Ribociclib plus Endocrine Therapy in Early Breast Cancer.

BACKGROUND: Ribociclib has been shown to have a significant overall survival benefit in patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. Whether this benefit in advanced breast cancer extends to early breast cancer is unclear. METHODS: In this international, open-label, randomized, phase 3 trial, we randomly assigned patients with HR-positive, HER2-negative early breast cancer in a 1:1 ratio to receive ribociclib (at a dose of 400 mg per day for 3 weeks, followed by 1 week off, for 3 years) plus a nonsteroidal aromatase inhibitor (NSAI; letrozole at a dose of 2.5 mg per day or anastrozole at a dose of 1 mg per day for ≥5 years) or an NSAI alone. Premenopausal women and men also received goserelin every 28 days. Eligible patients had anatomical stage II or III breast cancer. Here we report the results of a prespecified interim analysis of invasive disease-free survival, the primary end point; other efficacy and safety results are also reported. Invasive disease-free survival was evaluated with the use of the Kaplan-Meier method. The statistical comparison was made with the use of a stratified log-rank test, with a protocol-specified stopping boundary of a one-sided P-value threshold of 0.0128 for superior efficacy. RESULTS: As of the data-cutoff date for this prespecified interim analysis (January 11, 2023), a total of 426 patients had had invasive disease, recurrence, or death. A significant invasive disease-free survival benefit was seen with ribociclib plus an NSAI as compared with an NSAI alone. At 3 years, invasive disease-free survival was 90.4% with ribociclib plus an NSAI and 87.1% with an NSAI alone (hazard ratio for invasive disease, recurrence, or death, 0.75; 95% confidence interval, 0.62 to 0.91; P = 0.003). Secondary end points - distant disease-free survival and recurrence-free survival - also favored ribociclib plus an NSAI. The 3-year regimen of ribociclib at a 400-mg starting dose plus an NSAI was not associated with any new safety signals. CONCLUSIONS: Ribociclib plus an NSAI significantly improved invasive disease-free survival among patients with HR-positive, HER2-negative stage II or III early breast cancer. (Funded by Novartis; NATALEE ClinicalTrials.gov number, NCT03701334.).

Cycling cancer persister cells arise from lineages with distinct programs.

Non-genetic mechanisms have recently emerged as important drivers of cancer therapy failure1, where some cancer cells can enter a reversible drug-tolerant persister state in response to treatment2. Although most cancer persisters remain arrested in the presence of the drug, a rare subset can re-enter the cell cycle under constitutive drug treatment. Little is known about the non-genetic mechanisms that enable cancer persisters to maintain proliferative capacity in the presence of drugs. To study this rare, transiently resistant, proliferative persister population, we developed Watermelon, a high-complexity expressed barcode lentiviral library for simultaneous tracing of each cell's clonal origin and proliferative and transcriptional states. Here we show that cycling and non-cycling persisters arise from different cell lineages with distinct transcriptional and metabolic programs. Upregulation of antioxidant gene programs and a metabolic shift to fatty acid oxidation are associated with persister proliferative capacity across multiple cancer types. Impeding oxidative stress or metabolic reprogramming alters the fraction of cycling persisters. In human tumours, programs associated with cycling persisters are induced in minimal residual disease in response to multiple targeted therapies. The Watermelon system enabled the identification of rare persister lineages that are preferentially poised to proliferate under drug pressure, thus exposing new vulnerabilities that can be targeted to delay or even prevent disease recurrence.

Trastuzumab Deruxtecan versus Trastuzumab Emtansine for Breast Cancer.

BACKGROUND: Trastuzumab emtansine is the current standard treatment for patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer whose disease progresses after treatment with a combination of anti-HER2 antibodies and a taxane. METHODS: We conducted a phase 3, multicenter, open-label, randomized trial to compare the efficacy and safety of trastuzumab deruxtecan (a HER2 antibody-drug conjugate) with those of trastuzumab emtansine in patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane. The primary end point was progression-free survival (as determined by blinded independent central review); secondary end points included overall survival, objective response, and safety. RESULTS: Among 524 randomly assigned patients, the percentage of those who were alive without disease progression at 12 months was 75.8% (95% confidence interval [CI], 69.8 to 80.7) with trastuzumab deruxtecan and 34.1% (95% CI, 27.7 to 40.5) with trastuzumab emtansine (hazard ratio for progression or death from any cause, 0.28; 95% CI, 0.22 to 0.37; P<0.001). The percentage of patients who were alive at 12 months was 94.1% (95% CI, 90.3 to 96.4) with trastuzumab deruxtecan and 85.9% (95% CI, 80.9 to 89.7) with trastuzumab emtansine (hazard ratio for death, 0.55; 95% CI, 0.36 to 0.86; prespecified significance boundary not reached). An overall response (a complete or partial response) occurred in 79.7% (95% CI, 74.3 to 84.4) of the patients who received trastuzumab deruxtecan and in 34.2% (95% CI, 28.5 to 40.3) of those who received trastuzumab emtansine. The incidence of drug-related adverse events of any grade was 98.1% with trastuzumab deruxtecan and 86.6% with trastuzumab emtansine, and the incidence of drug-related adverse events of grade 3 or 4 was 45.1% and 39.8%, respectively. Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 10.5% of the patients in the trastuzumab deruxtecan group and in 1.9% of those in the trastuzumab emtansine group; none of these events were of grade 4 or 5. CONCLUSIONS: Among patients with HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane, the risk of disease progression or death was lower among those who received trastuzumab deruxtecan than among those who received trastuzumab emtansine. Treatment with trastuzumab deruxtecan was associated with interstitial lung disease and pneumonitis. (Funded by Daiichi Sankyo and AstraZeneca; DESTINY-Breast03 ClinicalTrials.gov number, NCT03529110.).

