Inflammatory CNS disease caused by immune checkpoint inhibitors: status and perspectives

Paraneoplastic Neurologic Disorders

OBJECTIVE

This article reviews the clinical presentations, neural antibody associations, and oncologic accompaniments of paraneoplastic neurologic syndromes and neurologic autoimmunity in the context of immune checkpoint inhibitor (ICI) cancer immunotherapy.

LATEST DEVELOPMENTS

Neural antibody discovery has improved the diagnosis of paraneoplastic neurologic syndromes. Neural antibodies also delineate the underlying disease pathophysiology and thus inform outcomes and treatments. Neural antibodies specific for extracellular proteins have pathogenic potential, whereas antibodies specific for intracellular targets are biomarkers of a cytotoxic T-cell immune response. A recent update in paraneoplastic neurologic syndrome criteria suggests high- and intermediate-risk phenotypes as well as neural antibodies to improve diagnostic accuracy in patients with paraneoplastic neurologic syndromes; a score was created based on this categorization. The introduction of ICI cancer immunotherapy has led to an increase in cancer-related neurologic autoimmunity with distinct clinical phenotypes.

ESSENTIAL POINTS

Paraneoplastic neurologic syndromes reflect an ongoing immunologic response to cancer mediated by effector T cells or antibodies. Paraneoplastic neurologic syndromes can present with manifestations at any level of the neuraxis, and neural antibodies aid diagnosis, focus cancer screening, and inform prognosis and therapy. In patients with high clinical suspicion of a paraneoplastic neurologic syndrome, cancer screening and treatment should be undertaken, regardless of the presence of a neural antibody. ICI therapy has led to immune-mediated neurologic complications. Recognition and treatment lead to improved outcomes.

Cerebral 18F-FDG PET/CT Metabolism as Diagnostic Signature for Central Nervous System Toxicity After Immune Checkpoint Blockade Cancer Treatment

Our aim was to investigate probable biomarkers specific to immune-related central nervous system toxicity (CNST) in cancer patients treated with immune checkpoint inhibitors (ICI) by analysis of 18F-FDG PET/CT images. Methods: Cancer patients receiving ICI treatment were enrolled in a multicenter observational study that analyzed regional metabolic changes before and during CNST onset from January 2020 to February 2022. In 1:1 propensity score-matched pairs, the regional SUVmean of each bilateral brain lobe of CNST patients (CNST+) was compared with that of patients who had central nervous system infections (CNSIs) and patients without CNST or CNSI (CNST-). In a validation cohort, patients were recruited from February 2022 to July 2023 and followed up for 24 wk after the start of ICI. Early changes in regional SUVmean at 5-6 wk after therapy initiation were evaluated for ability to predict later CNST onset. Results: Of 6,395 ICI-treated patients, 2,387 underwent prognostic 18F-FDG PET/CT and 125 of the scanned patients had CNST (median time from ICI treatment to onset, 9 wk; quartile range, 2-23 wk). Regional 18F-FDG PET/CT SUVmean changes were higher in CNST+ than in CNST- patients (117 patient pairs) but were lower than in CNSI patients (50 pairs). Differentiating analysis reached an area under the curve (AUC) of 0.83 (95% CI, 0.78-0.88) for CNST+ versus CNST- and of 0.80 (95% CI, 0.72-0.89) for CNST+ versus CNSI. Changes in SUVmean were also higher before CNST onset than for CNST- (60 pairs; AUC, 0.74; 95% CI, 0.66-0.83). In a validation cohort of 2,878 patients, preonset changes in SUVmean reached an AUC of 0.86 (95% CI, 0.79-0.94) in predicting later CNST incidence. Conclusion: Brain regional hypermetabolism could be detected during and before CNST clinical onset. CNST may be a distinct pathologic entity versus brain infections defined by 18F-FDG PET/CT brain scans. Regional SUV differences may be translated into early diagnostic tools based on moderate differentiating accuracy in our study.

Neurological Immune-Related Adverse Events Induced by Immune Checkpoint Inhibitors

The use of immune checkpoint inhibitors (ICIs) for the treatment of various advanced and aggressive types of malignancy has significantly increased both survival and long-term remission rates. ICIs block crucial inhibitory pathways of the immune system, in order to trigger an aggravated immune response against the tumor. However, this enhanced immune activation leads to the development of numerous immune-related adverse events (irAEs), which may affect any system. Although severe neurological irAEs are relatively rare, they carry a high disability burden, and they can be potentially life-threatening. Therefore, clinicians must be alert and act promptly when individuals receiving ICIs present with new-onset neurological symptoms. In this narrative review, we have collected all the currently available data regarding the epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of post-ICI neurological irAEs. This review aims to raise physicians' awareness, enrich their knowledge regarding disease pathogenesis, and guide them through the diagnosis and management of post-ICI neurological irAEs.

Cancer and multiple sclerosis: 2023 recommendations from the French Multiple Sclerosis Society

BACKGROUND

Epidemiological data reveal that 45% of persons with multiple sclerosis (PwMS) in France are more than 50 years. This population more than 50 is more susceptible to cancer, and this risk may be increased by frequent use of immunosuppressive drugs. Consequently, concerns have arisen about the potential increased risk of cancer in PwMS and how patients should be screened and managed in terms of cancer risk.

OBJECTIVE

To develop evidence-based recommendations to manage the coexistence of cancer and multiple sclerosis (MS).

METHODS

The French Group for Recommendations in MS collected articles from PubMed and university databases covering the period January 1975 through June 2022. The RAND/UCLA method was employed to achieve formal consensus. MS experts comprehensively reviewed the full-text articles and developed the initial recommendations. A group of multidisciplinary health care specialists then validated the final proposal.

RESULTS

Five key questions were addressed, encompassing various topics such as cancer screening before or after initiating a disease-modifying therapy (DMT), appropriate management of MS in the context of cancer, recommended follow-up for cancer in patients receiving a DMT, and the potential reintroduction of a DMT after initial cancer treatment. A strong consensus was reached for all 31 recommendations.

CONCLUSION

These recommendations propose a strategic approach to managing cancer risk in PwMS.

A Case of Anti-Ma2 Encephalitis Presenting with Pendular Torsional Nystagmus

Antibodies against the neuronal protein Ma2 have been reported in a peculiar form of paraneoplastic encephalitis with prominent involvement of the limbic, brainstem, and diencephalic structures and usually associated with germ cell testicular, lung, or breast cancer. The diagnosis is frequently challenged by atypical clinical manifestations including parkinsonism, sleep disturbances, hypothalamic-pituitary dysfunctions, and motor neuron-like syndrome. In recent years, the advent of monoclonal antibodies targeting immune checkpoints has deeply changed the treatment of different tumors, especially melanoma and lung cancer. However, given their nature, an increasing number of neurological immune-related adverse events, including ocular motor abnormalities, have been described. Here, we report a woman with advanced non-small cell lung cancer treated with anti-PD-L1 durvalumab, presenting with an isolated pendular torsional nystagmus, in association with anti-Ma2 antibodies. This peculiar case widens our knowledge on the clinical presentation of anti-Ma2 encephalitis associated with checkpoint inhibitors.

