Study of Ravulizumab in Pediatric Participants With Primary IgAN

Inclusion Criteria:

• Participant must be 2 to < 18 years of age at the time of signing the informedconsent or assent.

• Stable and maximum allowed or tolerated RASI (ACEI and/or ARB) dose for ≥ 3 monthsprior to Screening with no planned change during Screening through Week 106.

• UPCR ≥ 1.0 g/g from the mean of 3 first morning voids (FMV) collected within 1 weekduring the Screening Period

• Estimated GFR ≥ 30 mL/min/1.73 m2 during Screening

• Meningococcal infection vaccine

• Haemophilus influenzae type b and Streptococcus pneumoniae vaccine

• Participants who are receiving SGLT2i, DEARA (eg, sparsentan), MRA, ERA, or GLP-1agonists must be on a stable and maximum allowed or tolerated dose for ≥ 3 monthsprior to Screening with no planned change in dose through Week 34.

• Established diagnosis of primary IgAN diagnosis based on kidney biopsy within 3years prior to Screening or during the Screening Period

Exclusion Criteria:

• Diagnosis of rapidly progressive glomerulonephritis

• Secondary forms of IgAN not in the context of primary IgAN or IgAV

• Concomitant clinically significant renal disease other than IgAN or IgAVN

• Clinical remission of IgAN/IgAVN or clinically significant improvement inproteinuria within the last 6 months.

• Uncontrolled diabetes mellitus with HbA1c > 8.5%

• History of kidney transplant or planned kidney transplant during the PrimaryEvaluation Period.

• History of other solid organ (heart, lung, small bowel, pancreas, or liver) or bonemarrow transplant

• Splenectomy or functional asplenia

• Participants with nephrotic syndrome receiving albumin infusions or with acutekidney injury requiring dialysis within the last 6 months prior to Screening.

• Hemolytic uremic syndrome diagnosed any time prior to Screening.

• Planned urological surgery expected to influence kidney function within the studytime frame.

• Congenital immunodeficiency

• Active systemic bacterial, viral, or fungal infection within 14 days prior toenrollment

• Received biologics for the treatment of IgAN or IgAVN within≤ 6 months prior toScreening