Adjuvant endocrine therapy with cyclin-dependent kinase 4/6 inhibitor, ribociclib, for localized hormone receptor-positive/HER2- breast cancer (LEADER).

Optimal timing and dosing of adjuvant cyclin-dependent kinase (CDK) 4/6 inhibitor in early breast cancer is controversial. This prospective phase II clinical trial investigated tolerability and safety of two ribociclib dosing schedules. Patients with stage I-III hormone receptor-positive (HR+)/HER2- breast cancer on adjuvant endocrine therapy (ET) were randomized to two ribociclib dosing schedules: 400 mg continuous vs 600 mg intermittent, with initiation in early (prior ET < 2 years) vs delayed (prior ET ≥ 2 years) setting.

TOP1 Mutations and Cross-Resistance to Antibody-Drug Conjugates in Patients with Metastatic Breast Cancer.

Purpose: Antibody-drug conjugates (ADCs) harboring topoisomerase I (TOP1) inhibitor payloads have improved survival for patients with metastatic breast cancer (MBC). However, knowledge of ADC resistance mechanisms and potential impact on sequential use of ADCs is limited. Here, we report the incidence and characterization of TOP1 mutations arising in the setting of ADC resistance in MBC.

A TROP2/Claudin Program Mediates Immune Exclusion to Impede Checkpoint Blockade in Breast Cancer.

Immune exclusion inhibits anti-tumor immunity and response to immunotherapy, but its mechanisms remain poorly defined. Here, we demonstrate that Trophoblast Cell-Surface Antigen 2 (TROP2), a key target of emerging anti-cancer Antibody Drug Conjugates (ADCs), controls barrier-mediated immune exclusion in Triple-Negative Breast Cancer (TNBC) through Claudin 7 association and tight junction regulation. TROP2 expression is inversely correlated with T cell infiltration and strongly associated with outcomes in TNBC.

Ipatasertib plus Paclitaxel for Patients with PIK3CA/AKT1/PTEN-Altered Locally Advanced Unresectable or Metastatic Triple-Negative Breast Cancer in the IPATunity130 Phase III Trial.

Purpose: In the randomized phase II LOTUS trial, combining ipatasertib with first-line paclitaxel for triple-negative breast cancer (TNBC) improved progression-free survival (PFS), particularly in patients with PIK3CA/AKT1/PTEN-altered tumors. We aimed to validate these findings in a biomarker-selected TNBC population.

Patients And Methods: In Cohort A of the randomized double-blind placebo-controlled phase III IPATunity130 trial, taxane-eligible patients with PIK3CA/AKT1/PTEN-altered measurable advanced TNBC and no prior chemotherapy for advanced disease were randomized 2:1 to ipatasertib (400 mg, days 1-21) or placebo, both plus paclitaxel (80 mg/m2, days 1, 8, and 15), every 28 days until disease progression or unacceptable toxicity.

A prospective study of HER3 expression pre and post neoadjuvant therapy of different breast cancer subtypes: implications for HER3 imaging therapy guidance.

Purpose: HER3, a member of the EGFR receptor family, plays a central role in driving oncogenic cell proliferation in breast cancer. Novel HER3 therapeutics are showing promising results while recently developed HER3 PET imaging modalities aid in predicting and assessing early treatment response. However, baseline HER3 expression, as well as changes in expression while on neoadjuvant therapy, have not been well-characterized.

Adjuvant Trastuzumab Emtansine Versus Paclitaxel Plus Trastuzumab for Stage I Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer: 5-Year Results and Correlative Analyses From ATEMPT.

Purpose: Long-term outcomes of patients with stage I human epidermal growth factor receptor 2 (HER2)-positive breast cancer receiving adjuvant trastuzumab emtansine (T-DM1) remain undefined, and prognostic predictors represent an unmet need.

Methods: In the ATEMPT phase II trial, patients with stage I centrally confirmed HER2-positive breast cancer were randomly assigned 3:1 to adjuvant T-DM1 for 1 year or paclitaxel plus trastuzumab (TH). Coprimary objectives were to compare the incidence of clinically relevant toxicities between arms and to evaluate invasive disease-free survival (iDFS) with T-DM1.

Functional hemodynamic imaging markers for the prediction of pathological outcomes in breast cancer patients treated with neoadjuvant chemotherapy.

Significance: Achieving pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) is a significant predictor of increased likelihood of survival in breast cancer patients. Early prediction of pCR is of high clinical value as it could allow personalized adjustment of treatment regimens in non-responding patients for improved outcomes.

Aim: We aim to assess the association between hemoglobin-based functional imaging biomarkers derived from diffuse optical tomography (DOT) and the pathological outcome represented by pCR at different timepoints along the course of NACT.

Antibody-Drug Conjugate Sacituzumab Govitecan Enables a Sequential TOP1/PARP Inhibitor Therapy Strategy in Patients with Breast Cancer.