Lung Cancer Wherein Durvalumab Induced Both Anti-CRMP-5 Antibody-related Paraneoplastic Neurological Syndromes and Neurological Adverse Events

A 68-year-old man with small-cell lung cancer developed anti-collapsin response-mediator protein (CRMP)-5 antibody-related paraneoplastic neurological syndrome (PNS) presenting with ataxia and chorea during treatment with durvalumab. As a result of steroid therapy, anti-CRMP-5 antibodies became negative, hyperintense lesions on brain magnetic resonance imaging disappeared, and neurological symptoms improved. After resuming durvalumab, he became unable to walk due to neurological adverse events (nAEs). There have been no reported cases manifesting PNSs and nAEs as a result of the same immune checkpoint inhibitors (ICIs) administered at different times. Resuming ICIs in patients diagnosed with PNSs should be performed with prudence.

Synergistic effects of immune checkpoints and checkpoint inhibitors in inflammatory neuropathies: Implications and mechanisms

Immune checkpoint molecules play pivotal roles in the regulation of immune homeostasis. Disruption of the immune checkpoints causes autoimmune/inflammatory as well as malignant disorders. Over the past few years, the immune checkpoint molecules with inhibitory function emerged as potential therapeutic targets in oncological conditions. The inhibition of the function of these molecules by using immune checkpoint inhibitors (ICIs) has brought paradigmatic changes in cancer therapy due to their remarkable clinical benefits, not only in improving the quality of life but also in prolonging the survival time of cancer patients. Unfortunately, the ICIs soon turned out to be a "double-edged sword" as the use of ICIs caused multiple immune-related adverse effects (irAEs). The development of inflammatory neuropathies such as Guillain-Barré syndrome (GBS) and Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) as the secondary effects of immunotherapy appeared very challenging as these conditions result in significant and often permanent disability. The underlying mechanism(s) through which ICIs trigger inflammatory neuropathies are currently not known. Compelling evidence suggests autoimmune reaction and/or inflammation as the independent risk mechanism of inflammatory neuropathies. There is a lack of understanding as to whether prior exposure to the risk factors of inflammatory neuropathies, the presence of germline genetic variants in immune function-related genes, genetic variations within immune checkpoint molecules, the existence of autoantibodies, and activated/memory T cells act as determining factors for ICI-induced inflammatory neuropathies. Herein, we highlight the available pieces of evidence, discuss the mechanistic basis, and propose a few testable hypotheses on inflammatory neuropathies as irAEs of immunotherapy.

Impact of Immune Checkpoint Inhibitors on the Course of Multiple Sclerosis

OBJECTIVES

Immune checkpoint inhibitors (ICIs) are increasingly used in cancer treatment. Their mechanism of action raises the question of possible exacerbation of preexisting multiple sclerosis (MS). The aim of our study was to assess the risk of increased MS activity, defined by the occurrence of a relapse and/or a new MRI lesion, after ICI initiation.

METHODS

This French multicentric study collected retrospective and prospective data on patients with MS treated with ICIs after a cancer diagnosis.

RESULTS

We identified 18 patients with a median age of 48 years. Three of them (17%), all aged 50 years or younger, with a relapsing-remitting course, showed clinical and/or radiologic signs of MS activity 3 to 6 months after ICI initiation. They had stopped disease-modifying treatment (DMT) several months earlier, at the time of cancer diagnosis. Only one had both clinical and MRI activity, with mild severity and complete recovery.

DISCUSSION

Our study suggests that the overall risk of MS activity under ICI is low and could be mainly driven by DMT discontinuation, as in MS in general. Although larger studies are needed for better risk assessment in younger patients with more active disease, ICI should be considered when needed in patients with MS.

Neurological adverse events of immune checkpoint inhibitors and the development of paraneoplastic neurological syndromes

Immune checkpoint inhibitors, a class of oncological treatments that enhance antitumour immunity, can trigger neurological adverse events closely resembling paraneoplastic neurological syndromes. Unlike other neurological adverse events caused by these drugs, post-immune checkpoint inhibitor paraneoplastic neurological syndromes predominantly affect the CNS and are associated with neural antibodies and cancer types commonly found also in spontaneous paraneoplastic neurological syndromes. Furthermore, post-immune checkpoint inhibitor paraneoplastic neurological syndromes have poorer neurological outcomes than other neurological adverse events of immune checkpoint inhibitors. Early diagnosis and initiation of immunosuppressive therapy are likely to be crucial in preventing the accumulation of neurological disability. Importantly, the neural antibodies found in patients with post-immune checkpoint inhibitor paraneoplastic neurological syndromes are sometimes detected before treatment, indicating that these antibodies might help to predict the development of neurological adverse events. Experimental and clinical evidence suggests that post-immune checkpoint inhibitor paraneoplastic neurological syndromes probably share immunological features with spontaneous paraneoplastic syndromes. Hence, the study of post-immune checkpoint inhibitor paraneoplastic neurological syndromes can help in deciphering the immunopathogenesis of paraneoplastic neurological syndromes and in identifying novel therapeutic targets.

Changing landscape in the field of paraneoplastic neurology: Personal perspectives over a 35-year career

Paraneoplastic neurologic syndromes are a group of rare disorders that have fascinated neurologists for more than a century. The discovery in the 1980s that many of these disorders occurred in association with antibodies against neuronal proteins revived the interest for these diseases. This chapter first traces the history of the paraneoplastic neurologic syndromes during the era that preceded the discovery of immune mechanisms and then reviews the immunologic period during which many of these syndromes were found to be associated with antibodies against intracellular onconeuronal proteins and pathogenic cytotoxic T-cell mechanisms. Alongside these developments, investigations on the antibody-mediated disorders of the peripheral nervous system, such as the myasthenic syndromes or neuromyotonia, provided suggestions for the study of the central nervous system (CNS) syndromes. These converging areas of research culminated with the groundbreaking discovery of a new category of CNS disorders mediated by antibodies against neuronal surface proteins or receptors. These disorders are not always paraneoplastic, and the understanding of these syndromes and mechanisms has changed the landscape of neurology and neurosciences.

The immunopathogenesis of narcolepsy type 1

Narcolepsy type 1 (NT1) is a chronic sleep disorder resulting from the loss of a small population of hypothalamic neurons that produce wake-promoting hypocretin (HCRT; also known as orexin) peptides. An immune-mediated pathology for NT1 has long been suspected given its exceptionally tight association with the MHC class II allele HLA-DQB1*06:02, as well as recent genetic evidence showing associations with polymorphisms of T cell receptor genes and other immune-relevant loci and the increased incidence of NT1 that has been observed after vaccination with the influenza vaccine Pandemrix. The search for both self-antigens and foreign antigens recognized by the pathogenic T cell response in NT1 is ongoing. Increased T cell reactivity against HCRT has been consistently reported in patients with NT1, but data demonstrating a primary role for T cells in neuronal destruction are currently lacking. Animal models are providing clues regarding the roles of autoreactive CD4+ and CD8+ T cells in the disease. Elucidation of the pathogenesis of NT1 will allow for the development of targeted immunotherapies at disease onset and could serve as a model for other immune-mediated neurological diseases.

Paraneoplastic/autoimmune myelopathies

Paraneoplastic myelopathies are a rare but important category of myelopathy. They usually present with an insidious or subacute progressive neurologic syndrome. Risk factors include tobacco use and family history of cancer. Cerebrospinal fluid analysis usually shows lymphocytic pleocytosis with elevated protein. MRI findings suggest that paraneoplastic myelopathies include longitudinally extensive T2 hyperintensities that are tract-specific and accompanied by enhancement, but spinal MRIs can also be normal. The most commonly associated neural antibodies include amphiphysin and collapsin-response-mediator-protein-5 (CRMP5/anti-CV2) antibodies with lung and breast cancers being the most frequent oncologic accompaniments. The differential diagnosis of paraneoplastic myelopathies includes nutritional deficiency myelopathy (B12, copper) as well as autoimmune/inflammatory conditions such as primary progressive multiple sclerosis or spinal cord sarcoidosis. Patients treated with immune checkpoint inhibitors for cancer may develop myelitis, that can be considered along the spectrum of paraneoplastic myelopathies. Management of paraneoplastic myelopathy includes oncologic treatment and immunotherapy. Despite these treatments, the prognosis is poor and the majority of patients eventually become wheelchair-dependent.

