LB0002 Safety and Tolerability of Arimoclomol in Patients with Sporadic Inclusion Body Myositis: A Randomised, Double-Blind, Placebo-Controlled, Phase IIa Proof-of-Concept Trial

Novel and potential future therapeutic options in systemic autoimmune diseases

Autoimmune inflammation is caused by the loss of tolerance to specific self-antigens and can result in organ-specific or systemic disorders. Systemic autoimmune diseases affect a significant portion of the population with an increasing rate of incidence, which means that is essential to have effective therapies to control these chronic disorders. Unfortunately, several patients with systemic autoimmune diseases do not respond at all or just partially respond to available conventional synthetic disease-modifying antirheumatic drugs and targeted therapies. However, during the past few years, some new medications have been approved and can be used in real-life clinical settings. Meanwhile, several new candidates appeared and can offer promising novel treatment options in the future. Here, we summarize the newly available medications and the most encouraging drug candidates in the treatment of systemic lupus erythematosus, rheumatoid arthritis, Sjögren's disease, systemic sclerosis, systemic vasculitis, and autoimmune myositis.

Autoimmune inflammatory myopathies

The autoimmune inflammatory myopathies constitute a heterogeneous group of acquired myopathies that have in common the presence of endomysial inflammation and moderate to severe muscle weakness. Based on currently evolved distinct clinical, histologic, immunopathologic, and autoantibody features, these disorders can be best classified as dermatomyositis, necrotizing autoimmune myositis, antisynthetase syndrome-overlap myositis, and inclusion body myositis. Although polymyositis is no longer considered a distinct subset but rather an extinct entity, it is herein described because its clinicopathologic information has provided over many years fundamental information on T-cell-mediated myocytotoxicity, especially in reference to inclusion body myositis. Each inflammatory myopathy subset has distinct immunopathogenesis, prognosis, and response to immunotherapies, necessitating the need to correctly diagnose each subtype from the outset and avoid disease mimics. The paper describes the main clinical characteristics that aid in the diagnosis of each myositis subtype, highlights the distinct features on muscle morphology and immunopathology, elaborates on the potential role of autoantibodies in pathogenesis or diagnosis , and clarifies common uncertainties in reference to putative triggering factors such as statins and viruses including the 2019-coronavirus-2 pandemic. It extensively describes the main autoimmune markers related to autoinvasive myocytotoxic T-cells, activated B-cells, complement, cytokines, and the possible role of innate immunity. The concomitant myodegenerative features seen in inclusion body myositis along with their interrelationship between inflammation and degeneration are specifically emphasized. Finally, practical guidelines on the best therapeutic approaches are summarized based on up-to-date knowledge and controlled studies, highlighting the prospects of future immunotherapies and ongoing controversies.

Therapieoptionen und outcome bei idiopathischen entzündlichen Muskelerkrankungen

Die idiopathischen entzündlichen Muskelerkrankungen (IIM) sind eine sehr heterogene Gruppe, die sich immer besser differenzieren lässt. Damit eröffnen sich mehr Möglichkeiten für gezieltere Therapien, die zum einen auf die Veränderung pathogenetischer Faktoren gerichtet sind. Zum anderen sollen sie Krankheitsaktivität vermindern, Muskelaufbau fördern, Organschäden verhindern und Lebensqualität verbessern.

Die folgende Übersichtsarbeit fasst die vorhandenen Daten zu bereits angewandten Behandlungen in der Praxis zusammen und gibt einen Ausblick auf zukünftige Alternativen.

Für die Polymyositis (PM) und Dermatomyositis (DM) sind Glukokortikoide weiter unverzichtbarer Therapiebestandteil. Eine frühe Kombination mit konventionellen DMARDs hat sich durchgesetzt. Die ProDerm- Studie stellt für die Immunglobulintherapie in der Praxis eine gute Basis dar. Rituximab (RTX) löst Cyclophosphamid (CYC) bei schweren Verlaufsformen immer mehr ab.

Für Abatacept, Jak-Kinase-Hemmer, Apremilast, Sifalimumab und Lenabasum müssen vielversprechende erste Ergebnisse durch weiter Studien untermauert werden. Anspruchsvoll ist die Behandlung bei extramuskulärer Beteiligung. Von großem Interesse ist der zukünftige Stellenwert von Nintedanib bei der interstitiellen Lungenerkrankung im Rahmen einer Myositis (IIM-ILD).

Die Therapie der Einschlusskörperchen- Myositis (IBM) ist immer noch eine große Herausforderung. Zahlreiche Studien haben bisher nicht überzeugend zu einer Besserung der Prognose führen können. Spätestens bei therapierefraktärem Verlauf sollte an eine Malignom- assoziierte Myositis gedacht werden. Gelegentlich verbirgt sich auch eine hereditäre Myopathie hinter einer, zum Beispiel durch einen Infekt oder Überlastung getriggerten, Myositis.

