International consensus on preliminary definitions of improvement in adult and juvenile myositis

Current diagnosis and treatment of polymyositis and dermatomyositis

Idiopathic inflammatory myopathies (IIMs) are heterogeneous disorders that affect the skeletal muscles. Polymyositis, dermatomyositis, and inclusion body myositis are major IIM subsets. Immune-mediated necrotizing myopathy became recognized as a potentially new IIM subset. Since the new classification criteria published by the International Myositis Classification Criteria Project have higher sensitivity and specificity for IIM classification and subclassification than the previous criteria, they should help precise diagnosis. It should be noted that several tests available in current clinical practice, such as electromyography, magnetic resonance imaging, and other myositis-specific autoantibodies than anti-Jo-1 antibodies, were not included in the new criteria. As for treatment, glucocorticoids are used empirically as the first-line treatment despite their various adverse effects. Concomitant treatment with steroid-sparing immunosuppressive agents, including methotrexate, azathioprine, calcineurin inhibitors, mycophenolate mofetil, and cyclophosphamide, reduces successfully initial glucocorticoid doses for the remission induction, the relapse risk during glucocorticoid tapering, and adverse effects of glucocorticoids. Treatment with biologics, including rituximab and abatacept, seems promising in some IIM patients. Multi-target treatment with glucocorticoids and several steroid-sparing immunosuppressive agents is effective in refractory IIM patients. Considering proven steroid-sparing efficacy and tolerability of multi-target treatment in patients with other autoimmune diseases, it should be a good therapeutic option for IIMs.

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.

Innovative Research Design to Meet the Challenges of Clinical Trials for Juvenile Dermatomyositis

PURPOSE OF REVIEW

This paper aims to provide a summary of the recent therapeutic advances and the latest research on outcome measures for clinical trials in juvenile dermatomyositis (JDM).

RECENT FINDINGS

Recent randomized controlled trials (RCTs) have demonstrated the superiority of the combination of prednisone with methotrexate over other conventional therapies and the potential effectiveness of rituximab in refractory cases. A multinational project has led to develop new criteria for the definition of minimal, moderate, and major improvement in future JDM clinical trials. This effort has been paralleled by the establishment of criteria for clinically inactive disease. The validation of the first composite disease activity score for JDM is in progress. The new outcome measures will increase the reliability of assessment of clinical response in JDM clinical trials and foster future multinational RCTs aimed to investigate novel treatment strategies for refractory forms of JDM.

Manual muscle testing and hand-held dynamometry in people with inflammatory myopathy: An intra- and interrater reliability and validity study

Manual muscle testing (MMT) and hand-held dynamometry (HHD) are commonly used in people with inflammatory myopathy (IM), but their clinimetric properties have not yet been sufficiently studied. To evaluate the reliability and validity of MMT and HHD, maximum isometric strength was measured in eight muscle groups across three measurement events. To evaluate reliability of HHD, intra-class correlation coefficients (ICC), the standard error of measurements (SEM) and smallest detectable changes (SDC) were calculated. To measure reliability of MMT linear Cohen`s Kappa was computed for single muscle groups and ICC for total score. Additionally, correlations between MMT8 and HHD were evaluated with Spearman Correlation Coefficients. Fifty people with myositis (56±14 years, 76% female) were included in the study. Intra-and interrater reliability of HHD yielded excellent ICCs (0.75–0.97) for all muscle groups, except for interrater reliability of ankle extension (0.61). The corresponding SEMs% ranged from 8 to 28% and the SDCs% from 23 to 65%. MMT8 total score revealed excellent intra-and interrater reliability (ICC>0.9). Intrarater reliability of single muscle groups was substantial for shoulder and hip abduction, elbow and neck flexion, and hip extension (0.64–0.69); moderate for wrist (0.53) and knee extension (0.49) and fair for ankle extension (0.35). Interrater reliability was moderate for neck flexion (0.54) and hip abduction (0.44); fair for shoulder abduction, elbow flexion, wrist and ankle extension (0.20–0.33); and slight for knee extension (0.08). Correlations between the two tests were low for wrist, knee, ankle, and hip extension; moderate for elbow flexion, neck flexion and hip abduction; and good for shoulder abduction. In conclusion, the MMT8 total score is a reliable assessment to consider general muscle weakness in people with myositis but not for single muscle groups. In contrast, our results confirm that HHD can be recommended to evaluate strength of single muscle groups.

2016 ACR-EULAR adult dermatomyositis and polymyositis and juvenile dermatomyositis response criteria-methodological aspects

Objective

The objective was to describe the methodology used to develop new response criteria for adult DM/PM and JDM.

Methods

Patient profiles from prospective natural history data and clinical trials were rated by myositis specialists to develop consensus gold-standard ratings of minimal, moderate and major improvement. Experts completed a survey regarding clinically meaningful improvement in the core set measures (CSM) and a conjoint-analysis survey (using 1000Minds software) to derive relative weights of CSM and candidate definitions. Six types of candidate definitions for response criteria were derived using survey results, logistic regression, conjoint analysis, application of conjoint-analysis weights to CSM and published definitions. Sensitivity, specificity and area under the curve were defined for candidate criteria using consensus patient profile data, and selected definitions were validated using clinical trial data.

Results

Myositis specialists defined the degree of clinically meaningful improvement in CSM for minimal, moderate and major improvement. The conjoint-analysis survey established the relative weights of CSM, with muscle strength and Physician Global Activity as most important. Many candidate definitions showed excellent sensitivity, specificity and area under the curve in the consensus profiles. Trial validation showed that a number of candidate criteria differentiated between treatment groups. Top candidate criteria definitions were presented at the consensus conference.

Conclusion

Consensus methodology, with definitions tested on patient profiles and validated using clinical trials, led to 18 definitions for adult PM/DM and 14 for JDM as excellent candidates for consideration in the final consensus on new response criteria for myositis.

2017 European League Against Rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups

OBJECTIVE

To develop and validate new classification criteria for adult and juvenile idiopathic inflammatory myopathies (IIM) and their major subgroups.

METHODS

Candidate variables were assembled from published criteria and expert opinion using consensus methodology. Data were collected from 47 rheumatology, dermatology, neurology and paediatric clinics worldwide. Several statistical methods were used to derive the classification criteria.

RESULTS

Based on data from 976 IIM patients (74% adults; 26% children) and 624 non-IIM patients with mimicking conditions (82% adults; 18% children), new criteria were derived. Each item is assigned a weighted score. The total score corresponds to a probability of having IIM. Subclassification is performed using a classification tree. A probability cut-off of 55%, corresponding to a score of 5.5 (6.7 with muscle biopsy) 'probable IIM', had best sensitivity/specificity (87%/82% without biopsies, 93%/88% with biopsies) and is recommended as a minimum to classify a patient as having IIM. A probability of ≥90%, corresponding to a score of ≥7.5 (≥8.7 with muscle biopsy), corresponds to 'definite IIM'. A probability of <50%, corresponding to a score of <5.3 (<6.5 with muscle biopsy), rules out IIM, leaving a probability of ≥50 to <55% as 'possible IIM'.

