Neurological toxicities associated with immune-checkpoint inhibitors

Neurologic Complications in Patients with Cancer

Neurologic symptoms are commonly seen in patients with cancer and can be among the most challenging to diagnose and manage. It is often difficult to determine if new neurologic symptoms are secondary to direct effects of a malignant lesion, systemic complications of disease, paraneoplastic disorders, or side effects of cancer treatment itself. However, early diagnosis and treatment of each of these conditions can improve patients' quality of life and long-term functional outcomes. In this review, we describe a systematic approach to the diagnosis of new neurologic symptoms in patients with known malignancy. We have categorized the neurologic complications of cancer through a mechanistic approach, with an emphasis on ascertaining underlying pathophysiology to guide treatment choice. This review focuses on the acute neurologic complications of cancer that require hospital admission.

Central Nervous System Complications Among Oncology Patients

Cancer treatment related injury to the central nervous system (CNS) is well-recognized in the setting of brain-directed radiation therapies and conventional and novel systemic anticancer therapies. Late-delayed treatment-induced CNS complications frequently result in permanent neurologic disability. Therapeutic options are supportive with limited clinical benefit, whereby alteration or discontinuation of the overall antineoplastic treatment plan is frequently necessary to prevent further neurologic injury. Better identification of patients at high risk for developing late CNS toxicities, neuroprotective strategies with modification of existing antineoplastic treatment regimens, and research efforts directed at earlier recognition and improved treatment of central neurologic complications are paramount.

[An Unusual Cause for a Bilateral Ptosis]

An Unusual Cause for a Bilateral Ptosis Abstract. Immune-checkpoint-inhibitors are increasingly used in various malignancies. Autoimmune side effects such as colitis, hepatitis or skin reactions are well known, on the other hand neurological autoimmune complications such as myasthenic syndromes, myopathies or overlap syndromes with potentially life-threatening complications are less common and not well understood. A precise diagnosis has far reaching therapeutic consequences. Here we present the case of a patient under immune checkpoint inhibitor therapy, in which the diagnosis, due to the presence of overlap symptoms, is shown to be challenging. However, it was crucial to find the correct diagnosis in order to choose the proper therapy.

Guillain-Barré Syndrome-Like Polyneuropathy Associated with Immune Checkpoint Inhibitors: A Systematic Review of 33 Cases

Immune checkpoint inhibitors (ICIs) have been increasingly used in the treatment of various types of tumors with favorable results. But these treatments also led to a variety of immune-related adverse events (irAEs). Neurological irAEs such as Guillain-Barré Syndrome are rare and may have serious consequences once they occur. A systematic literature search was performed in PubMed and Embase for all case reports of GBS associated with ICIs published in English reporting on human beings from 1990 up to date. A total of 30 case reports (total patients = 33) were used for final analysis. The included cases were from 11 countries, covering 10 tumor types, with melanoma accounting for the largest number. The mean age was 62.2 ± 11.1 years old, and males were dominant (male: 26 and female: 7). The median time of initial symptoms was 8.2 weeks after the 1^st dose of ICIs. The most common manifestations of GBS associated with ICIs were weakness, hyporeflexia or areflexia, and paresthesia in order. The GBS subtypes suggested by electrophysiological results were acute inflammatory demyelinating polyneuropathy (AIDP), acute motor axonal neuropathy (AMAN), and Miller Fisher syndrome (MFS). The protein level of CSF in patients with GBS related to ICIs was 180.68 ± 152.51 mg/dl. Immediate termination of ICIs followed by intravenous immunoglobulin was the preferred treatment option. 72.7% of patients recovered or had residual mild dysfunction after treatment. Elderly male patients with melanoma were most likely to develop ICI-related GBS. The specific neurological symptoms, CSF analysis, and electrophysiological examination were important means of diagnosis.

Characterization and management of neurological adverse events during immune-checkpoint inhibitors treatment: an Italian multicentric experience

BACKGROUND

Neurological immune-related adverse events (nirAEs) are rare toxicities of immune-checkpoint inhibitors (ICI). With the increase of ICI oncological indications, their incidence is growing. Their recognition and management remain nevertheless challenging.

METHODS

A national, web-based database was built to collect cases of neurological symptoms in patients receiving ICI and not attributable to other causes after an adequate workup.

RESULTS

We identified 27 patients who developed nirAEs (20 males, median age 69 years). Patients received anti-PD1/PDL1 (78%), anti-CTLA4 (4%), or both (19%). Most common cancers were melanoma (30%) and non-small cell lung cancer (26%). Peripheral nervous system was mostly affected (78%). Median time to onset was 43.5 days and was shorter for peripheral versus central nervous system toxicities (36 versus 144.5 days, p = 0.045). Common manifestations were myositis (33%), inflammatory polyradiculoneuropathies (33%), and myasthenia gravis (19%), alone or in combination, but the spectrum of diagnoses was broad. Most patients received first-line glucocorticoids (85%) or IVIg (15%). Seven patients (26%) needed second-line treatments. At last follow-up, four (15%) patients were deceased (encephalitis, 1; myositis/myasthenia with concomitant myocarditis, 2; acute polyradiculoneuropathy, 1), while seven (26%) had a complete remission, eight (30%) partial improvement, and six (22%) stable/progressing symptoms. ICI treatment was discontinued in most patients (78%).

CONCLUSIONS

Neurological irAEs are rare but potentially fatal. They primarily affect neuromuscular structures but encompass a broad range of presentations. A prompt recognition is mandatory to timely withheld immunotherapy and administrate glucocorticoids. In corticoresistant or severely affected patients, second-line treatments with IVIg or plasmapheresis may result in additional benefit.

Myositis and myasteniform syndrome related to pembrolizumab

This case report concerns a 63-year-old man affected by metastatic undifferentiated liposarcoma. After receiving pembrolizumab as a second-line treatment in a clinical trial, the patient experienced an immune-mediated myocarditis, myositis and myasteniform syndrome. The last two adverse events showed significant clinical relevance in terms of severity, duration and the required specific treatment.Initial treatment approach consisted in pulses of 1 g of methylprednisolone, followed by 2 mg/kg/day, with clinical improvement. After 12 days, the immune-mediated myasteniform syndrome worsened, with dysphagia, dysphonia, bilateral palpebral ptosis and respiratory difficulty. Due to the refractoriness to glucocorticoid treatment, it was decided to initiate intravenous immunoglobulin at 2 g/kg, followed by 2 mg/kg every 4 weeks once discharged and mycophenolate 500 mg/12 hours, in order to reduce the dose of glucocorticoids.After 2 months, the patient presented an optimal clinical evolution, without muscular weakness and referred to an improvement in dysphagia and speech.

