Treatment Of Metastatic Breast Cancer Research Articles

Abstract A001: Analytical validation of a novel multiomic metastatic breast cancer liquid biopsy test that combines ctDNA analysis with CTC HER2-ultralow and ER co-expression, as well as single-cell chromosomal instability

Abstract Background: Metastatic breast cancer (MBC) subtype characterization is critical for effective treatment. The DefineMBC™ multiomic blood biopsy clinical diagnostic combines ctDNA and circulating tumor cell (CTC) analyses to characterize MBC patients when a tissue biopsy is not feasible. Innovation in the DefineMBC 2.0 5-channel immunofluorescent (IF) CTC characterization assay now measures ultralow (UL) levels of HER2 protein expression, ER protein expression, and chromosomal instability (CI) as well as ERBB2 amplification via single- cell sequencing. Cell-level HER2/ER co-detection enables monitoring of receptor conversion during a patient’s MBC treatment journey. As trastuzumab-deruxtecan (T-DxD) has become standard of care for HER2-low disease, distinguishing HER2-UL from HER2[-] by DefineMBC’s liquid biopsy approach may identify additional patients who can benefit from such therapy. This addresses an unmet need given the known shortcomings of tissue biopsy IHC in the metastatic setting as recently noted by communications from NCCN, ASCO, and the College of American Pathologists. Methods: Assay development including analytical validation studies utilized biologically relevant cell lines of epithelial origin and known expression levels of HER2 and ER (MDA-MB-453: HER2[+] & ER[-]; MCF-7: HER2-low & ER[+]; and MCF-7/ERBB2 knockout: HER2[-]) that were spiked into healthy donor blood. Additionally, patients with various forms of MBC were characterized with the new assay. As with all samples, following red blood cell lysis, nucleated cells were deposited on glass slides at high density (∼3E6 WBC/slide). Slides underwent IF staining for cytokeratins (CK), CD31, CD45, HER2, ER, and Hoechst to localize nuclear DNA, followed by scanning and machine learning-based rare cell detection. CK[+], CD31[-]/CD45[-] cells were classified as CTC candidates and assessed for HER2/ER expression. Pathologist-selected CTCs were isolated for single-cell whole genome sequencing and analyzed using a proprietary CTC DNA copy number pipeline to detect CI and amplification at the ERBB2 locus. Results: Analytical validation studies demonstrated the limit of detection at 1 CTC per 12E6 WBC (∼1.6 mL of blood) with a linear range of 1- 300 CTCs per slide. Sensitivity, specificity, accuracy, and precision metrics of the HER2 and ER IF assays were 96%, 96%, 96%, 2% CV; 91%, 95%, 93%, 3% CV; respectively. CTC enumeration precision was validated at greater than 80% for enumeration bins of 0, 1-10, 11-50, and>50 CTCs per sample. During patient testing 7 patients previously called HER2[-] are now designated as consistent with HER2-low by the pathologist, suggesting improved test performance in future clinical validation studies is likely. Conclusions: Advancement of our comprehensive cancer profiling platform now includes ER/HER2-UL/CI co-detection on enumerated CTCs in MBC patients. Clinical studies currently in progress will reveal whether HER2-UL/HER2[+] detection on CTCs will identify patients better suited for T-DxD or trastuzumab, respectively. Citation Format: Raj Srikrishnan, Jordan Ritchie, Alessandra Cunsolo, Andrew Kunihiro, Brandon Guillory, Sara Tin, Zhuo Meng, Ernest T Lam, Bharat Annaldas, Evan Schwab, Nilesh Dharajiya, Timothy Pluard, Martin Blankfard, David Bourdon. Analytical validation of a novel multiomic metastatic breast cancer liquid biopsy test that combines ctDNA analysis with CTC HER2-ultralow and ER co-expression, as well as single-cell chromosomal instability [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A001.

Abstract B013: An mDETECT assay for monitoring treatment response in metastatic breast cancer patients

