Study of Ravulizumab in Proliferative Lupus Nephritis (LN) or Immunoglobulin A Nephropathy (IgAN)

Inclusion Criteria:

Common to both disease cohorts:

* Proteinuria ≥1 (gram \[g\]/day or g/g)
* Vaccinated against meningococcal infection
* Vaccinated for Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae according to national/local regulatory requirements

For LN cohort:

* Diagnosis of active focal or diffuse proliferative LN Class III or IV
* Clinically active LN, requiring/receiving immunosuppression induction treatment

For IgAN cohort:

* Diagnosis of primary IgAN
* Compliance with stable and optimal dose of renin-angiotensin system inhibitor treatment for ≥ 3 months

Exclusion Criteria:

Common to both disease cohorts:

* eGFR \< 30 milliliters/minute/1.73 meters squared
* Previously received a complement inhibitor (for example, eculizumab)
* Concomitant significant renal disease other than LN or IgAN
* History of other solid organ or bone marrow transplant
* Uncontrolled hypertension

For IgAN cohort:

* Diagnosis of rapid progressive glomerulonephritis
* Prednisone or prednisone equivalent \> 20 milligram (mg) per day for \> 14 consecutive days or any other immunosuppression within 6 months