Progressive Brain Metastases Research Articles

Connexins orchestrate progression of breast cancer metastasis to the brain by promoting FAK activation.

Brain metastasis is a complication of increasing incidence in patients with breast cancer at advanced disease stage. It is a severe condition characterized by a rapid decline in quality of life and poor prognosis. There is a critical clinical need to develop effective therapies to prevent and treat brain metastases. Here, we describe a unique and robust spontaneous preclinical model of breast cancer metastasis to the brain (4T1-BM2) in mice that has been instrumental in uncovering molecular mechanisms guiding metastatic dissemination and colonization of the brain. Key experimental findings were validated in the additional murine D2A1-BM2 model and in human MDA231-BrM2 model. Gene expression analyses and functional studies, coupled with clinical transcriptomic and histopathological investigations, identified connexins (Cxs) and focal adhesion kinase (FAK) as master molecules orchestrating breast cancer colonization of the brain. Cx31 promoted homotypic tumor cell adhesion, heterotypic tumor-astrocyte interaction, and FAK phosphorylation. FAK signaling prompted NF-κB activation inducing Lamc2 expression and laminin 332 (laminin 5) deposition, α6 integrin-mediated adhesion, and sustained survival and growth within brain parenchyma. In the MDA231-BrM2 model, the human homologous molecules CX43, LAMA4, and α3 integrin were involved. Systemic treatment with FAK inhibitors reduced brain metastasis progression. In conclusion, we report a spontaneous model of breast cancer metastasis to the brain and identified Cx-mediated FAK-NF-κB signaling as a mechanism promoting cell-autonomous and microenvironmentally controlled cell survival for brain colonization. Considering the limited therapeutic options for brain metastatic disease in cancer patients, we propose FAK as a therapeutic candidate to further pursue in the clinic.

Implementing Modernized Eligibility Criteria in US National Cancer Institute Clinical Trials.

In 2018, the Cancer Therapy Evaluation Program (CTEP) at the US National Cancer Institute published new protocol template language that focused on organ function and prior and concurrent cancers in an effort to modernize eligibility criteria for cancer treatment trials. We conducted an analysis of CTEP-supported trials to evaluate the uptake and incorporation of the new language. The analysis included evaluation of 122 protocols approved in the years 2018-2020 for inclusion of the modernized eligibility criteria and consistency with new protocol template language related to 7 major eligibility criteria. These were cardiac function, liver function, kidney function, HIV status, prior and/or concurrent malignancies, treated and/or stable brain metastasis, and new and/or progressive brain metastases. Overall, CTEP trials evaluated in this period demonstrated that eligibility criteria were implemented to a relatively high degree ranging from a low of 54.1% for prior and/or concurrent malignancies to a high of 93.4% for eligibility criteria related to HIV infection. The findings demonstrate that modernized eligibility criteria can be successfully implemented but that consistent implementation requires sustained focused effort. As a result of these findings, CTEP began a new initiative in January 2022 that incorporates a specific review of eligibility criteria for new protocols to promote and improve consistency with the modernization effort.

281MO Quality of life and neurocognitive function in patients with active brain metastases of HER2-positive breast cancer treated with trastuzumab-deruxtecan: Secondary endpoint analysis of the prospective single-arm phase II TUXEDO-1 trial

Maintaining quality-of-life (QoL) and neurocognitive function is a main goal in the setting of brain metastases (BM) in HER2-positive breast cancer (BC) patients (pts). TUXEDO-1 investigated QoL and neurocognitive function during trastuzumab-deruxtecan (T-DXd) therapy in HER2-positive BC BM pts. TUXEDO-1 is a prospective, open-label, single-arm phase II trial and enrolled adult HER2-positive BC pts with newly diagnosed BM or progressive BM with no immediate need for local therapy. T-DXd was administered every three weeks at standard dose until disease progression, unacceptable side-effects or consent withdrawal. A secondary endpoint of the trial was QoL and pts completed the EORTC QLQ-C30 questionnaire at cycle 1, 3, 5 and every 9 weeks thereafter. A final assessment was performed at first survival follow-up three months after end-of-treatment. Linear mixed-effect models were used to analyze changes in QoL scores (sub-domains global QoL score, cognitive/emotional/physical function scores; scores range from 0-100) over time (slope). TUXEDO-1 is registered with EU Clinical Trials Register (EudraCT 2020-000981-41) and ClinicalTrials.gov (NCT04752059) and enrollment is closed. Fifteen pts (14 females, 1 male; 12/15 luminal B) were enrolled and received at least one dose of T-DXd. Median age at inclusion was 69 (range 30-76) years. Pts received a median of two (range 1-5) prior systemic therapies for metastatic BC and 9/15 (60%) pts received prior local therapy (whole brain radiotherapy, stereotactic radiotherapy or neurosurgery) for BM. Neurologic symptoms at inclusion were present in 6/15 (40%) of pts. Median follow-up time was 11 months. The QLQ-C30 global QoL (slope -0.13 per follow-up visit, p=0.953), the physical (0.52, p=0.363), emotional (-0.24, p=0.835) as well as the cognitive functioning scores (-0.79, p=0.429) were all maintained over the duration of T-DXd therapy. TUXEDO-1 showed maintained QoL and neurocognitive function during T-DXd therapy in HER2-positive BC BM pts. Our data support first-line systemic therapy with T-DXd in pts with active BM.

