Immune-mediated myopathy related to anti 3-hydroxy-3-methylglutaryl-coenzyme A reductase antibodies as an emerging cause of necrotizing myopathy induced by statins

Immune-mediated necrotizing myopathy with pembrolizumab: a specific neuromuscular entity

PURPOSE

Pembrolizumab is a humanized monoclonal antibody that binds to the programmed cell-death protein-1 (PD-1) on immune T-cells, thus blocking PD-1 activity. Pembrolizumab is indicated for the treatment of advanced melanoma, metastatic non-small-cell lung cancer, and head and neck squamous cell carcinoma. However, it is associated with immune-related adverse events.

METHODS

We investigated the association between pembrolizumab and immune-mediated necrotizing myopathy (IMNM). We analyzed reports in the World Health Organization's global individual case safety report database, Vigibase, up to January 2020 with the MedDRA lower level term "IMNM." The association between exposure to pembrolizumab and occurrence of the adverse event was estimated by disproportionality analysis. The reporting odds ratio (ROR) was calculated with 95% confidence intervals (CIs). We analyzed the criteria of diagnosis of the adverse reaction.

RESULTS

Five-hundred sixty-seven notifications were identified as IMNM of which 14 with pembrolizumab. The ROR was 17.59 (95% CI: 9.4-32.9).

CONCLUSION

The diagnosis of IMNM does not always take into account recent criteria for the diagnosis of this pathology. This study highlights the existence of a signal, as well as the need for collaboration between oncologists and neurologists for these neurological pathologies.

Atorvastatin-Induced Necrotizing Myopathy and its Response to Combination Therapy

Atorvastatin is the most commonly used statin medication to decrease cholesterol levels and prevent atherosclerosis. Myopathy is a reported side effect of atorvastatin which can happen even after more than six months after starting the medication. The side effect on the muscle tissue can range from simple reversible myalgia to respiratory muscle compromise. Here we present a 46-year-old male who presented with myopathy after taking atorvastatin for two years. Biopsy proved immune-mediated necrotizing myopathy which responded to a combination of Rituximab and intravenous immunoglobulin therapy.

Initial seronegative immune-mediated necrotising myopathy with subsequent anti-HMGCR antibody development and response to rituximab: case report

Background

Immune-mediated necrotising myopathy (IMNM) is characterised by severe muscle weakness and necrosis with a paucity of inflammation on muscle biopsy. Around 60% of cases are associated with antibodies to the signal recognition particle (SRP) or 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR); the remainder are seronegative. IMNM is more treatment resistant than inflammatory myopathies.

Case presentation

A 69-year-old woman with previous statin exposure presented aged 63 with muscle weakness and raised creatinine kinase (CK). Anti-SRP and anti-HMGCR antibodies were not detected, but muscle biopsy revealed changes consistent with necrotising myopathy. Statins were discontinued, and she was treated with prednisolone and methotrexate achieving disease remission. Clinical and biochemical parameters were largely stable until 6 years after diagnosis she experienced a rapid deterioration. This was found to be associated with new development of anti-HMGCR antibody. Rituximab was commenced, resulting rapidly in remission. She has remained in remission since, following 2 cycles of rituximab.

Conclusions

To our knowledge, this is the first reported case of serologically negative IMNM whose subsequent rapid deterioration was associated with development of anti-HMGCR antibody. The response to rituximab and subsequent sustained remission suggests a role for early use of rituximab in aggressive cases of anti-HMGCR myopathy.

Statin-Associated Autoimmune Myopathy: A Systematic Review of 100 Cases

BACKGROUND

Statins are a group of drugs that reduce the levels of triglycerides and cholesterol in blood by inhibiting HMG-CoA reductase, an enzyme involved in rate limiting step in cholesterol synthesis. About 2-20% patients on statins develop toxic myopathies, which usually resolve on discontinuation of statin. More recently, an immune-mediated necrotizing myopathy has been found to be associated with statin use which in most cases requires treatment with immunosuppressants.

OBJECTIVE

To perform a systematic review on published case reports and case series of statin-associated autoimmune myopathy.

METHODS

A comprehensive search of PUBMED, EMBASE, Cochrane library and ClinicalTrials.gov databases was performed for relevant articles from inception until March 19, 2016 to identify cases of statin-associated necrotizing myopathy and characterize their symptoms, evaluation and response to treatment.

