Pembrolizumab for patients with leptomeningeal metastasis from solid tumors: efficacy, safety, and cerebrospinal fluid biomarkers

Case report: Concurrent intrathecal and intravenous pembrolizumab for metastatic melanoma with leptomeningeal disease

Leptomeningeal disease (LMD) is a serious cancer complication associated with poor prognosis. Approximately 5%-25% of patients with melanoma develop LMD. Currently, no standard treatment protocol exists and very few cases have been reported. Despite ongoing advances in new therapies, treatment options for LMD remain limited. Herein, we report a case of intrathecal pembrolizumab administration in a patient with melanoma and LMD. Intrathecal pembrolizumab administration was feasible and safe at the doses tested. Drawing from this case, along with our expertise and the existing evidence on systemic immunotherapy, we propose that an immunotherapy approach involving intrathecal administration for patients with LMD from melanoma warrants additional exploration in clinical trials.

Proton Craniospinal Irradiation with Immunotherapy in Two Patients with Leptomeningeal Disease from Melanoma

Introduction

Proton craniospinal irradiation (pCSI) is a treatment option for leptomeningeal disease (LMD), which permits whole neuroaxis treatment while minimizing toxicity. Despite this, patients inevitably experience progression. Adding systemic therapy to pCSI may improve outcomes.

Methods

In this single-institution retrospective case series, we present the feasibility of treatment with pCSI (30Gy, 10 fractions) and an immune checkpoint inhibitor (ICI) in two sequential patients with LMD from melanoma.

Results

The first patient developed LMD related to BRAF V600E-mutant melanoma after prior ICI and BRAF-targeted therapy. After pCSI with concurrent nivolumab, the addition of relatlimab, and BRAF-targeted therapy, he remained alive 7 months after LMD diagnosis despite central nervous system progression. The second patient developed LMD related to BRAF-wildtype melanoma after up-front ICI. He received pCSI with concurrent ipilimumab and nivolumab, then nivolumab maintenance. Though therapy was held for ICI hepatitis, the patient remained progression-free 5 months after LMD diagnosis.

Conclusion

Adding an ICI to pCSI is feasible for patients with LMD and demonstrates a tolerable toxicity profile. While prospective evaluation is ultimately warranted, pCSI with ICI may confer survival benefits, even after prior ICI.

Pharmacotherapy for leptomeningeal disease in breast cancer

Clinical data supporting the best therapeutic approach in leptomeningeal disease (LMD; also known as leptomeningeal metastases or leptomeningeal carcinomatosis) are lacking. Despite the development of new agents and increasing incidence of central nervous system metastases, patients with LMD are often excluded from clinical trials in breast cancer, with very few conducted specifically in LMD. Consequently, current evidence may not provide an accurate reflection of real-world clinical practice. This review aims to provide further insight into the treatment strategies for patients with breast cancer and LMD. We explore differences between clinical and real-world studies, considering inclusion criteria, levels of evidence for LMD diagnosis, and time between diagnosis of LMD and LMD-specific treatment initiation. Patient prognosis is poor; median overall survival is limited to several months, with approximately 10% of patients alive at 12 months. Efficacy results have been reported for various systemic and intrathecal agents in LMD to date. Systemic therapies under investigation for LMD in breast cancer include tucatinib, trastuzumab deruxtecan, and paclitaxel trevatide; trastuzumab is the main intrathecal agent currently under investigation. Recent trials investigating systemic or intrathecal therapies are typically small, single-arm studies, and most are restricted to patients with human epidermal growth factor receptor 2-positive breast cancer. Moreover, the variability among inclusion criteria and response assessment tools makes the interpretation of results difficult. Large retrospective cohorts with various inclusion criteria and treatment regimens provide some real-world data. However, there remains an urgent need for randomised clinical trials which include patients with LMD across all breast cancer subtypes.

Harnessing immunotherapy for brain metastases: insights into tumor-brain microenvironment interactions and emerging treatment modalities

Brain metastases signify a deleterious milestone in the progression of several advanced cancers, predominantly originating from lung, breast and melanoma malignancies, with a median survival timeframe nearing six months. Existing therapeutic regimens yield suboptimal outcomes; however, burgeoning insights into the tumor microenvironment, particularly the immunosuppressive milieu engendered by tumor-brain interplay, posit immunotherapy as a promising avenue for ameliorating brain metastases. In this review, we meticulously delineate the research advancements concerning the microenvironment of brain metastases, striving to elucidate the panorama of their onset and evolution. We encapsulate three emergent immunotherapeutic strategies, namely immune checkpoint inhibition, chimeric antigen receptor (CAR) T cell transplantation and glial cell-targeted immunoenhancement. We underscore the imperative of aligning immunotherapy development with in-depth understanding of the tumor microenvironment and engendering innovative delivery platforms. Moreover, the integration with established or avant-garde physical methodologies and localized applications warrants consideration in the prevailing therapeutic schema.