CONCLUSIONS

The European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for IIM have been endorsed by international rheumatology, dermatology, neurology and paediatric groups. They employ easily accessible and operationally defined elements, and have been partially validated. They allow classification of 'definite', 'probable' and 'possible' IIM, in addition to the major subgroups of IIM, including juvenile IIM. They generally perform better than existing criteria.

2017 European League Against Rheumatism/American College of Rheumatology Classification Criteria for Adult and Juvenile Idiopathic Inflammatory Myopathies and Their Major Subgroups

OBJECTIVE

To develop and validate new classification criteria for adult and juvenile idiopathic inflammatory myopathies (IIM) and their major subgroups.

METHODS

Candidate variables were assembled from published criteria and expert opinion using consensus methodology. Data were collected from 47 rheumatology, dermatology, neurology, and pediatric clinics worldwide. Several statistical methods were utilized to derive the classification criteria.

RESULTS

Based on data from 976 IIM patients (74% adults; 26% children) and 624 non-IIM patients with mimicking conditions (82% adults; 18% children), new criteria were derived. Each item is assigned a weighted score. The total score corresponds to a probability of having IIM. Subclassification is performed using a classification tree. A probability cutoff of 55%, corresponding to a score of 5.5 (6.7 with muscle biopsy) "probable IIM," had best sensitivity/specificity (87%/82% without biopsies, 93%/88% with biopsies) and is recommended as a minimum to classify a patient as having IIM. A probability of ≥90%, corresponding to a score of ≥7.5 (≥8.7 with muscle biopsy), corresponds to "definite IIM." A probability of <50%, corresponding to a score of <5.3 (<6.5 with muscle biopsy), rules out IIM, leaving a probability of ≥50-<55% as "possible IIM."

CONCLUSION

The European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for IIM have been endorsed by international rheumatology, dermatology, neurology, and pediatric groups. They employ easily accessible and operationally defined elements, and have been partially validated. They allow classification of "definite," "probable," and "possible" IIM, in addition to the major subgroups of IIM, including juvenile IIM. They generally perform better than existing criteria.

Muscle involvement in systemic sclerosis: points to consider in clinical trials

SSc is clinically and pathogenetically heterogeneous. Consensus standards for trial design and outcome measures are needed. International experts experienced in SSc clinical trial design and a researcher experienced in systematic literature review screened the PubMed and Cochrane Central Register of Controlled Trials in order to develop points to consider when planning a clinical trial for muscle involvement in SSc. The experts conclude that SSc-associated muscle involvement is heterogeneous and lacks a universally accepted gold-standard for measuring therapeutic response. Although outcome studies are currently limited by the inability to clearly distinguish active, reversible muscle inflammation from irreversible muscle damage and extramuscular organ involvement, strong consideration should be given to enrolling patients with a myopathy that features several elements of likely reversibility such as muscle weakness, biopsy-proven active inflammation, an MRI indicating muscle inflammation and a baseline serum creatinine kinase above three times the upper limit of normal to prevent floor effect. Randomized controlled trials are preferred, with a duration of at least 24 weeks. Outcome measures should include a combination of elements that are likely to be reversible, such as muscle weakness, biopsy-proven active inflammation, creatinine kinase/aldolase and a quality of life questionnaire. The individual measurements might require a short pre-study for further validation. A biological sample repository is recommended.

Abatacept in the treatment of adult dermatomyositis and polymyositis: a randomised, phase IIb treatment delayed-start trial

OBJECTIVES

To study the effects of abatacept on disease activity and on muscle biopsy features of adult patients with dermatomyositis (DM) or polymyositis (PM).

METHODS

Twenty patients with DM (n=9) or PM (n=11) with refractory disease were enrolled in a randomised treatment delayed-start trial to receive either immediate active treatment with intravenous abatacept or a 3 month delayed-start. The primary endpoint was number of responders, defined by the International Myositis Assessment and Clinical Studies Group definition of improvement (DOI), after 6 months of treatment. Secondary endpoints included number of responders in the early treatment arm compared with the delayed treatment arm at 3 months. Repeated muscle biopsies were investigated for cellular markers and cytokines.

RESULTS

8/19 patients included in the analyses achieved the DOI at 6 months. At 3 months of study, five (50%) patients were responders after active treatment but only one (11%) patient in the delayed treatment arm. Eight adverse events (AEs) were regarded as related to the drug, four mild and four moderate, and three serious AEs, none related to the drug. There was a significant increase in regulatory T cells (Tregs), whereas other markers were unchanged in repeated muscle biopsies.

CONCLUSIONS

In this pilot study, treatment of patients with DM and PM with abatacept resulted in lower disease activity in nearly half of the patients. In patients with repeat muscle biopsies, an increased frequency of Foxp3⁺ Tregs suggests a positive effect of treatment in muscle tissue.

Treatment of Juvenile Dermatomyositis: An Update

The idiopathic inflammatory myopathies of childhood consist of a heterogeneous group of autoimmune diseases characterised by proximal muscle weakness and pathognomonic skin rashes. The overall prognosis of juvenile myositis has improved significantly over recent years, but the long-term outcome differs substantially from patient to patient, suggestive of distinct clinical phenotypes with variable responses to treatment. High doses of corticosteroids remain the cornerstone of therapy along with other immunosuppressant therapies depending on disease severity and response. The advent of biological drugs has revolutionised the management of various paediatric rheumatologic diseases, including inflammatory myopathies. There are few data from randomised controlled trials to guide management decisions; thus, several algorithms for the treatment of juvenile myositis have been developed using international expert opinion. The general treatment goals now include elimination of active disease and normalisation of physical function, so as to preserve normal growth and development, and to prevent long-term damage and deformities. This review summarises the newer and possible future therapies of juvenile inflammatory myopathies, including evidence supporting their efficacy and safety.

The COMET Handbook: version 1.0

The selection of appropriate outcomes is crucial when designing clinical trials in order to compare the effects of different interventions directly. For the findings to influence policy and practice, the outcomes need to be relevant and important to key stakeholders including patients and the public, health care professionals and others making decisions about health care. It is now widely acknowledged that insufficient attention has been paid to the choice of outcomes measured in clinical trials. Researchers are increasingly addressing this issue through the development and use of a core outcome set, an agreed standardised collection of outcomes which should be measured and reported, as a minimum, in all trials for a specific clinical area.Accumulating work in this area has identified the need for guidance on the development, implementation, evaluation and updating of core outcome sets. This Handbook, developed by the COMET Initiative, brings together current thinking and methodological research regarding those issues. We recommend a four-step process to develop a core outcome set. The aim is to update the contents of the Handbook as further research is identified.

