The purpose of the study is to evaluate the efficacy and safety of Crovalimab versus Eculizumab in adult and adolescent participants With Paroxysmal Nocturnal Hemoglobinuria (PNH), a blood disorder that involves the breakdown of red blood cells, not previously treated with complement inhibitors. The study will enroll approximately 200 participants around the globe and will assign participants in different groups receiving Eculizumab or Crovalimab in a ratio of 2:1 (which means that for each participant receiving Crovalimab, two participants will receive Eculizumab)
Body weight >= 40 kg at screening. Willingness and ability to comply with all study visits and procedures. Documented diagnosis of PNH, confirmed by high sensitivity flow cytometry. LDH level >= 2x ULN at screening (as per local assessment). Vaccination against Neisseria meningitidis < 3 years prior to initiation of study treatment. Women of childbearing potential: agreement to remain abstinent or use contraception.
Current or previous treatment with a complement inhibitor. History of allogeneic bone marrow transplantation. History of Neisseria meningitidis infection within 6 months prior to screening and up to first study drug administration. Pregnant or breastfeeding, or intention of becoming pregnant during the study or within 6 months after the final dose of the study treatment. Participation in another interventional treatment study with an investigational agent or use of any experimental therapy within 28 days of screening or within 5 half-lives of that investigational product, whichever is greater. Concurrent disease, treatment, procedure or surgery, or abnormality in clinical laboratory tests that could interfere with the conduct of the study, may pose any additional risk for the participant, or would, in the opinion of the Investigator, preclude the participant's safe participation in and completion of the study. Splenectomy < 6 months before screening. Positive for Active Hepatitis B and C infection (HBV/HCV). History of or ongoing cryoglobulinemia at screening.