A phase 1b study of zilovertamab in combination with paclitaxel for locally advanced/unresectable or metastatic Her2-negative breast cancer.

BACKGROUND: Zilovertamab is a humanized monoclonal antibody targeting ROR1, an onco-embryonic antigen expressed by malignant cells of a variety of solid tumors, including breast cancer. A prior phase 1 study showed that zilovertamab was well tolerated and effective in inhibiting ROR1-signaling, which leads to activation of ERK1/2, NF-κB, and NRF2 target genes. This phase 1b study evaluated the safety and tolerability of zilovertamab with paclitaxel in patients with advanced breast cancer. PATIENTS AND METHODS: Eligible patients had locally advanced, unresectable, or metastatic HER2- breast cancer with Eastern Cooperative Group performance status of 0-2 and without prior taxane therapy in the advanced setting. Study treatment included 600 mg of zilovertamab administered intravenously (IV) on Days 1 and 15 of Cycle 1 and then Day 1 of each 28-day cycle along with paclitaxel weekly at 80 mg/m2 IV. RESULTS: Study patients had received a median of 4 prior therapies (endocrine therapy + chemotherapy) for locally advanced, unresectable, or metastatic disease. No patient discontinued therapy due to toxicity ascribed to zilovertamab. Adverse events were consistent with the known safety profile of paclitaxel. Of 16 patients, 6 (38%) had a partial response, and 6/16 (38%) patients had stable disease as best tumor response. CONCLUSION: The combination of zilovertamab and paclitaxel was safe and well tolerated in heavily pre-treated advanced breast cancer patients. Further evaluation of ROR1 targeting in breast cancer patients with zilovertamab is warranted. TRIAL REGISTRATION: NCT02776917. Registered on ClinicalTrials.gov on 05/17/2016.

NSABP FB-10: a phase Ib/II trial evaluating ado-trastuzumab emtansine (T-DM1) with neratinib in women with metastatic HER2-positive breast cancer.

BACKGROUND: We previously reported our phase Ib trial, testing the safety, tolerability, and efficacy of T-DM1 + neratinib in HER2-positive metastatic breast cancer patients. Patients with ERBB2 amplification in ctDNA had deeper and more durable responses. This study extends these observations with in-depth analysis of molecular markers and mechanisms of resistance in additional patients. METHODS: Forty-nine HER2-positive patients (determined locally) who progressed on-treatment with trastuzumab + pertuzumab were enrolled in this phase Ib/II study. Mutations and HER2 amplifications were assessed in ctDNA before (C1D1) and on-treatment (C2D1) with the Guardant360 assay. Archived tissue (TP0) and study entry biopsies (TP1) were assayed for whole transcriptome, HER2 copy number, and mutations, with Ampli-Seq, and centrally for HER2 with CLIA assays. Patient responses were assessed with RECIST v1.1, and Molecular Response with the Guardant360 Response algorithm. RESULTS: The ORR in phase II was 7/22 (32%), which included all patients who had at least one dose of study therapy. In phase I, the ORR was 12/19 (63%), which included only patients who were considered evaluable, having received their first scan at 6 weeks. Central confirmation of HER2-positivity was found in 83% (30/36) of the TP0 samples. HER2-amplified ctDNA was found at C1D1 in 48% (20/42) of samples. Patients with ctHER2-amp versus non-amplified HER2 ctDNA determined in C1D1 ctDNA had a longer median progression-free survival (PFS): 480 days versus 60 days (P = 0.015). Molecular Response scores were significantly associated with both PFS (HR 0.28, 0.09-0.90, P = 0.033) and best response (P = 0.037). All five of the patients with ctHER2-amp at C1D1 who had undetectable ctDNA after study therapy had an objective response. Patients whose ctHER2-amp decreased on-treatment had better outcomes than patients whose ctHER2-amp remained unchanged. HER2 RNA levels show a correlation to HER2 CLIA IHC status and were significantly higher in patients with clinically documented responses compared to patients with progressive disease (P = 0.03). CONCLUSIONS: The following biomarkers were associated with better outcomes for patients treated with T-DM1 + neratinib: (1) ctHER2-amp (C1D1) or in TP1; (2) Molecular Response scores; (3) loss of detectable ctDNA; (4) RNA levels of HER2; and (5) on-treatment loss of detectable ctHER2-amp. HER2 transcriptional and IHC/FISH status identify HER2-low cases (IHC 1+ or IHC 2+ and FISH negative) in these heavily anti-HER2 treated patients. Due to the small number of patients and samples in this study, the associations we have shown are for hypothesis generation only and remain to be validated in future studies. Clinical Trials registration NCT02236000.

Prognostic value of baseline neutrophil/lymphocyte ratio in HER2-positive metastatic breast cancer: exploratory analysis of data from the CLEOPATRA trial.

