Factor Receptor 2-negative Breast Cancer Research Articles

The role of adjuvant endocrine treatment in ER+, PR−, HER2− early breast cancer: a retrospective study of real-world data

Purpose: Estrogen receptor-positive (ER+), progesterone receptor-negative (PR-) and human epidermal growth factor receptor 2-negative (HER2−) breast cancer (BC) often developed resistance to endocrine treatment (ET). We aimed to explore (1) the different clinicopathological features between ER+/PR+/HER2- and ER+/PR-/HER2- BC, and (2) whether ER+/PR-/HER2- early BC patients could benefit from adjuvant ET. Methods: All patients treated for ER+/HER2- early BC who underwent surgery between 2010 and 2021 from a BC database in China were retrospectively examined. The cases followed up for less than six months were excluded. Results: The records of ER+/PR+/HER2- (n = 10843) and ER+/PR-/HER2- BC (n = 1193) cases were reviewed, with median follow-up times of 35.8 and 47.0 months, respectively. Compared with ER+/PR+/HER2- cases, ER+/PR-/HER2- BC occurred more in postmenopausal women (73.1% vs. 52.9%, p = 0.000) and were more likely to be T > 2 cm (40.6% vs. 37.6%, p = 0.048) and Ki67 > 20%+ (48.1% vs. 36.9%, p = 0.000). However, ER+/PR-/HER2- cases had fewer nodal involvement (32.9% vs. 36.9%, p = 0.000). Approximately 82.2% (981/1193) of ER+/PR-/HER2- patients received ET, while approximately 17.8% (212/1193) did not. Compared to patients did not receive adjuvant ET, the ET group had similar disease-free survival (DFS) (HR = 1.33, 95% confidence interval (CI): 0.68–2.59, p = 0.444) and overall survival (OS) (HR = 1.17, 95%CI: 0.37–3.68, p = 0.799). 65.7% of recurrent ER+/PR-/HER2- patients experienced distant relapse (65.7% vs. 48.2% (for ER+/PR + cases), p = 0.011). By comparison, recurrent ER+/PR+/HER2- patients were more likely to experience only local relapse (31.6% vs. 14.9% (for ER+/PR- cases), p = 0.007). Conclusions: ER+/PR-/HER2- BC was a special subtype with aggressive clinicopathological features and more tend to have distant metastasis rather than nodal involvement or local relapse. ER+/PR-/HER2- early BC did not seem to benefit from adjuvant ET.

Predictive Value of Immune Activity Changes in Breast Cancer Patients Treated With Dose-dense Neoadjuvant Chemotherapy: A Retrospective Study.

Dose-dense chemotherapy is recommended for patients with breast cancer who have a high recurrence risk. However, whether dose-dense neoadjuvant chemotherapy (ddNAC) improves patient prognoses compared to the normal-dose regimen remains controversial. In this study, we evaluated the predictive value of immune activities on short-term outcomes for patients treated with ddNAC. We classified 82 patients with human epidermal growth factor receptor 2-negative breast cancer treated with NAC into a normal dose group (62 patients) and ddNAC group (20 patients) and examined the differences in clinicopathological features. The ddNAC group was further divided according to patient responses to NAC and the predictive factors for pathological complete response (pCR) were evaluated. There were no differences in the clinicopathological features before NAC between the normal dose and ddNAC groups. Although the pCR rates tended to be higher in the ddNAC group compared than those in the normal dose group (35.0% vs. 25.8%), there was not significant difference (p=0.264). Among all patients treated with ddNAC, the absolute lymphocyte count decreased and the neutrophil-to-lymphocyte ratio increased during dose-dense doxorubicin plus cyclophosphamide treatment. There was no significant correlation between the pCR and any of the clinicopathological parameters tested including systemic peripheral markers and tumor-infiltrating lymphocyte levels. ddNAC affected the levels of systemic peripheral immune markers. However, monitoring these markers may not be useful for predicting responses to ddNAC.