Case report: Leptomeningeal metastasis of advanced nasopharyngeal carcinoma treated with chemoimmunotherapy

Leptomeningeal metastasis (LM) of nasopharyngeal carcinoma (NPC) is rare and associated with a poor prognosis. Immune checkpoint inhibitors (ICIs) have been the standard first-line treatment for metastatic NPC, but their effect on meningeal metastasis of NPC needs further investigation. A 38-year-old man complained of bilateral neck masses and sought medical care. He was diagnosed with nasopharyngeal undifferentiated non-keratinizing carcinoma with bilateral cervical lymph node metastasis and multiple bone metastasis, stage cT4N2M1 IVb. Then, the patient received first-line anti-PD-1 antibody tislelizumab combined with gemcitabine and cisplatin and achieved partial response. After seven cycles of first-line chemoimmunotherapy, the patient subsequently developed neurological symptoms, including unsteady walking, slurred speech, coughing on drinking, and unconsciousness. MRI showed leptomeningeal linear enhancement, and cerebrospinal fluid (CSF) analysis indicated Epstein-Barr virus (EBV) infection and squamous cell carcinoma cytology, suggesting the diagnosis of leptomeningeal metastasis. After the definite diagnosis of LM, the patient's condition deteriorated rapidly, leading to his death from brain herniation. We reported the first case of advanced NPC with pathologically confirmed leptomeningeal metastasis after receiving first-line chemoimmunotherapy. Considering the poor prognosis of LM, it is suggested to perform MRI and CSF examination when patients have neurological symptoms. Although immunotherapy significantly improved survival outcomes of advanced NPC patients, it seemed not effective in the setting of LM. The effect of other treatment options, such as radiation therapy and intrathecal therapy, requires further verification.

Cerebrospinal fluid immunological cytokines predict intracranial tumor response to immunotherapy in non-small cell lung cancer patients with brain metastases

Background

Immunotherapy has shown intracranial efficacy in non-small cell lung cancer (NSCLC) patients with brain metastases. However, predictive biomarkers for intracranial response to immunotherapy are lacking. This post-hoc analysis aimed to explore the potential of immunological cytokines in cerebrospinal fluid (CSF) to predict intracranial tumor response to immunotherapy in patients with brain metastases.

Methods

Treatment-naive NSCLC patients with brain metastases who received camrelizumab plus chemotherapy were enrolled. Paired plasma and CSF samples were prospectively collected at baseline and the first treatment assessment. All samples were analyzed for 92 immuno-oncology cytokines using Olink's panels.

Results

A total of 28 patients were included in this analysis. At baseline, most immunological cytokines were significantly lower in CSF than in plasma, whereas a subset comprising CD83, PTN, TNFRSF21, TWEAK, ICOSLG, DCN, IL-8, and MCP-1, was increased in CSF. Baseline CSF levels of LAMP3 were significantly higher in patients with intracranial tumor response, while the levels of CXCL10, IL-12, CXCL11, IL-18, TIE2, HGF, and PDCD1 were significantly lower. Furthermore, the CXCL10, CXCL11, TIE2, PDCD1, IL-18, HGF, and LAMP3 in CSF were also significantly associated with intracranial progression-free survival for immunotherapy. The identified cytokines in CSF were decreased at the first treatment evaluation in patients with intracranial tumor response. The logistic CSF immuno-cytokine model yielded an AUC of 0.91, as compared to PD-L1 expression (AUC of 0.72).

Conclusions

Immunological cytokines in CSF could predict intracranial tumor response to immunotherapy in NSCLC patients with brain metastases, and the findings warrant validation in a larger prospective cohort study.

Trial registration

ClinicalTrials.gov identifier: NCT04211090.

Novel approaches to treatment of leptomeningeal metastases

PURPOSE OF REVIEW

The incidence of leptomeningeal metastases is increasing in the setting of improved survival from systemic cancers. In more recent years, our understanding of leptomeningeal metastasis pathogenesis, how to diagnose and treat has been evolving.

RECENT FINDINGS

Diagnosing leptomeningeal metastasis has been challenging due to the limitations of cytology and neuroimaging; However, newer techniques detecting circulating tumor cells (CTCs) or circulating tumor DNA (ctDNA) have shown potential advantage with diagnosis, quantification and detection of oncogenic mutations. The use of small molecule inhibitors and immunotherapy has shown some promise in specific leptomeningeal metastasis subtypes.

SUMMARY

These new discoveries have improved clinical trials' ability to assess treatment response and thereby more optimally compare different treatments. Furthermore, they have helped the individual clinician better diagnose, monitor the disease and provide novel therapies.

New strategies for the treatment of breast cancer with leptomeningeal metastasis

PURPOSE OF REVIEW

Leptomeningeal metastasis is a complication of metastatic breast cancer that has a rising incidence likely due to the increased availability of novel systemic therapies, which have improved survival with better extracranial disease control but with limited intracranial efficacy. A poor prognosis of less than 6 months has historically been associated with leptomeningeal metastasis and it is often an exclusion factor for enrollment in clinical trials. There are limited evidence-based data supporting use of therapeutics in leptomeningeal metastasis patients and recommendations are largely derived from retrospective reports and small prospective studies. However, in recent years, there has been a surge in effective modern therapeutics with promising intracranial activity.

RECENT FINDINGS

The study aims to review the most recent updates in the management of leptomeningeal metastasis in breast cancer. We discuss the effectiveness and limitations of intrathecal administration, predictive biomarkers in the cerebrospinal fluid, proton radiation therapy and promising new systemic therapies such as antibody drug conjugates.

