The study is designed as a multicenter, single-arm, open label study to demonstrate the efficacy and safety of LNP023 (iptacopan) at a dose of 200 mg b.i.d. in adult patients with aHUS who are treatment naive to complement inhibitor therapy (including anti-C5 antibody). The study will enroll approximately 50 participants and assess the effects of iptacopan on a range of efficacy assessments relevant to aHUS including hematological and kidney parameters, dialysis requirement, changes in chronic kidney disease (CKD) stage, as well as patient reported outcomes (PRO) for fatigue and quality of life.