2016 American College of Rheumatology/European League Against Rheumatism Criteria for Minimal, Moderate, and Major Clinical Response in Juvenile Dermatomyositis: An International Myositis Assessment and Clinical Studies Group/Paediatric Rheumatology International Trials Organisation Collaborative Initiative

OBJECTIVE

To develop response criteria for juvenile dermatomyositis (DM).

METHODS

We analyzed the performance of 312 definitions that used core set measures from either the International Myositis Assessment and Clinical Studies Group (IMACS) or the Paediatric Rheumatology International Trials Organisation (PRINTO) and were derived from natural history data and a conjoint analysis survey. They were further validated using data from the PRINTO trial of prednisone alone compared to prednisone with methotrexate or cyclosporine and the Rituximab in Myositis (RIM) trial. At a consensus conference, experts considered 14 top candidate criteria based on their performance characteristics and clinical face validity, using nominal group technique.

RESULTS

Consensus was reached for a conjoint analysis-based continuous model with a total improvement score of 0-100, using absolute percent change in core set measures of minimal (≥30), moderate (≥45), and major (≥70) improvement. The same criteria were chosen for adult DM/polymyositis, with differing thresholds for improvement. The sensitivity and specificity were 89% and 91-98% for minimal improvement, 92-94% and 94-99% for moderate improvement, and 91-98% and 85-86% for major improvement, respectively, in juvenile DM patient cohorts using the IMACS and PRINTO core set measures. These criteria were validated in the PRINTO trial for differentiating between treatment arms for minimal and moderate improvement (P = 0.009-0.057) and in the RIM trial for significantly differentiating the physician's rating for improvement (P < 0.006).

CONCLUSION

The response criteria for juvenile DM consisted of a conjoint analysis-based model using a continuous improvement score based on absolute percent change in core set measures, with thresholds for minimal, moderate, and major improvement.

2016 American College of Rheumatology/European League Against Rheumatism Criteria for Minimal, Moderate, and Major Clinical Response in Juvenile Dermatomyositis: An International Myositis Assessment and Clinical Studies Group/Paediatric Rheumatology International Trials Organisation Collaborative Initiative

To develop response criteria for juvenile dermatomyositis (DM). We analysed the performance of 312 definitions that used core set measures from either the International Myositis Assessment and Clinical Studies Group (IMACS) or the Paediatric Rheumatology International Trials Organisation (PRINTO) and were derived from natural history data and a conjoint analysis survey. They were further validated using data from the PRINTO trial of prednisone alone compared to prednisone with methotrexate or cyclosporine and the Rituximab in Myositis (RIM) trial. At a consensus conference, experts considered 14 top candidate criteria based on their performance characteristics and clinical face validity, using nominal group technique. Consensus was reached for a conjoint analysis-based continuous model with a total improvement score of 0-100, using absolute per cent change in core set measures of minimal (≥30), moderate (≥45), and major (≥70) improvement. The same criteria were chosen for adult DM/polymyositis, with differing thresholds for improvement. The sensitivity and specificity were 89% and 91-98% for minimal improvement, 92-94% and 94-99% for moderate improvement, and 91-98% and 85-86% for major improvement, respectively, in juvenile DM patient cohorts using the IMACS and PRINTO core set measures. These criteria were validated in the PRINTO trial for differentiating between treatment arms for minimal and moderate improvement (p=0.009-0.057) and in the RIM trial for significantly differentiating the physician's rating for improvement (p<0.006). The response criteria for juvenile DM consisted of a conjoint analysis-based model using a continuous improvement score based on absolute per cent change in core set measures, with thresholds for minimal, moderate, and major improvement.

2016 American College of Rheumatology/European League Against Rheumatism criteria for minimal, moderate, and major clinical response in adult dermatomyositis and polymyositis: An International Myositis Assessment and Clinical Studies Group/Paediatric Rheumatology International Trials Organisation Collaborative Initiative

To develop response criteria for adult dermatomyositis (DM) and polymyositis (PM). Expert surveys, logistic regression, and conjoint analysis were used to develop 287 definitions using core set measures. Myositis experts rated greater improvement among multiple pairwise scenarios in conjoint analysis surveys, where different levels of improvement in 2 core set measures were presented. The PAPRIKA (Potentially All Pairwise Rankings of All Possible Alternatives) method determined the relative weights of core set measures and conjoint analysis definitions. The performance characteristics of the definitions were evaluated on patient profiles using expert consensus (gold standard) and were validated using data from a clinical trial. The nominal group technique was used to reach consensus. Consensus was reached for a conjoint analysis-based continuous model using absolute per cent change in core set measures (physician, patient, and extramuscular global activity, muscle strength, Health Assessment Questionnaire, and muscle enzyme levels). A total improvement score (range 0-100), determined by summing scores for each core set measure, was based on improvement in and relative weight of each core set measure. Thresholds for minimal, moderate, and major improvement were ≥20, ≥40, and ≥60 points in the total improvement score. The same criteria were chosen for juvenile DM, with different improvement thresholds. Sensitivity and specificity in DM/PM patient cohorts were 85% and 92%, 90% and 96%, and 92% and 98% for minimal, moderate, and major improvement, respectively. Definitions were validated in the clinical trial analysis for differentiating the physician rating of improvement (p<0.001). The response criteria for adult DM/PM consisted of the conjoint analysis model based on absolute per cent change in 6 core set measures, with thresholds for minimal, moderate, and major improvement.

2016 American College of Rheumatology/European League Against Rheumatism Criteria for Minimal, Moderate, and Major Clinical Response in Adult Dermatomyositis and Polymyositis: An International Myositis Assessment and Clinical Studies Group/Paediatric Rheumatology International Trials Organisation Collaborative Initiative

OBJECTIVE

To develop response criteria for adult dermatomyositis (DM) and polymyositis (PM).

METHODS

Expert surveys, logistic regression, and conjoint analysis were used to develop 287 definitions using core set measures. Myositis experts rated greater improvement among multiple pairwise scenarios in conjoint analysis surveys, where different levels of improvement in 2 core set measures were presented. The PAPRIKA (Potentially All Pairwise Rankings of All Possible Alternatives) method determined the relative weights of core set measures and conjoint analysis definitions. The performance characteristics of the definitions were evaluated on patient profiles using expert consensus (gold standard) and were validated using data from a clinical trial. The nominal group technique was used to reach consensus.

RESULTS

Consensus was reached for a conjoint analysis-based continuous model using absolute percent change in core set measures (physician, patient, and extramuscular global activity, muscle strength, Health Assessment Questionnaire, and muscle enzyme levels). A total improvement score (range 0-100), determined by summing scores for each core set measure, was based on improvement in and relative weight of each core set measure. Thresholds for minimal, moderate, and major improvement were ≥20, ≥40, and ≥60 points in the total improvement score. The same criteria were chosen for juvenile DM, with different improvement thresholds. Sensitivity and specificity in DM/PM patient cohorts were 85% and 92%, 90% and 96%, and 92% and 98% for minimal, moderate, and major improvement, respectively. Definitions were validated in the clinical trial analysis for differentiating the physician rating of improvement (P < 0.001).

