should be explored, and further evaluation of macrophage-targeting therapy is warranted.

Supplementary Figures 1-5

Correlation between IHC and transcript level by microarray

clinicopathologic info

Purpose:HER2 mutations (HER2mut) induce endocrine resistance in estrogen receptor–positive (ER+) breast cancer.Patients and Methods:In this single-arm multi-cohort phase II trial, we evaluated the efficacy of neratinib plus fulvestrant in patients with ER+/HER2mut, HER2 non-amplified metastatic breast cancer (MBC) in the fulvestrant-treated (n = 24) or fulvestrant-naïve cohort (n = 11). Patients with ER-negative (ER−)/HER2mut MBC received neratinib monotherapy in an exploratory ER− cohort (n = 5).Results:The clinical benefit rate [CBR (95% confidence interval)] was 38% (18%–62%), 30% (7%–65%), and 25% (1%–81%) in the fulvestrant-treated, fulvestrant-naïve, and ER− cohorts, respectively. Adding trastuzumab at progression in 5 patients resulted in three partial responses and one stable disease ≥24 weeks. CBR appeared positively associated with lobular histology and negatively associated with HER2 L755 alterations. Acquired HER2mut were detected in 5 of 23 patients at progression.Conclusions:Neratinib and fulvestrant are active for ER+/HER2mut MBC. Our data support further evaluation of dual HER2 blockade for the treatment of HER2mut MBC.

Purpose:Addition of alpelisib to fulvestrant significantly extended progression-free survival in PIK3CA-mutant, hormone receptor–positive (HR+) advanced/metastatic breast cancer in the phase III SOLAR-1 study. The combination of alpelisib and letrozole also had promising activity in phase I studies of HR+ advanced/metastatic breast cancer. NEO-ORB aimed to determine whether addition of alpelisib to letrozole could increase response rates in the neoadjuvant setting.Patients and Methods: Postmenopausal women with HR+, human epidermal growth factor receptor 2-negative, T1c-T3 breast cancer were assigned to the PIK3CA-wild-type or PIK3CA-mutant cohort according to their tumor PIK3CA status, and randomized (1:1) to 2.5 mg/day letrozole with 300 mg/day alpelisib or placebo for 24 weeks. Primary endpoints were objective response rate (ORR) and pathologic complete response (pCR) rate for both PIK3CA cohorts.Results:In total, 257 patients were assigned to letrozole plus alpelisib (131 patients) or placebo (126 patients). Grade ≥3 adverse events (≥5% of patients) in the alpelisib arm were hyperglycemia (27%), rash (12%), and maculo-papular rash (8%). The primary objective was not met; ORR in the alpelisib versus placebo arm was 43% versus 45% and 63% versus 61% in the PIK3CA-mutant and wild-type cohorts, respectively. pCR rates were low in all groups. Decreases in Ki-67 were similar across treatment arms and cohorts. In PIK3CA-mutant tumors, alpelisib plus letrozole treatment induced a greater decrease in phosphorylated AKT versus placebo plus letrozole.Conclusions:In contrast to initial results in advanced/metastatic disease, addition of alpelisib to 24-week neoadjuvant letrozole treatment did not improve response in patients with HR+ early breast cancer.

PDF file - 68K, Positional information and effect sizes of the 24 patient/LCL overlap SNPs.

Supplementary Figure from Phase 1b Clinical Trial with Alpelisib plus Olaparib for Patients with Advanced Triple-Negative Breast Cancer

Purpose: Brain metastases develop in one third of patients with advanced HER2+ breast cancer. Effective therapy for patients with central nervous system (CNS) progression after cranial radiation is extremely limited and represents a major clinical challenge. Lapatinib, an epidermal growth factor receptor/HER2 inhibitor, was associated with regressions of CNS lesions in a small phase 2 trial. The current study was done to further evaluate the CNS activity of lapatinib. The study was later amended to allow patients who progressed on lapatinib the option of receiving lapatinib plus capecitabine.Experimental Design: Eligible patients had HER2+ breast cancer, progressive brain metastases, prior trastuzumab, and cranial radiotherapy. The primary end point was CNS objective response, defined as ≥50% volumetric reduction of CNS lesion(s) in the absence of increasing steroid use, progressive neurologic signs and symptoms, or progressive extra-CNS disease.Results: Two-hundred and forty-two patients entered the study. CNS objective responses to lapatinib were observed in 6% of patients. In an exploratory analysis, 21% of patients experienced a ≥20% volumetric reduction in their CNS lesions. An association was observed between volumetric reduction and improvement in progression-free survival and neurologic signs and symptoms. Of the 50 evaluable patients who entered the lapatinib plus capecitabine extension, 20% experienced a CNS objective response and 40% experienced a ≥20% volumetric reduction in their CNS lesions.Conclusions: This study confirms the modest CNS antitumor activity of lapatinib. Additional responses were observed with the combination of lapatinib and capecitabine. Further studies of lapatinib-based regimens for CNS metastases from HER2+ breast cancer are warranted.

