Systemic therapy for hormone receptor-positive/human epidermal growth factor receptor 2-negative early stage and metastatic breast cancer.

Hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative breast cancer is defined by the presence of the estrogen receptor and/or the progesterone receptor and the absence of HER2 gene amplification. HR-positive/HER2-negative breast cancer accounts for 65%-70% of all breast cancers, and incidence increases with increasing age. Treatment varies by stage, and endocrine therapy is the mainstay of treatment in both early stage and late-stage disease. Combinations with cyclin-dependent kinase 4/6 inhibitors have reduced distant recurrence in the early stage setting and improved overall survival in the metastatic setting. Chemotherapy is used based on stage and tumor biology in the early stage setting and after endocrine resistance for advanced disease. New therapies, including novel endocrine agents and antibody-drug conjugates, are now changing the treatment landscape. With the availability of new treatment options, it is important to define the optimal sequence of treatment to maximize clinical benefit while minimizing toxicity. In this review, the authors first discuss the pathologic and molecular features of HR-positive/HER2-negative breast cancer and mechanisms of endocrine resistance. Then, they discuss current and emerging therapies for both early stage and metastatic HR-positive/HER2-negative breast cancer, including treatment algorithms based on current data.

Abemaciclib plus a nonsteroidal aromatase inhibitor as initial therapy for HR+, HER2- advanced breast cancer: final overall survival results of MONARCH 3.

BACKGROUND: In MONARCH 2, the addition of abemaciclib to fulvestrant significantly improved both progression-free survival (PFS) and overall survival (OS) in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) with disease progression on prior endocrine therapy. In MONARCH 3, the addition of abemaciclib to a nonsteroidal aromatase inhibitor (NSAI) as initial therapy for HR+, HER2- ABC significantly improved PFS. Here, we present the prespecified final OS results for MONARCH 3. PATIENTS AND METHODS: MONARCH 3 is a randomized, double-blind, phase III study of abemaciclib plus NSAI (anastrozole or letrozole) versus placebo plus NSAI in postmenopausal women with HR+, HER2- ABC without prior systemic therapy in the advanced setting. The primary objective was investigator-assessed PFS; OS was a gated secondary endpoint, and chemotherapy-free survival was an exploratory endpoint. RESULTS: A total of 493 women were randomized 2 : 1 to receive abemaciclib plus NSAI (n = 328) or placebo plus NSAI (n = 165). After a median follow-up of 8.1 years, there were 198 OS events (60.4%) in the abemaciclib arm and 116 (70.3%) in the placebo arm (hazard ratio, 0.804; 95% confidence interval 0.637-1.015; P = 0.0664, non-significant). Median OS was 66.8 versus 53.7 months for abemaciclib versus placebo. In the subgroup with visceral disease, there were 113 OS events (65.3%) in the abemaciclib arm and 65 (72.2%) in the placebo arm (hazard ratio, 0.758; 95% confidence interval 0.558-1.030; P = 0.0757, non-significant). Median OS was 63.7 months versus 48.8 months for abemaciclib versus placebo. The previously demonstrated PFS benefit was sustained, and chemotherapy-free survival numerically improved with the addition of abemaciclib. No new safety signals were observed. CONCLUSIONS: Abemaciclib combined with an NSAI resulted in clinically meaningful improvement in median OS (intent-to-treat population: 13.1 months; subgroup with visceral disease: 14.9 months) in patients with HR+ HER2- ABC; however, statistical significance was not reached.

Genomic and transcriptomic profiles associated with response to eribulin and nivolumab combination in HER-2-negative metastatic breast cancer.

BACKGROUND: Biomarkers for predicting response to the immunotherapy and chemotherapy combination in breast cancer patients are not established. In this study, we report exploratory genomic and transcriptomic analyses of pretreatment tumor tissues from patients enrolled in phase II clinical trial of a combination of eribulin and nivolumab for HER-2-negative metastatic breast cancer (MBC) (KORNELIA trial, NCT04061863). METHODS: We analyzed associations between tumor molecular profiles based on genomic (n = 76) and transcriptomic data (n = 58) and therapeutic efficacy. Patients who achieved progression-free survival (PFS) ≥ 6 months were defined as PFS6-responders and PFS6-nonresponders otherwise. FINDINGS: Analyses on tumor mutation burden (TMB) showed a tendency toward a favorable effect on efficacy, while several analyses related to homologous recombination deficiency (HRD) indicated a potentially negative impact on efficacy. Patients harboring TP53 mutations showed significantly poor PFS6 rate and PFS, which correlated with the enrichment of cell cycle-related signatures in PFS6-nonresponders. High antigen presentation gene set enrichment scores (≥ median) were significantly associated with longer PFS. Naïve B-cell and plasma cell proportions were considerably higher in long responders (≥ 18 months). INTERPRETATION: Genomic features including TMB, HRD, and TP53 mutations and transcriptomic features related to immune cell profiles and cell cycle may distinguish responders. Our findings provide insights for further exploring the combination regimen and its biomarkers in these tumors.

