Pozelimab safety in children 1 to 5 with CHAPLE disease

An Open-Label, Single-Arm Study Evaluating the Safety, Pharmacokinetics, Pharmacodynamics, and Immunogenicity of Pozelimab in Pediatric Patients 1 to 5 Years of Age With CD55-Deficient Protein-Losing Enteropathy (CHAPLE Disease)

This trial will test whether pozelimab is safe and tolerable in children ages 1 to 5 who have CHAPLE disease.

Quick facts

• Phase: Phase 4
• Study type: Interventional
• Enrollment: 5 (estimated)
• Ages: 1 Year to 5 Years
• Sex: All
• Sponsor: Regeneron Pharmaceuticals (Industry-sponsored)
• Drugs / interventions: pozelimab
• Locations: 1 site (Istanbul)
• Trial ID: NCT07142343 on ClinicalTrials.gov

What this trial studies

This phase 4 interventional study administers pozelimab to young children with genetically confirmed CD55-deficient CHAPLE disease to monitor safety and tolerability. Participants attend regular clinic visits for blood draws to measure drug levels, complement activity (C5 blockade and CH50), albumin and other protein levels, and anti-drug antibodies, while investigators record adverse events. Enrollment requires documented or protocol-administered meningococcal vaccination and, where applicable, Haemophilus influenzae and pneumococcal vaccination before dosing. The trial is sponsored by Regeneron and conducted at Marmara University Hospital in Istanbul.

Who should consider this trial

Good fit: Children aged 1–5 with clinically and genetically confirmed CD55-deficient CHAPLE disease who have active disease and whose guardians can comply with clinic visits and required vaccinations are ideal candidates.

Not a fit: Patients without CD55-deficient CHAPLE disease, those with a history of meningococcal infection, or those unwilling/unable to receive required vaccinations are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, pozelimab could reduce life-threatening gastrointestinal and vascular complications in young children by controlling complement overactivation.

How similar studies have performed: Other anti-C5 therapies such as eculizumab have shown benefit in CHAPLE and related complement disorders, though published pediatric data for pozelimab specifically are limited.

Eligibility criteria

Key Inclusion Criteria:

1. Clinical diagnosis of CD55-deficient CHAPLE disease as described in the protocol
2. Parent(s)/legal guardian(s) are willing and able to comply with participant's clinic visits and study-related procedures, including participant's completion of the full series of meningococcal vaccinations required per protocol.
3. Parent(s)/legal guardian(s) are willing to provide written informed consent
4. Participant has active CHAPLE disease as described in the protocol

Key Exclusion Criteria:

1. History of meningococcal infection
2. No documented meningococcal quadrivalent (serotype ACWY) vaccination prior to screening and participant's parent(s)/legal guardian(s) are unwilling for participant to undergo vaccination during the study as described in the protocol
3. No documented vaccination for Haemophilus influenzae and Streptococcus pneumoniae if applicable based on local practice or guidelines prior to screening as described in the protocol
4. Prior treatment with a complement inhibitor as described in the protocol
5. Presence of a concomitant disease that leads to hypoproteinemia or secondary intestinal lymphangiectasia as described in the protocol

Note: Other Protocol Defined Inclusion/ Exclusion Criteria Apply

Where this trial is running

Istanbul

• Marmara University Hospital — Istanbul, Turkey (Türkiye) (Recruiting)

Study contacts

• Study coordinator: Clinical Trials Administrator

Conditions CHAPLE Disease; CD55-deficient PLE; CD55 loss-of-function mutation; Complement hyperactivation; Angiopathic thrombosis; Protein-losing enteropathy; Total Complement Hemolytic Activity Assay