Complete exome data

Purpose: To assess pathologic complete response (pCR), clinical response, feasibility, safety, and potential predictors of response to preoperative trastuzumab plus vinorelbine in patients with operable, human epidermal growth factor receptor 2 (HER2)–positive breast cancer.Experimental Design: Forty-eight patients received preoperative trastuzumab and vinorelbine weekly for 12 weeks. Single and multigene biomarker studies were done in an attempt to identify predictors of response.Results: Eight of 40 (20%) patients achieved pCR (95% confidence interval, 9-36%). Of 9 additional patients recruited for protocol-defined toxicity analysis, 8 were evaluable; 42 of 48 (88%) patients had clinical response (16 patients, clinical complete response; 26 patients, clinical partial response). T1 tumors more frequently exhibited clinical complete response (P = 0.05) and showed a trend to exhibit pCR (P = 0.07). Five (13%) patients experienced grade 1 cardiac dysfunction during preoperative treatment. Neither HER2 nor estrogen receptor status changed significantly after exposure to trastuzumab and vinorelbine. RNA profiling identified three top-level clusters by unsupervised analysis. Tumors with extremes of response [pCR (n = 3) versus nonresponse (n = 3)] fell into separate groups by hierarchical clustering. No predictive genes were identified in pCR tumors. Nonresponding tumors were more likely to be T4 stage (P = 0.02) and express basal markers (P < 0.00001), growth factors, and growth factor receptors. Insulin-like growth factor-I receptor membrane expression was associated with a lower response rate (50% versus 97%; P = 0.001).Conclusions: Preoperative trastuzumab plus vinorelbine is active and well tolerated in patients with HER2-positive, operable, stage II/III breast cancer. HER2-overexpressing tumors with a basal-like phenotype, or with expression of insulin-like growth factor-I receptor and other proteins involved in growth factor pathways, are more likely to be resistant to this regimen.

Purpose:We report results from a phase II study assessing the efficacy of the WEE1 inhibitor adavosertib with cisplatin in metastatic triple-negative breast cancer (mTNBC).Patients and Methods:Patients with mTNBC treated with 0–1 prior lines of chemotherapy received cisplatin 75 mg/m2 i.v. followed 21 days later by cisplatin plus adavosertib 200 mg oral twice daily for five doses every 21 days. The study had 90% power to detect the difference between null (20%) and alternative (40%) objective response rates (ORR) with a one-sided type I error of 0.1: an ORR >30% was predefined as making the regimen worthy of further study. RNA sequencing and multiplex cyclic immunofluorescence on pre- and post-adavosertib tumor biopsies, as well as targeted next-generation sequencing on archival tissue, were correlated with clinical benefit, defined as stable disease ≥6 months or complete or partial response.Results:A total of 34 patients initiated protocol therapy; median age was 56 years, 2 patients (6%) had BRCA2 mutations, and 14 (41%) had one prior chemotherapy. ORR was 26% [95% confidence interval (CI), 13–44], and median progression-free survival was 4.9 months (95% CI, 2.3–5.7). Treatment-related grade 3–5 adverse events occurred in 53% of patients, most commonly diarrhea in 21%. One death occurred because of sepsis, possibly related to study therapy. Tumors from patients with clinical benefit demonstrated enriched immune gene expression and T-cell infiltration.Conclusions:Among patients with mTNBC treated with 0–1 prior lines, adavosertib combined with cisplatin missed the prespecified ORR cutoff of >30%. The finding of immune-infiltrated tumors in patients with clinical benefit warrants validation.

Digital droplet PCR (ddPCR) testing for single mutation in dilution series. (A) The observed VAFs of HapMap serial dilutions measured by using a ddPCR assay for a single mutation (with three replicates) vs. the expected VAFs; (B) The representative ddPCR raw data and fluorescence intensity thresholds for determining positive or negative droplets.

PFS and RORP classifier

Purpose:Exercise after breast cancer diagnosis is associated with lower cancer-specific mortality, but the biological mechanisms through which exercise impacts breast cancer are not fully understood. The Pre-Operative Health and Body (PreHAB) Study was a randomized window-of-opportunity trial designed to test the impact of exercise on Ki-67, gene expression, and other biomarkers in women with breast cancer.Experimental Design:Inactive women with newly diagnosed breast cancer were randomized to an exercise intervention or mind–body control group, and participated in the study between enrollment and surgery (mean 29.3 days). Tumor and serum were collected at baseline and surgery.Results:Forty-nine women were randomized (27 exercise, 22 control). At baseline, mean age was 52.6, body mass index was 30.2 kg/m2, and exercise was 49 minutes/week. Exercise participants significantly increased exercise versus controls (203 vs. 23 minutes/week, P < 0.0001). There were no differences in changes of expression of Ki-67, insulin receptor, and cleaved caspase-3 in exercise participants versus controls. KEGG pathway analysis demonstrated significant upregulation of 18 unique pathways between the baseline biopsy and surgical excision in exercise participants and none in control participants (q < 0.1). Top-ranked pathways included several implicated in immunity and inflammation. Exploratory analysis of tumor immune infiltrates demonstrated a trend toward a decrease in FOXP3+ cells in exercise versus control participants over the intervention period (P = 0.08).Conclusions:A window-of-opportunity exercise intervention did not impact proliferation but led to alterations in gene expression in breast tumors, suggesting that exercise may have a direct effect on breast cancer.See related commentary by Koelwyn and Jones, p. 5179

Biopsy purity and ploidy

TS1-4

Supplementary Data from Multicenter Phase II Study of Lapatinib in Patients with Brain Metastases from HER2-Positive Breast Cancer

Technical performance of the MRD Assay. All samples from early stage breast cancer cohort. Includes plasma cfDNA and buffy coat gDNA samples. Samples from the same patient and probed with the same panel are represented independently. (A) On target fraction calculated from Picard CollectHsMetrics and using pct_selected_bases. (B) Coefficient of variation of duplex fragment depth across fingerprint sites. (C) Fold 80 base penalty score for duplex fragment depth across fingerprint sites. (D, E) Error rate comparison between conventional sequencing (requiring Q20 base quality and removing duplicate fragments) and our duplex sequencing with added filters (see methods). (F) Fraction of total duplexes after downsampling raw reads. We considered a sample to be saturated if it still contained at least 95% of its duplexes after downsampling to 80% of its raw reads.