Abstract Metastatic breast cancer treatment response is currently assessed every 3-6 months and this long delay results in many patients undergoing ineffective and toxic treatments for long periods of time. We have developed the methylation DETEction of Circulating Tumour DNA (mDETECT) assay, a targeted DNA methylation-based Next Generation Sequencing liquid biopsy that detects cancer-specific patterns in all subtypes of breast cancer. The assay targets 60 differentially hypermethylated regions in breast cancer across the genome and assesses over 400 individual CpGs with an average of 8 CpGs per target amplicon. The assay has been assessed on DNA from 73 breast cancer tumour samples which on average had 40 regions hypermethylated per patient with similar rates across all subtypes. We will present results from plasma samples from locally advanced and metastatic breast cancer patients along with plasma from age-matched, healthy female controls. A prospective, multi-centre observational cohort study to monitor metastatic breast cancer patients using the mDETECT liquid biopsy as they undergo treatment is active and recruiting patients. Blood is drawn with every standard-of-care blood draw for up to 3 years. Plasma has been assessed using the mDETECT assay to determine the methylation status of the DNA at each time point. 35 patients have been enrolled to date with ongoing recruitment up to 150 patients. Patients are being monitored with the mDETECT assay for earlier detection of disease progression on a treatment. They will also be monitored through treatment changes to assess a patient’s initial response to a given treatment. Changes in mDETECT levels will be correlated with clinical response to determine if the mDETECT breast cancer assay can detect a response to treatment at an earlier timepoint. This assay could allow for improved monitoring of treatment response allowing clinicians to make informed decisions, improving outcomes and prolonging patient’s lives. Citation Format: Keira Frosst, Brooke Wilson, Katrina Cristall, Catherine Crawford-Brown, Christopher R Mueller. An mDETECT assay for monitoring treatment response in metastatic breast cancer patients [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B013.

Cost-Effectiveness of Trastuzumab Deruxtecan in Patients with Unresectable or Metastatic HER2-Low Breast Cancer Who Have Received Prior Chemotherapy.

In 2021, breast cancer affected 75,619 women in Denmark. Approximately 50% of breast cancers are considered human epidermal growth factor receptor2 (HER2)-low. The DESTINY-Breast04 (DB-04) trial led to European Medicines Agency (EMA) approval of trastuzumab deruxtecan (T-DXd) as a treatment for patients with unresectable or metastatic HER2-low breast cancer who have received prior chemotherapy in the metastatic setting or developed disease recurrence during or within 6months of completing adjuvant chemotherapy. Moreover, the Danish Breast Cancer Group guidelines recently included T-DXd as a treatment for HER2-low metastatic breast cancer. This economic evaluation aims to estimate the cost-effectiveness of T-DXd for the approved EMA indication in Denmark. A three-state-progression-free, post-progression, and death-partitioned survival model was developed to estimate the cost-effectiveness of T-DXd versus treatment of physician's choice over a lifetime horizon following the Danish Medicines Council guidelines. Clinical data were gathered from the DB-04 trial, and cost and resource use data were sourced from the literature. Sensitivity and scenario analysis were conducted to explore uncertainty. T-DXd led to 0.78 incremental quality-adjusted life years (QALYs) gained and incurred DKK621,325 in incremental costs compared to the treatment of physician's choice. This resulted in an incremental cost-effectiveness ratio of DKK795,181 per QALY gained, which falls below the willingness-to-pay threshold. Sensitivity and scenario analyses showed the robustness of the deterministic result, with T-DXd remaining cost-effective. Our study demonstrates that T-DXd is a cost-effective treatment for patients with HER2-low unresectable or metastatic breast cancer who have received prior chemotherapy in Denmark.

Value-Based Healthcare in Practice: IDEATE, a Collaboration to Design and Test an Outcomes-Based Agreement for a Medicine in Wales.

To develop a sustainable, scalable methodology for the design of outcome-based agreements (OBAs) that works on the ground and dynamically overcomes historical challenges. Project IDEATE co-created solutions to known (and emergent) challenges via iterative workshops and real-world data analysis to develop and refine a hypothetical model for an OBA in a trusted research environment. A cross-disciplinary collaboration between National Health Service (NHS) Wales, industry and academia was developed. Data were collected from Welsh national datasets and used to construct a novel linked dataset. OBA scenarios, with different contract parameters, were analysed to assess impact on the proportion of contract payment due and the volatility of payments. An approved, in market, locally advanced and metastatic breast cancer treatment was selected as the test case. The total number of patients in the treatment cohort (2017-2020) was n = 99, and 286 in the control cohort (2014-2016). The final outcome variables selected were: (1) 1-year survival,( 2) intolerance to treatment (deferral), and (3) the total days disrupted by care. The primary scenario included all three outcomes measured at the population level and used a linear payment model. Volatility analyses demonstrated contract parameters can dramatically alter the contract output with greatest risk from a single, binary outcome contract design. The design of an OBA is a complex process that requires a multi-disciplinary approach. By assessing solutions to data, outcomes and contracting challenges, IDEATE provides a strong foundation for future success of OBAs in the UK. Outcome-based agreements (OBAs) are a way to pay for medicines if they help patienthealth in a specific way over time. These agreements can make it faster for people to get new medicines, but they also have challenges, like needing a lot of time and effort to manage them. A team from the NHS Wales, life sciences, and Swansea University created Project IDEATE to find a better way to design OBAs and solve some of these problems. Welsh datasets were used to create a new breast cancer dataset to test different OBAs and see how payments would change. A breast cancer treatment was used for the project. The project had 99 patients who got the medicine (2017-2020) and 286 patients who had breast cancer but did not get the medicine (2014-2016). Three health outcomes were measured: (1) living for one year after treatment, (2) patients needing to stop the medicine, and (3) days spent in care. The main OBA option we tested used all three health outcomes; the more the outcomes improved, the more the payments could go up until they hit the highest amount agreed. The analysis showed that the way an OBA is designed can make a big difference in how stable or risky it is, especially if one ofthe health outcomes has only two options. Project IDEATE showed that making an OBA can be hard, but when people from different fields work together, they can overcome many challenges and succeed.