Postoperative progression of brain metastasis is associated with seizures.

Seizures in patients with brain metastases have an impact on morbidity and quality of life. The influence of tumor growth on the risk of seizures in these patients is not well defined. In this cohort study, we evaluated adult patients from the University Hospital of Zurich following resection of brain metastases from solid tumors, with or without preoperative seizures, at 3, 6, 9, and 12 months postoperatively. Brain magnetic resonance imaging was assessed for tumor progression using the Response Assessment in Neuro-Oncology criteria. The quarterly risk of unprovoked seizures was modeled with mixed effects logistic regression. We analyzed 444 time frames in 220 patients. Progression of brain metastases was independently associated with seizures during the respective quarterly follow-up period (odds ratio=3.9, 95% confidence interval=1.3-11.3, p= .014). Complete resection of brain metastases was associated with a lower risk of seizures (odds ratio= .2, 95% confidence interval= .04-.7, p= .015). Postoperative progression of brain metastases quadrupled the risk of seizures; therefore, vigorous follow-up may be useful to identify tumor progression and gauge the risk of seizures. The identification of patients at high seizure risk may have implications for treatment decisions and influence aspects of daily life. Breakthrough seizures may indicate brain metastases progression.

SYST-13 PHASE II STUDY OF THE COMBINATION OF LIPOSOMAL IRINOTECAN AND PEMBROLIZUMAB FOR TRIPLE-NEGATIVE BREAST CANCER (TNBC) WITH BRAIN METASTASES (BM)

Abstract BACKGROUND Breast cancer is one of the most common cancers associated with brain metastases (BM). Up to 50% of patients with metastatic triple-negative breast cancer (TNBC) develop BM which portends a poor prognosis, with a median survival of 4.4-7.3 months. There is a lack of effective systemic therapy. Irinotecan is a topoisomerase-1 inhibitor with a response rate of 5-23% in advanced breast cancer. Nal-IRI is an intravenous liposomal formulation of irinotecan, with greater efficacy in tumor growth inhibition and the ability to cross the blood brain barrier (BBB) than irinotecan, resulting in a prolonged survival in preclinical TNBC BM models. Additionally, Nal-IRI has demonstrated promising anti-tumor activity in patients with TNBC- BM in a phase-I trial (NCT01770353). Pembrolizumab is a humanized anti-PD-1 monoclonal antibody which has shown efficacy in TNBC. The purpose of this study is to evaluate whether the combination of Nal-IRI and pembrolizumab can provide a synergic effect to control the CNS disease and prolong survival in TNBC with progressive BM. METHODS This is a phase II, single arm trial with a safety lead-in to evaluate the efficacy of nal-IRI (50-70mg/m2 IV Q2W) in combination with pembrolizumab (400mg IV Q6W). Simon’s 2-stage design is used, with 18 patients in the 1st stage and additional 24 at 2nd stage for a total of 42. The first 6 patients will serve as a safety lead-in. Key eligibilities include: histologically/cytologically confirmed TNBC with new or progressive BM; prior immunotherapy is allowed but not prior nal-IRI/irinotecan; prior sacituzumab-govitecan is permitted if disease stable for ≥16-week while on therapy and ≥24-week washout prior to starting trial; measurable disease; and ≤4 prior lines of therapy in the metastatic setting. The primary endpoint is CNS disease control rate (DCR) at 6 months using RANO-BM criteria. Secondary endpoints include CNS and non-CNS ORR, PFS and OS. (ClinicalTrials.gov: NCT05255666)

BSCI-12 BREAST TO BRAIN METASTASIS IS EXACERBATED WITH CHEMOTHERAPY THROUGH BLOOD-CEREBRAL SPINAL FLUID-BARRIER AND INDUCES ALZHEIMER’S-LIKE PATHOLOGY

Abstract Control of breast to brain metastasis remains an urgent unmet clinical need. While chemotherapies are essential in reducing systemic tumor burden, they have also shown to promote non-brain metastatic invasiveness and drug-driven neurocognitive deficits through formation of neurofibrillary tangles (NFT) independently. Now, in this study we investigated the effect of chemotherapy on brain metastatic progression and promoting tumor-mediated NFT. Results show chemotherapies promote increased brain-barrier permeability and facilitate enhanced tumor infiltration, particularly through the blood-cerebrospinal fluid-barrier (BCSFB). This is attributed to increased expression of matrix metalloproteinase 9 (MMP9) which, in turn, mediates loss of Claudin-6 within the choroid plexus cells of the BCSFB. Importantly, increased MMP9 activity in the choroid epithelium following chemotherapy results in cleavage of Tau released from breast cancer cells. This cleaved Tau forms tumor-derived NFT that further destabilize the BCSFB. Our results underline for the first time the importance of the BCSFB as a vulnerable point of entry for brain-seeking tumor cells post-chemotherapy and indicate that tumor cells themselves contribute to Alzheimer’s-like tauopathy.