BackgroundA growing number of lifestyle interventions are being developed to promote weight loss and adoption of a healthful lifestyles among breast cancer survivors; yet Black and Latina women remain underrepresented.PurposeWe performed a scoping review of the available peer-reviewed literature to describe and compare the content, design, methods, and primary outcomes of current diet and/or physical activity (PA) interventions after a breast cancer diagnosis among Black and Latina women.MethodsWe queried PubMed, EMBASE, CINAHL, MEDLINE, and Clinicaltrials.gov up to October 1, 2022, to identify all randomized controlled trials of diet and/or PA after diagnosis of breast cancer with a majority (>50%) of Black or Latina participants.ResultsTwenty-two randomized controlled trials were included in this review (five efficacy, twelve pilot, five on-going). Nine trials were among Latinas (two diet, four PA, and three diet/PA), six among Blacks (one PA and five diet/PA) and seven included both populations (five PA and two diet/PA), all of which examined different endpoints. Two of the five efficacy studies achieved their a priori outcome (one diet trial improved short term dietary intake; one PA trial achieved clinically significant improvements in metabolic syndrome score), both in Latinas. Eight pilot trials intervened on both diet and PA and three of them found favorable behavioral changes. Three (two for Latinas and one for Blacks) out of the nine diet and PA trials and three (all for Latinas) efficacy trials incorporated a culturally focused approach (i.e., traditional foods, music, Spanish content, bicultural health coaches, spirituality). Overall, four trials, including one efficacy trial, had one-year follow-up data, with three finding sustained behavior change. Electronic/mobile components were incorporated in five trials and one involved informal care givers. Most of the trials were geographically limited to the Northeast USA (n=8, NY, NC, DC, NJ) and Texas (n=4).ConclusionsMost of the trials we identified were pilot or feasibility studies and of short duration, demonstrating the need for large randomized controlled efficacy lifestyle interventions among Black and Latina breast cancer survivors. Culturally tailored programing was limited but is an important component to incorporate in future trials in these populations.

PurposeTo examine circulating tumor DNA (ctDNA) and its association with residual cancer burden (RCB) using an ultrasensitive assay in patients with triple-negative breast cancer (TNBC) receiving neoadjuvant chemotherapy (NAT).Patients and MethodsWe identified responders (RCB-0/1) and matched non-responders (RCB-2/3) from the phase II TBCRC 030 prospective study of neoadjuvant paclitaxel vs. cisplatin in TNBC. We collected plasma samples at baseline, three weeks, and twelve weeks (end of therapy). We created personalized ctDNA assays utilizing MAESTRO mutation enrichment sequencing. We explored associations between ctDNA and RCB status and disease recurrence.ResultsOf 139 patients, 68 had complete samples and no additional NAT. Twenty-two were responders and 19 of those had sufficient tissue for whole-genome sequencing. We identified an additional 19 non-responders for a matched case-control analysis of 38 patients using a MAESTRO ctDNA assay tracking 319-1000 variants (median 1000) to 114 plasma samples from 3 timepoints. Overall, ctDNA positivity was 100% at baseline, 79% at week 3, and 55% at week 12. Median tumor fraction (TFx) was 3.7 × 10−4(range: 7.9 × 10−7to 4.9 × 10−1). TFx decreased 285-fold from baseline to week 3 in responders and 24-fold in non-responders. Week 12 ctDNA clearance correlated with RCB: clearance was observed in 10/11 patients with RCB-0, 3/8 with RCB-1, 4/15 with RCB-2, and 0/4 with RCB-3. Among 6 patients with known recurrence five had persistent ctDNA at week 12.ConclusionNAT for TNBC reduced ctDNA TFx by 285-fold in responders and 24-fold in non-responders. In 58% (22/38) of patients, ctDNA TFx dropped below the detection level of a commercially available test, emphasizing the need for sensitive tests. Additional studies will determine if ctDNA-guided approaches can improve outcomes.

PURPOSE CALGB 40603 ( NCT00861705 ), a 2 × 2 randomized phase II trial, demonstrated that adding carboplatin or bevacizumab to weekly paclitaxel (wP) followed by doxorubicin and cyclophosphamide significantly increased the pathologic complete response (pCR) rate in stage II-III triple-negative breast cancer. We now report long-term outcomes (LTOs) and correlative science end points. PATIENTS AND METHODS The Kaplan-Meier method was used to estimate LTOs in 443 patients who initiated study treatment. Log-rank tests and Cox proportional hazards models evaluated the impact of clinical characteristics, pathologic response, calculated residual cancer burden (RCB) in patients with residual disease (RD), treatment assignment, and dose delivery during wP on LTOs, including event-free survival (EFS). Genomic predictors of treatment response and outcomes were assessed on pretreatment tumor samples by mRNA sequencing. RESULTS Among baseline characteristics, only the clinical stage was associated with LTOs. At a median follow-up of 7.9 years, LTOs were not significantly improved with either carboplatin or bevacizumab, overall or in patients with basal-like subtype cancers by genomic analysis. Patients with pCR (n = 205, 46.3%) had significantly higher 5-year EFS (85.5% v 56.6%, log-rank P < .0001) and overall survival (87.9% v 63.4%, P < .0001) rates compared with patients with RD, even those with RCB class I. Among clinical and genomic features, evidence of immune activation, including tumor-infiltrating lymphocytes and low B-cell receptor evenness, was associated with pCR and improved EFS. CONCLUSION Despite higher pCR rates, neither carboplatin nor bevacizumab appeared to improve LTOs although the study was not powered to assess these secondary end points. pCR was associated with superior LTOs even when compared with minimal RD. Markers of immune activation in pretreatment tumor biopsies were independently associated with higher pCR rates and improved survival.