PURPOSE: This study aimed to evaluate the prognostic role of the baseline neutrophil/lymphocyte ratio (NLR) in HER2-positive metastatic breast cancer (MBC) patients treated with trastuzumab/pertuzumab. EXPERIMENTAL DESIGN: Data from 780 patients from the CLEOPATRA trial and 248 local patients were collected. Patients were divided into the low and high NLR subgroups by the NLR cutoff value. Propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) methods were used to control bias. Associations between the NLR and progression-free survival (PFS) and overall survival (OS) were analyzed. RESULTS: The baseline characteristics of the subgroups were well balanced after PSM and IPTW. A low baseline NLR was associated with better PFS and OS in the trastuzumab and docetaxel (TH) group in the unadjusted, PSM and IPTW models. After IPTW, a low NLR, versus a high NLR, was associated with improved PFS (HR 1.35, 95% CI 1.07-1.70, P = 0.012) and OS (HR 1.47, 95% CI 1.12-1.94, P = 0.006) in the TH group. In patients undergoing treatment with trastuzumab and pertuzumab and docetaxel (THP), a low baseline NLR was also correlated with better PFS but not OS across the three models. After IPTW, a low NLR was associated with better PFS (HR 1.52, 95% CI 1.20-1.93, P = 0.001) than a high NLR in the THP group. Multivariate analyses showed that a low baseline NLR was a predictor for PFS and OS in the TH group and for PFS in the THP group in all three models. In the real-world setting, a low baseline NLR was a predictor of better PFS among patients treated with docetaxel plus trastuzumab without or with pertuzumab in the multivariate model (P = 0.015 and 0.008, respectively). CONCLUSIONS: A low baseline NLR is associated with better survival outcomes among HER2-positive MBC patients receiving docetaxel plus trastuzumab/pertuzumab as first-line therapy.

c-MET-positive circulating tumor cells and cell-free DNA as independent prognostic factors in hormone receptor-positive/HER2-negative metastatic breast cancer.

BACKGROUND: Endocrine therapy resistance in hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) is a significant clinical challenge that poses several unmet needs in the management of the disease. This study aimed to investigate the prognostic value of c-MET-positive circulating tumor cells (cMET+ CTCs), ESR1/PIK3CA mutations, and cell-free DNA (cfDNA) concentrations in patients with hormone receptor-positive (HR+) metastatic breast cancer (mBC). METHODS: Ninety-seven patients with HR+ mBC were prospectively enrolled during standard treatment at Samsung Medical Center. CTCs were isolated from blood using GenoCTC® and EpCAM or c-MET CTC isolation kits. PIK3CA and ESR1 hotspot mutations were analyzed using droplet digital PCR. CfDNA concentrations were calculated using internal control copies from the ESR1 mutation test. Immunocytochemistry was performed to compare c-MET overexpression between primary and metastatic sites. RESULTS: The proportion of c-MET overexpression was significantly higher in metastatic sites than in primary sites (p = 0.00002). Survival analysis showed that c-MET+ CTC, cfDNA concentration, and ESR1 mutations were significantly associated with poor prognosis (p = 0.0026, 0.0021, and 0.0064, respectively) in HR+/HER2- mBC. By contrast, EpCAM-positive CTC (EpCAM+ CTC) and PIK3CA mutations were not associated with progression-free survival (PFS) in HR+/HER2- mBC. Multivariate analyses revealed that c-MET+ CTCs and cfDNA concentration were independent predictors of PFS in HR+/HER2- mBC. CONCLUSIONS: Monitoring c-MET+ CTC, rather than assessing c-MET expression in the primary BC site, could provide valuable information for predicting disease progression, as c-MET expression can change during treatment. The c-MET+ CTC count and cfDNA concentration could provide complementary information on disease progression in HR+ /HER2- mBC, highlighting the importance of integrated liquid biopsy.

Clinical efficacy of tumor organoid-guided cancer therapy for locally advanced unresectable or metastatic breast cancer.

Patient-derived organoids (PDOs) may facilitate treatment selection. This retrospective cohort study evaluated the feasibility and clinical benefit of using PDOs to guide personalized treatment in metastatic breast cancer (MBC). Patients diagnosed with MBC were recruited between January 2019 and August 2022. PDOs were established and the efficacy of customized drug panels was determined by measuring cell mortality after drug exposure. Patients receiving organoid-guided treatment (OGT) were matched 1:2 by nearest neighbor propensity scores with patients receiving treatment of physician's choice (TPC). The primary outcome was progression-free survival. Secondary outcomes included objective response rate and disease control rate. Targeted gene sequencing and pathway enrichment analysis were performed. Forty-six PDOs (46 of 51, 90.2%) were generated from 45 MBC patients. PDO drug screening showed an accuracy of 78.4% (95% CI 64.9%-91.9%) in predicting clinical responses. Thirty-six OGT patients were matched to 69 TPC patients. OGT was associated with prolonged median progression-free survival (11.0 months vs. 5.0 months; hazard ratio 0.53 [95% CI 0.33-0.85]; p = .01) and improved disease control (88.9% vs. 63.8%; odd ratio 4.26 [1.44-18.62]) compared with TPC. The objective response rate of both groups was similar. Pathway enrichment analysis in hormone receptor-positive, human epidermal growth factor receptor 2-negative patients demonstrated differentially modulated pathways implicated in DNA repair and transcriptional regulation in those with reduced response to capecitabine/gemcitabine, and pathways associated with cell cycle regulation in those with reduced response to palbociclib. Our study shows that PDO-based functional precision medicine is a feasible and effective strategy for MBC treatment optimization and customization.