BSCI-18 ESTROGEN-DEPLETION DECREASES PROGRESSION OF ER¯ BRAIN METASTASES BY PROMOTING AN ANTI-TUMORAL LOCAL IMMUNE RESPONSE

We have shown that 17-β-Estradiol (E2) promotes brain metastasis (BM) of estrogen receptor negative (ER¯) BC cells by inducing neuroinflammatory ER+ astrocytes in the brain niche to secrete pro-metastatic factors critical for early brain colonization. E2-depletion prevented brain colonization of human xenografts (MDA231BR/NSG) and syngeneic (E0711/C57Bl6, 4T1/Balb-c) ER¯ models. Yet, whether E2-depletion can be used to decrease progression of established BM and how E2-dependent modulation of brain immune response contributes to the pro-metastatic effects of E2 remains unclear. To assess whether E2-depletion could decrease BM progression in a model that mimics standard of care for BM, E0771-GFP-luc cells were injected intracardially in syngeneic ovariectomized (OVX)-female C57Bl6 mice supplemented with E2. Seven days after injection (when micrometastases are established), mice received a single 15Gy dose brain irradiation and were randomized to continue receiving E2, E2 withdrawal (E2WD) or E2WD plus the aromatase-inhibitor letrozole (EWD+LET). Endpoint BM (but not systemic metastases) were significantly decreased in E2WD+Letrozole treated mice as compared to E2-treated mice. This effect was abolished when E0711 cells were injected in severely immunocompromised NSG mice or in the absence of brain irradiation, suggesting EWD+LET decreases BM progression through boosting radiation-induced anti-tumor immunity. Accordingly, there were no differences in BM progression in E2, EWD or E2WD+let treated mice in a xenograft model (F2-7 TNBC cells) in NSG mice, even in the presence of brain irradiation. Brain immune-profiling of brain irradiated E2, EWD and EWD+Let C57BL6 mice carrying E0771 BMs shows that brains of EWD+LET-treated mice had a significantly lower fraction of CD4 T cells and an increase in CD8 T cells, suggesting that EWD+letrozole decrease brain metastatic burden in part through modulation of T cells. These results suggest E2-depletion therapies could be used in combination with brain irradiation to decrease progression of BMs and promote an anti-tumoral immune response.

Breast cancer brain metastasis: Current evidence and future directions.

Breast cancer is the most common cancer in women and the second leading cause of cancer-related deaths after lung cancer. Metastasis of the central nervous system is a terrible event for breast cancer patients, affecting their survival and quality of life. Compared with hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer patients, brain metastases are more likely to affect patients with triple-negative breast cancer and human epidermal growth factor receptor 2-positive breast cancer. The treatment of breast cancer has improved greatly in the last two decades. However, brain metastases from breast cancer remain the leading cause of morbidity and mortality. Patients with breast cancer brain metastasis have been in an inferior position due to the lack of clinical research in this field, and they are often explicitly excluded from almost all clinical trials. The occurrence and progression of brain metastases will result in severe cognitive impairment and adverse physical consequences, so we must have a good understanding of the molecular mechanisms of breast cancer brain metastasis. In this article, we have retrieved the latest literature of molecules and pathways associated with breast cancer brain metastasis, summarized common therapy strategies, and discussed the prospects and clinical implications of targeting the molecules involved.

Efficacy and safety of anti-PD1 monotherapy or in combination with ipilimumab after BRAF/MEK inhibitors in patients with BRAF mutant metastatic melanoma

BackgroundPatients with V600BRAF mutant metastatic melanoma have higher rates of progression-free survival (PFS) and overall survival (OS) with first-line anti-PD1 (PD1]+anti-CTLA-4 (IPI) versus PD1. Whether this is also true after...

Re-irradiation in patients with progressive or recurrent brain metastases from extracranial solid tumors: A novel prognostic index.