CONCLUSION

The response criteria for adult DM/PM consisted of the conjoint analysis model based on absolute percent change in 6 core set measures, with thresholds for minimal, moderate, and major improvement.

Physical function and muscle strength in sporadic inclusion body myositis

INTRODUCTION

In this study, self-reported physical function, functional capacity, and isolated muscle function were investigated in sporadic inclusion body myositis (sIBM) patients.

METHODS

The 36-item Short Form (SF-36) Health Survey and 2-min walk test (2MWT), timed up & go test (TUG), and 30-s chair stand performance were evaluated. In addition, patients were tested for knee extensor muscle strength (isokinetic dynamometer) and leg extension power (Nottingham power rig).

RESULTS

TUG performance was the strongest predictor of self-reported physical function (r² = 0.56, P < 0.05). Knee extension strength and between-limb strength asymmetry were the strongest multi-regression indicators of TUG performance (r² = 0.51, P < 0.05). Strength asymmetry showed the strongest single-factor (negative) association with 2MWT performance (r² = 0.49, P < 0.05).

DISCUSSION

TUG assessment appears to sensitively predict self-perceived physical function in sIBM patients. Notably, between-limb asymmetry in lower limb muscle strength had a substantial negative impact on motor tasks involving gait function. Muscle Nerve 56: E50-E58, 2017.

Clinical characteristics of anti-SAE antibodies in Chinese patients with dermatomyositis in comparison with different patient cohorts

This study aimed to analyze the clinical features of anti-SAE antibodies in Chinese myositis patients in comparison with different cohorts. The anti-SAE antibodies were tested in myositis patients and in control subjects. Long-term follow-up was conducted on the antibody-positive patients. Anti-SAE antibodies were exclusively present in 12 out of 394 (3.0%) adult dermatomyositis (DM) patients. Of the anti-SAE-positive DM patients, 75% had distinctive diffuse dark-red or pigment-like skin rashes, and 67% of these patients experienced mild muscle weakness. Muscular biopsies showed mild pathological manifestations. Compared with the antibody-negative group, the average age of dermatomyositis onset in the antibody-positive group was higher, and dysphagia occurred more frequently noted (p = 0.012). Only 9 patients received follow-up, 7 experienced improvement after treatment. The anti-SAE antibody levels correlated with improved disease condition. The anti-SAE antibody was found exclusively in adult DM patients, occurring infrequently in Chinese patients. In addition to a diffuse dark-red or pigment-like skin rash and mild muscular weakness, common symptoms included propensity for developing dysphagia. Serum levels of the anti-SAE antibody correlated with myositis disease activity, and anti-SAE-positive patients were responsive to treatment.

Autoantibody Specificities and Type I Interferon Pathway Activation in Idiopathic Inflammatory Myopathies

Myositis is a heterogeneous group of autoimmune diseases, with different pathogenic mechanisms contributing to the different subsets of disease. The aim of this study was to test whether the autoantibody profile in patients with myositis is associated with a type I interferon (IFN) signature, as in patients with systemic lupus erythematous (SLE). Patients with myositis were prospectively enrolled in the study and compared to healthy controls and to patients with SLE. Autoantibody status was analysed using an immunoassay system and immunoprecipitation. Type I IFN activity in whole blood was determined using direct gene expression analysis. Serum IFN-inducing activity was tested using peripheral blood cells from healthy donors. Blocking experiments were performed by neutralizing anti-IFNAR or anti-IFN-α antibodies. Patients were categorized into IFN high and IFN low based on an IFN score. Patients with autoantibodies against RNA-binding proteins had a higher IFN score compared to patients without these antibodies, and the IFN score was related to autoantibody multispecificity. Patients with dermatomyositis (DM) and inclusion body myositis (IBM) had a higher IFN score compared to the other subgroups. Serum type I IFN bioactivity was blocked by neutralizing anti-IFNAR or anti-IFN-α antibodies. To conclude, a high IFN score was not only associated with DM, as previously reported, and IBM, but also with autoantibody monospecificity against several RNA-binding proteins and with autoantibody multispecificity. These studies identify IFN-α in sera as a trigger for activation of the type I IFN pathway in peripheral blood and support IFN-α as a possible target for therapy in these patients.

Cutaneous improvement in refractory adult and juvenile dermatomyositis after treatment with rituximab

OBJECTIVE

The aim was to assess the efficacy of rituximab for the cutaneous manifestations of adult DM and JDM.

METHODS

Patients with refractory adult DM (n = 72) and JDM (n = 48) were treated with rituximab in a randomized placebo-phase-controlled trial [either rituximab early drug (week 0/1) or rituximab late arms (week 8/9), such that all subjects received study drug]. Stable concomitant therapy was allowed. Cutaneous disease activity was assessed using the Myositis Disease Activity Assessment Tool, which grades cutaneous disease activity on a visual analog scale. A myositis damage assessment tool, termed the Myositis Damage Index, was used to assess cutaneous damage. Improvement post-rituximab was evaluated in individual rashes as well as in cutaneous disease activity and damage scores. The χ² test, Student's paired t-test and Wilcoxon test were used for analysis.

RESULTS

There were significant improvements in cutaneous disease activity from baseline to the end of the trial after rituximab administration in both adult DM and JDM subsets. The cutaneous visual analog scale activity improved in adult DM (3.22-1.72, P = 0.0002) and JDM (3.26-1.56, P <0.0001), with erythroderma, erythematous rashes without secondary changes of ulceration or necrosis, heliotrope, Gottron sign and papules improving most significantly. Adult DM subjects receiving rituximab earlier in the trial demonstrated a trend for faster cutaneous response (20% relative improvement from baseline) compared with those receiving B cell depletion later (P = 0.052).

CONCLUSION

Refractory skin rashes in adult DM and JDM showed improvement after the addition of rituximab to the standard therapy in a clinical trial.

Comparison of the Utility and Validity of Three Scoring Tools to Measure Skin Involvement in Patients With Juvenile Dermatomyositis

Objective

To compare the abbreviated Cutaneous Assessment Tool (CAT), Disease Activity Score (DAS), and Myositis Intention to Treat Activity Index (MITAX) and correlate them with the physician's 10‐cm skin visual analog scale (VAS) in order to define which tool best assesses skin disease in patients with juvenile dermatomyositis.

Methods

A total of 71 patients recruited to the UK Juvenile Dermatomyositis Cohort and Biomarker Study were included and assessed for skin disease using the CAT, DAS, MITAX, and skin VAS. The Childhood Myositis Assessment Scale (CMAS), manual muscle testing of 8 groups (MMT8), muscle enzymes, inflammatory markers, and physician's global VAS were recorded. Relationships were evaluated using Spearman's correlations and predictors with linear regression. Interrater reliability was assessed using intraclass correlation coefficients.

