213th ENMC International Workshop: Outcome measures and clinical trial readiness in idiopathic inflammatory myopathies, Heemskerk, The Netherlands, 18-20 September 2015

272nd ENMC international workshop: 10 Years of progress - revision of the ENMC 2013 diagnostic criteria for inclusion body myositis and clinical trial readiness. 16-18 June 2023, Hoofddorp, The Netherlands

Since the publication of the 2013 European Neuromuscular Center (ENMC) diagnostic criteria for Inclusion Body Myositis (IBM), several advances have been made regarding IBM epidemiology, pathogenesis, diagnostic tools, and clinical trial readiness. Novel diagnostic tools include muscle imaging techniques such as MRI and ultrasound, and serological testing for cytosolic 5'-nucleotidase-1A antibodies. The 272nd ENMC workshop aimed to develop new diagnostic criteria, discuss clinical outcome measures and clinical trial readiness. The workshop started with patient representatives highlighting several understudied symptoms and the urge for a timely diagnosis. This was followed by presentations from IBM experts highlighting the new developments in the field. This report is composed of two parts, the first part providing new diagnostic criteria on which consensus was achieved. The second part focuses on the use of outcome measures in clinical practice and clinical trials, highlighting current limitations and outlining the goals for future studies.

Increased expression of the p-STAT3/IL-17 signaling pathway in patients with dermatomyositis

OBJECTIVES

The aim is to explore the roles of phosphorylated signal transduction and activator of transcription 3 (p-STAT3) and interleukin (IL)-17 in patients with dermatomyositis (DM).

METHODS

A total of 20 DM patients and 12 healthy controls were enrolled. Flow cytometry combined with counting was used to detect the number of Th17 cells. Western blotting and immunohistochemistry were used to examine the muscle levels of p-STAT3 and IL-17, and serum levels of IL-17 were measured by enzyme-linked immunosorbent assays.

RESULTS

Muscle p-STAT3 and IL-17 levels, the number of Th17 cells, and serum IL-17 levels were markedly increased in DM. p-STAT3 and IL-17 were co-expressed in the muscle of DM patients. The p-STAT3 levels were correlated with the number of Th17 cells as well as muscle and serum IL-17 levels. The correlations of the p-STAT3 level with elevated levels of transaminases, myocardial enzymes, and the health assessment questionnaire score were significantly positive, while the correlation with manual muscle testing-8 was significantly negative. A receiver operating characteristic curve indicated the good predictive value of p-STAT3 for the occurrence of DM.

CONCLUSIONS

The increased p-STAT3/IL-17 signaling pathway activation in DM patients may induce muscle inflammation and necrosis, and it may be a potential target for DM.

Assessment of disability in idiopathic inflammatory myopathy: a call for linearity

Objectives

To evaluate the clinimetric properties of the Academic Medical Centre Disability Score (ALDS) in patients with idiopathic inflammatory myopathy (IIM).

Methods

We used prospectively collected data of IIM patients who completed a phase-2 study with first-line IVIG monotherapy. The ALDS is a patient-reported questionnaire which contains 25 items relevant for disability in myositis. ALDS and all core set measures (CSMs) for myositis [including HAQ-Disability Index (HAQ-DI)] were evaluated at baseline and 9 weeks follow-up. In addition, the 2016 ACR/EULAR myositis response criteria outcome called Total Improvement Score (TIS) was evaluated at 9 weeks. We examined floor/ceiling effects, reliability and construct validity of the ALDS. To examine known-group validity, ALDS change scores over time were compared with TIS and physician impression of clinical response.

Results

Nineteen patients with IIM [median age 59 years, 12 (63%) female] were enrolled. At baseline, ALDS showed a median score of 65.4 (IQR 58.2–73.5), good Cronbach’s alpha (α = 0.84) and a small ceiling effect (11%). Construct validity was confirmed by moderate to strong correlations between ALDS and HAQ-DI [r_s = −0.57 (baseline); −0.86 (follow-up)]. ALDS change score correlated with TIS (r_s = 0.70), discriminated between responders and non-responders (TIS ≥ 40; P = 0.001), between groups based on physician impression of clinical response (P = 0.03), and detected deterioration.

Conclusion

The ALDS showed promising clinimetric properties and detected relevant changes in disability in patients with myositis. These results warrant further investigations.

