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Background: Combination chemotherapy (CT) remains a standard of care in advanced breast cancer (ABC) with aggressive disease features (rapidly progressing or highly symptomatic disease, including life-threatening visceral crisis). To date, no data have been published on a head-to-head comparison of CDK4/6 inhibitor (CDK4/6i) + endocrine therapy (ET) vs combination CT in this patient (pt) population. RIGHT Choice, a randomized, open-label, multi-national, Phase II trial, investigated the efficacy and safety of first-line ribociclib (RIB) + ET vs combination CT in pre/perimenopausal pts with HR+/HER2− ABC with aggressive disease (where combination CT is clinically indicated by physician’s judgment). Here we report the results of the primary endpoint of progression-free survival (PFS) and key secondary endpoints from this study. Methods: Pre/perimenopausal pts with HR+/HER2− ABC (>10% estrogen receptor–positive [ER+]) and no prior systemic therapy for ABC were randomized 1:1 to receive either RIB (600 mg daily, 3 weeks on/1 week off) with letrozole/anastrozole + goserelin or investigator’s choice of CT (docetaxel + capecitabine, paclitaxel + gemcitabine, or capecitabine + vinorelbine). Randomization was stratified by presence of liver metastases and whether the disease-free interval (duration from date of complete tumor resection for primary breast cancer lesion to the date of documented disease recurrence) was less than two years. Pts included in the trial had ABC not amenable to curative therapy for which combination CT was clinically indicated by physician’s judgment (i.e., symptomatic visceral metastases, rapid progression of disease or impending visceral compromise, or markedly symptomatic non-visceral disease). Median PFS (mPFS) and median time to treatment failure (mTTF) were evaluated by Kaplan-Meier methods. Overall response rate (ORR) was also analyzed, with quality of life and biomarker analyses planned. RIGHT Choice is registered at ClinicalTrials.gov (NCT03839823). Results: A total of 222 pts (112 RIB + ET; 110 CT) were enrolled from Feb 2019 to Nov 2021. Pts with symptomatic visceral metastases (n=150; 67.6%), rapid disease progression (n=41; 18.5%), and markedly symptomatic non-visceral metastases (n=31; 14.0%) were included. Overall, 116 pts (52.3%) had visceral crisis based on guideline definitions. A majority of pts (n=190; 85.6%) had tumors that were ≥50% ER+. At data cutoff (Apr 12, 2022), median follow-up was 24.1 mo; 45.5% and 23.6% of pts remained on treatment in the RIB + ET arm and combination CT arm, respectively. The primary endpoint was met, with a statistically significant PFS benefit of ≈1 year for RIB + ET vs combination CT (mPFS, 24.0 vs 12.3 mo; hazard ratio, 0.54; 95% CI, 0.36-0.79; P=.0007). OS data were immature at data cutoff. The mTTF was ≈10 mo longer for RIB + ET vs CT (18.6 vs 8.5 mo; hazard ratio, 0.45; 95% CI, 0.32-0.63). The ORR was similar for RIB + ET vs CT (65.2% vs 60.0%). No new safety signals were observed in pts on RIB. Lower rates of treatment-related serious adverse events (AEs; 1.8% vs 8.0%) and lower rates of discontinuation due to treatment-related AEs (7.1% vs 23.0%) were seen with RIB + ET vs CT, respectively. AEs observed with combination CT were consistent with the published data. Conclusions: This analysis demonstrated a statistically significant and clinically meaningful PFS benefit with RIB + ET over combination CT in the first-line pre/perimenopausal pt population with aggressive HR+/HER2− ABC disease. This is the first study comparing a CDK4/6i + ET vs combination CT and demonstrating the superiority of RIB + ET in aggressive HR+/HER2− ABC. This evidence supports RIB+ ET use as a preferred option for this pt population. Citation Format: Yen-Shen Lu, Eznal Izwadi Bin Mohd Mahidin, Hamdy Azim, Yeşim ERALP, Yoon-Sim Yap, Seock-Ah Im, Julie Rihani, James Bowles, Teresa Delgar Alfaro, Jiwen Wu, Melissa Gao, Khemaies Slimane, Nagi El Saghir. Primary results from the randomized Phase II RIGHT Choice trial of premenopausal patients with aggressive HR+/HER2− advanced breast cancer treated with ribociclib + endocrine therapy vs physician’s choice combination chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS1-10.

The therapeutic efficacy of tamoxifen is predominantly mediated by its active metabolites 4-hydroxy-tamoxifen and endoxifen, whose formation is catalyzed by the polymorphic cytochrome P450 2D6 (CYP2D6). Yet, known CYP2D6 polymorphisms only partially determine metabolite concentrations in vivo. We performed the first cross-ancestry genome-wide association study with well-characterized patients of European, Middle-Eastern, and Asian descent (N = 497) to identify genetic factors impacting active and parent metabolite formation. Genome-wide significant variants were functionally evaluated in an independent liver cohort (N = 149) and in silico. Metabolite prediction models were validated in two independent European breast cancer cohorts (N = 287, N = 189). Within a single 1-megabase (Mb) region of chromosome 22q13 encompassing the CYP2D6 gene, 589 variants were significantly associated with tamoxifen metabolite concentrations, particularly endoxifen and metabolic ratio (MR) endoxifen/N-desmethyltamoxifen (minimal P = 5.4E-35 and 2.5E-65, respectively). Previously suggested other loci were not confirmed. Functional analyses revealed 66% of associated, mostly intergenic variants to be significantly correlated with hepatic CYP2D6 activity or expression (ρ = 0.35 to -0.52), and six hotspot regions in the extended 22q13 locus impacting gene regulatory function. Machine learning models based on hotspot variants (N = 12) plus CYP2D6 activity score (AS) increased the explained variability (~ 9%) compared with AS alone, explaining up to 49% (median R2 ) and 72% of the variability in endoxifen and MR endoxifen/N-desmethyltamoxifen, respectively. Our findings suggest that the extended CYP2D6 locus at 22q13 is the principal genetic determinant of endoxifen plasma concentration. Long-distance haplotypes connecting CYP2D6 with adjacent regulatory sites and nongenetic factors may account for the unexplained portion of variability.

Background: Mucinous carcinoma is the third most common histological subtype of breast cancer after ductal and lobular carcinomas, accounting for approximately 3% of invasive breast cancers. Although considered a favourable subtype with de-escalation of treatment recommended in the National Comprehensive Cancer Network guidelines, recurrence can occur and supporting data is limited. We thus examined prognostic factors of pure mucinous breast cancer (PMBC) in an international multicentre cohort study. Methods: Patients diagnosed between January 2000 to December 2015 with hormone receptor-positive HER2-negative stage I to III PMBC, invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) at 6 centers in Singapore, Taiwan, Korea and Japan were evaluated. Cox proportional hazards regression analyses were used to compare relapse-free survival (RFS), distant relapse-free survival (DRFS) and overall survival (OS) by histological subtypes, and to identify prognostic factors for PMBC. Results: Of 23,105 women eligible for analysis, 20,684 had IDC, 1,475 had ILC and 946 had PMBC. The median follow-up was 6.6 years; 5-year RFS, DRFS and OS for PMBC were 94.6%, 96.5% and 98.1% respectively. On multivariable cox regression analyses, PMBC demonstrated superior RFS (hazard ratio [HR] = 0.70, 95% CI: 0.56 - 0.88), DRFS (HR = 0.69, 95% CI: 0.53 - 0.89) and OS (HR = 0.70, 95% CI: 0.52 - 0.93) compared to IDC, while ILC had comparable survival outcomes as IDC. When restricted to only PMBC, significant independent prognostic factors for RFS included ethnicity (vs Chinese, “Others” [non-Chinese/Japanese/Korean, mainly Malay and Indian]: HR = 2.62, 95% CI 1.23 – 5.57), older age (vs < 40 years, >70 years: HR = 3.53, 95% CI 1.67 – 7.46), tumor size (vs T1, T3-4: HR = 2.79, 95% CI 1.45 – 5.37), positive lymph nodes (HR = 2.04, 95% CI: 1.10 – 3.77), use of radiotherapy (HR = 0.54, 95% CI 0.33 – 0.91) and endocrine therapy (HR = 0.31, 95% CI 0.12 – 0.77). On further analysis, the inferior RFS, DRFS and OS in older patients (>70 years) were driven largely by non-breast cancer deaths rather than relapses. Use of endocrine therapy was also associated with superior DRFS (HR = 0.26, 95% CI 0.09 – 0.73) but not OS. In a subgroup analysis, use of chemotherapy was associated with improved DRFS (HR = 0.25, 95% CI 0.08 – 0.82) and OS (HR = 0.07, 95% CI 0.01 – 0.37) with a trend in RFS (HR = 0.41, 95% CI 0.14 – 1.24) for lymph node-positive PMBC; no differences in outcomes were observed for the lymph node-negative subgroup. Conclusions: Larger tumor size, lymph node positivity and ethnicity were significant factors for RFS in PMBC. Use of endocrine therapy was associated with superior RFS and DRFS, while chemotherapy was associated with better DRFS and OS for lymph-node positive PMBC. Citation Format: Ryan Tan, Whee Sze Ong, Kyung-Hun Lee, Seri Park, Jabed Iqbal, Yeon Hee Park, Jeong-Eon Lee, Jong Han Yu, Ching-Hung Lin, Yen-Shen Lu, Makiko Ono, Takayuki Ueno, Yoichi Naito, Tatsuya Onishi, Geok hoon Lim, Su-Ming Tan, Han-Byoel Lee, Jiwon Koh, Han Suk Ryu, Wonshik Han, Veronique Kiak Mien Tan, Fuh-Yong Wong, Seock-Ah Im, Puay Hoon Tan, Yoon-Sim Yap. Prognostic factors in non-metastatic hormone receptor-positive HER2-negative mucinous breast cancer: an international multicentre cohort study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-36.

