Progressive Brain Metastases Research Articles

A study method using early dynamic acquisition of [18F]fluorodopa positron emission tomography for the differential diagnosis between progression and radionecrosis of brain metastases after radiotherapy

BackgroundIt is difficult to distinguish between the brain metastasis progression (BMP) and brain radionecrosis (BRN) on the basis of 18F-3,4-dihydroxyphenylalanine positron emission tomography/computed-tomography (18F-FDOPA PET/CT) data. The advent of silicon photomultiplier (SiPM) PET technology makes it possible to study dynamic volumes and potentially improve diagnostic accuracy. We developed a method for processing 18F-FDOPA PET/CT in the differential diagnosis between BMP and BRN. The method involves a short (3-second) sampling time during a 4-minute acquisition on a SiPM-PET/CT machine. We prospectively included 15 patients and 19 metastases. All acquisitions were performed in list mode acquisition for 25 min on a four-ring SiPM PET/CT system. We calculated the ratios between the maximum activity in the lesion’s voxel and the mean activity in the contralateral region (VOImax/CLmean) or the mean activity in the white matter (VOImax/WMmean).ResultsSeven lesions were classified as BMP and twelve were classified as BRN. Statistically significant intergroup differences in the VOImax/CLmean and VOImax/WMmean activity ratios were observed for both the clinical volume and the early acquisition. The best performing quantitative variable was the VOImax/CLmean ratio on early acquisition, with a diagnostic accuracy of 94.7%, a sensitivity of 100%, and a specificity of 91.7%.ConclusionThe 18F-FDOPA PET/CT data acquired a few minutes after the bolus injection confirms its value in differentiating between BMP and BRN, compared to the much longer classic clinical protocol.

Lipocalin-2 promotes breast cancer brain metastasis by enhancing tumor invasion and modulating brain microenvironment.

Breast cancer is the leading cancer diagnosed in women globally, with brain metastasis emerging as a major cause of death, particularly in human epidermal growth factor receptor 2 positive and triple-negative breast cancer subtypes. Comprehensive understanding of the molecular foundations of central nervous system metastases is imperative for the evolution of efficacious treatment strategies. Lipocalin-2 (LCN2), a secreted iron transport protein with multiple functions, has been linked to the progression of breast cancer brain metastasis (BCBM). In primary tumors, LCN2 promotes the proliferation and angiogenesis of breast cancer cells, triggers the epithelial-mesenchymal transition, interacts with matrix metalloproteinase-9, thereby facilitating the reorganization of the extracellular matrix and enhancing cancer cell invasion and migration. In brain microenvironment, LCN2 undermines the blood-brain barrier and facilitates tumor seeding in the brain by modulating the behavior of key cellular components. In summary, this review meticulously examines the fuel role of LCN2 in BCBM cascade, and investigates the potential mechanisms involved. It highlights the potential of LCN2 as both a therapeutic target and biomarker, indicating that interventions targeting LCN2 may offer improved outcomes for patients afflicted with BCBM.

Nerve growth factor inducible (VGF) is a secreted mediator for metastatic breast cancer tropism to the brain.

Brain metastases are one of the most serious clinical problems in breast cancer (BC) progression, associated with lower survival rates and a lack of effective therapies. Thus, to dissect the early stages of the brain metastatic process, we studied the impact of brain organotropic BC cells' secretomes on the establishment of the brain pre-metastatic niche (PMN). We found that BC cells with specific tropism to the brain caused significant blood-brain barrier (BBB) disruption, as well as microglial activation, in both in vitro and in vivo models. Further, we searched for a brain-organotropic metastatic signature, as a promising source for the discovery of new biomarkers involved in brain metastatic progression. Of relevance, we identified VGF (nerve growth factor inducible) as a key mediator in this process, also impacting the BBB and microglial functions both in vitro and in vivo. In a series of human breast tumors, VGF was found to be expressed in both cancer cells and the adjacent stroma. Importantly, VGF-positive tumors showed a significantly worse prognosis and were associated with HER2 (human epidermal growth factor receptor 2) overexpression and triple-negative molecular signatures. Further clinical validation in primary tumors from metastatic BC cases showed a significant association between VGF and the brain metastatic location, clearly and significantly impacting on the prognosis of BC patients with brain metastasis. In conclusion, our study reveals a unique secretome signature for BC with a tropism for the brain, highlighting VGF as a crucial mediator in this process. Furthermore, its specific impact as a poor prognostic predictor for BC patients with brain metastasis opens new avenues to target VGF to control the progression of brain metastatic disease. © 2024 The Pathological Society of Great Britain and Ireland.

The role of immunotherapy in patients with lung cancer and brain metastases: a narrative review of the literature.

Worldwide, approximately half of the patients diagnosed with lung cancer (LC) will develop, simultaneously or asynchronously, brain metastases (BMs). The existence of BMs negatively affects the quality of life and constitutes a poor prognostic factor, linked with high mortality. Locoregional therapy with surgery or radiation is, until now, the treatment of choice, especially for symptomatic patients; however, both options are linked to a high complication rate. The question arising here is whether, in asymptomatic patients, the benefit outweighs the risk and whether an alternative method can be used to treat this special category of patients. Over the last decade, immune checkpoint inhibitors (ICIs) have represented a major breakthrough in the field of oncology, and several molecules have been approved as a treatment option for LC. This review tried to analyze the tumor microenvironment of both the primary lung tumor and the BMs in order to evaluate the intracranial activity of ICIs, outline the main challenges of including these agents in the treatment of LC with BMs, highlight the available information from the main clinical trials, and mark the potential positive effect of choosing a combination therapy. In conclusion, it appears that immunotherapy has a positive effect, inhibiting the progression of BMs, but more data should be published specifically for this category of patients.