Expression analysis of inhibitory B7 family members in Alzheimer's disease

Alzheimer's disease (AD) is a global health problem due to its complexity, which frequently makes the development of treatment methods extremely difficult. Therefore, new methodologies are necessary to investigate the pathophysiology of AD and to treat AD. The interaction of immune modulation and neurodegeneration has added new dimensions in current knowledge of AD etiology and offers an attractive opportunity for the discovery of novel biomarkers and therapies. Using quantitative polymerase chain reaction, we compared the expression levels of inhibitory B7 family members (B7-1, B7-2, B7-H1, B7-DC, B7-H3, B7-H4, B7-H5, B7-H7, and ILDR2), as immune regulators, in the peripheral blood of late-onset AD (LOAD) patients (n = 50) and healthy individuals (n = 50). The levels of B7-2, B7-H4, ILDR2, and B7-DC expression were significantly higher in-patient blood samples than in control blood samples. Furthermore, we discovered a substantial positive correlation between all gene expression levels. In addition, the current study indicated that ILDR2, B7-H4, B7-2, and B7-DC might serve as diagnostic biomarkers to identify LOAD patients from healthy persons. The present work provides additional evidence for the significance of inhibitory B7 family members to the etiology of LOAD.

Regression of a melanoma brain metastasis that had appeared after immune checkpoint inhibitor discontinuation: a hypothesis-generating case

We present the case of a 50-year-old woman previously treated with nivolumab-ipilimumab combination therapy for a metastatic melanoma. Despite premature discontinuation of these immune checkpoint inhibitors (ICIs) after 2 cycles due to severe immune-related hepatitis, the patient achieved a complete response. Nine months later, brain magnetic resonance imaging (MRI) showed progression of a single cerebral lesion, and the patient was referred for stereotactic radiosurgery. Unexpectedly, the brain MRI acquired one month later as part of radiosurgery planning showed a spontaneous regression of this lesion, allowing for radiosurgery cancellation. Follow-up imaging showed a sustained response, although the patient did not receive any other oncological treatment. We discuss here the potential immune mechanisms involved in this unusual course and the importance of better understanding the behaviour of tumours in the era of ICIs.

Immune Checkpoint Inhibitors in Patients with Pre-existing Neurologic Autoimmune Disorders

PURPOSE OF REVIEW

The use of immune checkpoint inhibitors (ICIs) for oncologic indications is associated with immune-related adverse events (irAEs). Patients with pre-existing autoimmune diseases are at increased risk of irAEs and have largely been excluded from clinical trials of ICIs. Therefore, there is limited data on the safety of safety of ICIs in patients with pre-existing neurologic autoimmune diseases (nAIDs) such as myasthenia gravis and multiple sclerosis. This review aims to synthesize the literature on the post-marketing experience with ICI in patients with pre-existing nAID and to discuss possible strategies for mitigating the risk of post-ICI nAID relapses.

RECENT FINDINGS

Patients with pre-existing myasthenia gravis (MG), myositis, and paraneoplastic encephalitis appear highly susceptible to neurologic relapses of their underlying neurologic disorder following ICI initiation; these relapses can cause considerable morbidity and mortality. In patients with multiple sclerosis (MS), the risk and severity of MS relapses following ICI appears to be relatively lower compared to MG. Preliminary evidence suggests that older MS patients with no recent focal neuroinflammatory activity may be safely treated with ICI. Among the several case reports of ICI in patients with a history of Guillain-Barre syndrome (GBS), neurologic worsening was only recorded in one patient who was in the acute phase of GBS at the time of ICI start. Initiating an ICI in a patient with pre-existing nAID involves a complex risk-benefit discussion between the patient, their oncologist, and neurologist. Relevant issues to consider before ICI include the choice of disease-modifying therapy for nAID (if any) and strategies for promptly identifying and managing nAID relapses should they occur. Currently, the literature consists mainly of case reports and case series, subject to publication bias. Prospective studies of ICI in patients with nAID are needed to improve the level of evidence.

Nivolumab-induced sensory ganglionopathy

INTRODUCTION

Nivolumab is s a human monoclonal antibody. Due to its widespread use in many cancers, including Merkel cell carcinoma, adverse reactions associated with nivolumab, such as neuropathies, endocrinopathies, gastrointestinal problems, and skin toxicities have been increasing. Sensory ganlionopathy is rarely observed in these patients.

CASE DESCRIPTION

We present a 63-year-old male with a medical history of Merkel cell carcinoma that recurred two times in the inguinal region. After undergoing surgery with adjuvant radiotherapy, a second surgery was performed. The patient suffered from tingling in all four limbs plus difficulty in walking after initiation of the third dose of nivolumab.

MANAGEMENT AND OUTCOME

After 1 month of 1 mg/kg/day methylprednisolone treatment, he showed significant improvement. Subsequently, the systemic corticosteroid regimen was tapered to 5 mg every other day. The treatment resulted in significant improvement in all extremities.

DISCUSSION

Sensory ganlionopathy can be seen as a side effect of an immune checkpoint inhibitor, even though it is very extraordinary. This is the case in the literature to develop sensory ganlionopathy due to nivolumab. We believe that patients using nivolumab may develop sensory ganlionopathy and management should be taken on this point.

MICROGLIAL CELL EXPRESSION OF THE TYPE 2 CANNABINOID RECEPTOR REGULATES IMMUNE-MEDIATED NEUROINFLAMMATION

Neuroinflammation is a recognized complication of immunotherapeutic approaches such as immune checkpoint inhibitor treatment, chimeric antigen receptor therapy, and graft versus host disease (GVHD) occurring after allogeneic hematopoietic stem cell transplantation. While T cells and inflammatory cytokines play a role in this process, the precise interplay between the adaptive and innate arms of the immune system that propagates inflammation in the central nervous system remains incompletely understood. Using a murine model of GVHD, we demonstrate that type 2 cannabinoid receptor (CB2R) signaling plays a critical role in the pathophysiology of neuroinflammation. In these studies, we identify that CB2R expression on microglial cells induces an activated inflammatory phenotype which potentiates the accumulation of donor-derived proinflammatory T cells, regulates chemokine gene regulatory networks, and promotes neuronal cell death. Pharmacological targeting of this receptor with a brain penetrant CB2R inverse agonist/antagonist selectively reduces neuroinflammation without deleteriously affecting systemic GVHD severity. Thus, these findings delineate a therapeutically targetable neuroinflammatory pathway and has implications for the attenuation of neurotoxicity after GVHD and potentially other T cell-based immunotherapeutic approaches.