Purpose:Natural killer (NK) cells exert antibody-dependent cell cytotoxicity (ADCC). We infused expanded, activated autologous NK cells to potentiate trastuzumab-mediated ADCC in patients with HER2-positive malignancies.Patients and Methods:In a phase I trial, patients with treatment-refractory HER2-positive solid tumors received trastuzumab, with or without bevacizumab, and autologous NK cells expanded by 10-day coculture with K562-mb15-41BBL cells. Primary objectives included safety and recommended phase II dose determination; secondary objectives included monitoring NK-cell activity and RECIST antitumor efficacy.Results:In 60 cultures with cells from 31 subjects, median NK-cell expansion from peripheral blood was 340-fold (range, 91–603). NK cells expressed high levels of CD16, the mediator of ADCC, and exerted powerful killing of trastuzumab-targeted cells. In the 22 subjects enrolled in phase I dose escalation, trastuzumab plus NK cells were well tolerated; MTD was not reached. Phase IB (n = 9) included multiple cycles of NK cells (1 × 107/kg) and addition of bevacizumab. Although no objective response was observed, 6 of 19 subjects who received at least 1 × 107/kg NK cells at cycle 1 had stable disease for ≥6 months (median, 8.8 months; range 6.0–12.0). One patient, the only one with the high-affinity F158V CD16 variant, had a partial response. Peripheral blood NK cells progressively downregulated CD16 postinfusion; paired tumor biopsies showed increased NK cells, lymphocytic infiltrates, and apoptosis posttreatment.Conclusions:NK-cell therapy in combination with trastuzumab was well tolerated, with target engagement and preliminary antitumor activity, supporting continued assessment of this approach in phase II trials.

Supplementary data contains list of genes and SNP details

It has been estimated that >1,000 genetic loci have yet to be identified for breast cancer risk. Here we report the first study utilizing targeted next-generation sequencing to identify single-nucleotide polymorphisms (SNP) associated with breast cancer risk. Targeted sequencing of 283 genes was performed in 240 women with early-onset breast cancer (≤40 years) or a family history of breast and/or ovarian cancer. Common coding variants with minor allele frequencies (MAF) >1% that were identified were presumed initially to be SNPs, but further database inspections revealed variants had MAF of ≤1% in the general population. Through prioritization and stringent selection criteria, we selected 24 SNPs for further genotyping in 1,516 breast cancer cases and 1,189 noncancer controls. Overall, we identified the JAK2 SNP rs56118985 to be significantly associated with overall breast cancer risk. Subtype analysis performed for patient subgroups defined by ER, PR, and HER2 status suggested additional associations of the NOTCH3 SNP rs200504060 and the HIF1A SNP rs142179458 with breast cancer risk. In silico analysis indicated that coding amino acids encoded at these three SNP sites were conserved evolutionarily and associated with decreased protein stability, suggesting a likely impact on protein function. Our results offer proof of concept for identifying novel cancer risk loci from next-generation sequencing data, with iterative data analysis from targeted, whole-exome, or whole-genome sequencing a wellspring to identify new SNPs associated with cancer risk. Cancer Res; 77(19); 5428–37. ©2017 AACR.

Supplementary Materials, Figures

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: In addition to inhibiting cell cycle progression, CDK4/6 inhibitors have been found to modulate anti-cancer immune response (Goel S, et al. Nature. 2017;548:471-475). Data from preclinical studies suggested multiple mechanisms—involving changes in both cancer cells and immune cells—by which CDK4/6 inhibition can enhance anti-cancer immunity. These mechanisms include increased antigen presentation, interferon response triggering, and regulatory T-cell suppression. Clinical correlates to preclinical observations have so far been obtained using paired biopsies from neoadjuvant breast cancer trials (Johnston S, et al. J Clin Oncol. 2019;37:178-189; Hurvitz S, et al. Clin Cancer Res. 2020; ;26:566-80). Here, we describe a gene expression analysis of paired pre- and on-treatment biopsies from CLEE011A2115C and CLEE011X2107, two phase I clinical trials evaluating ribociclib in combination with ET in the metastatic breast cancer (MBC) setting. Methods: The nCounter PanCancer IO 360 Panel (NanoString) was used to quantify expression of 770 genes in 7 pairs of tumor samples (baseline vs. cycle 1 day 15) from two phase I trials in the MBC setting (5 patients from CLEE011A2115C and 2 from CLEE011X2107). All patients were treated with ribociclib and an ET. Pairwise differential gene expression analysis of individual genes and previously published immune-related gene signatures was conducted (Bedognetti D, et al. Curr Opin Oncol. 2015;27:433-444). Results: Many genes that were markedly suppressed with treatment (eg, MKI67, MYC, CDK2, CCNB1, TYMS, and DNMT1) were related to proliferation, DNA replication, and G1/S transition of the cell cycle, as expected. Interestingly, expression of numerous genes involved in immune response was increased. These were mostly interferon-regulated genes; particularly, a gene signature indicative of a T cell-inflamed tumor microenvironment (Ayers M, et al. J Clin Invest. 2017;127:2930-2940) was upregulated. Immune-related genes tended to preferentially increase with treatment in patients who later experienced a clinical response. Since bulk RNA from tumor biopsies was analyzed, we could not distinguish whether the observed expression changes reflected increased infiltration by immune cells or an endogenous interferon response in cancer cells. The latter could be triggered by DNMT1 suppression (as previously described), which then promotes T cell-mediated immunity by increasing antigen presentation and chemokine production in cancer cells. Conclusions: This analysis was conducted with a small sample size and is considered hypothesis generating; further investigation is needed. Cell cycle and proliferation markers showed robust suppression by ribociclib-based treatment regimens, as expected. Conversely, a notable increase in immune-related genes was detected that tended to occur preferentially in patients who later experienced more favorable clinical outcomes. Both changes occurred early (cycle 1 day 15). To our knowledge, this is the first clinical biomarker report of immune activation mediated by CDK4/6 inhibition in MBC. Citation Format: Dejan Juric, Chong Ma, Ralph Tiedt, Yoon-Sim Yap, Joanne Chiu, Pamela Munster, Roohi Ismail-Khan, Laura Garcia-Estevez, Ingrid A. Mayer, Carlos Becerra, Nadia Solovieff, Agnes Lteif, Faye Su, Yen-Shen Lu. Upregulation of immune response biomarkers by ribociclib plus endocrine therapy (ET) in paired tumor samples from phase I studies [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 P5-13-18.

