Calcinosis remains one of the most difficult complications to manage in patients with dermatomyositis (DM) and juvenile dermatomyositis (JDM), often causing pain, disability, and reduced quality of life. New findings published in Rheumatology suggest that rituximab may offer benefits for some patients, particularly when treatment is initiated during periods of active muscle disease.
Study Overview
As reported in the Oxford Academic, researchers evaluated outcomes in patients with idiopathic inflammatory myopathies (IIM) complicated by calcinosis who were treated with rituximab. The analysis focused on changes in calcified deposits seen on imaging after at least one course of therapy.
Among 224 patients with IIM identified at a single center, 18 had calcinosis. Of those, 10 patients received rituximab and were included in the study. The cohort consisted of six individuals with JDM and four adults with dermatomyositis.
Investigators collected clinical data including muscle strength assessments, physician and patient evaluations, autoantibody profiles, and radiographic characteristics of calcinosis. Any reduction in calcific deposits on follow-up radiographs was considered an improvement.
Patient Characteristics
Half of the treated patients tested positive for anti-NXP2 antibodies, which are frequently associated with calcinosis in inflammatory myopathies. Other myositis-specific antibodies identified in the cohort included anti-MDA5, anti-PL7, and anti-Mi2.
Seven patients had calcinosis at the time of their initial disease presentation, while three developed the complication later in their disease course. Imaging most commonly demonstrated nodular or sheet-like calcific deposits, although two patients exhibited a combination of calcinosis patterns.
Key Findings
Eight of the 10 patients had ongoing active myositis when rituximab therapy began. In this group, all experienced either improvement or stabilization of calcinosis during follow-up.
The remaining two patients received rituximab despite having inactive muscle disease, with calcinosis serving as the primary treatment target. One of these individuals showed stable disease, while the other experienced progression of calcific deposits.
Notably, the patient whose calcinosis worsened had particularly extensive disease, characterized by widespread distribution and mixed radiographic morphology.
Clinical Implications
The findings suggest that rituximab may be most useful when administered in the setting of active inflammatory disease rather than as a treatment for established calcinosis alone. Control of ongoing muscle inflammation may play an important role in limiting further calcification or promoting gradual improvement.
However, the authors emphasized that conclusions should be interpreted carefully because of the study’s small sample size and retrospective design. Larger prospective studies are needed to determine which patients are most likely to benefit and to clarify the drug’s role in managing calcinosis associated with DM and JDM.
Bottom Line
In this small case series, rituximab was associated with stabilization or improvement of calcinosis in most patients with dermatomyositis or juvenile dermatomyositis, particularly when active myositis was present at the time treatment was started. While the results are encouraging, more robust clinical evidence is required before rituximab can be considered an established therapy for calcinosis in these populations.