Real-world effectiveness of palbociclib plus endocrine therapy in HR+/HER2- advanced breast cancer: final results from the POLARIS trial.

Strict eligibility criteria for participation in randomized clinical trials (RCTs) often limit the generalizability of data when applied to a more heterogeneous real-world population. Thus, evidence generated directly from real-world populations, including subgroups underrepresented in RCTs, can help inform routine clinical practice. POLARIS (NCT03280303), a prospective, observational, multicenter, cohort study, evaluated patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer (ABC) receiving palbociclib + endocrine therapy (ET) in routine care. Demographics, baseline characteristics, and treatment patterns were summarized descriptively. Real-world response and clinical benefit rates, real-world progression-free survival (rwPFS), and overall survival (OS) were summarized descriptively by line of therapy and endocrine partner in the overall cohort and various subgroups. Between January 2017 and October 2019, 1250 patients (median age of 64.0 years) initiated treatment with palbociclib-based therapy, including 901 in the first-line (1L) setting and 349 in the second-line or later (≥2L) settings. Real-world response and clinical benefit rates with palbociclib + ET were 34.0% and 69.4%, respectively, in 1L, and 21.8% and 57.9% in ≥2L. Median rwPFS was 20.9 (95% CI, 18.7-24.7) and 13.5 (10.6-17.1) months, and median OS was 48.5 (42.0-not estimable) and 37.2 (31.2-40.8) months, with 1L and ≥2L palbociclib + ET, respectively. Outcomes in this large, heterogeneous, real-world population are generally consistent with previously reported results from clinical trials and other real-world studies, further supporting the use of palbociclib + ET in patients with HR+/HER2- ABC. NCT03280303 (ClinicalTrials.gov).

Double-Faced Immunological Effects of CDK4/6 Inhibitors on Cancer Treatment: Challenges and Perspectives

Cyclin-dependent kinases (CDKs) are generally involved in the progression of cell cycle and cell division in normal cells, while abnormal activations of CDKs are deemed to be a driving force for accelerating cell proliferation and tumorigenesis. Therefore, CDKs have become ideal therapeutic targets for cancer treatment. The U.S FDA has approved three CDK4/6 inhibitors (CDK4/6is) for the treatment of patients with hormone receptor-positive (HR+) or human epidermal growth factor receptor 2-negative (HER2−) advanced or metastatic breast cancer, and these drugs showed impressive results in clinics. Besides cell-cycle arrest, there is growing evidence that CDK4/6is exert paradoxical roles on cancer treatment by altering the immune system. Indeed, clinical data showed that CDK4/6is could change the immune system to exert antitumor effects, while these changes also caused tumor resistance to CDK4/6i. However, the molecular mechanism for the regulation of the immune system by CDK4/6is is unclear. In this review, we comprehensively discuss the paradoxical immunological effects of CDK4/6is in cancer treatment, elucidating their anticancer mechanisms through immunomodulatory activity and induction of acquired drug resistance by dysregulating the immune microenvironment. More importantly, we suggest a few strategies including combining CDK4/6is with immunotherapy to overcome drug resistance.

Impact of extended endocrine therapy for patients with risk factors for late recurrence in estrogen receptor-positive, human epidermal growth factor receptor 2-negative breast cancer after 5years of endocrine therapy.