PD-1-inhibitor-induced PCA-2 (MAP1B) Autoimmunity in a Patient with Renal Cell Carcinoma

Immune check point inhibitors (ICIs) are a group of anti-cancer pharmacological agents which modify T cell activity in order to potentiate an effective immune response against tumor cells. While these drugs prove extremely potent against several types of malignancies, they may be associated with significant autoimmune adverse events. We report a patient who developed a subacute cerebellar syndrome shortly after starting treatment with nivolumab, a PD-1 inhibitor, for renal clear cell carcinoma, with detectable paraneoplastic PCA-2 antibodies. The tumor specimen stained positively for MAP1B, the antigen of PCA-2. The patient responded well to treatment with glucocorticosteroids. This is the first case to our knowledge of PCA-2 paraneoplastic cerebellar degeneration associated with ICI use, which presents in a patient with a malignancy not typically associated with neurological paraneoplastic phenomena. Treatment with immune checkpoint inhibitors (ICIs) is extremely effective in potentiating an immune response against tumor cells, but bears a substantial risk for the development of autoimmune phenomena, including paraneoplastic neurological syndromes. Increasing use of ICIs is leading to increasing numbers of patients with new-onset neurological symptoms. Awareness of these novel entities will aid in early diagnosis and proper treatment.

Neuromuscular complications of cancer therapy

PURPOSE OF THE REVIEW

The neuromuscular complications of cancer therapy include chemotherapy-induced peripheral neurotoxicity (CIPN), immune-related neuromuscular complications to immune checkpoint inhibitors and radiation-induced neuropathy/plexopathy. With a wider focus on CIPN, we will discuss new pathogenetic insights, recent predictive biomarkers and emerging therapies for neuromuscular complications of cancer therapy.

RECENT FINDINGS

Findings from recent preclinical studies have improved our knowledge on new CIPN pathogenetic pathways, including the activation of senescence-like processes in neurons, axonal degeneration and neuroinflammation. Metabolomics and serum neurofilament light chain levels appear the most promising biomarkers to predict CIPN development and severity. There is some recent evidence of promising pharmacological compounds to prevent or treat CIPN, and new drugs are in early development and testing.

SUMMARY

A multimodal assessment, with neurophysiological, imaging and patient-reported outcome measures, coupled with the use of reliable blood or genetic biomarkers, may offer pathogenetic grounds for future preventive and symptomatic strategies for the multidisciplinary treatment of neuromuscular complications of cancer therapy.

Inflammatory markers in autoimmunity induced by checkpoint inhibitors

PURPOSE

Immune checkpoint inhibitors (ICI) are highly effective in several cancer entities, but also invoke a variety of immune-related adverse events (irAE). These are mostly reversible, but can be life-threatening or even fatal. Currently, the pathogenesis is not fully understood, but crucial for effective treatment. Prediction and early detection of irAE could be facilitated and treatment optimized if relevant biomarkers and effector mechanisms were better characterized.

METHODS

This study included a total of 45 irAE in patients with metastatic melanoma who were treated with ICI. All patients underwent a complete work-up with exclusion of other causes. Longitudinal blood samples were analyzed for a panel of soluble markers and compared to baseline and to patients who did not experience any irAE. Measurements included LDH, interleukin (IL)-6, IL-1β, IL-17, C-reactive protein (CRP) and tumor necrosis factor (TNF)-alpha as well as tumor markers S100 and melanoma inhibitory activity (MIA).

RESULTS

During the early onset of irAE increases in serum IL-6 (from mean 24.4 pg/ml at baseline to 51.0 pg/ml; p = 0.003) and CRP (from mean 7.0 mg/l at baseline to 17.7 mg/l; p = 0.001) and a decrease in MIA (from mean 5.4 pg/ml at baseline to 4.8 pg/ml; p = 0.035) were detected. No changes in IL-17 were noted. These effects were observed for irAE of different organ systems.

CONCLUSION

Increases of a combination of IL-6 and CRP serum levels can be used for the early detection of irAE and tailored management. Interestingly, changes in MIA serum levels also correlate with irAE onset.

Managing side effects of immune checkpoint inhibitors in breast cancer

Immune-checkpoint inhibitors (ICIs) represent a major development in cancer therapy. The indications for these agents continue to expand across malignancies and disease settings. For years breast cancer (BC) has been considered immunologically quiescent compared with other tumor types. However, recent findings highlighted the immunogenicity of some BCs and paved the way for clinical trials of immunotherapy in BC that led to recent landmark approvals. As a drawback, the safety profile of ICIs is shaped by a specific spectrum of immune-related adverse events (irAEs) that can vary according to ICI class and tumor histology. This review will discuss the epidemiology of these adverse events, their kinetics, risk factors and the most important aspects in their management. A particular focus will be put on BC as the current landscape of immunotherapy for this disease is rapidly increasing the number of people treated with ICIs, thus susceptible to irAEs.

GAD65 autoimmunity after treatment with nivolumab: a multifocal presentation

INTRODUCTION

Neurological disorders are considered rare complications of immune-checkpoint inhibitor.

CASE DESCRIPTION

We report a 63-year-old man with recurrence of melanoma who presented epilepsy, limbic encephalitis, cerebellar ataxia, and stiff person syndrome soon after treatment with nivolumab, an immune-checkpoint inhibitor. On autoimmune screening, serum and CSF GAD65 were detected. Significant response to steroids and intravenous immunoglobulins were observed, but cancer recurred after nivolumab discontinuation in parallel with epileptic seizure and worsening of cognitive impairment and the patient died.

DISCUSSION

This case expands the spectrum of GAD65-associated conditions induced by immune-checkpoint inhibitor and underlines treatment complexity when both neurological complications and tumour recurrence occur.

Longitudinally Extensive Myelitis Associated With Immune Checkpoint Inhibitors

OBJECTIVE

To define the characteristics and the outcome of myelitis associated with immune checkpoint inhibitors (ICIs).