Trastuzumab deruxtecan versus trastuzumab emtansine in patients with HER2-positive metastatic breast cancer: updated results from DESTINY-Breast03, a randomised, open-label, phase 3 trial.

BACKGROUND: An improvement in progression-free survival was shown with trastuzumab deruxtecan versus trastuzumab emtansine in patients with HER2-positive metastatic breast cancer in the progression-free survival interim analysis of the DESTINY-Breast03 trial. The aim of DESTINY-Breast03 was to compare the efficacy and safety of trastuzumab deruxtecan versus trastuzumab emtansine. METHODS: This open-label, randomised, multicentre, phase 3 trial was done in 169 study centres in North America, Asia, Europe, Australia, and South America. Eligible patients were aged 18 or older, had HER2-positive unresectable or metastatic breast cancer previously treated with trastuzumab and a taxane, had an Eastern Cooperative Oncology Group performance status 0-1, and at least one measurable lesion per Response Evaluation Criteria in Solid Tumours version 1.1. Patients were randomly assigned (1:1) to receive trastuzumab deruxtecan 5·4 mg/kg or trastuzumab emtansine 3·6 mg/kg, both administered by intravenous infusion every 3 weeks. Randomisation was stratified by hormone receptor status, previous treatment with pertuzumab, and history of visceral disease, and was managed through an interactive web-based system. Within each stratum, balanced block randomisation was used with a block size of four. Patients and investigators were not masked to the treatment received. The primary endpoint was progression-free survival by blinded independent central review. The key secondary endpoint was overall survival and this prespecified second overall survival interim analysis reports updated overall survival, efficacy, and safety results. Efficacy analyses were performed using the full analysis set. Safety analyses included all randomly assigned patients who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT03529110. FINDINGS: Between July 20, 2018, and June 23, 2020, 699 patients were screened for eligibility, 524 of whom were enrolled and randomly assigned to receive trastuzumab deruxtecan (n=261) or trastuzumab emtansine (n=263). Median duration of study follow-up was 28·4 months (IQR 22·1-32·9) with trastuzumab deruxtecan and 26·5 months (14·5-31·3) with trastuzumab emtansine. Median progression-free survival by blinded independent central review was 28·8 months (95% CI 22·4-37·9) with trastuzumab deruxtecan and 6·8 months (5·6-8·2) with trastuzumab emtansine (hazard ratio [HR] 0·33 [95% CI 0·26-0·43]; nominal p<0·0001). Median overall survival was not reached (95% CI 40·5 months-not estimable), with 72 (28%) overall survival events, in the trastuzumab deruxtecan group and was not reached (34·0 months-not estimable), with 97 (37%) overall survival events, in the trastuzumab emtansine group (HR 0·64; 95% CI 0·47-0·87]; p=0·0037). The number of grade 3 or worse treatment-emergent adverse events was similar in patients who received trastuzumab deruxtecan versus trastuzumab emtansine (145 [56%] patients versus 135 [52%] patients). Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 39 (15%) patients treated with trastuzumab deruxtecan and eight (3%) patients treated with trastuzumab emtansine, with no grade 4 or 5 events in either group. INTERPRETATION: Trastuzumab deruxtecan showed a significant improvement in overall survival versus trastuzumab emtansine in patients with HER2-positive metastatic breast cancer, as well as the longest reported median progression-free survival, reaffirming trastuzumab deruxtecan as the standard of care in the second-line setting. A manageable safety profile of trastuzumab deruxtecan was confirmed with longer treatment duration. FUNDING: Daiichi Sankyo and AstraZeneca.

Sacituzumab Govitecan in Metastatic Triple-Negative Breast Cancer.

