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

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

Key Inclusion Criteria:

• Clinical diagnosis of CD55-deficient PLE/CHAPLE disease (based on a history of PLE), confirmed by biallelic CD55 loss-of-function mutation detected by genotype analysis
• Active disease as defined by the protocol or inactive disease on eculizumab therapy (and whose treating physician has the expectation of future access to renewed eculizumab treatment should this be required), and is willing to discontinue eculizumab during screening and start pozelimab at baseline with no eculizumab wash-out

Key Exclusion Criteria:

• History of meningococcal infection
• No documented meningococcal vaccination within 3 years prior to screening and patient unwilling to undergo vaccination during the study
• No documented vaccination for Haemophilus influenzae and Streptococcus pneumoniae if applicable based on local practice or guidelines prior to screening and patient unwilling to undergo vaccination during the study if required per local practice or guidelines
• Presence of a concomitant disease that leads to hypoproteinemia at the time of starting pozelimab
• A concomitant disease that leads to secondary intestinal lymphangiectasia such as a fontan procedure for congenital heart disease

Note: Other protocol-defined Inclusion/Exclusion criteria apply.