SUMMARY

Ongoing development of clinical trials that allow inclusion of leptomeningeal metastasis are essential for establishing efficacy potential and discovering new treatment options in this population of great unmet need.

Effects of intrathecal pemetrexed on the survival of patients with leptomeningeal metastasis from lung adenocarcinoma: a propensity score matching analysis

PURPOSE

To explore the impact of intrathecal pemetrexed (IP) on the survival of lung adenocarcinoma (LUAC) patients with leptomeningeal metastasis (LM).

METHODS

We analyzed patients with LUAC and LM who received systemic therapy after LM diagnosis at the Fujian Cancer Hospital between July 2018 and March 2022. Patients who underwent IP were assigned to the IP group; those without IP treatment were designated as the non-IP group. Propensity score matching (PSM) was performed between the two groups.

RESULTS

165 patients were enrolled: 83 and 82 in the IP and non-IP groups, respectively. After 1:1 PSM, we included 114 patients in the matched cohort. Median overall survival (OS) was 13.2 months (95% CI 10.8-15.6 months) in the IP group versus 10.1 months (95% CI 5.3-14.9 months) in the non-IP group (P = 0.488). Only Eastern Cooperative Oncology Group Performance Status (ECOG PS) was confirmed as an independent predictor for OS in the matched cohort (hazard ratio (HR) 2.03; P = 0.023). Multivariate competing-risks analysis showed that IP significantly correlated with central nervous system-related death (HR 0.31; P = 0.046). When stratified by ECOG PS, IP improved survival in patients with poor ECOG PS (PS = 2) (14.3 months vs. 1.6 months; P = 0.003).

CONCLUSIONS

Intrathecal pemetrexed did not enhance OS for the entire LUAC patient with LM compared to non-intrathecal chemotherapy. However, it exhibited the potential to reduce the risk of central nervous system-related mortality and improve survival in patients with poor ECOG PS.

Proton craniospinal irradiation with bevacizumab and pembrolizumab for leptomeningeal disease: a case report

Leptomeningeal disease (LMD) remains a challenging condition with a dismal prognosis. In this case study, we report partial response of LMD in a patient with metastatic large cell neuroendocrine carcinoma following treatment with proton craniospinal irradiation (CSI), bevacizumab, and pembrolizumab. Two years after the initial diagnosis, he presented with LMD. He underwent proton CSI with bevacizumab followed by combination therapy with pembrolizumab and bevacizumab. He had a partial disease response with progression-free survival after LMD diagnosis of 4.6 months. He unfortunately developed pembrolizumab induced hypophysitis, after which he experienced rapid neurologic clinical progression. Overall, this novel combination led to a durable partial response which warrants prospective evaluation.

Seq-ing the SINEs of central nervous system tumors in cerebrospinal fluid

It is often challenging to distinguish cancerous from non-cancerous lesions in the brain using conventional diagnostic approaches. We introduce an analytic technique called Real-CSF (repetitive element aneuploidy sequencing in CSF) to detect cancers of the central nervous system from evaluation of DNA in the cerebrospinal fluid (CSF). Short interspersed nuclear elements (SINEs) are PCR amplified with a single primer pair, and the PCR products are evaluated by next-generation sequencing. Real-CSF assesses genome-wide copy-number alterations as well as focal amplifications of selected oncogenes. Real-CSF was applied to 280 CSF samples and correctly identified 67% of 184 cancerous and 96% of 96 non-cancerous brain lesions. CSF analysis was considerably more sensitive than standard-of-care cytology and plasma cell-free DNA analysis in the same patients. Real-CSF therefore has the capacity to be used in combination with other clinical, radiologic, and laboratory-based data to inform the diagnosis and management of patients with suspected cancers of the brain.

Diagnostic and Therapeutic Updates in Leptomeningeal Disease

PURPOSE OF REVIEW

Leptomeningeal disease (LMD) is a devastating complication of advanced metastatic cancer associated with a poor prognosis and limited treatment options. This study reviews the current understanding of the clinical presentation, pathogenesis, diagnosis, and treatment of LMD. We highlight opportunities for advances in this disease.

RECENT FINDINGS

In recent years, the use of soluble CSF biomarkers has expanded, suggesting improved sensitivity over traditional cytology, identification of targetable mutations, and potential utility for monitoring disease burden. Recent studies of targeted small molecules and intrathecal based therapies have demonstrated an increase in overall and progression-free survival. In addition, there are several ongoing trials evaluating immunotherapy in LMD. Though overall prognosis of LMD remains poor, studies suggest a potential role for soluble CSF biomarkers in diagnosis and management and demonstrate promising findings in patient outcomes with targeted therapies for specific solid tumors. Despite these advances, there continues to be a gap of knowledge in this disease, emphasizing the importance of inclusion of LMD patients in clinical trials.