Most studies evaluating factors associated with the survival of patients with brain metastases (BM) have focused on patients with newly diagnosed BM. This study aimed to identify prognostic factors associated with survival after brain re-irradiation in order to develop a new prognostic index. This 5-year retrospective study included patients treated with repeat-radiotherapy for recurrent BM at the "Instituto Nacional de Cancerología" of Mexico between 2015 and 2019. Significant variables in the multivariate Cox regression analysis were used to create the brain re-irradiation index (BRI). Survival and group comparisons were performed using the Kaplan-Meier method and the log-rank test. Fifty-seven patients receiving brain re-irradiation were identified. Most patients were women (75.4%) with a mean age at BM diagnosis of 51.4 years. Lung and breast cancer were the most prevalent neoplasms (43.9% each). Independent prognostic factors for shorter survival after re-irradiation were: Age >50 years (hazard ratio [HR]:2.5 [95% confidence interval [CI], 1.1-5.8]; p=0.026), uncontrolled primary tumor (HR:5.5 [95% CI, 2.2-13.5]; p < 0.001), lesion size >20 mm (4.6 [95% CI, 1.7-12.2]; p=0.002), and an interval <12 months between radiation treatments (HR:4.3 [95% CI, 1.7-10.6]; p=0.001). Median survival (MS) after re-irradiation was 14.6months (95% CI, 8.2-20.9).MS of patients stratified according to the BRI score was 17.38, 10.34, and 2.82 months, with significant differences between all groups. The new BRI can be easily implemented for the prognostic classification of cancer patients with progressive or recurrent BM from extracranial solid tumors.

Abstract 5817: Exosomal miR-4466 from nicotine-activated neutrophils promotes tumor cell stemness &amp; metabolism in brain metastasis

Abstract Smoking is associated with lung cancer and has a profound impact on tumor immunity. Nicotine, the addictive and non-carcinogenic smoke component, influences various brain cells and the immune system. However, little is known how long-term use of nicotine affects clinical outcomes in patients with brain metastasis. To address this question, we conducted a retrospective analysis of 810 lung cancer patients with smoking history and assessed brain metastasis. We found that lung cancer patients of current smokers have significantly higher brain metastatic incidence compared to the never-smokers. Immune profiling of the brain metastatic lesions among smokers showed predominant infiltration of neutrophils compared to never-smokers. Notably, mice pre-exposed to nicotine showed a significantly increased number of neutrophils in the brains even before implantation of cancer cells (pre-metastatic niche), and their numbers progressively increased during the metastatic stage. Neutrophil depletion during metastatic colonization caused a remarkable decrease in brain metastasis. Furthermore, we found that chronic exposure of nicotine recruited STAT3-activated N2-neutrophils that secreted exosomal miR-4466 in the brain. This pre-metastatic niche promoted stemness and metabolic switching via SKI/SOX2/CPT1A axis in the tumor cells thereby enabling brain metastasis. Importantly, exosomal miR-4466 levels were found to be elevated in serum/urine of cancer-free subjects with a smoking history and promote tumor growth in vivo, suggesting that exosomal miR-4466 may serve as a promising prognostic biomarker for predicting increased risk of metastatic disease among smoker(s). Our findings suggest a novel pro-metastatic role of nicotine-induced N2-neutrophils in the progression of brain metastasis. We also demonstrated that inhibiting nicotine-induced STAT3-mediated neutrophil polarization effectively abrogated brain metastasis in vivo. Our finding for the first time provides compelling evidence related to the mechanism(s) of neutrophil-mediated brain metastasis that arises from nicotine use. Our results also identified a potential prognostic biomarker for the onset of metastasis as a risk-reduction measure in lung cancer patients and implicated the risk of using nicotine gateway for smoking cessation in cancer patients with a smoking history. Citation Format: Abhishek Tyagi, Shih-Ying Wu, Sambad Sharma, Kerui Wu, Dan Zhao, Ravindra Deshpande, Kounosuke Watabe. Exosomal miR-4466 from nicotine-activated neutrophils promotes tumor cell stemness &amp; metabolism in brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5817.

Abstract 6370: Assessing the effect of blocking CCL2-CCR2 axis on breast cancer brain metastasis

Abstract Among the 300,000 newly diagnosed breast cancer patients every year, 5~20% of them will develop symptomatic brain metastasis, whose 1-year survival rate is lower than 20%. Our group previously reported that brain tumor microenvironment (TME)-mediated PTEN downregulation in brain metastatic tumor cells increases the secretion of the chemokine CCL2, which enhances the infiltration of CCR2+ bone marrow derived myeloid cells, eventually promoting brain metastasis outgrowth. However, the mechanism of CCL2-CCR2 axis promoting brain metastasis is not clear, and the efficacy of targeting either CCR2 or CCL2 remained to be assessed. Here we show that Ccr2 antagonism significantly blocked Ccr2high myeloid cells trafficking in the blood and infiltration into the brain TME. However, Ccr2 antagonism did not sufficiently impede breast cancer brain metastasis in multiple preclinical models. Nevertheless, knocking down CCL2 or targeting CCL2 exhibited significant inhibition of brain metastasis growth. Subsequent analysis of the brain TME through mass cytometry demonstrated dramatically decreased infiltration of both Ccr2high and Ccr2low myeloid cell populations in the CCL2 targeted group, implying that the Ccr2low myeloid cells are also involved in promoting brain metastasis growth. Our data highlights the differential responses between targeting CCR2 or CCL2 in multiple preclinical brain metastasis models, which direct us to explore the function of Ccr2low myeloid cells in regulating brain metastasis progression. Our findings also suggest that carefully choosing between CCR2 or CCL2 as a target to control brain metastasis is important in clinical practice. Citation Format: Yimin Duan, Yutao Qi, Lin Zhang, Xiangliang Yuan, Dihua Yu. Assessing the effect of blocking CCL2-CCR2 axis on breast cancer brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6370.