Detection of minimal residual disease in patients with cancer, who are in complete remission with no cancer cells detectable, has the potential to improve recurrence-free survival through treatment selection. Studies analyzing circulating tumor DNA (ctDNA) in patients with solid tumors suggest the potential to accurately predict and detect relapse, enabling treatment strategies that may improve clinical outcomes. Over the past decade, assays for ctDNA detection in plasma samples have steadily increased in sensitivity and specificity. These are applied for the detection of residual disease after treatment and for earlier detection of recurrence. Novel clinical trials are now assessing how assays for "residual disease and recurrence" (RDR) may influence current treatment paradigms and potentially change the landscape of risk classification for cancer recurrence. In this review, we appraise the progress of RDR detection using ctDNA and consider the emerging role of liquid biopsy in the monitoring and management of solid tumors.

PURPOSE Precision oncology has transformed the management of advanced cancers through implementation of advanced molecular profiling technologies to identify increasingly defined subsets of patients and match them to appropriate therapy. We report outcomes of a prospective molecular profiling study in a high-volume Asian tertiary cancer center. PATIENTS AND METHODS Patients with advanced cancer were enrolled onto a prospective protocol for genomic profiling, the Individualized Molecular Profiling for Allocation to Clinical Trials Singapore study, at the National Cancer Center Singapore. Primary objective was to identify molecular biomarkers in patient's tumors for allocation to clinical trials. The study commenced in February 2012 and is ongoing, with the results of all patients who underwent multiplex next-generation sequencing (NGS) testing until December 2018 presented here. The results were discussed at a molecular tumor board where recommendations for allocation to biomarker-directed trials or targeted therapies were made. RESULTS One thousand fifteen patients were enrolled with a median age of 58 years (range 20-83 years). Most common tumor types were lung adenocarcinoma (26%), colorectal cancer (15%), and breast cancer (12%). A total of 1,064 NGS assays were performed, on fresh tumor tissue for 369 (35%) and archival tumor tissue for 687 (65%) assays. TP53 (39%) alterations were most common, followed by EGFR (21%), KRAS (14%), and PIK3CA (10%). Of 405 NGS assays with potentially actionable alterations, 111 (27%) were allocated to a clinical trial after molecular tumor board and 20 (4.9%) were enrolled on a molecularly matched clinical trial. Gene fusions were detected in 23 of 311 (7%) patients tested, including rare fusions in new tumor types and known fusions in rare tumors. CONCLUSION Individualized Molecular Profiling for Allocation to Clinical Trials Singapore demonstrates the feasibility of a prospective broad molecular profiling program in an Asian tertiary cancer center, with the ability to develop and adapt to a dynamic landscape of precision oncology.

Background: The Phase III MONALEESA (ML)-2, -3, and -7 trials showed significant improvement in progression-free survival (PFS) and overall survival (OS) with ribociclib (RIB) + endocrine therapy (ET) over placebo (PBO) + ET in patients (pts) with HR+/HER2− advanced breast cancer (ABC); improvement in OS with cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) has been observed in some, but not all clinical trials. Gene expression analyses for each separate ML study were reported previously. Given the differences in CDK4 vs CDK6 inhibition between RIB and other CDK4/6i, we evaluated the association between cell cycle (CC)–related genes and outcomes based on pooled analysis of gene expression using tumor samples from the ML-2, -3, and -7 trials. Methods: Gene expression data were generated from pre-treatment archival tumor samples (primary, 73%; metastatic, 27%) with a customized NanoString nCounter panel (781 genes) including genes involved in CC, other signaling pathways, and breast cancer biology. Samples were pooled from 1139 pre- and postmenopausal pts with HR+/HER2− ABC across the 3 ML studies, which included pts on first- and second-line therapy. Data were categorized into training (80%) and test (20%) datasets. The training dataset was used to analyze each gene (modeled continuously) individually for an association with PFS, and genes with a gene × treatment (tx) interaction P value Results: This report focused on CC-related genes and signatures. Gene expression levels of CDKN2B and the expression ratio of CCND1/CDKN2A showed a predictive relationship with benefit from RIB in both training and test sets (Table). PFS benefit with RIB was consistent regardless of the CDK4/CDK6 expression ratio or level of expression of CCNE1, CDK2, RB1, combined CC-related genes, E2F gene signatures, RB gene signature, combined DNA-replication genes, or combined proliferation-related genes. A machine learning approach identified a clinico-genomic signature that was prognostic for PFS benefit with RIB. Selected variables included gene expression levels of FXBO5, PGR, RBBP8, and STC2 and several clinical features (tx arm, de novo disease, prior ET, and visceral disease). Pts with a low signature score had a longer mPFS vs pts with a high signature score, in the RIB (HR, 0.37; 95% CI, 0.22-0.62) and PBO (HR, 0.30; 95% CI, 0.15-0.59) arms. Conclusion: In the largest pooled analysis of the association of gene expression profile data with CDK4/6i tx response in pts with HR+/HER2− ABC, the PFS benefit with RIB + ET over ET alone was consistent irrespective of expression levels of most CC genes. Variation in magnitude of RIB benefit was observed, depending on CDKN2B expression levels, CCND1/CDKN2A expression ratio, and machine learning–derived signature scores. The clinico-genomic CDK4/6i signature requires validation in additional datasets. Table 1: Progression-Free Survival by Gene Expression Subgroup Citation Format: Aditya Bardia, Faye Su, Nadia Solovieff, Fabrice Andre, Carlos Arteaga, Patrick Neven, Yoon-Sim Yap, Yen-Shen Lu, Stephen K. Chia, Dennis Slamon, Seock-Ah Im, Arunava Chakravartty, Agnes Lteif, Tetiana Taran, Debu Tripathy. Pooled gene expression analysis and association with treatment response in patients with HR+/HER2− advanced breast cancer in the MONALEESA-2, -3, and -7 trials [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD17-08.

Breast cancer (BC) among Asians accounts for ~ 40% of the global BC burden. Differences in BC risk, presentation, tumor biology, and response to treatment exist between Asian and non-Asian patients; however, Asian patients are often under-represented in clinical trials. This narrative review summarizes the efficacy and safety of pharmacological therapies for BC in Asian populations, with a focus on outcomes in Asian versus non-Asian patients treated with chemotherapy, hormone therapy, anti-human epidermal growth factor receptor-2 targeted therapies, cyclin-dependent kinase 4/6 (CDK4/6) inhibitors, mammalian target of rapamycin inhibitors, bone-targeted therapies, poly-ADP ribose polymerase, phosphoinositide 3-kinase, and checkpoint inhibitors. While most therapies have demonstrated comparable efficacy and safety in Asian and non-Asian patients with BC, differences that are largely attributed to pharmacogenetic variations between populations exist. Pharmacogenetic differences may contribute to a reduced clinical benefit of tamoxifen, whereas improved clinical outcomes have been reported with tyrosine kinase inhibitors and CDK4/6 inhibitors in Asian versus non-Asian patients with BC. In particular, Asian patients have an increased incidence of hematological toxicities, including neutropenia, although adverse events can be effectively managed using dose adjustments. Recent trials with CDK4/6 inhibitors have increased efforts to include Asians within study subsets. Future clinical trials enrolling higher numbers of Asian patients, and an increased understanding of differences in patient and tumor genetics between Asians and non-Asians, have the potential to incrementally improve the management of BC in Asian patients.