Efficacy and safety of sacituzumab govitecan Trop-2-targeted antibody-drug conjugate in solid tumors and UGT1A1*28 polymorphism: a systematic review and meta-analysis.

Sacituzumab govitecan (SG) is a promising Trop-2-targeted antibody-drug conjugate (ADC) approved for the treatment of metastatic triple-negative breast cancer (TNBC). Early phase clinical trials have demonstrated good clinical activity and safety profile of SG in various tumor types, albeit with differing response rates and durations. The aim of this systematic review and meta-analysis was to evaluate the clinical efficacy and toxicity of SG and the influence of UGT1A1*28 genotype in clinical trials involving solid tumors. A systematic review of the literature from publicly available databases was performed on February 15, 2024 whereby studies published till 15 February 2024 were retrieved according to PRISMA guidelines [PROSPERO #CRD42022359943]. Data extracted included tumor type, sample size, demographic information, SG dose, UGT1A1*28 status, toxicity events, duration of follow-up, response, and survival outcomes. Risks of bias analysis was refereed using the Joanna Briggs Institute quality assessment tool for the cohort and RCT studies using 11 and 13 parameters, respectively. Statistical analysis was performed using the DerSimonian and Laird inverse variance methods. Heterogeneity was assessed using the I2 statistic and Χ2 tests. P value < 0.05 was considered as statistical significance. Eleven eligible clinical trials comprised of 1578 patients harboring various tumor types including TNBC, lung, genitourinary and gastrointestinal malignancies were included in the systematic review and meta-analysis. Pooled incidences of severe adverse events were minimal at <10%, with the exception of grade 3-4 neutropenia at 37.4%. The median PFS and OS across all studies were 4.9 (95%CI: 4.0-5.8) months and 9.6 (95%CI: 7.6-11.6) months, respectively. Objective response rate across all studies evaluated was 17.1% (95%CI: 12.0-22.1). Our systematic review and meta-analysis confirmed that SG confers good clinical activity in certain solid tumor types and was tolerable with minimal adverse events. The potential utility of UGT1A1*28 genotyping in predicting clinical response and outcomes could not be determined due to the limited number of studies with available UGT1A1 genotype data.

Cost minimization analysis of treatments for metastatic HER2-positive breast cancer in Peru: Fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injections.

The main objective of this study is to determine whether the employment of fixed-dose combination of pertuzumab and trastuzumab for subcutaneous injection (PH FDC SC; and Phesgo as brand name) to treat metastatic HER2-positive breast cancer patients would minimize costs compared to the traditional treatment of separate intravenous doses of pertuzumab and trastuzumab in Peru. To achieve this, we used EsSalud (the social security health insurance) data and assessed it through a mixed strategy, which consisted of a quantitative and a qualitative approach. The first one aimed to calculate the direct (non-drug consumables, drugs, and healthcare professionals) and indirect costs of both treatments to develop a comparison, whilst the second aimed to validate information and internalize the procedure in an EsSalud context. Overall, we found that the usage of PH FDC SC would be cost saving in EsSalud's context. Specifically, we found three main advantages. Firstly, PH FDC SC generates a savings of 62% in non-drug consumables, which helps alleviate the healthcare system budget constraint. Secondly, its adoption frees up 61 hours of treatment and observation time for a single patient per year, which in turn increases the attention capacity of the healthcare system in terms of nursing hours and chemotherapy couches. Thirdly, the reduction of clinic time supposes an advantage for the patient in the form of increased productivity and well-being. Hence, the adoption of this drug would improve the quality of life of patients while reducing costs and pressure on the healthcare system. This is aligned with the strategy of prioritizing the appropriate breast cancer treatment within the National Cancer Care Plan. In this regard, we also found that the savings produced from switching from the traditional intravenous treatment to the subcutaneous one would allow EsSalud to afford full annual costs of 2 additional treatments, but without increasing their budget. This would cover 7% of the gap of 29 patients who do not have access to full treatment.

Updates in Treatment of HER2-positive Metastatic Breast Cancer.