METHODS

We performed a retrospective research in the databases of the French Pharmacovigilance Agency and the OncoNeuroTox network for patients who developed myelitis following treatment with ICIs (2011-2020). A systematic review of the literature was performed to identify similar cases.

RESULTS

We identified 7 patients who developed myelitis after treatment with ICIs (anti-PD1 [n = 6], anti-PD1 + anti-CTLA4 [n = 1]). Neurologic symptoms included paraparesis (100%), sphincter dysfunction (86%), tactile/thermic sensory disturbances (71%), and proprioceptive ataxia (43%). At the peak of symptom severity, all patients were nonambulatory. MRI typically showed longitudinally extensive lesions, with patchy contrast enhancement. CSF invariably showed inflammatory findings. Five patients (71%) had clinical and/or paraclinical evidence of concomitant cerebral, meningeal, caudal roots, and/or peripheral nerve involvement. Despite the prompt discontinuation of ICIs and administration of high-dose glucocorticoids (n = 7), most patients needed second-line immune therapies (n = 5) because of poor recovery or early relapses. At last follow-up, only 3 patients had regained an ambulatory status (43%). Literature review identified 13 previously reported cases, showing similar clinical and paraclinical features. All patients discontinued ICIs and received high-dose glucocorticoids, with the addition of other immune therapies in 8. Clinical improvement was reported for 10 patients.

CONCLUSION

Myelitis is a rare but severe complication of ICIs that shows limited response to glucocorticoids. Considering the poor functional outcome associated with longitudinally extensive myelitis, strong and protracted immune therapy combinations are probably needed upfront to improve patient outcome and prevent early relapses.

A systematic review of immune checkpoint inhibitor-related neurological adverse events and association with anti-neuronal autoantibodies

Introduction: Immune checkpoint inhibitors (ICI) therapy has led to a paradigm shift in cancer drug development and in the clinical evaluation of approaches to combination cancer treatment. Dysregulation of the immune system by ICI therapy may also elicit autoimmune phenomena and consequently manifest clinically as immune-related adverse events (irAEs) including neurological irAEs. Areas Covered: The purpose of this review is to explore the role of autoantibodies in the diagnosis and prediction of neurological irAEs and to evaluate their pathogenicity. We searched Pubmed and Embase for neurological irAEs and associated autoantibodies and found 28 patients with central and peripheral neurological irAEs. Of these patients, up to 40% had encephalitis, 34.4% with myasthenia gravis and 22% of patients with peripheral neuropathy and Guillain-Barre Syndrome had autoantibodies. Expert Opinion: Overall, our survey suggested a causal relationship between neurological irAEs and autoantibodies. Detection of autoantibodies may help to diagnose neurological irAEs and inform their clinical management.

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.

How can we manage the cardiac toxicity of immune checkpoint inhibitors?

Introduction: Cancer immunotherapies with monoclonal antibodies (mAbs) against immune checkpoints (i.e. CTLA-4 and PD-1/PD-L1) have revolutionized antineoplastic treatments. Immune checkpoint inhibitors (ICIs) approved for cancer immunotherapy are mAbs anti-CTLA-4 (ipilimumab), anti-PD-1 (nivolumab, pembrolizumab, and cemiplimab), and anti-PD-L1 (atezolizumab, avelumab, and durvalumab). Treatment with ICIs can be associated with immune-related adverse events (irAEs), including an increased risk of developing myocarditis. These findings are compatible with the observation that, CTLA-4, PD-1, and PD-L1 pathways play a central role in the modulation of autoimmunity.Areas covered: In this paper, we start from examining the pathogenesis of cardiovascular adverse events from ICIs, and then we focus on risk factors and strategies to prevent and manage this cardiotoxicity.Expert opinion: There is a growing need for a multidisciplinary approach of ICI-associated cardiotoxicity, involving oncologists, cardiologists, and immunologists. Prevention and effective management of ICIs cardiotoxicity starts with an in-depth screening and surveillance strategies of high-risk patients, in order to improve early detection and appropriate management in a personalized approach.

Immune Checkpoint Inhibitor-induced Bilateral Vestibulopathy

Checkpoint inhibitors (CPI), such as anti-programmed death-1 and anti-cytotoxic T-lymphocyte antigen-4antibodies cause serious, rarely fatal immune-related adverse events (irAE) potentially in all organ systems. Neurological immune-related adverse events occur in 1%-5% of patients on CPI therapy and may present with dramatic clinical symptoms of the sensory organs. After exclusion of other causes, a high-dose treatment with corticosteroids is crucial for clinical outcome with lower risk of sequelae. We present a severe case of CPI-related ongoing and most likely irreversible bilateral vestibular affection. A 59-year-old male melanoma patient with brain metastasis undergoing immunotherapy with anti-cytotoxic T-lymphocyte antigen-4 and anti-programmed death-1 antibodies developed severe debilitating rotatory vertigo. Bilateral vestibulopathy was diagnosed as a result of the CPI therapy after a thorough analysis including magnetic resonance imaging, laboratory tests of blood and cerebrospinal fluid as well as neurological and otorhinolaryngology examinations. The vertigo improved slightly during a 10-day course of steroid therapy and intensive balance training but did not resolve completely.

Neurological complications of immune checkpoint inhibitor cancer immunotherapy

Neurological autoimmunity is increasingly recognized as a complication of immune checkpoint inhibitor (ICI) cancer immunotherapy. ICIs act by enhancing endogenous anti-tumor immune responses and can also lead to autoimmunity affecting all organs. ICI-related neurological autoimmunity is rare, most often manifests with neuromuscular involvement and more rarely affects the central nervous system. Neurological complications often often present in the first three months of ICI treatment but can also appear after ICI discontinuation. These can occur in patients with tumors not traditionally associated with paraneoplastic neurological autoimmunity, such as melanoma and renal-cell carcinoma and should be suspected when a new neurological symptoms present while on ICI and cannot be explained by disease progression or as a consequence of metabolic dysfunction. Treatment consists of ICI discontinuation or withdrawal depending on the severity with or without immunosuppression. Generally, improvement is observed depending on the patient's baseline characteristics and neurological presentation.