BACKGROUND: Patients with metastatic triple-negative breast cancer have a poor prognosis. Sacituzumab govitecan is an antibody-drug conjugate composed of an antibody targeting the human trophoblast cell-surface antigen 2 (Trop-2), which is expressed in the majority of breast cancers, coupled to SN-38 (topoisomerase I inhibitor) through a proprietary hydrolyzable linker. METHODS: In this randomized, phase 3 trial, we evaluated sacituzumab govitecan as compared with single-agent chemotherapy of the physician's choice (eribulin, vinorelbine, capecitabine, or gemcitabine) in patients with relapsed or refractory metastatic triple-negative breast cancer. The primary end point was progression-free survival (as determined by blinded independent central review) among patients without brain metastases. RESULTS: A total of 468 patients without brain metastases were randomly assigned to receive sacituzumab govitecan (235 patients) or chemotherapy (233 patients). The median age was 54 years; all the patients had previous use of taxanes. The median progression-free survival was 5.6 months (95% confidence interval [CI], 4.3 to 6.3; 166 events) with sacituzumab govitecan and 1.7 months (95% CI, 1.5 to 2.6; 150 events) with chemotherapy (hazard ratio for disease progression or death, 0.41; 95% CI, 0.32 to 0.52; P<0.001). The median overall survival was 12.1 months (95% CI, 10.7 to 14.0) with sacituzumab govitecan and 6.7 months (95% CI, 5.8 to 7.7) with chemotherapy (hazard ratio for death, 0.48; 95% CI, 0.38 to 0.59; P<0.001). The percentage of patients with an objective response was 35% with sacituzumab govitecan and 5% with chemotherapy. The incidences of key treatment-related adverse events of grade 3 or higher were neutropenia (51% with sacituzumab govitecan and 33% with chemotherapy), leukopenia (10% and 5%), diarrhea (10% and <1%), anemia (8% and 5%), and febrile neutropenia (6% and 2%). There were three deaths owing to adverse events in each group; no deaths were considered to be related to sacituzumab govitecan treatment. CONCLUSIONS: Progression-free and overall survival were significantly longer with sacituzumab govitecan than with single-agent chemotherapy among patients with metastatic triple-negative breast cancer. Myelosuppression and diarrhea were more frequent with sacituzumab govitecan. (Funded by Immunomedics; ASCENT ClinicalTrials.gov number, NCT02574455; EudraCT number, 2017-003019-21.).

Type I interferons, inflammation, and fatigue in a longitudinal RNA study of women with breast cancer.

BACKGROUND: Fatigue is a common side effect of cancer and its treatment and is thought to be driven in part by activation of the proinflammatory cytokine network. However, the cellular and molecular underpinnings of cancer-related fatigue (CRF) have not been determined, nor have immune pathways beyond inflammation been carefully investigated. The goal of this study was to examine the association between CRF and activation of canonical proinflammatory gene regulation pathways and Type I interferon (IFN) signaling pathways in breast cancer patients during and after treatment. METHODS: Women diagnosed with early-stage breast cancer (n = 181) completed assessments before and after treatment with radiation and/or chemotherapy and at 6, 12, and 18-month post-treatment follow-ups. Assessments included self-reported fatigue (Multidimensional Fatigue Symptom Inventory - Short Form) and expression of pre-specified sets of Type I IFN and pro-inflammatory immune response genes determined from mRNA sequencing of PBMCs. Mixed effect linear models examined changes in fatigue and immune gene expression over time and tested the hypothesis that fatigue would be associated with increased expression of Type I IFN and inflammatory response genes. RESULTS: There were significant changes in fatigue and immune gene expression across the assessment period; all measures increased from pre- to post-treatment but showed diverging patterns over the follow-up, with declines in fatigue and persistent elevations in Type I IFN and proinflammatory gene expression. In mixed effect linear models, expression of Type I IFN response genes was elevated in association with fatigue across the assessment period, from pre-treatment to 18-month follow-up. In contrast, pro-inflammatory gene expression was associated with fatigue only at 6, 12, and 18-month follow-ups. Analyses controlling for changes in leukocyte subsets continued to show a significant association between fatigue and Type I IFN gene expression but reduced the time-dependent association with pro-inflammatory gene expression to non-significant. CONCLUSIONS: Results revealed unexpected complexity in the immune underpinnings of CRF and identify a novel role for IFN signaling as a robust contributor to this symptom before, during, and after treatment. Pro-inflammatory gene expression emerged as a predictor of fatigue later in the cancer trajectory, and that effect was primarily accounted for by a concurrent increase in monocyte prevalence.

Neoadjuvant palbociclib plus either giredestrant or anastrozole in oestrogen receptor-positive, HER2-negative, early breast cancer (coopERA Breast Cancer): an open-label, randomised, controlled, phase 2 study.