In a previous analysis of this phase 3 trial, first-line ribociclib plus letrozole resulted in significantly longer progression-free survival than letrozole alone among postmenopausal patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. Whether overall survival would also be longer with ribociclib was not known.Here we report the results of the protocol-specified final analysis of overall survival, a key secondary end point. Patients were randomly assigned in a 1:1 ratio to receive either ribociclib or placebo in combination with letrozole. Overall survival was assessed with the use of a stratified log-rank test and summarized with the use of Kaplan-Meier methods after 400 deaths had occurred. A hierarchical testing strategy was used for the analysis of progression-free survival and overall survival to ensure the validity of the findings.After a median follow-up of 6.6 years, 181 deaths had occurred among 334 patients (54.2%) in the ribociclib group and 219 among 334 (65.6%) in the placebo group. Ribociclib plus letrozole showed a significant overall survival benefit as compared with placebo plus letrozole. Median overall survival was 63.9 months (95% confidence interval [CI], 52.4 to 71.0) with ribociclib plus letrozole and 51.4 months (95% CI, 47.2 to 59.7) with placebo plus letrozole (hazard ratio for death, 0.76; 95% CI, 0.63 to 0.93; two-sided P = 0.008). No new safety signals were observed.First-line therapy with ribociclib plus letrozole showed a significant overall survival benefit as compared with placebo plus letrozole in patients with HR-positive, HER2-negative advanced breast cancer. Median overall survival was more than 12 months longer with ribociclib than with placebo. (Funded by Novartis; MONALEESA-2 ClinicalTrials.gov number, NCT01958021.).

Background: Platinum agents induce DNA crosslinking and cause accumulation of genotoxic stress, which leads to immune activation via IFN-γ signaling, making the combination with nivolumab (PD-1 antibody) an attractive strategy to enhance the benefit of either agent alone in metastatic triple-negative breast cancer (mTNBC). Methods: In this phase II open-label, investigator-initiated, multicenter trial, patients with unresectable locally advanced or mTNBC treated with 0-1 prior lines of chemotherapy in the metastatic setting were randomized 1:1 to carboplatin (AUC 6) with or without nivolumab (360 mg) IV every 3 weeks. Stratification factors included: germline BRCA (gBRCA) status, prior neo/adjuvant platinum, and number of prior lines of metastatic therapy. After approval of PD-L1 inhibition for mTNBC, the study was amended to include first-line mTNBC only and PD-L1 status was added as a stratification factor. Patients randomized to carboplatin alone were allowed to crossover at progression to receive nivolumab (+ nab-paclitaxel post-amendment). The primary objective was to compare progression-free survival (PFS) per RECIST 1.1 criteria of carboplatin with or without nivolumab in first-line mTNBC in the intent-to-treat (ITT) population. Key secondary objectives were objective response rate (ORR), overall survival (OS), clinical benefit rate, and duration and time to objective response. PD-L1 status was confirmed centrally using the SP142 Ventana assay (positive, ≥1% IC). Paired research biopsies at baseline, on-treatment and at progression were performed, if safely accessible. The trial closed to accrual prior to reaching target accrual due to approval of PD-1 inhibition in combination with platinum-based chemotherapy for PD-L1+ mTNBC. Results: Between 1/30/2018 and 12/9/2020, 78 patients enrolled. Three patients did not receive protocol treatment, and the safety analysis was conducted among the 75 that received any treatment; 37 received carboplatin + nivolumab (Arm A), 38 received carboplatin alone (Arm B). Median age was 59.1 yrs (range: 25.4-75.8). Four patients (5.3%) had a known gBRCA1/2 mutation. Sixty-two (82.7%) patients received 0 prior lines (ITT population) and 13 (17.3%) 1 prior line of metastatic therapy. Sixty-seven patients (89.3%) experienced any grade ≥2 treatment-related adverse event (AE). The most frequent AE were platelet count decrease (n=40; 53.3%), anemia (n=36; 48.0%), neutrophil count decrease (n=33; 44.0%) and fatigue (n=24; 32.0%). Grade 3/4 AE were observed in 46 (61.3%) patients, and there was one grade 5 AE (COVID19 pneumonia). Any grade ≥2 immune-related AE (irAE) were observed in 25 of the 37 (67.6%) patients treated with carboplatin + nivolumab. Grade 3/4 irAE were observed in 11 (29.7%) patients. In the ITT population (32 on Arm A; 30 on Arm B), median PFS was 4.2 months with carboplatin + nivolumab, and 5.5 months with carboplatin (stratified HR 0.98, 95% CI [0.51 - 1.88]; p=0.95). ORR was 25% vs. 23.3%, respectively. At a median follow-up of 23.5 months, median OS was 17.5 months vs. 10.7 months (stratified HR 0.63, 95% CI [0.32 - 1.24]; p=0.18). In patients with PD-L1+ mTNBC (13 on Arm A; 11 on Arm B), median PFS was 8.3 months and 4.7 months, respectively (stratified HR 0.63, 95% CI [0.21 - 1.89]; p=0.41). ORR was 23.1% vs. 27.3%, respectively. Median OS was 17.5 months vs. 9.6 months (stratified HR 0.59, 95% CI [0.20 - 1.75]; p=0.34). Conclusions: Addition of nivolumab to carboplatin in patients with previously untreated mTNBC, unselected by PD-L1 status, did not significantly improve PFS. A trend toward improved PFS and OS was observed in patients with PD-L1+ mTNBC. Tissue, blood and intestinal microbiome biomarker analyses are planned; bulk tumor and single-cell sequencing, and TCR sequencing in peripheral blood are ongoing. Clinical trial information: NCT03414684. Citation Format: Ana C Garrido-Castro, Noah Graham, Kevin Bi, Jihye Park, Jingxin Fu, Tanya Keenan, Edward Thomas Richardson, Ricardo Pastorello, Paulina Lange, Victoria Attaya, Robert Wesolowski, Natalie Sinclair, Zarah Lucas, Steve Lo, Nadine Tung, Meredith Faggen, Peter A Kaufman, Caroline C Block, Fred Briccetti, Madhavi Toke, Wendy Chen, Kai Wucherpfennig, Sascha Marx, Ye Tian, Judith Agudo, Jennifer L Guerriero, Stuart Schnitt, Nancy U Lin, Eric P Winer, Elizabeth A Mittendorf, Nabihah Tayob, Eliezer Van Allen, Sara M Tolaney. A randomized phase II trial of carboplatin with or without nivolumab in metastatic 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 P2-14-18.

