The purpose of this clinical study is to evaluate the efficacy and safety of that test group was administered with Mycophenolate Mofetil in combination with corticosteroid in patients with advanced IgA nephropathy. The control group will be observed for up to 48 weeks without administration of Mycophenolate Mofetil.

The subject who signed the written agreement to participate in the clinical trial evaluates the conformity and then 1: 1 randomly allocated.

The study group were taken 48 weeks with MYREPT ® capsules in combination with corticosteroids and the control group were asked to preserve the conservative treatment regimen prior to the clinical trial registration Maintenance.

The subject who started taking the study medicine will carry out the examination and procedure if it has to be carried out for the visit via outpatient clinic at 4 weeks, 12 weeks, 24 weeks, 36 weeks, 48 weeks.

Inclusion Criteria

1. Patient aged 19 to 65 years old
2. Diagnosed with IgA nephropathy
3. Confirmed with Proteinuria more than 1.0 g / day at least twice within 6 months from the time of screening
4. If eGFR (by MDRD) is <50 mL / min / 1.73 m^2, ≥ 15 mL / min / 1.73 m^2
5. ACE inhibitor or ARB for at least 3 months
6. Willing and able to provide written informed consent.

Exclusion Criteria:

1. If eGFR (by MDRD) is <15 mL / min / 1.73 m^2
2. Blood pressure is SBP> 160 mmHg or DBP> 100 mmHg
3. Systemic infection or have been diagnosed with cancer within the last 5 years (excluding treatment squamous cell or basal cell carcinoma skin cancer)
4. serious digestive disorder
5. WBC <3000 / mm^3
6. Acute (within 4 weeks) or chronic(need to treatments) allergic/hypersensitivity reaction in the history of Investigational drugs
7. Administration of other Investigational drugs within 28days before screening period
8. Administration of Investigator drug or other immunosuppressants within 84days before screening period
9. Women in pregnant or breast-feeding or don't using adequate contraception.
10. Patient has conversation impairment because alcohol or drugs addiction history within 6months or mental illness, etc.
11. In investigator's judgment