An Open-Label Efficacy and Safety Study of Pozelimab in Patients With CD55-Deficient Protein-Losing Enteropathy (CHAPLE Disease)

The primary objective of the study is to determine the effect of pozelimab on active 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 evaluate the effect of pozelimab on CD55-deficient PLE (both patients with active disease at baseline and those with inactive disease on eculizumab, switching to pozelimab)* 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 effects of pozelimab on stool consistency* 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 incidence of treatment-emergent ADA for pozelimab in patients with CD55-deficient PLE disease