Immunotherapy: an emerging modality to checkmate brain metastasis

The diagnosis of brain metastasis (BrM) has historically been a dooming diagnosis that is nothing less than a death sentence, with few treatment options for palliation or prolonging life. Among the few treatment options available, brain radiotherapy (RT) and surgical resection have been the backbone of therapy. Within the past couple of years, immunotherapy (IT), alone and in combination with traditional treatments, has emerged as a reckoning force to combat the spread of BrM and shrink tumor burden. This review compiles recent reports describing the potential role of IT in the treatment of BrM in various cancers. It also examines the impact of the tumor microenvironment of BrM on regulating the spread of cancer and the role IT can play in mitigating that spread. Lastly, this review also focuses on the future of IT and new clinical trials pushing the boundaries of IT in BrM.

Leptomeningeal Metastases in Melanoma Patients: An Update on and Future Perspectives for Diagnosis and Treatment

Leptomeningeal disease (LMD) is a devastating complication of cancer with a particularly poor prognosis. Among solid tumours, malignant melanoma (MM) has one of the highest rates of metastasis to the leptomeninges, with approximately 10-15% of patients with advanced disease developing LMD. Tumour cells that metastasise to the brain have unique properties that allow them to cross the blood-brain barrier, evade the immune system, and survive in the brain microenvironment. Metastatic colonisation is achieved through dynamic communication between metastatic cells and the tumour microenvironment, resulting in a tumour-permissive milieu. Despite advances in treatment options, the incidence of LMD appears to be increasing and current treatment modalities have a limited impact on survival. This review provides an overview of the biology of LMD, diagnosis and current treatment approaches for MM patients with LMD, and an overview of ongoing clinical trials. Despite the still limited efficacy of current therapies, there is hope that emerging treatments will improve the outcomes for patients with LMD.

Leptomeningeal Metastasis: A Review of the Pathophysiology, Diagnostic Methodology, and Therapeutic Landscape

The present review aimed to establish an understanding of the pathophysiology of leptomeningeal disease as it relates to late-stage development among different cancer types. For our purposes, the focused metastatic malignancies include breast cancer, lung cancer, melanoma, primary central nervous system tumors, and hematologic cancers (lymphoma, leukemia, and multiple myeloma). Of note, our discussion was limited to cancer-specific leptomeningeal metastases secondary to the aforementioned primary cancers. LMD mechanisms secondary to non-cancerous pathologies, such as infection or inflammation of the leptomeningeal layer, were excluded from our scope of review. Furthermore, we intended to characterize general leptomeningeal disease, including the specific anatomical infiltration process/area, CSF dissemination, manifesting clinical symptoms in patients afflicted with the disease, detection mechanisms, imaging modalities, and treatment therapies (both preclinical and clinical). Of these parameters, leptomeningeal disease across different primary cancers shares several features. Pathophysiology regarding the development of CNS involvement within the mentioned cancer subtypes is similar in nature and progression of disease. Consequently, detection of leptomeningeal disease, regardless of cancer type, employs several of the same techniques. Cerebrospinal fluid analysis in combination with varied imaging (CT, MRI, and PET-CT) has been noted in the current literature as the gold standard in the diagnosis of leptomeningeal metastasis. Treatment options for the disease are both varied and currently in development, given the rarity of these cases. Our review details the differences in leptomeningeal disease as they pertain through the lens of several different cancer subtypes in an effort to highlight the current state of targeted therapy, the potential shortcomings in treatment, and the direction of preclinical and clinical treatments in the future. As there is a lack of comprehensive reviews that seek to characterize leptomeningeal metastasis from various solid and hematologic cancers altogether, the authors intended to highlight not only the overlapping mechanisms but also the distinct patterning of disease detection and progression as a means to uniquely treat each metastasis type. The scarcity of LMD cases poses a barrier to more robust evaluations of this pathology. However, as treatments for primary cancers have improved over time, so has the incidence of LMD. The increase in diagnosed cases only represents a small fraction of LMD-afflicted patients. More often than not, LMD is determined upon autopsy. The motivation behind this review stems from the increased capacity to study LMD in spite of scarcity or poor patient prognosis. In vitro analysis of leptomeningeal cancer cells has allowed researchers to approach this disease at the level of cancer subtypes and markers. We ultimately hope to facilitate the clinical translation of LMD research through our discourse.

High-dimensional immune cell profiling of cerebrospinal fluid from patients with metastatic breast cancer and leptomeningeal disease

Leptomeningeal disease (LMD) is a devastating complication of metastatic breast cancer (MBC). In this non-therapeutic study, we enrolled 12 patients with MBC and known or suspected LMD who were undergoing a lumbar puncture as part of clinical care and collected extra cerebrospinal fluid (CSF) and a paired blood sample from each patient at a single time point. Of the 12 patients, 7 patients are confirmed to have LMD based on positive cytology and/or convincing MRI imaging (LMD^pos), and 5 patients are deemed not to have LMD based on similar criteria (LMD^neg). Using high-dimensional, multiplexed flow cytometry, we profile and compare the CSF and peripheral blood mononuclear cell (PBMCs) immune populations between patients with LMD and those without. Patients with LMD observe a lower overall frequency of CD45⁺ cells (29.51% vs. 51.12%, p < 0.05), lower frequencies of CD8⁺ T cells (12.03% vs. 30.40%, p < 0.01), and higher frequency of T_regs than patients without LMD. Interestingly, the frequency of partially exhausted CD8⁺ T cells (CD38^hiTIM3^lo) is ~6.5-fold higher among patients with LMD vs. those without (2.99% vs. 0.44%, p < 0.05). Taken together, these data suggest that patients with LMD may have lower overall immune infiltrates than patients without LMD, suggesting a more permissive CSF immune microenvironment but a higher frequency of partially exhausted CD8⁺ T cells, which may offer an important therapeutic target.

