The primary objective of the study is to determine the effect of pozelimab on CD55-deficient protein-losing enteropathy (PLE; CHAPLE).

The secondary objectives of the study are:

• To evaluate the safety and tolerability of pozelimab in patients with CD55-deficient PLE disease
• To determine the effects of pozelimab on albumin and other serum proteins (total protein, immunoglobulins)
• To determine the effects of pozelimab on ascites
• To determine the effect of pozelimab on health-related quality of life
• To determine the effect of pozelimab on lab abnormalities observed in CD55-deficient PLE such as hypertriglyceridemia, thrombocytosis, and hypovitaminosis B12
• To describe the effects of pozelimab on the sparing of concomitant medications and reduction in hospitalization days
• To determine the effects of pozelimab on growth
• To characterize the concentration of pozelimab in patients with CD55-deficient PLE
• To assess the occurrence of ADA for pozelimab in patients with CD55-deficient PLE disease