Komplikationen im Verlauf, wie Dysphagie, Infektionen, Myokardbeteiligung stellen keine Seltenheit dar. Häufig besteht Multimorbidität. Eine interdisziplinäre Zusammenarbeit in einem kompetenten Team, in dem erfahrene Physio-, Ergo- und Psychotherapeuten fester Bestandteil sind, ist unabdingbar für eine erfolgreiche Begleitung dieser Patienten.

Idiopathic Inflammatory Myopathies: Clinical Approach and Management

Idiopathic inflammatory myopathies (IIM) are a group of chronic, autoimmune conditions affecting primarily the proximal muscles. The most common types are dermatomyositis (DM), polymyositis (PM), necrotizing autoimmune myopathy (NAM), and sporadic inclusion body myositis (sIBM). Patients typically present with sub-acute to chronic onset of proximal weakness manifested by difficulty with rising from a chair, climbing stairs, lifting objects, and combing hair. They are uniquely identified by their clinical presentation consisting of muscular and extramuscular manifestations. Laboratory investigations, including increased serum creatine kinase (CK) and myositis specific antibodies (MSA) may help in differentiating clinical phenotype and to confirm the diagnosis. However, muscle biopsy remains the gold standard for diagnosis. These disorders are potentially treatable with proper diagnosis and initiation of therapy. Goals of treatment are to eliminate inflammation, restore muscle performance, reduce morbidity, and improve quality of life. This review aims to provide a basic diagnostic approach to patients with suspected IIM, summarize current therapeutic strategies, and provide an insight into future prospective therapies.

Sporadic Inclusion Body Myositis Manifesting as Isolated Muscle Weakness of the Finger Flexors Three Years after Disease Onset

Sporadic inclusion body myositis (sIBM) is a chronic progressive myopathy characterized by muscle weakness of both the quadriceps femoris and finger flexors. We herein present the case of a typical male patient with sIBM, which manifested as the isolated weakness of the finger flexors three years after the disease onset. We have identified several patients with sIBM in our cohort with muscle weakness of the flexors but not the quadriceps femoris. Examination of the flexor digitorum profundus muscle is important for the early and proper diagnosis of sIBM, even if a patient only presents with isolated finger flexor muscle weakness.

Treatment for inclusion body myositis

BACKGROUND

Inclusion body myositis (IBM) is a late-onset inflammatory muscle disease (myopathy) associated with progressive proximal and distal limb muscle atrophy and weakness. Treatment options have attempted to target inflammatory and atrophic features of this condition (for example with immunosuppressive and immunomodulating drugs, anabolic steroids, and antioxidant treatments), although as yet there is no known effective treatment for reversing or minimising the progression of inclusion body myositis. In this review we have considered the benefits, adverse effects, and costs of treatment in targeting cardinal effects of the condition, namely muscle atrophy, weakness, and functional impairment.

OBJECTIVES

To assess the effects of treatment for IBM.

SEARCH METHODS

On 7 October 2014 we searched the Cochrane Neuromuscular Disease Group Specialized Register, the Cochrane Central Register for Controlled Trials (CENTRAL), MEDLINE, and EMBASE. Additionally in November 2014 we searched clinical trials registries for ongoing or completed but unpublished trials.

SELECTION CRITERIA

We considered randomised or quasi-randomised trials, including cross-over trials, of treatment for IBM in adults compared to placebo or any other treatment for inclusion in the review. We specifically excluded people with familial IBM and hereditary inclusion body myopathy, but we included people who had connective tissue and autoimmune diseases associated with IBM, which may or may not be identified in trials. We did not include studies of exercise therapy or dysphagia management, which are topics of other Cochrane systematic reviews.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures.

MAIN RESULTS

The review included 10 trials (249 participants) using different treatment regimens. Seven of the 10 trials assessed single agents, and 3 assessed combined agents. Many of the studies did not present adequate data for the reporting of the primary outcome of the review, which was the percentage change in muscle strength score at six months. Pooled data from two trials of interferon beta-1a (n = 58) identified no important difference in normalised manual muscle strength sum scores from baseline to six months (mean difference (MD) -0.06, 95% CI -0.15 to 0.03) between IFN beta-1a and placebo (moderate-quality evidence). A single trial of methotrexate (MTX) (n = 44) provided moderate-quality evidence that MTX did not arrest or slow disease progression, based on reported percentage change in manual muscle strength sum scores at 12 months. None of the fully published trials were adequately powered to detect a treatment effect. We assessed six of the nine fully published trials as providing very low-quality evidence in relation to the primary outcome measure. Three trials (n = 78) compared intravenous immunoglobulin (combined in one trial with prednisone) to a placebo, but we were unable to perform meta-analysis because of variations in study analysis and presentation of trial data, with no access to the primary data for re-analysis. Other comparisons were also reported in single trials. An open trial of anti-T lymphocyte immunoglobulin (ATG) combined with MTX versus MTX provided very low-quality evidence in favour of the combined therapy, based on percentage change in quantitative muscle strength sum scores at 12 months (MD 12.50%, 95% CI 2.43 to 22.57). Data from trials of oxandrolone versus placebo, azathioprine (AZA) combined with MTX versus MTX, and arimoclomol versus placebo did not allow us to report either normalised or percentage change in muscle strength sum scores. A complete analysis of the effects of arimoclomol is pending data publication. Studies of simvastatin and bimagrumab (BYM338) are ongoing. All analysed trials reported adverse events. Only 1 of the 10 trials interpreted these for statistical significance. None of the trials included prespecified criteria for significant adverse events.