The therapeutic landscape for HER2-positive metastatic breast cancer has exploded in the last two decades following the initial advent of trastuzumab, a monoclonal antibody. While the first line treatment has remained a combination of dual HER2 blockade with taxane chemotherapy, we now have several exciting options in the second line and beyond. The introduction of antibody-drug conjugates, in specific trastuzumab deruxtecan, has resulted in the best progression-free survival among patients with this subtype of breast cancer. Given the excellent outcomes of these drugs, clinical trials are now evaluating the role of ADCs in the front-line setting in previously untreated patients. In addition, there are also clinical trials evaluating the role of other targets in patients with HER2-positive cancers, including PI3KCA mutations, PD-L1 and CDK4/6. Given the predilection for brain metastases in this population, there is enthusiasm to identify the optimal combination of effective treatments. Tucatinib, capecitabine, and trastuzumab combination represent one such promising strategy. With the increasing longevity of these patients, important clinical questions include optimal treatment sequencing, the role of de-escalation of treatment in excellent responders, and the associated financial toxicity. Despite the aggressive nature of this subtype of breast cancer, the outcomes continue to improve for these patients with the evolving treatments.

A nanoencapsulated oral formulation of fenretinide promotes local and metastatic breast cancer dormancy in HER2/neu transgenic mice

BackgroundPrevention and treatment of metastatic breast cancer (BC) is an unmet clinical need. The retinoic acid derivative fenretinide (FeR) was previously evaluated in Phase I-III clinical trials but, despite its excellent tolerability and antitumor activity in preclinical models, showed limited therapeutic efficacy due to poor bioavailability. We recently generated a new micellar formulation of FeR, Bionanofenretinide (Bio-nFeR) showing enhanced bioavailability, low toxicity, and strong antitumor efficacy on human lung cancer, colorectal cancer, and melanoma xenografts. In the present study, we tested the effect of Bio-nFeR on a preclinical model of metastatic BC.MethodsWe used BC cell lines for in vitro analyses of cell viability, cell cycle and migratory capacity. For in vivo studies, we used HER2/neu transgenic mice (neuT) as a model of spontaneously metastatic BC. Mice were treated orally with Bio-nFeR and at sacrifice primary and metastatic breast tumors were analyzed by histology and immunohistochemistry. Molecular pathways activated in primary tumors were analyzed by immunoblotting. Stem cell content was assessed by flow cytometry, immunoblotting and functional assays such as colony formation ex vivo and second transplantation assay in immunocompromised mice.ResultsBio-nFeR inhibited the proliferation and migration of neuT BC cells in vitro and showed significant efficacy against BC onset in neuT mice. Importantly, Bio-nFeR showed the highest effectiveness against metastatic progression, counteracting both metastasis initiation and expansion. The main mechanism of Bio-nFeR action consists of promoting tumor dormancy through a combined induction of antiproliferative signals and inhibition of the mTOR pathway.ConclusionThe high effectiveness of Bio-nFeR in the neuT model of mammary carcinogenesis, coupled with its low toxicity, indicates this formulation as a potential candidate for the treatment of metastatic BC and for the adjuvant therapy of BC patients at high risk of developing metastasis.

CDK4/6 inhibition initiates cell cycle arrest by nuclear translocation of RB and induces a multistep molecular response

CDK4/6 inhibitors are standard of care in the treatment of metastatic breast cancer. Treatment regimen consists of a combination with endocrine therapy, since their therapeutic efficacy as monotherapy in most clinical trials was rather limited. Thus, understanding the molecular mechanisms that underlie response to therapy might allow for the development of an improved therapy design. We analyzed the response to the CDK4/6 inhibitor palbociclib in bladder cancer cells over a 48-hour time course using RNA sequencing and identified a multi-step mechanism of response. We next translated these results to the molecular mechanism in bladder cancer cells upon PD treatment. The initial step is characterized by translocation of the RB protein into the nucleus by activation of importin α/β, a mechanism that requires the NLS sequence. In parallel, RB is proteolyzed in the cytoplasm, a process regulated by gankyrin and the SCF complex. Only hypophosphorylated RB accumulates in the nucleus, which is an essential step for an efficient therapy response by initiating G1 arrest. This might explain the poor response in RB negative or mutated patients. At later stages during therapy, increased expression of the MiT/TFE protein family leads to lysosomal biogenesis which is essential to maintain this response. Lastly, cancer cells either undergo senescence and apoptosis or develop mechanisms of resistance following CDK4/6 inhibition.

Real‑world evaluation of the efficacy of immune checkpoint inhibitors in the treatment of metastatic breast cancer.