Background: Triple-negative breast cancer (TNBC) is associated with high risk of distant recurrence and death. At present, our ability to estimate risk of death from causes other than breast cancer is limited. Particularly among elderly patients (pts), who have been historically underrepresented in clinical trials. In pts with TNBC, assessing both risks is important for our treatment recommendations. The aim of this study was to evaluate risk of BCSM and non-BCSM in TNBC by patient (pt) and tumor characteristics. Methods: Using data from the Surveillance, Epidemiology, and End Results (SEER) program, we identified women diagnosed with non-metastatic invasive TNBC between 2010-2016. Fine and Gray regression was used to evaluate the association of BCSM with pre-specified variables including pt age, tumor size (T), nodal status (N), and tumor grade, while considering deaths from other causes as competing events. We then estimated cumulative risk of BCSM, non-BCSM and all-cause mortality within subgroups defined by baseline clinical and pathologic variables. We conducted a subset analysis of N0 pts older than 50 years, given that we anticipated this subgroup would have the most clinically useful balance between BCSM and non-BCSM. Results: We included 37,293 pts. Age distribution was: 27.1% 80 years vs 50-69 years (Hazard ratio [HR] 1.62; 95% CI, [1.45 - 1.80]), T4 vs T1a (HR 8.51; 95% CI, [6.20 - 11.68]), N3 vs N0 (HR 6.31; 95% CI, [5.70 - 7.00]) and grade III/IV vs grade I (HR 2.10; 95% CI, [1.44 - 3.07]). The cumulative risk of BCSM in year 0-7 was 10.7% for N0, 27.9% for N1, 46.4% for N2 and 64.0% for N3. In contrast, the cumulative risk of non-BCSM over the same period ranged from 7.5% in N1 to 8.7% in N2. The table shows risks of BCSM, non-BCSM and all-cause mortality among pts with N0 disease by age at diagnosis and tumor size. Pts 50-69 years had an increasing cumulative risk of BCSM by tumor size up to 13.0% in those with T2 tumors, while the risk of non-BCSM ranged from 4.8% to 5.9%. Pts aged 70-79 years with T1a/b, N0 tumors had risks of BCSM that were approximately 60% lower than the risks of non-BCSM. In pts aged ≥80 years, the risk of non-BCSM increased and is significantly higher than BCSM in patients with T1b-T2 disease. Conclusions: The risk of BCSM in TNBC depends on traditional clinicopathologic factors and is in general, much higher than the risk of non-BCSM. However, the high risk of non-BCSM among older pts is substantial which needs to be taken into consideration when making treatment recommendations. An interactive tool to estimate risks of BCSM, non-BCSM and all-cause mortality for TNBC will be presented at the meeting. BCSMnon-BCSMAll-cause mortalityCumulative risk (%) and 95% CICumulative risk (%) and 95% CICumulative risk (%) and 95% CIyears 0-7years 0-7years 0-7Tumor size among age 50-69, N0 onlyT1a2.6 (1.0 - 4.3)5.9 (3.2 - 8.6)8.5 (5.3 - 11.6)T1b3.9 (2.8 - 5.0)4.8 (3.3 - 6.3)8.7 (6.9 - 10.5)T1c8.1 (6.9 - 9.4)4.8 (3.9 - 5.8)13.0 (11.4 - 14.5)T213.0 (11.6 - 14.4)5.5 (4.4 - 6.5)18.5 (16.8 - 20.2)Tumor size among age 70-79, N0 onlyT1a6.1 (0 - 12.7)13.9 (7.0 - 20.9)20.0 (10.2 - 28.7)T1b5.3 (3.0 - 7.7)13.3 (9.0 - 17.7)18.6 (13.7 - 23.3)T1c11.0 (8.7 - 13.4)14.3 (11.4 - 17.2)25.3 (21.7 - 28.8)T221.0 (17.4 - 24.6)17.4 (13.4 - 21.5)38.5 (33.3 - 43.2)Tumor size among age ≥80, N0 onlyT1a6.6 (0 - 19.7)27.0 (11.0 - 43.1)33.7 (11.8 - 50.1)T1b7.1 (2.1 - 12.2)33.2 (23.2 - 43.2)40.3 (28.9 - 49.9)T1c8.4 (5.2 - 11.6)32.7 (26.4 - 39.0)41.1 (34.1 - 47.3)T222.7 (18.1 - 27.3)41.6 (34.2 - 49.1)64.3 (56.0 - 71.1) Citation Format: Jose P Leone, Noah Graham, Julieta Leone, Sara M Tolaney, Bernardo A Leone, Rachel A Freedman, Michael J Hassett, Carlos T Vallejo, Eric P Winer, Nancy U Lin, Nabihah Tayob. Estimating risk of breast cancer-specific mortality (BCSM) and non-BCSM in patients with 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 P2-10-01.