Purpose: The antibody-drug conjugate (ADC) sacituzumab govitecan (SG) comprises the topoisomerase 1 (TOP1) inhibitor (TOP1i) SN-38, coupled to a monoclonal antibody targeting trophoblast cell surface antigen 2 (TROP-2). Poly(ADP-ribose) polymerase (PARP) inhibition may synergize with TOP1i and SG, but previous studies combining systemic PARP and TOP1 inhibitors failed due to dose-limiting myelosuppression. Here, we assess the proof-of-mechanism and clinical feasibility for SG and talazoparib (TZP) employing an innovative sequential dosing schedule.

Genomic spectrum of actionable alterations in serial cell free DNA (cfDNA) analysis of patients with metastatic breast cancer.

We aimed to study the incidence and genomic spectrum of actionable alterations (AA) detected in serial cfDNA collections from patients with metastatic breast cancer (MBC). Patients with MBC who underwent plasma-based cfDNA testing (Guardant360) between 2015 and 2021 at an academic institution were included. For patients with serial draws, new pathogenic alterations in each draw were classified as actionable alterations (AA) if they met ESCAT I or II criteria of the ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT).

Searching for the "Holy Grail" of breast cancer recurrence risk: a narrative review of the hunt for a better biomarker and the promise of circulating tumor DNA (ctDNA).

Background: This paper is a narrative review of a major clinical challenge at the heart of breast cancer care: determining which patients are at risk of recurrence, which require systemic therapy, and which remain at risk in the survivorship phase of care despite initial therapy.

Methods: We review the literature on prognostic and predictive biomarkers in breast cancer with a focus on detection of minimal residual disease.

Results: While we have many tools to estimate and refine risk that are used to individualize local and systemic therapy, we know that we continue to over treat many patients and undertreat others.

Response-guided neoadjuvant sacituzumab govitecan for localized triple-negative breast cancer: results from the NeoSTAR trial.

Background: Sacituzumab govitecan (SG), a novel antibody-drug conjugate (ADC) targeting TROP2, is approved for pre-treated metastatic triple-negative breast cancer (mTNBC). We conducted an investigator-initiated clinical trial evaluating neoadjuvant (NA) SG (NCT04230109), and report primary results.

Patients And Methods: Participants with early-stage TNBC received NA SG for four cycles.

First-Line Ipatasertib, Atezolizumab, and Taxane Triplet for Metastatic Triple-Negative Breast Cancer: Clinical and Biomarker Results.

Purpose: To evaluate a triplet regimen combining immune checkpoint blockade, AKT pathway inhibition, and (nab-) paclitaxel as first-line therapy for locally advanced/metastatic triple-negative breast cancer (mTNBC).

Patients And Methods: The single-arm CO40151 phase Ib study (NCT03800836), the single-arm signal-seeking cohort of IPATunity130 (NCT03337724), and the randomized phase III IPATunity170 trial (NCT04177108) enrolled patients with previously untreated mTNBC. Triplet therapy comprised intravenous atezolizumab 840 mg (days 1 and 15), oral ipatasertib 400 mg/day (days 1-21), and intravenous paclitaxel 80 mg/m2 (or nab-paclitaxel 100 mg/m2; days 1, 8, and 15) every 28 days.

Virtual Molecular and Precision Medicine Clinic to Improve Access to Clinical Trials for Patients With Metastatic Breast Cancer: An Academic/Community Collaboration.

Purpose: There is a demand for improved care delivery surrounding genomic testing and clinical trial enrollment among patients with metastatic breast cancer (MBC). We sought to improve the current process via real-time informal consultation and prescreening assessment for patients with MBC treated by community and academic medical oncologists by implementing a virtual molecular and precision medicine (vMAP) clinic.

Methods: The vMAP program used a virtual referral system directed to a multidisciplinary team with precision medicine expertise.

Allosteric PI3Kα Inhibition Overcomes On-target Resistance to Orthosteric Inhibitors Mediated by Secondary PIK3CA Mutations.

Unlabelled: PIK3CA mutations occur in ∼8% of cancers, including ∼40% of HR-positive breast cancers, where the PI3K-alpha (PI3Kα)-selective inhibitor alpelisib is FDA approved in combination with fulvestrant. Although prior studies have identified resistance mechanisms, such as PTEN loss, clinically acquired resistance to PI3Kα inhibitors remains poorly understood. Through serial liquid biopsies and rapid autopsies in 39 patients with advanced breast cancer developing acquired resistance to PI3Kα inhibitors, we observe that 50% of patients acquire genomic alterations within the PI3K pathway, including PTEN loss and activating AKT1 mutations.

Stressed target cancer cells drive nongenetic reprogramming of CAR T cells and solid tumor microenvironment.

