Autoimmune pancerebellitis associated with pembrolizumab therapy

Immune Checkpoint Inhibitor-Related Cerebellar Toxicity: Clinical Features and Comparison with Paraneoplastic Cerebellar Ataxia

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy, and the association with immune-related adverse events (irAEs) is well-established. However, cerebellar irAEs are poorly defined and their relationship with paraneoplastic disorders remains unclear. Our aim was (i) to characterize cerebellar irAE; (ii) to compare it with paraneoplastic cerebellar ataxia (PCA). We performed a multicenter, retrospective, cohort study of patients developing new-onset, immune-mediated, isolated/predominant cerebellar dysfunction after ICI administration. In addition, a systematic review following PRISMA guidelines was performed. Cerebellar irAE cases were compared with a consecutive cohort of patients with PCA. Overall, 35 patients were included, of whom 12 were original cases (males: 25/35 (71%), median age: 65 [range: 20-82]). The most frequent tumor was non-small cell lung cancer (12/35, 34%). Anti-PD1 were adopted in 19/35 (54%). Symptoms developed at a median of 11 weeks after ICI onset. Neuronal antibodies were detected in 15/31 patients tested (48%). Cerebrospinal fluid was inflammatory in 25/30 (83%). Magnetic resonance imaging showed cerebellar hyperintensities in 8/35 (23%). Immunotherapy was applied in 33/35 cases (94%), and most patients improved with residual disability (16/35, 46%). When compared with a series of PCA (n = 15), the cerebellar irAE group was significantly more associated with male sex, lung cancer (rather than gynecological/breast cancers), isolated ataxia, and a better outcome. We provide a detailed characterization of cerebellar irAE. Compared to PCA, differences exist in terms of tumor association, clinical features, and outcome. Clinical presentation-antibody-tumor triad in the ICI group only partially reflects the associations described in paraneoplastic disorders.

Clinical utility of square-wave jerks in neurology and psychiatry

Human eye fixation is steadily interrupted by small, physiological or abnormal, eye movements. Square-wave jerks (SWJ) are the most common saccadic intrusion which can be readily seen at the bedside and also quantified using oculographic techniques. Various neurological, neuropsychiatric and psychiatric disorders display abnormal fixational eye movement patterns characterized by frequent SWJ. For the clinician, SWJ are particularly important because they can be readily observed at the bedside. Here, we will discuss the pathological conditions that present with SWJ and explore the expanding body of literature suggesting that SWJ may serve as a potential indicator for various clinical conditions.

Encephalitis in a patient with hypopharynx cancer treated with immune checkpoint inhibitors and radiotherapy: a case report and review of the literature

Hypopharyngeal cancer (HPC) has one of the most unfavorable prognoses among head and neck squamous cell carcinomas. Immunotherapy in combination with chemotherapy, the same as conventional induction chemotherapy, has emerged as a vital part of the induction therapy protocol for HPC. Meanwhile, the incidence of immune-related adverse events is increasing. In this light, we present the first reported case of immune-associated encephalitis in a patient with hypopharyngeal cancer treated with Camrelizumab (a PD-1 inhibitor). After receiving immunotherapy combined with chemotherapy as induction therapy, along with concurrent chemoradiotherapy, the patient presented with symptoms of fatigue, tremors, drowsiness, and an abnormal signal in the right temporal lobe as shown on a brain magnetic resonance imaging (MRI). Despite the minor elevation in protein and IgG index observed in the lumbar puncture, there is no evidence of abnormal autoantibodies or evidence of pathogenic infection. Following a thorough multidisciplinary consultation, the patient is suspected to be afflicted with immune-related autoimmune encephalitis. Intravenous methylprednisolone was prescribed as an empirical treatment at an initial dosage of 120 mg/day for 3 days, followed by steroid tapering. Finally, the patient experienced complete neurologic and radiographic (brain MRI) recovery. This case serves as a critical reminder that encephalitis is a potential diagnosis that should never be overlooked in patients undergoing immunotherapy who present with abnormal signs of the brain. The timely diagnosis and initiation of immunosuppressive therapy are key components of treating ICI-associated encephalitis.