Reirradiation of metastases of the central nervous system: part 1-brain metastasis.

Because of improved survival of cancer patients, more patients irradiated for brain metastases develop intracerebral recurrences requiring subsequent courses of radiotherapy. Five studies focused on reirradiation with whole-brain radiation therapy (WBRT) after initial WBRT for brain metastases. Following the second WBRT course, improvement of clinical symptoms was found in 31-68% of patients. Rates of neurotoxicity, such as encephalopathy or cognitive decline, were reported in two studies (1.4% and 32%). In another study, severe or unexpected adverse events were not observed. Survival following the second WBRT course was generally poor, with median survival times of 2.9-4.1 months. The survival prognosis of patients receiving two courses of WBRT can be estimated by a scoring tool considering five prognostic factors. Three studies investigated reirradiation with single-fraction stereotactic radiosurgery (SF-SRS) following primary WBRT. One-year local control rates were 74-91%, and median survival times ranged between 7.8 and 14 months. Rates of radiation necrosis (RN) after reirradiation were 0-6%. Seven studies were considered that investigated re-treatment with SF-SRS or fractionated stereotactic radiation therapy (FSRT) following initial SF-SRS or FSRT. One-year local control rates were 60-88%, and the median survival times ranged between 8.3 and 25 months. During follow-up after reirradiation, rates of overall (asymptomatic or symptomatic) RN ranged between 12.5% and 30.4%. Symptomatic RN occurred in 4.3% to 23.9% of cases (patients or lesions). The risk of RN associated with symptoms and/or requiring surgery or corticosteroids appears lower after reirradiation with FSRT when compared to SF-SRS. Other potential risk factors of RN include the volume of overlap of normal tissue receiving 12 Gy at the first course and 18 Gy at the second course of SF-SRS, maximum doses ≥40 Gy of the first or the second SF-SRS courses, V12 Gy >9 cm3 of the second course, initial treatment with SF-SRS, volume of normal brain receiving 5 Gy during reirradiation with FSRT, and systemic treatment. Cumulative EQD2 ≤100-120 Gy2 to brain, <100 Gy2 to brainstem, and <75 Gy2 to chiasm and optic nerves may be considered safe. Since most studies were retrospective in nature, prospective trials are required to better define safety and efficacy of reirradiation for recurrent or progressive brain metastases.

Brain metastases in clinical trial participants with KRAS-mutated advanced non-small cell lung cancer receiving docetaxel: Pooled data analysis

ObjectivesLimited data are available on central nervous system (CNS) efficacy with standard-of-care therapies for KRAS-mutated (KRASmut) advanced non-small cell lung cancer (NSCLC). The objective of this study was to investigate the incidence and progression of brain metastases in KRASmut advanced NSCLC treated with docetaxel using pooled data from historical clinical trials. Materials and MethodsData from phase 2/3 trials of docetaxel-containing regimens in advanced NSCLC were sourced from the Medidata platform. Analysis was restricted to stage IIIB-IV KRASmut NSCLC with disease progression after ≥ 1 systemic anticancer therapy. Participants with asymptomatic, treated, and stable brain metastases were included. Endpoints included 12-month CNS disease control rate (CNS-DCR) and CNS progression per Response Evaluation Criteria in Solid Tumors; progression-free survival (PFS); and overall survival (OS). Data were pooled and analyses stratified by baseline brain metastases status. ResultsA total of 595 participants were included in the analysis (62 [10%] with baseline brain metastases and 533 [90 %] without). Among participants with brain metastases, 17 (27.4 %) had CNS progression during docetaxel treatment and 12-month CNS-DCR was 75.8 %; 45 (8.4 %) participants without baseline brain metastases developed brain metastases during treatment. In an analysis restricted to patients with metastatic disease, outcomes with and without baseline brain metastases included: median PFS, 3.3 and 4.9 months (p < 0.005); 12-month PFS, 5 % and 16 %; median OS, 6.9 and 10.4 months (p < 0.005); and 12-month OS, 20 % and 44 %, respectively. ConclusionThese findings establish CNS progression rates with docetaxel in previously treated KRASmut advanced NSCLC and facilitate interpretation of data from ongoing randomized clinical trials of novel KRAS-targeted therapeutic strategies vs. docetaxel.

A Phase II Trial of Bevacizumab in Patients with Recurrent/Progressive Solid Tumor Brain Metastases That Have Progressed Following Whole-Brain Radiation Therapy.

Patients with solid tumor brain metastases that progress after whole-brain radiation have limited options. This prospective trial investigated the efficacy, safety, and tolerability of bevacizumab as salvage therapy in this population. Eligible patients received bevacizumab 10 mg/kg intravenously every 2 weeks until progression. The primary endpoint was radiologic response using Response Assessment in Neuro-Oncology (RANO) criteria. The secondary endpoints were progression-free survival (PFS), overall survival (OS), duration of response, and safety. Quality of life (QOL) was studied using the Functional Assessment of Cancer Therapy-Brain (FACT-Br) scale. Twenty-seven patients were enrolled, with twenty-four having evaluable data for response. The majority of histologies (n = 21, 78%) were breast cancer. The remaining histologies were non-small-cell lung cancer (n = 4, 15%), neuroendocrine cancer (n = 1, 3%), and papillary fallopian serous adenocarcinoma (n = 1, 3%). Eighteen patients had radiologic response, with two patients demonstrating partial response (8.33%) and sixteen patients demonstrating stable disease (66.7%). The median duration of response was 203 days. PFS at 6 months was 46%, median PFS was 5.3 m, and median OS was 9.5 m. Treatment was well tolerated, with six patients experiencing grade 3 lymphopenia and hypertension. There was one grade 3 thromboembolism. QOL was not negatively impacted. Bevacizumab is a safe and feasible salvage treatment with durable response and favorable overall survival for patients with progressive brain metastases after whole-brain radiation.