BACKGROUND: The development of more potent selective oestrogen receptor antagonists and degraders (SERDs) that can be orally administered could help to address the limitations of current endocrine therapies. We report the primary and final analyses of the coopERA Breast Cancer study, designed to test whether giredestrant, a highly potent, non-steroidal, oral SERD, would show a stronger anti-proliferative effect than anastrozole after 2 weeks for oestrogen receptor-positive, HER2-negative, untreated early breast cancer. METHODS: In this open-label, randomised, controlled, phase 2 study, postmenopausal women were eligible if they were aged 18 years or older; had clinical T stage (cT)1c to cT4a-c (≥1·5 cm within cT1c) oestrogen receptor-positive, HER2-negative, untreated early breast cancer; an Eastern Cooperative Oncology Group performance status of 0-1; and baseline Ki67 score of at least 5%. The study was conducted at 59 hospital or clinic sites in 11 countries globally. Participants were randomly assigned (1:1) to giredestrant 30 mg oral daily or anastrozole 1 mg oral daily on days 1-14 (window-of-opportunity phase) via an interactive web-based system with permuted-block randomisation with block size of four. Randomisation was stratified by cT stage, baseline Ki67 score, and progesterone receptor status. A 16-week neoadjuvant phase comprised the same regimen plus palbociclib 125 mg oral daily on days 1-21 of a 28-day cycle, for four cycles. The primary endpoint was geometric mean relative Ki67 score change from baseline to week 2 in patients with complete central Ki67 scores at baseline and week 2 (window-of-opportunity phase). Safety was assessed in all patients who received at least one dose of study drug. The study is registered with ClinicalTrials.gov (NCT04436744) and is complete. FINDINGS: Between Sept 4, 2020, and June 22, 2021, 221 patients were enrolled and randomly assigned to the giredestrant plus palbociclib group (n=112; median age 62·0 years [IQR 57·0-68·5]) or anastrozole plus palbociclib group (n=109; median age 62·0 [57·0-67·0] years). 15 (7%) of 221 patients were Asian, three (1%) were Black or African American, 194 (88%) were White, and nine (4%) were unknown races. At data cutoff for the primary analysis (July 19, 2021), the geometric mean relative reduction of Ki67 from baseline to week 2 was -75% (95% CI -80 to -70) with giredestrant and -67% (-73 to -59) with anastrozole (p=0·043), meeting the primary endpoint. At the final analysis (data cutoff Nov 24, 2021), the most common grade 3-4 adverse events were neutropenia (29 [26%] of 112 in the giredestrant plus palbociclib group vs 29 [27%] of 109 in the anastrozole plus palbociclib group) and decreased neutrophil count (17 [15%] vs 16 [15%]). Serious adverse events occurred in five (4%) patients in the giredestrant plus palbociclib group and in two (2%) patients in the anastrozole plus palbociclib group. There were no treatment-related deaths. One patient died due to an adverse event in the giredestrant plus palbociclib group (myocardial infarction). INTERPRETATION: Giredestrant offers encouraging anti-proliferative and anti-tumour activity and was well tolerated, both as a single agent and in combination with palbociclib. Results justify further investigation in ongoing trials. FUNDING: F Hoffmann-La Roche.

Tumor biomarkers and efficacy in patients treated with trastuzumab emtansine + pertuzumab versus standard of care in HER2-positive early breast cancer: an open-label, phase III study (KRISTINE).

BACKGROUND: KRISTINE is an open-label, phase III study of trastuzumab emtansine + pertuzumab (T-DM1 + P) versus docetaxel + carboplatin + trastuzumab + pertuzumab (TCH + P) in patients with HER2-positive, stage II-III breast cancer. We investigated the association of biomarkers with clinical outcomes in KRISTINE. METHODS: Patients were randomized to receive neoadjuvant T-DM1 + P or TCH + P and assessed for pathologic complete response (pCR; ypT0/is, ypN0). HER2 status (per central assessment), hormone receptor status, PIK3CA mutation status, HER2/HER3 mRNA levels, tumor-infiltrating lymphocyte levels, PD-L1 status, and NanoString data were analyzed. pCR rates by treatment arm were compared across biomarker subgroups. Analyses were descriptive. RESULTS: Biomarker analyses included data from all 444 patients (T-DM1 + P, n = 223; TCH + P, n = 221) enrolled in KRISTINE. Biomarker distribution was balanced across treatment arms. All subgroups with higher HER2 amplification/expression and immune marker levels showed numerically higher pCR rates in both arms. Mutated versus non-mutated PIK3CA tumors were associated with numerically lower pCR rates in the T-DM1 + P arm but not in the TCH + P arm. In a multivariate analysis, Prediction Analysis of Microarray with the 50-gene classifier (PAM50) HER2-enriched subtype, HER2 gene ratio ≥ 4, and PD-L1-positive status positively influenced the pCR rate. Biomarkers associated with lower pCR rates (e.g., low HER2 levels, positive hormone receptor status, mutated PIK3CA) were more likely to co-occur. Dynamic on-treatment biomarker changes were observed. Differences in the treatment effects for T-DM1 + P versus TCH + P were similar to those observed in the intent-to-treat population for the majority of the biomarker subgroups. CONCLUSIONS: Although our biomarker analysis did not identify a subgroup of patients that benefited from neoadjuvant T-DM1 + P versus TCH + P, the data revealed that patients with higher HER2 amplification/expression and immune marker levels had improved response irrespective of treatment arm. These analyses confirm the role of HER2 tumor biology and the immune microenvironment in influencing pCR in the neoadjuvant setting and reaffirm the molecular diversity of HER2-positive breast cancer. TRIAL REGISTRATION: ClinicalTrials.gov NCT02131064. Registered 06 May 2014.

Trastuzumab Deruxtecan in Previously Treated HER2-Positive Breast Cancer.

