RecruitingBiological interventionRCT of Tocilizumab for Anti-MDA5+DMThe goal of this clinical trial is to learn if tocilizumab works to treat anti-MDA5+ dermatomyositis (anti-MDA5+DM) in adults. It will also learn about the safety of tocilizumab. The main questions it aims to answer are: Does tocilizumab improve patients' clinical symptoms? Does tocilizumab improve patients' respiratory failure? What medical problems do participants have when taking tocilizumab? Researchers will compare tocilizumab to a placebo (a look-alike substance that contains no drug) to see if tocilizumab works to treat patients with anti-MDA5+ DM. Participants will: Take tocilizumab or a placebo every two weeks for 2 months Visit the clinic once every 2 weeks for checkups and tests