Patterns of chemotherapy receipt among patients with hormone receptor-positive, HER2-negative breast cancer.

BACKGROUND: Breast cancer chemotherapy utilization not only may differ by race and age, but also varies by genomic risk, tumor characteristics, and patient characteristics. Studies in demographically diverse populations with both clinical and genomic data are necessary to understand potential disparities by race and age. METHODS: In the Carolina Breast Cancer Study Phase 3 (2008-2013), chemotherapy receipt (yes/no) and regimen type were assessed in association with age and race among hormone receptor (HR) positive and HER2-negative tumors (n = 1862). Odds ratios were estimated for the association between demographic factors and chemotherapy receipt. RESULTS: Monotonic decreases in frequency of adjuvant chemotherapy receipt were observed over time during the study period, while neoadjuvant chemotherapy was stable. Younger age was associated with chemotherapy receipt (OR [95% CI]: 2.9 [2.4, 3.6]) and with anthracycline-based regimens (OR [95% CI]: 1.7 [1.3, 2.4]). Participants who had Medicaid (OR [95% CI]: 1.8 [1.3, 2.5]), lived in rural settings (OR [95% CI]: 1.4 [1.0, 2.0]), or were Black (OR [95% CI]: 1.5 [1.2, 1.8]) had slightly higher odds of chemotherapy, but these associations were non-significant with adjustment for stage and grade. Associations between younger age and chemotherapy receipt were strongest among women who did not receive genomic testing. CONCLUSIONS: While race was not strongly associated with chemotherapy receipt, younger age remains a strong predictor of chemotherapy receipt, even with adjustment for clinical factors and among women who receive genomic testing.

A network meta-analysis of efficacy and safety for first-line and second/further-line therapies in postmenopausal women with hormone receptor-positive, HER2-negative, advanced breast cancer.

BACKGROUND: Hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR + /HER2 -) advanced breast cancer is a prevalent subtype among postmenopausal women. Despite the growing number of randomized clinical trials (RCTs) exploring this topic, the efficacy and safety of first-line and second/further-line treatments remain uncertain. Accordingly, our aim was to conduct a comprehensive evaluation of the efficacy and safety of these therapies through network meta-analysis. METHODS: RCTs were identified by searching Pubmed, Embase, and major cancer conferences. The efficacy of interventions was assessed using the hazard ratios (HRs) of progression-free survival (PFS) and overall survival (OS), while safety was indicated by the incidence of any grade adverse events (AEs), grade 3-5 AEs, AEs leading to treatment discontinuation, and AEs leading to death. Both time-variant HRs fractional polynomial models and time-invariant HRs Cox-proportional hazards models were considered for handling time-to-event data. Safety indicators were analyzed using Bayesian network meta-analysis. Additionally, subgroup analyses were conducted based on patient characteristics. RESULTS: A total of 41 RCTs (first-line 17, second/further-lines 27) were included in the analysis. For first-line treatment, the addition of Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors to endocrine therapy significantly improved therapeutic efficacy in terms of both PFS and OS, demonstrating the best performance across all mechanisms. Specifically, the combination of Abemaciclib and Letrozole demonstrated the most favorable performance in terms of PFS, while Ribociclib plus Fulvestrant yielded the best outcomes in OS. Incorporating the immune checkpoint inhibitor Avelumab into the regimen with CDK4/6 inhibitors and selective estrogen receptor degraders significantly enhanced both PFS and OS in second-line or later treatments. Regarding safety, endocrine monotherapy performed well. Regarding safety, endocrine monotherapy performed well. There is mounting evidence suggesting that most CDK4/6 inhibitors may demonstrate poorer performance with respect to hematologic AEs. However, additional evidence is required to further substantiate these findings. CONCLUSIONS: CDK4/6 inhibitors, combined with endocrine therapy, are pivotal in first-line treatment due to their superior efficacy and manageable AEs. For second/further-line treatment, adding immune checkpoint inhibitors to CDK4/6 inhibitors plus endocrine therapy may produce promising results. However, to reduce the results' uncertainty, further trials comparing these novel treatments are warranted. TRIAL REGISTRATION: Registration number: PROSPERO (CRD42022377431).

