Efficacy and Safety of the Combination of Pozelimab and Cemdisiran Versus Continued Eculizumab or Ravulizumab Treatment in Adult Patients With Paroxysmal Nocturnal Hemoglobinuria

Key Inclusion Criteria:

1. Diagnosis of PNH confirmed by a history of high-sensitivity flow cytometry fromprior testing

2. Treated with eculizumab or ravulizumab prior to screening visit as described in theprotocol Note: Biosimilars are not permitted, unless approved by the Sponsor

Key Exclusion Criteria:

1. Patients with a screening LDH >1.5 × ULN who have not taken their C5 inhibitorwithin the labeled dose interval at the dose prior to the screening LDH assessment

2. Receipt of an organ transplant, history of bone marrow transplantation or otherhematologic transplant

3. Body weight < 40 kilograms at screening visit

4. Any use of complement inhibitor therapy other than eculizumab or ravulizumab in the 26 weeks prior to the screening visit or planned use during the study with theexception of study treatments

5. Not meeting meningococcal vaccination requirements for eculizumab or ravulizumabaccording to the current local prescribing information (where available) and at aminimum documentation of meningococcal vaccination within 5 years prior to screeningvisit.

6. Any contraindication for receiving Neisseria meningitidis vaccination.

7. Positive for hepatitis B, and/ or hepatitis C as described in the protocol

8. History of cancer within the past 5 years, except for adequately treated basal cellskin cancer, squamous cell skin cancer, or in situ cervical cancer

9. Participation in another interventional clinical study (except R3918-PNH-2021) oruse of any experimental therapy within 30 days before screening visit or within 5half-lives of that investigational product, whichever is greater, with the exceptionof eculizumab or ravulizumab.

10. Patients with functional or anatomic asplenia

Note: Other protocol-defined Inclusion/ Exclusion Criteria apply