Selecting optimal timing of cranial radiotherapy-based on the graded prognostic assessment for lung cancer using molecular markers (Lung-molGPA) in patients with non-small cell lung cancer and brain metastases.

e21105 Background: The updated Graded Prognostic Assessment for Lung Cancer Using Molecular Markers (Lung-molGPA) index will provide more accurate prediction of expected survival for patients with advanced non-small cell lung cancer (NSCLC) with brain metastases (BM). This retrospective study aims to evaluate optimal timing of cranial radiotherapy (RT) in NSCLC patients with BM stratified by Lung-molGPA index. Methods: This study retrospectively screened patients with NSCLC and initially diagnosed BM in our cancer center between February 2012 and July 2018. These enrolled patients were scored and stratified based on lung-molGPA index. The primary endpoint was overall survival time (OS), defined as the interval from the initiation of BM diagnosis to death caused by any reason or the last follow-up. And the secondary endpoint was progression free survival (PFS), referred to the interval from the initiation of BM diagnosis to disease progression or death caused by any reason. The effect of radiotherapy timing on survival time in groups stratified by lung-molGPA index was evaluated. The early RT was defined as receiving RT within three months after initial diagnosis of BM with no progression of BM prior to RT. And the delayed RT was defined as receiving RT after progression of BM or initial diagnosis of BM three months later. Results: Overall, 471 patients were enrolled in our study, including 260 patients receiving RT. The median follow-up time was 48 months. In entire cohort, median OS time and PFS were 15.0 and 9.0 months, respectively. In lung-molGPA0-2 group, OS of patients with or without RT was no statistical difference (HR, 0.78, 95%CI, 0.59-1.04, P= .071). While in lung-molGPA2.5-4 group, the addition of RT could prolong OS and PFS of patients (OS: HR, 0.51, 95%CI, 0.39-0.67, P&lt; .001; and PFS: HR, 0.66, 95%CI, 0.51-0.85, P&lt; .001). Moreover, in patients scored as 2.5-4.0, the median OS of early RT and delayed RT was 24.0 months and 15.0 months, respectively, and OS of patients receiving early RT was significantly superior to patients receiving delayed RT (HR, 0.50, 95%CI, 0.31-0.79, P&lt; .001). While for patients scored as 0-2, no statistical difference was between OS of patients receiving early RT and delayed RT (HR, 0.75, 95%CI, 0.51-1.10, P= .115). Conclusions: With regards as patients scored 2.5-4.0 based on lung-molGPA index, early addition of cranial radiotherapy could benefit patients’ survival. While for patients scored 0-2, the survival benefit from cranial radiotherapy was limited.

Characterization of patients with metastatic melanoma that relapses following complete metabolic response from anti–PD-1 therapy.

9530 Background: Treatment with PD-1 inhibitor-based therapy has significantly improved survival in patients with metastatic melanoma over the past decade. Many of these patients achieve complete metabolic response (CMR) by FDG-PET/CT and electively stop treatment. However, the outcomes of patients who relapse after CMR remain uncertain. In this study, we attempt to further characterize metastatic melanoma patients who relapsed following elective discontinuation of anti-PD-1 based therapy due to CMR. Methods: We performed a single-center, retrospective analysis on a cohort of patients with metastatic or unresectable melanoma from 2012 to 2021 who were treated with anti-PD-1 monotherapy (pembrolizumab or nivolumab) or combination ipilimumab/nivolumab (I/N), with or without local therapies (surgery or radiation therapy). Patients who achieved a CMR from treatment were identified. CMR was defined as no evidence of metabolically active disease on full-body 18F-FDG-PET/CT and no evidence of new intracranial metastasis on MRI brain. Multiple clinical variables and survival outcomes were assessed. Results: Among 386 advanced stage melanoma patients analyzed, 87 achieved a CMR followed by elective treatment cessation with a median anti-PD-1 therapy duration of 10.4 months. 19/87 patients had brain metastasis at baseline. 17/87 patients had disease relapse with a median time to relapse from CMR of 12.1 months. Of those 17 patients, 8 received I/N, 9 received anti-PD-1 monotherapy, and 2 required local therapies to obtain CMR. 7/17 patients were able to achieve CMR again following resumption of anti-PD-1 monotherapy (n = 6) and BRAF/MEK targeted therapy (n = 1). 10/17 patients relapsed in the brain with 7 of those patients having no history of brain metastasis at baseline. Median overall survival after relapse from CMR was 34.1 months. The most common cause of death following relapse from CMR was brain metastasis progression (n = 5). Conclusions: A small proportion of metastatic melanoma patients who achieve complete metabolic (CMR) following treatment with anti-PD-1 therapy develop disease relapse. We found that relapse in the brain is common, regardless of baseline involvement at time of therapy, and is a common cause of mortality suggesting the importance of intracranial surveillance following treatment cessation. Ongoing studies are warranted to identify clinicopathologic factors that predict relapse to better inform patients and providers who elect to stop anti-PD-1 therapy.