RESULTS

A total of 16 articles describing 100 patients with statin-associated autoimmune myopathy were identified. The mean age of presentation was 64.72 years, and 54.44% were males. The main presenting clinical feature was proximal muscle weakness, which was symmetric in 83.33% of patients. The mean creatine kinase (CK) was 6853 IU/l. Anti-HMG-CoA reductase antibody was positive in all cases tested (n = 57/57, 100%). In patients with no anti-HMG-CoA antibody results, diagnosis was established by findings of necrotizing myopathy on biopsy. Among the 83 cases where muscle biopsy information was available, 81.48% had necrosis, while 18.51% had combination of necrosis and inflammation. Most (83.82%) patients received two or more immunosuppressants to induce remission. Ninety-one percent had resolution of symptoms after treatment.

CONCLUSION

Statin-associated necrotizing myopathy is a symmetric proximal muscle weakness associated with extreme elevations of CK. It is common in males and can occur after months of statin use. It is associated with necrosis on muscle biopsy and the presence of anti-HMG-CoA reductase antibodies. It usually requires discontinuation and immune suppression for resolution. Rechallenge with statin is unsuccessful in most cases.

Current and future therapies for addressing the effects of inflammation on HDL cholesterol metabolism

Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Inflammatory processes arising from metabolic abnormalities are known to precipitate the development of CVD. Several metabolic and inflammatory markers have been proposed for predicting the progression of CVD, including high density lipoprotein cholesterol (HDL-C). For ~50 years, HDL-C has been considered as the atheroprotective 'good' cholesterol because of its strong inverse association with the progression of CVD. Thus, interventions to increase the concentration of HDL-C have been successfully tested in animals; however, clinical trials were unable to confirm the cardiovascular benefits of pharmaceutical interventions aimed at increasing HDL-C levels. Based on these data, the significance of HDL-C in the prevention of CVD has been called into question. Fundamental in vitro and animal studies suggest that HDL-C functionality, rather than HDL-C concentration, is important for the CVD-preventive qualities of HDL-C. Our current review of the literature positively demonstrates the negative impact of systemic and tissue (i.e. adipose tissue) inflammation in the healthy metabolism and function of HDL-C. Our survey indicates that HDL-C may be a good marker of adipose tissue health, independently of its atheroprotective associations. We summarize the current findings on the use of anti-inflammatory drugs to either prevent HDL-C clearance or improve the function and production of HDL-C particles. It is evident that the therapeutic agents currently available may not provide the optimal strategy for altering HDL-C metabolism and function, and thus, further research is required to supplement this mechanistic approach for preventing the progression of CVD.

LINKED ARTICLES

This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

A short-term statin treatment changes the contractile properties of fast-twitch skeletal muscles

Background

Cumulative evidence indicates that statins induce myotoxicity. However, the lack of understanding of how statins affect skeletal muscles at the structural, functional, and physiological levels hampers proper healthcare management. The purpose of the present study was to investigate the early after-effects of lovastatin on the slow-twitch soleus (Sol) and fast-twitch extensor digitorum longus (EDL) muscles.

Methods

Adult C57BL/6 mice were orally administrated with placebo or lovastatin [50 mg/kg/d] for 28 days. At the end of the treatment, the isometric ex vivo contractile properties of the Sol and EDL muscles were measured. Subtetanic and tetanic contractions were assessed and contraction kinetics were recorded. The muscles were then frozen for immunohistochemical analyses. Data were analyzed by two-way ANOVA followed by an a posteriori Tukey’s test.

Results

The short-term lovastatin treatment did not induce muscle mass loss, muscle fiber atrophy, or creatine kinase (CK) release. It had no functional impact on slow-twitch Sol muscles. However, subtetanic stimulations at 10 Hz provoked greater force production in fast-twitch EDL muscles. The treatment also decreased the maximal rate of force development (dP/dT) of twitch contractions and prolonged the half relaxation time (1/2RT) of tetanic contractions of EDL muscles.

Conclusions

An early short-term statin treatment induced subtle but significant changes in some parameters of the contractile profile of EDL muscles, providing new insights into the selective initiation of statin-induced myopathy in fast-twitch muscles.