Myositis and myasthenia during nivolumab administration for advanced lung cancer: a case report and review of the literature

The immunotherapy significantly improved survival of non-small cell lung cancer patients, but it may cause immune-related adverse events, which are severe in less than 10% of cases. We report the case of one patient who developed myositis and myasthenia during nivolumab treatment for metastatic lung squamous carcinoma. Moreover, we reviewed literature data in order to identify similar cases in cancer patients treated with immune-checkpoints inhibitors. A 65-year-old patient, who had previously received a first-line platinum-based therapy, developed diplopia and ptosis 4 weeks after the start of nivolumab. Although antibodies associated with myositis, myasthenia gravis and paraneoplastic syndromes were absent, immune-related myositis and myasthenia were diagnosed. Corticosteroids, immunoglobulin and pyridostigmine showed poor efficacy and the patient died 7 weeks after the appearance of the first symptoms. Fifteen similar cases were found in the literature. A close collaboration between different specialists is essential to rapidly identify and treat severe immune-related adverse events.

Neurological complications of chimeric antigen receptor T cells and immune-checkpoint inhibitors: ongoing challenges in daily practice

PURPOSE OF REVIEW

The aim of this review is to summarize the most recent advances in the management of neurological toxicities associated with immune-checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR)-T cells.

RECENT FINDINGS

The advent of cancer immunotherapies has dramatically improved the prognosis of several refractory and advanced neoplasms. Owing to their mechanism of action, cancer immunotherapies have been associated with a variety of immune-related adverse events (irAE). Neurological irAE are uncommon compared with other irAE, but they are associated with significant morbidity and mortality. Despite the efforts to draft common protocols and guidelines, the management of neurological irAE remains challenging. Our ability to predict the development of neurotoxicity is still limited, hampering to elaborate prevention strategies. Treatment heavily relies on the administration of high-dose corticosteroids that, however, have the potential to impair oncological efficacy. The experimentation of novel strategies to avoid resorting to corticosteroids is hindered by the lack of an adequate understanding of the pathogenetic mechanisms driving the development of irAE.

SUMMARY

In this review, we will discuss the most recent advances on the diagnosis and management of neurological irAE associated with ICIs and CAR-T cells, focusing on the issues that remain most challenging in clinical practice.

Clinical and biochemical markers in CIPN: A reappraisal

The increased survival of cancer patients has raised growing public health concern on associated long-term consequences of antineoplastic treatment. Chemotherapy-induced peripheral neuropathy (CIPN) is a primarily sensory polyneuropathy, which may be accompanied by pain, autonomic disturbances, and motor deficit. About 70% of treated cancer patients might develop CIPN during or after the completion of chemotherapy, and in most of them such complication persists after six months from the treatment. The definition of the potential risk of development and resolution of CIPN according to a clinical and biochemical profile would be certainly fundamental to tailor chemotherapy regimen and dosage on individual susceptibility. In recent years, patient-reported and clinician-related tools along with quality of life instruments have been featured as primary outcomes in clinical setting and randomized trials. New studies on metabolomics markers are further pursuing accurate and easily accessible indicators of peripheral nerve damage. The aim of this review is to outline the strengths and pitfalls of current knowledge on CIPN, and to provide a framework for future potential developments of standardized protocols involving clinical and biochemical markers for CIPN assessment and monitoring.

Detect it so you can treat it: A case series and proposed checklist to detect neurotoxicity in checkpoint therapy

Background

Checkpoint inhibitors show impressive and durable responses in various cancer types and provide new avenues for cancer immunotherapy. However, these drugs have a variety of adverse events. Common autoimmune-related adverse effects include fatigue, hepatitis, skin rash, endocrine deficiencies, and colitis. Neurotoxicity has been reported, but its incidence and course remain unclear.

Methods

To illustrate the broad spectrum of neurotoxicity, we exemplarily report the neurological adverse events of five patients with melanoma and one patient with differentiated thyroid cancer who received checkpoint inhibitors at Essen University Hospital (Essen, Germany).

Results

After treatment with ipilimumab, nivolumab or pembrolizumab, neurotoxic effects included hypophysitis-associated neck pain and headache, Guillain-Barré syndrome, transverse myelitis, acute brachial plexus neuritis, and ocular myasthenia gravis.

Conclusions

Checkpoint inhibitor therapy remains a success story; however, neurological immune-related adverse events may cause severe life-threatening conditions. We propose a guide for the early detection of neurological adverse events during routine clinical treatment to prevent more severe courses of checkpoint inhibitor-induced neurotoxicity.

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We present neurological immune-related adverse events under checkpoint-inhibitors to underline the spectrums of manifestations.

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Neurological immune-related adverse events may cause severe life-threatening conditions.

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Practitioners should be aware of red flags symptoms to detect neurological immune-related adverse events

[Management of immune-related toxicities associated with immune checkpoints inhibitors: Data from the multidisciplinary meeting « ToxImmun » in Eastern Occitania]

Immune checkpoint inhibitors (ICIs) can cause numerous and complex immune-related adverse events whose management need a multidisciplinary approach. Herein, we investigated 114 requests, mostly concerning patients suffering from lung cancer, that were submitted to the « ToxImmun » multidisciplinary meeting in Eastern Occitania between December the 17th 2018 and January the 20th 2020. The leading reasons for the request concerned the putative causal link between immunotherapy and immune-toxicity and its management, followed by possible retreatment after temporary withdrawn because of adverse event, and finally the possibility to initiate ICIs in patients with pre-existing autoimmunity. Colitis, hepatitis and myocarditis were the most frequent immune-related adverse events (IRAEs), both all grade and grade 3-4. Sicca syndrome (with or without Sjogren criteria) was also frequent (26% of cases) and seems to be associated with severe toxicity and multi-toxicity. The mean time to first IRAE was 3.8 months, a time shortened with the use of anti-PD-L1 agents or ICI combination. A majority of requests came from initial evaluation by the internist confirming the early and main role of this specialty in the management of immunotoxicity. Expansion of this regional multidisciplinary meeting, coordinated by internists and medical oncologists, could improve management of immune-related adverse events for the patients' benefits.

Guillain-Barré syndrome in patients treated with immune checkpoint inhibitors

OBJECTIVE

Guillain-Barré syndrome (GBS) induced by immune checkpoint inhibitors (ICIs) has been occasionally reported in randomized clinical trials (RCTs), but the post-marketing data are quite limited. This study aimed to comprehensively examine GBS events secondary to ICI treatments in the real-world patients based on the Food and Drug Administration Adverse Event Reporting System (FAERS).