Exosomal miR-4466 from nicotine-activated neutrophils promotes tumor cell stemness and metabolism in lung cancer metastasis

Smoking is associated with lung cancer and has a profound impact on tumor immunity. Nicotine, the addictive and non-carcinogenic smoke component, influences various brain cells and the immune system. However, how long-term use of nicotine affects brain metastases is poorly understood. We, therefore, examined the mechanism by which nicotine promotes lung cancer brain metastasis. In this study, we conducted a retrospective analysis of 810 lung cancer patients with smoking history and assessed brain metastasis. We found that current smoker’s lung cancer patients have significantly higher brain metastatic incidence compared to the never smokers. We also found that chronic nicotine exposure recruited STAT3-activated N2-neutrophils within the brain pre-metastatic niche and secreted exosomal miR-4466 which promoted stemness and metabolic switching via SKI/SOX2/CPT1A axis in the tumor cells in the brain thereby enabling metastasis. Importantly, exosomal miR-4466 levels were found to be elevated in serum/urine of cancer-free subjects with a smoking history and promote tumor growth in vivo, suggesting that exosomal miR-4466 may serve as a promising prognostic biomarker for predicting increased risk of metastatic disease among smoker(s). Our findings suggest a novel pro-metastatic role of nicotine-induced N2-neutrophils in the progression of brain metastasis. We also demonstrated that inhibiting nicotine-induced STAT3-mediated neutrophil polarization effectively abrogated brain metastasis in vivo. Our results revealed a novel mechanistic insight on how chronic nicotine exposure contributes to worse clinical outcome of metastatic lung cancer and implicated the risk of using nicotine gateway for smoking cessation in cancer patients.

Inhibition of Anti-Inflammatory Macrophage Phenotype Reduces Tumour Growth in Mouse Models of Brain Metastasis.

Breast cancer brain metastasis is a significant clinical problem and carries a poor prognosis. Although it is well-established that macrophages are a primary component of the brain metastasis microenvironment, the role of blood-derived macrophages (BDM) and brain-resident microglia in the progression of brain metastases remains uncertain. The aim of this study, therefore, was to determine the role, specifically, of pro- and anti-inflammatory BDM and microglial phenotypes on metastasis progression. Initial in vitro studies demonstrated decreased migration of EO771 metastatic breast cancer cells in the presence of pro-inflammatory, but not anti-inflammatory, stimulated RAW 264.7 macrophages. In vivo, suppression of the anti-inflammatory BDM phenotype, specifically, via myeloid knock out of Krüppel-like Factor 4 (KLF4) significantly reduced EO771 tumour growth in the brains of C57BL/6 mice. Further, pharmacological inhibition of the anti-inflammatory BDM and/or microglial phenotypes, via either Colony Stimulating Factor 1 Receptor (CSF-1R) or STAT6 pathways, significantly decreased tumour burden in two different syngeneic mouse models of breast cancer brain metastasis. These findings suggest that switching BDM and microglia towards a more pro-inflammatory phenotype may be an effective therapeutic strategy in brain metastasis.

Abstract PD4-04: Updated results of tucatinib vs placebo added to trastuzumab and capecitabine for patients with previously treated HER2-positive metastatic breast cancer with brain metastases (HER2CLIMB)

