Rituximab for Immune Checkpoint Inhibitor Myasthenia Gravis

Into the storm: the imbalance in the yin-yang immune response as the commonality of cytokine storm syndromes

There is a continuous cycle of activation and contraction in the immune response against pathogens and other threats to human health in life. This intrinsic yin-yang of the immune response ensures that inflammatory processes can be appropriately controlled once that threat has been resolved, preventing unnecessary tissue and organ damage. Various factors may contribute to a state of perpetual immune activation, leading to a failure to undergo immune contraction and development of cytokine storm syndromes. A literature review was performed to consider how the trajectory of the immune response in certain individuals leads to cytokine storm, hyperinflammation, and multiorgan damage seen in cytokine storm syndromes. The goal of this review is to evaluate how underlying factors contribute to cytokine storm syndromes, as well as the symptomatology, pathology, and long-term implications of these conditions. Although the recognition of cytokine storm syndromes allows for universal treatment with steroids, this therapy shows limitations for symptom resolution and survival. By identifying cytokine storm syndromes as a continuum of disease, this will allow for a thorough evaluation of disease pathogenesis, consideration of targeted therapies, and eventual restoration of the balance in the yin-yang immune response.

Pembrolizumab-induced Myasthenia Gravis and Myocarditis

As the use of immune checkpoint inhibitors (ICPi) such as pembrolizumab is rapidly expanding in the field of immuno-oncology, it is crucial for healthcare providers to be aware of their immune-related adverse events (irAE) which are thought to be driven by augmented immune response of T-cells. While neurologic irAE are underrepresented in literature, their consequences could lead to fatal outcomes. In this report, we describe the case of a patient with excellent performance status prior to pembrolizumab therapy who subsequently suffered myasthenic crisis eventually requiring tracheostomy and long-term mechanical ventilation.

Immune-related adverse events of immune checkpoint inhibitors: a review

Since the first Immune Checkpoint Inhibitor was developed, tumor immunotherapy has entered a new era, and the response rate and survival rate of many cancers have also been improved. Despite the success of immune checkpoint inhibitors, resistance limits the number of patients who can achieve a lasting response, and immune-related adverse events complicate treatment. The mechanism of immune-related adverse events (irAEs) is unclear. We summarize and discuss the mechanisms of action of immune checkpoint inhibitors, the different types of immune-related adverse events and their possible mechanisms, and describe possible strategies and targets for prevention and therapeutic interventions to mitigate them.

Exploring the role of immune checkpoint inhibitors in the etiology of myasthenia gravis and Lambert-Eaton myasthenic syndrome: A systematic review

Background

While immune checkpoint inhibitors (ICIs) have been revolutionary in the treatment of cancer, their administration has been associated with a variety of immune-related adverse events (irAEs), including myasthenia gravis (MG), and Lambert-Eaton myasthenic syndrome (LEMS).

Objective

To provide a comprehensive synthesis of the evidence supporting an etiological role for ICIs in MG and LEMS in patients with no prior history of autoimmune disease.

Hypothesis

ICIs may trigger MG and LEMS in patients with no prior susceptibility to autoimmune disease.

Methods

Relevant primary research on Medline was interrogated using a series of search algorithms. Search terms were constructed based on the PICOS tool endorsed by the Cochrane Collaboration, which describes population, intervention, comparison, outcomes, and study design. Papers were screened according to inclusion and exclusion criteria. Additional papers were retrieved from the reference lists of screened papers. Each paper included in the qualitative synthesis was assigned an integrated metric of evidence (IME) value, ranging from 0 to 7, based on study design, quality of data, likelihood of a causal link between the immune checkpoint inhibitor(s) and MG/LEMS, confidence of MG/LEMS diagnosis, and the number of patients treated with an ICI prior to MG/LEMS diagnosis.

Results

Ninety-four papers describing at least one patient treated with ICI(s) prior to the onset of MG and/or LEMS were documented. Overall evidence for a causal link between ICI administration and MG/LEMS was low, with a median IME value of 2.88 (range 2.05-6.61).

Conclusions

There is a paucity of evidence in support of an etiological relationship between ICIs and MG/LEMS, due largely to the lack of mechanistic studies and/or prospective clinical trials with relevant study endpoints. The current literature is dominated by case reports and retrospective cohort studies, which inherently yield only low-level evidence, supporting the need for further work in this area. A role of ICIs in the etiology of MG/LEMS remains plausible, arguing for continued vigilance for irAEs in patients treated with these drugs. We argue that there is a need for future mechanistic, high quality, large-scale studies specifically investigating the possible etiological role of ICIs in MG/LEMS.

Current landscape and tailored management of immune-related adverse events

Unprecedented advances have been made in immune checkpoint inhibitors (ICIs) in the treatment of cancer. However, the overall benefits from ICIs are impaired by the increasing incidence of immune-related adverse events (irAEs). Although several factors and mechanisms have been proposed in the development of irAEs, there is still incomprehensive understanding of irAEs. Therefore, it is urgent to identify certain risk factors and biomarkers that predict the development of irAEs, as well as to understand the underlying mechanisms of these adverse events. Herein, we comprehensively summarize the state-of-the-art knowledge about clinical features and the related risk factors of irAEs. Particularly, we also discuss relevant mechanisms of irAEs and address the mechanism-based strategies, aiming to develop a tailored management approach for irAEs.

