A Study to Evaluate the Efficacy and Safety of Mizoribine in the Treatment of Refractory Nephrotic Syndrome

• Patients who have medical history with clear documentation of diagnosis of nephrotic syndrome
• Patient who received renal biopsy within 1 year prior to screening and confirmed the pathologic classification: Minimal Change Disease (MCD), IgA nephropathy, Mesangioproliferative Glomerulonephritis (MsPGN), Membranous Nephropathy (MN), Focal Segmental Glomerulosclerosis (FSGS)
• Patient with the above different pathologic classification who received adequate hormone therapy more than 8 weeks (including FSGS more than 12 weeks)prior to screening and have 24hr-urine protein≥2.0g/day at screening Adequate hormone dose is defined as prednisone (prednisolone) equivalent dose of 0.8 to 1.0 mg/kg/day (inclusive)
• Male or female patient between 18 and 70 years (inclusive) at informed consent obtained date
• Patient with body weight between 40kg and 80kg (inclusive) at screening
• Patients who sign the informed consent form

Exclusion Criteria:

• Other primary nephrotic syndrome, e.g. membrano-proliferative glomerulonephritis (MPGN)
• Secondary nephrotic syndrome (e.g. diabetic nephropathy, anaphylactic purpura nephritis, lupus nephritis, type B hepatitis-related nephritis, renal amyloidosis)
• Patient who had history of allergy to any investigational product (MZR, CTX) or hormone
• Patient who had received accumulated dosage of CTX >3g within one year prior to screening
• Patient who had received immunosuppressant or Chinese traditional medicine with immunosuppressive effect within 30 days prior to screening
• Patient who received other investigational drugs within 30 days prior to screening
• Patient who have received plasma exchange therapy or immunoadsorption therapy within 30 days prior to screening
• Patient who require pentostatin or live vaccine (not including flu vaccine)
• Patient who is undergoing renal replacement therapy
• Patient who received kidney transplantation
• Patient with malignancy
• Patient with severe hypertension (SBP > 160mmHg or DBP > 100mmHg) which has not been effectively controlled
• Patient with white blood cell count \<3×109/L /L(=3.0 GI/L)
• Patient with SCr > 176.8μmol/L
• Patient who has a value that is > 3 times of the upper limit of normal range for AST or ALT
• Patient with hepatitis B, hepatitis C or HIV infection
• Patient with other serious infections
• Patient who is unsuitable for participating in this study in the opinion of investigators ( e.g. uncontrolled diabetes, central nervous system lupus , lupus encephalopathy, active psychosis,osteonecrosis of the femoral head, fulminant hepatitis, peptic ulcer, etc.)
• Female patient who is pregnant, currently breast feeding or willing to become pregnant
• Patient with any other diseases that would affect the evaluation of efficacy or safety