BACKGROUND: Trastuzumab deruxtecan (DS-8201) is an antibody-drug conjugate composed of an anti-HER2 (human epidermal growth factor receptor 2) antibody, a cleavable tetrapeptide-based linker, and a cytotoxic topoisomerase I inhibitor. In a phase 1 dose-finding study, a majority of the patients with advanced HER2-positive breast cancer had a response to trastuzumab deruxtecan (median response duration, 20.7 months). The efficacy of trastuzumab deruxtecan in patients with HER2-positive metastatic breast cancer previously treated with trastuzumab emtansine requires confirmation. METHODS: In this two-part, open-label, single-group, multicenter, phase 2 study, we evaluated trastuzumab deruxtecan in adults with pathologically documented HER2-positive metastatic breast cancer who had received previous treatment with trastuzumab emtansine. In the first part of the study, we evaluated three different doses of trastuzumab deruxtecan to establish a recommended dose; in the second part, we evaluated the efficacy and safety of the recommended dose. The primary end point was the objective response, according to independent central review. Key secondary end points were the disease-control rate, clinical-benefit rate, duration of response and progression-free survival, and safety. RESULTS: Overall, 184 patients who had undergone a median of six previous treatments received the recommended dose of trastuzumab deruxtecan (5.4 mg per kilogram of body weight). In the intention-to-treat analysis, a response to therapy was reported in 112 patients (60.9%; 95% confidence interval [CI], 53.4 to 68.0). The median duration of follow-up was 11.1 months (range, 0.7 to 19.9). The median response duration was 14.8 months (95% CI, 13.8 to 16.9), and the median duration of progression-free survival was 16.4 months (95% CI, 12.7 to not reached). During the study, the most common adverse events of grade 3 or higher were a decreased neutrophil count (in 20.7% of the patients), anemia (in 8.7%), and nausea (in 7.6%). On independent adjudication, the trial drug was associated with interstitial lung disease in 13.6% of the patients (grade 1 or 2, 10.9%; grade 3 or 4, 0.5%; and grade 5, 2.2%). CONCLUSIONS: Trastuzumab deruxtecan showed durable antitumor activity in a pretreated patient population with HER2-positive metastatic breast cancer. In addition to nausea and myelosuppression, interstitial lung disease was observed in a subgroup of patients and requires attention to pulmonary symptoms and careful monitoring. (Funded by Daiichi Sankyo and AstraZeneca; DESTINY-Breast01 ClinicalTrials.gov number, NCT03248492.).

Tucatinib, Trastuzumab, and Capecitabine for HER2-Positive Metastatic Breast Cancer.

BACKGROUND: Patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer who have disease progression after therapy with multiple HER2-targeted agents have limited treatment options. Tucatinib is an investigational, oral, highly selective inhibitor of the HER2 tyrosine kinase. METHODS: We randomly assigned patients with HER2-positive metastatic breast cancer previously treated with trastuzumab, pertuzumab, and trastuzumab emtansine, who had or did not have brain metastases, to receive either tucatinib or placebo, in combination with trastuzumab and capecitabine. The primary end point was progression-free survival among the first 480 patients who underwent randomization. Secondary end points, assessed in the total population (612 patients), included overall survival, progression-free survival among patients with brain metastases, confirmed objective response rate, and safety. RESULTS: Progression-free survival at 1 year was 33.1% in the tucatinib-combination group and 12.3% in the placebo-combination group (hazard ratio for disease progression or death, 0.54; 95% confidence interval [CI], 0.42 to 0.71; P<0.001), and the median duration of progression-free survival was 7.8 months and 5.6 months, respectively. Overall survival at 2 years was 44.9% in the tucatinib-combination group and 26.6% in the placebo-combination group (hazard ratio for death, 0.66; 95% CI, 0.50 to 0.88; P = 0.005), and the median overall survival was 21.9 months and 17.4 months, respectively. Among the patients with brain metastases, progression-free survival at 1 year was 24.9% in the tucatinib-combination group and 0% in the placebo-combination group (hazard ratio, 0.48; 95% CI, 0.34 to 0.69; P<0.001), and the median progression-free survival was 7.6 months and 5.4 months, respectively. Common adverse events in the tucatinib group included diarrhea, palmar-plantar erythrodysesthesia syndrome, nausea, fatigue, and vomiting. Diarrhea and elevated aminotransferase levels of grade 3 or higher were more common in the tucatinib-combination group than in the placebo-combination group. CONCLUSIONS: In heavily pretreated patients with HER2-positive metastatic breast cancer, including those with brain metastases, adding tucatinib to trastuzumab and capecitabine resulted in better progression-free survival and overall survival outcomes than adding placebo; the risks of diarrhea and elevated aminotransferase levels were higher with tucatinib. (Funded by Seattle Genetics; HER2CLIMB ClinicalTrials.gov number, NCT02614794.).

NCCN Guidelines® Insights: Breast Cancer, Version 4.2023.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Breast Cancer address all aspects of management for breast cancer. The treatment landscape of metastatic breast cancer is evolving constantly. The therapeutic strategy takes into consideration tumor biology, biomarkers, and other clinical factors. Due to the growing number of treatment options, if one option fails, there is usually another line of therapy available, providing meaningful improvements in survival. This NCCN Guidelines Insights report focuses on recent updates specific to systemic therapy recommendations for patients with stage IV (M1) disease.

A look at current and potential treatment approaches for hormone receptor-positive, HER2-negative early breast cancer.