Background: Genetic alterations that contribute to resistance to therapy may be acquired during treatment (tx) for hormone receptor−positive/human epidermal growth factor receptor−negative (HR+/HER2−) advanced breast cancer (ABC). A previous pooled analysis of circulating tumor DNA (ctDNA) in MONALEESA (ML)-2, -3, and -7 identified potential predictive biomarkers for response and resistance to ribociclib (RIB) at baseline (BL). Here, we describe an analysis of paired BL and end of treatment (EOT) samples from ML-2, -3, and -7 to identify acquired mechanisms that may impact resistance to RIB + endocrine therapy (ET) vs placebo (PBO) + ET. Methods: ML-2 (NCT01958021), ML-3 (NCT02422615), and ML-7 (NCT02278120) evaluated efficacy and safety of RIB + ET vs PBO + ET in pre- and postmenopausal patients (pts) with HR+/HER2− ABC treated in first-line (1L) and second-line (2L) settings. Plasma samples were collected at cycle 1 day 1 (C1D1; prior to first therapy exposure) and at EOT (± 28 days of recorded progression). ctDNA was sequenced using a targeted next-generation sequencing panel of ≈550 genes. Genes with an alteration frequency of >5% at EOT, regardless of their frequency at BL, were included. Tumor mutational burden (TMB) was assessed by tx arm; a TMB cutoff of 10 mutations/MB was used to categorize pts as TMB high vs low. To assess differences in the presence of alterations, a McNemar test was performed on paired samples and adjusted (adj) for multiple testing using the false discovery rate (FDR). A Bayesian mixed effects model was used to account for ctDNA fraction and trial and to test for tx-specific resistance by including a tx × visit interaction term. Results: A total of 905 paired samples from ML-2, -3, and -7 were included in this analysis, 441 and 464 samples from pts treated with RIB + ET and PBO + ET, respectively. Overall, 17 genes had an alteration frequency of >5% at EOT. The ctDNA fraction was higher at EOT vs C1D1 in both the RIB (P=.037) and PBO (P=.033) arms. The frequency of alterations in RB1 (10.4% vs 2.0%), ATM (11.3% vs 8.4%), FAT1 (4.8% vs 3.0%), and FAT3 (5.0% vs 2.5%) was higher at EOT vs C1D1 in the RIB arm (FDR-adj P10) at EOT increased from 1.1% to 5.7% in the RIB arm and from 1.7% to 3% in the PBO arm. After accounting for ctDNA fraction and trial, a larger numerical increase in TMB was observed for RIB (odds ratio [OR], 9.0; 95% CI, 2.9-32.7) vs PBO (OR, 2.1; 95% CI, 0.7-6.5); however, the model did not support a differential tx effect. Conclusions: This comprehensive analysis of pooled samples from ML-2, -3, and -7 identified acquired gene alterations in pts with HR+/HER2− ABC treated with 1L or 2L RIB + ET or PBO + ET. The frequency of several genes known to contribute to resistance (ESR1, RB1, ATM, FAT1, and FAT3) was higher at EOT vs C1D1 in pts treated with RIB + ET, while ESR1 and GATA3 alterations were higher at EOT vs C1D1 in pts treated with PBO + ET. This paired dataset of BL and EOT samples from pts with HR+/HER2− ABC treated with a CDK4/6 inhibitor and ET is the largest to date and could be used to validate and confirm acquired resistance mechanisms with low alteration frequency. Citation Format: Fabrice Andre, Nadia Solovieff, Faye Su, Aditya Bardia, Patrick Neven, Yoon-Sim Yap, Debu Tripathy, Yen-Shen Lu, Dennis Slamon, Stephen K. Chia, Mukta Joshi, Arunava Chakravartty, Agnes Lteif, Tetiana Taran, Carlos Arteaga. Identification of mechanisms of acquired resistance to ribociclib plus endocrine therapy using baseline and end-of-treatment circulating tumor DNA samples in the MONALEESA-2, -3, and -7 trials [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-02-14.

Acquired multidrug resistance in tumors is a big challenge in cancer therapy. As an important physical stimulus in the tumor microenvironment, elevated interstitial fluid pressure has been reported to inhibit drug delivery and promote metastasis in solid tumors. However, the direct influence of this fluid pressure on anticancer drug resistance remains unclear. Here, we develop a pressurized in vitro circulating tumor cell (CTC) culture platform for anticancer drug screening. By using human breast cancer cell line MCF-7 and MDA-MB-231, we find that doxorubicin resistance can be increased by up to 2.5 times under 30 mmHg culture condition, through ABCC1 overexpression that reduces intracellular doxorubicin concentration. A similar chemoresistance change is also observed in clinical metastatic circulating tumor cells samples. These findings provide a new insight into the chemoresistance mechanism of metastatic human breast cancer cells and elucidate the significance of abnormal hydrostatic pressure in cancer progression.

Breast cancer is the most frequent cancer amongst women worldwide including in Asia where the incidence rate is rapidly increasing. Even with treatment, around 30% of patients with early breast cancer progress to metastatic disease, with hormone receptor positive (HR+) and human epidermal growth factor receptor 2 negative (HER2-) breast cancer the most common phenotype. First-line endocrine therapy targeting the estrogen receptor signaling pathway provides a median progression-free survival or time to progression of 6-15 months in HR + HER2- metastatic breast cancer. Recently, cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors, combined with endocrine therapy, have achieved more than two years median progression-free survival in HR + HER2- metastatic breast cancer. However, the characteristics of the Asian breast cancer population differ from those of Western populations and need to be considered when selecting a suitable treatment. Breast cancer is diagnosed at a younger age in Asian populations and late stage at presentation is generally more common in low-/middle-income countries than high-income countries. Consequently, the proportion of premenopausal women with metastatic breast cancer is higher in Asian compared with Western populations. While CDK4/6 inhibitors have been approved in the USA (FDA) since 2015, experience with them in Asia is more limited. We review the experience with the CDK4/6 inhibitor palbociclib in Asian patients with HR + HER2- metastatic breast cancer and provide guidance on the use of palbociclib in these patients.

BACKGROUND Invasive lobular carcinomas (ILC) form 5%-10% of breast cancer and rarely show overexpression of human epidermal growth factor receptor 2 (HER2). AIM To describe the prevalence and prognostic factors of HER2 positive (HER2+) ILC in an Asian population. METHODS A retrospective review of patients with ILC seen between January 1985 and March 2018 at various SingHealth medical institutions was conducted. Demographic and clinical data were collected from medical records. We examined clinicopathological characteristics and survival in relation to HER2 status. RESULTS A total of 864 patients were included. Prevalence of HER2 positivity was 10.1% (87 patients). Compared with HER2 negative (HER2-) ILC, HER2+ ILC was associated with a higher proportion of estrogen receptor negative (24.4% vs 5.9%, P < 0.001), progesterone receptor negative (PR-) (40.2% vs 24%, P = 0.002) and grade 3 tumours (Grade 3, 29.0% vs 10.2%, P < 0.001). Overall survival rate was poorer in patients with HER2+ compared to HER2- ILC (56.7% vs 72.9% alive at 10 years; hazard ratio 1.87, 95% confidence interval: 1.21-2.90, P = 0.004). Based on multivariate analysis, negative prognostic factors for overall survival included HER2 positivity, PR negativity, older age, Indian ethnicity and higher tumour stage. CONCLUSION Prevalence of HER2+ ILC was 10.1%. HER2+ ILC was more likely to have poorer prognostic features such as estrogen receptor negative, PR- and higher tumour grade, and have a poorer survival.

Background: LSZ102 is an orally bioavailable selective estrogen receptor degrader (SERD) that inhibits estrogen receptor (ER) mediated gene transcription, induces receptor degradation, and blocks ER-dependent cell growth in preclinical models. This first-in-human study of LSZ102 is evaluating LSZ102 as a single agent (SA) and in combination with the CDK4/6 inhibitor ribociclib or the PI3K inhibitor alpelisib (BYL719) in patients (pts) with locally advanced/metastatic ER-positive (ER+) breast cancer (BC). Here, we present the immunohistochemistry (IHC) and circulating tumor DNA (ctDNA) data obtained from a subset of pts treated with either LSZ102 SA or the combination of LSZ102 and ribociclib. Methods: ER IHC was performed with an antirabbit antibody (clone SP1) on FFPE samples collected at baseline and cycle 1 day 15 (C1D15), and the ER value was reported using the H-score method. A Novartis exploratory PanCancer next-generation sequencing ~600 gene panel for cell-free DNA (cfDNA) was used on plasma samples collected from pts treated with SA or the combination at baseline, on treatment (C1D1, C2D1/C3D1, C5D1, CXD1) at radiological assessments and at the end of treatment (EOT). Results: One hundred fifty-three pts with MBC (median number of prior lines of therapy in metastatic setting = 4; range, 0-10) were treated with LSZ102 SA or the combination of LSZ102 and ribociclib (data cutoff, November 30, 2018). ER protein levels, assessed by IHC H-score, are downregulated in about 75% of C1D15 samples in both SA and combination-treated pts. In this cohort of heavily pretreated pts, cfDNA sequencing was performed on approximately 400 samples from 135 pts, and the genomic landscape is described both at baseline and EOT for pts with detectable ctDNA (~77% of pts). At baseline, approximately 40% of pts had mutations in the ESR1 ligand-binding domain (LBD), and approximately 40% of pts had PIK3CA activating mutations. LBD ESR1 mutations were mainly subclonal with several pts harboring multiple mutations at baseline. The frequency of ESR1 Y537S mutation was no higher in EOT samples after LSZ102 treatment compared with baseline. Moreover, the tumor reduction of target lesions > 30% was observed in pts harboring different baseline ESR1 mutations, including Y537S, treated with either SA or the combination. Furthermore, the longitudinal cfDNA analysis showed a consistent reduction of the overall circulating tumor fraction (ctDNA fraction), from baseline for the majority of patients who achieved either partial response or stable disease with either SA or the combination. Conclusions: Consistent with being a SERD, LSZ102 treatment leads to the degradation of ER in tumor biopsies. The addition of ribociclib does not alter LSZ102-induced ER downregulation. The most common genetic alterations found in cfDNA collected from enrolled ER+ MBC patients before the study treatment were ESR1 and PIK3CA mutations. Importantly, the antitumor activity was observed in pts harboring a variety of ESR1 LBD mutations. Furthermore, enrichment of ESR1 Y537S mutations was not observed after LSZ102 treatment. Finally, the on-treatment longitudinal assessment of cfDNA measuring ctDNA fraction and mutation dynamics is maturing as a useful tool for monitoring the treatment efficacy. Citation Format: Komal Jhaveri, Dejan Juric, Sara Cresta, Yoon-Sim Yap, Francois P. Duhoux, Catherine Terret, Rachel Layman, Alejandro Balbin, Qing Sheng, Serena Liao, Adam Crystal, Giuseppe Curigliano. Tumor ER protein modulation, molecular characterization and monitoring of cfDNA in phase 1 study of LSZ102 and LSZ102 + ribociclib in patients with ER+ MBC [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-10-07.