The poor efficacy of chimeric antigen receptor T-cell therapy (CAR T) for solid tumors is due to insufficient CAR T cell tumor infiltration, in vivo expansion, persistence, and effector function, as well as exhaustion, intrinsic target antigen heterogeneity or antigen loss of target cancer cells, and immunosuppressive tumor microenvironment (TME). Here we describe a broadly applicable nongenetic approach that simultaneously addresses the multiple challenges of CAR T as a therapy for solid tumors. The approach reprograms CAR T cells by exposing them to stressed target cancer cells which have been exposed to the cell stress inducer disulfiram (DSF) and copper (Cu)(DSF/Cu) plus ionizing irradiation (IR).

Feasibility of introducing a smartphone navigation application into the care of breast cancer patients (The FIONA Study).

Purpose: Patients with breast cancer (BC) face complex medical information and decisions. The Outcomes4Me mobile app provides evidence-based BC education, symptom management tracking and clinical trial matching. This study sought to evaluate the feasibility of introducing this app into routine BC care.

Utilizing cell-free DNA to predict risk of developing brain metastases in patients with metastatic breast cancer.

We compared cell-free DNA (cfDNA) results at MBC diagnosis in patients who developed brain metastases (BM) vs those without (non-BM) to understand genomic predictors of BM. Patients with cfDNA testing at MBC diagnosis (Guardant360®, 73 gene next generation sequencing) were identified. Clinical and genomic features of BM and non-BM were compared (Pearson's/Wilcoxon rank sum tests).

Stressed target cancer cells drive nongenetic reprogramming of CAR T cells and tumor microenvironment, overcoming multiple obstacles of CAR T therapy for solid tumors.

The poor efficacy of chimeric antigen receptor T-cell therapy (CAR T) for solid tumor is due to insufficient CAR T cell tumor infiltration, in vivo expansion, persistence, and effector function, as well as exhaustion, intrinsic target antigen heterogeneity or antigen loss of target cancer cells, and immunosuppressive tumor microenvironment (TME). Here we describe a broadly applicable nongenetic approach that simultaneously addresses the multiple challenges of CAR T as a therapy for solid tumors. The approach massively reprograms CAR T cells by exposing them to stressed target cancer cells which have been exposed to the cell stress inducer disulfiram (DSF) and copper (Cu)(DSF/Cu) plus ionizing irradiation (IR).

Therapeutic Role of Tamoxifen for Triple-Negative Breast Cancer: Leveraging the Interaction Between ERβ and Mutant p53.

The absence of effective therapeutic targets and aggressive nature of triple-negative breast cancer (TNBC) renders this disease subset difficult to treat. Although estrogen receptor beta (ERβ) is expressed in TNBC, studies on its functional role have yielded inconsistent results. However, recently, our preclinical studies, along with other observations, have shown the potential therapeutic utility of ERβ in the context of mutant p53 expression.

Adjuvant trastuzumab and vinorelbine for early-stage HER2+ breast cancer.

Background: The single-arm phase II APT trial established trastuzumab and paclitaxel (TH) as the standard adjuvant regimen for small human epidermal growth factor receptor 2 (HER2+) tumors. However, paclitaxel causes alopecia and has high rates of neuropathy and hypersensitivity reactions. In patients with metastatic HER2+ breast cancer (BC), the combination of trastuzumab and vinorelbine (TV) is effective and well tolerated.

Treatment discontinuation, patient-reported toxicities and quality-of-life by age following trastuzumab emtansine or paclitaxel/trastuzumab (ATEMPT).

In the ATEMPT trial, adjuvant trastuzumab emtansine (T-DM1) compared to paclitaxel plus trastuzumab (TH) for stage I HER2-positive breast cancer improved patient-reported outcomes (PROs), while maintaining excellent disease outcomes. We report treatment discontinuation and use multivariable models to compare, patient-reported toxicity and quality-of-life (QOL) by age (≤50, >50) and treatment arm at 18 months post-enrollment among 366 eligible participants randomized in a 3:1 ratio to T-DM1 or TH. T-DM1 discontinuation was higher among women >50 vs.

Immunogenicity of SARS-CoV-2 vaccines in patients with breast cancer.

Purpose: To explore the immunogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in patients with breast cancer based on type of anticancer treatment.

Methods: Patients with breast cancer had anti-spike antibody concentrations measured ⩾14 days after receiving a full SARS-CoV-2 vaccination series. The primary endpoint was IgA/G/M anti-spike antibody concentration.

Neoadjuvant study of niraparib in patients with HER2-negative, BRCA-mutated, resectable breast cancer.

This single-arm pilot study (NCT03329937) evaluated neoadjuvant niraparib antitumor activity and safety in patients with localized HER2-negative, BRCA-mutated breast cancer. Twenty-one patients received niraparib 200 mg once daily in 28-day cycles. After 2 cycles, tumor response (≥30% reduction from baseline) by MRI was 90.