Imlunestrant, an oral selective estrogen receptor degrader, as monotherapy and combined with abemaciclib, in recurrent/advanced ER-positive endometrioid endometrial cancer: Results from the phase 1a/1b EMBER study.

OBJECTIVE: Imlunestrant is a next-generation oral selective estrogen receptor degrader designed to deliver continuous estrogen receptor (ER) target inhibition. EMBER is a phase 1a/b trial of imlunestrant, as monotherapy and combined with targeted therapy, in patients with ER+ advanced breast cancer or endometrioid endometrial cancer (EEC). This report focuses on patients with ER+ EEC. METHODS: EMBER used an i3 + 3 dose-escalation design to determine the recommended phase 2 dose (RP2D) followed by dose-expansion cohorts (1:1 randomization): imlunestrant monotherapy and imlunestrant plus abemaciclib (150 mg twice daily). Eligible patients had measurable disease and progression or recurrence after platinum-containing chemotherapy. Prior fulvestrant or aromatase inhibitor was not allowed. Secondary endpoints included safety, pharmacokinetics and antitumor activity. RESULTS: In total, 72 patients with a median of 2 prior anticancer therapies were treated. Among the 39 patients who received imlunestrant (400 mg [RP2D], n = 33; 800 mg, n = 6), the most common treatment-emergent adverse events (TEAEs) were grade 1-2 nausea (35.9 %), diarrhea (25.6 %), urinary tract infection (25.6 %), and abdominal pain (20.5 %). Overall response rate (ORR) was 10.3 %, clinical benefit rate (CBR) was 33.3 %, and median progression-free survival (mPFS) was 3.8 months (95 % CI, 1.8-6.7). Among the 33 patients who received imlunestrant (400 mg [RP2D], n = 29; 800 mg, n = 4) plus abemaciclib, the most common TEAEs were diarrhea (87.9 %), nausea (66.7 %), fatigue (48.5 %), and anemia (45.5 %). ORR was 18.2 %, CBR was 42.4 %, and mPFS was 6.8 months (95 % CI, 2.1-12). CONCLUSION: Imlunestrant, as monotherapy and combined with abemaciclib, has a manageable safety profile with preliminary evidence of antitumor activity in patients with ER+ EEC.

The DEBBRAH trial: Trastuzumab deruxtecan in HER2-positive and HER2-low breast cancer patients with leptomeningeal carcinomatosis.

BACKGROUND: Leptomeningeal disease (LMD) is associated with poor survival and diminished quality of life. Trastuzumab deruxtecan (T-DXd) has shown remarkable intracranial and extracranial activity in human epidermal growth factor receptor 2 (HER2)-positive and HER2-low advanced breast cancer (ABC). The DEBBRAH trial was designed to evaluate its efficacy and safety in patients with HER2-positive and HER2-low ABC with a history of brain metastases (BMs) and/or LMD. Here, we report results from cohort 5, which specifically included patients with pathologically confirmed LMD. METHODS: This single-arm, open-label, five-cohort, phase 2 trial enrolled seven patients in cohort 5 who received 5.4 mg/kg T-DXd intravenously every 21 days until disease progression or unacceptable toxicity. The primary endpoint was overall survival (OS). Key secondary endpoints included progression-free survival (PFS) and safety profile. FINDINGS: At data cutoff (April 4, 2023), the median duration of follow-up was 12.0 months (range, 2.5-18.6). The median OS was 13.3 months (95% confidence interval [CI], 5.7-NA, p < 0.001), meeting the primary endpoint. The median PFS was 8.9 months (95% CI, 2.1-NA). Two (28.6%) of seven patients remained on treatment after 18.6 and 11.9 months, respectively. Of the five patients who progressed and died, none had intracranial progression or clinical worsening of leptomeningeal symptoms. Notably, 71.4% (95% CI, 29.0-96.3) achieved prolonged stabilization (≥24 weeks) by response evaluation criteria in solid tumors (RECIST) v.1.1. No unexpected safety signals and no treatment-related deaths were observed. CONCLUSIONS: T-DXd showed promising antitumor activity in patients with HER2-positive and HER2-low ABC with previously untreated, pathologically confirmed LMD. These encouraging data warrant further investigation to address the unmet need in this difficult-to-treat condition. FUNDING: This work was funded by Daiichi Sankyo/AstraZeneca. This trial is registered with ClinicalTrials.gov: NCT04420598.

