A Randomized, Double-Blind, Placebo-Controlled Clinical Study on the Efficacy and Safety of Tocilizumab in the Treatment of Anti-MDA5 Antibody-Positive Adult Dermatomyositis
The 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
• All inclusion criteria must be met for eligibility:
‣ Age ≥ 18 years and \< 65 years; no gender restriction; total body weight ≥ 45 kg;
⁃ Diagnostic Criteria for Anti-MDA5-DM: Refer to the 2023 Chinese Expert Consensus on Diagnosis and Treatment of Anti-Melanoma Differentiation-Related Gene 5 Antibody-Positive Dermatomyositis in China. Dermatomyositis patients exhibiting one of the following manifestations-Gottron's papules, Gottron's rash, or erythema ab igne-along with positive serum anti-MDA5 antibodies, may be diagnosed with anti-MDA5-DM;
⁃ If patients have concomitant ILD, the following conditions must be met: i) Pulse oxygen saturation (SpO₂) ≥ 90% or PaO₂ ≥ 60 mmHg; ii) Pulmonary function tests showing forced vital capacity percentage of predicted (FVC%) ≥ 60% and carbon monoxide diffusion capacity percentage of predicted (DLco%) ≥ 40%; iii) High-resolution chest CT demonstrating pulmonary interstitial lesions involving \< 50% of lung fields;
⁃ Patients must have received oral prednisone (\< 1 mg/kg/day, or equivalent dose of other glucocorticoids) for ≥ 4 weeks prior to randomization;
⁃ Patients must have received a stable dose of a calcineurin inhibitor (CNI, such as cyclosporine or tacrolimus) for ≥4 weeks prior to randomization; if immunosuppressive therapy was discontinued prior to the screening visit, a washout period of at least 4 weeks is required;
⁃ Patients must receive prophylactic treatment with trimethoprim-sulfamethoxazole (TMP-SMZ, 400mg trimethoprim/80mg sulfamethoxazole) 1-2 tablets daily during treatment;
⁃ Women of childbearing potential must have a negative pregnancy test at study entry. If sexually active, they must agree to use effective contraception throughout the study period and must not intend to become pregnant during the study.
⁃ Patients voluntarily participate in this study and sign an informed consent form.