Idiopathic inflammatory myopathies (IIM), which include
dermatomyositis (DM) and
polymyositis (PM), are chronic systemic diseases associated with high morbidity and functional disability. Current treatment is based on the use of
glucocorticoids and immunosuppressive drugs, but a considerable number of patients is refractory to traditional
therapy. That has led to the attempted use of biologics based on the physiopathogenesis of IIM. From the immunopathological viewpoint, PM and DM differ: the former is more related to cellular immunity, while the latter, to humoral immunity. In both, however, elevated concentrations of proinflammatory
interleukins (TNF, IL-1, IL-6) and increased expression of molecules related to costimulation of T lymphocytes have been described; thus, the use of biologics in those conditions seems reasonable. Considering the biologics available, open-label studies are scarce, comprising mainly case reports and series.
TNF blockers have yielded conflicting results, with no evidence of good response to treatment. The anti-CD20
therapy has the most promising results. Data on T lymphocyte costimulation blockade and anti-IL-6
therapy are extremely scarce, preventing any consideration. Thus, the use of biologics in IIM still remains an unconquered frontier. Biologics may have an important role in the management of IIM refractory to conventional
therapy, but further prospective studies based on objective parameters of response to treatment are needed. So far, anti-CD20
therapy seems to be the most promising treatment for refractory IIM.