A Phase III Study Evaluating The Efficacy And Safety Of Crovalimab Versus Eculizumab In Participants With Paroxysmal Nocturnal Hemoglobinuria (PNH) Not Previously Treated With Complement Inhibitors.

Inclusion Criteria:

1. Body weight >= 40 kg at screening.
2. Willingness and ability to comply with all study visits and procedures.
3. Documented diagnosis of PNH, confirmed by high sensitivity flow cytometry.
4. LDH level >= 2x ULN at screening (as per local assessment).
5. Vaccination against Neisseria meningitidis serotypes A, C, W, < 3 years prior to initiation of study treatment; or, if not previously done, vaccination administered no later than one week after the first drug administration.
6. Women of childbearing potential: agreement to remain abstinent or use contraception during the treatment period and for 10.5 months after the final dose of crovalimab or for 3 months after the final dose of eculizumab (or longer if required by the local product label).

Exclusion Criteria:

1. Current or previous treatment with a complement inhibitor.
2. History of allogeneic bone marrow transplantation.
3. History of Neisseria meningitidis infection within 6 months prior to screening and up to first study drug administration.
4. History of myelodysplastic syndrome with Revised International Prognostic Scoring System (IPSS-R) prognostic risk categories of intermediate, high and very high.
5. Pregnant or breastfeeding, or intending to become pregnant during the study, within 10.5 months after the final dose of crovalimab, or 3 months after the final dose of eculizumab (or longer if required by the local product label).
6. 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.
7. 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.
8. Splenectomy < 6 months before screening.
9. Positive for Active Hepatitis B and C infection (HBV/HCV).
10. History of or ongoing cryoglobulinemia at screening.