The treatment pattern of advanced HR-positive and HER2-negative breast cancer in central southern China: a hospital-based cross-sectional study.

AIMS: This investigation aims to elucidate the treatment status of advanced HR+/HER2- breast cancer patients in Hunan Province of Central Southern China from November 2021 to December 2022. METHODS: Data from 301 patients with advanced HR+/HER2- breast cancer were collected from the breast cancer investigation project in Hunan under the guidance of the Chinese Society of Clinical Oncolfogy (CSCO). The data included the clinical characteristics of patients and the status of first-line and second-line rescue treatment. RESULTS: First-line chemotherapy and endocrine therapy for mBC accounted for 40% (121/301) and 60% (180/301) of treatments, respectively. AI (21%), AI plus CDK4/6 inhibitor (28%), and fulvestrant (24%) or fulvestrant plus CDK4/6 inhibitor (18%) were the most common first-line endocrine therapies. Taxane-based chemotherapy was the most common first-line chemotherapy (59%). Second-line chemotherapy and endocrine therapy for mBC accounted for 43% (72/166) and 57% (94/166) of treatments, respectively. Fulvestrant (23%) or fulvestrant plus CDK4/6 inhibitor (29%) were the most common second-line endocrine therapies. The prevalences of AI and AI plus CDK4/6 inhibitor decreased to 19% and 11%, respectively. T (taxane)-based chemotherapy was still the most common chemotherapy regimen (46%). Third-line chemotherapy was more prevalent than endocrine therapy (57% vs. 41%). T (taxane)-based chemotherapy was still the most common chemotherapy regimen (46%). Fulvestrant plus CDK4/6 inhibitor was the most common endocrine therapy (33%). AI, AI plus CDK4/6 inhibitor, and fulvestrant accounted for 21%, 12% and 18% of third-line endocrine therapies, respectively. CONCLUSIONS: Compared to chemotherapy, endocrine therapy was a more favorable choice for first-line and second-line treatment for HR+/HER2- advanced breast cancer patients in Hunan Province.

Neoadjuvant Therapy: Current Landscape and Future Horizons for ER-Positive/HER2-Negative and Triple-Negative Early Breast Cancer.

OPINION STATEMENT: Navigating the complex landscape of breast cancer treatment involves distinct strategies for luminal and triple-negative subtypes. While neoadjuvant chemotherapy historically dominates the approach for aggressive triple-negative tumors, recent evidence highlights the transformative impact of immunotherapy, alongside chemotherapy, in reshaping treatment paradigms. In luminal cancers, endocrine therapy, notably aromatase inhibitors, demonstrates promising outcomes in postmenopausal patients with low-grade luminal A tumors. However, integrating targeted therapies like CDK4/6 inhibitors in neoadjuvant setting remains inconclusive. Identifying predictive factors for treatment response, especially in luminal tumors, poses a challenge, emphasizing the necessity for ongoing research. A multidisciplinary approach, tailored to individual patient profiles, is crucial for maximizing efficacy while minimizing toxicity. As we strive to optimize breast cancer management, a comprehensive understanding of the distinct characteristics and treatment implications of luminal and triple-negative subtypes, including the transformative role of immunotherapy, is essential for informed decision-making and personalized care.

A plain language summary of the TROPiCS-02 study in patients with breast cancer (HR-positive/HER2-negative).