The identification and characterization of circulating tumor cells (CTCs) are important for gaining insights into the biology of metastatic cancers, monitoring disease progression, and medical management of the disease. The limiting factor in the enrichment of purified CTC populations is their sparse availability, heterogeneity, and altered phenotypes relative to the primary tumor. Intensive research both at the technical and molecular fronts led to the development of assays that ease CTC detection and identification from peripheral blood. Most CTC detection methods based on single-cell RNA sequencing (scRNA-seq) use a mix of size selection, marker-based white blood cell (WBC) depletion, and antibodies targeting tumor-associated antigens. However, the majority of these methods either miss out on atypical CTCs or suffer from WBC contamination. We present unCTC, an R package for unbiased identification and characterization of CTCs from single-cell transcriptomic data. unCTC features many standard and novel computational and statistical modules for various analyses. These include a novel method of scRNA-seq clustering, named deep dictionary learning usingk-means clustering cost (DDLK), expression-based copy number variation (CNV) inference, and combinatorial, marker-based verification of the malignant phenotypes. DDLK enables robust segregation of CTCs and WBCs in the pathway space, as opposed to the gene expression space. We validated the utility of unCTC on scRNA-seq profiles of breast CTCs from six patients, captured and profiled using an integrated ClearCell FX and Polaris workflow that works by the principles of size-based separation of CTCs and marker-based WBC depletion.

Precision medicine is playing an increasingly important role in cancer management and treatment. Specifically in the field of oncology, circulating tumor cells (CTCs) hold significant promise in enabling non-invasive prognostication and near real-time monitoring to individualize treatments. In this study, we present strong associations between CTC subtype counts with treatment response and tumor staging in lung, nasopharyngeal and breast cancers. Longitudinal analysis of CTC count changes over short-time windows further reveals the ability to predict treatment response close to real-time. Our findings demonstrate the suitability of CTCs as a definitive blood-based metric for continuous treatment monitoring. Robust processing of high-throughput image data, explainable classification of CTC subtypes and accurate quantification were achieved using an in-house image analysis system ‘CTC-Quant’, which showed excellent agreement with expert opinion upon extensive validation.

Background HER2-low breast cancer (BC) is currently an area of active interest. This study evaluated the impact of low expression of HER2 on survival outcomes in HER2-negative non-metastatic breast cancer (BC). Methods Patients with HER2-negative non-metastatic BC from 6 centres within the Asian Breast Cancer Cooperative Group (ABCCG) (n = 28,280) were analysed. HER2-low was defined as immunohistochemistry (IHC) 1+ or 2+ and in situ hybridization non-amplified (ISH−) and HER2-zero as IHC 0. Relapse-free survival (RFS) and overall survival (OS) by hormone receptor status and HER2 IHC 0, 1+ and 2+ ISH− status were the main outcomes. A combined TCGA-BRCA and METABRIC cohort (n = 1967) was also analysed to explore the association between HER2 expression, ERBB2 copy number variation (CNV) status and RFS. Results ABCCG cohort median follow-up was 6.6 years; there were 12,260 (43.4%) HER2-low BC and 16,020 (56.6%) HER2-zero BC. The outcomes were better in HER2-low BC than in HER2-zero BC (RFS: centre-adjusted hazard ratio (HR) 0.88, 95% CI 0.82–0.93, P < 0.001; OS: centre-adjusted HR 0.82, 95% CI 0.76–0.89, P < 0.001). On multivariable analysis, HER2-low status was prognostic (RFS: HR 0.90, 95% CI 0.85–0.96, P = 0.002; OS: HR 0.86, 95% CI 0.79–0.93, P < 0.001). These differences remained significant in hormone receptor-positive tumours and for OS in hormone receptor-negative tumours. Superior outcomes were observed for HER2 IHC1+ BC versus HER2-zero BC (RFS: HR 0.89, 95% CI 0.83–0.96, P = 0.001; OS: HR 0.85, 95% CI 0.78–0.93, P = 0.001). No significant differences were seen between HER2 IHC2+ ISH− and HER2-zero BCs. In the TCGA-BRCA and METABRIC cohorts, ERBB2 CNV status was an independent RFS prognostic factor (neutral versus non-neutral HR 0.71, 95% CI 0.59–0.86, P < 0.001); no differences in RFS by ERBB2 mRNA expression levels were found. Conclusions HER2-low BC had a superior prognosis compared to HER2-zero BC in the non-metastatic setting, though absolute differences were modest and driven by HER2 IHC 1+ BC. ERBB2 CNV merits further investigation in HER2-negative BC.

The identification and characterization of circulating tumor cells (CTCs) are important for gaining insights into the biology of metastatic cancers, monitoring disease progression, and medical management of the disease. The limiting factor that hinders enrichment of purified CTC populations is their sparse availability, heterogeneity, and altered phenotypic traits relative to the tumor of origin. Intensive research both at the technical and molecular fronts led to the development of assays that ease CTC detection and identification from the peripheral blood. Most CTC detection methods use a mix of size selection, immune marker based white blood cells (WBC) depletion, and positive enrichment antibodies targeting tumor-associated antigens. However, the majority of these methods either miss out on atypical CTCs or suffer from WBC contamination. Single-cell RNA sequencing (scRNA-Seq) of CTCs provides a wealth of information about their tumors of origin as well as their fate and is a potent method of enabling unbiased identification of CTCs. We present unCTC, an R package for unbiased identification and characterization of CTCs from single-cell transcriptomic data. unCTC features many standard and novel computational and statistical modules for various analysis tasks. These include a novel method of scRNA-Seq clustering, named Deep Dictionary Learning using K-means clustering cost (DDLK), expression based copy number variation (CNV) inference, and combinatorial, marker-based verification of the malignant phenotypes. DDLK enables robust segregation of CTCs and WBCs in the pathway space, as opposed to the gene expression space. We validated the utility of unCTC on scRNA-Seq profiles of breast CTCs from six patients, captured and profiled using an integrated ClearCell® FX and PolarisTM workflow that works by the principles of size-based separation of CTCs and marker based WBC depletion.

IntroductionCirculating tumor cells (CTCs) and cell-free tumor DNA (ctDNA) are tumor components present in circulation. Due to the limited access to both CTC enrichment platforms and ctDNA sequencing in most laboratories, they are rarely analyzed together.MethodsConcurrent isolation of ctDNA and single CTCs were isolated from lung cancer and breast cancer patients using the combination of size-based and CD45-negative selection method via DropCell platform. We performed targeted amplicon sequencing to evaluate the genomic heterogeneity of CTCs and ctDNA in lung cancer and breast cancer patients.ResultsHigher degrees of genomic heterogeneity were observed in CTCs as compared to ctDNA. Several shared alterations present in CTCs and ctDNA were undetected in the primary tumor, highlighting the intra-tumoral heterogeneity of tumor components that were shed into systemic circulation. Accordingly, CTCs and ctDNA displayed higher degree of concordance with the metastatic tumor than the primary tumor. The alterations detected in circulation correlated with worse survival outcome for both lung and breast cancer patients emphasizing the impact of the metastatic phenotype. Notably, evolving genetic signatures were detected in the CTCs and ctDNA samples during the course of treatment and disease progression.ConclusionsA standardized sample processing and data analysis workflow for concurrent analysis of CTCs and ctDNA successfully dissected the heterogeneity of metastatic tumor in circulation as well as the progressive genomic changes that may potentially guide the selection of appropriate therapy against evolving tumor clonality.