Real-world treatment patterns for palbociclib plus an aromatase inhibitor, or an aromatase inhibitor alone, for patients with metastatic breast cancer in the Flatiron Database.

There are limited real-world comparative effectiveness data for palbociclib plus an aromatase inhibitor (AI) as a first-line (1L) treatment examining endpoints that require long term follow-up and post 1L progression. The Flatiron Health Analytic Database was used to characterize treatment and dosing patterns in patients with hormone receptor-positive/human epidermal growth factor 2-negative (HR+/HER2-) metastatic breast cancer (mBC) receiving palbociclib plus an AI vs an AI alone in routine US clinical practice. In addition, time to chemotherapy (TTC) and real-world progression-free survival (rwPFS) when combining 1L and second-line of therapy (rwPFS2) were assessed. Of 1324 patients who received palbociclib plus an AI between February 3, 2015 and March 31, 2020, 1110 (83.8%) started palbociclib at the recommended 125 mg/day dose. After stabilized inverse probability treatment-weighting (sIPTW), median TTC in patients treated with palbociclib plus an AI and AI alone was 37.4 months (95% confidence interval [CI], 33.7-40.7) and 29.2 months (95% CI, 26.8-33.5), respectively (hazard ratio [HR] = 0.77 [95% CI, 0.69-0.86], P < .0001); median rwPFS2 was 32.6 months (95% CI, 29.4-35.2) and 20.7 months (95% CI, 18.9-22.6), respectively (HR = 0.62 [95% CI, 0.54-0.70], P < .0001). Sensitivity analyses with propensity score matching showed similar results to sIPTW analyses. Results from this large real-world study examining additional effectiveness outcomes beyond 1L rwPFS and overall survival support the use of palbociclib plus an AI as a 1L treatment for patients with HR+/HER2- mBC.

Medicinal Mushrooms in Metastatic Breast Cancer: What Is Their Therapeutic Potential as Adjuvant in Clinical Settings?

Breast cancer (BC) is the most commonly diagnosed tumor, remaining one of the leading causes of morbidity and mortality in females worldwide, with the highest rates in Western countries. Among metastatic BC (MBC), triple-negative breast cancer (TNBC) is characterized by the lack of expression of specific receptors, and differs from other subgroups of BC for its increased growth and fast spreading, with reduced treatment possibilities and a worse outcome. Actually, MBC patients are extremely prone to metastasis and consequent relapses, which affect distant target organs (e.g., brain, lung, bone and liver). Hence, the comprehension of biological mechanisms underlying the BC metastatization process is a key requirement to conceive/set up innovative medicinal strategies, with the goal to achieve long-lasting therapeutic efficacy, reducing adverse effects, and also ameliorating Quality of Life (QoL). Bioactive metabolites isolated from medicinal mushrooms (MMs) used as a supportive treatment, combined with conventional oncology, have recently gained wide interest. In fact, mounting evidence has revealed their peculiar promising immunomodulatory, anti-inflammatory and anticancer activities, even though these effects have to be further clarified. Among the group of most promising MMs are Lentinula edodes, Grifola frondosa, Ganoderma lucidum, Ophiocordyceps sinensis and Agaricus blazei, which are already employed in conventional cancer protocols in Asia and China. Recently, a growing number of studies have focused on the pharmacology and feasibility of MM-derived bioactive compounds as a novel valuable approach to propose an effective adjuvant therapy for MBC patients' management. In this review, we summarized the current state of knowledge on the abovementioned MM-derived bioactive compounds and their therapeutic potential in clinical settings.

Efficacy and safety of nanoparticle albumin-bound paclitaxel in taxane-pretreated metastatic breast cancer patients.