WHAT IS THIS SUMMARY ABOUT?: Sacituzumab govitecan (brand name: TRODELVY®) is a new treatment for certain types of advanced or metastatic breast cancer. One common type of breast cancer has at least 1 of 2 hormone receptors (HR positive) and does not have human epidermal growth factor 2 (HER2 negative). The HR and HER2 receptors are known to influence how severe a case of breast cancer is. Certain treatments will only work if a specific receptor is present on breast cancer cells. HR-positive/HER2-negative advanced or metastatic breast cancer can be treated with sacituzumab govitecan. This is a summary of the results of the TROPiCS-02 study. This study compared sacituzumab govitecan with standard chemotherapy in participants with HR-positive/HER2-negative advanced or metastatic breast cancer. WHAT WERE THE RESULTS?: The study showed that participants treated with sacituzumab govitecan lived significantly longer without their cancer getting worse than participants treated with chemotherapy. Participants also survived significantly longer and their tumors became significantly smaller in more participants treated with sacituzumab govitecan than with chemotherapy. In general, participants treated with sacituzumab govitecan were more likely to have side effects and had more severe side effects. These side effects included low levels of a type of white blood cell known as neutrophils and diarrhea. Oncologists (doctors that treat cancer) know of these side effects as they are common among people being treated for cancer. Doctors can control these side effects by following standard treatment guidelines and the package insert for sacituzumab govitecan. Participants treated with sacituzumab govitecan maintained their sense of well-being and ability to do daily activities (quality of life) longer than participants treated with chemotherapy. It also took longer for fatigue and other symptoms of cancer to worsen in participants treated with sacituzumab govitecan compared with chemotherapy. WHAT DO THE RESULTS MEAN?: Sacituzumab govitecan is more effective than standard chemotherapies for people who have already received multiple treatments for HR-positive/ HER2-negative advanced breast cancer. The side effects from sacituzumab govitecan could generally be managed well by doctors. Although there were more side effects with sacituzumab govitecan than with chemotherapy, they were generally mild to moderate.

TROPION-Breast01: Datopotamab deruxtecan vs chemotherapy in pre-treated inoperable or metastatic HR+/HER2- breast cancer.

Improving the prognosis for patients with metastatic HR+/HER2- breast cancer remains an unmet need. Patients with tumors that have progressed on endocrine therapy and/or are not eligible for endocrine therapy had limited treatment options beyond chemotherapy. Antibody-drug conjugates are a novel and promising treatment class in this setting. Datopotamab deruxtecan (Dato-DXd) consists of a TROP2-directed humanized IgG1 monoclonal antibody attached via a serum-stable cleavable linker to a topoisomerase I inhibitor payload. TROPION-Breast01 is an ongoing phase III study that is evaluating the efficacy and safety of Dato-DXd compared with investigator's choice of standard-of-care chemotherapy in patients with inoperable or metastatic HR+/HER2- breast cancer who have received one or two prior lines of systemic chemotherapy in the inoperable or metastatic setting. Clinical Trial Registration: NCT05104866 (ClinicalTrials.gov).

Antibody-drug conjugates are a type of drug with two parts: an antibody that directs the drug to the cancer cells and a cancer-cell killing toxic payload. By binding to cancer cells before releasing the payload, treatment is directed to the site of action so there are fewer side effects in the rest of the body. Datopotamab deruxtecan (Dato-DXd) is an antibody-drug conjugates made up of datopotamab (antibody) and DXd (payload) which are joined together via a stable linker. Datopotamab binds to a protein found on cancer cells called TROP2; it then goes inside and releases the DXd payload to kill the tumor cells. DXd may leak out to surrounding cancer cells and kill those as well. The TROPION-Breast01 study is comparing Dato-DXd with standard-of-care chemotherapy. Around 700 patients will take part, who have: Tumors that cannot be surgically removed. Tumors that are hormone receptor-positive and do not have HER2 overexpression. Had one or two lines of previous chemotherapy (after the tumor could not be surgically removed, or had spread). Had tumor growth despite hormonal therapy or are ineligible for hormonal therapy. Patients who meet the entry criteria will be randomly assigned to a treatment group in equal numbers to either Dato-DXd or an appropriate chemotherapy, out of four options chosen by the treating doctor. At the end of the study, researchers will look at whether the patients who receive Dato-DXd live longer without their breast cancer getting worse, compared with patients who receive chemotherapy. This study is also looking at how the treatment affects patients' quality of life.

Identification of a Panel of miRNAs Associated with Resistance to Palbociclib and Endocrine Therapy.