Extended endocrine therapy shows promise for reducing the recurrence of estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer. However, its benefits in patients with high-risk factors for late recurrence remain unclear, particularly in premenopausal patients. In this study, we aimed to explore the impact of extended endocrine therapy in patients with risk factors for late recurrence of postmenopausal and premenopausal ER-positive, HER2-negative breast cancer. We retrospectively analyzed data from patients with ER-positive, HER2-negative breast cancer at Tohoku Kosai Hospital who were disease-free after 5years of adjuvant endocrine therapy. The patients were classified as high risk based on lymph node positivity, tumor size > 2cm, or high tumor grade. The high-risk group was further divided into extended therapy and stop groups. Propensity score matching was applied to balance baseline characteristics. Disease-free survival (DFS) was the primary endpoint. Among the 1474 eligible patients, 224 received extended endocrine therapy, and 1250 stopped therapy. After propensity score matching, the high-risk group comprised 348 patients (n = 174 patients/group). The extended therapy group had significantly higher 10-year DFS and distant DFS rates than the stop group. The multivariate Cox model indicated a 69% reduction in recurrence risk in the extended therapy group. Extended endocrine therapy can substantially improve DFS in patients with high-risk ER-positive, HER2-negative breast cancer, especially in those with large tumors, lymph node involvement, and high tumor grade. These findings support personalized treatment strategies for enhancing long-term outcomes.

Palbociclib plus aromatase inhibitors in patients with metastatic breast cancer and cardiovascular diseases: real-world effectiveness.

Patients with cardiovascular disease (CVD) comorbidities are often excluded from participating in breast cancer clinical trials. Consequently, data to inform treatment decisions for patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast cancer (mBC) and CVD are limited. We compared the effectiveness of first-line palbociclib plus an aromatase inhibitor (AI) vs an AI alone and evaluated palbociclib treatment patterns in patients with HR+/HER2- mBC and CVD in routine clinical practice. Data from the Flatiron Health Analytic Database were captured for patients with HR+/HER2- mBC and CVD who initiated first-line treatment with palbociclib plus an AI or an AI alone between February 2015 and March 2020 (data cutoff: September 30, 2020). Overall survival (OS), real-world progression-free survival (PFS), and treatment patterns were evaluated. Of the 469 patients with identifiable CVD, 160 received palbociclib plus an AI, and 309 received an AI alone. After stabilized inverse probability treatment weighting, both median OS (40.7 vs 26.5 months; hazard ratio [HR], 0.732 [95% CI, 0.537-0.997]; P = .048) and median real-world PFS (20.0 vs 12.5 months; HR, 0.679 [95% CI, 0.512-0.900]; P = .007) were significantly prolonged in patients treated with palbociclib plus an AI vs an AI alone. Among patients with a documented palbociclib starting dose, 78.5% started palbociclib at 125mg/day, and 38.6% experienced dose adjustment. In this real-world analysis, first-line palbociclib plus an AI was associated with improved effectiveness compared with an AI alone in patients with HR+/HER2- mBC and CVD. NCT05361655 (ClinicalTrials.gov).

Capivasertib and fulvestrant for patients with HR-positive/HER2-negative advanced breast cancer: analysis of the subgroup of patients from Japan in the phase 3 CAPItello-291 trial.

In CAPItello-291, capivasertib-fulvestrant significantly improved progression-free survival (PFS) versus placebo-fulvestrant in the overall and PIK3CA/AKT1/PTEN-altered population with hormone receptor-positive (HR-positive)/human epidermal growth factor receptor 2-negative (HER2-negative) advanced breast cancer. Capivasertib-fulvestrant is approved in Japan for the treatment of patients with one or more tumor biomarker alterations (PIK3CA, AKT1 or PTEN). Here, we report outcomes in the CAPItello-291 subgroup of patients from Japan. Adults with HR-positive/HER2-negative advanced breast cancer whose disease had relapsed or progressed during or after treatment with an aromatase inhibitor, with or without previous cyclin-dependent kinase 4/6 (CDK4/6) inhibitor therapy, were randomly assigned (1:1 ratio) to receive capivasertib or placebo, plus fulvestrant. The dual primary endpoint was investigator-assessed PFS in the overall andPIK3CA/AKT1/PTEN-altered population. Safety was a secondary endpoint. Of 708 patients randomized in CAPItello-291, 78 were from Japan (37 randomized to capivasertib-fulvestrant and 41 to placebo-fulvestrant). In the Japan subgroup, PFS numerically favored the capivasertib-fulvestrant arm (hazard ratio 0.73; 95% CI 0.40-1.28), consistent with the analysis of PFS in the global population. Similarly, in the Japan subgroup of patients with PIK3CA/AKT1/PTEN-altered tumors, PFS favored the capivasertib-fulvestrant arm (hazard ratio 0.65; 95% CI 0.29-1.39), consistent with the global population. The adverse event profile of capivasertib-fulvestrant in the Japan subgroup was broadly similar to that in the global population; no new safety concerns were identified. Outcomes in the Japan subgroup were broadly similar to those of the global population, supporting the clinical benefit of capivasertib-fulvestrant in treating HR-positive/HER2-negative advanced breast cancer that has progressed on, or after, an endocrine-based regimen.