Phase II study of enasidenib in IDH2-mutated malignant sinonasal and skull base tumors.

TPS3183 Background: Advanced sinonasal malignancies are rare and heterogeneous cancers with limited therapeutic options. Tumor types include olfactory neuroblastoma (ONB), sinonasal undifferentiated carcinoma (SNUC) and large cell neuroendocrine carcinoma (LCNEC), chondrosarcoma, and sinonasal adenocarcinoma (SNAC). Pathogenic driver mutations in isocitrate dehydrogenases 1 and 2 ( IDH1 and IDH2) were identified first in glioma and myeloid malignancies. IDH1/2 enzymatic activity catalyzes conversion of isocitrate and NADP+ to α-ketoglutarate (α-KG) and NAPDH, which are critical for cellular metabolism and for α-KG-dependent dioxygenases; mutant IDH1/2 catalyze conversion of α-KG to the oncometabolite 2-hydroxyglutarate (2-HG), a competitive antagonist of α-KG in regulating dioxygenases activity, with subsequent impact on DNA histone methylation and cellular differentiation. R172S or R172T IDH2mut have been detected in up to 80% of SNUCs and in a minority of ONB, chondrosarcoma, LCNEC and SNAC. Enasidenib is an oral small molecule inhibitor of the mutant IDH2 protein which prevents 2-HG accumulation and releases cancer cells from the differentiation block. It is currently approved for relapsed/refractory IDH2mut myeloid malignancies with proven clinical efficacy. Methods: This is a phase 2, single arm clinical trial conducted at the Center for Cancer Research (CCR) of the National Cancer Institute. The trial investigates the activity of enasidenib in adult patients with histologically or cytologically confirmed locally advanced or metastatic IDH2mut sinonasal cancers (SNUC, ONB, LCNEC, chondrosarcoma, SNAC). Participants must have RECIST 1.1 measurable disease and must have progressed following at least one prior systemic treatment line administered in the recurrent/metastatic setting; those with locally advanced disease must not be amenable to potentially curative approaches. Participants must also have ECOG performance status ≤ 2, be 18 years old or higher, and have adequate organ function. Participants with active, either new or progressive brain metastases or leptomeningeal disease are excluded. Enasidenib will be given continuously at a fixed dose of 100 mg orally daily in a 28-day cycle, until disease progression, unacceptable toxicity, or consent withdrawal. Imaging will be performed every 8 weeks. Baseline and on-treatment research biopsies will be mandatory, where clinically feasible. The trial aims to accrue a total of 25 participants. The primary end point is progression free survival. Secondary outcomes include safety, overall survival, and clinical benefit rate, defined as complete response, partial response and stable disease (per RECIST 1.1) lasting above 4 months. Correlative studies include evaluating changes in 2-HG plasma levels during treatment, and transcriptomic profiling. The study has just started enrolling in the CCR. Clinical trial registry: NCT06176989. Clinical trial information: NCT06176989 .

A phase II trial combining SHR-1316, bevacizumab, and cisplatin/carboplatin in patients with TNBC with active brain metastases.

e13133 Background: Triple-negative breast cancer (TNBC) has a high risk of brain metastases (BM), leading to poor survival. Treatment options for BMs are limited, and the combination of chemotherapy and immune checkpoint inhibitor is the standard-of-care for PD-L1 positive metastatic TNBC. Platinum-based systematic therapy is the mainstay of TNBC treatment and the addition of bevacizumab has shown improvement in the progression-free survival (PFS) of patients with BM. Therefore, this study aims to investigate the efficacy and safety of SHR-1316 (anti-PD-L1) in combination with bevacizumab and cisplatin/carboplatin in TNBC patients with BMs. Methods: In this single-center phase II trial, TNBC patients with active BM received SHR-1316, bevacizumab, and cisplatin/carboplatin. Prior treatment with bevacizumab or anti-PD-1/PD-L1 were not allowed. Prior platinum was allowed only in cases of previous platinum-sensitive response. The primary endpoint was objective response rate (ORR) of central nervous system (CNS), as assessed according to the response assessment in neuro-oncology brain metastases. The secondary endpoint included clinical benefit rate (CBR) of CNS, PFS, overall survival (OS), first progression site and safety. Results: As of January 12th, 2024, a total of 23 female patients with ECOG PS≥1(100%) were enrolled. The median number of previous lines of therapy for metastatic disease was 1 (0-3). All patients had active BM, of which 87% (20/23) were BM treatment-naïve and 13% (3/23) had BM progression after previous local therapy, 26.1% (6/23) had received a prior platinum agent. Of the 23 evaluable patients, the confirmed CNS ORR was 65.2% (95%CI: 42.7%-83.6%), with 3 complete response (CR), 12 partial response (PR), 7 stable disease (SD), and 1 progressive disease (PD). The median CNS-PFS was 11.2 months (95%CI, 5.8 to not reached), median PFS was 7.6 months (95%CI, 5.7-11.9), and median OS was 13.2 months (95%CI, 9.5 to not reached). Treatment-related adverse events (TRAEs) were reported in all 23 patients, and the most common TRAEs were neutrophil count decreased (69.6%, 16/23), anemia (65.2%, 15/23), asthenia (60.9%, 14/23), Hypomagnesaemia (56.5%, 13/23), leukopenia (52.2%, 12/23) and electrocardiogram T wave abnormal (52.2%, 12/23). The incidence of grade ≥3 TRAEs was 43.5% (10/23), including neutropenia (13%, 3/23), platelet count decreased (8.7%, 2/23), and hypertension (8.7%, 2/23). Only one patient had a grade 4 TRAE (lymphocytopenia), and SHR-1316 related serious adverse event (facial nerve disorder) occurred in only one patient. No grade 5 AEs were noted. Conclusions: SHR-1316 plus bevacizumab and cisplatin/carboplatin achieves a significant improvement in CNS ORR and brings PFS and OS benefits in TNBC patients with active BMs. As an effective and safe treatment, this triple-combination warrants further investigation. Clinical trial information: NCT04303988 .