The present study aimed to assess the efficacy and safety of immune checkpoint inhibitor (ICI)-based therapy in patients with metastatic breast cancer (MBC). Therefore, eligible patients with histologically confirmed MBC, treated with ICI-based therapy, were enrolled. The primary endpoint was progression-free survival (PFS) and the secondary endpoints included objective response rate (ORR), disease control rate (DCR), overall survival (OS) and safety. A total of 90 patients with MBC, treated with ICI-based therapy, with different treatment lines, were included in the present study. The median age was 50 years (range, 27-76). The predominant tumor subtypes were triple negative (53.3%) and luminal (31.1%) breast cancer. The majority of patients (61.1%) were heavily pretreated (lines of treatment, ≥3). Approximately half of the patients (46.7%) had ≥3 metastatic sites. The overall ORR was 36.7% (33/90 patients), while a DCR of 78.9% (71/90 patients) was also recorded. With a median follow-up of 16.0 months, the median PFS and OS were 4.9 months [95% confidence interval (CI), 3.8-6.1] and 13.9 months (95% CI, 9.5-18.2), respectively. Patients treated with ICIs as first-line therapy exhibited notable improvement, with a median PFS of 11.0 months (95% CI, 6.0-16.0) and a median OS of 24.3 months (95% CI, 11.4-37.2). In addition, the pretreatment blood platelet-to-lymphocyte ratio was an independent risk factor for PFS [hazard ratio (HR)=2.406; 95% CI, 1.325-4.370; P=0.004] and OS (HR=2.376; 95% CI, 1.059-5.328; P=0.036). The most common adverse events were nausea (44.4%), neutropenia (42.0%) and alanine aminotransferase/aspartate aminotransferase elevation (22.2%). Furthermore, three (3.3%) patients developed grade 1/2 immuno-related toxicity and recovered after supportive care. Overall, the present study suggested that the ICI-based therapy exhibited encouraging clinical outcomes with manageable toxicity in patients with MBC in real-world settings, with the most favorable efficacy in first-line treatment.

SUMOylation regulates the aggressiveness of breast cancer-associated fibroblasts.

Cancer-associated fibroblasts (CAFs) are the most abundant stromal cellular component in the tumor microenvironment (TME). CAFs contribute to tumorigenesis and have been proposed as targets for anticancer therapies. Similarly, dysregulation of SUMO machinery components can disrupt the balance of SUMOylation, contributing to tumorigenesis and drug resistance in various cancers, including breast cancer. We explored the role of SUMOylation in breast CAFs and evaluated its potential as a therapeutic strategy in breast cancer. We used pharmacological and genetic approaches to analyse the functional crosstalk between breast tumor cells and CAFs. We treated breast CAFs with the SUMO1 inhibitor ginkgolic acid (GA) at two different concentrations and conditioned media was used to analyse the proliferation, migration, and invasion of breast cancer cells from different molecular subtypes. Additionally, we performed quantitative proteomics (SILAC) to study the differential signalling pathways expressed in CAFs treated with low or high concentrations of GA. We confirmed these results both in vitro and in vivo. Moreover, we used samples from metastatic breast cancer patients to evaluate the use of GA as a therapeutic strategy. Inhibition of SUMOylation with ginkgolic acid (GA) induces death in breast cancer cells but does not affect the viability of CAFs, indicating that CAFs are resistant to this therapy. While CAF viability is unaffected, CAF-conditioned media (CM) is altered by GA, impacting tumor cell behaviour in different ways depending on the overall degree to which SUMO1-SUMOylated proteins are dysregulated. Breast cancer cell lines exhibited a concentration-dependent response to conditioned media (CM) from CAFs. At a low concentration of GA (10µM), there was an increase in proliferation, migration and invasion of breast cancer cells. However, at a higher concentration of GA (30µM), these processes were inhibited. Similarly, analysis of tumor development revealed that at 10µM of GA, the tumors were heavier and there was a greater degree of metastasis compared to the tumors treated with the higher concentration of GA (30µM). Moreover, some of these effects could be explained by an alteration in the activity of the GTPase Rac1 and the activation of the AKT signalling pathway. The results obtained using SILAC suggest that different concentrations of GA affected cellular processes differentially, possibly influencing the secretome of CAFs. Treatment of metastatic breast cancer with GA demonstrated the use of SUMOylation inhibition as an alternative therapeutic strategy. The study highlights the importance of SUMOylation in the tumor microenvironment, specifically in cancer-associated fibroblasts (CAFs). Targeting SUMOylation in CAFs affects their signalling pathways and secretome in a concentration-dependent manner, regulating the protumorigenic properties of CAFs.