Treatment of muscle weakness in neuromuscular disorders

INTRODUCTION

Weakness is one of the predominant clinical manifestations of neuromuscular disorders (NMDs), which strongly influences daily life, prognosis, and outcome of affected patients. One of the major therapeutic goals in NMD-patients is to completely resolve muscle weakness. Various treatment options are available and include physical therapy, electrotherapy, diet, drugs, avoidance or withdrawal of muscle-toxic and weakness-inducing agents, detoxification, stem-cell-therapy, plasma-exchange, respiratory therapy, or surgery. Most accessible to treatment is weakness from immune-mediated neuropathies, immune-mediated transmission-disorders, and idiopathic immune myopathies. Areas covered: This manuscript aims to summarize and discuss recent findings and future perspectives concerning the treatment of muscle weakness in NMDs. Data were obtained by a literature search in databases such as PubMed and Current-Contents. Expert commentary: Weakness is most easily treatable in acquired NMDs and in hereditary myopathies and neuropathies beneficial treatment options are also available. Research needs to be encouraged and intensified to further expand the spectrum of treatment options for weakness.

ToxEvaluator: an integrated computational platform to aid the interpretation of toxicology study-related findings

Attempts are frequently made to investigate adverse findings from preclinical toxicology studies in order to better understand underlying toxicity mechanisms. These efforts often begin with limited information, including a description of the adverse finding, knowledge of the structure of the chemical associated with its cause and the intended pharmacological target. ToxEvaluator was developed jointly by Pfizer and the Comparative Toxicogenomics Database (http://ctdbase.org) team at North Carolina State University as an in silico platform to facilitate interpretation of toxicity findings in light of prior knowledge. Through the integration of a diverse set of in silico tools that leverage a number of public and proprietary databases, ToxEvaluator streamlines the process of aggregating and interrogating diverse sources of information. The user enters compound and target identifiers, and selects adverse event descriptors from a safety lexicon and mapped MeSH disease terms. ToxEvaluator provides a summary report with multiple distinct areas organized according to what target or structural aspects have been linked to the adverse finding, including primary pharmacology, structurally similar proprietary compounds, structurally similar public domain compounds, predicted secondary (i.e. off-target) pharmacology and known secondary pharmacology. Similar proprietary compounds and their associated in vivo toxicity findings are reported, along with a link to relevant supporting documents. For similar public domain compounds and interacting targets, ToxEvaluator integrates relationships curated in Comparative Toxicogenomics Database, returning all direct and inferred linkages between them. As an example of its utility, we demonstrate how ToxEvaluator rapidly identified direct (primary pharmacology) and indirect (secondary pharmacology) linkages between cerivastatin and myopathy.

Immune-mediated necrotising myopathy associated with antibodies to the signal recognition particle treated with a combination of rituximab and cyclophosphamide

A 50-year-old man presented with dysphagia and proximal muscle weakness. He was diagnosed with immune-mediated necrotising myopathy associated with antibodies to the signal recognition particle. After an initial response following treatment with high-dose steroids, intravenous immunoglobulin and methotrexate, there was a relapse of the immune condition. The clinical deterioration occurred less than 2 months after disease onset. The refractoriness of this disease was characterised by an increase of the already severe muscle wasting that led to respiratory failure and progressive dysphagia, regardless of the immunosuppressant treatment. At this time the patient was referred to our department. He was restarted on intravenous pulses of methylprednisolone associated with intravenous cyclophosphamide, but with no effect. After 3 weeks, rituximab was started with a dramatic and progressive improvement. There were no complications associated with rituximab/cyclophosphamide treatment and the disease has been kept in remission, for the last 3 years.

Autoantibodies 2015: From diagnostic biomarkers toward prediction, prognosis and prevention

At the 12th International Workshop on Autoantibodies and Autoimmunity (IWAA), organized in August 2014 in Sao Paulo, Brazil, more than 300 autoimmunologists gathered to discuss the status of many novel autoantibodies in clinical practice, and to envisage additional value of autoantibodies in terms of prediction, prognosis and prevention of autoimmune diseases. Two separate workshops were dedicated to standardization and harmonization of autoantibody testing and nomenclature: International Autoantibody Standardization (IAS) and International Consensus on ANA Patterns (ICAP). It was apparent to all in attendance that the discovery and elucidation of novel autoantibodies did not slow down, but that multiple challenges lay ahead of us in order to apply these discoveries to effective and efficient clinical practice. Importantly, this requires optimal bidirectional communication between clinicians and laboratory specialists, as well as close collaboration with the diagnostic industry. This paper is a report on the 12th IWAA in combination with a review of the recent developments in the field of autoantibodies.