REGN3918 in Patients With Paroxysmal Nocturnal Hemoglobinuria (PNH) to Evaluate Its Long Term Safety, Efficacy and Tolerability.

An Open-label Extension Study to Evaluate the Long-term Safety, Tolerability, and Efficacy of REGN3918 in Patients With Paroxysmal Nocturnal Hemoglobinuria

The primary objective of the study is to evaluate the long-term safety, tolerability, and effect on intravascular hemolysis of REGN3918 in patients with paroxysmal nocturnal hemoglobinuria (PNH).

The secondary objectives of the study are:

• To evaluate the long-term effect of REGN3918 on intravascular hemolysis
• To assess the concentrations of total REGN3918 in serum
• To evaluate the occurrence of the immunogenicity of REGN3918

Key Inclusion Criteria:

• Patients with PNH who have completed, without discontinuation, study treatment in one of the parent studies in which they participated (either R3918-PNH-1852 [NCT03946748] or R3918-PNH-1853)

Key Exclusion Criteria:

• Significant protocol deviation(s) in the parent study based on the investigator's judgment and to the extent that these would (if continued) impact the study objectives and/or safety of the patient (for example, repetitive non-compliance with dosing by the patient)
• Any new condition or worsening of an existing condition which, in the opinion of the investigator, would make the patient unsuitable for enrollment or could interfere with the patient participating in or completing the study

NOTE: Other protocol defined exclusion criteria apply