Background: Immunological differences between HER2+ breast tumors that are HR+ versus HR- have not been widely explored. DAPHNe was a single-arm prospective clinical trial enrolling patients with clinical anatomic stage II-III HER2+ breast cancer to neoadjuvant treatment with THP. Here, we examine differential expression of immune-related proteins between HR+/HER2+ and HR-/HER2+ tumors in pre-treatment biopsies from trial participants, and analyze correlates of pathologic response to THP, overall and by HR status. Methods: A baseline research biopsy was required in all participants prior to initiation of neoadjuvant therapy. All patients received 12 weeks of neoadjuvant THP; 5 patients also received neoadjuvant AC given incomplete clinical response to THP, and are excluded from residual cancer burden (RCB) analyses. The trial primary endpoint, feasibility of de-escalation to antibody doublet therapy only (HP) following pCR, was previously reported. Protein expression profiling of baseline research biopsies was performed on the NanoString GeoMx® platform using a 58-protein immune cell profiling panel. Regions of interest (ROI; up to 12 per slide) were identified by a pathologist based on tumor cell, immune cell, and/or T cell presence, and all ROI were segmented into tumor vs stroma. Protein data quality controls were normalized by isotypes. Linear mixed effect models were used for differential expression comparisons; p-values were estimated using Satterthwaite’s method. Results: 97 pre-treatment breast tumor specimens were analyzed: 64 patients had HR+ tumors, 32 HR-, 1 unknown; 67 patients had favorable (RCB 0/1) response to preop therapy, 30 patients had unfavorable response (RCB 2/3). Multiple significant differences were observed between protein expression in HR+ versus HR- tumors (Table 1). Multiple immune cell types, as well as checkpoint proteins PD-L1 and IDO1, were higher in HR- patients, whereas checkpoint proteins B7-H3 and TIM3 were higher in HR+ patients. In the overall population, higher HER2 and PD-L1 expression were significant predictors of favorable RCB response, while higher ER alpha and Bcl-2 expression were significant predictors of unfavorable RCB response (Table 2). Conclusions: As anticipated, the strength of HER2 expression and ER expression were the most significant predictors of favorable and unfavorable RCB response to neoadjuvant THP, respectively. This highly multiplexed protein expression analysis demonstrated significant differences between the immune microenvironment of HR+ and HR- HER2+ breast tumors, implying that distinct immunological targets should be explored in the treatment of HER2+ breast cancer according to HR status. Table 1.Differences between HR+/HER2+ and HR-/HER2+ patientsStroma compartmentTumor compartmentHigher in HR+ER alpha* (fold-change 2.25)ER alpha* (8.94)Fibronectin (1.68)Bcl-2* (1.98)B7-H3 (1.44)Fibronectin* (1.90)PR (1.69)TIM-3 (1.37)Higher in HR-CD27* (fold-change 1.36)IDO1 (1.50)IDO1 (1.77)S100B (1.44)CD45 (1.45)MART1 (1.33)CD3 (1.35)CD20 (1.34)STING (1.33)CD4 (1.30)ICOS (1.30)CD45RO (1.28)CD40 (1.28)CD127 (1.27)VISTA (1.25)PD-L1 (1.24)4-1BB (1.21)*FDR p-value < 0.05 (otherwise, p-value < 0.05). Table 2: Predictors of RCB response Overall populationHigher in RCB 0/1HER2* (fold-change 3.75)PD-L1 (1.25)Higher in RCB 2/3ER alpha* (2.44)Bcl-2 (1.46)HR+/HER2+ patientsStroma compartmentTumor compartmentHigher in RCB 0/1HER2* (fold-change 4.28)HER2* (4.21)CTLA4 (1.64)Higher in RCB 2/3Bcl-2* (2.18)*FDR p-value < 0.05 (otherwise, p-value < 0.05).HR-/HER2+ patients are not shown in Table 2 as only 2 HR- patients had unfavorable RCB response. Citation Format: Adrienne G. Waks, Ying Huang, Tyler Hether, Esther R Ogayo, Sapana Kadel, Jillian Alberti, Sara M Tolaney, Ian E Krop, Prajan Divakar, Otto Metzger, Madison L O'Donnell, Sarah Church, Eric P Winer, Jennifer L. Guerriero, Elizabeth A Mittendorf. Correlation of immune-related protein expression with hormone receptor (HR) status and pathologic response to neoadjuvant paclitaxel/trastuzumab/pertuzumab (THP) among patients with early-stage HER2+ 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 P2-07-03.