An Evaluation of Risk Factors for Intracranial Metastases of Sarcomas: A Systematic Review and Meta-Analysis

Sarcomas, a group of neoplasms comprising both tissue and bone soft tissue tumors, has an increasing prevalence in recent years. Prognosis significantly hinges on early detection and if not detected early may consequently metastasize. This review will be the first systematic review and meta-analysis characterizing the presentation and progression of brain metastases from bone and soft tissue cancers. The PubMed, Scopus, and Web of Science databases were queried to identify studies reporting the incidence of intracranial brain metastases from primary sarcoma to the present. Abstract and full-text screening of 1822 initial articles returned by preliminary search yielded 28 studies for inclusion and data extraction. Qualitative assessment of the studies were conducted in accordance with the Newcastle-Ottawa Scale criteria. Meta-analyses were applied to assess risk factors on outcomes. The average age within the cohort was 27.9 years with a male and female prevalence of 59.1% and 40.9%, respectively. The odds rato for living status (dead/alive) were calculated for several risk factors - male/female [OR 1.14, 95% CI 0.62, 2.07], single/multiple metastases [OR 0.67, 95% CI 0.35, 1.28], lung metastases/not [OR 1.63, 95% CI 0.85, 3.13], surgery/no surgery [OR 0.49, 95% CI 0.20, 1.21]. The standardized mean differences for duration from diagnoses to metastases were likewise analyzed - male/female [SMD 0.13, 95% CI -0.15, 0.42], single/multiple metastases [SMD 0.11, 95% CI -0.20, 0.42], lung metastases/not [SMD -0.03, 95% CI -0.38, 0.32], surgery/no surgery [SMD 0.45, 95% CI -0.18,1.09]. The standardized mean differences for duration from metastases to death were analyzed - lung metastases/not [SMD 0.43, 95% CI -0.08, 0.95]. Our study observed no statistically significant differences in mortality rate among several patient risk factors. Consequentially, there lacks a clear answer as to whether or not an association between mortality rates exists with these patient factors. As such, it is important to continue research in brain-metastasizing sarcomas despite their relative rarity.

Abstract PO2-04-05: FINAL OUTCOME ANALYSIS FROM THE PHASE II TUXEDO-1 TRIAL OF TRASTUZUMAB-DERUXTECAN IN HER2-POSITIVE BREAST CANCER PATIENTS WITH ACTIVE BRAIN METASTASES

Abstract Background Brain metastases (BM) are a severe complication of HER2-positive metastatic breast cancer. In the absence of any immediate indication for local therapy, the tyrosine-kinase inhibitor tucatinib combined with trastuzumab and capecitabine (TTC) is regarded as the preferred systemic treatment option for active BM, while data on the activity of antibody-drug conjugates (ADC) is limited. In the primary outcome analysis of TUXEDO-1, an intracranial response rate (RR) of 73.3% was reported with the ADC trastuzumab-deruxtecan (T-DXd). Here, we report final progression-free survival (PFS) and overall survival (OS) results of this study. Patients and Methods: TUXEDO-1 is a prospective, single-centre, single-arm phase 2 trial. Adult patients with HER2-positive BC and active BM (newly diagnosed untreated or progressing after prior local therapy), prior treatment with trastuzumab and pertuzumab, ECOG performance status 0 or 1 without indication for immediate local therapy were accrued and received T-DXd until progression, inacceptable toxicity, or withdrawal for any other reason. The primary endpoint was intracranial RR centrally assessed by Response Assessment in Neuro-Oncology (RANO)-BM criteria in the intention-to-treat population; secondary endpoints included PFS, OS, safety, quality-of-life (QoL), and neurocognitive function. PFS and OS were estimated with the Kaplan-Meier method and analysed in the per-protocol population (PPP). Results A total number of 15 patients were accrued; one patient was found to have dural metastases only upon restaging, resulting in a PPP of 14 patients. Patients had received a median number of two prior treatment lines (range, 1-5), 60% had progressive brain metastases and 60% had received prior T-DM1. At 26.5 months median follow-up, median PFS was 21 months (95% CI 13.3-n.r.) and median OS was not reached (95% CI 22.2-n.r.). A total of 238 cycles of T-DXd were administered (median 11.5 cycles; range 4-42). With longer follow-up, no new safety signals were observed. The most common grade 3 adverse event (AE) was fatigue (n=3; 20%). A total of 8 serious AEs were reported in 8 patients. Grade 2 interstitial lung disease and a grade 3 symptomatic drop of left-ventricular ejection fraction were observed in one patient each. QoL and neurocognitive functioning were maintained over the entire treatment duration and a significant deterioration of global QoL was observed upon progression (p=0.036). Most patients received TTC (n=5) or local therapy (n=4) as next subsequent treatment line. Ancillary biomarker studies are ongoing, and results will be presented at the meeting. Discussion In TUXEDO-1, T-DXd yielded prolonged intra- and extracranial disease control in patients with active HER2-positive breast cancer BM. The safety profile was consistent with previous reports. T-DXd did not impair QoL and neurocognitive functioning was maintained. Results therefore support the concept of ADCs as systemic therapy for active BM. Citation Format: Rupert Bartsch, Anna Sophie Berghoff, Julia Furtner, Maximilian Marhold, Elisabeth Sophie Bergen, Sophie Roider-Schur, Angelika Maria Starzer, Maximilian Mair, Heidrun Forstner, Beate Rottenmanner, Marie-Bernadette Aretin, Karin Dieckmann, Zsuzsanna Bago-Horvath, Helmuth Haslacher, Georg Widhalm, Aysegül Ilhan-Mutlu, Christoph Minichsdorfer, Thorsten Fuereder, Thomas Szekeres, Leopold Oehler, Birgit Gruenberger, Georg Pfeiler, Christian F. Singer, Ansgar Weltermann, Luzia Berchtold, Matthias Preusser. FINAL OUTCOME ANALYSIS FROM THE PHASE II TUXEDO-1 TRIAL OF TRASTUZUMAB-DERUXTECAN IN HER2-POSITIVE BREAST CANCER PATIENTS WITH ACTIVE BRAIN METASTASES [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-04-05.