Background: The combination of ribociclib (an oral CDK4/6 inhibitor) and ET improved survival outcomes in patients (pts) with ER+ ABC in comparison to single-agent ET. In preclinical models, LSZ102 (an experimental oral SERD) demonstrated synergistic activity with ribociclib. This phase 1/1b, open-label study evaluates single-agent LSZ102 (Arm A) and LSZ102 in combination with ribociclib (Arm B) or alpelisib (Arm C) in pts with ER+ ABC who had progressed after ET. Here we present preliminary data from dose escalation of Arm B. Methods: Dose-escalation evaluated daily (QD) LSZ102 at different doses plus ribociclib starting at 300 mg QD either in a 3-week on/1-week (3w/1w) off or in continuous regimen. Pts (aged ≥18 years; ECOG PS 0-1) with histologically confirmed ER+ ABC and progression after ET were enrolled. Prior fulvestrant and/or CDK4/6 inhibitor therapy were permitted. The primary objective was to characterize the safety and tolerability of LSZ102 and ribociclib in combination and identify a recommended dose for expansion (RDE). Secondary objectives included preliminary antitumor activity and characterization of pharmacokinetics. Results: As of 30-Nov-2018, 76 pts were enrolled. The median age of pts was 59 years, 78% (n=59) were Caucasian, 75% (n=57) had an ECOG PS of 0, 63% (n=48) had received prior fulvestrant, and 43% (n=33) a prior CDK4/6 inhibitor; the median number of prior lines of therapy (metastatic setting) was 4 (range 0-10). Pts received LSZ102 QD in combination with ribociclib QD either in a 3w/1w (n=42) or continuous (n=24) regimen, fasted, fed or without regard to food. LSZ102 twice daily (BID) was also explored with a ribociclib BID continuous regimen (n=10). Doses of LSZ102 ranged from 200-600 mg QD and 200-300 mg BID. Doses of ribociclib ranged from 200-600 mg and 200-400 mg in the 3w/1w and continuous regimens, respectively. At data cut-off, 47 pts had discontinued treatment, 42 due to disease progression. Three dose-limiting toxicities were reported: decreased appetite (1 pt) and febrile neutropenia and sepsis (1 pt), all in the 3w/1w regimen. The most common treatment-related adverse events (AEs) were nausea (48.7%), diarrhea (31.6%), fatigue (26.3%), and neutropenia (25.0%). The most common treatment-related grade 3 or 4 AE was neutropenia (10.5%). Four pts (5.3%) required dose reduction due to an AE. Median PFS was 6.0 months. Of 71 evaluable pts, 11% (n=8) had a PR, 39% (n=28) had a best overall response of SD and 16% (n=11) had non-CR/non-PD. ORR, DCR and CBR ≥6 months (includes non-CR/non-PD) were 11% (n=8), 66% (n=47) and 21% (n=15), respectively. The RDE is 450 mg QD LSZ102 with 400 mg QD ribociclib for both ribociclib regimens. Preliminary PK showed the exposure of LSZ102 and ribociclib in combination at the RDE were largely comparable with exposure of the corresponding single agents. Conclusion: The combination of LSZ102 and ribociclib was well-tolerated and demonstrated antitumor activity in heavily pre-treated pts with ER+ ABC many of whom had progressed after fulvestrant and/or CDK4/6 inhibitor therapy. Citation Format: Komal Jhaveri, Dejan Juric, Sara Cresta, Yoon-Sim Yap, Francois P Duhoux, Catherine Terret, Rachel Layman, Nicole Kundamal, Serena Liao, Yan Ji, Adam Crystal, Giuseppe Curigliano. A phase 1/1b study of LSZ102, an oral selective estrogen receptor degrader (SERD), in combination with ribociclib in patients with estrogen receptor-positive (ER+) advanced breast cancer (ABC) who had progressed after endocrine therapy (ET) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD7-09.

Purpose BioPATH is a non-interventional study evaluating the relationship of molecular biomarkers (PTEN deletion/downregulation, PIK3CA mutation, truncated HER2 receptor [p95HER2], and tumor HER2 mRNA levels) to treatment responses in Asian patients with HER2+ advanced breast cancer treated with lapatinib and other HER2-targeted agents. Materials and methods Female Asian HER2+ breast cancer patients (n=154) who were candidates for lapatinib-based treatment following metastasis and having an available primary tumor biopsy specimen were included. The primary endpoint was progression-free survival (PFS). Secondary endpoints were response rate, overall survival on lapatinib, correlation between biomarker status and PFS for any previous trastuzumab-based treatment, and conversion/conservation rates of the biomarker status between tissue samples collected at primary diagnosis and at recurrence/metastasis. Potential relationships between tumor mRNA levels of HER2 and response to lapatinib-based therapy were also explored. Results p95HER2, PTEN deletion/downregulation, and PIK3CA mutation did not demonstrate any significant co-occurrence pattern and were not predictive of clinical outcomes on either lapatinib-based treatment or any previous trastuzumab-based therapy in the metastatic setting. Proportions of tumors positive for p95HER2 expression, PIK3CA mutation, and PTEN deletion/down-regulation at primary diagnosis were 32%, 31.2%, and 56.2%, respectively. Despite limited availability of paired samples, biomarker status patterns were conserved in most samples. HER2 mRNA levels were not predictive of PFS on lapatinib. Conclusion The prevalence of p95HER2 expression, PIK3CA mutation, and PTEN deletion/downregulation at primary diagnosis were similar to previous reports. Importantly, no difference was observed in clinical outcome based on the status of these biomarkers, consistent with reports from other studies.

Breast cancer in young Asian women has distinctive clinicopathological characteristics; hence, we question the universal generalizability of treatment recommendations based on data from predominantly non-Asian postmenopausal women. The Asian Breast Cancer Cooperative Group (ABCCG) reviewed current ESO-ESMO and St. Gallen recommendations for treating hormone receptor positive/human epidermal growth factor receptor 2 negative (HR+/HER2−) breast cancer in premenopausal women. Points disputed by ≥ 3/12 members were discussed, and statements on contentious issues formulated for anonymous voting; consensus required a ≥ 75% majority. The ABCCG contends that: (1) Trials in premenopausal women are not only necessary, but also worthwhile if performed separately from others that also enroll postmenopausal participants. (2) Not all premenopausal women with HR+ early breast cancer need adjuvant ovarian function suppression (OFS). (3) Certain clinical factors might influence decision-making about prescribing OFS. (4) For early HR+/HER2− breast cancer in premenopausal patients with OFS, tamoxifen is preferred for intermediate-risk cases; for high risk, near-consensus supported aromatase inhibitor, despite no clear overall survival benefit versus tamoxifen. (5) Oncotype DX Breast Recurrence Score® has different treatment implications in patients aged ≤ 50 versus > 50 years. (6) High-risk patients (if premenopausal after chemotherapy) should receive adjuvant chemotherapy and OFS plus aromatase inhibitor. (7) For patients with advanced disease receiving OFS on a backbone of tamoxifen, gonadotrophin-releasing hormone agonists may be given 12-weekly. (8) For premenopausal women who decline OFS or oophorectomy, tamoxifen alone is still an option but is considered less effective; other monotherapies are also less effective than OFS plus such treatments. Premenopausal Asian women with breast cancer have unique disease characteristics and may benefit from treatment that differs somewhat from international guidelines. Given the great diversity of patients and clinical settings worldwide, the ABCCG advocates evidence-based yet flexible and individualized use of all potential options to improve breast cancer outcomes.