METHODS

Reports from January 2004 to March 2020 were extracted from the FAERS. GBS cases related to ICIs were identified to characterize their clinical features. The disproportionality and Bayesian analysis were performed for the detection of GBS signals associated with ICIs.

RESULTS

In total, 149 GBS reports with ICIs as suspect drugs were screened out. These events were found to be more prevalent in adults ≥ 45 years (63.09%) and males (63.09%). The onsets of GBS were variable with a median time of 38 (range 0-628) days after ICI initiation. The outcomes tended to be severe with 61.74% hospitalization and 22.82% death. GBS events were most commonly reported in ipilimumab plus nivolumab treatment (24.83%), and this combination therapy also yielded stronger signal for GBS than other therapies based on the highest reporting odds ratio (ROR = 12.43, two-sided 95% CI = 8.62, 17.93), proportional reporting ratio (PRR = 12.39, χ² = 300.90), information component (IC = 3.62, IC025 = 2.51) and empirical Bayes geometric mean (EBGM = 12.28, EBGM05 = 9.04).

CONCLUSION

As complements to the safety data from RCTs, the current pharmacovigilance research helps establish a more detailed overview of ICI-related GBS, which facilitates the understanding of this rare adverse drug effect.

Neurotoxicities associated with immune checkpoint inhibitor therapy

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have emerged as a promising class of cancer immunotherapies. Neurotoxicities are uncommon, but often severe, and potentially fatal complications of ICIs, and clinical experience is limited. The aim of this study is to further define the clinical spectrum and outcome of ICI-mediated neurotoxicities.

METHODS

Patients with ICI-associated neurotoxicities were identified from retrospective review of the quality control database at a single institution. Data regarding demographics, medical history, clinical presentation, diagnosis, management and outcome were recorded.

RESULTS

We identified 18 patients with neurotoxicity following ICI therapy with pembrolizumab, nivolumab, atezolizumab, or ipilimumab for a diverse set of malignancies. Neurotoxicities comprised central demyelinating disorder (28%), autoimmune encephalitis predominantly affecting the grey matter (17%), aseptic meningitis (6%), myasthenia gravis (MG) (17%) with concurrent myositis (6%), sensorimotor polyneuropathy (11%) and hypophysitis (17%). Median time to onset of neurotoxicities was 5 weeks (range 1-72). All patients discontinued ICIs and received steroids with additional immunomodulation required in 9 patients, resulting in improvement for 16 of 18 patients. Grade 3-4 neurotoxicity developed in 14 patients, of whom 6 had died at database closure. Grade 3-4 severity negatively impacted overall survival (OS) (p = 0.046).

CONCLUSIONS

ICI-mediated neurotoxicities present early, are rapidly progressive and include a diverse phenotype affecting the CNS, PNS and neuroendocrine system. A high level of vigilance is warranted, as early diagnosis and targeted treatment can substantially prevent morbidity and mortality. Prospective clinical trials are warranted to assess optimized management of ICI-induced neurotoxicities.

Immune Checkpoint Inhibitors and Neurotoxicity

Immune checkpoint inhibitors (ICIs) have recently been used as a promising treatment for cancer, while their toxicity and immune-related side effects can be seen in any organ, including the nervous system. In contrast to other immune-related adverse events (irAEs), neurological irAEs (nAEs) are rare, with varying incidence and symptom complexity. Although nAEs are uncommon, they can sometimes be severe and even lead to death. However, little attention has been paid to nAEs, and the literature is mostly clinical reports with only a few cases. We, therefore, conducted the present review with the aim of providing a comprehensive introduction of nAEs. In this review, we summarized various nAEs, including meningitis, encephalitis, and hypophysitis in the central nervous system, and myositis, myasthenia gravis, and peripheral neuropathies in the peripheral system. We also reviewed the current diagnosis and treatment methods for nAEs commonly used in clinical practice. In addition, we discussed potential mechanisms regarding nAEs and proposed the possible approaches to prevent the risk of nAEs in patients treated with ICIs. There is still a lot to learn, such as whether and why patients with nAEs respond better to ICI-therapy. The mechanisms and significance of nAEs need to be fully clarified to address these issues and optimize the treatment strategy.

Toxicities from immunotherapy: From clinical trials to real-world clinical practice

In recent years, immunotherapy has become an important pillar of cancer treatment, with high response rates regardless of tumour histology or baseline mutations. However, immune activation associated with check-point inhibitors is not selective and a large variety of immune-related adverse events have been associated with anti-PD1, anti-PD-1/L-1 and anti-CTLA-4 agents. Though diagnosis and treatment of these toxicities have been established according to the recommendations from clinical trials and in line with the autoimmune disorders that they mimic, increasing real-world data is coming up showing that these adverse events may have differential characteristics and management, especially in terms of the use of corticoids, second-line treatments, salvage therapy for life-threatening cases and reintroduction of immunotherapy. Herein we present a comprehensive review of current recommendations and real-world data on the main immune-related adverse events of immunotherapy.

Immune-Related Neurological Toxicities of PD-1/PD-L1 Inhibitors in Cancer Patients: A Systematic Review and Meta-Analysis

Background

Systematic assessment of PD-1/PD-L1 inhibitor-related neurological toxicities is important for guiding anti-PD-1 and anti-PD-L1 immunotherapy. Therefore, we conducted this meta-analysis to reveal the relationship between PD-1/PD-L1 inhibitors and neurological toxicities among cancer patients.

Methods

Clinical trials investigating PD-1/PD-L1 inhibitors in cancer patients were identified by a systematic search of PubMed. The random-effect model was used to synthesize individual studies. Neurological toxicities, including all-grades and grades 3–5, were taken into account for the final comprehensive meta-analysis. The Newcastle Ottawa Scale (NOS) was used to assess the quality of included trials.

