A Study Evaluating the Efficacy and Safety of ABP 959 Compared With Eculizumab in Adult Participants With PNH

Inclusion Criteria:

• Men and women ≥ 18 years of age.
• Historical diagnosis of PNH.
• Administration of eculizumab for ≥ 6 months and currently receiving 900 mg ofeculizumab.
• Hemoglobin ≥ 9.0 g/dL for at least 6 weeks before randomization.
• Lactate dehydrogenase < 1.5 × the upper limit of normal at screening.
• Platelet count ≥ 50 × 10^9/L.
• Absolute neutrophil count (ANC) ≥ 0.5 x 10^9/L (500/μL).
• Participants must be vaccinated against Neisseria meningitidis.
• Participants must sign an IRB/IEC-approved ICF before participation in any procedures.

Exclusion Criteria:

• Known or suspected hereditary complement deficiency.
• Clinically significant cardiovascular disease (including myocardial infarction,unstable angina, symptomatic congestive heart failure [New York Heart Association ≥Class III], serious uncontrolled cardiac arrhythmia), peripheral vascular disease,cerebrovascular accident, or transient ischemic attack in the previous 6 months.
• Evidence of acute thrombosis (liver Doppler ultrasound of hepatic and portal veins).
• Known to be positive for human immunodeficiency virus.
• Woman who is pregnant or breastfeeding.
• Participant is currently enrolled in or has not yet completed at least 30 days sinceending other investigational device or drug study(s), or participant is receivingother investigational agent(s).
• Participant has known sensitivity to any of the products to be administered during thestudy, including mammalian cell-derived drug products.
• History of meningococcal infection.
• Presence or suspicion of active bacterial infection, or recurrent bacterial infection.
• History of bone marrow transplantation.
• Red blood cell transfusion required within 12 weeks before randomization.
• Participant experienced ≥ 2 breakthrough events, (ie, signs and symptoms ofintravascular hemolysis, that require dose and/or schedule adjustments of eculizumab)in the previous 12 months before screening.