The Systemic Immune-Inflammation Index is a Predictor of Chemotherapy Sensitivity and Disease-Free Survival in Patients With Hormone Receptor-Positive Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer

BackgroundThe relationship between the systemic immune-inflammation index (SII), chemotherapy sensitivity, and prognosis in HR+HER2– breast cancer (BC) has not been extensively studied. Patients and methodsClinical data from 980 patients diagnosed with HR+HER2– BC between June 2012 and June 2016 were collected. Patients were divided into low- and high-SII groups according to median SII value. Differences among variables were assessed using the chi-squared test. The inverse probability of treatment weighting (IPTW) method was used to control bias. The associations between clinicopathological factors, baseline SII, and disease-free survival (DFS) were analyzed using Kaplan–Meier curves and Cox analyses. ResultsThe median follow-up period was 37 months (5-77). 480 patients underwent neoadjuvant chemotherapy, and low baseline SII values were associated with higher pathological complete response (pCR) rates than those in the high SII group (16.4% vs. 9.2%; P = .019). Multivariate analyses revealed that larger tumor size, more lymph node involvement, high Ki-67 score, and high baseline SII were independent prognostic factors for worse outcomes in patients with HR+HER2– BC. The risk for metastasis/recurrence was higher in the high SII group compared with that in the low SII group (hazard ratio 2.07 [95% CI, 1.35-3.19]; P = .001). After IPTW, a similar result was obtained, in that a high SII value was significantly associated with worse DFS among patients with HR+HER2– BC. ConclusionA low baseline SII was associated with higher pCR rates after neoadjuvant chemotherapy and was an independent prognostic factor for better DFS outcomes in patients with HR+HER2– BC.

Sacituzumab govitecan in HR+HER2- metastatic breast cancer: the randomized phase 3 EVER-132-002 trial.

Sacituzumab govitecan (SG) significantly improved progression-free survival (PFS) and overall survival (OS) versus chemotherapy in hormone receptor-positive human epidermal growth factor receptor 2-negative (HR+HER2-) metastatic breast cancer (mBC) in the global TROPiCS-02 study. TROPiCS-02 enrolled few Asian patients. Here we report results of SG in Asian patients with HR+HER2- mBC from the EVER-132-002 study. Patients were randomized to SG (n = 166) or chemotherapy (n = 165). The primary endpoint was met: PFS was improved with SG versus chemotherapy (hazard ratio of 0.67, 95% confidence interval 0.52-0.87; P = 0.0028; median 4.3 versus 4.2 months). OS also improved with SG versus chemotherapy (hazard ratio of 0.64, 95% confidence interval 0.47-0.88; P = 0.0061; median 21.0 versus 15.3 months). The most common grade ≥3 treatment-emergent adverse events were neutropenia, leukopenia and anemia. SG demonstrated significant and clinically meaningful improvement in PFS and OS versus chemotherapy, with a manageable safety profile consistent with prior studies. SG represents a promising treatment option for Asian patients with HR+HER2- mBC (ClinicalTrials.gov identifier no. NCT04639986 ).