Aim: To evaluate the efficacy and safety of neratinib as extended adjuvant therapy in patients from Asia based on exploratory analyses of the Phase III ExteNET trial. Patients & methods: A total of 2840 women with early stage HER2-positive breast cancer were randomly assigned to neratinib 240 mg/day or placebo for 1 year after trastuzumab-based adjuvant therapy. Results: A total of 341 patients were from Asia (neratinib, n = 165; placebo, n = 176). 2-year invasive disease-free survival rates were 92.8 and 90.8% with neratinib and placebo, respectively (HR: 0.70; 95% CI: 0.31–1.55), and 5-year rates were 91.9 and 87.2%, respectively (HR: 0.57; 95% CI: 0.27–1.13). Diarrhea was the most common adverse event with neratinib. Conclusion: Extended adjuvant therapy with neratinib reduces disease recurrences in Asian women with HER2-positive breast cancer. Trial registration: Clinicaltrials.gov NCT00878709.

Purpose: Neratinib, an irreversible pan-HER tyrosine kinase inhibitor, has demonstrated systemic efficacy and intracranial activity in various stages of HER2+ breast cancer. NALA was a phase III randomized trial that assessed the efficacy and safety of neratinib + capecitabine (N+C) against lapatinib + capecitabine (L+C) in HER2+ metastatic breast cancer (mBC) patients who had received ≥2 HER2-directed regimens. Descriptive analysis results of the Asian subgroup in the NALA study are reported herein.Methods: 621 centrally-assessed HER2+ mBC patients were enrolled, 202 of whom were Asian. Those with stable, asymptomatic brain metastases (BM) were eligible for study entry. Patients were randomized 1:1 to N (240mg qd) + C (750mg/m2 bid, day 1-14) with loperamide prophylaxis, or to L (1250mg qd) + C (1000mg/m2 bid, day 1-14) in 21-day cycles. Co-primary endpoints were centrally-assessed progression free survival (PFS) and overall survival (OS). Secondary endpoints included time to intervention for central nervous system (CNS) disease, objective response rate, duration of response (DoR), clinical benefit rate, and safety.Results: 104 and 98 Asian patients were randomly assigned to receive N+C or L+C, respectively. Median PFS of N+C and L+C was 7.0 and 5.4 months (P=0.0014), respectively. Overall cumulative incidence of intervention for CNS disease was lower with N+C (27.9 versus 33.8%; P=0.039). Both median OS (23.8 versus 18.7 months; P=0.185) and DoR (11.1 versus 4.2 months; PConclusion: Consistent with the efficacy profile observed in the overall study population, Asian patients with HER2+ mBC, who had received ≥2 HER2-directed regimens, may also benefit from N+C. No new safety signals were noted. Clinical Trial Registration: NCT01808573

Profiling of circulating tumor DNA (ctDNA) may offer a non-invasive approach to monitor disease progression. Here, we develop a quantitative method, exploiting local tissue-specific cell-free DNA (cfDNA) degradation patterns, that accurately estimates ctDNA burden independent of genomic aberrations. Nucleosome-dependent cfDNA degradation at promoters and first exon-intron junctions is strongly associated with differential transcriptional activity in tumors and blood. A quantitative model, based on just 6 regulatory regions, could accurately predict ctDNA levels in colorectal cancer patients. Strikingly, a model restricted to blood-specific regulatory regions could predict ctDNA levels across both colorectal and breast cancer patients. Using compact targeted sequencing (, Circulating tumour DNA (ctDNA) represents a non-invasive option to monitor cancer progression. Here, the authors perform deep sequencing of plasma cell-free DNA, and find that nucleosome-dependent cfDNA degradation at 6 specific regulatory regions is predictive of ctDNA burden.

Purpose Neratinib, an irreversible pan-HER tyrosine kinase inhibitor, has demonstrated systemic efficacy and intracranial activity in various stages of HER2+breast cancer. NALA was a phase III randomized trial that assessed the efficacy and safety of neratinib+capecitabine (N+C) against lapatinib+capecitabine (L+C) in HER2+ metastatic breast cancer (mBC) patients who had received ≥ 2 HER2-directed regimens. Descriptive analysis results of the Asian subgroup in the NALA study are reported herein. Methods 621 centrally assessed HER2+ mBC patients were enrolled, 202 of whom were Asian. Those with stable, asymptomatic brain metastases (BM) were eligible for study entry. Patients were randomized 1:1 to N (240 mg qd) + C (750 mg/m2 bid, day 1–14) with loperamide prophylaxis or to L (1250 mg qd) + C (1000 mg/m2 bid, day 1–14) in 21-day cycles. Co-primary endpoints were centrally assessed progression-free survival (PFS) and overall survival (OS). Secondary endpoints included time to intervention for central nervous system (CNS) disease, objective response rate, duration of response (DoR), clinical benefit rate, and safety. Results 104 and 98 Asian patients were randomly assigned to receive N+C or L+C, respectively. Median PFS of N+C and L+C was 7.0 and 5.4 months (P = 0.0011), respectively. Overall cumulative incidence of intervention for CNS disease was lower with N+C (27.9 versus 33.8%; P = 0.039). Both median OS (23.8 versus 18.7 months; P = 0.185) and DoR (11.1 versus 4.2 months; P Conclusion Consistent with the efficacy profile observed in the overall study population, Asian patients with HER2+ mBC, who had received ≥ 2 HER2-directed regimens, may also benefit from N+C. No new safety signals were noted. Clinical trial registration NCT01808573

We collated publicly available single-cell expression profiles of circulating tumor cells (CTCs) and showed that CTCs across cancers lie on a near-perfect continuum of epithelial to mesenchymal (EMT) transition. Integrative analysis of CTC transcriptomes also highlighted the inverse gene expression pattern between PD-L1 and MHC, which is implicated in cancer immunotherapy. We used the CTCs expression profiles in tandem with publicly available peripheral blood mononuclear cell (PBMC) transcriptomes to train a classifier that accurately recognizes CTCs of diverse phenotype. Further, we used this classifier to validate circulating breast tumor cells captured using a newly developed microfluidic system for label-free enrichment of CTCs.

Description, Fatty acid oxidation is a metabolic gateway that regulates cellular plasticity and supports metastasis in breast cancer., Cell state transitions control the functional behavior of cancer cells. Epithelial-to-mesenchymal transition (EMT) confers cancer stem cell-like properties, enhanced tumorigenicity and drug resistance to tumor cells, while mesenchymal-epithelial transition (MET) reverses these phenotypes. Using high-throughput chemical library screens, retinoids are found to be potent promoters of MET that inhibit tumorigenicity in basal-like breast cancer. Cell state transitions are defined by reprogramming of lipid metabolism. Retinoids bind cognate nuclear receptors, which target lipid metabolism genes, thereby redirecting fatty acids for β-oxidation in the mesenchymal cell state towards lipid storage in the epithelial cell state. Disruptions of key metabolic enzymes mediating this flux inhibit MET. Conversely, perturbations to fatty acid oxidation (FAO) rechannel fatty acid flux and promote a more epithelial cell phenotype, blocking EMT-driven breast cancer metastasis in animal models. FAO impinges on the epigenetic control of EMT through acetyl-CoA-dependent regulation of histone acetylation on EMT genes, thus determining cell states.

Introduction: We conducted a randomized controlled trial evaluating the efficacy and tolerability of cryotherapy in preventing chemotherapy-induced peripheral neuropathy (CIPN) in patients with early breast cancer receiving neo/adjuvant weekly paclitaxel.Methods: Patients were recruited from the National Cancer Centre Singapore and randomized (1:1) to receive either cryotherapy or usual care. Cryotherapy was applied as frozen gloves and socks on all extremities from 15 min before paclitaxel until 15 min post-infusion every cycle. Efficacy was measured by patient-reported outcomes (Patient Neurotoxicity Questionnaire [PNQ] and EORTC QLQ-CIPN20) and electrophysiological assessments. The primary endpoint was PNQ severity at 2 weeks after 12 cycles of weekly paclitaxel.Results: A total of 46 patients were recruited, of which 8 dropped out before paclitaxel treatment, leaving 38 evaluable. There was no significant difference in PNQ severity between cryotherapy and usual care at 2 weeks after paclitaxel treatment (sensory: p = 0.721; motor: p = 1.000). A benefit was observed at 3 months post-paclitaxel based on PNQ (sensory: 14.3 vs. 41.2%, p = 0.078; motor: 0 vs. 29.4%, p = 0.012) and CIPN20 (sensory: β = −3.6, 95%CI = −10.5–3.4, p = 0.308; motor: β = −7.3, 95%CI = −14.6–0, p = 0.051). Additionally, cryotherapy subjects have lower CIPN20 autonomic score (β = −5.84, 95%CI = −11.15 to −0.524, p = 0.031) and higher sympathetic skin response hand amplitudes (β = 0.544, 95%CI = 0.108–0.98, p = 0.014), suggesting possible autonomic benefits from cryotherapy. Temporary interruption with cryotherapy occurred in 80.9% of the subjects due to cold intolerance.Conclusions: There is insufficient evidence that cryotherapy prevents sensory neuropathy which may be due to the high rates of cryotherapy interruption in this study. The autonomic benefits of cryotherapy should be further investigated with appropriate outcome measures.Clinical Trial Registration:ClinicalTrials.gov: NCT03429972.