Myo-Spain: Spanish Registry of patients with idiopathic inflammatory myopathy. Methodology

OBJECTIVES

To describe the methods of the Spanish Registry of patients with idiopathic inflammatory myopathy (IIM) (Myo-Spain), as well as its strengths and limitations. The main objective of the project is to analyse the evolution and clinical management of a cohort of patients with IIM.

METHODS

Observational, longitudinal, ambispective and multicentre study of a cohort of patients with IIM seen in rheumatology units in Spain. All patients with a diagnosis of IMM will be included in the regular follow-up of the participating centres, regardless of age on initiation of the process. Incident cases will be all patients who at the beginning of the study have been diagnosed for less than 12 months and prevalent cases for more than 12 months. The registry will include data from the visit at baseline, one year and two years. Socio-demographic, clinical, analytical variables, complications, comorbidities, association with other rheumatic diseases, hospital admissions, mortality and treatments will be collected. In addition, indices, scales and questionnaires of activity, muscle involvement, damage, disability, and quality of life will be determined. The recruitment period will be 23 months. The purpose is to obtain a cohort of 400 patients with IMM.

CONCLUSIONS

Myo-Spain registry provides the opportunity to develop a cohort of incident and prevalent patients with IMM in Spain. Myo-Spain will be able to assess in detail the clinical characteristics of the disease at different times. The comprehensive information collected during the visits is expected to provide a broad source of data for future analysis.

Myo-Spain: Spanish Registry of Patients with Idiopathic Inflammatory Myopathy. Methodology

OBJECTIVES

To describe the methods of the Spanish Registry of patients with idiopathic inflammatory myopathy (IIM) (Myo-Spain), as well as its strengths and limitations. The main objective of the project is to analyse the evolution and clinical management of a cohort of patients with IIM.

METHODS

Observational, longitudinal, ambispective and multicentre study of a cohort of patients with IIM seen in rheumatology units in Spain. All patients with a diagnosis of IMM will be included in the regular follow-up of the participating centres, regardless of age on initiation of the process. Incident cases will be all patients who at the beginning of the study have been diagnosed for less than 12 months and prevalent cases for more than 12 months. The registry will include data from the visit at baseline, one year and two years. Socio-demographic, clinical, analytical variables, complications, comorbidities, association with other rheumatic diseases, hospital admissions, mortality and treatments will be collected. In addition, indices, scales and questionnaires of activity, muscle involvement, damage, disability, and quality of life will be determined. The recruitment period will be 23 months. The purpose is to obtain a cohort of 400 patients with IMM.

CONCLUSIONS

Myo-Spain registry provides the opportunity to develop a cohort of incident and prevalent patients with IMM in Spain. Myo-Spain will be able to assess in detail the clinical characteristics of the disease at different times. The comprehensive information collected during the visits is expected to provide a broad source of data for future analysis.

Interferon-signature in idiopathic inflammatory myopathies

PURPOSE OF REVIEW

The present review describes the interferon (IFN)-signature currently emerging as a tool for the diagnosis of idiopathic inflammatory myopathies (IIMs), and aims at presenting the interests and limitations of this recent tool for the clinics and the research.

RECENT FINDINGS

Recent in-vivo and in-vitro transcriptomic studies have evidenced the involvement of IFNs in the pathogenesis of IIMs. A correlation between the IFN-signature and the clinical severity of IIMs has been established. Moreover, studies pointed out differences in the IFN-signature regarding the IIM subgroup (dermatomyositis, polymyositis, inclusion body myositis, anti-synthetase syndrome, immuno-mediated necrotizing myopathies), raising the hypothesis of several pathogenic processes in IIMs.

SUMMARY

IIM pathogenesis remains partially understood. IFN-signature represents one of the main recent advances in the field. IFN-signature was identified thanks to transcriptomic analyses of tissues or cells from IIM patients (muscle, skin, blood cells, muscle cells) and should allow to establish new diagnosis and better monitoring of IIM patients. It also provides a tool for investigation of IIM pathogenesis. Nevertheless, IFN-signature still requires accurate definition in order to standardize its use, notably in the clinical practice.

Edematous myositis: a clinical presentation first suggesting dermatomyositis diagnosis

AIMS

Edema of the limbs is uncommon in idiopathic inflammatory myopathies (IIM). The few reported cases have been associated with severe and refractory dermatomyositis (DM), sometimes in association with cancers. We aimed to determine if edematous myositis is a homogeneous subtype based on clinical, serological and pathological features.

