Inclusion Criteria:

• For LNP023X2203, participants must have completed part 1 or part 2 of the trial. For LNP023A2301, participants must have completed the entire core trial defined as the full 24 month treatment period.

• eGFR* ≥ 20 ml/min/1.73m2

  *eGFR calculated using the CKD-EPI formula (or modified MDRD formula according to specific ethnic groups and local practice guidelines)

• Per investigator's clinical judgement, the participant may benefit from receiving the open-label treatment of iptacopan 200 mg b.i.d.

• Prior Vaccination against Neisseria meningitidis, Streptococcus pneumoniae and Haemophilus influenzae infections should be up to date (i.e. any boosters required administered according to local regulations.

• All participants must be on supportive care regimen of ACEi or ARB* as per KDIGO guidelines.

  • participants who are not taking KDIGO guideline doses because they have documented allergies or intolerance to ACEi and ARB are eligible for the study

Exclusion Criteria:

• participants who screen or baseline failed in the CLNP023X2203 Part 1 or Part 2, or CLNP023A2301 studies or who prematurely withdrew from either study for any reason.
• Evidence of severe urinary obstruction or difficulty in voiding; any urinary tract disorder other than IgAN at screening and before dosing with LNP023.
• Current (within 4 weeks of study drug administration in the REP) acute kidney injury (AKI)
• Presence of Rapidly Progressive Glomerulonephritis (RPGN) as defined by 50% decline in eGFR within the last 3 months.
• Participants treated with immunosuppressive or other immunmodulatory agents such as but not limited to cyclophosphamide, rituximab, infliximab, eculizumab, canakinumab, mycophenolate mofetil (MMF) or mycophenolate sodium (MPS), cyclosporine, tacrolimus, sirolimus, everolimus and/or systemic corticosteroids exposure (>7.5 mg/d prednisone/prednisolone equivalent) within 5 half-lives of respective medication or 90 days prior to first study drug administration, whichever is shorter. Rituximab requires 180 days wash out.
• Use of other investigational drugs at the time of enrolment, or within 5 half-lives of enrolment or within 30 days whichever is longer.
• History of recurrent invasive infections caused by encapsulated organisms, such as meningococcus and pneumococcus.