The heterogeneity of hormone receptor (HR)-positive, HER2-negative early breast cancers reinforces the importance of individualized, risk-adapted treatment approaches. Numerous factors contribute to the risk for recurrence, including clinical tumor features, individual biomarkers, and genomic risk. Current standard approaches for patients with HR-positive, HER2-negative, early stage disease focus on endocrine therapy and chemotherapy. The specific treatment regimen and duration of adjuvant therapy should be selected based on accurate risk assessment, tolerability of available therapies, and consideration for patient preferences. For patients with high-risk features, such as highly proliferative tumors, large tumor size, and significant nodal involvement, the risk for recurrence remains clinically significant despite appropriate adjuvant treatment with current standards of care. This has driven investigation into novel treatment approaches, including the addition of cyclin-dependent kinase 4 and 6 inhibitors to adjuvant endocrine therapy. Cyclin-dependent kinase 4 and 6 inhibition has demonstrated significant efficacy in patients with high-risk, HR-positive, HER2-negative, nonmetastatic breast cancer and now offers a new strategy to greatly improve outcomes in this difficult to treat patient population.; LAY SUMMARY: Hormone receptor (HR)-positive, HER2-negative early breast cancers are highly diverse and need to be managed differently for individual patients. The use of adjuvant endocrine therapy and chemotherapy should be driven by a patient's risk for recurrence, preferences, and risk for side effects. Patients with high-risk tumors have a persistently elevated risk for recurrence despite current standards of care. Emerging cyclin-dependent kinase 4 and 6 inhibitors are highly effective when added to endocrine therapy in high-risk, HR-positive early breast cancer and have the potential to improve patient outcomes in this difficult to treat patient population.

Overall Survival with Ribociclib plus Endocrine Therapy in Breast Cancer.

BACKGROUND: An earlier analysis of this phase 3 trial showed that the addition of a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor to endocrine therapy provided a greater benefit with regard to progression-free survival than endocrine therapy alone in premenopausal or perimenopausal patients with advanced hormone-receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer. Here we report the results of a protocol-specified interim analysis of the key secondary end point of overall survival. METHODS: We randomly assigned patients to receive either ribociclib or placebo in addition to endocrine therapy (goserelin and either a nonsteroidal aromatase inhibitor or tamoxifen). Overall survival was evaluated with the use of a stratified log-rank test and summarized with the use of Kaplan-Meier methods. RESULTS: A total of 672 patients were included in the intention-to-treat population. There were 83 deaths among 335 patients (24.8%) in the ribociclib group and 109 deaths among 337 patients (32.3%) in the placebo group. The addition of ribociclib to endocrine therapy resulted in significantly longer overall survival than endocrine therapy alone. The estimated overall survival at 42 months was 70.2% (95% confidence interval [CI], 63.5 to 76.0) in the ribociclib group and 46.0% (95% CI, 32.0 to 58.9) in the placebo group (hazard ratio for death, 0.71; 95% CI, 0.54 to 0.95; P = 0.00973 by log-rank test). The survival benefit seen in the subgroup of 495 patients who received an aromatase inhibitor was consistent with that in the overall intention-to-treat population (hazard ratio for death, 0.70; 95% CI, 0.50 to 0.98). The percentage of patients who received subsequent antineoplastic therapy was balanced between the groups (68.9% in the ribociclib group and 73.2% in the placebo group). The time from randomization to disease progression during receipt of second-line therapy or to death was also longer in the ribociclib group than in the placebo group (hazard ratio for disease progression or death, 0.69; 95% CI, 0.55 to 0.87). CONCLUSIONS: This trial showed significantly longer overall survival with a CDK4/6 inhibitor plus endocrine therapy than with endocrine therapy alone among patients with advanced hormone-receptor-positive, HER2-negative breast cancer. No new concerns regarding toxic effects emerged with longer follow-up. (Funded by Novartis; MONALEESA-7 ClinicalTrials.gov number, NCT02278120.).

Analysis of patients without and with an initial triple-negative breast cancer diagnosis in the phase 3 randomized ASCENT study of sacituzumab govitecan in metastatic triple-negative breast cancer.

PURPOSE: Sacituzumab govitecan (SG) is an antibody-drug conjugate composed of an anti-Trop-2 antibody coupled to SN-38 via a proprietary hydrolyzable linker. In the ASCENT study, SG improved survival versus single-agent treatment of physician's choice (TPC) in pre-treated metastatic triple-negative breast cancer (mTNBC). Hormone/HER2 receptor changes are common, particularly at relapse/metastasis. This subanalysis assessed outcomes in patients who did/did not have TNBC at initial diagnosis, before enrollment. METHODS: TNBC diagnosis was only required at study entry. Patients with mTNBC refractory/relapsing after ≥ 2 prior chemotherapies were randomized 1:1 to receive SG or TPC. Primary endpoint was progression-free survival (PFS) in patients without brain metastases. RESULTS: Overall, 70/235 (30%) and 76/233 (33%) patients who received SG and TPC, respectively, did not have TNBC at initial diagnosis. Clinical benefit with SG versus TPC was observed in this subset. Median PFS was 4.6 versus 2.3 months (HR 0.48; 95% CI 0.32-0.72), median overall survival was 12.4 versus 6.7 months (HR 0.44; 95% CI 0.30-0.64), and objective response rate (ORR) was 31% versus 4%; those who also received prior CDK4/6 inhibitors had ORRs of 21% versus 5%. Efficacy and safety for patients with TNBC at initial diagnosis were generally similar to those who did not present with TNBC at initial diagnosis. CONCLUSION: Patients without TNBC at initial diagnosis had improved clinical outcomes and a manageable safety profile with SG, supporting SG as a treatment option for mTNBC regardless of subtype at initial diagnosis. Subtype reassessment in advanced breast cancer allows for optimal treatment. Clinical trial registration number NCT02574455, registered October 12, 2015.