Immune checkpoint biology in health & disease: Immune checkpoint biology and autoimmunity in cancer patients

Immune checkpoints (ICs) play a central role in maintaining immune homoeostasis. The discovery that tumours use this physiological mechanism to avoid elimination by the immune system, opened up avenues for therapeutic targeting of ICs as a novel way of treating cancer. However, this therapy a new array of autoimmune side effects, termed immune-related adverse events (irAEs). In this narrative review, we first recapitulate the physiological function of ICs that are approved targets for cancer immunotherapy (CTLA-4, PD-(L)1 and LAG-3), as the groundwork to critically discuss current knowledge on irAEs. Specifically, we summarize clinical aspects and examine a molecular classification and predisposing factors of irAEs. Finally, we discuss irAE treatment, particularly emphasizing how molecular knowledge is changing the current treatment paradigm.

Activating Nanomedicines with Electromagnetic Energy for Deep-Tissue Induction of Immunogenic Cell Death in Cancer Immunotherapy

Immunotherapy is an attractive approach for cancer therapy, while its antitumor efficacy is still limited, especially for non-immunogenic tumors. Nanomedicines can be utilized to convert the non-immunogenic "cold" tumors to immunogenic "hot" tumors via inducing immunogenic cell death (ICD), thereby promoting the antitumor immune response. Some nanomedicines that can produce local heat and reactive oxygen species upon the stimulation of electromagnetic energy are the main candidates for inducing the ICD effect. However, their applications are often restricted due to the poor tissue penetration depths of electromagnetic energy, such as light. By contrast, ultrasound, X-ray, alternating magnetic field, and microwave show excellent tissue penetration depths and thereby can be used for sonodynamic therapy, radiotherapy, magnetic hyperthermia therapy, and microwave ablation therapy, all of which can effectively induce ICD. Herein, the combination of deep-tissue electromagnetic energy with nanomedicines for inducing ICD and cancer immunotherapy are summarized. In particular, the designs of nanomedicines to amplify ICD effect in the presence of deep-tissue electromagnetic energy and sensitize tumors to various immunotherapies will be discussed. At the end of this review, a brief conclusion and discussion of current challenges and further perspectives in this subfield are provided.

Evaluation and management of acute high-grade immunotherapy-related neurotoxicity

Immune checkpoint inhibitor monoclonal antibodies allow the host's immune system to attack tumors, which has revolutionized cancer care over the last decade. As the use of immune checkpoint inhibitors has expanded, so have autoimmune-like complications known as immune-related adverse events. These include the infrequent but increasingly more common, potentially deadly neurological immune related adverse events. When feeling acutely ill, patients will often seek care not from their oncologist but from their family physician, clinics, emergency, and urgent care sites, or other available providers. Thus, while assessing acutely ill cancer patients who are experiencing neurological symptoms, non-oncologists should be prepared to recognize, diagnose, and treat neurological immune related adverse events in addition to more familiar conditions. This narrative review is designed to update acute care clinicians on current knowledge and to present a symptom-based framework for evaluating and treating neurological immune related adverse events based on the leading immunotoxicity organizations' latest recommendations.

Case series: Immune checkpoint inhibitor-induced transverse myelitis

Introduction

Increasing implementation of the highly efficacious immune checkpoint inhibitors (ICIs) has raised awareness of their various complications in the form of immune-related adverse events (irAEs). Transverse myelitis following ICIs is thought to be a rare but serious neurologic irAE and knowledge is limited about this distinct clinical entity.

Cases

We describe four patients across three tertiary centers in Australia with ICI-induced transverse myelitis. Three patients had a diagnosis of stage III-IV melanoma treated with nivolumab and one patient had stage IV non-small cell lung cancer treated with pembrolizumab. All patients had longitudinally extensive transverse myelitis on magnetic resonance imaging (MRI) spine and clinical presentation was accompanied by inflammatory cerebrospinal fluid (CSF) findings. Half of our cohort had received spinal radiotherapy, with the areas of transverse myelitis extending beyond the level of previous radiation field. Inflammatory changes on neuroimaging did not extend to the brain parenchyma or caudal nerve roots, except for one case involving the conus medullaris. All patients received high dose glucocorticoids as first-line therapy, however the majority relapsed or had a refractory state (3/4) despite this, requiring escalation of their immunomodulation, with either induction intravenous immunoglobulin (IVIg) or plasmapheresis. Patients in our cohort who relapsed had a poorer outcome with more severe disability and reduced functional independence following resolution of their myelitis. Two patients had no progression of their malignancy and two patients had malignancy progression. Of the three patients who survived, two had resolution of their neurological symptoms and one remained symptomatic.

Conclusion

We propose that prompt intensive immunomodulation is favored for patients with ICI-transverse myelitis in an attempt to reduce associated significant morbidity and mortality. Furthermore, there is a significant risk of relapse following cessation of immunomodulatory therapy. We suggest one treatment approach of IVMP and induction IVIg for all patients presenting with ICI-induced transverse myelitis based on such findings. With the increasing use of ICIs across oncology, further studies are required to explore this neurological phenomenon in greater detail to help establish management consensus guidelines.

Neurology of cancer immunotherapy

BACKGROUND

Immunotherapy is nowadays considered a mainstay of cancer treatment, dramatically affecting the disease-free survival rate in several aggressive malignancies. Unfortunately, cancer immunotherapy can also trigger life-threatening autoimmune neurological complications named "neurological adverse effects" (NAEs). NAEs can affect both the central nervous system (CNS), as in ipilimumab-related aseptic meningitis, and the peripheral nervous system (PNS), as in nivolumab-induced myasthenia gravis.

CURRENT EVIDENCE

The incidence of NAEs is highly variable, ranging from 2 to 4% using checkpoint inhibitors to 50% using blinatumomab. Looking at these numbers, it appears clear that neurologists will soon be called more and more frequently to decide upon the best therapeutic strategy for a patient receiving immunotherapy and experiencing a NAE. Most of them can be treated or reverted withholding the offending drug and adding IVIg, plasmapheresis, or steroids to the therapy. Sometimes, however, for oncological reasons, immunotherapy cannot be stopped so the neurologist needs to know what countermeasures have proven most effective. Moreover, patients with a pre-existing autoimmune neurological disease (AID), such as myasthenia gravis or multiple sclerosis, might need immunotherapy during their life, risking a severe worsening of their symptoms. In that setting, the neurologist needs to properly counsel patients about the risk of a therapy-related relapse.

CONCLUSION

In this article, we describe the most frequently reported NAEs and aim to give neurologists a practical overview on how to deal with them.

Neurological Complications of Conventional and Novel Anticancer Treatments

Various neurological complications, affecting both the central and peripheral nervous system, can frequently be experienced by cancer survivors after exposure to conventional chemotherapy, but also to modern immunotherapy. In this review, we provide an overview of the most well-known adverse events related to chemotherapy, with a focus on chemotherapy induced peripheral neurotoxicity, but we also address some emerging novel clinical entities related to cancer treatment, including chemotherapy-related cognitive impairment and immune-mediated adverse events. Unfortunately, efficacious curative or preventive treatment for all these neurological complications is still lacking. We provide a description of the possible mechanisms involved to drive future drug discovery in this field, both for symptomatic treatment and neuroprotection.

Anti-Hu Antibodies in Patients With Neurologic Side Effects of Immune Checkpoint Inhibitors

BACKGROUND AND OBJECTIVES

To clinically characterize post-immune checkpoint inhibitor (ICI) Hu antibody (Ab) neurologic disorders, we analyzed Hu-Ab-positive patients with neurologic immune-related adverse events (n-irAEs) and compared them with patients with other n-irAEs, ICI-naive patients with Hu-Ab paraneoplastic neurologic syndromes (PNSs) identified in the same study center, and those with Hu-Ab n-irAEs reported elsewhere.