BACKGROUND: Taxanes are the basic components of breast cancer chemotherapy. Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) shows improved antitumor effects because of more targeted delivery. However, the effects of nab-paclitaxel have not been systematically studied in patients with metastatic breast cancer (MBC) pretreated with taxanes. Considering the limited treatment options for MBC, this study retrospectively evaluated the clinical efficacy and adverse effects of nab-paclitaxel in patients with taxane-pretreated MBC. METHODS: Patients who had previously received taxanes and subsequently received nab-paclitaxel chemotherapy for MBC at Jiangsu Cancer Hospital between October 2014 and April 2022 were included for analysis. The primary end point was progression-free survival (PFS), and the secondary end points were the objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR), and side effects. RESULTS: A total of 236 female patients with MBC were included. The median PFS was 7.20 months (95% confidence interval [CI], 6.63-7.80 months), and the ORR, DCR, and CBR were 29.55% (95% CI, 23.50%-35.60%), 83.64% (95% CI, 78.70%-88.60%), and 56.36% (95% CI, 49.80%-63.00%), respectively. Following nab-paclitaxel treatment, the median PFS of patients who were sensitive to taxanes during previous treatments was significantly longer than that of patients who were resistant to taxanes (7.57 months vs. 4.43 months, p < .001). The most common adverse events were sensory neuropathy (89.83%), neutropenia (48.73%), leukopenia (46.61%), and anemia (35.59%). CONCLUSION: Nab-paclitaxel demonstrated clinical activity in taxane-pretreated patients with MBC. This beneficial effect was observed both in patients who were sensitive and resistant to taxanes during previous treatments. These results suggest nab-paclitaxel as the preferred chemotherapy regimen in patients with MBC, regardless of their sensitivity to taxanes during previous treatments.

Palliative Care Interventions and End-of-Life Care for Patients with Metastatic Breast Cancer: A Multicentre Analysis.

BACKGROUND: The aim of this study was to describe the implementation of integrated palliative care (PC) and the intensity of care in the last 3 months before death for patients with metastatic breast cancer. MATERIALS AND METHODS: We conducted a multicentric study of all adult patients with metastatic breast cancer who died over a 4-month period. Complete data were collected and checked from clinical records, including PC interventions and criteria regarding EOL care aggressiveness. RESULTS: A total of 340 decedent patients from 12 comprehensive cancer centres in France were included in the study. Sixty-five percent met the PC team with a median time of 39 days between the first intervention and death. In the last month before death, 11.5% received chemotherapy, the frequency of admission to intensive care unit was 2.4%, and 83% experienced acute hospitalization. The place of death was home for 16.7%, hospitalization for 63.3%, PC unit for 20%. Univariate and multivariate analyses showed factors independently associated with a higher frequency of chemotherapy in the last month before death: having a dependent person at home, meeting for the first time with a PC team < 30 days before death, and time between the first metastasis and death below the median. CONCLUSION: PC team integration was frequent and late for patients with metastatic breast cancer. However, PC intervention > 30 days is associated with less chemotherapy in the last month before death. Further studies are needed to better understand how to implement a more effective mode of PC integration for patients with metastatic breast cancer.

Ribociclib-Induced Cutaneous Adverse Events in Metastatic HR+/HER2- Breast Cancer: Incidence, Multidisciplinary Management, and Prognostic Implication.

BACKGROUND: Ribociclib is approved for hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer (ABC) treatment, in combination with endocrine therapy. Hematological, hepatic, and cardiac adverse events (AEs) emerged from pivotal trials, but little is known about cutaneous adverse events (CAEs). PATIENTS AND METHODS: We report data from a retrospective cohort study of all patients with HR+/HER2- ABC treated with ribociclib at Humanitas Cancer Center between June 2017 and December 2022. We recorded clinical-pathological data, the incidence, and treatment of ribociclib-related CAEs. These were evaluated according to the NCI-CTCAE v5.0 classification. Progression-free survival (PFS) was estimated by Kaplan-Meier method and the log-rank test was used to analyze differences between groups. RESULTS: Thirteen of 91 patients (14.3%) experienced treatment-related CAEs (mean time to the occurrence: 3.9 months). The most frequent CAEs were eczematous dermatitis (53.8%) and maculo-papular reaction (15.4%). Itch was reported by all 13 patients. The grade was G3 in 8 cases, G2 in 4, and G1 in 1. An integrated approach based on ribociclib dose modulation and dermatological interventions (oral antihistamine, moisturized cream, topical, and/or systemic steroids) could prevent ribociclib discontinuation in most patients. At a median follow-up of 20 months, the median PFS was 13 months (range, 1-66) with a better PFS curves for patients experiencing CAEs (P = .04). CONCLUSION: We mapped frequency and types of ribociclib-induced CAEs. An interdisciplinary management of CAEs incorporated into routine care may reduce the rate of drug discontinuation thus potentially contributing to better long-term outcomes.

Optimal Sequential Strategies for Antibody-Drug Conjugate in Metastatic Breast Cancer: Evaluating Efficacy and Cross-Resistance.