Breast Cancer, Version 3.2022, NCCN Clinical Practice Guidelines in Oncology.

The therapeutic options for patients with noninvasive or invasive breast cancer are complex and varied. These NCCN Clinical Practice Guidelines for Breast Cancer include recommendations for clinical management of patients with carcinoma in situ, invasive breast cancer, Paget disease, phyllodes tumor, inflammatory breast cancer, and management of breast cancer during pregnancy. The content featured in this issue focuses on the recommendations for overall management of ductal carcinoma in situ and the workup and locoregional management of early stage invasive breast cancer. For the full version of the NCCN Guidelines for Breast Cancer, visit NCCN.org.

ASTEFANIA: adjuvant ado-trastuzumab emtansine and atezolizumab for high-risk, HER2-positive breast cancer.

There is a strong rationale for combining HER2-targeted therapies with cancer immunotherapy to increase efficacy in breast cancer, particularly in the early-stage setting, where the immune system has not been weakened by heavy pretreatment. ASTEFANIA aims to evaluate the efficacy of adjuvant atezolizumab in combination with ado-trastuzumab emtansine in patients with high-risk, HER2-positive early breast cancer and residual disease following HER2-based neoadjuvant therapy. Eligible patients will be randomized to receive ado-trastuzumab emtansine in combination with either atezolizumab or placebo for 14 cycles within 12 weeks of primary surgery. The primary outcome is invasive disease-free survival and secondary outcomes include additional efficacy end points, safety and pharmacokinetics. The study plans to enroll 1700 patients across 32 counties. Clinical Trial Registration: NCT04873362 (ClinicalTrials.gov).

Do all patients with cancer experience fatigue? A longitudinal study of fatigue trajectories in women with breast cancer.

BACKGROUND: Fatigue is a common and expected side effect of cancer treatment. However, the majority of studies to date have focused on average levels of fatigue, which may obscure important individual differences in the severity and course of fatigue over time. The current study was designed to identify distinct trajectories of fatigue from diagnosis into survivorship in a longitudinal study of women with early-stage breast cancer. METHODS: Women with stage 0 to stage IIIA breast cancer (270 women) were recruited before (neo)adjuvant therapy with radiotherapy, chemotherapy, and/or endocrine therapy and completed assessments at baseline; posttreatment; and at 6 months, 12 months, and 18 months of follow-up. Growth mixture modeling was used to identify trajectories of fatigue, and differences among the trajectory groups with regard to demographic, medical, and psychosocial variables were examined. RESULTS: Five distinct trajectories of fatigue were identified: Stable Low (66%), with low levels of fatigue across assessments; Stable High (13%), with high fatigue across assessments; Decreasing (4%), with high fatigue at baseline that resolved over time; Increasing (9%), with low fatigue at baseline that increased over time; and Reactive (8%), with increased fatigue after treatment that resolved over time. Both psychological and treatment-related factors were found to be associated with fatigue trajectories, with psychological factors most strongly linked to high fatigue at the beginning of and over the course of treatment. CONCLUSIONS: There is considerable variability in the experience of fatigue among women with early-stage breast cancer. Although the majority of women report relatively low fatigue, those with a history of depression and elevated psychological distress may be at risk of more severe and persistent fatigue.

Efficacy of Neratinib Plus Capecitabine in the Subgroup of Patients with Central Nervous System Involvement from the NALA Trial.

BACKGROUND: Neratinib has efficacy in central nervous system (CNS) metastases from HER2-positive metastatic breast cancer (MBC). We report outcomes among patients with CNS metastases at baseline from the phase III NALA trial of neratinib plus capecitabine (N + C) versus lapatinib plus capecitabine (L + C). MATERIALS AND METHODS: NALA was a randomized, active-controlled trial in patients who received two or more previous HER2-directed regimens for HER2-positive MBC. Patients with asymptomatic/stable brain metastases (treated or untreated) were eligible. Patients were assigned to N + C (neratinib 240 mg per day, capecitabine 750 mg/m2 twice daily) or L + C (lapatinib 1,250 mg per day, capecitabine 1,000 mg/m2 twice daily) orally. Independently adjudicated progression-free survival (PFS), overall survival (OS), and CNS endpoints were considered. RESULTS: Of 621 patients enrolled, 101 (16.3%) had known CNS metastases at baseline (N + C, n = 51; L + C, n = 50); 81 had received prior CNS-directed radiotherapy and/or surgery. In the CNS subgroup, mean PFS through 24 months was 7.8 months with N + C versus 5.5 months with L + C (hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.41-1.05), and mean OS through 48 months was 16.4 versus 15.4 months (HR, 0.90; 95% CI, 0.59-1.38). At 12 months, cumulative incidence of interventions for CNS disease was 25.5% for N + C versus 36.0% for L + C, and cumulative incidence of progressive CNS disease was 26.2% versus 41.6%, respectively. In patients with target CNS lesions at baseline (n = 32), confirmed intracranial objective response rates were 26.3% and 15.4%, respectively. No new safety signals were observed. CONCLUSION: These analyses suggest improved PFS and CNS outcomes with N + C versus L + C in patients with CNS metastases from HER2-positive MBC. IMPLICATIONS FOR PRACTICE: In a subgroup of patients with central nervous system (CNS) metastases from HER2-positive breast cancer after two or more previous HER2-directed regimens, the combination of neratinib plus capecitabine was associated with improved progression-free survival and CNS outcomes compared with lapatinib plus capecitabine. These findings build on previous phase II and III studies describing efficacy of neratinib in the prevention and treatment of CNS metastases, and support a role for neratinib as a systemic treatment option in the management of patients with HER2-positive brain metastases following antibody-based HER2-directed therapies.