Abstract Background: Tucatinib is an oral tyrosine kinase inhibitor highly specific for HER2 that is approved for use in combination with trastuzumab and capecitabine in adults with advanced or metastatic HER2+ breast cancer, including patients with brain metastases, who have received one or more prior anti-HER2-based regimens in the metastatic setting. In the HER2CLIMB trial, the tucatinib regimen significantly prolonged progression-free survival (PFS) and overall survival (OS) in patients with HER2+ metastatic breast cancer (Murthy, NEJM 2020), including in patients with untreated, treated stable, and treated progressing brain metastases (Lin, J Clin Oncol, 2020). With an additional 15.6 months of follow-up, addition of tucatinib continued to show clinically meaningful prolongation of PFS and OS in the total study population (Curigliano, ASCO Meeting, 2021). We report updated results of exploratory efficacy analyses in patients with brain metastases. Methods: All patients in HER2CLIMB had a baseline brain MRI. Patients with brain metastases were eligible and classified as untreated, treated stable, or treated progressing. Patients were randomized 2:1 to receive tucatinib 300 mg twice daily or placebo, in combination with trastuzumab and capecitabine. Following the primary analysis, the protocol was amended to unblind sites to treatment assignment and allowed crossover from the placebo regimen to the tucatinib regimen. Efficacy analyses in patients with brain metastases at baseline were performed at approximately 2 years from the last patient randomized by applying RECIST 1.1 to the brain based on investigator evaluation. OS and CNS-PFS (progression in the brain or death) were evaluated in all patients with brain metastases. Patients without CNS-PFS events were censored at the last brain MRI. Confirmed intracranial (IC) objective response rate (ORR-IC) was evaluated in patients with measurable IC disease. Results: At a median follow-up of 29.6 months, median OS was 21.6 months vs 12.5 months in all patients with brain metastases (HR: 0.60; 95% CI: 0.44, 0.81), 21.4 months vs 11.8 months in patients with untreated/treated progressing brain metastases (HR: 0.52; 95% CI: 0.36, 0.77), and 21.6 months vs 16.4 months in patients with treated stable brain metastases (HR: 0.70; 95% CI: 0.42, 1.16). Median CNS-PFS was 9.9 months vs 4.2 months in all patients with brain metastases (HR: 0.39; 95% CI: 0.27, 0.56), 9.6 months vs 4.0 months in patients with untreated/treated progressing brain metastases (HR: 0.34; 95% CI: 0.22, 0.54), and 13.9 months vs 5.6 months in patients with treated stable brain metastases (HR: 0.41; 95% CI: 0.19, 0.85). ORR-IC was higher in the tucatinib arm (47.3%; 95% CI: 33.7, 61.2) vs the placebo arm (20.0%; 95% CI: 5.7, 43.7) for patients with brain metastases, and median duration of response (DOR) was 8.6 months (95% CI: 5.5, 10.3) vs 3.0 months (95% CI: 3.0, 10.3). Conclusions: With 15.6 months of additional follow-up, the tucatinib-trastuzumab-capecitabine regimen resulted in a robust and durable prolongation of OS for all patients with HER2+ metastatic breast cancer and brain metastases. Additionally, this benefit was maintained in patients with untreated/treated progressing and treated stable brain metastases. Treatment with tucatinib continued to show clinically meaningful benefit in CNS-PFS consistent with the primary analysis. Citation Format: Nancy U Lin, Rashmi K Murthy, Vandana Abramson, Carey Anders, Thomas Bachelot, Philippe Bedard, Virginia Borges, David Cameron, David Cameron, Lisa Carey, A Jo Chien, Giuseppe Curigliano, Michael DiGiovanna, Karen Gelmon, Gabriel Hortobagyi, Sara Hurvitz, Ian Krop, Sherene Loi, Sibylle Loibl, Volkmar Mueller, Mafalda Oliveira, Elisavet Paplomata, Mark Pegram, Dennis Slamon, Amelia Zelnak, Jorge Ramos, Wentao Feng, Eric Winer. Updated results of tucatinib vs placebo added to trastuzumab and capecitabine for patients with previously treated HER2-positive metastatic breast cancer with brain metastases (HER2CLIMB) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD4-04.

Abstract OT2-19-07: A phase I/Ib trial of the CDK4/6 antagonist ribociclib (RIB) and the HDAC inhibitor belinostat (BEL) in patients with metastatic triple negative breast cancer and recurrent ovarian cancer with response prediction by genomics (CHARGE)