High mechanical conditioning by tumor extracellular matrix stiffness is a predictive biomarker for anti-fibrotic therapy in HER2-negative breast cancer.

BACKGROUND: Tumor progression has been linked to stiffening of the extracellular matrix (ECM) caused by fibrosis. Cancer cells can be mechanically conditioned by stiff ECM, exhibiting a 1004-gene signature (MeCo score). Nintedanib has demonstrated anti-fibrotic activity in idiopathic pulmonary fibrosis. This study explores nintedanib's anti-fibrotic effect on breast cancer outcomes. METHODS: We present long-term follow-up and analysis of a neoadjuvant randomized Phase 2 trial in early HER2-negative breast cancer. Patients (N = 130) underwent a baseline biopsy and received 12 paclitaxel courses alone (control arm) or in combination with nintedanib (experimental arm). Tumor MeCo score was determined by RNAseq. The primary aim was to assess nintedanib's impact on event-free survival (EFS) based on MeCo scores. RESULTS: Follow-up data were retrieved from 111 patients; 75 baseline and 24 post-run-in phase samples were sequenced. After median follow-up of 9.67 years, median EFS was not statistically different between arms (P = 0.37). However, in the control arm, High versus Low MeCo patients had a statistically higher relapse risk: hazard ratio (HR) = 0.21; P = 0.0075. This risk was corrected by nintedanib in the experimental arm: HR = 0.37; P = 0.16. Nintedanib demonstrated pharmacodynamic engagement, reducing the MeCo score by 25% during the run-in phase (P<0.01). Patients with Low MeCo after run-in had the best long-term prognosis (HR = 0.087; P = 0.03). CONCLUSIONS: High MeCo is predictive of poor outcomes in HER2-negative early breast cancer, although this risk can be mitigated by nintedanib, which is able to specifically reduce mechanical conditioning.

Olaparib plus trastuzumab in HER2-positive advanced breast cancer patients with germline BRCA1/2 mutations: The OPHELIA phase 2 study.

PURPOSE: To evaluate the efficacy and safety of the combination of olaparib plus trastuzumab in patients with HER2-positive advanced breast cancer (ABC) and germinal BRCA mutations (gBRCAm). METHODS: OPHELIA (NCT03931551) was a single-arm, open-label, phase 2 clinical trial. Patients aged ≥18 years diagnosed with HER2-positive ABC with germinal deleterious mutations in BRCA1 or BRCA2 who had received at least one prior systemic regimen for advanced disease were enrolled. Patients received olaparib plus trastuzumab until disease progression, unacceptable toxicity, or consent withdrawal. The primary endpoint was investigator-assessed clinical benefit rate for at least 24 weeks as per RECIST v.1.1. Key secondary endpoints included overall response rate (ORR) and safety profile. RESULTS: A total of 68 pre-treated HER2-positive ABC patients were screened. Due to slow accrual the trial was stopped after enrolling 5 patients instead of the planned sample size of 20. Four patients achieved clinical benefit (80.0 %, 95 % CI; 28.4-99.5, p < 0.001) and the primary endpoint was met. The ORR was 60.0 % (95 % CI; 14.7-94.7), including one complete response. Four (80.0 %) patients experienced at least one treatment-related treatment-emergent adverse event (TEAE). Most TEAEs were grade 1 or 2. There were no treatment-related deaths and no new safety signals were identified. CONCLUSIONS: This study suggests that the combination of olaparib plus trastuzumab may be effective and safe in pre-treated patients with HER2-positive gBRCAm ABC. This ABC patient population should be further studied and not be pre-emptively excluded from clinical trials of targeted therapy for BRCA1/2-driven cancers.

Cross-sectional and longitudinal associations of adherence to WCRF/AICR cancer prevention recommendations with health-related quality of life in breast cancer survivors. Health-EpiGEICAM study.

