This study is to evaluate the efficacy and safety of a novel chemical synthetic agent iguratimod as treatment of refractory lupus nephritis. All subjects should have at least one failed immunosuppressive treatment and suffer active nephritis at the screening stage. The study period is 52 week. All the subject will receive therapy of iguratimod combined with steroids.

Inclusion Criteria:

• Active lupus nephritis:

Fulfill ACR classification criteria (2009) for SLE Proteinuria ≥1g/24h at screening stage experience at least one failed therapy within one year before screening, including but not limit to cyclophosphamide, methotrexate, azathioprine, mycophenolate mofetil, cyclosporin, tacrolimus and leflunomide. The regime can be monotherapy or combination. Any regime should be at least applied for six months.

• Body weight ≥40kg
• SLE-2K score ≥8
• Agreement of contraception
• Informed consent obtained

Exclusion Criteria:

• Active severe SLE-driven renal disease or unstable renal disease at screening
• Active severe or unstable neuropsychiatric SLE
• Clinically significant active infection including ongoing and chronic infections
• History of human immunodeficiency virus (HIV)
• Confirmed Positive tests for hepatitis B or positive test for hepatitis C
• Active tuberculosis
• Live or attenuated vaccine within 4 weeks prior to screening
• Subjects with significant hematologic abnormalities
• Abnormal liver function test at screening (ALT, AST or total bilirubin over 2 fold of upper normal level
• History of peptic ulcer or GI bleeding; treatment with warfarin or other anticoagulants within last 14 days