METHODS

Patients whose samples were sent to the French reference center for a suspicion of n-irAE (2015-2021) were identified; those with a final diagnosis of n-irAE and Hu-Ab were included. Control groups included patients with a final diagnosis of n-irAE occurring during the same period as the patients included (2018-2021) but without Hu-Ab, and ICI-naive patients with Hu-Ab PNS diagnosed during the same period; a systematic review was performed to identify previous reports.

RESULTS

Eleven patients with Hu-Ab and n-irAEs were included (median age, 66 years, range 44-76 years; 73% men). Ten patients had small cell lung cancer, and 1 had lung adenocarcinoma. The median follow-up from onset was 3 months (range 0.5-18 months). Compared with those with other n-irAEs (n = 63), Hu-Ab-positive patients had more frequently co-occurring involvement of both central and peripheral nervous systems (36% vs 8%, p = 0.02) and limbic (54% vs 14%, p < 0.01), brainstem (27% vs 5%, p = 0.02), and dorsal root ganglia (45% vs 5%, p < 0.01) involvement. The proportion of patients with severe disability (modified Rankin Scale score >3) at diagnosis was higher among Hu-Ab n-irAEs (91% vs 52%, p = 0.02). Patients with Hu-Ab had also poorer outcome (100% vs 28%, p < 0.01) and higher mortality (91% vs 46%, p < 0.01). There was no significant difference in terms of clinical features between Hu-Ab n-irAEs and ICI-naive Hu-Ab PNS (n = 92), but there was a poorer outcome (56/78, 71%, p < 0.01) and higher mortality (26%, p < 0.01) among the former. No significant difference was found between the patients reported herein and those in the literature.

DISCUSSION

The presence of Hu-Ab identifies a subgroup of n-irAEs that consistently reproduce the phenotypes of Hu-Ab-related PNS, supporting the hypothesis of ICI triggering or unmasking PNS. As these patients show high disability and mortality, further studies are required to investigate the underlying immunopathogenic mechanisms and to improve the outcome of Hu-Ab n-irAEs.

Hypophysitis induced by anti-programmed cell death protein 1 immunotherapy in non-small cell lung cancer: Three case reports

BACKGROUND

Hypophysitis induced by programmed cell death 1 protein (PD-1) immune checkpoint inhibitors is rare and poorly described. We report three patients with non-small cell lung cancer who developed hypophysitis after anti-PD-1 immunotherapy.

CASE SUMMARY

Both case 1 and case 2 presented with common symptoms of fatigue, nausea, and vomiting. However, case 3 showed rare acute severe symptoms such as hoarse voice, bucking, and difficulty in breathing even when sitting. Following two cycles of immunotherapy in case 3, the above severe symptoms and pituitary gland enlargement were found on magnetic resonance imaging at the onset of hypophysitis. These symptoms were relieved after 10 d of steroid treatment. Case 3 was the first patient with these specific symptoms, which provided a new insight into the diagnosis of hypophysitis. In addition, we found that the clinical prognosis of patients with hypophysitis was related to the dose of steroid therapy. Case 3 was treated with high-dose hormone therapy and her pituitary-corticotropic axis dysfunction returned to normal after more than 6 mo of steroid treatment. Cases 1 and 2 were treated with the low-dose hormone, and dysfunction of the pituitary-corticotropic axis was still present after up to 7 mo of steroid treatment.

CONCLUSION

The clinical symptoms described in this study provide a valuable reference for the diagnosis and treatment of immune-related hypophysitis.

Drug-related immune-mediated myelopathies

Iatrogenic immune-mediated inflammatory disorders of the spinal cord are an uncommon but potentially severe complication of drug therapy for several human diseases. Particularly the introduction of novel biological agents in the treatment of systemic inflammatory disorders and cancer immunotherapy have led to a significant increase in immune-related adverse events of the central nervous system (CNS). The use of Tumor necrosis factor alpha (TNF-alpha) inhibitors in rheumatic and inflammatory bowel diseases has been associated with demyelinating and other inflammatory CNS conditions, including myelitis. The introduction of immune checkpoint inhibitors in the treatment of several human malignancies has led to an increase in drug-induced immune-related adverse events including in the CNS. Other drugs that have been associated with immune-mediated myelitis include tyrosine-kinase inhibitors and chimeric antigen receptor (CAR) T Cell therapy. A high degree of suspicion is necessary when diagnosing these conditions, as early diagnosis and treatment is crucial in preventing further neurological damage and disability. The treatment of drug-induced inflammatory myelitis typically involves administration of high-dose intravenous corticosteroids, however additional immunosuppressive agents may be required in severe or refractory cases. While most cases are monophasic and remit following discontinuation of the offending agent, chronic immunosuppressive therapy may be indicated in cases with a progressive or relapsing disease course or when a diagnosis of a specific underlying neuro-inflammatory disorder is made. Outcomes are generally favorable, however depend on the specific therapeutic agent used, the clinical presentation and patient factors. In this review we aim to describe the clinical characteristics, imaging findings and management for the most common forms of iatrogenic immune-mediated myelopathies.

Novelties in Autoimmune and Paraneoplastic Cerebellar Ataxias: Twenty Years of Progresses

Major advances in our knowledge concerning autoimmune and paraneoplastic cerebellar ataxias have occurred in the last 20 years. The discovery of several neural antibodies represents an undeniable contribution to this field, especially those serving as good biomarkers of paraneoplastic neurological syndromes and those showing direct pathogenic effects. Yet, many patients still lack detectable or known antibodies, and also many antibodies have only been reported in few patients, which makes it difficult to define in detail their clinical value. Nevertheless, a notable progress has additionally been made in the clinical characterization of patients with the main neural antibodies, which, although typically present with a subacute pancerebellar syndrome, may also show either hyperacute or chronic onsets that complicate the differential diagnoses. However, prodromal and transient features could be useful clues for an early recognition, and extracerebellar involvement may also be highly indicative of the associated antibody. Moreover, important advances in our understanding of the pathogenesis of cerebellar ataxias include the description of antibody effects, especially those targeting cell-surface antigens, and first attempts to isolate antigen-specific T-cells. Furthermore, genetic predisposition seems relevant, although differently involved according to cancer association, with particular HLA observed in non-paraneoplastic cases and genetic abnormalities in the tumor cells in paraneoplastic ones. Finally, immune checkpoint inhibitors used as cancer immunotherapy may rarely induce cerebellar ataxias, but even this undesirable effect may in turn serve to shed some light on their physiopathology. Herein, we review the principal novelties of the last 20 years regarding autoimmune and paraneoplastic cerebellar ataxias.