We investigated whether we could identify a panel of miRNAs associated with response to treatment in tumor tissues of patients with Hormone Receptor-positive/HER2-negative metastatic breast cancer treated with endocrine therapy (ET) and the CDK4/6 inhibitor (CDK4/6i)i palbociclib. In total, 52 patients were evaluated, with 41 receiving treatment as the first line. The overall median PFS was 20.8 months (range 2.5-66.6). In total, 23% of patients experienced early progression (<6 months). Seven miRNAs (miR-378e, miR-1233, miR-99b-5p, miR-1260b, miR-448, -miR-1252-5p, miR-324-3p, miR-1233-3p) showed a statistically significant negative association with PFS. When we considered PFS < 6 months, miR-378e, miR-99b-5p, miR-877-5p, miR-1297, miR-455-5p, and miR-4536-5p were statistically associated with a poor outcome. In the multivariate analysis, the first three miRNAs confirmed a significant and independent impact on PFS. The literature data and bioinformatic tools provide an underlying molecular rationale for most of these miRNAs, mainly involving the PI3K/AKT/mTOR pathway and cell-cycle machinery as cyclin D1, CDKN1B, and protein p27Kip1 and autophagy. Our findings propose a novel panel of miRNAs associated with a higher likelihood of early progression in patients treated with ET and Palbociclib and may contribute to shed some light on the mechanisms of de novo resistance to CDK4/6i, but this should be considered exploratory and evaluated in larger cohorts.

Three-Week Versus 4-Week Schedule of nab-Paclitaxel in Patients With Metastatic Breast Cancer: A Randomized Phase II Study.

BACKGROUND: This head-to-head study compared a 3-week versus 4-week schedule of nab-paclitaxel in patients with metastatic breast cancer (mBC). METHODS: Patients with HER2-negative mBC were enrolled and randomly assigned (1:1) to receive nab-paclitaxel for a 3-week schedule (125 mg/m2 on days 1 and 8) or a 4-week schedule (same dose on days 1, 8, and 15) until disease progression or treatment intolerance. Patients with intolerable toxicities were allowed to receive a maintenance regimen after benefiting from nab-paclitaxel. The primary endpoint was progression-free survival (PFS). RESULTS: Ninety-four patients were included in the analysis (n = 47 in each arm). A longer median PFS (mPFS) was observed in the 3-week versus the 4-week schedule in the overall population (not reached vs. 6.8 months; hazard ratio [HR] = 0.44; P = .029). Patients in the 2 arms had a similar overall survival (28.0 vs. 25.8 months), objective response rate (51.1% vs. 48.9%), and disease control rate (93.6% vs. 80.9%). The 3-week schedule was associated with a lower rate of toxicity-related treatment discontinuation (8.5% vs. 29.8%) and dose delays (6.4% vs. 23.4%). CONCLUSION: This study demonstrated the better antitumor activity and safety profile of a 3-week over 4-week nab-paclitaxel schedule in HER2-negative mBC, suggesting that a 3-week schedule may be a better treatment regimen in clinical practice (ClinicalTrials.gov Identifier: NCT04192331).

Adjuvant chemotherapy in patients with ER-negative/HER2-negative, T1abN0 breast cancer: a nationwide study.

PURPOSE: The purpose of this study was to examine the effect of chemotherapy on invasive disease-free survival (iDFS) and overall survival (OS) in a nationwide cohort of patients with estrogen receptor (ER)-negative/human epidermal growth factor receptor 2 (HER2)-negative, T1abN0 breast cancer. METHODS: Patients with ER-negative/HER2-negative, T1abN0 breast cancer registered in the Danish Breast Cancer Group database between 2007 and 2016 were identified. The effect of adjuvant chemotherapy on iDFS and OS was analyzed with Cox proportional hazards analysis. RESULTS: In total, 296 patients were included in the statistical analyses. Of these, 235 (79.4%) received chemotherapy and 61 patients (20.6%) did not. Patients treated with chemotherapy were significantly younger, had a significantly higher proportion of grade 3 tumors, T1b tumors, and tumors of ductal subtype. With 7.7 years of median follow-up, treatment with chemotherapy was associated with a significant improvement in OS in the adjusted analysis, Hazard Ratio 0.35 (95% Confidence Interval (0.15-0.81), p = 0.02), chemotherapy vs. no chemotherapy. In the unadjusted analyses, patients with both T1a and T1b tumors had significantly improved OS with chemotherapy. At 5 years, OS was 100% vs. 94.4% and 93.8% vs. 81.3% for patients with T1a and T1b tumors, respectively, chemotherapy vs. no chemotherapy. With 4.9 years of median follow-up, iDFS was not significantly improved with chemotherapy. CONCLUSION: Patients with ER-negative/HER2-negative, T1abN0 breast cancer had significantly improved OS when treated with chemotherapy. This improvement was significant in patients with both T1a and T1b tumors, respectively. The effect was, however, limited in patients with T1a tumors.