Concurrent intrathecal and intravenous nivolumab in leptomeningeal disease: phase 1 trial interim results

There is a critical need for effective treatments for leptomeningeal disease (LMD). Here, we report the interim analysis results of an ongoing single-arm, first-in-human phase 1/1b study of concurrent intrathecal (IT) and intravenous (IV) nivolumab in patients with melanoma and LMD. The primary endpoints are determination of safety and the recommended IT nivolumab dose. The secondary endpoint is overall survival (OS). Patients are treated with IT nivolumab alone in cycle 1 and IV nivolumab is included in subsequent cycles. We treated 25 patients with metastatic melanoma using 5, 10, 20 and 50 mg of IT nivolumab. There were no dose-limiting toxicities at any dose level. The recommended IT dose of nivolumab is 50 mg (with IV nivolumab 240 mg) every 2 weeks. Median OS was 4.9 months, with 44% and 26% OS rates at 26 and 52 weeks, respectively. These initial results suggest that concurrent IT and IV nivolumab is safe and feasible with potential efficacy in patients with melanoma LMD, including in patients who had previously received anti-PD1 therapy. Accrual to the study continues, including in patients with lung cancer. ClinicalTrials.gov registration: NCT03025256 .

Leptomeningeal anti-tumor immunity follows unique signaling principles

Metastasis to the cerebrospinal fluid (CSF)-filled leptomeninges, or leptomeningeal metastasis (LM), represents a fatal complication of cancer. Proteomic and transcriptomic analyses of human CSF reveal a substantial inflammatory infiltrate in LM. We find the solute and immune composition of CSF in the setting of LM changes dramatically, with notable enrichment in IFN-γ signaling. To investigate the mechanistic relationships between immune cell signaling and cancer cells within the leptomeninges, we developed syngeneic lung, breast, and melanoma LM mouse models. Here we show that transgenic host mice, lacking IFN-γ or its receptor, fail to control LM growth. Overexpression of Ifng through a targeted AAV system controls cancer cell growth independent of adaptive immunity. Instead, leptomeningeal IFN-γ actively recruits and activates peripheral myeloid cells, generating a diverse spectrum of dendritic cell subsets. These migratory, CCR7+ dendritic cells orchestrate the influx, proliferation, and cytotoxic action of natural killer cells to control cancer cell growth in the leptomeninges. This work uncovers leptomeningeal-specific IFN-γ signaling and suggests a novel immune-therapeutic approach against tumors within this space.

Advances in the Management of Central Nervous System Metastases in Non-Small Cell Lung Cancer

Central nervous system (CNS) metastases are common among patients with non-small cell lung cancer (NSCLC). While the presence of brain metastases has historically portended poor prognosis, recent advances in local and systemic therapies have greatly improved outcomes for NSCLC patients with CNS involvement. Stereotactic radiology surgery (SRS) has emerged as an effective radiotherapy technique with fewer toxicities compared to whole brain radiotherapy (WBRT). Furthermore, multi-generation tyrosine kinase inhibitors (TKIs) with CNS overall response rates (ORR) of up to 70-80% are now an accepted first-line approach for a subset of advanced NSCLC patients with targetable molecular alterations. In addition, while the CNS was once considered an immunologic sanctuary site, growing evidence shows that immune checkpoint inhibitors (ICIs) can induce durable responses in brain metastases as well. Ongoing efforts to optimize CNS metastases management are necessary to refine multimodal treatment approaches and develop new therapeutics with better CNS penetrance.

The Evolving Landscape of Leptomeningeal Cancer from Solid Tumors: A Systematic Review of Clinical Trials

Leptomeningeal carcinomatosis (LMC) is a fatal but uncommon complication occurring in 5-15% of patients with stage IV cancer. Current treatment options are ineffective at managing leptomeningeal spread, with a median overall survival (mOS) of 2-6 months. We aimed to conduct a systematic review of the literature to identify past and future therapies for LMC from solid tumors. Forty-three clinical trials (CTs) published between 1982-2022 were identified. Of these, 35 (81.4%) were non-randomized CTs and 8 (18.6%) were randomized CTs. The majority consisted of phase I (16.3%) and phase II CTs (65.1%). Trials enrolled patients with LMC from various primary histology (n = 23, 57.5%), with one CT evaluating LCM from melanoma (2.4%). A total of 21 trials evaluated a single modality treatment. Among CTs, 23.7% closed due to low accrual. Intraventricular (ITV)/intrathecal (IT) drug delivery was the most common route of administration (n = 22, 51.2%) vs. systemic drug delivery (n = 13, 30.3%). Two clinical trials evaluated the use of craniospinal irradiation for LMC with favorable results. LMC continues to carry a dismal prognosis, and over the years, increments in survival have remained stagnant. A paradigm shift towards targeted systemic therapy with continued standardization of efficacy endpoints will help to shed light on promising treatments.

