Clinical Trials

Inclusion Criteria:

* Documentation of IgAN diagnosis established on kidney biopsy obtained any time prior to or during the Screening Period for participants with eGFR ≥ 30 mL/min/1.73 m^2.
* For participants in the AdKD cohorts, eGFR 20 to 29 mL/min/1.73 m2 a kidney biopsy is required within 6 months prior to Screening or during the Screening Period.
* UPCR ≥ 0.75 g/g or UP ≥1 g/day calculated from the mean of two 24-hour urine during the Screening Period.
* Estimated GFR ≥ 30 mL/min/1.73 m2 at Screening.
* Stable and maximum allowed or tolerated RAASI (ACEI and/or ARB) dose for ≥ 3 months prior to Screening with no planned change during Screening through Week 106.
* Participants who are receiving SGLT2I, DEARA, MRA or ERA must be on a stable and maximum allowed or tolerated dose for ≥ 3 months prior to Screening with no planned change in dose through Week 106.

Exclusion Criteria:

* Diagnosis of rapid progressive glomerulonephritis as measured by eGFR loss ≥ 50% over a period of 3 months prior to Screening.
* Secondary IgAN (eg, due to systemic lupus erythematosus (SLE), cirrhosis, or celiac disease; IgAV-N may be eligible).
* Concomitant clinically significant renal disease other than IgAN.
* Prior use of immunosuppressive treatment within 3 months of screening.
* Uncontrolled diabetes mellitus with glycosylated hemoglobin (HbA1c) > 8.5%.
* Henoch-Schonlein purpura (IgAV) requiring systemic immunosuppressive therapy within 12 months of Screening.
* History of kidney transplant or planned kidney transplant during the Treatment Period.
* Splenectomy or functional asplenia.
* History of Neisseria meningitidis infection.
* Active systemic bacterial, viral, or fungal infection within 14 days prior to randomization.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 07/14/2026. Questions regarding updates should be directed to the study team contact.