METHODS

This is a retrospective observational study performed between 2008 and 2015 in the French national referral center for myositis. All adult patients with an inflammatory muscle biopsy and upper limbs edema were included as well as IIM cases without limb edema as controls. Clinical, biological and pathological features were collected.

RESULTS

Seventeen edematous myositis were included and compared to 174 IIM without edema, including 50 DM controls. Edema was the first manifestation in 23% of patients. Muscle weakness was severe and symmetric, 71% of patients presented dysphagia and a restrictive ventilatory pattern was found in 40%. Fifty-two percent of patients had a typical DM skin rash and 23% had cancer within 3 years of diagnosing myositis. Fifty-three percent of patients presented a myositis specific antibody and only DM-specific antibodies were detected. Classic pathological DM features (perifascicular atrophy, perifascicular/perimysial perivascular inflammation) were uncommon but capillary C5b-9 deposition and MxA expression were seen in 79% and 73% of cases, respectively. A perimysial edema was found in 82% of cases. Seventeen percent of patients died (median follow up of 18 months). Edematous myositis demonstrated more marked capillary C5b-9 deposition compared to IIM controls. There was no clinical, biological or pathological difference with DM controls except for limb edema.

CONCLUSION

Our study underlines that limb edema could be a symptom of IIM and that edematous myositis are mostly DM. The vasculopathy seems to play a key role in its pathophysiology. Limb edema associated with muscle impairment should suggest the diagnosis of DM in clinical settings.

Update on outcome assessment in myositis

The adult and juvenile myositis syndromes, commonly referred to collectively as idiopathic inflammatory myopathies (IIMs), are systemic autoimmune diseases with the hallmarks of muscle weakness and inflammation. Validated, well-standardized measures to assess disease activity, known as core set measures, were developed by international networks of myositis researchers for use in clinical trials. Composite response criteria using weighted changes in the core set measures of disease activity were developed and validated for adult and juvenile patients with dermatomyositis and adult patients with polymyositis, with different thresholds for minimal, moderate and major improvement in adults and juveniles. Additional measures of muscle strength and function are being validated to improve content validity and sensitivity to change. A health-related quality of life measure, which incorporates patient input, is being developed for adult patients with IIM. Disease state criteria, including criteria for inactive disease and remission, are being used as secondary end points in clinical trials. MRI of muscle and immunological biomarkers are promising approaches to discriminate between disease activity and damage and might provide much-needed objective outcome measures. These advances in the assessment of outcomes for myositis treatment, along with collaborations between international networks, should facilitate further development of new therapies for patients with IIM.

Early detection of myocardial involvement by T1 mapping of cardiac MRI in idiopathic inflammatory myopathy

BACKGROUND

Polymyositis (PM) and dermatomyositis (DM) are common types of idiopathic inflammatory myopathy (IIM), wherein patients are prone to adverse cardiovascular events.

PURPOSE

To explore the value of cardiac magnetic resonance imaging (MRI) for detecting cardiac involvement in PM/DM patients using a T₁ mapping technique.

STUDY TYPE

Prospective observational study.

POPULATION

In all, 25 PM/DM patients free of cardiovascular symptoms and preserved ventricular systolic function and 25 healthy volunteers matched for age and sex served as controls.

FIELD STRENGTH/SEQUENCE

Cardiac MRI at 3T, including steady-state free precession (SSFP) cine imaging, late gadolinium enhancement (LGE), and T₁ mapping with modified Look-Locker inversion recovery (MOLLI).

ASSESSMENT

Myocardial native T₁ and extracellular volume (ECV) of the left ventricle as well as the correlations with disease activity were analyzed.

STATISTICAL TESTS

Independent sample's t-test, Fisher's exact test, or chi-square test, Pearson's correlation (r) were applied. P ≤ 0.05 was considered significant.

RESULTS

Left ventricular end-diastolic/end-systolic volume index (P = 0.643, P = 0.325, respectively), mass index (P = 0.719), and ejection fraction (P = 0.144) were not significantly different between PM/DM patients and controls. LGE was found in 19% of PM/DM patients and none of the control subjects. PM/DM patients showed significantly higher native T₁ values (1263.7 ± 84.0 msec vs. 1200.6 ± 43.0 msec, P = 0.002) and expanded extracellular volume (ECV) (32.6 ± 3.7% vs. 26.7 ± 2.3%, P < 0.001) compared with control subjects. ECV values in PM/DM patients had a high proportion (60%) over the 95% percentile of normal controls. Meanwhile, there was a significant correlation between native T₁ (r = 0.710, P = 0.0001) or ECV (r = 0.508, P = 0.01) and N-terminal prohormone of brain natriuretic peptide (NT-proBNP).