Abstract Background: Cytotoxic chemotherapy is the mainstay of treatment in metastatic triple negative breast cancer (TNBC), a phenotype predictive of poor survival. Similarly, ovarian cancer is the leading cause of death from gynecologic malignancies and shares genomic similarities with TNBC. New treatment paradigms are needed for people with these malignancies. CDK4/6 (CDKi) and histone deacetylase (HDACi) inhibitors are promising treatment approaches in breast cancer though neither has been successfully translated as monotherapy in TNBC. HDACi have single-agent activity against TNBC in vivo, possibly through decreasing epithelial mesenchymal transition, migration, and metastases. CDKi cause cell cycle arrest and tumor regression in TNBC models. HDACi increase inhibitors of cell cycle progression including RB1, CDKN1A, CDKN1C, CDKN2B, and CDKN2D in TNBC in vitro. We hypothesized that HDACi would increase the sensitivity of breast cancer to CDKi. RIB + BEL demonstrated growth inhibition in TNBC cell lines with synergy seen at multiple doses. RIB and BEL are expected to be safe in combination. BEL has no effect on CYP3A4, the main metabolizing enzyme for RIB. Although RIB can inhibit CYP3A4, which partially metabolizes BEL, BEL is primarily metabolized by UGT1A1. Although both drugs can cause myelosuppression, thrombocytopenia occurs more often with BEL and leukopenia with RIB. The primary objective is to assess the maximum tolerated dose of RIB and BEL in combination. Secondary objectives include safety and efficacy. Exploratory objectives include development of a predictive biomarker, exploration of subclonal structure and phenotypic pathway activation through serial biopsies, and efficacy within RB1 mutation status subgroups. We hypothesized that RIB plus BEL will be well-tolerated and demonstrate activity in people with metastatic TNBC or recurrent ovarian cancer. Methods: This open-label, multi-center, phase I study follows a modified 3+3 dose escalation design allowing independent escalation of the dose of each of the agents with a 10 person expansion cohort at the Recommended Phase 2 Dose (RP2D). Dose escalation will be open to patients with TNBC or ovarian cancer and only TNBC will be enrolled at dose expansion. The first cohort uses RIB 200 mg daily and BEL 600 mg/m2 daily on days 1-5 of a 28 day cycle. Tumor is assessed at baseline and every 8 weeks. Biopsies occur at screening and cycle 2 day 15 to establish a predictive biomarker panel that will be validated with future study. Patients ≥ 18 years of age who have measurable and metastatic or unresectable disease are included. Patients previously treated with a CDKi or HDACi are excluded. Additional exclusion criteria include use of valproic acid during the study or within 5 days of the first dose of BEL, prolonged QTc, grade ≥2 unresolved diarrhea, or new or progressive brain metastases. Statistical analysis of safety data will be descriptive. Efficacy will be reported in the study population as well as in RB1 mutation status subgroups. PFS will be estimated using Kaplan-Meier methods. Cox regression will be used to determine if there is a relationship between biomarker predictor and PFS. The estimated duration for accrual is 18 months with patient participation of around 36 months. Enrollment began January 2021 with 2 patients currently enrolled. Clinical Trial registry Number: NCT04315233 Citation Format: Shashank Sama, Kristen Kelley, Christos Vaklavas, Andrea Bild, Kenneth Boucher, John Lamb, Julia Lehman, Philip Moos, Theresa Werner, Adam Cohen. A phase I/Ib trial of the CDK4/6 antagonist ribociclib (RIB) and the HDAC inhibitor belinostat (BEL) in patients with metastatic triple negative breast cancer and recurrent ovarian cancer with response prediction by genomics (CHARGE) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr OT2-19-07.

Neurooncological Challenges in Relapsing Intracranial Melanoma Metastases: A Case Report

Introduction: Treatment of melanoma brain metastases (MBM) is a complex interdisciplinary challenge. Relapsing MBMs pose an extra challenge due to limited therapeutic options and higher complication rate. Multiple surgical interventions and radiation can be indicated in the case of intracranial relapse with extracranial disease control under oncological therapy e.g., immunotherapy. Case Presentation: Here, we report on a 37-year-old female patient with stage IV metastatic melanoma, who underwent six neurosurgical procedures, including five tumor resections, and three courses of different irradiation protocols in 26 months, all while receiving multiple regimens of immunotherapy. Throughout the different therapies, the patient showed varying neurological deficits, including facial nerve palsy, hemiparesis and reduction of cognitive function. The patient died due to symptoms related to leptomeningeal spread of the tumor. Conclusion: With this case, we want to share our experience with multiple neurosurgical interventions and repeated brain irradiation procedures in a patient with relapsing MBM. Neurosurgical interventions contributed to symptom relief, saved steroids and potentially prolonged survival. Therefore, based on the events of this case, repeated surgery could be considered for progressive brain metastases.

Local, multimodal intralesional therapy renders distant brain metastases susceptible to PD-L1 blockade in a preclinical model of triple-negative breast cancer

Despite recent progress in therapeutic strategies, prognosis of metastatic triple-negative breast cancer (TNBC) remains dismal. Evidence suggests that the induction and activation of tumor-residing conventional type-1 dendritic cells (cDC1s) is critical for the generation of CD8+ T cells that mediate the regression of mammary tumors and potentiate anti-PD-1/PD-L1 therapeutic efficacy. However, it remains unknown whether this strategy is effective against metastatic TNBC, which is poorly responsive to immunotherapy. Here, using a mouse model of TNBC, we established orthotopic mammary tumors and brain metastases, and treated mammary tumors with in situ immunomodulation (ISIM) consisting of intratumoral injections of Flt3L to mobilize cDC1s, local irradiation to induce immunogenic tumor cell death, and TLR3/CD40 stimulation to activate cDC1s. ISIM treatment of the mammary tumor increased circulating T cells with effector phenotypes, and infiltration of CD8+ T cells into the metastatic brain lesions, resulting in delayed progression of brain metastases and improved survival. Furthermore, although anti-PD-L1 therapy alone was ineffective against brain metastases, ISIM overcame resistance to anti-PD-L1 therapy, which rendered these tumor-bearing mice responsive to anti-PD-L1 therapy and further improved survival. Collectively, these results illustrate the therapeutic potential of multimodal intralesional therapy for patients with unresectable and metastatic TNBC.