Neuro-ophthalmic complications of immune checkpoint inhibitor therapy: Current status and future directions

Since 2011, use of immune checkpoint inhibitors (ICI) in cancer immunotherapy dramatically expanded, both alone and in combination with either a different cancer treatment or with two different ICIs. With this increase in use have come a myriad of adverse effects from enhanced immune activation, including ophthalmic and neurologic immune related adverse events (irAE). Neuro-ophthalmic immune related adverse events (NOirAE) associated with use of ICIs are increasingly recognized and their severity may actually limit use of potentially life-saving immunotherapy. NOirAEs comprise a wide variety of presentations involving both the central and peripheral nervous system. They cause afferent or efferent visual dysfunction, including among them optic neuropathy and edema, orbital inflammatory disease, and ocular myasthenia. While treatment for irAEs typically involves immunosuppression with corticosteroids, there is no expert consensus regarding best practices for treatment of NOirAEs and whether to stop ICI immunotherapy for the cancer or not. This state-of-the-art review explores the pathophysiologic basis for NOirAEs, provides a framework for categorizing them within neuro-ophthalmology, and discusses what is needed to close the current knowledge gaps in diagnosis and management of an increasing population of cancer patients requiring neuro-ophthalmic care.

Pembrolizumab-induced Myasthenia Gravis Relapse after Immunosuppressive Therapy

Myasthenia gravis (MG) is an immune-related adverse event (irAE), and as an irAE, MG (irAE-MG) generally has a monophasic course, with only a few case reports of irAE-MG flare-ups during the course of the disease. We herein report a case of pembrolizumab-induced MG with relapsing symptoms. irAE-MG is a rare disease that has not yet been fully characterized, and our case shows that MG symptoms may relapse. Therefore, regular follow-up is necessary, even after the symptoms improve with immunosuppressive therapy.

TNF-α Inhibitors and Other Biologic Agents for the Treatment of Immune Checkpoint Inhibitor-Induced Myocarditis

With anti-PD-1 antibodies serving as a representative drug, immune checkpoint inhibitors (ICIs) have become the main drugs used to treat many advanced malignant tumors. However, immune-related adverse events (irAEs), which might involve multiple organ disorders, should not be ignored. ICI-induced myocarditis is an uncommon but life-threatening irAE. Glucocorticoids are the first choice of treatment for patients with ICI-induced myocarditis, but high proportions of steroid-refractory and steroid-resistant cases persist. According to present guidelines, tumor necrosis factor alpha (TNF-α) inhibitors are recommended for patients who fail to respond to steroid therapy and suffer from severe cardiac toxicity, although evidence-based studies are lacking. On the other hand, TNF-α inhibitors are contraindicated in patients with moderate-to-severe heart failure. This review summarizes real-world data from TNF-α inhibitors and other biologic agents for ICI-induced myocarditis to provide more evidence of the efficacy and safety of TNF-α inhibitors and other biologic agents.

Rituximab in Refractory Myositis and Acute Neuropathy Secondary to Checkpoint Inhibitor Therapy

Checkpoint inhibitor immunotherapies have been one of the latest advances through the last decade in the treatment of various cancers. As their use is increasing so is the knowledge of their complications which can affect various organ systems including the central and peripheral nervous systems. Management of these complications requires stopping the offending agent and in some cases treating with immunosuppressive agents like intravenous steroids. Physicians can face challenging situations if patients are unresponsive to steroids, intravenous immunoglobulins (IVIG), and plasmapheresis (PLEX). There are no formal guidelines to help in the management of such patients. 

We present an 85-year-old male with a past medical history of renal cell carcinoma status post nephrectomy who was admitted with diplopia, eyelid ptosis, dysphagia, dysphonia, dyspnea, and generalized weakness. He was started on nivolumab and ipilimumab 10 days prior to presentation. Laboratory studies showed an elevated erythrocyte sedimentation rate, C-reactive protein, and creatine phosphokinase, and an unrevealing lumbar puncture. Acetylcholine receptor (AChR) and muscle-specific kinase (MuSK) antibodies were negative. Electromyography and nerve conduction studies showed axonal and demyelinating sensorimotor neuropathy with no significant decrement on 3 Hz repetitive stimulation. Thyroid function tests were concerning for thyroiditis and anti-thyroid peroxidase antibodies were positive. Together, these findings led to the diagnosis of refractory myositis and acute neuropathy along with autoimmune thyroiditis from nivolumab and ipilimumab immunotherapy. His symptoms were unresponsive to a 5-day course of steroids, intravenous immunoglobulins, and plasmapheresis. He was then started on rituximab with significant improvement in ptosis, dysphagia, dysphonia, and proximal weakness. Immune checkpoint inhibitors (ICI) are associated with an increased risk for the development of various autoimmune conditions. Treatment involves discontinuation of the offending drug and initiation of immunosuppressive therapy.

This case is interesting as it demonstrates the importance of the awareness of the neurological complications of the checkpoint inhibitor therapies and the beneficial role of rituximab in patients who are unresponsive to initial immunosuppressive therapies including steroids, IVIG, and PLEX.