Pharmacokinetics and pharmacogenomics of ribociclib in black patients with metastatic breast cancer the LEANORA study

Underrepresented populations’ participation in clinical trials remains limited, and the potential impact of genomic variants on drug metabolism remains elusive. This study aimed to assess the pharmacokinetics (PK) and pharmacogenomics (PGx) of ribociclib in self-identified Black women with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2) advanced breast cancer. LEANORA (NCT04657679) was a prospective, observational, multicenter cohort study involving 14 Black women. PK and PGx were evaluated using tandem mass spectrometry and PharmacoScan™ microarray (including CYP3A5*3, *6, and *7). CYP3A5 phenotypes varied among participants: 7 poor metabolizers (PM), 6 intermediate metabolizers (IM), and one normal metabolizer (NM). The area under the curve did not significantly differ between PMs (39,230 h*ng/mL) and IM/NMs (43,546 h*ng/mL; p = 0.38). The incidence of adverse events (AEs) was also similar. We found no association between CYP3A5 genotype and ribociclib exposure. Continued efforts are needed to include diverse populations in clinical trials to ensure equitable treatment outcomes.

The different sequences of CDK4/6 inhibitor and mTOR inhibitor in HR+/HER2-advanced breast cancer: A multicenter real-world study

BackgroundCyclin-dependent kinase 4/6 inhibitor (CDK4/6i) and everolimus (EVE) are effective for patients with hormone receptor–positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (MBC). However, the efficacy of different sequences of CDK4/6i and EVE are largely unknown. The study aimed to explore the efficacy of different sequences in China. Methods146 patients with HR+/HER2- MBC who received both CDK4/6i and EVE in salvage setting were collected. Objective response rate (ORR), clinical benefit rate (CBR), progression-free survival (PFS), and overall survival (OS) were investigated. Results56 patients received CDK4/6i prior to EVE (Group A), 90 patients received CDK4/6i subsequent to EVE (Group B). The median PFS of CDK4/6i and EVE in Group A vs Group B were 8.4m and 2.5m vs 4.6m and 6.1m respectively. The total PFS of first-line and second-line endocrine therapy were not different between Group A and Group B [13.1m vs 17.7m (P = 0.330, HR = 0.738, 95%CI: 0.399–1.365)]. The 5y OS of patients in Group A or Group B were 62.0 % vs 57.4 %, P = 0.569. ConclusionsWe found that no matter CDK4/6i or EVE was used first, the survival were not significantly different between Group A and Group B. Both can be clinical options.

Statin use and risks of breast cancer recurrence and mortality.

Preclinical evidence suggests improved breast cancer survival associated with statin use, but findings from observational studies are conflicting and remain inconclusive. The objective of this study was to assess the association between statin use after cancer diagnosis and cancer outcomes among breast cancer patients. In this retrospective cohort study, 38,858 women aged ≥66 years who were diagnosed with localized and regional stage breast cancer from 2008 through 2017 were identified from the linked Surveillance, Epidemiology, and End Results Medicare database. Statin use was ascertained from Medicare Part D pharmacy claims data. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between post-diagnosis statin use and risks of breast cancer recurrence and breast cancer-specific mortality. Over a median follow-up of 2.9 years for recurrence and 3.7 years for mortality, 1446 women experienced a recurrence, and 2215 died from breast cancer. The mean duration of post-diagnosis statin use was 2.2 years. Statin use post-diagnosis was not associated with recurrence risk (HR, 1.05; 95% CI, 0.91-1.21), but was associated with a reduced risk of cancer-specific mortality (HR, 0.85; 95% CI, 0.75-0.96). The reduction was more pronounced in women with hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer (HR, 0.71; 95% CI, 0.57-0.88). These findings suggest that post-diagnosis statin use is associated with improved cancer-specific survival in women with breast cancer and should be confirmed in randomized trials of statin therapy in breast cancer patients.