An Overview of Receptor-targeted Nanotechnological Approaches for the Treatment of Metastatic Breast Cancer

Abstract: Breast cancer (BC) is the second most prevalent cancer among women and can originate from the tubes, connective tissue, and lobules of the breast. The primary focus of this review is to highlight the significant advancement in the development of receptor-targeted nanotherapy for the management of metastatic breast cancer. These innovative systems directly target the specific cancer cell receptor to enhance the precision and effectiveness of the treatment. Inadequate therapy and incorrect diagnosis in conventional treatment have contributed to the rising mortality rate from breast cancer. BC that has spread to another organ in the body, commonly called Metastatic breast cancer (MBC) or Stage IV metastases, is an aggressive and heterogeneous illness that decreases the prognosis. The current treatment methods for MBC are similar to initial-stage breast cancer, which involve hormonal surgery, chemotherapy, immunotherapy, and radiation therapy with poor specificity and invasive. Moreover, treating MBC is more difficult because the cancer cells varies depending on the organ. Nanotechnology provides valuable insights for treating MBC that enable the early identification of tumor cells. Moreover, it can also transport therapeutic agents directly to the targeted sites while reducing the toxicity to healthy tissue. Due to its multifunctional, programmable, and trackable properties, future research and treatment may succeed with nanotechnology-based imaging and therapy. The present study summarizes an overview of nanotechnology-based drug delivery methods (NDDM) and receptor-targeting nanotherapy (RTN) that are applied in MBC therapy to gain attention in clinical applications. Clinical trial studies have also been discussed along with receptor-targeting nanomedicine and the status of the most relevant patent.

Disparities in receipt of 1-st line CDK4/6 inhibitors with endocrine therapy for treatment of hormone receptor positive, HER2 negative metastatic breast cancer in the real-world setting

ObjectiveThis study used real-world observational data to compare profiles of patients receiving different first-line treatment for hormone receptor positive (ER+), HER2 negative, metastatic breast cancer (MBC): CDK4/6 inhibitors (CDK4/6i) in combination with endocrine therapy (ET) versus ET alone.MethodFrom a nationwide electronic health record-derived Flatiron Health de-identified database including 280 US cancer clinics, we identified patients with hormone receptor positive, HER2 negative, metastatic breast cancer receiving 1st -line therapy with ET alone or CDK4/6i plus ET between February 2015 and November 2021. Patient sociodemographic status, MBC treatment regimen and outcomes were the focus of this analysis. Patient characteristics were compared using t-tests and chi-square tests. Logistic regression analysis was performed to examine the association of patient characteristics with the likelihood of receiving 1st -line CDK4/6i plus ET vs. ET alone. Kaplan-Meier method and Cox proportional hazards were used to test the impact of 1st -line treatment regimen on real-world progression-free survival (PFS) and overall survival (OS). Baseline characteristics were balanced using inverse probability weighting (IPW).ResultsThe study population included 3,917 patients receiving CDK4/6i plus ET (n = 2170) and ET alone (n = 1747) for their MBC. Compared to patients receiving ET alone, those receiving CDK4/6i plus ET were younger (mean age 66.8 vs. 68.6, p < 0.001), more likely to present with de novo MBC (p < 0.001), had better performance status (50.2% vs. 40.5% patients with ECOG value 0, p = 0.001) and lower number of comorbidities (29.7% vs. 26.6% ≥ 1 comorbidity, p < 0.001). Logistic regression revealed increased odds of CDK4/6i plus ET in individuals aged 50–64 (OR: 3.42, 95% CI [2.41, 4.86]) and 65–74 (OR: 3.18, 95% CI [1.68, 6.02]) versus those aged 18–49 years of age. Black individuals had lower odds of CDK4/6i plus ET (OR: 0.76, 95% CI [0.58, 1.00]) compared to White individuals. Other characteristics associated with lower odds of CDK4/6i plus ET included patients with stage III disease (OR: 0.69, 95% CI [0.52, 0.92]), lower performance status (OR: 0.50, 95% CI [0.40, 0.62]), and Medicare insurance (OR: 0.73, 95% CI [0.30, 1.78]) compared to those with commercial and Medicaid insurance. After IPW adjustment, use of CDK4/6i plus ET as 1st -line treatment was associated with significantly longer median PFS compared to ET alone (27 vs. 17 months; hazard ratio [HR] = 0.61, p < 0.001). Median OS was 52 months in the CDK4/6i plus ET group and was 42 months with ET alone (HR = 0.74, p < 0.001).ConclusionIn this real-world database, disparities in receiving 1st -line CDK4/6 inhibitors were seen by age, diagnosis stage, baseline performance status, comorbidity, and insurance status. In adjusted analysis, the use of 1st -line CDK4/6i plus ET yielded better PFS and OS rates than ET alone. Further efforts are essential to enhance equitable use of and access to this crucial drug class.

Adaptive enrichment trial designs using joint modelling of longitudinal and time-to-event data.