OBJECTIVES: Adherence to healthy lifestyle recommendations has been reported to improve health-related quality of life (HRQL) in breast cancer (BC) patients, but the influence of long-term behavioral changes remains unknown. We evaluated the association between adherence to the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations and HRQL both, at BC diagnosis and the change 7-12 years later. DESIGN: Prospective cohort study. SETTINGS AND PARTICIPANTS: A total of 406 breast cancer survivors, from the EpiGEICAM study, were recruited in 16 Spanish hospitals. MEASUREMENTS: Epidemiological, clinical, dietary, physical activity and HRQL information was collected both at recruitment and 7-12 years later. A 7-item score to measure compliance with recommendations was assessed according to the 2018 WCRF/AICR scoring criteria. HRQL was evaluated using SF-36 questionnaire. Linear mixed models for longitudinal data were used to assess the cross-sectional and longitudinal association between adherence score and the physical and mental component summary scores. RESULTS: At diagnosis, for each unit increase in WCRF/AICR score adherence, the HRQL physical domain increased 0.78 points (95%CI: -0.04 to 1.60; P trend:0.06). The mean change in physical HRQL from diagnosis to follow-up per unit increase in within-subject adherence score was 0.73 points (95%CI: -0.18 to 1.65; P trend: 0.12). For the mental domain, no association was observed with compliance with the recommendations at diagnosis, nor with changes in adherence over time. CONCLUSIONS: Our results suggest that Increased adherence to WCRF/AICR cancer prevention recommendations over time could contribute to slightly improved long-term physical HRQoL in BC survivors.

Study design for DESTINY-Breast Respond HER2-low Europe: T-DXd in patients with HER2-low advanced breast cancer.

Trastuzumab deruxtecan (T-DXd) is approved for the treatment of human epidermal growth factor receptor 2 (HER2)-low metastatic breast cancer (mBC). Results on T-DXd treatment in HER2-low mBC have so far been limited to clinical trials. DESTINY-Breast Respond HER2-low Europe (NCT05945732) is a multi-center, multi-country, observational, prospective, non-interventional study planning to enroll 1350 patients from 216 sites receiving T-DXd or conventional chemotherapy as their routine clinical care for advanced stage breast cancer in 12 European countries. This non-interventional study will provide real-world insight into T-DXd treatment for HER2-low mBC with data on effectiveness, safety and tolerability, patient-reported outcomes, treatment patterns, geriatric health status and HER2 testing. This will be beneficial for improving guidance to maximize patient treatment benefit.

Trastuzumab deruxtecan (T-DXd; Enhertu^®) is a medicine approved to treat cancers that produce a protein called HER2 on the surface of cancer cells. T-DXd works by targeting the HER2 protein to deliver chemotherapy directly to cancer cells. Until recently, breast cancers were classified as HER2-positive (high level of HER2 protein on cancer cells) or HER2-negative (very low level/no HER2 protein on cancer cells). T-DXd was approved for treating patients with HER2-positive advanced breast cancer in Europe in 2022. In 2023 the DESTINY-Breast04 clinical trial showed that T-DXd was more effective than current standard chemotherapies, when treating advanced breast cancer patients with low levels of the HER2 protein (historically classified as HER2-negative cancer). This trial led to the approval of T-DXd for treating advanced HER2-low breast cancer, providing a new treatment option for 50­60% of breast cancer patients. More information is needed about T-DXd treatment in the real world (for patients treated in the hospital, rather than in a clinical trial). This article describes the purpose and design of the DESTINY-Breast Respond HER2-low Europe study, which will collect and report more information about how effective T-DXd treatment is in the real world. This is a large study aiming to include 1350 eligible patients from 12 countries across Europe. Patients will report their experience of side effects (such as nausea and vomiting) to improve management of T-DXd treatment and maximize patient benefit. The study will also examine how elderly patients respond to T-DXd treatment, and how HER2 levels are being tested.Clinical Trial Registration: ICH CGP: NCT05945732, registered on 6 July 2023 (ClinicalTrials.gov).

Tumor-Infiltrating Lymphocytes Refine Outcomes in Triple-Negative Breast Cancer Treated with Anthracycline-Free Neoadjuvant Chemotherapy.