Background: The optimal systemic therapy strategy, neoadjuvant vs adjuvant therapy, for patients with small clinically node negative HER2+ breast cancers is uncertain. The goal of this study was to evaluate the incidence of pathologic nodal disease in cT1-2 N0 HER2+ patients, treated with upfront surgery or neoadjuvant chemotherapy (NAC), to better define selection criteria for initial treatment approach. Methods: Our prospectively maintained database was queried for cT1-2 N0 HER2+ breast cancer patients diagnosed 2/12/2015 - 10/13/2020 (after publication of the Adjuvant Paclitaxel and Trastuzumab trial). Patients without axillary surgery were excluded (n =23). HER2 positivity was defined per ASCO/CAP guidelines. Pre-NAC and/or pre-operative axillary ultrasound was not routinely performed. Patient characteristics and rates of pN+ disease were compared by treatment strategy using Chi square and Wilcoxon rank-sum tests. Nodes with isolated tumor cells were considered negative (pN0) in the upfront surgery setting but positive (pN+) after NAC. Logistic regression determined factors associated with pN+ disease. Results: A total of 579 eligible patients were identified; 368 (63.6%) were treated with upfront surgery and 211 (36.4%) with NAC. Upfront surgery patients were older (median 55 years [range 23-88] vs 49 [24-79], p Table 1.Pathologic nodal stage among upfront surgery and NAC patientsUpfront Surgery (N=368)pN+pN0P valuecT category< 0.001T1mi (N=48)6 (10.4%)42 (89.6%)T1a (N=26)3 (11.5%)23 (88.5%)T1b (N=87)7 (8.0%)80 (92.0%)T1c (N=154)38 (24.7%)116 (75.3%)T2 (N=53)19 (35.8%)34 (64.2%)NAC (N=211)ypN+ypN0P valuecT category0.719T1b (N=7)1 (14.3%)6 (85.7%)T1c (N=30)5 (16.7%)25 (83.3%)T2 (N=174)20 (11.5%)154 (88.5%) Citation Format: Anna Weiss, Adrienne G. Waks, Alison Laws, Sara M. Tolaney, Eric P. Winer, Elizabeth A. Mittendorf, Ann H. Partridge, Tari A. King. Pathologic nodal staging and systemic therapy among patients with cT1-2N0 HER2+ breast cancer: A prospective single institution cohort analysis [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 P2-13-02.

Background: While high tumor mutational burden (TMB-H) has been used as a tissue-agnostic biomarker for approval of immune checkpoint inhibitors (ICI), there is a paucity of data regarding efficacy of ICI in TMB-H MBC. The aim of this study was to evaluate if patients with TMB-H HER2-negative MBC benefit from the combination of nivolumab plus ipilimumab. Methods: This is an open-label, single-arm, multicenter, phase 2 study assessing the efficacy of nivolumab 3 mg/kg intravenously (IV) every 14 days plus ipilimumab 1 mg/kg IV every 6 weeks in subjects with TMB-H HER2-negative MBC. Eligible patients were required to have measurable HER2-negative MBC, TMB ≥9 Mut/Mb assessed by a cancer-gene panel evaluating > 300 genes and performed in a CLIA-certified laboratory, and 0-3 prior lines of chemotherapy in the advanced setting. The primary objective was overall response rate (ORR) according to RECIST 1.1. Secondary objectives include safety and tolerability, progression-free survival (PFS), and overall survival (OS). The study followed a two-stage design. In the first stage, 14 patients were enrolled. The study required at least 1 objective response in order to continue to the second stage where an additional 16 patients were enrolled. At least 4 objective responses among the 30 patients would suggest the regimen is worthy of further study. If the true response rate is 25%, the chance that the regimen is declared worthy of further study is > 90%. Tumor biopsies, peripheral blood mononuclear cells, circulating tumor DNA, and stool collection were mandatory and were obtained at baseline and on treatment (end of cycle 1). Results: From February 2019 to June 2021, 31 patients were enrolled across 3 different academic institutions. Among 30 patients who initiated study treatment, the median age was 63 yo, 20 had hormone-receptor positive (HR+) breast cancer and 10 had triple-negative breast cancer (TNBC), and median number of prior lines of chemotherapy was 1.5 (0-3). Among the 10 patients with TNBC, PD-L1 status was known in 7 patients (3 positive and 4 negative). Median TMB was 10.9 Mut/Mb and 16.7% (n = 5) of patients had a TMB ≥14 mut/Mb. After a median follow-up of 9.7 (4.4 - 16.4) months, 4 (13.3%) patients achieved a confirmed objective response (all partial responses) meeting the primary endpoint of this study. The median duration of response has not been reached and 3 of these patients are still progression-free for at least 15 months. Two patients have short follow-up, and one has an unconfirmed partial response and the other has a stable disease at the time of the data cut. Median PFS and OS was respectively 1.4 (95% CI 1.3 - 9.5) months and 8.8 (95% CI 4.2 - not reached). Exploratory analysis did not show a difference in response rate according to HR status and PD-L1 status (data not shown) but tumors with TMB ≥14 mut/Mb had a response rate of 60% vs 4% in the group with TMB between ≥9 and Citation Format: Romualdo Barroso-Sousa, Tianyu Li, Sangeetha Reddy, Leisha A. Emens, Beth Overmoyer, Paulina Lange, Molly K Dilullo, Victoria Attaya, Jeffrey Kimmel, Eric P. Winer, Elizabeth A. Mittendorf, Nabihah Tayob, Sara M. Tolaney. Nimbus: A phase 2 trial of nivolumab plus ipilimumab for patients with hypermutated her2-negative metastatic breast cancer (MBC) [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 GS2-10.