Pegylated liposomal doxorubicin (Duomeisu®) monotherapy in patients with HER2-negative metastatic breast cancer heavily pretreated with anthracycline and taxanes: a single-arm, phase II study.

PURPOSE: To evaluate the efficacy and safety of pegylated liposomal doxorubicin (PLD) in patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC) heavily pretreated with anthracycline and taxanes. METHODS: In this single-arm, phase II study, patients with HER2-negative MBC previously treated with anthracycline and taxanes as second- to fifth chemotherapy received PLD (Duomeisu®, generic doxorubicin hydrochloride liposome) 40 mg/m2 every 4 weeks until disease progression, unacceptable toxicity, or completion of six cycles. Primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR), and safety. RESULTS: Of 44 enrolled patients (median age, 53.5 years; range, 34-69), 41 and 36 were evaluable for safety and efficacy, respectively. In total, 59.1% (26/44) of patients had ≥ 3 metastatic sites, 86.4% (38/44) had visceral disease, and 63.6% (28/44) had liver metastases. Median PFS was 3.7 months (95% confidence interval [CI] 3.3-4.1) and median OS was 15.0 months (95% CI 12.1-17.9). ORR, DCR, and CBR were 16.7%, 63.9%, and 36.1%, respectively. The most common adverse events (AEs) were leukopenia (53.7%), fatigue (46.3%), and neutropenia (41.5%), with no grade 4/5 AEs. The most common grade 3 AEs were neutropenia (7.3%) and fatigue (4.9%). Patients experienced palmar-plantar-erythrodysesthesia (24.4%, 2.4% grade 3), stomatitis (19.5%, 7.3% grade 2), and alopecia (7.3%). One patient displayed a left ventricular ejection fraction decline of 11.4% from baseline after five cycles of PLD therapy. CONCLUSION: PLD (Duomeisu®) 40 mg/m2 every 4 weeks was effective and well-tolerated in patients with HER2-negative MBC heavily pretreated with anthracycline and taxanes, revealing a potentially viable treatment option for this population. Trial registration Chinese Clinical Trial Registry: ChiCTR1900022568.

Long-term outcomes of high-risk HR-positive and HER2-negative early breast cancer patients from GEICAM adjuvant studies and El Álamo IV registry.

PURPOSE: The monarchE trial showed that the addition of abemaciclib improves efficacy in patients with high-risk early breast cancer (EBC). We analyzed the long-term outcomes of a population similar to the monarchE trial to put into context the potential benefit of abemaciclib. METHODS: HR-positive/HER2-negative EBC patients eligible for the monarchE study were selected from 3 adjuvant clinical trials and a breast cancer registry. Patients with ≥ 4 positive axillary lymph nodes (N +) or 1-3 N + with tumor size ≥ 5 cm and/or histologic grade 3 and/or Ki67 ≥ 20%, who had undergone surgery with curative intent and had received anthracyclines ± taxanes and endocrine therapy in the neoadjuvant and /or adjuvant setting were included. We performed analysis of Invasive Disease-Free Survival (iDFS), Distant Disease-Free Survival (dDFS) and Overall Survival (OS) at 5 and 10 years, as well as yearly (up to 10) of Invasive Relapse Rate (IRR), Distant Relapse Rate (DRR) and Death Rate (DR). RESULTS: A total of 1,617 patients were analyzed from the GEICAM-9906 (312), GEICAM-2003-10 (210), and GEICAM-2006-10 (160) trials plus 935 from El Álamo IV. With a median follow-up of 10.1 years, the 5 and 10 years iDFS rates were 75.2% and 57.0%, respectively. The dDFS and OS rates at 5 years were 77.4% and 88.8% and the respective figures at 10 years were 59.7% and 70.9%. CONCLUSIONS: This data points out the need for new therapies for those patients. A longer follow-up of the monarchE study to see the real final benefit with abemaciclib is warranted. TRIAL REGISTRATION: ClinTrials.gov: GEICAM/9906: NCT00129922; GEICAM/ 2003-10: NCT00129935 and GEICAM/ 2006-10: NCT00543127.

Phase II trial of biweekly administration with eribulin after three cycles of induction therapy in hormone receptor-positive, HER2-negative metastatic breast cancer (JACCRO BC-03).