Background: The MONALEESA (ML)-2, -3, and -7 trials have shown a significant benefit in overall survival (OS) with ribociclib (RIB) + endocrine therapy (ET) over placebo (PBO) + ET in HR+/HER2− advanced breast cancer. HR+ breast cancer is a clinically and biologically heterogeneous disease, with identified intrinsic subtypes that vary in incidence, survival rate, and response to treatment. In a pooled analysis of the ML studies, patients with both luminal and HER2-enriched (HER2E) subtypes exhibited a consistent progression-free survival benefit with RIB + ET. The HER2E subtype (RIB, 14%; PBO, 11%), which is associated with ET resistance and poor outcomes, exhibited the greatest relative reduction in risk of progression or death (61%) with RIB + ET. Here, we report a pooled analysis of the ML-2, -3, and -7 trials, presenting OS by intrinsic subtype.. Methods: Tumor samples from patients enrolled in the ML-2, -3, and -7 trials underwent PAM50-based subtyping (blinded from clinical data), and the correlation between intrinsic subtype and OS was analyzed. Gene expression profiling of formalin-fixed, paraffin-embedded tumor samples was performed using a customized NanoString nCounter GX 800-gene panel. The prognostic and/or predictive relationship between PAM50-based subtypes and OS was evaluated using univariable and multivariable Cox proportional hazards models. Multivariable models were adjusted for known clinical prognostic factors, including age, prior chemotherapy, prior ET, ECOG performance status, visceral disease (presence of liver/lung metastases), bone-only metastases, histological grade, number of metastatic sites, tumor type, and de novo metastatic disease.. Results: From the pooled patient population (N = 2066), 997 tumor (71% primary) samples from the RIB (n = 585) and PBO (n = 412) arms of the ML trials (ML-2, n = 318; ML-3, n = 414; ML-7, n = 265) were profiled. Subtype distribution was consistent across treatment arms (Table). A similar benefit with RIB vs PBO was observed in the ITT (hazard ratio [HR], 0.76; 95% CI, 0.67-0.86) and biomarker (HR, 0.75; 95% CI, 0.63-0.89) populations. In both univariable and multivariable analyses, intrinsic subtype was prognostic for OS in both the RIB and PBO arms (P < .0001 for both arms); patients with luminal A subtype had the best OS outcomes in both arms, whereas patients with basal-like subtype had the worst OS outcomes. Intrinsic subtype was also predictive of OS (subtype-treatment interaction: P = .016 [univariable], P = .007 [multivariable]) with a consistent OS benefit with RIB treatment in all subtypes except for basal-like (Table). Patients with HER2E (HR, 0.60; P = .018), luminal B (HR, 0.69; P = .023), and luminal A (HR, 0.75; P = .021) subtypes all derived benefit from RIB. In patients with the basal-like subtype (n = 30), the HR was 1.89 (P = .148); these results should be interpreted with caution due to the small sample size (3% in each arm) and exploratory nature of this analysis.Conclusions: This pooled analysis of the ML trials confirmed the prognostic and predictive value of intrinsic subtype (PAM50 based) for OS. The addition of RIB to ET resulted in consistent OS benefit across all subtypes except for basal-like. The. consistent survival benefit in the HER2E subtype, which is associated with endocrine resistance and a very poor prognosis compared with luminal disease, warrants further investigation. SubtypeTreatment ArmDistribution, n (%)OS, median (95% CI), monthsHR (95% CI)P ValueaLuminal ARIB320 (55)68.0 (61.5-NR)0.75 (0.58-0.96).021PBO222 (54)54.6 (48.3-66.2)Luminal BRIB154 (26)58.8 (48.3-79.2)0.69 (0.50-0.95).023PBO124 (30)44.9 (35.5-52.6)HER2-enrichedRIB95 (16)40.3 (33.4-49.0)0.60 (0.40-0.92).018PBO52 (13)29.4 (23.9-42.0)Basal-likeRIB16 (3)19.4 (10.7-33.2)1.89 (0.80-4.47).148PBO14 (3)21.2 (12.8-NR)aP values are all two-sided. NR, not reached. Citation Format: Lisa Carey, Nadia Solovieff, Fabrice André, Joyce O'Shaughnessy, David A Cameron, Wolfgang Janni, Gabe S Sonke, Yoon-Sim Yap, Denise A Yardley, Juan Pablo Zarate, Tetiana Taran, Faye Su, Agnes Lteif, Aleix Prat. Correlative analysis of overall survival by intrinsic subtype across the MONALEESA-2, -3, and -7 studies of ribociclib + endocrine therapy in patients with HR+/HER2− advanced 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 GS2-00.

Background: MONALEESA-2 (ML-2) recently reported a statistically significant overall survival (OS) benefit with first-line ribociclib (RIB) + letrozole (LET) over placebo (PBO) + LET in postmenopausal patients with HR+/HER2- advanced breast cancer (ABC) (median, 63.9 vs 51.4 months; hazard ratio, 0.76; 95% CI, 0.63-0.93; P = .004). Understanding OS outcomes in clinically relevant subgroups of patients is important for improving personalized care and prognosis. Here, we report the results of a prespecified exploratory OS analysis in select patient subgroups by baseline location and number of metastatic sites.. Methods: Postmenopausal patients with HR+/HER2− ABC were randomized 1:1 to receive first-line RIB or PBO with LET. Prespecified exploratory OS analyses were performed for subgroups of special interest by baseline location (bone only [yes or no], liver involvement [yes or no], liver or lung involvement [yes or no]) and number of metastatic sites (< 3 or ≥ 3). The data are hypothesis generating since this analysis was exploratory and not powered for statistical significance.. Results: A total of 668 patients were included in the analysis. A consistent improvement in OS was observed with RIB + LET vs PBO + LET in all subgroups regardless of baseline metastatic site (Table). RIB + LET demonstrated an OS benefit over PBO + LET in clinically relevant subgroups by baseline location and number of metastatic sites, including subgroups of patients with liver metastases, liver or lung metastases, and ≥ 3 metastatic sites, who generally have a worse prognosis.. Conclusion: Consistent with the intent-to-treat population of ML-2, the results of this prespecified exploratory analysis demonstrated an OS benefit with RIB + LET independent of the site and number of metastatic lesions. TableTreatment Arm (n)HR (95% CI)Bone-only metastasisYesRIB + LET (69)0.78 (0.50-1.21)PBO + LET (79)NoRIB + LET (265)0.77(0.61-0.96)PBO + LET (255)Liver involvementYesRIB + LET (59)0.81 (0.54-1.24)PBO + LET (72)NoRIB + LET (275)0.77 (0.62-0.97)PBO + LET (262)Liver or lung involvementYesRIB + LET (182)0.81(0.62-1.05)PBO + LET (190)NoRIB + LET (152)0.71 (0.53-0.96)PBO + LET (144)No. of metastatic sites< 3RIB + LET (220)0.78(0.61-1.00)PBO + LET (222)≥ 3RIB + LET (114)0.71(0.51-0.98)PBO + LET (112) Citation Format: Joyce O'Shaughnessy, Salomon M Stemmer, Howard A Burris, Yoon-Sim Yap, Gabe Sonke, Lowell Hart, Mario Campone, Katarina Petrakova, Eric P Winer, Wolfgang Janni, Pierfranco Conte, David A Cameron, Fabrice André, Carlos Arteaga, Juan Pablo Zarate, Arunava Chakravartty, Tetiana Taran, Fabienne Le Gac, Paolo Serra, Gabriel N Hortobagyi. Overall survival subgroup analysis by metastatic site from the phase 3 MONALEESA-2 study of first-line ribociclib + letrozole in postmenopausal patients with advanced HR+/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 GS2-01.