PURPOSE: Stromal tumor-infiltrating lymphocytes (sTIL) are associated with pathologic complete response (pCR) and long-term outcomes for triple-negative breast cancer (TNBC) in the setting of anthracycline-based chemotherapy. The impact of sTILs on refining outcomes beyond prognostic information provided by pCR in anthracycline-free neoadjuvant chemotherapy (NAC) is not known. EXPERIMENTAL DESIGN: This is a pooled analysis of two studies where patients with stage I (T>1 cm)-III TNBC received carboplatin (AUC 6) plus docetaxel (75 mg/m2; CbD) NAC. sTILs were evaluated centrally on pre-treatment hematoxylin and eosin slides using standard criteria. Cox regression analysis was used to examine the effect of variables on event-free survival (EFS) and overall survival (OS). RESULTS: Among 474 patients, 44% had node-positive disease. Median sTILs were 5% (range, 1%-95%), and 32% of patients had ≥30% sTILs. pCR rate was 51%. On multivariable analysis, T stage (OR, 2.08; P = 0.007), nodal status (OR, 1.64; P = 0.035), and sTILs (OR, 1.10; P = 0.011) were associated with pCR. On multivariate analysis, nodal status (HR, 0.46; P = 0.008), pCR (HR, 0.20; P < 0.001), and sTILs (HR, 0.95; P = 0.049) were associated with OS. At 30% cut-point, sTILs stratified outcomes in stage III disease, with 5-year OS 86% versus 57% in ≥30% versus <30% sTILs (HR, 0.29; P = 0.014), and numeric trend in stage II, with 5-year OS 93% versus 89% in ≥30% versus <30% sTILs (HR, 0.55; P = 0.179). Among stage II-III patients with pCR, EFS was better in those with ≥30% sTILs (HR, 0.16; P, 0.047). CONCLUSIONS: sTILs density was an independent predictor of OS beyond clinicopathologic features and pathologic response in patients with TNBC treated with anthracycline-free CbD chemotherapy. Notably, sTILs density stratified outcomes beyond tumor-node-metastasis (TNM) stage and pathologic response. These findings highlight the role of sTILs in patient selection and stratification for neo/adjuvant escalation and de-escalation strategies.

Safety profile of trastuzumab deruxtecan in advanced breast cancer: Expert opinion on adverse event management.

Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate that targets human epidermal growth factor receptor 2 (HER2) and has shown promising results in the treatment of advanced/metastatic breast cancer. The objective of this report is to provide guidance on the prophylaxis, monitoring, and management of adverse events (AEs) in patients with breast cancer treated with T-DXd, and to emphasize that proper management of AEs is needed to optimize the effectiveness of T-DXd treatment and reduce the number of discontinuations. The article covers various aspects of T-DXd treatment, including its clinical efficacy, safety profile, and dosing considerations, and provides practical recommendations for managing AEs, such as nausea/vomiting, interstitial lung disease, and hematologic toxicity. Although there are still many knowledge gaps about the cause and incidence of AEs in real-world patients, this document may serve as a valuable resource for clinicians who are involved in the care of breast cancer patients receiving T-DXd treatment.

Correlation between breast cancer subtypes determined by immunohistochemistry and n-COUNTER PAM50 assay: a real-world study.

PURPOSE: Molecular subtyping based on gene expression profiling (i.e., PAM50 assay) aids in determining the prognosis and treatment of breast cancer (BC), particularly in hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors, where luminal A and B subtypes have different prognoses and treatments. Several surrogate classifications have been proposed for distinguishing between the luminal A and B subtypes. This study determines the accuracy of local immunohistochemistry (IHC) techniques for classifying HR-positive/HER2-negative (HR+/HER2-) tumors according to intrinsic subtypes using the nCOUNTER PAM50 assay as reference and the HR status definition according the ASCO/CAP recommendations. METHODS: Molecular subtypes resulting from nCOUNTER PAM50 performed in our laboratory between 2014 and 2020 were correlated with three different proxy surrogates proposed in the literature based on ER, PR, HER2, and Ki67 expression with different cut-off values. Concordance was measured using the level of agreement and kappa statistics. RESULTS: From 1049 samples with the nCOUNTER test, 679 and 350 were luminal A and B subtypes, respectively. Only a poor-to-fair correlation was observed between the three proxy surrogates and real genomic subtypes as determined by nCOUNTER PAM50. Moreover, 5-11% and 18-36% of the nCOUNTER PAM50 luminal B and A tumors were classified as luminal A and B, respectively, by these surrogates. CONCLUSION: The concordance between luminal subtypes determined by three different IHC-based classifiers and the nCOUNTER PAM50 assay was suboptimal. Thus, a significant proportion of luminal A and B tumors as determined by the surrogate classifiers could be undertreated or over-treated.