Neutrophil-to-lymphocyte ratio at the end of treatment with CDK4/6 inhibitors is an independent prognostic factor for ER-positive HER2-negative advanced breast cancer.

The aim of this study was to elucidate the clinical significance of peripheral blood biomarkers, including absolute lymphocyte count (ALC) and neutrophil-to-lymphocyte ratio (NLR), at the end of treatment (EOT) with CDK4/6 inhibitors abemaciclib and palbociclib in patients with estrogen receptor-positive human epidermal growth factor receptor 2-negative advanced breast cancer. We included 67 patients treated with fulvestrant plus abemaciclib or palbociclib. Overall survival (OS) since the EOT with CDK/4/6 inhibitors was compared in relation to the levels of ALC and NLR. The cut-off values of ALC and NLR were set at 1000/μL and 3, respectively. Patients with a high ALC at EOT showed significantly longer OS than those with a low ALC (p = 0.0358). Moreover, patients with a low NLR at EOT showed significantly longer OS than those with a high NLR at EOT (p = 0.0044). Looking at the changes of ALC and NLR between baseline and the EOT, patients with a high ALC both at baseline and at the EOT showed significantly longer OS than others (p = 0.0201). Similarly, patients with a low NLR both at baseline and at the EOT showed significantly longer OS after EOT than others (p = 0.0136). Multivariable analysis revealed that the NLR at EOT (low vs. high) and changes in NLR (low at baseline to low at EOT vs. others) were significant and independent prognostic factors for OS after EOT (p = 0.0337, p = 0.0039, respectively). NLR at EOT with CDK4/6 inhibitors is a significant and independent prognostic marker for patients with ER-positive HER2-negative advanced breast cancer.

Major considerations on the relationship of triple negative breast cancer with microRNAs and nutrological triggers: a systematic review

Introduction: Triple-negative breast cancer (TNBC) accounts for 15% of all cases. Its incidence is usually higher in young women (under 40 years of age). The classification as triple-negative occurs because, in this case, there are no estrogen, progesterone, and HER2 receptors, which are responsible for controlling tumor growth. Higher levels of physical activity and better diet quality are associated with lower mortality from breast cancer in observational studies. Furthermore, physical activity and optimal nutrition can improve the relative dose intensity of chemotherapy, as they can activate miRNAs that regulate several biological processes. Objective: This was to conduct a systematic review to establish the main considerations of the relationship between triple-negative breast cancer and microRNAs as biomarkers and regulators of gene expression in cancer cells, as well as to show some nutritional triggers of microRNA activation desirable for breast cancer control. Methods: The PRISMA Platform systematic review rules were followed. The search was conducted from April to June 2024 in the Web of Science, Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE and AMSTAR-2 instrument and the risk of bias was analyzed appropriately. According to the Cochrane instrument. Results and Conclusion: 112 articles were found, and 40 were evaluated in full and included in this article, 22 of which were included in the systematic review. Considering the Cochrane tool for risk of bias, the global assessment resulted in 15 studies with a high risk of bias and 25 studies that did not reach GRADE and AMSTAR-2. Most studies showed homogeneity in their results, with X2=81.5%>50%. It was concluded that an increasing number of studies have shown that non-coding RNA (ncRNA), including microRNA (miRNA) and long non-coding RNA (lncRNA), play a significant role in tumorigenesis. Although a diet and exercise intervention did not affect relative dose intensity, the intervention was associated with a higher pCR in patients with hormone receptor-positive/human epidermal growth factor receptor 2-negative and triple-negative breast cancer undergoing neoadjuvant chemotherapy. High expression levels of miR-27a/b, miR-210, and miR-454 were associated with shorter overall survival, whereas high expression levels of miR-454 and miR-374a/b were associated with disease-free survival. The miRNAs associated with triple-negative breast cancer may provide new avenues for early diagnosis and treatment of breast cancer. Furthermore, specific miRNAs may serve as potential prognostic biomarkers in triple-negative breast cancer.