Abstract PO3-04-06: A comparison of the efficacy of trastuzumab deruxtecan in advanced HER2-positive breast cancer: active brain metastasis versus progressive extracranial disease alone

Abstract Background Trastuzumab deruxtecan (T-DXd) has demonstrated efficacy in patients with brain metastasis (BM), a group historically with poor outcomes. The prevalence of BMs in patients commencing T-DXd is currently unknown. To date, no direct comparisons have been made of the activity of T-DXd in patients with active BM versus those with extracranial progression alone. This real-world study explored the prevalence of BMs at commencement of T-DXd, the efficacy of T-DXd in active BM versus extracranial progression alone and the safety of T-DXd. Methods Patients with HER2-positive advanced breast cancer treated with T-DXd between June 2021 and February 2023 at our specialist cancer hospital were identified and notes reviewed. Clinico-pathological information, prior treatment, the presence or absence of CNS disease, outcomes and treatment-emergent adverse events (TEAE) were recorded. Data cut-off was 28th February 2023. Results 29 female patients: 16 extracranial disease alone, 12 BM and 1 LMD were identified. Prevalence of BM at commencement of T-DXd was 41% (12 of 29). Median age was 52 (IQR 44-62), with a median 2 (range 2-6) prior lines of HER2 directed and chemotherapy:86% (25 of 29) had received prior trastuzumab and pertuzumab, 100% (29 of 29) T-DM1 and 3% (1 of 29) patient trastuzumab duocarmazine. At a median follow-up of 13.8 months, median progression free survival (PFS) for overall population was 13.9 months (95% CI: 12.4-NE), 16.1 months (95% CI: 15.1-NE) for active BMs, and 12.4 months (95% CI: 8.3-NE) for progressive extracranial disease alone (P=0.106). 12-month OS rate was 74% (95% CI: 59-95) in the overall population, 83% (95% CI: 58-100) and 66% (95% CI: 45-96) for active BMs, and extracranial only disease respectively (P=0.678). Objective response rates: overall population was 69% (95% CI: 52-86), active BMs was 60% (95% CI: 30-90), and progressive extracranial disease alone was 69% (95% CI: 46-91). 6% (1 of 16) with extracranial disease alone developed BM during treatment with T-DXd. Reasons for treatment discontinuation: 67% (10 of 15) disease progression or death; 33% (5 of 15) toxicity. 48% (14 of 29) remain on treatment. Most common TEAEs were fatigue (97%; 28 of 29), alopecia (76%; 22 of 29), and constipation (72%; 21 of 29). Pneumonitis occurred in 9 patients (31%, included 2 deaths). 1 pathologically confirmed case of radionecrosis was documented. An updated analysis with an additional 9 patients who commenced T-DXd since February 2023 will be presented. Conclusion In this real-world study a significant number of patients had BM at the commencement of T-DXd. We demonstrate that in advanced HER2 positive breast cancer that T-DXd is as effective, in terms of PFS and OS, in active BMs as it is in progressive extracranial disease alone. These data provide the first evidence that in contrast to the historical data that active BM may no longer be a detriment to survival as compared to progressive extracranial disease alone when treated with T-Dxd. These observations warrant further investigations in larger series. The high rate of pneumonitis warrants further consideration. Citation Format: James Pearson, Adeel Khan, Talvinder Bhogal, Helen Wong, Andrea Law, Samantha Mills, Nuria Santamaria, Joanne Cliff, Douglas Errington, Allison Hall, Clare Hart, Zafar Malik, Raj Sripadam, Helen Innes, Helen Flint, Gabriella Langton, Eliyaz Ahmed, Jill Bishop, Richard Jackson, Carlo Palmieri. A comparison of the efficacy of trastuzumab deruxtecan in advanced HER2-positive breast cancer: active brain metastasis versus progressive extracranial disease alone [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-04-06.

Short-term predictors of stereotactic radiosurgery outcome for untreated single non-small cell lung cancer brain metastases: a restrospective cohort study.