Adaptive enrichment allows for pre-defined patient subgroups of interest to be investigated throughout the course of a clinical trial. These designs have gained attention in recent years because of their potential to shorten the trial's duration and identify effective therapies tailored to specific patient groups. We describe enrichment trials which consider long-term time-to-event outcomes but also incorporate additional short-term information from routinely collected longitudinal biomarkers. These methods are suitable for use in the setting where the trajectory of the biomarker may differ between subgroups and it is believed that the long-term endpoint is influenced by treatment, subgroup and biomarker. Methods are most promising when the majority of patients have biomarker measurements for at least two time points. We implement joint modelling of longitudinal and time-to-event data to define subgroup selection and stopping criteria and we show that the familywise error rate is protected in the strong sense. To assess the results, we perform a simulation study and find that, compared to the study where longitudinal biomarker observations are ignored, incorporating biomarker information leads to increases in power and the (sub)population which truly benefits from the experimental treatment being enriched with higher probability at the interim analysis. The investigations are motivated by a trial for the treatment of metastatic breast cancer and the parameter values for the simulation study are informed using real-world data where repeated circulating tumour DNA measurements and HER2 statuses are available for each patient and are used as our longitudinal data and subgroup identifiers, respectively.

Autophagy activator-loaded bicomponent peptide nanocarriers for phototherapy-triggered immunity enhancement against metastatic breast cancer

Mild autophagy accompanied with immunogenic cell death (ICD) effect destructs immune-associated antigens, weakening the immune response against tumor growth. To address this dilemma, we develop a peptide-based bicomponent nanocarrier with encapsulation of a cellular hyperautophagy activator (STF-62247) for near-infrared (NIR) photo/immunotherapy to eliminate primary and metastatic breast tumors. The electrostatic-driven nanodrug (PPNPs@STF) with active-targeting and efficient endosomal escape can induce specific ICD effect upon NIR laser irradiation, and trigger autophagy to a mild activation state. Notably, the simultaneously released STF-62247 precisely promotes autophagy to an overactivated state, resulting in autophagic death of tumor cells and further boosting ICD-related antigen presentation. More importantly, the combined photo/immunotherapy of PPNPs@STF not only inhibits tumor cell proliferation, but also promotes dendritic cells (DCs)-associated immune response. In 4 T1 tumor-bearing mice, PPNPs@STF effectively inhibits growth of primary and distant tumors, and suppresses lung metastasis with a minimized side effect. This study provides a hyperautophagy activator-assisted strategy that can enhance ICD-based antitumor immune response for the treatment of metastatic breast cancer.

Real-World Clinical Outcomes of Treatment With Olaparib for BRCA1/2 Mutation-Positive Metastatic Breast Cancer in Japanese Patients.

Background Olaparib is effective in the treatment of metastatic breast cancer (MBC) patients, mainly confirmed by deleterious germline BRCA mutations. However, real-world data are scarce. Methodology A total of 10 cases from our institute and 17 cases from the relevant Japanese literature were reviewed. All 27 patients had MBC with confirmed deleterious germline BRCA mutations. Tumor reduction, response duration, disease-free interval (DFI), overall survival (OS), and safety were assessed. Additionally, exploratory research was conducted on the characteristics of a subgroup of patients who had a long-term response to olaparib. Results In the 10 cases from two Juntendo hospitals who received olaparib from July 2018 to December 2021, the median age was 48 years (range = 37-63 years). The same numbers of BRCA1 and BRCA2 mutations and the same ratios of luminal and triple negative (TN) breast cancer cases were observed. The metastatic sites, mainly visceral, included the lungs (n = 4), liver (n = 5), and bone (n = 6). The median duration of drug use was four months (range = 1-36 months). The median number of treatment regimens from metastasis to olaparib administration was 2.0 (range = 1-9 regimens). The median DFI was 21 months (range = 0-106 months). The median OS was not reached (range = 16-191 months). In the subgroup analysis of six cases in which olaparib was effective for four months or more, there was a case where DFI was longer than 100 months. Treatment-related toxicities (TRTs) included neutropenia (n = 5; 50%), anemia (n = 4; 40%), thrombocytopenia (n = 2; 20%), nausea (n = 1; 10%), and fatigue (n = 1; 10%). CTCAE (version 5.0) grade ≥3 TRTs included anemia (n = 1; 10%) and neutropenia (n = 5; 50%). On the other hand, neutropenia was previously said to be as low as 27.3%, lower than anemia (40.0%), in a population including various races. We additionally examined another 17 cases from the Japanese literature. Conclusions To our knowledge, this study reports the first real-world data of Japanese patients with MBC and confirmed deleterious germline BRCA mutations. Our data showed that olaparib is effective in the real world. The incidence of neutropenia seemed higher in Japanese patients.