Patient-reported outcomes in high-risk HR+ /HER2- early breast cancer patients treated with endocrine therapy with or without palbociclib within the randomized PENELOPEB study.

BACKGROUND: The PENELOPEB trial investigating efficacy and safety of additional 1-year post-neoadjuvant palbociclib to standard endocrine therapy (ET) high-risk hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) early breast cancer patients failed to improve invasive disease-free survival (iDFS). This analysis compared patient-reported outcomes (PROs) between treatment groups. PATIENTS AND METHODS: Patients received 13 cycles of palbociclib 125 mg/day (n = 631) or placebo (n = 619) orally for 3 out of 4 weeks + ET. European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire (EORTC QLQ-C30), its breast cancer (BR23) and fatigue (FA13) modules, mood questionnaire GAD7 and European Quality of Life 5 Dimensions (EQ-5D) instruments were used for the assessment of quality of life (QoL). Repeated-measures mixed-effects models were used to evaluate differences in PRO, changes of PRO over time, and treatment-by-time interactions. RESULTS: 924 of 1250 patients (73.9%) completed baseline and at least one post-baseline questionnaire of all PRO instruments. General health status (GHS)/QoL based on EORTC QLQ-C30 was high in both arms (mean [SD]: palbociclib 70.1 [19.3], placebo 71.4 [18.8]) and was slightly higher in the placebo arm (LeastSquare mean difference: 0.82, p < 0.001). Higher fatigue was reported in the palbociclib arm (mean [SD]: 30.3 [23.8] vs. placebo 28.3 [22.7]; p < 0.001). No statistically significant differences were observed among FA13 physical, cognitive, and emotional fatigue subscales. CONCLUSION: Patient-reported global QoL and fatigue did not substantially change in both treatment arms. Slight differences in GHS, physical functioning, and fatigue favored the placebo arm statistically without achieving clinically meaningful thresholds.

Clinical Experience with Abemaciclib in Patients Previously Treated with Another CDK 4/6 Inhibitor in a Tertiary Hospital: A Case Series Study.

The three approved cyclin-dependent kinase 4/6 (CDK4/6) inhibitors, including abemaciclib, have shown differences in their preclinical, pharmacological, and clinical data. Abemaciclib stands out for its broader target range and more rapid and intense activity. It has demonstrated efficacy as a monotherapy or in combination with tamoxifen in endocrine-refractory metastatic breast cancer (MBC) patients with prior chemotherapy. However, the clinical data on abemaciclib after exposure to previous CDK4/6 inhibitors are limited. In this single-center retrospective case series, we identified all patients who received abemaciclib until February 2022 after experiencing documented progression on palbociclib or ribociclib. The safety profile and clinical outcomes of abemaciclib treatment in this specific patient cohort were evaluated. Eleven patients were included in this retrospective case series, nine receiving abemaciclib with tamoxifen. Eight patients had visceral involvement, and the median age was 69 (ranging from 42 to 84). The median time from the end of prior CDK4/6 inhibitor treatment to abemaciclib initiation was 17.5 months (ranging from 3 to 41 months). Patients had undergone a median of three prior therapies (ranging from 1 to 7), including chemotherapy in 54.5% of cases. The median follow-up time was six months (ranging from 1 to 22 months). The median progression-free survival (PFS) was 8 months (95% CI 3.9-12). Five patients continued abemaciclib treatment, and one patient with liver metastases achieved a complete hepatic response. The most common adverse events were diarrhea (72.7%, no grade ≥ 3) and asthenia (27.3%, no grade ≥ 3). Our preliminary findings suggest that abemaciclib could be an effective and safe treatment option for MBC patients who have previously received palbociclib or ribociclib.

Intermediate Molecular Phenotypes to Identify Genetic Markers of Anthracycline-Induced Cardiotoxicity Risk.