A prodrug hydrogel with tumor microenvironment and near-infrared light dual-responsive action for synergistic cancer immunotherapy

Immunotherapy has been used for cancer treatment, while it faces the common dilemmas of low therapeutic efficacy and serious immunotoxicity. In this study, we report the construction of a tumor microenvironment and near-infrared (NIR) light dual-responsive prodrug hydrogel for cancer synergistic immunotherapy in a more effective and safe manner. Such prodrug hydrogels were in-situ formed via calcium-induced gelation of alginate solution containing protoporphyrin IX (PpIX)-modified iron oxide (Fe₃O₄) nanoparticles and programmed death ligand 1 antibody (aPD-L1) prodrug nanoparticles crosslinked by reactive oxygen species (ROS)-responsive linkers. PpIX served as a photosensitizer to produce singlet oxygen (¹O₂) under NIR laser irradiation for photodynamic therapy (PDT), and Fe₃O₄ nanoparticles mediated chemodynamic therapy (CDT) to generate hydroxyl radical (·OH) via Fenton reaction in the tumor microenvironment. In view of the cumulative actions of PDT and CDT, amplified ROS was generated to not only induce immunogenic cell death (ICD), but also destroy ROS-responsive linkers to achieve on-demand release of aPD-L1 from prodrug nanoparticles. Boosted antitumor immunity was elicited in tumor-bearing mice due to the aPD-L1-mediated immune checkpoint blocking. As a result, the prodrug hydrogel-based synergistic immunotherapy could almost treat bilateral tumors and prevent lung and liver metastasis using 4T1 tumor mouse models. This study thus offers a dual-responsive prodrug hydrogel platform for precision cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Via calcium-induced gelation of alginate, we constructed a prodrug hydrogel with tumor microenvironment and near-infrared light dual-responsive action for synergistic cancer immunotherapy. Such hydrogels can achieve on-demand release of aPD-L1 upon photoactivation in the tumor microenvironment. Through mediating photodynamic and chemodynamic therapy, the prodrug hydrogels can induce enhanced immunogenic cell death and synergistically improve the efficacy of aPD-L1-mediated immune checkpoint blocking. The prodrug hydrogel-based synergistic therapy almost deracinates the primary and distant tumors, and prevents lung and liver metastasis in tumor mouse models.

Immune Checkpoint Inhibitor Associated Autoimmune Encephalitis, Rare and Novel Topic of Neuroimmunology: A Case Report and Review of the Literature

Immune checkpoint inhibitors (ICIs) are being used in patients with various advanced malignancies, and patient outcomes have improved considerably. Although ICIs can effectively treat tumors, 30-60% of patients experience immune-related adverse events (irAEs). Autoimmune encephalitis (AE) is a rare irAE that has become a novel topic in neuroimmunology and has received increasing attention in recent years. Herein, we report a rare case of GAD65-antibody-associated AE after metastatic small cell lung cancer treatment with pembrolizumab. The patient received IVIg therapy for AE and continuous pembrolizumab therapy without suspension of tumor treatment. At 1 year follow-up, both the patient's AE symptoms and tumors were stable. We consider that the treatment of ICI-associated AE should be more individualized with prudent decision-making and should balance the tumor progression and AE treatment. In addition, we have also comprehensively reviewed the literature of ICI-associated AE, and summarized the clinical features, treatment, and prognosis of AE caused by ICI, thus broadening our understanding of the neurological complications caused by ICI.

[A case of myopathy, myocarditis, and encephalitis with nonconvulsive status epileptics after immune checkpoint inhibitor therapy for ureter cancer]

A 72-year-old man, who had received pembrolizumab of immune checkpoint inhibitor (ICI) over 6 months for ureter cancer, developed progressive skeletal muscle weakness, dysarthria, dyspnea, and consciousness disturbance over the past two weeks. The systemic work-up tests documented an encephalitis, myopathy, and myocarditis. Multiple autoimmune antibodies of anti-Tr, anti-titin, anti-kv1.4, anti-GM1 and anti-GD1a were positive in the serum. Although myopathy and myocarditis responded to high-dose steroid pulse therapy, encephalopathy deteriorated. Electroencephalogram showed a fluctuated pattern of rhythmic delta activity with fast waves, and a rapid response to intravenous diazepam revealed a condition of nonconvulsive status epileptics (NCSE). The patient had an uneventful course after anti-epileptic medication. The ICIs therapy may trigger a broader activation of multiple autoimmune mechanisms. When an encephalitis by immune-related adverse events does not respond to standard immunotherapy, NCSE may be a main pathophysiological mechanism, thereby anti-epileptics being an alternative treatment option.

Bifunctional Pdots-Based Novel ECL Nanoprobe with Qualitative and Quantitative Dual Signal Amplification Characteristics for Trace Cytokine Analysis

In this work, a novel methodology to design bifunctional ECL-luminophores with self-enhanced and TSA-amplified characteristics was proposed for improving the sensing performance of ECL-immunosensor toward trace cytokine analysis. Thanks to the qualitative- and quantitative- dual signal amplification technique, the as-prepared ECL biosensor demonstrated excellent detection performance. By analyzing the prospective cytokine biomarkers (IL-6), the ECL immunosensor exhibited a broad examination range with quite low detection limit and quite high selectivity, which was far superior to commercial ELISA kits and ever reported works. In particular, the novel ECL nanoprobe developed here could also be applied to monitor other immune toxicities or disease-related cytokines by using the respective antibodies corresponding to these targets. Moreover, the concept and construction strategy of self-amplified ECL-luminophores presented here could be further extended to design a series of Pdots-derived multicolored ECL probes to meet the needs of multipathway detection applications.

Immune-related aseptic meningitis and strategies to manage immune checkpoint inhibitor therapy: a systematic review

INTRODUCTION

Immune checkpoint inhibitors (ICIs) can induce adverse neurological effects. Due to its rarity as an adverse effect, meningitis has been poorly described. Therefore, meningitis diagnosis and management can be challenging for specialists. Moreover, meningitis can be an obstacle to resuming immunotherapy. Given the lack of alternatives, the possibility of reintroducing immunotherapy should be discussed on an individual basis. Here, we present a comprehensive systematic review of meningitis related to ICIs.

REVIEW

We performed a search for articles regarding immune-related meningitis published in PubMed up to November 2021 with the MeSH terms "meningitis" and "immune checkpoint" using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. We summarized the studies not only by category but also based on whether it was a primary article or case report to provide a systematic overview of the subject. We reviewed a total of 38 studies and herein report the clinical experiences, pharmacovigilance data and group knowledge from these studies.

CONCLUSION

This review summarizes the existing information on immune-related meningitis and the possibility of reintroducing immunotherapy after the development of central neurological side effects. To the best of our knowledge, there is little information in the literature to guide clinicians on decisions regarding whether immunotherapy should be continued after a neurological adverse event occurs, especially meningeal events. This review emphasizes the necessity of systematic examinations, steroid treatment (as a cornerstone of management) and the need for further exploratory studies to obtain a clearer understanding of how to better manage patients who experience these side effects. The findings summarized in this review can help provide guidance to practitioners who face this clinical situation.

Review: Neurological Complications From Therapies for Pediatric Brain Tumors

Surgery, chemotherapy and radiation have been the mainstay of pediatric brain tumor treatment over the past decades. Recently, new treatment modalities have emerged for the management of pediatric brain tumors. These therapies range from novel radiotherapy techniques and targeted immunotherapies to checkpoint inhibitors and T cell transfer therapies. These treatments are currently investigated with the goal of improving survival and decreasing morbidity. However, compared to traditional therapies, these novel modalities are not as well elucidated and similarly has the potential to cause significant short and long-term sequelae, impacting quality of life. Treatment complications are commonly mediated through direct drug toxicity or vascular, infectious, or autoimmune mechanisms, ranging from immune effector cell associated neurotoxicity syndrome with CART-cells to neuropathy with checkpoint inhibitors. Addressing treatment-induced complications is the focus of new trials, specifically improving neurocognitive outcomes. The aim of this review is to explore the pathophysiology underlying treatment related neurologic side effects, highlight associated complications, and describe the future direction of brain tumor protocols. Increasing awareness of these neurologic complications from novel therapies underscores the need for quality-of-life metrics and considerations in clinical trials to decrease associated treatment-induced morbidity.