Results

Thirty-one clinical trials containing data of neurological toxicities were included. Compared with chemotherapy, the risk of all-grade neurological toxicities caused by PD-1/PD-L1 inhibitors was much lower in terms of peripheral neuropathy [OR = 0.07, 95%CI:(0.04, 0.13)], peripheral sensory neuropathy [OR = 0.07, 95%CI(0.04, 0.12)], dysgeusia [OR = 0.26, 95%CI:(0.19, 0.35)], paraesthesia [OR = 0.23, 95%CI:(0.14, 0.36)], and polyneuropathy [OR = 0.12, 95%CI:(0.01, 0.94)]. However, for grades 3–5, the statistically significant results were only seen in peripheral neuropathy [OR = 0.15, 95%CI:(0.07, 0.34)] and peripheral sensory neuropathy [OR = 0.13, 95%CI:(0.04, 0.40)]. No statistically significant difference regarding the risk of headache, dizziness, and Guillain–Barré syndrome was found between PD-1/PD-L1 inhibitors and chemotherapy. For PD-1/PD-L1 inhibitors plus chemotherapy, the risk trends of the above-mentioned neurological toxicities, especially grades 3–5 peripheral neuropathy [OR = 1.76, 95%CI:(1.10, 2.82)] was increased compared to chemotherapy alone.

Conclusion

Our comprehensive analysis showed that PD-1/PD-L1 inhibitors alone exhibited lower neurological toxicities than chemotherapy. However, the risk of headache, dizziness, and Guillain–Barré syndrome was similar between PD-1/PD-L1 and chemotherapy. For PD-1/PD-L1 inhibitors plus chemotherapy, the incidence trend of neurological toxicities would be increased, especially for peripheral neuropathy of grades 3–5.

To treat or not to treat? Managing comorbidities in cancer patients under immune checkpoint inhibition

Objectives: Assessing the safety and efficacy of immune checkpoint inhibition in risky cancer patient subgroups: pre-existing organ failure, elderly, presence of auto-immune disease, transplanted patients and brain metastasis treated with immune checkpoint inhibitors. Methods: PubMed, Web of Science and Google scholar databases were searched for English articles published prior to February 2019. Search terms used were organ failure, dialysis, elderly, organ transplant, liver disease, auto-immune disease, immunosuppression, and brain metastasis. Results: Our literature data indicate that immune checkpoint inhibition in the majority of these subpopulations can be administered safely without any loss of efficacy. These data are mostly based on case-reports as only a minority of high-risk patients were included in (the earliest) clinical trials. Validation of these results is necessary on a larger scale. Conclusion: Future trials should not automatically exclude aforementioned patient groups but alter the study design and make their inclusion possible, since more data are needed to answer several remaining questions in these populations. Especially since ICI appears to be safe to administer in these patients.

Diagnosis and management of immune-related adverse effects of immune checkpoint therapy in the emergency department

Rapid advances in cancer immunotherapy using immune checkpoint inhibitors have led to significantly improved survival. Rapid identification of the toxicity syndromes associated with these therapeutic agents is very important for emergency physicians because the population of patients diagnosed with cancer is increasing and cancer therapies including immune checkpoint inhibitors have become the first-line treatment for more and more types of cancer. The emergency medicine literature lags behind rapid advances in oncology, and oncology guidelines for rapid recognition and management of these emerging toxicity syndromes are not familiar to emergency physicians. In this review article, we discuss the clinical presentation and management of immune-related adverse effects during the critical first hours of emergency care. We also suggest a workflow for the recognition and treatment of emergencies arising from serious immune-related adverse effects, including but not limited to colitis, adrenal crisis, myocarditis, pneumonitis, myasthenic crisis, diabetic ketoacidosis, bullous pemphigus, and hemophagocytic lymphohistiocytosis. Rapid advances in cancer therapy are bringing new diagnostic and therapeutic challenges to emergency providers, and therefore it is crucial to raise awareness and provide guidelines for the management of new treatment-related toxicities.

Potential Effect of Immunotherapy Agents on Cognitive Function in Cancer Patients

A paradigm shift is occurring in cancer therapy, where instead of targeting tumor cells, immunotherapy agents (IA) target the immune system to overcome cancer tolerance and to stimulate an antitumor immune response. IA using immune checkpoint inhibitors (CPI) or chimeric antigen receptor T-cells have emerged as the most encouraging approaches to treat cancer patients. CPI are reported to induce moderate-to-severe neurologic immune-related adverse events in less than 1% of patients, whereas chimeric antigen receptor T-cell therapy is associated with frequent neurological toxicities that can be severe or even fatal. Cognitive difficulties have been described following chemotherapy and targeted therapy, but not specifically explored in patients receiving IA. The aim of this review is to establish a picture of the first published studies suggesting some biological and physiopathological effects of IA on cognitive functions among cancer patients. The first results originate from a preclinical study evaluating the role of CPI associated with peripheral radiation on cognitive dysfunction and the recent discovery of the central nervous lymphatic system allowing leukocytes to penetrate the central nervous system. Evaluating possible side effects of IA on cognitive function will be an important challenge for future clinical trials and for better understanding the underlying mechanisms through preclinical animal models.

Inflammatory Manifestations of Systemic Diseases in the Central Nervous System

PURPOSE OF REVIEW

This review presents the current recommended therapeutic interventions for inflammatory disease in the central nervous system (CNS) secondary to systemic diseases of immune dysregulation. Treatment recommendations for CNS inflammation associated with rheumatologic conditions, immune-related adverse effects from immune checkpoint inhibitors (ICIs), and demyelinating disease from tumor necrosis factor-α (anti-TNFs) are explored. Additional therapeutic options for inflammation related to postviral syndromes and genetic immunodeficiencies are also discussed.

RECENT FINDINGS

In addition to treatment of mild, moderate, and severe CNS rheumatologic disease as guided by the European League Against Rheumatism (EULAR), early consideration of rituximab for severe IgG4-related disease and induction with anti-TNF therapy for severe neurosarcoidosis should be considered. Although often not first line, treatment options for CNS inflammatory diseases based on disease mechanism are emerging, including tocilizumab for Behcet's disease, natalizumab for ICI associated autoimmune encephalitis, and abatacept for treatment of infiltrative disease secondary to CTLA-4 deficiency. Hematopoietic stem cell treatments represent highly efficacious but risky options for autoimmunity related to genetic immunodeficiency.

SUMMARY

While early high dose steroids remains first line therapy for most CNS inflammatory conditions, a rapidly expanding arsenal of immune targeted therapies offers clinicians tailored disease specific options for treatment.