AUTHORS' CONCLUSIONS

Trials of interferon beta-1a and MTX provided moderate-quality evidence of having no effect on the progression of IBM. Overall trial design limitations including risk of bias, low numbers of participants, and short duration make it difficult to say whether or not any of the drug treatments included in this review were effective. An open trial of ATG combined with MTX versus MTX provided very low-quality evidence in favour of the combined therapy based on the percentage change data given. We were unable to draw conclusions from trials of IVIg, oxandrolone, and AZA plus MTX versus MTX. We need more randomised controlled trials that are larger, of longer duration, and that use fully validated, standardised, and responsive outcome measures.

Sporadic inclusion body myositis: new insights and potential therapy

PURPOSE OF THE REVIEW

To describe new insights and developments in the pathogenesis, diagnosis and treatment of sporadic inclusion body myositis (IBM).

RECENT FINDINGS

Various hypothesis about the pathogenesis of IBM continue to be investigated, including autoimmune factors, mitochondrial dysfunction, protein dyshomeostasis, altered nucleic acid metabolism, myonuclear degeneration and the role of the myostatin pathway. Serum autoantibodies against cytosolic 5'-nucleotidase 1A have been identified in IBM showing moderate diagnostic performance. The differential diagnostic value of histopathological features, including different protein aggregates, continues to be evaluated. MRI may also be of monitoring value in IBM. New therapeutic strategies are being tested in IBM patients, namely the upregulation of the heat shock response and the antagonism of myostatin.

SUMMARY

Recent important advances have occurred in IBM. These advances, including recent and ongoing clinical trials, may lead to earlier diagnosis and improved understanding and treatment of the disease. Despite improved knowledge, IBM continues to be a puzzling disease and the pathogenesis remains to be clarified. An interdisciplinary, bench to bedside translational research approach is crucial for the successful identification of novel treatments for this debilitating, currently untreatable disorder.

Ongoing developments in sporadic inclusion body myositis

Sporadic inclusion body myositis (IBM) is an acquired muscle disorder associated with ageing, for which there is no effective treatment. Ongoing developments include: genetic studies that may provide insights regarding the pathogenesis of IBM, improved histopathological markers, the description of a new IBM autoantibody, scrutiny of the diagnostic utility of clinical features and biomarkers, the refinement of diagnostic criteria, the emerging use of MRI as a diagnostic and monitoring tool, and new pathogenic insights that have led to novel therapeutic approaches being trialled for IBM, including treatments with the objective of restoring protein homeostasis and myostatin blockers. The effect of exercise in IBM continues to be investigated. However, despite these ongoing developments, the aetiopathogenesis of IBM remains uncertain. A translational and multidisciplinary collaborative approach is critical to improve the diagnosis, treatment, and care of patients with IBM.

Update in inclusion body myositis

PURPOSE OF REVIEW

The purpose of this study is to review recent scientific advances relating to the natural history, cause, treatment and serum and imaging biomarkers of inclusion body myositis (IBM).

RECENT FINDINGS

Several theories regarding the aetiopathogenesis of IBM are being explored and new therapeutic approaches are being investigated. New diagnostic criteria have been proposed, reflecting the knowledge that the diagnostic pathological findings may be absent in patients with clinically typical IBM. The role of MRI in IBM is expanding and knowledge about pathological biomarkers is increasing. The recent description of autoantibodies to cytosolic 5' nucleotidase 1A in patients with IBM is a potentially important advance that may aid early diagnosis and provides new evidence regarding the role of autoimmunity in IBM.

SUMMARY

IBM remains an enigmatic and often misdiagnosed disease. The pathogenesis of the disease is still not fully understood. To date, pharmacological treatment trials have failed to show clear efficacy. Future research should continue to focus on improving understanding of the pathophysiological mechanisms of the disease and on the identification of reliable and sensitive outcome measures for clinical trials. IBM is a rare disease and international multicentre collaboration for trials is important to translate research advances into improved patient outcomes.