Cardiotoxicity due to anthracyclines (CDA) affects cancer patients, but we cannot predict who may suffer from this complication. CDA is a complex trait with a polygenic component that is mainly unidentified. We propose that levels of intermediate molecular phenotypes (IMPs) in the myocardium associated with histopathological damage could explain CDA susceptibility, so variants of genes encoding these IMPs could identify patients susceptible to this complication. Thus, a genetically heterogeneous cohort of mice (n = 165) generated by backcrossing were treated with doxorubicin and docetaxel. We quantified heart fibrosis using an Ariol slide scanner and intramyocardial levels of IMPs using multiplex bead arrays and QPCR. We identified quantitative trait loci linked to IMPs (ipQTLs) and cdaQTLs via linkage analysis. In three cancer patient cohorts, CDA was quantified using echocardiography or Cardiac Magnetic Resonance. CDA behaves as a complex trait in the mouse cohort. IMP levels in the myocardium were associated with CDA. ipQTLs integrated into genetic models with cdaQTLs account for more CDA phenotypic variation than that explained by cda-QTLs alone. Allelic forms of genes encoding IMPs associated with CDA in mice, including AKT1, MAPK14, MAPK8, STAT3, CAS3, and TP53, are genetic determinants of CDA in patients. Two genetic risk scores for pediatric patients (n = 71) and women with breast cancer (n = 420) were generated using machine-learning Least Absolute Shrinkage and Selection Operator (LASSO) regression. Thus, IMPs associated with heart damage identify genetic markers of CDA risk, thereby allowing more personalized patient management.

Real-World Use of Highly Sensitive Liquid Biopsy Monitoring in Metastatic Breast Cancer Patients Treated with Endocrine Agents after Exposure to Aromatase Inhibitors.

Endocrine-resistant, hormone receptor-positive, and HER2-negative (HR+/HER2-) metastatic breast cancer (mBC) is largely governed by acquired mutations in the estrogen receptor, which promote ligand-independent activation, and by truncal alterations in the PI3K signaling pathway, with a broader range of gene alterations occurring with less prevalence. Circulating tumor DNA (ctDNA)-based technologies are progressively permeating the clinical setting. However, their utility for serial monitoring has been hindered by their significant costs, inter-technique variability, and real-world patient heterogeneity. We interrogated a longitudinal collection of 180 plasma samples from 75 HR+/HER2- mBC patients who progressed or relapsed after exposure to aromatase inhibitors and were subsequently treated with endocrine therapy (ET) by means of highly sensitive and affordable digital PCR and SafeSEQ sequencing. Baseline PIK3CA and TP53 mutations were prognostic of a shorter progression-free survival in our population. Mutant PIK3CA was prognostic in the subset of patients receiving fulvestrant monotherapy after progression to a CDK4/6 inhibitor (CDK4/6i)-containing regimen, and its suppression was predictive in a case of long-term benefit with alpelisib. Mutant ESR1 was prognostic in patients who did not receive concurrent CDK4/6i, an impact influenced by the variant allele frequency, and its early suppression was strongly predictive of efficacy and associated with long-term benefit in the whole cohort. Mutations in ESR1, TP53, and KRAS emerged as putative drivers of acquired resistance. These findings collectively contribute to the characterization of longitudinal ctDNA in real-world cases of HR+/HER2- mBC previously exposed to aromatase inhibitors and support ongoing studies either targeting actionable alterations or leveraging the ultra-sensitive tracking of ctDNA.

XENERA-1: a randomised double-blind Phase II trial of xentuzumab in combination with everolimus and exemestane versus everolimus and exemestane in patients with hormone receptor-positive/HER2-negative metastatic breast cancer and non-visceral disease.

