An Exploratory Study on the Efficacy and Safety of Abatacept in the Treatment of Refractory Dermatomyositis

Inclusion Criteria:

1. Dermatomyositis confirmed in accordance with Bohan-Peter criteria for inflammatorymyopathy, or clinically free myopathic dermatomyositis according to the revisedSontheimer criteria, aged 18 years or older, regardless of gender.
2. Patients with refractory dermatomyositis, specifically defined as those who havereceived glucocorticoid combined with at least one immunosuppressive therapy for atleast 3 months and have failed treatment or intolerance to treatment.Treatment failurewas defined as improvement of 3 core parameters in the core assessment measures ofiMACS <20%, or more than 2 parameters deterioration >25%.Treatment intolerance isdefined as a patient experiencing side effects that require discontinuation of thedrug or an underlying condition that prevents further use of the drug.Beforeenrollment, the dosage of glucocorticoids was <1mg/kg/day, prior use of at least oneimmunosuppressant (including methotrexate, azathioprine, cyclosporine, tacrolimus,mycophenolic ester and cyclophosphamide, etc.) at a stable dose >3 months.
3. If the patient has previously used biological agents, etc., the washout period shallbe completed.
4. Patients or their guardians fully understand the content of this study, are willing toparticipate in the study, and sign the informed consent.

Exclusion Criteria:

1. Other rheumatoid immune diseases: including but not limited to rheumatoid arthritis,systemic lupus erythematosus, systemic sclerosis, Sjogren's syndrome, primary biliarycirrhosis, etc.
2. combined with other myopathy causing myopathy and myasthenia;These includeneurological diseases (such as muscular dystrophy, myasthia gravis, amyotrophiclateral sclerosis, Guillain-Barre syndrome, etc.), tumors, drug effects (such asstatins, etc.), infections, genetic diseases, endocrine diseases, electrolytedisorders, rhabdomyolysis, etc.
3. Patients with severe heart, liver, kidney and other important organs and blood andendocrine system lesions:Including but not limited to decompensated cardiacinsufficiency, refractory hypertension and abnormal ecg, cereal third transaminase oraspertate aminotransferase more than 2 times higher than normal reference valueonline, renal tubular acidosis, renal interstitial lesions, renal insufficiency,serious leucopenia, severe anemia, severe thrombocytopenia and other serious diseases,such as tumor, etc.).
4. Active infection, glucocorticoid and immunosuppressive therapy may aggravateinfection;Hepatitis B virus surface antigen and hepatitis C antibody werepositive.Active TB patients who have been treated for active TB within the previous 3years, or who have been screened for latent TB, and who are positive for PPD combinedwith T-SPOT, or positive for sputum bacteria.
5. Pregnant and lactating women, women of reproductive age who cannot guaranteecontraception.
6. Patients with allergic constitution, who have been allergic to various drugs in thepast.
7. Mental disorders, or other patients unable to cooperate with treatment.