Stereotactic radiosurgery (SRS) is an option for brain metastases (BM) not eligible for surgical resection, however, predictors of SRS outcomes are poorly known. The aim of this study is to investigate predictors of SRS outcome in patients with BM secondary to non-small cell lung cancer (NSCLC). The secondary objective is to analyze the value of volumetric criteria in identifying BM progression. This retrospective cohort study included patients >18 years of age with a single untreated BM secondary to NSCLC. Demographic, clinical, and radiological data were assessed. The primary outcome was treatment failure, defined as a BM volumetric increase 12 months after SRS. The unidimensional measurement of the BM at follow-up was also assessed. One hundred thirty-five patients were included, with a median BM volume at baseline of 1.1 cm3 (IQR 0.4-2.3). Fifty-two (38.5%) patients had SRS failure at follow-up. Only right BM laterality was associated with SRS failure (p=0.039). Using the volumetric definition of SRS failure, the unidimensional criteria demonstrated a sensibility of 60.78% (46.11%-74.16%), specificity of 89.02% (80.18%-94.86%), positive LR of 5.54 (2.88-10.66) and negative LR of 0.44 (0.31-0.63). SRS demonstrated a 61.5% local control rate 12 months after treatment. Among the potential predictors of treatment outcome analyzed, only the right BM laterality had a significant association with SRS failure. The volumetric criteria were able to identify more subtle signs of BM increase than the unidimensional criteria, which may allow earlier diagnosis of disease progression and use of appropriate therapies.

Anti-EGFR ScFv functionalized exosomes delivering LPCAT1 specific siRNAs for inhibition of lung cancer brain metastases.

Brain metastasis (BM) is one of the leading causes of cancer-related deaths in patients with advanced non-small cell lung cancer (NSCLC). However, limited treatments are available due to the presence of the blood-brain barrier (BBB). Upregulation of lysophosphatidylcholine acyltransferase 1 (LPCAT1) in NSCLC has been found to promote BM. Conversely, downregulating LPCAT1 significantly suppresses the proliferation and metastasis of lung cancer cells. In this study, we firstly confirmed significant upregulation of LPCAT1 in BM sites compared to primary lung cancer by analyzing scRNA dataset. We then designed a delivery system based on a single-chain variable fragment (scFv) targeting the epidermal growth factor receptor (EGFR) and exosomes derived from HEK293T cells to enhance cell-targeting capabilities and increase permeability. Next, we loaded LPCAT1 siRNA (siLPCAT1) into these engineered exosomes (exoscFv). This novel scFv-mounted exosome successfully crossed the BBB in an animal model and delivered siLPCAT1 to the BM site. Silencing LPCAT1 efficiently arrested tumor growth and inhibited malignant progression of BM in vivo without detectable toxicity. Overall, we provided a potential platform based on exosomes for RNA interference (RNAi) therapy in lung cancer BM.

Abstract 5515: Low body mass index (BMI) induces neuronal NPY and promotes brain metastasis of lung cancer

Abstract Brain metastases (BrMs) are a common occurrence in lung cancer with a dismal outcome. To develop a more effective therapeutic strategy, it is crucial to understand the underlying pathological mechanism of brain metastasis. Recent clinical data has unveiled a significant association between low body mass index (BMI) and an increased risk of brain metastasis in lung cancer patients, leading to reduced survival rates compared to other primary tumors. However, the molecular mechanism underlying this paradoxical relationship, often referred to as the "obesity paradox," in the context of lung cancer mortality presents a complex and intriguing puzzle and warrants in-depth investigation. Here, we examined biological mechanism of how low BMI promotes lung cancer brain metastasis. In this study, we conducted a retrospective pan-analysis of 5,516 patient cohorts with brain metastasis originating from lung, breast, melanoma, and renal cancers with their BMI status. We found that lung cancer patients with low BMI have significantly higher brain metastatic incidence compared to the high BMI patients, in contrast to breast, melanoma, and renal cancers. Furthermore, we found that low BMI plays a pivotal role in mediating neuron activation within the brain and that the secretion of neuronal neuropeptide Y (NPY), a protein involved in appetite and energy homeostasis via GHSR-receptor manner, promotes metabolic switching through NPY/NPY5R axis in the tumor cells in the brain thereby enabling metastasis. Elevated levels of neuronal NPY in the brains of cancer-free subjects with low BMI suggest its potential utility as a promising prognostic biomarker for identifying the increased risk of metastatic disease in lung cancer patients with low BMI. We also demonstrated that reversing low BMI or blocking the NPY/Y5R interactions effectively abrogated brain metastasis in our animal model. Our findings suggest a novel pro-metastatic role of low BMI-induced NPY in the progression of brain metastasis. We emphasize the importance of elucidating the clinical implications of this relationship to develop an updated intervention strategy for the clinical care of patients with lung cancer and low BMI. Citation Format: Abhishek Tyagi, Shih-Ying Wu, Ravindra Deshpande, Kerui Wu, Liang Liu, Kounosuke Watabe. Low body mass index (BMI) induces neuronal NPY and promotes brain metastasis of lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5515.

Abstract 1961: Discovery of a highly potent and brain penetrant fourth generation EGFR tyrosine kinase inhibitor