Datopotamab Deruxtecan Versus Chemotherapy in Previously Treated Inoperable/Metastatic Hormone Receptor-Positive Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer: Primary Results From TROPION-Breast01.

The global, phase 3, open-label, randomized TROPION-Breast01 study assessed the trophoblast cell surface antigen 2-directed antibody-drug conjugate datopotamab deruxtecan (Dato-DXd) versus investigator's choice of chemotherapy (ICC) in hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) breast cancer. Adult patients with inoperable/metastatic HR+/HER2‒ breast cancer, who had disease progression on endocrine therapy, for whom endocrine therapy was unsuitable, and had received one to two previous lines of chemotherapy in the inoperable/metastatic setting, were randomly assigned 1:1 to Dato-DXd (6 mg/kg once every 3 weeks) or ICC (eribulin/vinorelbine/capecitabine/gemcitabine). Dual primary end points were progression-free survival (PFS) by blinded independent central review (BICR) and overall survival (OS). Patients were randomly assigned to Dato-DXd (n = 365) or ICC (n = 367). Dato-DXd significantly reduced the risk of progression or death versus ICC (PFS by BICR hazard ratio [HR], 0.63 [95% CI, 0.52 to 0.76]; P < .0001). Consistent PFS benefit was observed across subgroups. Although OS data were not mature, a trend favoring Dato-DXd was observed (HR, 0.84 [95% CI, 0.62 to 1.14]). The rate of grade ≥3 treatment-related adverse events (TRAEs) with Dato-DXd was lower than ICC (20.8% v 44.7%). The most common TRAEs (any grade; grade ≥3) were nausea (51.1%; 1.4%) and stomatitis (50%; 6.4%) with Dato-DXd and neutropenia (grouped term, 42.5%; 30.8%) with ICC. Patients receiving Dato-DXd had statistically significant and clinically meaningful improvement in PFS and a favorable and manageable safety profile, compared with ICC. Results support Dato-DXd as a novel treatment option for patients with inoperable/metastatic HR+/HER2‒ breast cancer who have received one to two previous lines of chemotherapy in this setting.

Cost-effectiveness of early vs delayed use of abemaciclib combination therapy for patients with high-risk hormone receptor-positive/human epidermal growth factor receptor 2-negative early breast cancer.

Abemaciclib was newly approved for hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) high-risk early breast cancer (EBC). Clinical guidelines recommended abemaciclib as the first-line treatment for HR+/ HER2- EBC (early use) or HR+/ HER2- metastatic breast cancer (MBC) (delayed use). To compare the cost-effectiveness of early vs delayed use of abemaciclib for treatment of HR+/HER2- high-risk EBC. Early use was defined as combined abemaciclib and endocrine therapy as first-line therapy for EBC, followed by treatment with fulvestrant for MBC. Delayed use was defined as endocrine therapy for EBC, followed by combined abemaciclib and fulvestrant therapy for MBC. A 5-state model was developed to estimate lifetime costs, life-years (LYs), and quality-adjusted life-years (QALYs) of hypothetical patients with HR+/ HER2- EBC from a third-party US payer's perspective. Key clinical and safety data were derived from the monarchE and MONARCH 2 clinical trials. Costs, utilities, and disutility values of adverse events were obtained from the literature. We calculated the incremental cost-effectiveness ratio (ICER) of early vs delayed abemaciclib use and compared it with a willingness-to-pay (WTP) threshold of $100,000 per LY or QALY. Deterministic and probabilistic sensitivity analyses (PSAs) were performed to test the robustness of the base-case model. Base-case analysis showed early use yielded 21.08 LYs and 17.93 QALYs for $586,213 and delayed use yielded 11.14 LYs and 9.38 QALYs for $157,576. The ICER of early vs delayed use was $43,136/LY and $50,104/QALY, which was cost-effective at the WTP threshold of $100,000. The PSA result indicated that a 94.6% likelihood of early use (vs delayed use) was cost-effective at the WTP threshold of $100,000 per QALY. This study suggests that giving abemaciclib in the early stage rather than waiting until patients develop metastatic disease (current standard of care in MBC) is a cost-effective strategy.

