Inflammatory myopathies: shedding light on promising agents and combination therapies in clinical trials

[Myositis: from diagnosis to treatment]

BACKGROUND

Inflammatory diseases of the skeletal muscle are important, often severe diseases with a considerable impact on the quality of life. In addition to muscle weakness there is often involvement of other organs, such as the heart, lungs and esophagus with symptoms such as dyspnea or dysphagia.

PURPOSE

A fast and effective treatment is only possible by an early and reliable diagnosis according to current national and international standards.

METHODS

The diagnostic repertoire includes autoantibody testing, imaging, muscle biopsy, detection of extramuscular manifestations, e.g., by high-resolution lung computed tomography (CT) and an individualized tumor search. An optimal treatment and the avoidance of irreversible damage, such as a loss of walking ability, are only possible through a good interdisciplinary cooperation including neurology or pediatrics, rheumatology, dermatology, neuropathology, pulmonology and cardiology.

RESULTS

In addition to standard immunosuppression with glucocorticosteroids, azathioprine or methotrexate, escalation treatment with rituximab is now well established. Interdisciplinary treatment according to national and international standards, such as guidelines on myositis, should be coordinated at qualified centers of excellence.

DISCUSSION

Helpful resources are the MYOSITIS NETZ ( www.myositis-netz.de ) and the International Myositis Society (iMyoS; www.imyos.org ).

An observational study of clinical recurrence in patients with interstitial lung disease related to the antisynthetase syndrome

OBJECTIVE

To describe the clinical characteristics and risk factors of clinical recurrence in interstitial lung disease related to antisynthetase syndrome (ARS-ILD).

METHODS

Patients diagnosed as ARS-ILD in Nanjing Drum Tower Hospital between January 2015 and November 2020 were retrospectively analyzed. Clinical information and treatment course were reviewed. The primary endpoint was the disease recurrence, and the secondary point was mortality. Univariate and multivariable Cox regression analyses were performed to identify risk factors for recurrence.

RESULTS

Totally, 132 patients with ARS-ILD received immunomodulation treatment from diagnosis. During follow-ups, sixty-nine patients showed recurrence, with a recurrency rate yielding 52.3%. The median duration from treatment initiation to recurrence was 11 (5-18) months. The median tapering course in the recurrence group was 8 (3-12.5) months, which was significantly shorter than the 16 (10-32) months in the no-recurrence group (p < 0.001). Fifty-eight patients experienced recurrence when the glucocorticoids (GC) dose dropped to 10 (9.375-15) mg/day. Twelve patients discontinued GC with a median treatment course of 11.5 (8-16.75) months, and 11 patients developed recurrence after discontinuing GC for 3 (1-4) months. Twelve patients died, with a mortality rate of 9.1%, and recurrence was not associated with increased mortality. The adjusted multivariate analysis showed that age, increased serum lactate dehydrogenase (LDH) level, relatively shorter tapering duration, and inappropriate GC discontinuation were associated with recurrence.

CONCLUSION

Recurrence of ARS-ILD was common during medication intensity reduction. Age, LDH, medication tapering duration, and discontinuation were risk factors for recurrence. Further efforts to reduce recurrence should take into consideration of these factors. Key Points • Recurrence is observed commonly with a recurrency rate 52.3% in patients with interstitial lung disease related to antisynthetase syndrome (ARS-ILD) when glucocorticoids (GC) tapering or discontinuation. • Age, increased serum lactate dehydrogenase (LDH) level, medication tapering duration, and GC discontinuation were identified to be significantly associated with the recurrence of ARS-ILD.

Antibody Therapies in Autoimmune Inflammatory Myopathies: Promising Treatment Options

Inflammatory myopathies, including polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM), necrotizing myopathy (NM), antisynthetase syndrome (ASS) and overlap myositis (OM), in short myositis, are rare diseases. All forms of myositis have progressive muscle weakness in common, with each subtype characterized by different autoantibody profiles, histological findings and extramuscular manifestations. Due to better understanding of the pathogenesis of the muscle inflammation in myositis, new molecular pathways for targeted therapy have been discovered. Current therapies aim at different components of the innate or the adaptive immune response. Additionally, non-inflammatory mechanisms in myositis have come into focus as possible treatment targets. The use of therapeutical antibodies in myositis has been examined in various clinical studies, several of them randomized controlled ones: Depletion of B-cells by rituximab has been established as treatment of refractory myositis. IVIG, an antibody therapy in the wider sense, has now been licensed for DM following a recent positive clinical trial. Negative study results were reported in randomized trials with infliximab, sifalimumab and bimagrumab. Studies on basiliximab and eculizumab are currently underway, and are expected to yield results in a couple of years. Despite some promising results of clinical studies with antibody therapy in myositis, further research is crucial to optimize the treatment for this debilitating disease and to find treatment alternatives for treatment-refractory patients.