Leptomeningeal Metastasis from Non-Small Cell Lung Cancer and Current Landscape of Treatments

Leptomeningeal metastasis (LM), also known as leptomeningeal carcinomatosis (LC), is a devastating complication of metastatic cancer that occurs when neoplastic cells invade the meningeal space. Diagnosis of LM remains challenging given the heterogeneous signs and symptoms at presentation and requires thorough neurological examination, cerebrospinal fluid (CSF) analysis, and MRI of the brain and spine with gadolinium. Detecting neoplastic cells in the CSF is the gold standard for diagnosing leptomeningeal metastases; however, it has low sensitivity and may require multiple CSF samples. New emerging technologies, such as liquid biopsy of CSF, have increased sensitivity and specificity for detecting circulating tumor cells in CSF. The management of LM in patients with NSCLC requires an individualized multidisciplinary approach. Treatment options include surgery for ventricular shunt placement, radiation therapy to bulky or symptomatic disease sites, systemic or intrathecal chemotherapy, molecularly targeted agents, and, more recently, immunotherapy. Targeting actionable mutations in LM from NSCLC, such as EGFR tyrosine kinase inhibitors or anaplastic lymphoma kinase gene rearrangement inhibitors, has shown encouraging results in terms of disease control and survival. Although there are limited data regarding the use of immunotherapy in LM, immunotherapy has produced promising results in several case reports. In this review, we focused on the epidemiology, pathophysiology, clinical presentation, diagnosis, and current treatment strategies, with a special emphasis on novel agents, including targeted therapies and immunotherapy of LM in patients with NSCLC.

Role of Systemic Immunoinflammation Landscape in the Overall Survival of Patients with Leptomeningeal Metastases from Lung Cancer

Purpose

Several biomarkers, such as baseline neutrophil-to-lymphocyte ratio (NLR), have been more investigated in patients with brain metastases (BM), while their role in patients with leptomeningeal metastases (LM) has not been clarified. Considering the difference between the clinical behaviour of BM and LM, there is the need for addressing the role of these biomarkers in LM.

Methods

The present study retrospectively analyzed 95 consecutive patients with LM from lung cancer who were diagnosed at the National Cancer Center, Cancer Hospital of Chinese Academy of Medical Sciences between January 2016 and December 2019. Baseline NLR, platelet-to-lymphocyte ratio (PLR), systemic immunoinflammation index (SII), and lymphocyte-to-monocyte ratio at diagnosis of LM were calculated based on complete blood count and correlated, along with other characteristics, with overall survival (OS) using univariate and multivariate analyses. The best cutoff values for systemic immunoinflammation biomarkers were derived using the surv_cutpoint function in R software, which optimized the significance of the split between Kaplan-Meier survival curves.

Results

Median OS of patients with LM was 12 months (95% CI 9-17 months). On univariate analysis, NLR, PLR, SII, LMR, sex, smoking history, ECOG performance status (PS) scores, histological subtypes and targeted therapy were all significantly associated with OS. Only NLR (P=0.034, 95% CI 1.060-4.578) and ECOG PS scores (P=0.019, 95% CI 0.137-0.839) maintained a significant association with OS on multivariate analysis. Furthermore, patients with baseline NLR >3.57 had significantly worse OS than patients with NLR ≤3.57 (median OS 7 vs 17 months), as did patients with ECOG PS scores >2 vs ≤2 (median OS 4 vs 15 months).

Conclusion

Both baseline NLR and PS scores at the time of LM diagnosis are helpful and available prognostic biomarkers for patients with LM from lung cancer.

Leptomeningeal metastases in non-small cell lung cancer: Diagnosis and treatment

Leptomeningeal metastasis (LM) is a rare complication of non-small cell lung cancer (NSCLC) with highly mortality. LM will occur once tumor cells spread to the cerebrospinal fluid (CSF) space. Patients may suffer blindness, paralysis, and mental disorders that seriously affect their quality of life. There is a clear unmet need to improve the efficacy of diagnosis and treatment of LM. To better solve this problem, it is helpful to clarify the potential mechanisms of LM. Clinical manifestations, magnetic resonance imaging, and CSF biopsy are the key components in the diagnosis of NSCLC with LM. CSF cytology is insufficient and should be combined with liquid biology. The application of radiotherapy, intrathecal treatment, targeted therapy and immunotherapy provides more options for LM patients. Each treatment has a particular level of efficacy and can be used alone or in combination for individual patients. New technologies in radiotherapy, drug repositioning in intrathecal treatment, and the higher CSF permeability in TKIs have brought new breakthroughs in the treatment of LM. This review focused on clarifying the potential mechanisms, discussing the major clinical challenges, and summarizing recent advances in the diagnosis and treatment of LM from NSCLC. Future research is essential to improve the efficiency of diagnosis, to optimize therapy and to enhance patient prognosis.