Case Report: Neuromyelitis Optica After Treatment of Uveal Melanoma With Nivolumab and Ipilimumab

The development of immune checkpoint inhibitors (ICIs) has greatly improved survival of patients with advanced malignancies. ICIs can cause immune-related adverse effects (irAEs) involving any organ. Neurological irAEs are infrequent and have mostly been reported in patients with melanoma. We describe the case of a 57-year-old male with right eye uveal melanoma, gene expression profile (class 2), and PRAME (preferentially expressed antigen in melanoma) positivity, who received plaque brachytherapy with Iodine-125 for 4 days with subsequent adjuvant ICIs (immune checkpoint inhibitors), nivolumab and ipilimumab. 18 weeks after discontinuation of immunotherapy, the patient presented with acute onset of left-sided headaches, pain with eye movements, and vision loss. The patient was tested positive for serum anti-aquaporin-4 antibody (AQP4-Ab) and was diagnosed with neuromyelitis optica spectrum disorder (NMOSD). Subsequently, he was treated with 5 days of intravenous methylprednisolone followed by an oral prednisone taper over 10 weeks, with improvement in symptoms. We report a unique case of neuromyelitis optica spectrum disorder (NMOSD) following treatment with ICIs. To our best knowledge, this is the third reported case in English literature of NMOSD following ICI therapy and the first reported case of NMOSD caused by ICI treatment in uveal melanoma.

Study on the pro-inflammatory mechanism of the HuD antibody in promoting M1 polarization and paraneoplastic neurological syndrome occurrence

Paraneoplastic neurological syndrome (PNS) is a nonmetastatic complication of malignant tumors that may lead to immune-mediated neuronal dysfunction or death. The occurrence of PNS results from the binding of anti-neuronal antibodies to neuronal cell surface antigens or intracellular antigens, which hinders the function of target proteins and promotes cell death. The aim of this study is to research the effect and immune mechanism of the neuronal ELAV-like protein (HuD antibody) on PNS-related syndrome. Neuronal cells were co-cultured with monocyte macrophages with or without HuD antibody. Next, we detected the apoptosis of neuronal cells by flow cytometry. Meantime, macrophage M1/M2 polarization factors and the secretion of inflammatory factors in the co-culture system were also detected by quantitative polymerase chain reaction (qPCR), Western blots and ELISA technologies. The results showed that after adding the HuD antibody in the co-culture system, the apoptosis level of the neuroma cells were significantly increased, and the apoptosis level were not significant changed when co-culture with monocytes without HuD antibody. In addition, the level of factors of M1 macrophages TNF-α, IL-12, TGF-β and IFN-γ increased, while the level of factors of M2 macrophages IL-10, IL-4, and Arg-1 decreased. The outcomes demonstrated that absorption of the HuD antibody by cerebellar neuronal cells could promote the proliferation of M1 macrophages and stimulates macrophages to secrete inflammatory factors, further damage the neuronal cells, eventually resulting in the occurrence of PNS. This finding provided a theoretical basis for the subsequent treatment and prevention of PNS.

Brain Vascular Microenvironments in Cancer Metastasis

Primary tumours, particularly from major solid organs, are able to disseminate into the blood and lymphatic system and spread to distant sites. These secondary metastases to other major organs are the most lethal aspect of cancer, accounting for the majority of cancer deaths. The brain is a frequent site of metastasis, and brain metastases are often fatal due to the critical role of the nervous system and the limited options for treatment, including surgery. This creates a need to further understand the complex cell and molecular biology associated with the establishment of brain metastasis, including the changes to the environment of the brain to enable the arrival and growth of tumour cells. Local changes in the vascular network, immune system and stromal components all have the potential to recruit and foster metastatic tumour cells. This review summarises our current understanding of brain vascular microenvironments, fluid circulation and drainage in the context of brain metastases, as well as commenting on current cutting-edge experimental approaches used to investigate changes in vascular environments and alterations in specialised subsets of blood and lymphatic vessel cells during cancer spread to the brain.

Cognitive adverse effects of chemotherapy and immunotherapy: are interventions within reach?

One in three people will be diagnosed with cancer during their lifetime. The community of cancer patients is growing, and several common cancers are becoming increasingly chronic; thus, cancer survivorship is an important part of health care. A large body of research indicates that cancer and cancer therapies are associated with cognitive impairment. This research has mainly concentrated on chemotherapy-associated cognitive impairment but, with the arrival of immunotherapies, the focus is expected to widen and the number of studies investigating the potential cognitive effects of these new therapies is rising. Meanwhile, patients with cognitive impairment and their healthcare providers are eagerly awaiting effective approaches to intervene against the cognitive effects of cancer treatment. In this Review, we take stock of the progress that has been made and discuss the steps that need to be taken to accelerate research into the biology underlying cognitive decline following chemotherapy and immunotherapy and to develop restorative and preventive interventions. We also provide recommendations to clinicians on how to best help patients who are currently experiencing cognitive impairment.

The Occurrence of Encephalitis Due to Immune Checkpoint Inhibitors: A Pharmacovigilance Study

PURPOSE

Immune checkpoint inhibitors (ICIs) are associated with peculiar adverse events related to the mechanism of action. Less than 1% of patients treated with ICIs develop autoimmune encephalitis. The aim of this study was to compare the frequency of encephalitis development due to ICIs with encephalitis due to other drugs using the Japanese Adverse Drug Event Report (JADER) database and Bayesian confidence propagation neural networks for signal detection.

METHODS

Data from the JADER database from April 2004 to December 2020 were downloaded via the Pharmaceuticals and Medical Devices Agency (PMDA) website. The Information Component (IC) values were calculated as an index of signal detection based on the Bayesian method.

RESULTS

The lower bound of the 95% credible interval (CI) of the IC values for atezolizumab and pembrolizumab were greater than 0 in most of the periods. Thus, encephalitis occurred more frequently for atezolizumab and pembrolizumab than for other drugs. For nivolumab and ipilimumab, a significant signal was detected only for recent data. In contrast, the lower bounds of the 95% CIs for avelumab and durvalumab were smaller than 0 in most of the periods because encephalitis was seldom reported for avelumab and durvalumab.

CONCLUSIONS

We showed that encephalitis occurs more frequently for atezolizumab, pembrolizumab, nivolumab, and ipilimumab compared with the frequency for other drugs. The time of onset varied widely, and patients should be monitored for more than 1 year after the last administration of ICIs.

Subacute CNS Demyelination After Treatment With Immune Checkpoint Inhibitors

Immune checkpoints are molecules on the surface of leucocytes which modulate the amplitude of immune responses. Monoclonal antibodies blocking these molecules are known as immune checkpoints inhibitors (ICIs) and have been shown to unleash anti- tumour immunity and mediate durable cancer regressions. ICIs include ipilimumab which blocks the cytotoxic T-lymphocyte antigen-4 (CTLA-4), nivolumab and pembrolizumab which are both against the programmed cell death protein 1 (PD-1)1. The clinical use of these ICIs has led to significantly improved survival in patients with a variety of solid malignancies including melanoma.