Atezolizumab-induced subacute cerebellar ataxia in a patient with extensive-stage small cell lung cancer

Recently, immune checkpoint inhibitors (ICIs) have become the standard treatment option for patients with lung cancer, including small cell lung cancer (SCLC). ICI-induced neurological immune-related adverse events are rare and exhibit diverse clinical manifestations, often leading to missed or delayed diagnosis. Herein, we report the case of a patient with extensive-stage SCLC who received atezolizumab with etoposide/platinum and gradually developed neurological symptoms after three cycles of chemoimmunotherapy. Subsequently, the patient received a diagnosis of subacute immune-related cerebellar ataxia and was treated successfully with pulse steroid therapy. The patient exhibited almost complete remission of neurological symptoms and had progression-free survival for >24 months.

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.

Cerebellar involvement associated with immune checkpoint inhibitors: A systematic review

BACKGROUND AND PURPOSE

Immune checkpoint inhibitors (ICIs) targeting programmed death receptor 1 (PD-1), cytotoxic T-lymphocyte-associated-4 (CTLA-4) and programmed cell death ligand 1 can be associated with immune-related adverse events (iRAEs). Amongst neurological iRAEs, cerebellar involvement seems to be rare and currently lacks a proper characterization. The aim of this study was to phenotype cerebellar iRAEs.

METHODS

A systematic review was performed according to PRISMA guidelines including reported patients with cerebellar involvement related to ICIs and with available individual data.

RESULTS

After screening 2765 records, 32 studies with 46 patients were included. Median age was 63 years (20-82), and most patients were male (63.0%). Isolated cerebellitis was observed in 32.6% of cases, whilst the remaining cases had "cerebellitis plus", mostly associated with encephalitis/encephalopathy. Associated tumors included most frequently lung cancer, melanoma and Merkel cell carcinoma. PD-1 inhibitor was the most administered treatment (n = 29, 64.4%), whilst exposure to CTLA-4 inhibitor was rare (n = 2, 4.5%). Magnetic resonance imaging was abnormal in 43.2% of patients and inflammatory cerebrospinal fluid findings were frequently observed. Autoantibodies were detected in 61.9% of patients and included novel reactivities. Amongst treatment strategies, the most common were steroids (n = 36) and ICI discontinuation (n = 28, 90.3%). Relapses were reported in 10% of patients. Most patients showed improvement/remission (n = 31) but, at last follow-up, 12 had died. Isolated cerebellitis versus cerebellitis-plus differed in terms of outcomes, whilst seropositive versus seronegative patients had distinct tumor associations.

DISCUSSION

Cerebellar iRAEs are usually multifocal, have heterogeneous tumor associations, are most associated with PD-1 inhibitor exposure and are related to autoantibodies, including novel reactivities.

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.

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.

Immune Checkpoint Inhibitor-Induced Cerebral Pseudoprogression: Patterns and Categorization

Background

The inclusion of immune checkpoint inhibitors (ICIs) in therapeutic algorithms has led to significant survival benefits in patients with various metastatic cancers. Concurrently, an increasing number of neurological immune related adverse events (IRAE) has been observed. In this retrospective analysis, we examine the ICI-induced incidence of cerebral pseudoprogression and propose a classification system.

Methods

We screened our hospital information system to identify patients with any in-house ICI treatment for any tumor disease during the years 2007-2019. All patients with cerebral MR imaging (cMRI) of sufficient diagnostic quality were included. cMRIs were retrospectively analyzed according to immunotherapy response assessment for neuro-oncology (iRANO) criteria.

Results

We identified 12 cases of cerebral pseudoprogression in 123 patients treated with ICIs and sufficient MRI. These patients were receiving ICI therapy for lung cancer (n=5), malignant melanoma (n=4), glioblastoma (n=1), hepatocellular carcinoma (n=1) or lymphoma (n=1) when cerebral pseudoprogression was detected. Median time from the start of ICI treatment to pseudoprogression was 5 months. All but one patient developed neurological symptoms. Three different patterns of cerebral pseudoprogression could be distinguished: new or increasing contrast-enhancing lesions, new or increasing T2 predominant lesions and cerebral vasculitis type pattern.