Leptomeningeal Metastases: New Opportunities in the Modern Era

Leptomeningeal metastases arise from cancer cell entry into the subarachnoid space, inflicting significant neurologic morbidity and mortality across a wide range of malignancies. The modern era of cancer therapeutics has seen an explosion of molecular-targeting agents and immune-mediated strategies for patients with breast, lung, and melanoma malignancies, with meaningful extracranial disease control and improvement in patient survival. However, the clinical efficacy of these agents in those with leptomeningeal metastases remains understudied, due to the relative rarity of this patient population, the investigational challenges associated with studying this dynamic disease state, and brisk disease pace. Nevertheless, retrospective studies, post hoc analyses, and small prospective trials in the last two decades provide a glimmer of hope for patients with leptomeningeal metastases, suggesting that several cancer-directed strategies are not only active in the intrathecal space but also improve survival against historical odds. The continued development of clinical trials devoted to patients with leptomeningeal metastases is critical to establish robust efficacy outcomes in this patient population, define drug pharmacokinetics in the intrathecal space, and uncover new avenues for treatment in the face of leptomeningeal therapeutic resistance.

Genotyping of cerebrospinal fluid in lung cancer patients with leptomeningeal metastasis

Background

The prognosis of non–small‐cell lung cancer (NSCLC) with leptomeningeal metastasis (LM) is poor. Detection of cell‐free DNA (cfDNA) by next generation sequencing (NGS) in cerebrospinal fluid (CSF) may facilitate diagnosis of LM and identification of drug resistance mechanisms, yet its clinical use needs to be further verified.

Methods

We performed a retrospective cohort study to assess the genetic profiles of paired CSF and plasma samples in lung cancer patients with LM. Of 17 patients screened, a total of 14 patients with LM and paired NGS tests were enrolled.

Results

All patients harbor driver gene mutations, including 12 epidermal growth factor receptor (EGFR) activating mutations, 1 anaplastic lymphoma kinase (ALK) rearrangement, and 1 ROS‐1 fusion. Genetic mutations were detected in CSF cfDNA from 92.9% patients (13/14), which was significantly higher than that from the plasma (9/14, 64.2%). The mutations were highly divergent between CSF and plasma cfDNA, with a concordance rate of 24.38% and 10 mutations shared by the two media. CSF cfDNA could also benefit the analysis of resistance mechanisms to targeted therapies. In five patients who experienced progression on 1st or 2nd generation EGFR‐tyrosine kinase inhibitors (TKIs), RB1 mutation, and amplification of MET and EGFR were detected in CSF cfDNA only. In eight patients with LM progression on osimertinib resistance, EGFR amplification was detected in CSF cfDNA from four patients, whereas no CNVs were detected in the matched plasma samples.

Conclusions

In conclusion, CSF could be superior to plasma in providing a more comprehensive genetic landscape of LM to find out drug resistance mechanisms and guide subsequent treatments.

Development of Two Diagnostic Prediction Models for Leptomeningeal Metastasis in Patients With Solid Tumors

Objectives

For accurate diagnosis of leptomeningeal metastasis (LM) and to avoid unnecessary examinations or lumber puncture (LP), we develop two diagnostic prediction models for patients with solid tumors.

Study Design, Setting, and Participants

This is a retrospective cohort study launched at the Second Affiliated Hospital of Dalian Medical University. In total, 206 patients who had been admitted between January 2005 and December 2021 with a solid tumor and clinical suspicion of LM were enrolled to develop model A. In total, 152 patients of them who underwent LPs for cytology and biochemistry were enrolled to develop model B.

Model Development

Diagnostic factors included skull metastasis, active brain metastasis, progressed extracranial disease, number of extracranial organs involved, number of symptoms, cerebrospinal fluid (CSF) protein, and CSF glucose. The outcome predictor was defined as the clinical diagnosis of LM. Logistic least absolute shrinkage and selection operator (LASSO) regression was used to identify relevant variables and fit the prediction model. A calibration curve and the concordance index (c-index) were used to evaluate calibration and discrimination ability. The n-fold cross-validation method was used to internally validate the models. The decision curve analysis (DCA) and the interventions avoided analysis (IAA) were used to evaluate the clinical application.

Results

The area under the curve (AUC) values of models A and B were 0.812 (95% CI: 0.751–0.874) and 0.901 (95% CI: 0.852–0.949). Respectively, compared to the first magnetic resonance imaging (MRI) and first LP, models A and B showed a higher AUC (model A vs. first MRI: 0.812 vs. 0.743, p = 0.087; model B vs. first LP: 0.901 vs. 0.800, p = 0.010). The validated c-indexes were 0.810 (95% CI: 0.670–0.952) and 0.899 (95% CI: 0.823–0.977). The calibration curves show a good calibrated ability. The evaluation of clinical application revealed a net clinical benefit and a reduction of unnecessary interventions using the models.

Conclusions

The models can help improve diagnostic accuracy when used alone or in combination with conventional work-up. They also exhibit a net clinical benefit in medical decisions and in avoiding unnecessary interventions for patients with LM. Studies focused on external validation of our models are necessary in the future.

