This is a multicenter, single arm, open-label, extension study to evaluate the long-term safety, tolerability, and efficacy of iptacopan in participants with aHUS.

The extension study Baseline/Day 1 visit is equivalent to the End of Treatment visit of the parent study. The study will begin on Day 1 followed by on-site visits every 4 months during the study treatment period. A Safety Follow Up tele-visit must be conducted 7 days after last study treatment to collect information on Adverse Events.

Inclusion Criteria:

1. Signed informed consent must be obtained prior to participation in the open label extension study
2. Willing and able to comply with the study Schedule of Activities
3. Participants who have completed the full study treatment period of any prior "Novartis sponsored" iptacopan Phase 3 clinical trial in aHUS (e.g. CLNP023F12301 , CLNP023F12302), are still on iptacopan study treatment and derive benefit from it as per Investigator's judgement
4. Prior vaccinations against Neisseria meningitidis, Streptococcus pneumoniae and Haemophilus influenzae infections should be up to date (i.e., any boosters required should be administered according to local guidelines)

Exclusion Criteria:

1. Concomitant treatment with any complement inhibitor as well as concomitant treatment with any of the prohibited drugs
2. Any comorbidity or medical condition (including but not limited to any active systemic bacterial, viral or fungal infection or malignancy) that, in the opinion of the Investigator could put the participant at risk
3. Active infection or history of recurrent invasive infections caused by encapsulated bacteria such as Neisseria meningitidis, Streptococcus pneumoniae or Haemophilus influenzae
4. History of hypersensitivity to iptacopan or its excipients or to drugs of similar chemical classes
5. Pregnant or nursing (lactating) women
6. Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, unless they are using effective methods of contraception during dosing of investigational drug and for 1 week after stopping of investigational drug.

Other protocol-defined inclusion/exclusion criteria may apply.

Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations.

This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com