Extracellular matrix-degrading STING nanoagonists for mild NIR-II photothermal-augmented chemodynamic-immunotherapy

Regulation of stimulator of interferon genes (STING) pathway using agonists can boost antitumor immunity for cancer treatment, while the rapid plasma clearance, limited membrane permeability, and inefficient cytosolic transport of STING agonists greatly compromise their therapeutic efficacy. In this study, we describe an extracellular matrix (ECM)-degrading nanoagonist (dNAc) with second near-infrared (NIR-II) light controlled activation of intracellular STING pathway for mild photothermal-augmented chemodynamic-immunotherapy of breast cancer. The dNAc consists of a thermal-responsive liposome inside loading with ferrous sulfide (FeS₂) nanoparticles as both NIR-II photothermal converters and Fenton catalysts, 2′3′-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) as the STING agonist, and an ECM-degrading enzyme (bromelain) on the liposome surface. Mild heat generated by dNAc upon NIR-II photoirradiation improves Fenton reaction efficacy to kill tumor cells and cause immunogenic cell death (ICD). Meanwhile, the generated heat triggers a controlled release of cGAMP from thermal-responsive liposomes to active STING pathway. The mild photothermal activation of STING pathway combined with ICD promotes anti-tumor immune responses, which leads to improved infiltration of effector T cells into tumor tissues after bromelain-mediated ECM degradation. As a result, after treatment with dNAc upon NIR-II photoactivation, both primary and distant tumors in a murine mouse model are inhibited and the liver and lung metastasis are effectively suppressed. This work presents a photoactivatable system for STING pathway and combinational immunotherapy with improved therapeutic outcome.

Uncommon inflammatory/immune-related myelopathies

The differential diagnosis for immune-mediated myelopathies is broad. Although clinical manifestations overlap, certain presentations are suggestive of a particular myelopathy etiology. Spine MRI lesion characteristics including the length and location, and the pattern of gadolinium enhancement, help narrow the differential diagnosis and exclude an extrinsic compressive cause. The discovery of specific antibodies that serve as biomarkers of myelitis such as aquaporin-4-IgG and myelin-oligodendrocyte -glycoprotein-IgG (MOG-IgG), has improved our understanding of myelitis pathophysiology and facilitated diagnosis. In this review we will focus on the pathophysiology, clinical presentation, imaging findings and treatment and outcomes of uncommon immune-mediated myelopathies.

Glial Fibrillary Acidic Protein Autoimmunity: A French Cohort Study

Background and Objectives

To report the clinical, biological, and imaging features and clinical course of a French cohort of patients with glial fibrillary acidic protein (GFAP) autoantibodies.

Methods

We retrospectively included all patients who tested positive for GFAP antibodies in the CSF by immunohistochemistry and confirmed by cell-based assay using cells expressing human GFAPα since 2017 from 2 French referral centers.

Results

We identified 46 patients with GFAP antibodies. Median age at onset was 43 years, and 65% were men. Infectious prodromal symptoms were found in 82%. Other autoimmune diseases were found in 22% of patients, and coexisting neural autoantibodies in 11%. Tumors were present in 24%, and T-cell dysfunction in 23%. The most frequent presentation was subacute meningoencephalitis (85%), with cerebellar dysfunction in 57% of cases. Other clinical presentations included myelitis (30%) and visual (35%) and peripheral nervous system involvement (24%). MRI showed perivascular radial enhancement in 32%, periventricular T2 hyperintensity in 41%, brainstem involvement in 31%, leptomeningeal enhancement in 26%, and reversible splenial lesions in 4 cases. A total of 33 of 40 patients had a monophasic course, associated with a good outcome at last follow-up (Rankin Score ≤2: 89%), despite a severe clinical presentation. Adult and pediatric features are similar. Thirty-two patients were treated with immunotherapy. A total of 11/22 patients showed negative conversion of GFAP antibodies.

Discussion

GFAP autoimmunity is mainly associated with acute/subacute meningoencephalomyelitis with prodromal symptoms, for which tumors and T-cell dysfunction are frequent triggers. The majority of patients followed a monophasic course with a good outcome.

Neurological complications induced by immune checkpoint inhibitors: a comprehensive descriptive case-series unravelling high risk of long-term sequelae

Neurological immune-related adverse events are complications of programmed-cell death 1 or programmed-cell death 1 ligand immunotherapies that can be life threatening and often lead to anticancer immunotherapy withdrawal. Scant clinical data are available that integrate the clinical presentation, therapeutic management and long-term outcome. All consecutive adult patients treated by programmed-cell death 1 or programmed-cell death 1 ligand immunotherapies, given alone or in combination with other treatment, who experienced a neurological immune-related adverse event with a severity grade ≥2 in Paris Saclay-University hospitals were investigated from June 2014 to February 2019. The frequency of neurological immune-related adverse events was calculated from the prospective Registre des Effets Indésirables Sévères des Anticorps Monoclonaux Immunomodulateurs en Cancérologie cohort. Forty patients presenting with 51 distinct neurological immune-related adverse events were included. The prevalence of grade ≥2 neurological immune-related adverse events was estimated to be 1.22% in the Registre des Effets Indésirables Sévères des Anticorps Monoclonaux Immunomodulateurs en Cancérologie cohort. Among 40 patients with neurological immune-related adverse events, 65% received programmed-cell death 1 or programmed-cell death 1 ligand monotherapy and 35% received a combination of programmed-cell death 1 plus anti-CTLA4 (Common Terminology Criteria for Adverse Events). Clinical neurological presentations were peripheral (48%), central (35%), or mixed (18%). The severity of neurological immune-related adverse events was grade 2 for 14 (35%) and ≥grade 3 for 26 patients (65%). The mortality rate related to neurological immune-related adverse events was 8%. Corticosteroid treatment led to neurological recovery in 74%. Long-term follow-up highlighted that 53% of patients experienced long-term neurological sequelae. Five patients were rechallenged by programmed-cell death 1 monotherapy without recurrence of their neurological immune-related adverse event(s). Neurological immune-related adverse events induced by programmed-cell death 1 or programmed-cell death 1 ligand are rare but are severe with a mortality rate of 8% and long-term sequelae for 53% of patients. Corticosteroids should be started when neurological immunological complications are identified to avoid long-term sequelae.

A brief report on incidence, radiographic feature and prognostic significance of brain MRI changes after anti-PD-1/PD-L1 therapy in advanced non-small cell lung cancer

INTRODUCTION

Neurologic immune-related adverse events (nirAEs) are uncommon but potentially lethal complications of immune checkpoint inhibitor (ICI) treatment. However, the incidence, radiographic features and prognostic significance of brain magnetic resonance imaging (MRI) changes after ICI treatment remain largely unknown.

METHODS

Consecutive patients with advanced non-small cell lung cancer (NSCLC) at three participating institutions receiving anti-PD-1/PD-L1 therapy from June 2017 to September 2020 were screened, and those who received brain MRI within 6 weeks before ICI initiation and at least one follow-up brain MRI after ICI treatment were included. Serial brain MRI images were independently reviewed by two experienced radiologists.

RESULTS

With a median follow-up of 13.2 months, 27 (20.0%) of the 135 enrolled patients developed certain kind of brain MRI aberration. The 1-, 2- and 3-year cumulative incidence of brain MRI aberration was 17.1%, 36.3% and 52.2%, respectively. Brain MRI aberration indicative of stroke, mimicking typical white matter lesions and presenting as T2-hyperintensity suggestive of CNS vasculitis or encephalitis, was documented in 11, 9 and 4 patients, respectively. Patients with brain MRI aberration had higher clinical benefit rate (p = 0.030), longer progression-free survival (p = 0.015) and a tendency of improved overall survival (p = 0.054).

CONCLUSIONS

Brain MRI aberrations developed after ICI treatment are not uncommon, and their manifestations vary a lot. Patients developing brain MRI aberrations tended to have better prognosis, which needed to be further investigated.