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NCT Number: NCT07142343

A Study to Test the Safety of Pozelimab in Pediatric Participants 1 to 5 Years of Age With a Rare Disease Called CHAPLE (Complement Hyperactivation, Angiopathic Thrombosis, Protein-losing Enteropathy) Disease

This study is researching a drug called pozelimab (called "study drug"). The main aim of this study is to monitor the safety and tolerability of the study drug.

The study is focused on young children 1 to 5 years of age, who have CHAPLE disease. CHAPLE is a very rare hereditary disease that can cause potentially life-threatening symptoms related to the stomach and intestines (gastrointestinal symptoms), and symptoms related to the heart and blood vessels (cardiovascular symptoms).

The study is also looking at several other research questions, including:

* What side effects may happen from taking the study drug * How much study drug is in the blood at different times * Whether the study drug blocks Complement 5 (C5) in the body * Whether the study drug changes the level of a substance called CH50 measured in the blood * Whether the study drug changes the levels of albumin and other proteins * Whether the body makes antibodies against study drug, which could make the study drug less effective or could lead to side effects

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Key information

Conditions

CHAPLE Disease Digestive System Diseases Gastrointestinal Diseases Intestinal Diseases Protein-Losing Enteropathies

Age range

1 year–5 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Marmara University Hospital

Istanbul, 10 34899, Turkey (Türkiye)

Location status: Recruiting

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Key Inclusion Criteria:

  • Clinical diagnosis of CD55-deficient CHAPLE disease as described in the protocol
  • 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.
  • Parent(s)/legal guardian(s) are willing to provide written informed consent
  • Participant has active CHAPLE disease as described in the protocol

Key Exclusion Criteria:

  • History of meningococcal infection
  • 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
  • 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
  • Prior treatment with a complement inhibitor as described in the protocol
  • 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

Treatment and study plan

Pozelimab

Drug

Administered per the protocol

Other names: VEOPOZ

Primary outcomes

  1. Incidence of Treatment-Emergent Adverse Event (TEAEs)

    Time frame: Through week 52

  2. Severity of TEAEs

    Time frame: Through week 52

Secondary outcomes

  1. Concentrations of total pozelimab

    Time frame: Through week 52

  2. Concentrations of total C5 in serum

    Time frame: Through week 52

  3. Absolute change from baseline of albumin concentration in serum

    Time frame: Through week 52

  4. Percent change from baseline of albumin concentration in serum

    Time frame: Through week 52

  5. Absolute change from baseline of total protein

    Time frame: Through week 52

  6. Percent change from baseline of total protein

    Time frame: Through week 52

  7. Absolute change from baseline of total Immunoglobulin G (IgG)

    Time frame: Through week 52

  8. Percent change from baseline of total IgG

    Time frame: Through week 52

  9. Incidence of Anti-Drug Antibody (ADA) to pozelimab over time

    Time frame: Through week 52

  10. Titer of ADA to pozelimab over time

    Time frame: Through week 52

  11. Change from baseline of total complement activity CH50 over time

    Time frame: Through week 52

  12. Percent change from baseline of CH50 over time

    Time frame: Through week 52

Study contacts

Contact information is provided by the study sponsor or research team.

Clinical Trials Administrator

CONTACT

[email protected]

844-734-6643

Sponsors and collaborators

Lead sponsor

Regeneron Pharmaceuticals

Industry

Registry information

Official study title

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)

Important dates

Study start
2026
Primary completion
2030
Study completion
2030
First posted
Aug 26, 2025
Registry last updated
Apr 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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