BACKGROUND: Xentuzumab is a humanised monoclonal antibody that binds to IGF-1 and IGF-2, neutralising their proliferative activity and restoring inhibition of AKT by everolimus. This study evaluated the addition of xentuzumab to everolimus and exemestane in patients with advanced breast cancer with non-visceral disease. METHODS: This double-blind, randomised, Phase II study was undertaken in female patients with hormone-receptor (HR)-positive/human epidermal growth factor 2 (HER2)-negative advanced breast cancer with non-visceral disease who had received prior endocrine therapy with or without CDK4/6 inhibitors. Patients received a weekly intravenous infusion of xentuzumab (1000 mg) or placebo in combination with everolimus (10 mg/day orally) and exemestane (25 mg/day orally). The primary endpoint was progression-free survival (PFS) per independent review. RESULTS: A total of 103 patients were randomised and 101 were treated (n = 50 in the xentuzumab arm and n = 51 in the placebo arm). The trial was unblinded early due to high rates of discordance between independent and investigator assessment of PFS. Per independent assessment, median PFS was 12.7 (95% CI 6.8-29.3) months with xentuzumab and 11.0 (7.7-19.5) months with placebo (hazard ratio 1.19; 95% CI 0.55-2.59; p = 0.6534). Per investigator assessment, median PFS was 7.4 (6.8-9.7) months with xentuzumab and 9.2 (5.6-14.4) months with placebo (hazard ratio 1.23; 95% CI 0.69-2.20; p = 0.4800). Tolerability was similar between the arms, with diarrhoea (33.3-56.0%), fatigue (33.3-44.0%) and headache (21.6-40.0%) being the most common treatment-emergent adverse events. The incidence of grade ≥ 3 hyperglycaemia was similar between the xentuzumab (2.0%) and placebo (5.9%) arms. CONCLUSIONS: While this study demonstrated that xentuzumab could be safely combined with everolimus and exemestane in patients with HR-positive/HER2-negative advanced breast cancer with non-visceral disease, there was no PFS benefit with the addition of xentuzumab. Trial registration ClinicalTrials.gov, NCT03659136. Prospectively registered, September 6, 2018.

SEOM-GEICAM-SOLTI clinical guidelines in advanced breast cancer (2022).

Advanced breast cancer represents a challenge for patients and for physicians due its dynamic genomic changes yielding to a resistance to treatments. The main goal is to improve quality of live and survival of the patients through the most appropriate subsequent therapies based on the knowledge of the natural history of the disease. In these guidelines, we summarize current evidence and available therapies for the medical management of advanced breast cancer.

Assessment of a Genomic Assay in Patients With ERBB2-Positive Breast Cancer Following Neoadjuvant Trastuzumab-Based Chemotherapy With or Without Pertuzumab.

Importance: Biomarkers to guide the use of pertuzumab in the treatment of early-stage ERBB2 (formerly HER2)-positive breast cancer beyond simple ERBB2 status are needed. Objective: To determine if use of the HER2DX genomic assay (Reveal Genomics) in pretreatment baseline tissue samples of patients with ERBB2-positive breast cancer is associated with response to neoadjuvant trastuzumab-based chemotherapy with or without pertuzumab. Design, Setting, and Participants: This is a retrospective diagnostic/prognostic analysis of a multicenter academic observational study in Spain performed during 2018 to 2022 (GOM-HGUGM-2018-05). In addition, a combined analysis with 2 previously reported trials of neoadjuvant cohorts with results from the assay (DAPHNe and I-SPY2) was performed. All patients had stage I to III ERBB2-positive breast cancer, signed informed consent, and had available formalin-fixed paraffin-embedded tumor specimens obtained prior to starting therapy. Exposures: Patients received intravenous trastuzumab, 8 mg/kg, loading dose, followed by 6 mg/kg every 3 weeks in combination with intravenous docetaxel, 75 mg/m2, every 3 weeks and intravenous carboplatin area under the curve of 6 every 3 weeks for 6 cycles, or this regimen plus intravenous pertuzumab, 840 mg, loading dose, followed by an intravenous 420-mg dose every 3 weeks for 6 cycles. Main Outcome and Measures: Association of baseline assay-reported pathologic complete response (pCR) score with pCR in the breast and axilla, as well as association of baseline assay-reported pCR score with response to pertuzumab. Results: The assay was evaluated in 155 patients with ERBB2-positive breast cancer (mean [range] age, 50.3 [26-78] years). Clinical T1 to T2 and node-positive disease was present in 113 (72.9%) and 99 (63.9%) patients, respectively, and 105 (67.7%) tumors were hormone receptor positive. The overall pCR rate was 57.4% (95% CI, 49.2%-65.2%). The proportion of patients in the assay-reported pCR-low, pCR-medium, and pCR-high groups was 53 (34.2%), 54 (34.8%), and 48 (31.0%), respectively. In the multivariable analysis, the assay-reported pCR score (as a continuous variable from 0-100) showed a statistically significant association with pCR (odds ratio [OR] per 10-unit increase, 1.43; 95% CI, 1.22-1.70; P < .001). The pCR rates in the assay-reported pCR-high and pCR-low groups were 75.0% and 28.3%, respectively (OR, 7.85; 95% CI, 2.67-24.91; P < .001). In the combined analysis (n = 282), an increase in pCR rate due to pertuzumab was found in the assay-reported pCR-high tumors (OR, 5.36; 95% CI, 1.89-15.20; P < .001) but not in the assay-reported pCR-low tumors (OR, 0.86; 95% CI, 0.30-2.46; P = .77). A statistically significant interaction between the assay-reported pCR score and the effect of pertuzumab in pCR was observed. Conclusions and Relevance: This diagnostic/prognostic study demonstrated that the genomic assay predicted pCR following neoadjuvant trastuzumab-based chemotherapy with or without pertuzumab. This assay could guide therapeutic decisions regarding the use of neoadjuvant pertuzumab.