Background The updated combined SOFT+TEXT analysis, after 9 years median follow-up (MFU), revealed that adjuvant E+OFS vs T+OFS significantly improved disease-free survival (DFS) and distant recurrence-free interval (DRFI) but not overall survival (OS) in premenopausal women with HR+ early BC (Francis et al NEJM 2018). Given the high rate of OS in both arms and the long-term risk of relapse in HR+ BC, continued follow-up is key to assessing treatment benefit. We report a planned update analysis including OS with database lock of May 2021, after 13 years MFU.. Methods TEXT and SOFT enrolled premenopausal women with HR+ early BC from November 2003 to April 2011 (2660 in TEXT, 3047 in SOFT intention-to-treat (ITT) populations). TEXT randomized women within 12 weeks of surgery to 5 years E+OFS vs T+OFS; chemotherapy (CT) was optional and concurrent with OFS. SOFT randomized women to 5 years E+OFS vs T+OFS vs T alone, within 12 weeks of surgery if no CT planned, or within 8 months of completing (neo)adjuvant CT. Both trials were stratified by CT use. For the combined analysis of E+OFS vs T+OFS, the primary endpoint was DFS defined as invasive local, regional, distant recurrence, contralateral BC, second malignancy, death. Secondary endpoints included invasive breast cancer-free interval (BCFI), DRFI and OS.. Results: At database lock there were 953 DFS events and 473 deaths among 4690 pts assigned to T+OFS or E+OFS. In the ITT population, DFS, BCFI and DRFI outcomes for pts assigned E+OFS (n=2346) continued to be significantly improved over T+OFS (n=2344). 12-yr DFS was 80.5% vs. 75.9% (4.6% absolute improvement; HR 0.79 95% CI 0.70-0.90), 12-yr BCFI was improved by 4.1% and 12-yr DRFI by 1.8%. At 12 years OS was excellent in both groups, 90.1% in pts assigned E+OFS vs 89.1% in pts assigned T+OFS (HR 0.93; 95% CI, 0.78-1.11). There was heterogeneity of relative treatment effect according to HER2 status. When enrollment commenced, anti-HER2 adjuvant therapy was not standard; 53% of 583 pts with HER2+ tumors received HER2-targeted therapy. Below are Kaplan-Meier 12-yr estimates for patients with HER2 negative tumors by trial and chemotherapy stratum and for those with high-grade tumours, as an example of high-risk feature (Table). There is an emerging OS benefit for E+OFS vs T+OFS in pts with HER2 negative tumors who received chemotherapy in both trials.In pts with HER2-negative tumors, clinically-relevant outcome benefits were also seen in other high-risk subgroups: 12-yr DFS and OS were improved by 7.4% and 2.7%, respectively, in pts with pN1a disease, and by 10.6% and 4.5%, respectively, in those with tumors >2cm. Conclusions After 13 years MFU, adjuvant E+OFS, as compared with T+OFS, shows a sustained reduction in the risk of recurrence, more consistent in HER2 negative patients and in those with high-risk disease features, e.g., indication for adjuvant chemotherapy and G3 tumors. Oncologists may use this information to discuss potential benefits of E+OFS with individual patients. Follow-up continues for 5 additional years. Chemotherapy HER2-negativeSOFTT+OFS (n=424)E+OFS (n=411)Absolute difference12-yr DFS67.4%74.1%6.7%12-yr OS81.1%84.4%3.3%TEXTT+OFS (n=656)E+OFS (n=661)Absolute difference12-yr DFS71.0%78.4%7.4%12-yr OS83.5%86.8%3.3%No chemotherapy HER2-negativeSOFTT+OFS (n=445)E+OFS (n=447)Absolute difference12-yr DFS82.9%88.2%5.3%12-yr OS96.1%96.9%0.9%TEXTT+OFS (n=499)E+OFS (n=492)Absolute difference12-yr DFS80.2%86.7%6.5%12-yr OS95.9%96.2%0.2%G3 HER2-negativeT+OFS (n=423)E+OFS (n=405)Absolute difference12-yr DFS62.7%73.0%10.3%12-yr OS78.1%83.6%5.5% Citation Format: Meredith M Regan, Barbara A Walley, Gini F Fleming, Prudence A Francis, Marco A Colleoni, István Láng, Henry L Gómez, Carlo A Tondini, Harold J Burstein, Matthew P Goetz, Eva M Ciruelos, Vered Stearns, Hervé R Bonnefoi, Silvana Martino, Charles E Geyer, Jr, Claudio Chini, Alessandro M Minisini, Simon Spazzapan, Thomas Ruhstaller, Eric P Winer, Barbara Ruepp, Sherene Loi, Alan S Coates, Aron Goldhirsch, Richard D Gelber, Olivia Pagani. Randomized comparison of adjuvant aromatase inhibitor exemestane (E) plus ovarian function suppression (OFS) vs tamoxifen (T) plus OFS in premenopausal women with hormone receptor-positive (HR+) early breast cancer (BC): update of the combined TEXT and SOFT trials [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 GS2-05.