Immunotherapy in NSCLC Patients With Brain and Leptomeningeal Metastases

Immunotherapy has now been integrated as a treatment strategy for most patients with non-small cell lung cancer (NSCLC). However, the pivotal clinical trials that demonstrated its impressive efficacy often did not include patients with active, untreated brain metastases or leptomeningeal carcinomatosis. Nevertheless, NSCLC is the most common tumor to metastasize to the brain, and patients develop brain and meningeal involvement in approximately 40 and 10% of cases, respectively. Consequently, the appropriate care of these patients is a recurrent clinical concern. Although there are many aspects that would merit further investigation to explain the mechanism of intracranial response to immune checkpoint inhibitors (ICPs), some data suggest that they are able to cross the blood–brain barrier, resulting in local tumor microenvironment modification. This results in a similar clinical benefit in patients with stable, previously treated brain metastases compared to the general population. Despite important limitations, some real-life studies have described that the ICPs’ efficacy was maintained also in less selected patients with untreated or symptomatic brain metastases. In contrast, few data are available about patients with leptomeningeal carcinomatosis. Nevertheless, neurological complications due to ICP treatment in patients with brain metastases have to be evaluated and carefully monitored. Despite the fact that limited data are available in the literature, the purpose of this review is to show that the multimodal treatment of these patients with brain metastases and/or leptomeningeal disease should be discussed during tracing of the history of the disease, participating in the local and possibly systemic control of NSCLC.

TGF-β Signaling Pathway-Based Model to Predict the Subtype and Prognosis of Head and Neck Squamous Cell Carcinoma

Background: Although immunotherapy with immune checkpoint therapy has been used to treat head and neck squamous cell carcinoma (HNSCC), response rates and treatment sensitivity remain limited. Recent studies have indicated that transforming growth factor-β (TGF-β) may be an important target for novel cancer immunotherapies.

Materials and methods: We collected genomic profile data from The Cancer Genome Atlas and Gene Expression Omnibus. The least absolute shrinkage and selection operator method and Cox regression were used to establish a prognostic model. Gene set enrichment analysis was applied to explore biological functions. Tracking of indels by decomposition and subclass mapping algorithms were adopted to evaluate immunotherapy efficiency.

Result: We established a seven TGF-β pathway-associated gene signature with good prediction efficiency. The high-risk score subgroup mainly showed enrichment in tumor-associated signaling such as hypoxia and epithelial-mesenchymal transition (EMT) pathways; This subgroup was also associated with tumor progression. The low-risk score subgroup was more sensitive to immunotherapy and the high-risk score subgroup to cisplatin, erlotinib, paclitaxel, and crizotinib.

Conclusion: The TGF-β pathway signature gene model provides a novel perspective for evaluating effectiveness pre-immunotherapy and may guide further studies of precision immuno-oncology.

Challenges and Advances in Diagnosis and Treatment of Leptomeningeal Disease (LMD)

Leptomeningeal disease (LMD) is a devastating category of CNS metastasis with a very poor prognosis and limited treatment options. With maximal aggressive therapy, survival times remain short and, without treatment, prognosis is measured in weeks. Both LMD diagnosis and treatment are challenging topics within neuro-oncology. In this review, we discuss the advances in LMD diagnosis with a focus on the role of circulating tumor DNA (ctDNA) and discuss the role of targeted and immunotherapy in LMD treatment.

Leptomeningeal disease and brain control after postoperative stereotactic radiosurgery with or without immunotherapy for resected brain metastases

Purpose

Immunotherapy has shown activity in patients with brain metastases (BM) and leptomeningeal disease (LMD). We have evaluated LMD and intraparenchymal control rates for patients with resected BM receiving postoperative stereotactic radiosurgery (SRS) and immunotherapy or postoperative SRS alone. We hypothesize that postoperative SRS and immunotherapy will result in a lower rate of LMD with acceptable toxicity compared with postoperative SRS.

Patients and methods

One hundred and twenty-nine patients with non-small-cell lung cancer (NSCLC) and melanoma BM who received postoperative fractionated SRS (fSRS; 3×9 Gy) in combination with immunotherapy or postoperative fSRS alone for completely resected BM were retrospectively evaluated. The primary endpoint of the study was the rate of LMD after treatments. The secondary endpoints were local failure, distant brain parenchymal failure (DBF), overall survival (OS), and treatment-related toxicity.

Results

Sixty-three patients received postoperative SRS and immunotherapy, either nivolumab or pembrolizumab, and 66 patients received postoperative SRS alone to the resection cavity. With a median follow-up of 15 months, LMD occurred in 19 patients: fSRS group, 14; fSRS and immunotherapy, 5. The 12-month LMD cumulative rates were 22% (95% CI 14% to 37%) in the fSRS group and 6% (95% CI 2% to 17%) in the combined treatment group (p=0.007). Resection cavity control was similar between the groups, whereas DBF and OS were significantly different; the 1-year DBF rates were 31% (95% CI 20% to 46%) in the fSRS and immunotherapy group and 52% (95% CI 39% to 68%) in the fSRS group; respective OS rates were 78% (95% CI 67% to 88%) and 58.7% (95% CI 47% to 70%). Twenty-two patients undergoing postoperative fSRS and immunotherapy and nine subjected to postoperative fSRS experienced treatment-related imaging changes suggestive of radiation-induced brain necrosis (p=0.02).

Conclusions

Postoperative fSRS in combination with immunotherapy decreases the incidence of LMD and DBF in patients with resected BM from NSCLC and melanoma as compared with fSRS alone, reducing the rate of neurological death and prolonging survival.