Results

All 3 tools showed correlation with the physician's global VAS and skin VAS, with DAS skin showing the strongest correlation with skin VAS. DAS skin and CAT activity were inversely correlated with CMAS and MMT8, but these correlations were moderate. No correlations were found between the skin tools and inflammatory markers or muscle enzymes. DAS skin and CAT were the quickest to complete (mean ± SD 0.68 ± 0.1 minutes and 0.63 ± 0.1 minutes, respectively).

Conclusion

The 3 skin tools were quick and easy to use. The DAS skin correlated best with the skin VAS. The addition of CAT in a bivariate model containing the physician's global VAS was a statistically significant estimator of skin VAS score. We propose that there is scope for a new skin tool to be devised and tested, which takes into account the strengths of the 3 existing tools.

Consensus-based recommendations for the management of juvenile dermatomyositis

Background

In 2012, a European initiative called Single Hub and Access point for pediatric Rheumatology in Europe (SHARE) was launched to optimise and disseminate diagnostic and management regimens in Europe for children and young adults with rheumatic diseases. Juvenile dermatomyositis (JDM) is a rare disease within the group of paediatric rheumatic diseases (PRDs) and can lead to significant morbidity. Evidence-based guidelines are sparse and management is mostly based on physicians' experience. Consequently, treatment regimens differ throughout Europe.

Objectives

To provide recommendations for diagnosis and treatment of JDM.

Methods

Recommendations were developed by an evidence-informed consensus process using the European League Against Rheumatism standard operating procedures. A committee was constituted, consisting of 19 experienced paediatric rheumatologists and 2 experts in paediatric exercise physiology and physical therapy, mainly from Europe. Recommendations derived from a validated systematic literature review were evaluated by an online survey and subsequently discussed at two consensus meetings using nominal group technique. Recommendations were accepted if >80% agreement was reached.

Results

In total, 7 overarching principles, 33 recommendations on diagnosis and 19 recommendations on therapy were accepted with >80% agreement among experts. Topics covered include assessment of skin, muscle and major organ involvement and suggested treatment pathways.

Conclusions

The SHARE initiative aims to identify best practices for treatment of patients suffering from PRD. Within this remit, recommendations for the diagnosis and treatment of JDM have been formulated by an evidence-informed consensus process to produce a standard of care for patients with JDM throughout Europe.

Critical review of the role of intravenous immunoglobulins in idiopathic inflammatory myopathies

OBJECTIVE

The aim of this review was to summarize key findings from the literature concerning the therapeutic role of intravenous immunoglobulins (IVIg) in idiopathic inflammatory myopathies (IIM), dissecting the evidence according to disease subtype and treatment indication, and to review the evidence relating to the mechanism of action of IVIg in IIM to ascertain rationale for continued research.

METHODS

Medline (Ovid) and Pubmed databases were searched from inception to July 2016 using relevant keywords. Original and review articles were retrieved for full-text review. Bibliographies of selected articles were also hand-searched for additional references. Data were summarized qualitatively and in tabular form.

RESULTS

The efficacy of IVIg in IIM is supported by 3 randomized controlled trials, involving dermatomyositis and polymyositis subjects, in refractory, relapsed, or steroid-dependent disease, as well as part of first-line therapy in elderly dermatomyositis subjects. Other indications for IVIg are supported by uncontrolled evidence only. Limitations of studies include open, uncontrolled or retrospective study designs, small and selected samples, short-term follow-up and ad hoc outcome measures. Despite the limited evidence, there is strong biological plausibility for the role of IVIg in IIM.

CONCLUSION

Robust, controlled evidence to support the use of IVIg using validated outcome measures is urgently required to guide therapeutic decision-making and maximize outcomes in IIM.

Developing international consensus on measures of improvement for patients with myositis

We discuss methods of developing consensus in measuring improvement in myositis. We consider selecting candidate variables, reliability and validity, percentage improvement /worsening rules, rules based on CART and logistic regression. We discuss criteria for determining an acceptable rule that include both numerical measures and physician acceptance.

Physical exercise as a treatment for adult and juvenile myositis

There is growing evidence to support the safety and efficacy of exercise in patients with adult and juvenile idiopathic inflammatory myopathies. Five randomized controlled trials including adult patients with polymyositis and dermatomyositis (DM) and additional open studies have demonstrated reduced impairment and activity limitation as well as improved quality of life. In addition, recent studies have shown reduced disease activity assessed by consensus disease activity measures and reduced expression of genes regulating inflammation and fibrosis. Furthermore, exercise could improve muscle aerobic capacity as shown by increased mitochondrial enzyme activity. These data suggest that intensive aerobic exercise and resistance training could reduce disease activity and inflammation and improve muscle metabolism. Encouraging results have been reported from available open studies including patients with inclusion body myositis (IBM) and juvenile DM, indicating reduced impairment, activity limitation and improved quality of life also in these patients. Larger studies are needed to increase understanding of the effects of exercise in patients with active, recent-onset polymyositis and DM as well as in patients with IBM and juvenile DM.

Rituximab in the Treatment of Jo1 Antibody–associated Antisynthetase Syndrome: Anti-Ro52 Positivity as a Marker for Severity and Treatment Response

Objective.

Rituximab (RTX) has been used successfully for the treatment of severe Jo1 antibody-associated antisynthetase syndrome. The aim of this retrospective study was to evaluate the effect of RTX in severe Jo1 antisynthetase syndrome and determine predictive factors for response.

Methods.

There were 61 patients with Jo1 antisynthetase syndrome identified; 18 of these received RTX. One patient was lost to followup. The remaining 17 patients and 30 out of 43 patients who were treated with conventional immunosuppressive (IS) drugs were followed for a mean of 35 months and 84 months, respectively.

Results.

Polymyositis/dermatomyositis (95%) and interstitial lung disease (ILD; 66%) were the dominant clinical manifestations. Detection of anti-Ro52 antibodies (43%) was significantly associated with acute-onset ILD (p = 0.016) with O2 dependency, and patients with high concentrations of anti-Ro52 (20%) had the highest risk (p = 0.0005). Sixteen out of 18 patients (89%) showed a fast and marked response to RTX. Among those patients who were highly positive for anti-Ro52, response to RTX was seen in 7 out of 7 cases (100%), but no response to cyclophosphamide (n = 4), cyclosporine A (n = 3), azathioprine (n = 9), methotrexate (n = 5), or leflunomide (n = 2) was observed. One patient treated with RTX died of pneumonia.

Conclusion.

RTX is effective in the treatment of severe forms of Jo1 antisynthetase syndrome. In our retrospective study, the presence of high anti-Ro52 antibody concentrations predicts severe acute-onset ILD and nonresponse to IS drugs. In contrast to conventional IS, RTX is equally effective in patients with Jo1 antisynthetase syndrome, independent of their anti-Ro52 antibody status.