Glial fibrillary acidic protein (GFAP) associated autoimmune meningoencephalitis in a patient receiving nivolumab

Immune checkpoint inhibitors (ICIs) represent a major development in cancer treatment, allowing for improved survival and disease control in an expanding number of cancer types. Due to their mechanism of disrupting immunologic homeostasis, ICIs are frequently associated with adverse effects, termed immune related adverse effects (irAE). These side effects can affect any organ system, including the central and peripheral nervous systems. We present a case of a 47 year old man with stage IIIc metastatic melanoma who received 3 cycles of nivolumab (a monoclonal antibody inhibitor of programmed cell death protein 1 (PD-1)). After completing the third cycle, he presented with a meningoencephalitis clinical picture with an inflammatory cerebrospinal fluid (CSF) and normal MRI. He was found to have a positive anti-glial fibrillary acidic protein (GFAP) autoantibody in his CSF by immunofluorescent assay (IFA) and cell based assay (CBA) which confirmed a diagnosis of anti-GFAP autoimmune encephalitis. He was treated with immunotherapy and made a full recovery. In this report, we present the first reported case of anti-GFAP autoimmune encephalitis associated with ICI therapy and provide a brief review of the literature.

Immune-related adverse events of checkpoint inhibitors

Cancer immunotherapies have changed the landscape of cancer treatment during the past few decades. Among them, immune checkpoint inhibitors, which target PD-1, PD-L1 and CTLA-4, are increasingly used for certain cancers; however, this increased use has resulted in increased reports of immune-related adverse events (irAEs). These irAEs are unique and are different to those of traditional cancer therapies, and typically have a delayed onset and prolonged duration. IrAEs can involve any organ or system. These effects are frequently low grade and are treatable and reversible; however, some adverse effects can be severe and lead to permanent disorders. Management is primarily based on corticosteroids and other immunomodulatory agents, which should be prescribed carefully to reduce the potential of short-term and long-term complications. Thoughtful management of irAEs is important in optimizing quality of life and long-term outcomes.

Immune Checkpoint Inhibitor-Related Myositis: From Biology to Bedside

Immune checkpoint inhibitor (ICI)-related inflammatory diseases, including polymyositis (PM) and dermatomyositis (DM), in patients suffering from neoplastic disorders represent a medical challenge. The treatment of these conditions has taken on new urgency due to the successful and broad development of cancer-directed immunological-based therapeutic strategies. While primary and secondary PM/DM phenotypes have been pathophysiologically characterized, a rational, stepwise approach to the treatment of patients with ICI-related disease is lacking. In the absence of high-quality evidence to guide clinical judgment, the available data must be critically assessed. In this literature review, we examine partially neglected immunological and clinical findings to obtain insights into the biological profiles of ICI-related PM/DM and potential treatment options. We show that differential diagnosis is essential to stratifying patients according to prognosis and therapeutic impact. Finally, we provide a comprehensive assessment of druggable targets and suggest a stepwise patient-oriented approach for the treatment of ICI-related PM/DM.

Immune checkpoint inhibitors-induced neuromuscular toxicity: From pathogenesis to treatment

Immune checkpoint inhibitors (ICIs) are increasingly used and are becoming the standard of care in the treatment of various tumor types. Despite the favorable results in terms of oncological outcomes, these treatments have been associated with a variety of immune-related adverse events (irAEs). Neurological irAEs are rare but potentially severe. Neuromuscular disorders represent the most common neurological irAEs following anti-PD-1, anti-PD-L1, and anti-CTLA-4 treatment, and include myositis, myasthenia gravis, and demyelinating polyradiculoneuropathy. Instrumental findings may differ from typical neuromuscular disorders occurring outside ICIs treatment. Despite initial severity, neurological irAEs often respond to immune-modulating therapies. Prompt irAEs diagnosis, ICIs discontinuation, and early treatment with corticosteroids, together with patient education and a multi-disciplinary approach, are important for optimizing clinical outcomes. Intravenous immunoglobulin, plasma exchange, and other immune-modulating treatments should be considered in more severe cases. Consideration of re-challenging with the same immunotherapy drug may be given in some cases, based on clinical picture and initial severity of irAEs.

New therapeutic perspectives to manage refractory immune checkpoint-related toxicities

Immune checkpoint inhibitors are reshaping the prognosis of many cancer and are progressively becoming the standard of care in the treatment of many tumour types. Immunotherapy is bringing new hope to patients, but also a whole new spectrum of toxicities for healthcare practitioners to manage. Oncologists and specialists involved in the pluridisciplinary management of patients with cancer are increasingly confronted with the therapeutic challenge of treating patients with severe and refractory immune-related adverse events. In this Personal View, we summarise the therapeutic strategies that have been used to manage such toxicities resulting from immune checkpoint inhibitor treatment. On the basis of current knowledge about their pathogenesis, we discuss the use of new biological and non-biological immunosuppressive drugs to treat severe and steroid refractory immune-related adverse events. Depending on the immune infiltrate type that is predominant, we propose a treatment algorithm for personalised management that goes beyond typical corticosteroid use. We propose a so-called shut-off strategy that aims at inhibiting key inflammatory components involved in the pathophysiological processes of immune-related adverse events, and limits potential adverse effects of drug immunosuppression on tumour response. This approach develops on current guidelines and challenges the step-by-step increase approach to drug immunosuppression.

Immune Response Checkpoint Inhibitors: New Risks of a New Class of Antitumor Agents

The introduction into clinical practice of immune checkpoint inhibitors that block cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein-1 (PD-1), and programmed cell death ligand-1 (PD-L1), has improved the prognosis of patients with malignant neoplasms of diff erent localisation. The antitumour eff ect of immune checkpoint inhibitors is based on blocking CTLA-4 and PD-1/PD-L1 signaling pathways and enhancing lymphocyte antitumour activity. However, inhibition of immune checkpoints may lead to dysregulation of immune responses and appearance of a new type of adverse reactions resulting from changes in the activity of immunocompetent cells. The aim of the study was to analyse adverse reactions associated with the use of immune checkpoint inhibitors. It was demonstrated that the structure of immune-mediated adverse reactions varied depending on the class of immune checkpoint inhibitors. The incidence of immune-mediated adverse reactions was higher with CTLA-4 inhibitors as compared with PD-1/PD-L1 inhibitors, and increased signifi cantly in the case of combination therapy. The treatment with CTLA-4 inhibitors most often resulted in skin reactions (rash, itching), gastrointestinal tract reactions (diarrhea, colitis), and endocrine gland problems (hypophysitis). The treatment with PD-1 inhibitors most often led to respiratory disorders (pneumonitis), and in some cases to gastrointestinal disorders (diarrhea, colitis), skin reactions (rash, itching), and endocrine gland problems (hypothyroidism), but they were less common. The treatment with PD-L1 inhibitors was associated with the development of pneumonitis. The development of immune-mediated adverse reactions may require discontinuation of treatment and administration of immunosuppressants, therefore early diagnosis and timely treatment of complications are important prerequisites for successful antitumour therapy. Further study of the mechanisms of immune-mediated adverse reaction development will optimise antitumour therapy with immune checkpoint inhibitors. 