Conclusion

Cerebral pseudoprogression followed three distinct patterns and was detectable in 3.2% of all patients during ICI treatment and in 9.75% of the patients with sufficient brain imaging follow up. The fact that all but one of the affected patients developed neurological symptoms, which would be classified as progressive disease according to iRANO criteria, mandates vigilance in the diagnosis and treatment of ICI-induced cerebral lesions.

Pembrolizumab-Related Side Effects: Acute Renal Failure and Severe Neurological Toxicity

Immunotherapy with immune checkpoint inhibitors represents nowadays a marked improvement in cancer treatment. Nevertheless, they can cause severe toxicities that put the patient at high risk, often requiring aggressive treatment. We present the case of a female patient who developed a severe immune-related adverse reaction to Pembrolizumab prescribed for melanoma treatment. Her array of symptoms, which presented a few days after last drug administration, consisted of severe neurological deficit, severe renal failure, polymyositis, and hyperthyroidism. Treatment required the immediate interruption of the trigger drug, infusion of high dose steroids, renal replacement therapy, plasmapheresis, and methimazole, as will be further discussed.

CD8 T-cell-mediated cerebellitis directed against Purkinje cell antigen after ipilimumab for small cell lung cancer

We report a rapidly progressive and fatal CD8 T-cell-mediated cerebellitis after ipilimumab (cytotoxic T-lymphocyte-associated protein 4 inhibitor) for small cell lung cancer. Clinical features and histopathology were consistent with an accelerated form of paraneoplastic cerebellar degeneration. A patchy CD8 T-cell infiltrate spatially corresponded to areas of Purkinje cell loss, with occasional CD8 polarisation towards Purkinje cells. CD20-positive B cells were sparse. CD8 T-cell-mediated cerebellitis after immune checkpoint inhibitor treatment may recapitulate the early stages of paraneoplastic cerebellar degeneration.

A Review of Cancer Immunotherapy Toxicity: Immune Checkpoint Inhibitors

Cancer immunotherapy, which leverages features of the immune system to target neoplastic cells, has revolutionized the treatment of cancer. The use of these therapies has rapidly expanded in the past two decades. Immune checkpoint inhibitors represent one drug class within immunotherapy with its first agent FDA-approved in 2011. Immune checkpoint inhibitors act by disrupting inhibitory signals from neoplastic cells to immune effector cells, allowing activated T-cells to target these neoplastic cells. Unique adverse effects associated with immune checkpoint inhibitors are termed immune-related adverse effects (irAEs) and are usually immunostimulatory in nature. Almost all organ systems may be affected by irAEs including the dermatologic, gastrointestinal, pulmonary, endocrine, and cardiovascular systems. These effects range from mild to life-threatening, and their onset can be delayed several weeks or months. For mild irAEs, symptomatic care is usually sufficient. For higher grade irAEs, discontinuation of therapy and initiation of immunosuppressive therapy may be necessary. The management of patients with irAEs involves multidisciplinary care coordination with respect to the long-term goals the individual patient. Clinicians must be aware of the unique and sometimes fatal toxicologic profiles associated with immunotherapies to ensure prompt diagnosis and appropriate management.

Neurologic Adverse Events of Immune Checkpoint Inhibitors: A Systematic Review

OBJECTIVE

To define the clinical characteristics, management, and outcome of neurologic immune-related adverse events (n-irAEs) of immune checkpoint inhibitors (ICIs).

METHODS

Systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

A total of 694 articles were identified. Two hundred fifty-six articles, with 428 individual patients, met the inclusion criteria. Reports regarding neuromuscular disorders (319/428, 75%) were more frequent than those on CNS disorders (109/428, 25%). The most common n-irAEs reports were myositis (136/428, 32%), Guillain-Barré syndrome and other peripheral neuropathies (94/428, 22%), myasthenic syndromes (58/428, 14%), encephalitis (56/428, 13%), cranial neuropathies (31/428, 7%), meningitis (13/428, 3%), CNS demyelinating diseases (8/428, 2%), and myelitis (7/428, 2%). Other CNS disorders were detected in 25/428 (6%) patients. Compared with the whole sample, myasthenic syndromes were significantly more Ab positive (33/56, 59%; p < 0.001). Anti-programmed cell death protein 1/programmed cell death ligand 1 was more frequent in myasthenic syndromes (50/58, 86%; p = 0.005) and less common in meningitis (2/13, 15%; p < 0.001) and cranial neuropathies (13/31, 42%; p = 0.005). Anti-cytotoxic T-lymphocyte antigen-4 ICIs were more frequent in meningitis (8/13, 62%; p < 0.001) and less common in encephalitis (2/56, 4%; p = 0.009) and myositis (12/136, 9%; p = 0.01). Combination of different ICIs was more frequent in cranial neuropathies (12/31, 39%; p = 0.005). Melanoma was more frequent in patients with peripheral neuropathies (64/94, 68%; p = 0.003) and less common in encephalitis (19/56, 34%; p = 0.001). The highest mortality rate was reached in myasthenic syndromes (28%).