BACKGROUND: The optimal sequential strategy for antibody-drug conjugates (ADCs) in breast cancer remains uncertain. This study aimed to evaluate the efficacy and potential resistance of second ADC (ADC2) following the first ADC (ADC1) in human epidermal growth factor receptor 2 (HER2)-positive and HER2-low MBC. METHODS: This retrospective, multicenter, real-world study enrolled patients with MBC who received at least 2 different types of ADCs in 3 hospitals in China between July 1, 2017 and May 1, 2023. Outcomes included the objective response rate (ORR) for ADC1 and ADC2, progression free survival 2 (PFS2), defined as the time from initiation of ADC2 to progression, and overall survival (OS). RESULTS: Seventy-nine female patients were included, 64 of whom had HER2-positive disease. The ORR for ADC2 with similar payload of ADC1 was found to be 5.3%. When switching to a different payload, the ORR of ADC2 increased to 22.6%. The PFS2 for ADC2 remained similar regardless of whether the payload was similar or different. Switching to different payload showed a higher ORR in patients with rapid progression and a durable response longer than 6 months (41.2% vs 15.0%). Specifically, significantly longer PFS2 and OS were seen in patients treated with trastuzumab deruxtecan (T-Dxd) compared to those treated with disitamab vedotin (RC48) after progression from trastuzumab emtansine (T-DM1; median PFS2 5.37 months vs 3.30 months, HR = 0.40, 95% CI 0.17-0.93, P = .034; median OS 50.6 months vs 20.2 months, HR = 0.27, 95% CI 0.08-0.91, P = .034). For patients who progressed after T-Dxd, the median PFS2 was 6.05 months for those treated with RC48 versus 0.93 months for those treated with T-DM1 (HR = 0.03, 95% CI 0.002-0.353, P = .0093). Genomic analysis revealed that alternation of retinoblastoma1 was significantly associated with superior PFS. CONCLUSION: The alternation of payload achieves different responses in different settings. T-Dxd followed by RC48 may be a potentially beneficial strategy in HER2-positive disease. Further research is needed to elucidate the mechanism of cross-resistance.

Health-related quality of life with sacituzumab govitecan in HR+/HER2- metastatic breast cancer in the phase III TROPiCS-02 trial.

BACKGROUND: The TROPiCS-02 study (NCT03901339) demonstrated that sacituzumab govitecan (SG) has superior clinical outcomes over treatment of physician's choice (TPC) chemotherapy in patients with hormone receptor-positive, human epidermal growth factor 2 receptor-negative (HR+/HER2-) metastatic breast cancer (mBC). Here, we present health-related quality of life (HRQoL) patient-reported outcome (PRO) findings from this study. PATIENTS AND METHODS: Eligible adults with HR+/HER2- mBC who previously received a taxane, endocrine-based therapy, a CDK4/6 inhibitor, and 2-4 lines of chemotherapy were randomized 1:1 to receive SG or TPC until progression or unacceptable toxicity. PROs were assessed at baseline and on day 1 of each cycle, using the European Organization for Research and Treatment of Cancer Quality-of-Life Core 30 (EORTC QLQ-C30), EQ-5D-5L, and PRO Common Terminology Criteria for Adverse Events (PRO-CTCAE). RESULTS: Compared to TPC, overall least square mean change from baseline was significantly better for SG for physical functioning and dyspnea, but worse for diarrhea. Time to first clinically meaningful worsening or death was significantly longer for SG in global health status/quality of life, physical functioning, fatigue, emotional functioning, dyspnea, insomnia, and financial difficulties of the EORTC QLQ-C30 and the EQ-VAS, but longer for TPC in diarrhea. Few patients in both arms reported experiencing any worsening to level 3 or 4 treatment-related symptomatic events during treatment, as assessed by 16 PRO-CTCAE items, except for diarrhea frequency and amount of hair loss, which favored TPC. CONCLUSIONS: SG was associated with an HRQoL benefit in most symptoms and functioning, compared with TPC. This supports the favorable profile of SG as a treatment option for patients with pretreated HR+/HER2- mBC.

Trastuzumab deruxtecan in previously treated patients with HER2-positive metastatic breast cancer: updated survival results from a phase II trial (DESTINY-Breast01).

BACKGROUND: Primary analysis of the multicenter, open-label, single-arm, phase II DESTINY-Breast01 trial (median follow-up 11.1 months) demonstrated durable antitumor activity with trastuzumab deruxtecan (T-DXd) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC) previously treated with trastuzumab emtansine (T-DM1). We report updated cumulative survival outcomes with a median follow-up of 26.5 months (data cut-off 26 March 2021). PATIENTS AND METHODS: Patients with HER2-positive mBC resistant or refractory to T-DM1 received T-DXd 5.4 mg/kg intravenously every 3 weeks until disease progression, unacceptable adverse events, or withdrawal of consent. The primary endpoint was confirmed objective response rate (ORR) by independent central review (ICR). Secondary endpoints included overall survival (OS), duration of response (DoR), progression-free survival (PFS), and safety. RESULTS: The ORR by ICR was 62.0% [95% confidence interval (CI) 54.5% to 69.0%] in patients who received T-DXd 5.4 mg/kg every 3 weeks (n = 184). Median OS was 29.1 months (95% CI 24.6-36.1 months). Median PFS and DoR were 19.4 months (95% CI 14.1-25.0 months) and 18.2 months (95% CI 15.0 months-not evaluable), respectively. Drug-related treatment-emergent adverse events (TEAEs) were observed in 183 patients (99.5%), and 99 patients (53.8%) had one or more grade ≥3 TEAEs. Adjudicated drug-related interstitial lung disease/pneumonitis occurred in 15.8% of patients (n = 29), of which 2.7% (n = 5) were grade 5. CONCLUSIONS: These updated results provide further evidence of sustained antitumor activity of T-DXd with a consistent safety profile in heavily pretreated patients with HER2-positive mBC.