Muscle myeloid type I interferon gene expression may predict therapeutic responses to rituximab in myositis patients

OBJECTIVE

To identify muscle gene expression patterns that predict rituximab responses and assess the effects of rituximab on muscle gene expression in PM and DM.

METHODS

In an attempt to understand the molecular mechanism of response and non-response to rituximab therapy, we performed Affymetrix gene expression array analyses on muscle biopsy specimens taken before and after rituximab therapy from eight PM and two DM patients in the Rituximab in Myositis study. We also analysed selected muscle-infiltrating cell phenotypes in these biopsies by immunohistochemical staining. Partek and Ingenuity pathway analyses assessed the gene pathways and networks.

RESULTS

Myeloid type I IFN signature genes were expressed at higher levels at baseline in the skeletal muscle of rituximab responders than in non-responders, whereas classic non-myeloid IFN signature genes were expressed at higher levels in non-responders at baseline. Also, rituximab responders have a greater reduction of the myeloid and non-myeloid type I IFN signatures than non-responders. The decrease in the type I IFN signature following administration of rituximab may be associated with the decreases in muscle-infiltrating CD19(+) B cells and CD68(+) macrophages in responders.

CONCLUSION

Our findings suggest that high levels of myeloid type I IFN gene expression in skeletal muscle predict responses to rituximab in PM/DM and that rituximab responders also have a greater decrease in the expression of these genes. These data add further evidence to recent studies defining the type I IFN signature as both a predictor of therapeutic responses and a biomarker of myositis disease activity.

Magnetic resonance measurement of muscle T2, fat-corrected T2 and fat fraction in the assessment of idiopathic inflammatory myopathies

OBJECTIVE

This study examines the utility of MRI, including T2 maps and T2 maps corrected for muscle fat content, in evaluating patients with idiopathic inflammatory myopathy.

METHODS

A total of 44 patients with idiopathic inflammatory myopathy, 18 of whom were evaluated after treatment with rituximab, underwent MRI of the thighs and detailed clinical assessment. T2, fat fraction (FF) and fat corrected T2 (fc-T2) maps were generated from standardized MRI scans, and compared with semi-quantitative scoring of short tau inversion recovery (STIR) and T1-weighted sequences, as well as various myositis disease metrics, including the Physician Global Activity, the modified Childhood Myositis Assessment Scale and the muscle domain of the Myositis Disease Activity Assessment Tool-muscle (MDAAT-muscle).

RESULTS

Mean T2 and mean fc-T2 correlated similarly with STIR scores (Spearman rs = 0.64 and 0.64, P < 0.01), while mean FF correlated with T1 damage scores (rs = 0.69, P < 0.001). Baseline T2, fc-T2 and STIR scores correlated significantly with the Physician Global Activity, modified Childhood Myositis Assessment Scale and MDAAT-muscle (rs range = 0.41-0.74, P < 0.01). The response of MRI measures to rituximab was variable, and did not significantly agree with a standardized clinical definition of improvement. Standardized response means for the MRI measures were similar.

CONCLUSION

Muscle T2, fc-T2 and FF measurements exhibit content validity with reference to semi-quantitative scoring of STIR and T1 MRI, and also exhibit construct validity with reference to several myositis activity and damage measures. T2 was as responsive as fc-T2 and STIR scoring, although progression of muscle damage was negligible during the study.

Current pharmacological treatment of idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies are uncommon and heterogeneous disorders. Their classification is based on distinct clinicopathologic features. Although idiopathic inflammatory myopathies share some similarities, different subtypes may have variable responses to therapy, so it is very important to distinguish the correct subtype. There are few randomised, double blind placebo controlled studies to support the current treatment. High dose corticosteroids continue to be the first-line therapy and other immunosupressive drugs are used in refractory cases, as well as steroid-sparing agents. Some novel therapeutic approaches have emerged as potential treatment including tacrolimus, intravenous immunoglobulin and rituximab, following good outcomes reported in case studies. However, more randomised controlled trials are needed. This review considers the current and the potential future therapies for inflammatory myopathies.

Proposal for a Candidate Core Set of Fitness and Strength Tests for Patients with Childhood or Adult Idiopathic Inflammatory Myopathies

OBJECTIVE

Currently there are no evidence-based recommendations regarding fitness and strength tests for patients with childhood or adult idiopathic inflammatory myopathies (IIM). This hinders clinicians and researchers in choosing the appropriate fitness- or muscle strength-related outcome measures for these patients. Through a Delphi survey, we aimed to identify a candidate core set of fitness and strength tests for children and adults with IIM.

METHODS

Fifteen experts participated in a Delphi survey that consisted of 5 stages to achieve a consensus. Using an extensive search of published literature and through the work of experts, a candidate core set based on expert opinion and clinimetrics properties was developed. Members of the International Myositis Assessment and Clinical Studies Group were invited to review this candidate core set during the final stage, which led to a final candidate core set.

RESULTS

A core set of fitness- and strength-related outcome measures was identified for children and adults with IIM. For both children and adults, different tests were identified and selected for maximal aerobic fitness, submaximal aerobic fitness, anaerobic fitness, muscle strength tests, and muscle function tests.

CONCLUSION

The core set of fitness- and strength-related outcome measures provided by this expert consensus process will assist practitioners and researchers in deciding which tests to use in patients with IIM. This will improve the uniformity of fitness and strength tests across studies, thereby facilitating the comparison of study results and therapeutic exercise program outcomes among patients with IIM.

Development of an internationally agreed minimal dataset for juvenile dermatomyositis (JDM) for clinical and research use

BACKGROUND

Juvenile dermatomyositis (JDM) is a rare autoimmune inflammatory disorder associated with significant morbidity and mortality. International collaboration is necessary to better understand the pathogenesis of the disease, response to treatment and long-term outcome. To aid international collaboration, it is essential to have a core set of data that all researchers and clinicians collect in a standardised way for clinical purposes and for research. This should include demographic details, diagnostic data and measures of disease activity, investigations and treatment. Variables in existing clinical registries have been compared to produce a provisional data set for JDM. We now aim to develop this into a consensus-approved minimum core dataset, tested in a wider setting, with the objective of achieving international agreement.

METHODS/DESIGN

A two-stage bespoke Delphi-process will engage the opinion of a large number of key stakeholders through Email distribution via established international paediatric rheumatology and myositis organisations. This, together with a formalised patient/parent participation process will help inform a consensus meeting of international experts that will utilise a nominal group technique (NGT). The resulting proposed minimal dataset will be tested for feasibility within existing database infrastructures. The developed minimal dataset will be sent to all internationally representative collaborators for final comment. The participants of the expert consensus group will be asked to draw together these comments, ratify and 'sign off' the final minimal dataset.