DATA CONCLUSION

T₁ mapping of cardiac MRI is valuable to detect subclinical myocardial involvement in PM/DM patients, and both myocardial native T₁ and ECV could serve as early imaging markers for myocardial impairment in PM/DM.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 3 J. MAGN. RESON. IMAGING 2018;48:415-422.

[Focal myositis: An unknown disease]

Focal myositis are inflammatory muscle diseases of unknown origin. At the opposite from the other idiopathic inflammatory myopathies, they are restricted to a single muscle or to a muscle group. They are not associated with extramuscular manifestations, and they have a good prognosis without any treatment. They are characterized by a localized swelling affecting mostly lower limbs. The pseudo-tumor can be painful, but is not associated with a muscle weakness. Creatine kinase level is normal. Muscle MRI shows an inflammation restricted to a muscle or a muscle group. Muscle biopsy and pathological analysis remain necessary for the diagnosis, showing inflammatory infiltrates composed by macrophages and lymphocytes without any specific distribution within the muscle. Focal overexpression of HLA-1 by the muscle fibers is frequently observed. The muscle biopsy permits to rule out differential diagnosis such a malignancy (sarcoma). Spontaneous remission occurs within weeks or months after the first symptoms, relapse is unusual.

Predictors of Reduced Health-Related Quality of Life in Adult Patients With Idiopathic Inflammatory Myopathies

OBJECTIVE

Extensive studies on health-related quality of life (HRQoL) in idiopathic inflammatory myopathies (IIMs) are lacking. Our objective was to document HRQoL and to identify factors associated with a reduced HRQoL in patients with IIM.

METHODS

A total of 1,715 patients (median age 49.9 years, 70% female, 87% white) who met probable or definite Bohan and Peter criteria or Griggs criteria for myositis were included from the Myovision registry. HRQoL was ascertained using the Short Form 12 (SF-12) health survey questionnaire. HRQoL physical component summary (PCS) and mental component summary (MCS) scores in relation to different patient and disease characteristics were compared to scores from matched normative data from the US general population and rheumatoid arthritis (RA) patients. Bivariate and multiple linear regression analyses were performed to assess the association between HRQoL and patient and disease parameters.

RESULTS

The mean SF-12 summary scores were significantly lower in IIM patients than in the normative and RA populations. A diagnosis of inclusion body myositis, older age, patient-reported negative effect of disease on work, presence of another co-occurring autoimmune disease, polypharmacy, and IIM-associated lung disease and joint involvement were significantly associated with lower PCS scores. Lower MCS scores were associated with joint involvement and a negative effect of disease on work.

CONCLUSION

In this large study of patient-reported outcomes in IIM, an association was found between multiple disease characteristics and reduced HRQoL, mostly in the physical domain. In the US, the HRQoL of IIM patients was found to be lower than that of the general population and RA patients.

Clinicopathologic features of myositis patients with CD8-MHC-1 complex pathology

Objective:

To determine the clinical features of myositis patients with the histopathologic finding of CD8-positive T cells invading non-necrotic muscle fibers expressing major histocompatibility complex class 1 (CD8-MHC-1 complex), which is shared by polymyositis (PM) and inclusion body myositis (IBM), in relation to the p62 immunostaining pattern of muscle fibers.

Methods:

All 93 myositis patients with CD8-MHC-1 complex who were referred to our hospital from 1993 to 2015 were classified on the basis of the European Neuromuscular Center (ENMC) diagnostic criteria for IBM (Rose, 2013) or PM (Hoogendijk, 2004) and analyzed.