Laminin I mediates resistance to lapatinib in HER2-positive brain metastatic breast cancer cells in vitro.

The role of extracellular matrix (ECM) prevalent in the brain metastatic breast cancer (BMBC) niche in mediating cancer cell growth, survival, and response to therapeutic agents is not well understood. Emerging evidence suggests a vital role of ECM of the primary breast tumor microenvironment (TME) in tumor progression and survival. Possibly, the BMBC cells are also similarly influenced by the ECM of the metastatic niche; therefore, understanding the effect of the metastatic ECM on BMBC cells is imperative. Herein, we assessed the impact of various ECM components (i.e., Tenascin C, Laminin I, Collagen I, Collagen IV, and Fibronectin) on brain metastatic human epidermal growth factor receptor 2 (HER2)-positive and triple negative breast cancer (TNBC) cell lines in vitro. The highly aggressive TNBC cell line was minimally affected by ECM components exhibiting no remarkable changes in viability and morphology. On the contrary, amongst various ECM components tested, the HER2-positive cell line was significantly affected by Laminin I with higher viability and demonstrated a distinct spread morphology. In addition, HER2-positive BMBC cells exhibited resistance to Lapatinib in presence of Laminin I. Mechanistically, Laminin I-induced resistance to Lapatinib was mediated in part by phosphorylation of Erk 1/2 and elevated levels of Vimentin. Laminin I also significantly enhanced the migratory potential and replicative viability of HER2-positive BMBC cells. In sum, our findings show that presence of Laminin I in the TME of BMBC cells imparts resistance to targeted therapeutic agent Lapatinib, while increasing the possibility of its dispersal and clonogenic survival.

A phase Ib/II study of eribulin in combination with cyclophosphamide in patients with advanced breast cancer.

PURPOSE: We hypothesized that eribulin combined with cyclophosphamide (EC) would be an effective combination with tolerable toxicity for the treatment of advanced breast cancer (ABC). METHODS: Patients with histologically confirmed metastatic or unresectable ABC with any number of prior lines of therapy were eligible to enroll. In the dose escalation cohort, dose level 0 was defined as eribulin 1.1 mg/m2 and cyclophosphamide 600 mg/m2, and dose level 1 was defined as eribulin 1.4 mg/m2 and cyclophosphamide 600 mg/m2. Eribulin was given on days 1 and 8 and cyclophosphamide on day 1 of a 21-day cycle. In the dose expansion cohort, enrollment was expanded at dose level 1. The primary objective was clinical benefit rate (CBR), and secondary objectives were response rate (RR), duration of response (DOR), progression-free survival (PFS), and safety. RESULTS: No dose-limiting toxicities were identified in the dose escalation cohort (n = 6). In the dose expansion cohort, an additional 38 patients were enrolled for a total of 44 patients, including 31 patients (70.4%) with hormone receptor-positive (HR +)/HER2- disease, 12 patients (27.3%) with triple-negative breast cancer (TNBC), and 1 patient (2.3%) with HR + /HER2 + disease. Patients had a median age of 56 years (range 33-82 years), 1 prior line of hormone therapy (range 0-6), and 2 prior lines of chemotherapy (range 0-7). CBR was 79.5% (35/44; 7 partial response, 28 stable disease) and the median DOR was 16.4 weeks (range 13.8-21.1 weeks). Median PFS was 16.4 weeks (95% CI: 13.8-21.1 weeks). The most common grade 3/4 adverse event was neutropenia (47.7%, n = 21). Fourteen of 26 patients (53.8%) with circulating tumor cell (CTC) data were CTC-positive ([Formula: see text] 5 CTC/7.5 mL) at baseline. Median PFS was shorter in patients who were CTC-positive vs. negative (13.1 vs 30.6 weeks, p = 0.011). CONCLUSION: In heavily pretreated patients with ABC, treatment with EC resulted in an encouraging CBR of 79.5% and PFS of 16.4 weeks, which compares favorably to single-agent eribulin. Dose reduction and delays were primarily due to neutropenia. The contribution of cyclophosphamide to eribulin remains unclear but warrants further evaluation. NCT01554371.