CONCLUSION

Considering the increasing use of ICI therapy in the forthcoming future, this information can be valuable in assisting neurologists and oncologists in early n-irAEs diagnosis and treatment.

Challenges of New Approaches in Metastatic Merkel Cell Carcinoma

Merkel cell carcinoma is a rare and aggressive cutaneous tumor, and the use of checkpoint inhibitors immunotherapy is a recent indication in its metastatic setting, both first and second line. However, the widespread use of immunotherapy is associated with an increase of acute and late immune-mediated adverse events. We present a case of an elderly fit patient with metastatic Merkel cell carcinoma treated with pembrolizumab who developed diabetic ketoacidosis, a severe immune-mediated adverse event. A multidisciplinary approach was crucial to overcome the life-threatening event. Even with early treatment stop, the patient had a significant and durable response to the treatment for 15 months. Meanwhile, a progressive pan-cerebellar syndrome emerged, possible due to a paraneoplastic syndrome with a negative onco-neuronal antibody panel, although an autoimmune etiology associated with immunotherapy could not be excluded. Unfortunately, the situation was irreversible and refractory to immunomodulatory treatment. Despite the unpredictable toxicity, it is important to note the efficacy profile, with a progression-free survival of 15 months, which is higher than the one reported in reference clinical trials in this setting.

Neurologic complications of immune checkpoint inhibitors

Introduction: Immune checkpoint inhibitors (ICI) are associated with a wide spectrum of neurologic immune-related adverse events (irAEs) including meningo-encephalitis, myasthenia gravis and various neuropathies. Although relatively rare, they often present significant diagnostic complexity and may be under-recognized. Permanent neurologic deficits and/or fatality have been described but improvement is noted in most cases with ICI discontinuation and immunosuppressive therapy.Areas covered: This review highlights the most frequently reported ICI-associated neurologic toxicities with a particular focus on those that may be more severe and/or fatal. Data from case series and pharmacovigilance studies is leveraged to provide an overview of associated clinical features, expected outcomes and appropriate management. Various immunobiologic triggers have been proposed to explain why certain patients might develop neurologic irAEs and are also briefly discussed.Expert opinion: All providers who care for patients with cancer should be made aware of common neurologic irAEs and able to recognize when prompt evaluation and consultation with appropriate specialists are indicated. Symptoms suggestive of encephalitis, myasthenia-gravis or an acute polyradiculopathy such as Guillain-Barre Syndrome (GBS) in patients exposed to these agents warrant immediate attention with a low threshold for hospitalization to expedite work-up and monitor for severe and/or life-threatening manifestations.

Neurologic Immune-Related Adverse Events Associated with Immune Checkpoint Inhibition

PURPOSE OF REVIEW

This review highlights the spectrum of neurologic adverse events seen with use of immune checkpoint inhibitors (ICIs), their potential mechanisms, the treatments undertaken, and the clinical outcomes.

RECENT FINDINGS

The advent of ICIs has revolutionized cancer therapy. Neurologic adverse events (NAEs) are rare but clinically significant complication of ICIs. They can involve both the central and peripheral nervous system. Examples include myositis, neuropathy, encephalopathy, and myasthenia gravis. Treatment consists of holding the ICI, administration of corticosteroids, and other immunomodulatory agents as needed. The outcomes are generally favorable; however, rarely severe events can lead to significant morbidity and even mortality. Identifying and treating the range of neurologic adverse events that may potentially arise with ICIs is very important as the oncologic indications for their use continues to expand.