PURPOSE: Metastatic breast cancer (MBC) is usually incurable; treatment aims to maximize patients' function and quality of life (QOL). Eribulin is a standard treatment in patients with MBC pretreated with anthracycline and taxane; however, the best administration schedule is unknown. METHODS: In this prospective phase II trial of patients with luminal MBC, we administered biweekly eribulin to patients who completed a three-cycle induction treatment. RESULTS: Sixty patients with hormone-receptor-positive and HER2-negative MBC were enrolled; 40 obtained stable disease (SD) or better efficacy after induction therapy, after which they were switched to biweekly maintenance administration. The median progression-free survival (PFS) in patients who switched to maintenance therapy was 15.21 weeks (95% CI 9.71-22.14), starting on the first day of maintenance therapy. Overall survival (OS) in patients who switched to maintenance therapy was 21.39 months (95% CI 18.89-32.89). PFS and OS in the whole population starting from the registration date were 19.00 weeks (95% CI 17.00-25.00) and 21.52 months (95% CI 16.23-24.25), respectively. PFS from the enrollment date for patients who received maintenance therapy was 25.29 weeks (95% CI 19.14-32.14). Patients who achieved complete response or partial response during induction therapy had significantly longer PFS compared to patients with SD. CONCLUSION: The efficacy of biweekly administration of eribulin at maintenance was nonsignificant. However, less frequent visits are convenient, and reduced dose intensity improves safety. Biweekly administration, besides dose reduction, could be an acceptable option for patients who are unable to maintain a standard regimen.

Impact of the OncotypeDX score and HER2 RNA PCR levels on HER2-low IHC levels in primary and metastasized tumors.

PURPOSE: One-half of hormone receptor-positive (HR +) breast cancer (BC) patients have low expression of HER2 (HER2-low) and may benefit from trastuzumab deruxtecan (TDXd). This study aimed to identify parameters associated with HER2-low levels in primary and metastatic tumors. We specifically sought to determine whether OncotypeDX and HER2 mRNA levels could identify patients who would otherwise be considered HER2-negative by immunohistochemistry (IHC). METHODS: This retrospective analysis of all consecutive HR + patients who underwent OncotypeDX from January 2004 to December 2020 was conducted in a single medical center (n = 1429). We divided HER2-negative cases into HER2-low (IHC = 1 + or 2 + and non-amplified fluorescent situ hybridization) and HER2-0 (IHC = 0). HER2 RT-PCR was evaluated from the OncotypeDX results. RESULTS: HER2-low cases exhibited significantly higher HER2 RT-PCR scores (p = 2.1e-9), elevated estrogen receptor (ER) levels (p = 0.0114), and larger tumor sizes compared to HER2-0 cases (> 2 cm; 36.6% vs. 22.1%, respectively, p < 0.00001). Primary tumors > 2 cm were more likely to be HER2-low (OR = 2.07, 95% CI: 1.6317 to 2.6475, p < 0.0001). Metastatic BCs expressed higher HER2 IHC scores compared with primary BCs (Wilcoxon signed-rank, p = 0.046). HER2 IHC scores were higher for low-risk vs. medium-risk OncotypeDX (p = 0.0067). No other clinical or pathological parameters were associated with the increase in HER2 levels in the metastatic samples. CONCLUSION: It might be beneficial to use clinical data from the primary tumor, including the HER2 RT-PCR score, to determine a HER2-low status.

Advances in Endocrine Therapy for Hormone Receptor-Positive Advanced Breast Cancer.

PURPOSE OF REVIEW: To provide an overview of the current management of hormone receptor-positive (HR +) advanced breast cancer as well as highlight ongoing clinical investigation and novel therapies in development. RECENT FINDINGS: CDK4/6 inhibition plus endocrine therapy is standard front-line therapy for HR + advanced breast cancer. Continuation of CDK4/6 inhibitors in combination with alternative endocrine therapy has been evaluated in the second-line setting. Alternatively, endocrine therapy in combination with PI3K/AKT pathway targeting agents has been studied, particularly in patients with PI3K pathway alterations. The oral SERD elacestrant has also been evaluated in patients with ESR1 mutation. Many novel endocrine agents and targeted agents are in development. An improved understanding of combination therapies and sequencing of therapies is needed to optimize the treatment paradigm. Biomarker development is needed to guide treatment decisions. Advances in the treatment of HR + breast cancer have resulted in improved patient outcomes in recent years. Continued development efforts with identification of biomarkers to better understand response and resistance to therapy are needed.

Treatment efficacy of ribociclib or palbociclib plus letrozole in hormone receptor-positive/HER2-negative metastatic breast cancer.