Advances in Immunotherapy for the Treatment of Metastatic Breast Cancer: A Comprehensive Review

Advances in Immunotherapy for the Treatment of Metastatic Breast Cancer: A Comprehensive Review

A 14-year retrospective of HER2 + metastatic breast cancer treatment at one comprehensive cancer center: Impact of the trastuzumab/pertuzumab and trastuzumab-emtansine sequence versus trastuzumab on overall survival.

Introduction: Monoclonal antibodies represent a significant improvement in the treatment of the HER2 + metastatic cancer, which is associated with a worse prognosis. The objective of this study was to compare overall survival (OS) data in patients treated with trastuzumab + pertuzumab followed by trastuzumab-emtansine (T-DM1) in the second line of metastatic treatment (Arm A) versus patients treated with trastuzumab alone (Arm B). Progression-free survival (PFS) in first-line metastatic patients was also compared in both arms. Methods: This single-center retrospective study included patients from February 2008 to August 2022. OS and PFS of both arms were described and estimated using the Kaplan-Meier method. Data were extracted from electronic medical records and CHIMIO prescribing software. Results: The total duration of metastatic treatment of the 82 patients was significantly longer in the arm A (43.2 ± 28 months vs 33.6 ± 28.9 months), as was the median time to death (59 vs 52 months). The OS data showed a significant reduction in the risk of death in the arm A (Hazard Ratio = 0.59; 95% Confidence Interval [0.37-0.94]; p = 0.02). No difference was shown for PFS. Conclusion: The trastuzumab/pertuzumab/T-DM1 combination showed a significant improvement in OS. Our results are in line with the CLEOPATRA and EMILIA studies, but long-term responders in the arm A may have impacted our results. The absence of difference in term of PFS in first metastatic line may be explained by a selection bias, as patients in the arm A potentially have more aggressive forms.

Antibody-Drug Conjugates in the Treatment of Metastatic Breast Cancer: The Emerging Questions of Sequence and Resistance

Antibody-Drug Conjugates in the Treatment of Metastatic Breast Cancer: The Emerging Questions of Sequence and Resistance

8595 Brain Penetration Impedes SERD Efficacy in Breast Cancer Pre-clinical Models

Abstract Disclosure: S.E. Wardell: None. B. Chakraborty: None. S. Artham: None. M.A. Newlin: None. M. Kirkland: None. C. Chang: None. D.P. McDonnell: None. Most breast cancers express the estrogen receptor (ER, ESR1), and agents that target ER remain the cornerstone of interventions used to treat this disease at all stages. Aromatase inhibitors (AI), which block estrogen synthesis, and the selective ER downregulator (SERD) fulvestrant were developed with the goal of achieving absolute inhibition of ER signaling in tumors. However, it has been assumed that the clinical efficacy (and utility) of fulvestrant is somewhat limited by its poor pharmaceutical properties and the requirement that it be administered by intramuscular injection. This, together with the observation that the activating ESR1 mutations selected for during AI treatment are not effectively inhibited by fulvestrant, encouraged the development of new classes of SERDs that achieve sufficient exposure to saturate and degrade ER in tumors. The recent approval of the second-generation SERD elacestrant for the treatment of breast cancers harboring ESR1 mutations was a major advance in approaches to target ER in advanced breast cancer. Several additional oral SERDs have been developed and evaluated as potential treatments for advanced metastatic breast cancer. Despite showing substantial efficacy in pre-clinical assays that assess ER downregulation and gene transcription, and notably equivalent antitumor activities in cell line derived and PDX tumors in immunocompromised mice, the clinical development of the majority of these SERDs has been discontinued for lack of efficacy. In reviewing the available clinical data across many SERD programs, we noted that some drugs demonstrated a paradoxical, non-linear response curve with higher doses exhibiting less efficacy than lower doses. Probing this pharmacology in animal models we determined that the ability of SERDs to cross the blood brain barrier and attenuate ER signaling in the hypothalamus was a key differentiator of SERDs. In validated syngeneic models of breast cancer, we observed doses of fulvestrant having confirmed brain exposure stimulated tumor growth independent of tumor ER-status. We evaluated the ability of several next generation SERDs for their brain penetrance and demonstrated that SERD presence in the brain was associated with a stimulatory effect on tumor growth. Interestingly, administration of a low dose of 17b-estradiol (E2) together with a brain excluded SERD further repressed tumor growth, highlighting a potentially beneficial anti-tumor role for estrogen signaling in the brain. Furthermore, combination of a brain excluded SERM with E2 also resulted in increased tumor growth repression; thus, ER downregulation is dispensable for the cooperative activity observed for estrogens administered together with a peripheral ER antagonist. These data suggest that differences in tissue pharmacology, as opposed to differences in ability to degrade ER, is likely to be a major differentiator of ER modulators. Presentation: 6/3/2024