Rituximab for the treatment of calcinosis in dermatomyositis: A case series and review of the literature
Subin Philip, Anna C Das, Aishwarya Gopal, Chengappa Kavadichanda, Muthuvatt Balaraman Adarsh, Sai Kumar Dunga, Mamatha Gorijavulu, Molly Mary Thabah, Vir Singh NegiAbstract
Objectives
Dystrophic calcinosis, a frequent complication of dermatomyositis (DM) and juvenile DM (JDM) is poorly responsive to treatment. We analysed the outcomes of calcinosis in patients with idiopathic inflammatory myositis (IIM) and calcinosis treated with rituximab.
Methods
IIM patients with calcinosis who received at least one cycle of rituximab (750 mg/m² in adults and 575 mg/m² in children on day 1 and day 14) were included. Baseline data included MMT8, patient global assessment, physician global assessment, myositis-specific and myositis-associated antibodies, duration, location and morphological pattern on plain radiographs of calcinosis. Improvement was defined as any reduction of calcinosis on plain radiographs.
Results
Of 224 IIM patients, 18 had calcinosis of whom 10 received rituximab (six JDM and four adult patients). Five of 10 patients were anti-NXP2, other MSAs were anti-MDA5, anti-PL7, and anti-Mi2. Seven of 10 patients had calcinosis at presentation; three developed subsequently. Predominant morphologies (radiographically) were nodular and sheet-like; two had mixed patterns. Eight of 10 patients also had active myositis (MITAX A or B) at rituximab initiation—of these, all showed either improvement or stabilization. Of the two with inactive disease treated solely for calcinosis, one stabilised; the other worsened. The one patient who worsened had diffuse distribution and mixed morphology of calcinosis.
Conclusion
In this small series, rituximab initiation during active myositis was associated with improvement or stabilization of calcinosis; however, given the limited sample size, this observation should be interpreted cautiously and requires prospective validation.