Intermediate molecular phenotypes to identify genetic markers of anthracycline-induced cardiotoxicity risk.

Cardiotoxicity due to anthracyclines (CDA) affects cancer patients, but we cannot predict who may suffer from this complication. CDA is a complex disease whose polygenic component is mainly unidentified. We propose that levels of intermediate molecular phenotypes in the myocardium associated with histopathological damage could explain CDA susceptibility; so that variants of genes encoding these intermediate molecular phenotypes could identify patients susceptible to this complication. A genetically heterogeneous cohort of mice generated by backcrossing (N = 165) was treated with doxorubicin and docetaxel. Cardiac histopathological damage was measured by fibrosis and cardiomyocyte size by an Ariol slide scanner. We determine intramyocardial levels of intermediate molecular phenotypes of CDA associated with histopathological damage and quantitative trait loci (ipQTLs) linked to them. These ipQTLs seem to contribute to the missing heritability of CDA because they improve the heritability explained by QTL directly linked to CDA (cda-QTLs) through genetic models. Genes encoding these molecular subphenotypes were evaluated as genetic markers of CDA in three cancer patient cohorts (N = 517) whose cardiac damage was quantified by echocardiography or Cardiac Magnetic Resonance. Many SNPs associated with CDA were found using genetic models. LASSO multivariate regression identified two risk score models, one for pediatric cancer patients and the other for women with breast cancer. Molecular intermediate phenotypes associated with heart damage can identify genetic markers of CDA risk, thereby allowing a more personalized patient management. A similar strategy could be applied to identify genetic markers of other complex trait diseases.

Triple-Negative PAM50 Non-Basal Breast Cancer Subtype Predicts Benefit from Extended Adjuvant Capecitabine.

PURPOSE: Predictive biomarkers for capecitabine benefit in triple-negative breast cancer (TNBC) have been recently proposed using samples from phase III clinical trials, including non-basal phenotype and biomarkers related to angiogenesis, stroma, and capecitabine activation genes. We aimed to validate these findings on the larger phase III GEICAM/CIBOMA clinical trial. EXPERIMENTAL DESIGN: Tumor tissues from patients with TNBC randomized to standard (neo)adjuvant chemotherapy followed by capecitabine versus observation were analyzed using a 164-gene NanoString custom nCounter codeset measuring mRNA expression. A prespecified statistical plan sought to verify the predictive capacity of PAM50 non-basal molecular subtype and tested the hypotheses that breast tumors with increased expression of (meta)genes for cytotoxic cells, mast cells, endothelial cells, PDL2, and 38 individual genes benefit from adjuvant capecitabine for distant recurrence-free survival (DRFS; primary endpoint) and overall survival. RESULTS: Of the 876 women enrolled in the GEICAM/CIBOMA trial, 658 (75%) were evaluable for analysis (337 with capecitabine and 321 without). Of these cases, 553 (84%) were profiled as PAM50 basal-like whereas 105 (16%) were PAM50 non-basal. Non-basal subtype was the most significant predictor for capecitabine benefit [HRcapecitabine, 0.19; 95% confidence interval (CI), 0.07-0.54; P < 0.001] when compared with PAM50 basal-like (HRcapecitabine, 0.9; 95% CI, 0.63-1.28; P = 0.55; Pinteraction<0.001, adjusted P value = 0.01). Analysis of biological processes related to PAM50 non-basal subtype revealed its enrichment for mast cells, extracellular matrix, angiogenesis, and features of mesenchymal stem-like TNBC subtype. CONCLUSIONS: In this prespecified correlative analysis of the GEICAM/CIBOMA trial, PAM50 non-basal status identified patients with early-stage TNBC most likely to benefit from capecitabine.