A randomized phase II study of metronomic cyclophosphamide and methotrexate (CM) with or without bevacizumab in patients with advanced breast cancer.

PURPOSE: Metronomic chemotherapy has the potential to offer tumor control with reduced toxicity when compared to standard dose chemotherapy in patients with metastatic breast cancer. As metronomic chemotherapy may target the tumor microvasculature, it has the potential for synergistic effects with antiangiogenic agents such as the VEGF-A inhibitor bevacizumab. METHODS: In this randomized phase II study, patients with metastatic breast cancer were randomized to receive metronomic oral cyclophosphamide and methotrexate (CM) combined with bevacizumab (Arm A) or CM alone (Arm B). The primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety and tolerability. RESULTS: A total of 55 patients were enrolled, with 34 patients treated on Arm A and 21 patients treated on Arm B. The ORR was modestly higher in Arm A (26%) than in Arm B (10%); neither met the 40% cutoff for further clinical evaluation. The median time to progression (TTP) was 5.52 months (3.22-13.6) on Arm A and 1.82 months (1.54-6.70) on Arm B (log-rank p = 0.008). The median OS was 29.6 months (17.2-NA) on Arm A and 16.2 months (15.7-NA) on Arm B (log-rank p = 0.7). Common all-grade adverse events in both arms included nausea, fatigue, and elevated AST. CONCLUSION: The combination of metronomic CM with bevacizumab significantly improved PFS over CM alone, although there was no significant difference in OS. Oral metronomic chemotherapy alone has limited activity in advanced breast cancer. CLINICALTRIALS: gov Identifier: NCT00083031. Date of Registration: May 17, 2004.

Demographic and clinical characteristics of patients with metastatic breast cancer and leptomeningeal disease: a single center retrospective cohort study.

PURPOSE: Leptomeningeal disease (LMD) is a devastating complication of metastatic breast cancer (MBC). It is critical to better understand the risk factors, natural history, and treatment outcomes, including patients in a modern cohort. METHODS: In this single center retrospective cohort study, we identified patients with MBC and LMD who received care from 2000 to 2024 and abstracted key clinical, treatment, and survival data. RESULTS: We identified 111 patients with MBC and LMD, including patients with the following subtypes: HR+/HER2- (n = 53, 47.7%), HER2+ (n = 30, 27.0%), and triple negative breast cancer (TNBC; n = 28, 25.2%). Median time from the diagnosis of MBC to LMD was 16.4 months (range 0-101.3 months). After the diagnosis of LMD, most patients received systemic therapy (n = 66, 59.5%) and/or central nervous system (CNS)-directed therapy (n = 94, 84.7%) including intrathecal therapy (n = 42, 37.8%) and/or CNS-directed radiation therapy (n = 70, 63.1%). In all patients, median overall survival (OS) from the diagnosis of LMD to death was 4.1 months (range 0.1-78.1 months) and varied by subtype, with HR+/HER2- or HER2+ MBC patients living longer than those with TNBC (4.2 and 6.8 months respectively vs. 2.0 months, p < 0.01, HR 2.15, 95% CI 1.36-3.39). Patients who received CNS-directed therapy lived longer than those who did not (4.2 vs. 1.3, p = 0.02 HR 0.54, 0.32-0.91). Patients diagnosed with LMD from 2015 to 2024 lived longer than those diagnosed from 2000 to 2014 (6.4 vs. 2.9 months, p = 0.04, HR 0.67, 95% CI 0.46-0.99). On multivariable analysis, having TNBC was associated with shorter OS from time of LMD to death (p = 0.004, HR 2.03, 95% CI 1.25-3.30). CONCLUSION: This is one of the largest case series of patients with MBC and LMD. Patients diagnosed with LMD from 2015 to 2024 lived longer than those diagnosed from 2000 to 2014, although median OS was short overall. Patients with TNBC and LMD had particularly short OS. Novel therapeutic strategies for LMD remain an area of unmet clinical need.

Disparities in PI3K/mTOR inhibitor use, toxicities, and outcomes among patients with metastatic breast cancer.