Talazoparib in Patients with Advanced Breast Cancer and a Germline BRCA Mutation.

BACKGROUND: The poly(adenosine diphosphate-ribose) inhibitor talazoparib has shown antitumor activity in patients with advanced breast cancer and germline mutations in BRCA1 and BRCA2 ( BRCA1/2). METHODS: We conducted a randomized, open-label, phase 3 trial in which patients with advanced breast cancer and a germline BRCA1/2 mutation were assigned, in a 2:1 ratio, to receive talazoparib (1 mg once daily) or standard single-agent therapy of the physician's choice (capecitabine, eribulin, gemcitabine, or vinorelbine in continuous 21-day cycles). The primary end point was progression-free survival, which was assessed by blinded independent central review. RESULTS: Of the 431 patients who underwent randomization, 287 were assigned to receive talazoparib and 144 were assigned to receive standard therapy. Median progression-free survival was significantly longer in the talazoparib group than in the standard-therapy group (8.6 months vs. 5.6 months; hazard ratio for disease progression or death, 0.54; 95% confidence interval [CI], 0.41 to 0.71; P<0.001). The interim median hazard ratio for death was 0.76 (95% CI, 0.55 to 1.06; P=0.11 [57% of projected events]). The objective response rate was higher in the talazoparib group than in the standard-therapy group (62.6% vs. 27.2%; odds ratio, 5.0; 95% CI, 2.9 to 8.8; P<0.001). Hematologic grade 3-4 adverse events (primarily anemia) occurred in 55% of the patients who received talazoparib and in 38% of the patients who received standard therapy; nonhematologic grade 3 adverse events occurred in 32% and 38% of the patients, respectively. Patient-reported outcomes favored talazoparib; significant overall improvements and significant delays in the time to clinically meaningful deterioration according to both the global health status-quality-of-life and breast symptoms scales were observed. CONCLUSIONS: Among patients with advanced breast cancer and a germline BRCA1/2 mutation, single-agent talazoparib provided a significant benefit over standard chemotherapy with respect to progression-free survival. Patient-reported outcomes were superior with talazoparib. (Funded by Medivation [Pfizer]; EMBRACA ClinicalTrials.gov number, NCT01945775 .).

Systematic review and meta-analysis of febrile neutropenia risk with TCH(P) in HER2-positive breast cancer.

BACKGROUND: Docetaxel, carboplatin and trastuzumab, with or without pertuzumab (TCH(P)), has become the preferred (neo)adjuvant regimen for HER2-positive breast cancer. However, its associated febrile neutropenia (FN) risk is unclear: pivotal studies reported FN risks < 10%, but in clinical practice, a high FN rate (> 20%) was observed. This systematic review and meta-analysis determine the FN risk associated with TCH(P) and the indication for primary prophylactic granulocyte colony-stimulating factor (PP G-CSF). METHODS: The MEDLINE, Embase, Web of Science and Cochrane databases were searched for full-text English articles reporting the FN incidence in early breast cancer patients receiving (neo)adjuvant TCH(P). The primary endpoint was the pooled crude FN incidence in patients treated without PP G-CSF using the random effects method. Secondary endpoints were the FN risk with PP G-CSF support, age-related differences in FN and differences in risk with TCH versus TCHP. RESULTS: Seventeen studies were included in the systematic review. The pooled estimates of FN incidences were 27.6% (95% CI 18.6 to 37.1) in patients who did not receive PP G-CSF (primary meta-analysis, 9 studies, n = 889) versus 5.0% (95% CI 2.6 to 8.0) in patients administered PP G-CSF (secondary meta-analysis, 7 studies, n = 445). Two studies reported non-significant age-related differences in FN. The risk comparison between TCH and TCHP was inconclusive. CONCLUSIONS: The crude FN risk associated with (neo)adjuvant TCH(P) is over 20%, the upper limit above which the international guidelines unanimously advise PP G-CSF administration. G-CSF prophylaxis effectively reduces FN risk and should become the standard of care with (neo)adjuvant TCH(P).