Efficacy and Safety of Atacicept in IgA Nephropathy

Inclusion Criteria:

- Greater than or equal to (>=)18 years of age

- Biopsy-proven Immunoglobulin (IgA) nephropathy

- Urine Protein to Creatinine Ratio (UPCR) >= 0.75 and <= 6 milligram per milligram
(mg/mg) during screening

- Stable and optimal dose of Angiotensin converting enzyme (ACE) inhibitor and/or
angiotensin II receptor blockers (ARB) at least 8 weeks prior to screening

Exclusion Criteria:

- Concomitant significant renal disease other than IgA nephropathy

- IgA nephropathy with significant glomerulosclerosis or cortical scarring

- Diagnosis of Henoch-Schonlein purpura

- Failure to meet estimated glomerular filtration rate (eGFR) and biopsy requirement
criteria

- Serum IgG below 6 grams per liter (g/L)

- Use of cyclophosphamide ever or use of other immunosuppressants or systemic
corticosteroids within 4 months

- Active infection requiring hospitalization or treatment with parenteral
anti-infectives within 4 weeks

- History, or current diagnosis, of active tuberculosis (TB), or untreated latent TB
infection

- History of or positive HIV and/or positive for hepatitis B or Hepatitis C at screening

- History of malignancy

- Nursing or pregnancy

- Any condition, including any uncontrolled disease state other than IgA nephropathy