Myositis Clinical Trials

• Fully understand the trial's purpose, nature, methodology, and potential adverse reactions, voluntarily participate as a subject, and sign the informed consent form.

• Aged 18-65 years (inclusive, based on the date of signing the informed consent form), regardless of gender.

• For Systemic Lupus Erythematosus (SLE):

‣ Diagnosed with SLE according to the 2019 EULAR/ACR classification criteria；

⁃ Meet at least one of the following: positive antinuclear antibody (ANA) and/or anti-dsDNA antibody and/or anti-Sm antibody at screening；

⁃ Had an inadequate response or relapse after standard therapy, defined as any of the following (alone or combined): glucocorticoids, antimalarials (hydroxychloroquine), immunosuppressants (including mycophenolate mofetil, cyclophosphamide, leflunomide, methotrexate, tacrolimus, cyclosporine, azathioprine), or biologics (rituximab, belimumab, telitacicept). Each regimen must have been administered for ≥3 months, and the subject must have received ≥2 immunosuppressants and/or biologics；

⁃ At screening, meet SLEDAI-2000 ≥7 and have at least one BILAG A or two BILAG B organ domain scores；

⁃ Prior to the first dose, subjects must have received glucocorticoids and/or antimalarials and/or immunosuppressants for ≥12 weeks, with stable doses for ≥30 days；

⁃ If receiving oral glucocorticoids (e.g., prednisone), the dose must be ≤40 mg/day at screening and during the screening period；

⁃ If using glucocorticoids alone, the dose must be ≥7.5 mg/day prednisone (or equivalent).

• For Idiopathic Inflammatory Myopathy (IIM):

‣ Diagnosed with possible or definite IIM per the 2017 EULAR/ACR classification criteria (≥5.5 points without biopsy; ≥6.7 points with biopsy) ；

⁃ Have at least one positive myositis-specific autoantibody (MSA) , myositis-associated autoantibody (MAA), or ANA at or prior to screening；

⁃ Had an inadequate response or relapse after conventional therapy, defined as glucocorticoids (prednisone \>1 mg/kg/day or equivalent) and ≥1 immunomodulatory drug (immunosuppressants: azathioprine, mycophenolate mofetil, cyclophosphamide, methotrexate, leflunomide, tacrolimus, cyclosporine; biologics: rituximab, belimumab; small molecules: tofacitinib), each for ≥3 months；

⁃ Have active IIM at screening, defined as meeting ≥3 of MMT-8 total score ≤141/150 with ≥20% strength loss in affected muscles; Physician global activity ≥2; Patient global activity ≥2; myositis disease activity assessment tool (MDAAT) ≥2; ≥2 muscle enzymes elevated, with one ≥1.5× upper limit of normal (ULN); health assessment questionnaire (HAQ) ≥0.25；

⁃ Prior to the first dose, subjects must have received glucocorticoids and/or immunosuppressants for ≥12 weeks, with stable glucocorticoid doses for ≥30 days and immunosuppressant doses for ≥60 days. Glucocorticoid dose must be ≤60 mg/day prednisone during screening；

⁃ If a subject is receiving oral glucocorticoids alone, the dose should be at least 7.5 mg/day of prednisone (or an equivalent dose of other glucocorticoids).

• For Systemic Sclerosis (SSc):

‣ Diagnosed with diffuse cutaneous SSc per the 2013 EULAR/ACR criteria ；

⁃ Have positive ANA and/or SSc-related antibodies；

⁃ Disease duration ≤5 years (from initial diagnosis)；

⁃ Had an inadequate response or relapse after conventional therapy. Conventional therapy is defined as treatment with glucocorticoids plus any of the following immunomodulatory agents: cyclophosphamide, mycophenolate mofetil, methotrexate, leflunomide, azathioprine, tacrolimus, cyclosporine, and/or biologics (such as rituximab and belimumab), with a cumulative treatment duration of \>6 months；

⁃ Modified Rodnan Skin Score (mRSS) ≥15 and ≤30 at screening with progression within 6 months；

⁃ Prior to the first dose, subjects must have received glucocorticoids and/or immunosuppressants for ≥12 weeks, with stable glucocorticoid doses for ≥30 days and immunosuppressant doses for ≥60 days. The glucocorticoid dose during the screening period should not exceed 10 mg/day of prednisone (or an equivalent dose of other glucocorticoids).

• Females of childbearing potential must use highly effective contraception from screening until 6 months after the last dose, refrain from oocyte donation, and ensure male partners use effective contraception.

• Males of childbearing potential must use effective contraception from screening until 6 months after the last dose, with no plans for fertility or sperm donation, and ensure female partners use effective contraception.