DISCUSSION

An internationally agreed minimal dataset has the potential to significantly enhance collaboration, allow effective communication between groups, provide a minimal standard of care and enable analysis of the largest possible number of JDM patients to provide a greater understanding of this disease. The final approved minimum core dataset could be rapidly incorporated into national and international collaborative efforts, including existing prospective databases, and be available for use in randomised controlled trials and for treatment/protocol comparisons in cohort studies.

Elevated Serum Levels of Soluble CD163 in Polymyositis and Dermatomyositis: Associated with Macrophage Infiltration in Muscle Tissue

Objective.

To investigate serum levels of soluble CD163 (sCD163) in patients with polymyositis (PM) and dermatomyositis (DM), and to correlate these to clinical manifestations and laboratory data.

Methods.

Serum levels of sCD163 were detected in 24 patients with PM, 84 patients with DM, and 46 healthy controls by using the ELISA method. Immunohistochemistry staining of macrophage infiltration in muscle tissue using anti-CD163 monoclonal antibody was conducted on muscle biopsy specimens from 13 patients with PM and 17 with DM.

Results.

Serum levels of sCD163 were significantly increased in patients compared with healthy controls (p < 0.001). Patients with interstitial lung disease (ILD) had statistically higher sCD163 levels than patients without ILD (p < 0.001). High serum sCD163 levels were associated with increased incidence of antinuclear antibody (p < 0.05), higher serum levels of immunoglobulin G (p < 0.01) and immunoglobulin A (p < 0.05), and increased erythrocyte sedimentation rates (p < 0.01). Serum sCD163 levels were inversely correlated with CD3+ T cell counts in peripheral blood of patients (r = −0.306, p < 0.01). Cross-sectional assessment and longitudinal study revealed a significant correlation between serum sCD163 levels and disease activity. Patients with high serum sCD163 levels showed a higher incidence of CD163+ macrophage infiltration in muscle tissue than patients with normal sCD163 levels (chi-square value = 10.804, p < 0.01).

Conclusion.

Serum levels of sCD163 were significantly elevated and correlated with disease severity in patients with PM/DM, suggesting serum sCD163 as a promising biomarker in the disease evaluation of PM/DM. Our finding of elevated serum sCD163 levels associated with muscle macrophage infiltration highlights the role activated macrophage plays in the pathogenesis of PM/DM.

Increased levels of HSPA5 in the serum of patients with inflammatory myopathies--preliminary findings

Endoplasmic reticulum (ER) stress is suggested to play an important role in the pathogenesis of myositis recently. The aim of this study was to investigate the serum concentration of an ER stress-specific chaperone protein HSPA5 in patients with inflammatory myopathies. Forty-five patients (27 with polymyositis (PM) and 18 with dermatomyositis (DM)) were included in the study, and all received prednisone therapy. Serum samples were collected from each patient before and after prednisone treatment. Serum HSPA5 levels were detected by enzyme-linked immunosorbent assays. The serum level of HSPA5 was significantly higher in myositis patients than in controls. In addition, the concentrations in the DM subgroup were significantly higher than in the PM groups. Serum HSPA5 levels were positively correlated with creatine kinase (CK) and C-reactive protein (CRP) in PM patients. In patients with DM, the serum HSPA5 concentrations were also found significantly correlated with CK, but not with CRP. After prednisone treatment, serum HSPA5 levels significantly decreased compared to baseline in steroid responders, but no marked decrease was observed in steroid non-responders. Serum HSPA5 is increased in patients with DM and PM. Increased concentrations of HSPA5 in serum may reflect the enhanced ER stress in muscle tissue. Decrease in serum HSPA5 levels appears in patients with clinical remission; therefore, HSPA5 may be a potential biomarker for inflammatory myopathies.

Myositis registries and biorepositories: powerful tools to advance clinical, epidemiologic and pathogenic research

PURPOSE OF REVIEW

Clinical registries and biorepositories have proven extremely useful in many studies of diseases, especially rare diseases. Given their rarity and diversity, the idiopathic inflammatory myopathies, or myositis syndromes, have benefited from individual researchers' collections of cohorts of patients. Major efforts are being made to establish large registries and biorepositories that will allow many additional studies to be performed that were not possible before. Here, we describe the registries developed by investigators and patient support groups that are currently available for collaborative research purposes.

RECENT FINDINGS

We have identified 46 myositis research registries, including many with biorepositories, which have been developed for a wide variety of purposes and have resulted in great advances in understanding the range of phenotypes, clinical presentations, risk factors, pathogenic mechanisms, outcome assessment, therapeutic responses, and prognoses. These are now available for collaborative use to undertake additional studies. Two myositis patient registries have been developed for research, and myositis patient support groups maintain demographic registries with large numbers of patients available to be contacted for potential research participation.

SUMMARY

Investigator-initiated myositis research registries and biorepositories have proven extremely useful in understanding many aspects of these rare and diverse autoimmune diseases. These registries and biorepositories, in addition to those developed by myositis patient support groups, deserve continued support to maintain the momentum in this field as they offer major opportunities to improve understanding of the pathogenesis and treatment of these diseases in cost-effective ways.

[Biologic therapy in idiopathic inflammatory myopathy]

The aim of this article is to study the evidence-based knowledge related to the use of biological therapies in patients diagnosed with idiopathic inflammatory myopathy (dermatomyositis, polymyositis and inclusion body myositis). In this review the leading published studies related to the use of biological therapy in patients with myositis are analysed; mainly those with high methodological standards, that means randomized and controlled studies. Methodological drawbacks due to the rarity and heterogeneity of these complex diseases are also addressed. Up to now is not possible to ascertain the biologics as a recommended therapy in patients with myositis, at least based in the current evidence-based knowledge, although it can not be neglected as a therapeutic option in some clinical situations, taking into account the scarce of effective treatments in those patients, especially in refractory myositis. Future studies probably will help to better define the role of biological therapies in patients with idiopathic inflammatory myopathy.

Developing a provisional, international minimal dataset for Juvenile Dermatomyositis: for use in clinical practice to inform research

BACKGROUND

Juvenile dermatomyositis (JDM) is a rare but severe autoimmune inflammatory myositis of childhood. International collaboration is essential in order to undertake clinical trials, understand the disease and improve long-term outcome. The aim of this study was to propose from existing collaborative initiatives a preliminary minimal dataset for JDM. This will form the basis of the future development of an international consensus-approved minimum core dataset to be used both in clinical care and inform research, allowing integration of data between centres.

METHODS

A working group of internationally-representative JDM experts was formed to develop a provisional minimal dataset. Clinical and laboratory variables contained within current national and international collaborative databases of patients with idiopathic inflammatory myopathies were scrutinised. Judgements were informed by published literature and a more detailed analysis of the Juvenile Dermatomyositis Cohort Biomarker Study and Repository, UK and Ireland.