Results:

The 93 patients included were 17 patients with PM, 70 patients with IBM, and 6 patients who neither met the criteria for PM nor IBM in terms of muscle weakness distribution (unclassifiable group). For these PM, IBM, and unclassifiable patients, their mean ages at diagnosis were 63, 70, and 64 years; autoimmune disease was present in 7 (41%), 13 (19%), and 4 (67%); hepatitis C virus infection was detected in 0%, 13 (20%), and 2 (33%); and p62 was immunopositive in 0%, 66 (94%), and 2 (33%), respectively. Of the treated patients, 11 of 16 PM patients and 4 of 6 p62-immunonegative patients in the unclassifiable group showed responses to immunotherapy, whereas all 44 patients with IBM and 2 p62-immunopositive patients in the unclassifiable group were unresponsive to immunotherapy.

Conclusions:

CD8-MHC-1 complex is present in patients with PM, IBM, or unclassifiable group. The data may serve as an argument for a trial of immunosuppressive treatment in p62-immunonegative patients with unclassifiable myositis.

Toll-Like Receptor 4-Myeloid Differentiation Primary Response Gene 88 Pathway Is Involved in the Inflammatory Development of Polymyositis by Mediating Interferon-γ and Interleukin-17A in Humans and Experimental Autoimmune Myositis Mouse Model

OBJECTIVE

Toll-like receptor 4 (TLR4) is one of the key players in the development of many autoimmune diseases. To determine the possible role of TLR4 in polymyositis (PM) development, we collected muscle samples from PM patients and mice subjected to an experimental autoimmune myositis (EAM) model.

METHODS

We measured TLR4-MyD88 pathway-related factors, interferon-γ (IFN-γ), and interleukin-17A (IL-17A) in EAM mice and PM patients. Then, we observed the changes of above factors and the inflammatory development of EAM mice with TLR4 antagonist TAK-242, IFN-γ, or IL-17A antibody treatment.

RESULTS

The expression of TLR4, MyD88, and NF-κB was significantly upregulated in the muscle tissues both in 22 patients with PM and in the EAM model. As expected, increased levels of various cytokines, such as IL-1β, IL-6, IL-10, IL-12, tumor necrosis factor-α, TGF-β, IFN-γ, and IL-17A, were evident in the serum of EAM mice. Moreover, mRNA expression levels of IFN-γ and IL-17A were significantly increased in both PM patients and EAM mice. Consistently, the levels of these factors were positively correlated with the degree of muscle inflammation in EAM mice. However, when EAM mice were treated with TLR4 antagonist TAK-242, the expression of IFN-γ and IL-17A was decreased. When the cytokines were neutralized by anti-IFN-γ or anti-IL-17A antibody, the inflammatory development of EAM exacerbated or mitigated.

CONCLUSION

The present study provided the important evidence that the TLR4-MyD88 pathway may be involved in the immune mechanisms of PM by mediating IFN-γ and IL-17A.

Submaximal Exercise Capacity in Juvenile Dermatomyositis after Longterm Disease: The Contribution of Muscle, Lung, and Heart Involvement

OBJECTIVE

To compare submaximal exercise capacity in patients with juvenile dermatomyositis (JDM) with controls, and analyze contributions of muscle, heart, and lung impairment in patients.

METHODS

Fifty-nine patients with JDM, with a mean 16.9 years after symptom onset, and 59 sex- and age-matched controls completed a 6-min walk test (6MWT) and a timed up and go (TUG) test. Muscle function, disease activity/damage, and health-related quality of life (HRQOL) were assessed by validated tools; heart function by echocardiography and electrocardiography; and lung function by spirometry, DLCO, and body plethysmography. A thoracic high-resolution computed tomography (HRCT) scan and magnetic resonance imaging of the thighs were completed in patients.

RESULTS

The 6MWT distance (6MWD) was 592 ± 81 m in patients versus 649 ± 79 m in controls (p < 0.001), and 563 ± 75 m in active versus 622 ± 76 m in inactive JDM (p = 0.004). The TUG time was 13.1 ± 2.1 s in patients versus 12.3 ± 2.0 s in controls (p = 0.034), and 13.7 ± 2.2 s in active versus 12.5 ± 1.8 s in inactive JDM (p = 0.028). No statistically significant difference was found between inactive JDM and controls in either test. In patients, the Childhood Myositis Assessment Score influenced the 6MWD and TUG time the most, followed by a low DLCO and HRCT pathology in the 6MWT and forced vital capacity in the TUG test. Medical Outcomes Study Short Form-36 physical component summary correlated strongly with both tests.

CONCLUSION

Submaximal exercise capacity was reduced in patients with JDM, particularly those with active disease. This reduction was associated with muscle and lung dysfunction and poorer HRQOL.