Background: Ribociclib, palbociclib and abemaciclib are currently approved CDK4/6 inhibitors along with aromatase inhibitors as the first-line standard-of-care for patients with hormone receptor-positive, HER2-negative metastatic breast cancer. Methods: The authors report retrospective real-life data for 600 patients with estrogen receptor- and/or progesterone receptor-positive and HER2-negative metastatic breast cancer who were treated with ribociclib and palbociclib in combination with letrozole. Results & conclusion: The results demonstrated that the combination of palbociclib or ribociclib with letrozole has similar progression-free survival and overall survival benefit in real life for the patient group with similar clinical features. Specifically, endocrine sensitivity may be a factor to be considered in the treatment preference.

Neoadjuvant treatment and survival outcomes by pathologic complete response in HER2-negative early breast cancers.

Background: The benefit of pathologic complete response (pCR) in early breast cancer (eBC) is not well described in the real-world setting. This study used the nationwide Flatiron Health electronic health record-derived deidentified database to describe treatment patterns and survival outcomes by pCR status after neoadjuvant therapy (NAT) in women with triple-negative or HR+/HER2- eBC. Materials & methods: Observational cohort study analyzing women with eBC who started NAT between 2011 and 2018. Results: 496 women were included in the study; of those, 16.1% achieved pCR, of which 35.7% were triple-negative and 6.1% were HR+/HER2- eBC. More women with triple-negative eBC (95.2%) were exclusively treated with chemotherapy-based NAT versus HR+/HER2- eBC (56.1%). In multivariate analyses from NAT start, not achieving pCR was associated with increased risk of death and progression. Conclusion: pCR status may be a reliable prognostic indicator for survival in these eBC subtypes in the real-world setting.

Response to treatment before surgery indicates better outcomes in breast cancer patients. To understand how well cancer treatments work, patients are compared on their overall survival. This measures the number of people in a study or treatment group who are still alive after a certain amount of time from when they were diagnosed or started treatment. Overall survival shows how well patients are doing in their cancer journey, but it takes time to understand how good treatments are when using this measure. In women with early-stage breast cancer, a quicker way to understand how well patients react to their treatment is called pathologic complete response (pCR). Some people have whole-body treatments such as chemotherapy before surgery (known as neoadjuvant treatment). For these patients, pCR may occur after neoadjuvant treatment, meaning all signs of cancer are gone when they have surgery. In real-life clinical settings, little research has been done to understand how pCR can measure breast cancer survival. In this study, the authors investigate whether women who had a pCR were more or less likely to have their cancer become worse or experience death than those who did not achieve pCR. The health records of 496 women diagnosed with early breast cancer over an eight-year period were assessed. The results show that women who did not have a pCR were more likely to have their cancer become worse or die. This means that pCR could be a better way than overall survival to identify which treatments work well in early breast cancer, and importantly, change the course of a patient's journey.

Targeting the histone demethylase PHF8-mediated PKCα-Src-PTEN axis in HER2-negative gastric cancer.

Targeted treatments for advanced gastric cancer (GC) are needed, particularly for HER2-negative GC, which represents the majority of cases (80 to 88%). In this study, in silico analyses of the lysine histone demethylases (KDMs) involved in diverse biological processes and diseases revealed that PHD finger protein 8 (PHF8, KDM7B) was significantly associated with poor clinical outcome in HER2-negative GC. The depletion of PHF8 significantly reduced cancer progression in GC cells and in mouse xenografts. PHF8 regulated genes involved in cell migration/motility based on a microarray analysis. Of note, PHF8 interacted with c-Jun on the promoter of PRKCA which encodes PKCα. The depletion of PHF8 or PKCα greatly up-regulated PTEN expression, which could be rescued by ectopic expression of a PKCα expression vector or an active Src. These suggest that PTEN destabilization occurs mainly via the PKCα-Src axis. GC cells treated with midostaurin or bosutinib significantly suppressed migration in vitro and in zebrafish models. Immunohistochemical analyses of PHF8, PKCα, and PTEN showed a positive correlation between PHF8 and PKCα but negative correlations between PHF8 and PTEN and between PKCα and PTEN. Moreover, high PHF8-PKCα expression was significantly correlated with worse prognosis. Together, our results suggest that the PKCα-Src-PTEN pathway regulated by PHF8/c-Jun is a potential prognostic/therapeutic target in HER2-negative advanced GC.