RESULTS

A provisional minimal JDM dataset has been produced, with an associated glossary of definitions. The provisional minimal dataset will request information at time of patient diagnosis and during on-going prospective follow up. At time of patient diagnosis, information will be requested on patient demographics, diagnostic criteria and treatments given prior to diagnosis. During on-going prospective follow-up, variables will include the presence of active muscle or skin disease, major organ involvement or constitutional symptoms, investigations, treatment, physician global assessments and patient reported outcome measures.

CONCLUSIONS

An internationally agreed minimal dataset has the potential to significantly enhance collaboration, allow effective communication between groups, provide a minimal standard of care and enable analysis of the largest possible number of JDM patients to provide a greater understanding of this disease. This preliminary dataset can now be developed into a consensus-approved minimum core dataset and tested in a wider setting with the aim of achieving international agreement.

Predictors of clinical improvement in rituximab-treated refractory adult and juvenile dermatomyositis and adult polymyositis

OBJECTIVE

To identify the clinical and laboratory predictors of clinical improvement in a cohort of myositis patients treated with rituximab.

METHODS

We analyzed data for 195 patients with myositis (75 with adult polymyositis [PM], 72 with adult dermatomyositis [DM], and 48 with juvenile DM) in the Rituximab in Myositis trial. Clinical improvement was defined as 20% improvement in at least 3 of the following 6 core set measures of disease activity: physician's and patient's/parent's global assessment of disease activity, manual muscle testing, physical function, muscle enzymes, and extramuscular disease activity. We analyzed the association of the following baseline variables with improvement: myositis clinical subgroup, demographics, myositis damage, clinical and laboratory parameters, core set measures, rituximab treatment, and myositis autoantibodies (antisynthetase, anti-Mi-2, anti-signal recognition particle, anti-transcription intermediary factor 1γ [TIF-1γ], anti-MJ, other autoantibodies, and no autoantibodies). All measures were univariately assessed for association with improvement using time-to-event analyses. A multivariable time-dependent proportional hazards model was used to evaluate the association of individual predictive factors with improvement.

RESULTS

In the final multivariable model, the presence of an antisynthetase, primarily anti-Jo-1 (hazard ratio [HR] 3.08, P < 0.01), anti-Mi-2 (HR 2.5, P < 0.01), or other autoantibody (HR 1.4, P = 0.14) predicted a shorter time to improvement compared to the absence of autoantibodies. A lower physician's global assessment of damage (HR 2.32, P = 0.02) and juvenile DM (versus adult myositis) (HR 2.45, P = 0.01) also predicted improvement. Unlike autoantibody status, the predictive effect of physician's global assessment of damage and juvenile DM diminished by week 20. Rituximab treatment did not affect these associations.

CONCLUSION

Our findings indicate that the presence of antisynthetase and anti-Mi-2 autoantibodies, juvenile DM subset, and lower disease damage strongly predict clinical improvement in patients with refractory myositis.

Improvement in health and possible reduction in disease activity using endurance exercise in patients with established polymyositis and dermatomyositis: a multicenter randomized controlled trial with a 1-year open extension followup

OBJECTIVE

To determine the effects of a 12-week endurance exercise program on health, disability, VO2 max, and disease activity in a multicenter randomized controlled trial in patients with established polymyositis (PM) and dermatomyositis (DM), and to evaluate health and disability in a 1-year open extension study.

METHODS

Patients were randomized into a 12-week endurance exercise program group (EG; n = 11) or a control group (CG; n = 10). Assessments of health (Short Form 36 [SF-36]), muscle performance (5 voluntary repetition maximum [5 VRM]), activities of daily living (ADL), patient preference (McMaster Toronto Arthritis Patient Preference Disability Questionnaire), VO2 max, and disease activity (International Myositis Assessment and Clinical Studies criteria of improvement of the 6-item core set) were performed at 0 and 12 weeks. Disability assessments were performed again at 52 weeks in an open extension period. All assessments were performed by blinded observers.

RESULTS

The EG improved compared to the CG in SF-36 physical function and vitality (P = 0.010 and P = 0.046, respectively), ADL score (P = 0.035), 5 VRM (P = 0.026), and VO2 max (P = 0.010). More patients in the EG (7 of 11) were responders with reduced disease activity compared to none in the CG (P = 0.002). Correlations between VO2 max and SF-36 physical function were 0.90 and 0.91 at 0 and 12 weeks, respectively (P < 0.05). The EG improvement in 5 VRM was sustained up to 52 weeks compared to baseline (5.7 kg; P < 0.001), but not in ADL score or SF-36.

CONCLUSIONS

Endurance exercise improves health and may reduce disease activity in patients with established PM/DM. This potentially could be mediated through improved aerobic fitness. The results also indicate sustained muscle strength up to 1 year after a supervised program.

Developments in the classification and treatment of the juvenile idiopathic inflammatory myopathies

This review updates recent trends in the classification of the juvenile idiopathic inflammatory myopathies (JIIM) and the emerging standard of treatment of the most common form of JIIM, juvenile dermatomyositis. The JIIM are rare, heterogeneous autoimmune diseases that share chronic muscle inflammation and weakness. A growing spectrum of clinicopathologic groups and serologic phenotypes defined by the presence of myositis autoantibodies are now recognized, each with differing demographics, clinical manifestations, laboratory findings, and prognoses. Although daily oral corticosteroids remain the backbone of treatment, disease-modifying anti-rheumatic drugs are almost always used adjunctively and biologic therapies may benefit patients with recalcitrant disease.

[Therapeutic strategy in inflammatory myopathies (polymyositis, dermatomyositis, overlap myositis, and immune-mediated necrotizing myopathy)]

Inflammatory myopathies (IM) are a heterogeneous group of autoimmune muscle disorders of unknown origin that share clinical symptoms such as muscle weakness and histological features with the presence in muscle of inflammatory infiltrate. Based on clinical, histological and serological characteristics, IM can be divided into polymyositis, dermatomyositis, overlap myositis, cancer-associated myositis, immune-mediated necrotizing myopathy, and inclusion-body myositis. Because of their resistance to corticosteroids and immunosuppressive drugs, inclusion-body myositis will be treated separately in this issue. Major obstacles in conducting high quality randomized controlled trials in inflammatory myopathies include the low prevalence and the heterogeneity of these diseases as well as the lack of international consensus on the outcome measures. In the absence of adequate controlled therapeutic trials, treatment of these disorders remains largely empirical. Corticosteroids are the cornerstone therapy. Due to the chronic course of the disease, there is a frequent need to use additional immunosuppressive treatment both to improve the disease response and to reduce the side effects of corticosteroids. Intravenous immunoglobulin infusion is a costly treatment option that is reserved in the presence of refractory dermatomyositis based on a trial showing superior efficacy against control in patients with impaired swallowing or with contraindications to immunosuppressive drugs. In patients who fail second-line therapy, which usually consists of methotrexate plus corticosteroids, the diagnosis should be carefully reassessed before considering other treatment options including methotrexate plus azathioprine or biological agents such as rituximab.