Abstract Third generation EGFR tyrosine kinase inhibitors (TKIs) such as Osimertinib have emerged as first-line standard of care therapy to treat non-small cell lung cancer (NSCLC) patients with activating EGFR mutations (del19, L858R or T790M). However, within 12 to 18 months following treatment, 15-20% of the patients develop C797S mutation, which drives resistance to these drugs; with the progression of disease brain metastasis is observed in 40-70% of the EGFRm+ NSCLC patients. Here, we report a highly potent and brain penetrant fourth generation EGFR-TKI ACE-34237307, designed to overcome C797S mutation (del19/C797S and L858R/C797S), and common single point mutations (del19 and L858R). ACE-34237307 is also designed to potently inhibit the more prevalent non-canonical EGFR mutations such as G719S and L861Q. ACE-34237307 showed robust anti-proliferative activity against EGFR double mutations in Ba/F3 (EGFR-del19/C797S and EGFR-L858R/C797S) cell lines with IC50 values of 0.1 and 0.23 nM, respectively. In phospho-EGFR assay, ACE-34237307 demonstrates over 79-fold selectivity against A431 (EGFR-WT) cell line when compared to PC-9 (EGFR-del 19) cell line. ACE-34237307 is highly brain penetrant with B/P ratio of 2.3 in rat and 1.2 in mouse. It has an excellent pharmacokinetic profile in rat, mouse and dog with good bioavailability, a flat PK curve and reduced Cmax, which will translate to a better safety profile. The in vivo anti-tumor efficacy was evaluated in Osimertinib resistant double mutant Ba/F3-EGFR-del19/C797S and L858R/C797S as well as del19 and L858R single mutant xenograft models. It has been shown that ACE-34237307 at doses of ≥ 0.6 mg/kg induces complete tumor regression or eradication in all tumor models tested. In brain tumor models with Ba/F3 (EGFR-del19/C797S) and PC-9 (EGFR-del19), ACE-34237307 showed complete inhibition or eradication of brain tumors and drastically extended animal survival at ≥ 0.6 mg/kg. In summary, ACE-34237307 is a potent fourth generation EGFR-TKI with high WT selectivity, excellent brain penetration, highly favorable DMPK profile, outstanding in vivo efficacy in subcutaneous and brain tumor models and low projected human dose amenable to QD dosing. Citation Format: sanjeev kumar, junmei wang, wenqian li, weitao pan, zhiming wen, Kuo-Long yu, Genshi Zhao, tinggui yin. Discovery of a highly potent and brain penetrant fourth generation EGFR tyrosine kinase inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1961.

Abstract 4031: P-selectin as an emerging target for the treatment of primary and secondary brain tumors

Abstract Glioblastoma (GB) is an aggressive type of brain cancer with a high mortality rate. It is a highly angiogenic tumor exhibiting an extremely invasive nature. As such, its brain microenvironment plays a crucial role in its progression. Microglia are the brain resident immune cells that have been shown to facilitate GB cell invasion and immune suppression. The mechanism by which GB cells alter microglia behavior is yet to be fully understood. One proposed mechanism involves adhesion molecules such as the Selectins family of proteins which are expressed on the surface of endothelial and immune cells and are involved in immune modulation and cancer immunity. We have previously shown that one member of the Selectin family, P-Selectin (SELP), is expressed by GB cells. Here, we investigated the functional role of SELP in GB-microglia interactions. First, we found that microglia cells facilitate the expression and secretion of SELP by GB cells, and that GB cells facilitate the expression of P-Selectin ligand-1 (PSGL-1) by Glioma-associated microglia/macrophages (GAMs). We then showed that SELP mediates GAMs-enhanced GB invasion and proliferation in our unique 3D-bioprinted ex vitro models and has a role in GAMs activation state. These findings were validated in vivo, showing that inhibition or downregulation of SELP leads to reduced tumor growth, increased overall survival, and improved immune response. Single-cell RNA-seq analysis of the tumors revealed an increase in pro-inflammatory GAMs signature, reduction in cancer cell tumorigenesis potential, and improved T cell activation. Thus, combining SELP inhibition with other immune checkpoint inhibitors, such as anti-PD-1, may have a synergistic effect by harnessing both the innate and the adaptive immune systems against the tumor. Furthermore, we found SELP/PSGL-1 axis to be involved in the progression of brain metastasis originating from melanoma, and breast, and lung cancer. Thus, we have begun an investigator-initiated clinical trial, testing the efficacy of the anti-SELP antibody, Crizanlizumab, alone or in combination with anti-PD-1 antibody, Nivolumab, for GB and melanoma brain metastasis patients (NCT05909618). Crizanlizumab, approved by the FDA and EMA for sickle cell pain crisis (VOC, Vaso-Occlusive Crisis) of sickle-cell anemia patients, was proven to be safe for human use, and efficient in inhibiting SELP function. As such, it has the potential to reduce tumor burden and improve patient outcomes. This work can improve our understanding of GAMs function, which may pave the way for new and effective treatments for primary and secondary brain tumors. Citation Format: Eilam Yeini, Ronnie Frommer-Shapira, Alisa Talianski, Paula Ofek, Sabina Pozzi, Nitzan Albeck, Dikla Ben-Shushan, Galia Tiram, Sapir Golan, Ron Kleiner, Ron Sheinin, Shlomit Reich-Zeliger, Rachel Grossman, Zvi Ram, Henry Brem, Thomas M. Hyde, Prerna Magod, Dinorah Friedmann-Morvinski, Asaf Madi, Ronit Satchi-Fainaro. P-selectin as an emerging target for the treatment of primary and secondary brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4031.

Abstract 1768: Investigating oncogene amplifications in brain metastasis of esophageal adenocarcinoma samples