374P Real-world (Rw) outcomes in patients (pts) with hormone receptor-positive and human epidermal growth factor receptor-2 negative (HR+/HER2-) metastatic breast cancer (mBC) treated with chemotherapy (CT) in France and Germany

374P Real-world (Rw) outcomes in patients (pts) with hormone receptor-positive and human epidermal growth factor receptor-2 negative (HR+/HER2-) metastatic breast cancer (mBC) treated with chemotherapy (CT) in France and Germany

Determining Clinicopathologic Factors That Influence Treatment in Advanced Breast Cancer in Argentina After CDK4/6 Inhibitors.

The optimal treatment sequence for hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) after progression on first-line cyclin-dependent kinase 4/6 inhibitor (CDKi) and endocrine therapy is unclear. Clinical and biological factors influencing treatment choices and outcomes in the second-line setting need to be elucidated. This is a retrospective analysis of a real-world cohort including patients with HR+/HER2- ABC who received CDKi and endocrine therapy in the first-line setting and progressed, requiring second-line treatment. Clinical and biological factors were analyzed to evaluate their association with daily treatment decisions and the prognostic role of progression-free survival (PFS) in the second-line setting. Two hundred thirty-five patients were included. Second-line treatments were hormone therapy (HT) based in 60% and chemotherapy based in 40% of patients. The second-line median PFS was 6.6 months, with no difference between treatment types. In multivariable analysis, postmenopausal status, lower Ki-67 expression, and non-de novo stage IV disease were associated with improved second-line (2L) PFS. Menopausal status significantly interacted with treatment type, with reduced PFS in premenopausal patients receiving HT-based treatments (4.7 v 8.7 months, P = .00045). In our study, treatment decisions reflected the current algorithm incorporated in our clinical guidelines, and prior treatment response was the most relevant factor to determine 2L treatment decision. Menopausal status interacted with the subsequent therapy efficacy in this setting. Hence, we consider that menopausal status should be routinely evaluated in the subgroup analysis of clinical trials.

Palbociclib: Randomized Studies and Real-world Evidence as the Basis for Therapeutic Planning in Metastatic Breast Cancer.

Endocrine-based combination therapy with an inhibitor of the cyclin-dependent kinases 4 and 6 (CDK4/6 inhibitors) is currently the first-line therapy of choice for patients with hormone receptor-positive (HR+) and human epidermal growth factor receptor 2-negative (HER2-), locally advanced or metastatic breast cancer (mBC). The efficacy and safety of the treatment with palbociclib, the first CDK4/6 inhibitor approved for this indication, have been confirmed in large randomized controlled clinical trials (RCTs) with strictly defined patient cohorts. Since then, many relevant questions about CDK4/6 inhibition with palbociclib for mBC have been investigated in RCTs and real-world studies. Based on this evidence, palbociclib is widely used in clinical practice since many years because of its efficacy and good tolerability. The aim of this review is to summarize findings from RCTs and RWE considering clinically relevant aspects such as safety, tolerability, quality of life and efficacy with a focus on specific questions and patient characteristics. A critical discussion and review of the overall evidence for endocrine-based therapy with the CDK4/6 inhibitor palbociclib can contribute to support therapy decisions in daily clinical practice.

359P Overall survival of palbociclib (PAL) + endocrine therapy (ET) in Japanese patients with hormone receptor-positive (HR+)/ human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) in the 1st line (1L) or 2nd line (2L) setting: A multicenter observational study

359P Overall survival of palbociclib (PAL) + endocrine therapy (ET) in Japanese patients with hormone receptor-positive (HR+)/ human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) in the 1st line (1L) or 2nd line (2L) setting: A multicenter observational study