A Study to Evaluate the Effect of Tacrolimus and Corticosteroid Combination Therapy in Patients With Minimal Change Nephrotic Syndrome

Inclusion Criteria: * patients who have been diagnosed with initial or relapsed primary minimal-change nephrotic syndrome * patients whose urine protein-creatinine ratio (UPCR) is more than 3.0 Exclusion Criteria: * patients whose eGFR is less than 30 ml/min/1.73 m2 * patients who were treated with immunosuppressants, such as tacrolimus, cyclosporine, cyclophosphamide (Cytoxan), mizoribine (Bredinin), levamisole, azathioprine, mycophenolate mofetil, or rituximab, within two weeks before the study * patients to whom more than 10 mg prednisolone or an equivalent dose of steroid was administered daily within two weeks before the study * patients who are pregnant, breastfeeding, or planning to be pregnant or to breastfeed within six months after the study completion, or who cannot or do not want to use any contraceptive method * patients who are hypersensitive to the investigational drug or to macrolide, such as azithromycin, clarithromycin, or roxithromycin * patients who were treated with a live vaccine within four weeks before the study * patients whose liver panel laboratory test result is three times the normal range, or acute hepatitis patients whose serum bilirubin has been clinically significantly higher than 3.6 mg/dL for more than 1 month * patients who have a significant general disease that makes it inappropriate for them to participate in this study as adjudged by the investigator (e.g., cardiovascular-acute myocardial infarction, heart failure \[classified as more than New York Heart Association {NYHA} class III\], hepatic/gastrointestinal/neurologic disease, blood disorder, cancer, infection, renal disorder other than minimal-change nephrotic syndrome, rheumatic arthritis with pneumonia interstitials) * patients who have genetic problems such as galactose intolerance, Lapp lactose deficiency, or glucose-galactose malabsorption * patients to whom another investigational drug was administered within 30 days from the enrollment in the study * patients who participated in the past phases of this study