Abstract Esophageal Adenocarcinoma (EAC) exhibits a rising incidence and dismal survival rate in the US, primarily attributed to frequent distant metastases. Brain metastasis, though uncommon is an aggressive tumor type, remains poorly understood in EAC. To address this knowledge gap, we conducted a comprehensive analysis of 9 brain metastasis samples, profiling their whole-genome with matched normal and comparing them to the primary EAC tumors, other EAC metastasis types and other brain metastasis types, including the Hartwig Institute and PCAWG. Overall, our sample size comprised over 4,500 tumor whole-genome data and we utilized a uniform data analysis pipeline for robust comparisons between cohorts. Our analysis revealed that brain metastasis samples have significantly higher single-nucleotide variants, however, the structural variant burden in brain metastases closely resembled those observed in the primary tumor. Notably, the incidence of whole genome doubling is significantly higher in brain metastasis compared to other primary cancer types and metastases. This significant difference stems from the higher WGD incidence in primary EACs compared to other tumor types. Mutational signature analysis revealed no significant changes compared to the primary tumor, and we observed an enrichment of SBS 17a/b, previously associated with tumor progression in primary esophageal adenocarcinoma, along with a prevalent presence of the APOBEC mutagenesis signature in most samples. Notably, ERBB2 and TP53 emerged as prominent driver genes present in most brain metastasis samples. We also observed an upregulation of ERBB2 expression in brain metastasis samples. Interestingly, ERBB2 appeared to play a more significant role in brain metastasis progression compared to the primary tumor and other metastasis types, suggesting its potential as a therapeutic target. These findings advance our comprehension of brain metastasis in EAC, providing crucial insights into genomic alterations and mutational processes that could inform future therapeutic strategies and clinical management for this previously understudied metastatic type. Citation Format: Nora Lawson, Lingqun Ye, Bo Zhao, Andy Futreal, Kadir Akdemir. Investigating oncogene amplifications in brain metastasis of esophageal adenocarcinoma samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1768.

Contrast Clearance Analysis (CCA) to Assess Viable Tumour following Stereotactic Radiosurgery (SRS) to Brain Metastasis in Non-Small Cell Lung Cancer (NSCLC).

Brain metastases are common in lung cancer and increasingly treated using targeted radiotherapy techniques such as stereotactic radiosurgery (SRS). Using MRI, post-SRS changes may be difficult to distinguish from progressive brain metastasis. Contrast clearance analysis (CCA) uses T1-weighted MRI images to assess the clearance of gadolinium and can be thus used to assess vascularity and active tumours. We retrospectively assessed CCAs in 62 patients with non-small cell lung cancer (NSCLC) undergoing 104 CCA scans in a single centre. The initial CCA suggested the aetiology of equivocal changes on standard MRI in 80.6% of patients. In all patients whose initial CCA showed post-SRS changes and who underwent serial CCAs, the initial diagnosis was upheld with the serial imaging. In only two cases of a presumed progressive tumour on the initial CCA, subsequent treatment for radionecrosis was instigated; a retrospective review and re-evaluation of the CCAs show that progression was reported where a thin rim of rapid contrast clearance was seen, and this finding has been subsequently recognised as a feature of post-treatment change on CCAs. The lack of concordance with CCA findings in those who underwent surgical resection was also found to be due to the over-reporting of the thin blue rim as disease in the early cases of CCA use and, in three cases, potentially related to timelines longer than 7 days prior to surgery, both factors being unknown during the early implementation phase of CCA at our centre but subsequently learned. Our single-centre experience shows CCA to be feasible and useful in patients with NSCLC in cases of diagnostic uncertainty in MRI. It has helped guide treatment in the majority of patients, with subsequent outcomes following the implementation of the treatment based on the results, suggesting correct classification. Recommendations from our experience of the implementation include the careful consideration of the thin rim of the rapid contrast clearance and the timing of the CCA prior to surgery for suspected brain metastasis progression.

Abstract PR-006: Brain metastases roadmap reveals conserved regulatory dynamics rooted in dormant tumor cells

Abstract Capturing comprehensive brain metastasis landscape is critical to the establishment of effective anti-tumor strategies. This study took advantage of single cell multiomics sequencing to profile the molecular and cellular dynamics in tumor cells and associated microenvironment during brain metastasis. Among different primary cancer types, our data suggest that there are conserved yet distinct tumor cell subpopulations, governed by specific changes in gene expression, chromatin accessibility and tumor-stroma interactions. We characterized the conserved tumor subpopulations of brain metastasis with features of: (1) dormancy, (2) enhanced translation and migration, (3) epithelial to mesenchymal transition and (4) high proliferation rate. In line with previous observations, dormant cells exhibit distinct stimulation for interferon and oxidative phosphorylation. Furthermore, our data suggest that dormant tumor cells increase amino acids metabolism and antigen presentation by upregulating HLA class molecules. Stromal and tumor cells interaction network analysis predicted most active ligands that might shape intratumoral heterogeneity. For example, TGFβ signaling induced by immune cells and astrocytes is associated with tumor cell epithelial to mesenchymal transition. Additionally, results suggest the vascular endothelial niche supports brain metastasis proliferation. Interestingly, dormant tumor cells appear to limit cell-cell interactions with the surrounding microenvironment when compared to other tumor cells subpopulations. Despite pronounced cell plasticity, trajectory analysis uncovered a cell progression pattern and its major sequential states and driving genes. Notably, the trajectory embarked with dormant tumor cells at its root and ended with a prevalence of rapidly proliferating tumor cells. As cycling cancer cells arise, we observed a disruption in circadian rhythm regulators activities, indicating that altered circadian regulation may contribute to brain metastasis progression. This work demonstrated that despite a pronounced intratumoral heterogeneity, brain metastases present conserved tumor subpopulations regardless of the patient and primary type. Importantly, the tumor trajectory provides new insights into the regulatory landscape controlling the transition from dormant to proliferating tumor cells. A novel and key finding in this study is the multiomics characterization of the regulatory landscape shaping human brain metastases. Thus, we believe further understanding of these key regulatory elements could lead to novel tumor targets with broad translational potential. Citation Format: Remi Klotz, Yiru Jess Wang, Alexis Zukowski, Frank Attenelo, Srinivas Ramachandran, Min Yu. Brain metastases roadmap reveals conserved regulatory dynamics rooted in dormant tumor cells [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr PR-006.