Severe Neurological Toxicity of Immune Checkpoint Inhibitors: Growing Spectrum

Expanding use of immune-checkpoint inhibitors (ICIs) underscores the importance of accurate diagnosis and timely management of neurological immune-related adverse events (irAE-N). We evaluate the real-world frequency, phenotypes, co-occurring immune-related adverse events (irAEs), and long-term outcomes of severe, grade III to V irAE-N at a tertiary care center over 6 years. We analyze how our experience supports published literature and professional society guidelines. We also discuss these data with regard to common clinical scenarios, such as combination therapy, ICI rechallenge and risk of relapse of irAE-N, and corticosteroid taper, which are not specifically addressed by current guidelines and/or have limited data. Recommendations for management and future irAE-N reporting are outlined. ANN NEUROL 2020;87:659-669.

A review of cancer immunotherapy toxicity

Cancer immunotherapies, including checkpoint inhibitors and adoptive cell therapy, manipulate the immune system to recognize and attack cancer cells. These therapies have the potential to induce durable responses in multiple solid and hematologic malignancies and thus have transformed treatment algorithms for numerous tumor types. Cancer immunotherapies lead to unique toxicity profiles distinct from the toxicities of other cancer therapies, depending on their mechanism of action. These toxicities often require specific management, which can include steroids and immune-modulating therapy and for which consensus guidelines have been published. This review will focus on the toxicities of checkpoint inhibitors and chimeric antigen receptor T cells, including pathophysiology, diagnosis, and management.

Neurotoxicity associated with cancer immunotherapy: immune checkpoint inhibitors and chimeric antigen receptor T-cell therapy

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICPI) and chimeric antigen receptor T cells (CAR-T) represent novel therapies recently approved to treat a number of human cancers. As both approaches modulate the immune system, they can generate a number of immune-related adverse events (irAEs), including a large spectrum of novel neurological toxicities. These are of special interest given their potential severity and risk of compromising further oncologic treatment. We aim to provide a comprehensive review of the literature and discuss their optimal management.

RECENT FINDINGS

In contrast to irAEs involving other organs, neurological complications of ICPI are uncommon, may present throughout the course of treatment and involve the peripheral and central nervous system, including polyneuropathy, myositis, myasthenia gravis, demyelinating polyradiculopathy, myelitis, encephalitis and others. If started early, ICPI-related neurologic irAEs are usually responsive to steroids. In contrast, as many as 40% of patients undergoing CAR-T therapy will develop neurologic complications in the form of a cytokine-release-associated encephalopathy. It includes delirium, aphasia, tremor/myoclonus, seizure and seizure-like activity.

SUMMARY

irAEs associated with CAR-T and ICPI therapy constitute new entities. Early identification and treatment are essential to optimize the functional outcome and further oncologic management of the patient.

Clinical Characteristics and Treatment of Immune-Related Adverse Events of Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) have been changing the paradigm of cancer treatment. However, immune-related adverse effects (irAEs) have also increased with the exponential increase in the use of ICIs. ICIs can break up the immunologic homeostasis and reduce T-cell tolerance. Therefore, inhibition of immune checkpoint can lead to the activation of autoreactive T-cells, resulting in various irAEs similar to autoimmune diseases. Gastrointestinal toxicity, endocrine toxicity, and dermatologic toxicity are common side effects. Neurotoxicity, cardiotoxicity, and pulmonary toxicity are relatively rare but can be fatal. ICI-related gastrointestinal toxicity, dermatologic toxicity, and hypophysitis are more common with anti- CTLA-4 agents. ICI-related pulmonary toxicity, thyroid dysfunction, and myasthenia gravis are more common with PD-1/PD-L1 inhibitors. Treatment with systemic steroids is the principal strategy against irAEs. The use of immune-modulatory agents should be considered in case of no response to the steroid therapy. Treatment under the supervision of multidisciplinary specialists is also essential, because the symptoms and treatments of irAEs could involve many organs. Thus, this review focuses on the mechanism, clinical presentation, incidence, and treatment of various irAEs.

Cancer and older adult patient care

Cancer occurs most frequently in patients aged 65 and older. With the increasing age of the world's population, there will be a significant increase in cancer diagnoses in older adults. Aging imposes a wide variety of physiological responses, comorbidities, and ailments, but older patients are less represented in clinical studies. Specific needs of older patients with cancer often go under-recognized and consequently unmet. In this review, common diagnoses that can affect the outcomes of this population, including frailty, malnutrition, and delirium, are discussed. Areas that need further research to improve the care of geriatric cancer patients, particularly in the hospital settings, are also identified.

An autoimmune-based, paraneoplastic neurologic syndrome following checkpoint inhibition and concurrent radiotherapy for merkel cell carcinoma: case report

PURPOSE

Merkel cell carcinoma is highly sensitive to both radiation and immunotherapy. Moreover, concurrent radioimmunotherapy may capitalize on anti-tumor immune activity and improve Merkel cell treatment response, although an enhanced immune system may cross-react with native tissues and lead to significant sequelae.

METHODS

Here we present a case study of a patient with metastatic Merkel cell carcinoma treated with radiotherapy concurrent with pembrolizumab.

RESULTS

After radioimmunotherapy, the patient developed sensory neuropathy, visual hallucinations, and mixed motor neuron findings. Neurologic dysfunction progressed to profound gastrointestinal dysmotility necessitating parenteral nutrition and intubation with eventual expiration.

CONCLUSION

This case represents a unique autoimmune paraneoplastic neurologic syndrome, likely specific to neuroendocrine tumors and motivated by concurrent radioimmunotherapy. Recognition of the potential role of radioimmunotherapy may provide an advantage in anticipating these severe sequelae.