PURPOSE: Novel agents such as PI3K and mTOR inhibitors (PI3K/mTORi) have expanded treatment options in metastatic breast cancer (MBC). Nevertheless, mortality rates remain disproportionately high for Black patients and patients with lower socioeconomic status. Furthermore, clinical trials for these novel agents lacked diversity, so their toxicity profile in minority populations is uncertain. METHODS: We conducted a retrospective analysis of EHR-derived data from the Flatiron Health Database for patients with HR+, HER2- MBC. Multivariable logistic regression was used to evaluate factors associated with PI3K/mTORi use and toxicity outcomes. RESULTS: A total of 9169 patients with MBC were included in our analysis, of which 1780 (19.4%) received a PI3K/mTORi. We estimated the conditional total effect of insurance through Medicaid, and found lower odds of use of PI3K/mTORi among patients on Medicaid compared to those with commercial insurance (OR 0.73, 95% CI 0.54-0.99, p = 0.049). Odds of PI3K/mTORi use were higher for patients treated at an academic center (OR 1.28, CI 1.06-1.55, p = 0.01). Modeled as a controlled direct effect, Black/African American (Black/AA) race had no impact on odds of PI3K/mTOR use. Black/AA patients had twice the odds of developing hyperglycemia on PI3K/mTORi compared to White patients (OR 2.02, CI 1.24-3.39, p < 0.01). CONCLUSION: This analysis of real-world data suggests that the use of PI3K/mTORi is influenced by socioeconomic factors. We also found racial disparities in toxicity outcomes, with Black/AA patients having twice the risk of hyperglycemia. Our findings call for greater efforts to ensure access to novel treatments and improve their tolerability in diverse populations.

Survival analysis of patients with brain metastases at initial breast cancer diagnosis over the last decade.

PURPOSE: There have been significant advances in the treatment of metastatic breast cancer (BC) over the past years, and long-term outcomes after a diagnosis of brain metastases are lacking. We aimed to identify predictors of brain metastases at initial breast cancer diagnosis, describe overall survival (OS) in the past decade, and identify factors associated with OS after brain metastases diagnosis. METHODS: We evaluated patients with de novo stage IV BC using the Surveillance, Epidemiology and End Results database from 2010 to 2019. Multivariate logistic regression was conducted to assess predictors of brain metastases at initial breast cancer diagnosis. OS was estimated using the Kaplan-Meier method and log rank test was used to compare differences between groups. Cox regression was used to assess associations between several variables and OS. RESULTS: 1,939 patients with brain metastases at initial breast cancer diagnosis were included. Factors associated with this presentation were grade III/IV tumors, ductal histology, hormone receptor (HR)-negative/human epidermal growth factor receptor 2 (HER2)-positive subtype, and extracranial metastases. Patients with HR-positive/HER2-positive disease had the longest OS (median 18 months) and 12.2% were alive at 8 years. Factors associated with shorter OS included older age, lower income, triple-negative subtype, higher grade, and visceral metastases. CONCLUSION: Over the last decade, the median OS of patients with brain metastases at initial breast cancer diagnosis remained poor; however, a substantial minority survive 5 or more years, with rates higher in patients with HER2-positive tumors. In addition to tumor subtype, OS varied according to age, extracranial metastases, and sociodemographic factors.

Everolimus plus endocrine therapy beyond CDK4/6 inhibitors progression for HR+ /HER2- advanced breast cancer: a real-world evidence cohort.

PURPOSE: Everolimus in combination with endocrine therapy (ET) was formerly approved as 2nd-line therapy in HR(+)/HER2(-) advanced breast cancer (aBC) patients (pts) progressing during or after a non-steroidal aromatase inhibitor (NSAI). Since this approval, the treatment landscape of aBC has changed dramatically, particularly with the arrival of CDK 4-6 inhibitors. Endocrine monotherapy after progression to CDK4/6 inhibitors has shown a limited progression-free survival (PFS), below 3 months. Evidence of the efficacy of everolimus plus ET after CDK4/6 inhibitors is scarce. METHODS: A retrospective observational study of patients with aBC treated with everolimus and ET beyond CDK4/6-i progression compiled from February 2015 to December 2022 in 4 Spanish hospitals was performed. Clinical and demographic data were collected from medical records. The main objective was to estimate the median progression-free survival (mPFS). Everolimus adverse events (AE) were registered. Quantitative variables were summarized with medians; qualitative variables with proportions and the Kaplan-Meier method were used for survival estimates. RESULTS: One hundred sixty-one patients received everolimus plus ET (exemestane: 96, fulvestrant: 54, tamoxifen: 10, unknown: 1) after progressing on a CDK4/6 inhibitor. The median follow-up time was 15 months (interquartile range: 1-56 months). The median age at diagnosis was 49 years (range: 35-90 years). The estimated mPFS was 6.0 months (95%CI 5.3-7.8 months). PFS was longer in patients with previous CDK4/6 inhibitor therapy lasting for > 18 months (8.7 months, 95%CI 6.6-11.3 months), in patients w/o visceral metastases (8.0 months, 95%CI 5.8-10.5 months), and chemotherapy-naïve in the metastatic setting (7.2 months, 95%CI 5.9-8.4 months). CONCLUSION: This retrospective analysis cohort of everolimus plus ET in mBC patients previously treated with a CDK4/6 inhibitor suggests a longer estimated mPFS when compared with the mPFS with ET monotherapy obtained from current randomized clinical data. Everolimus plus ET may be considered as a valid control arm in novel clinical trial designs.