A Study of Efgartigimod IV in Participants From 12 Years to Less Than 18 Years of Age With Chronic Immune Thrombocytopenia (ITP)

Official title

A Multicenter, Randomized, Double-blinded, Parallel-Arm, Placebo-Controlled, Pharmacokinetic and Pharmacodynamic Study Followed by an Open-Label Arm to Evaluate Efgartigimod IV in Pediatric Participants From 12 Years to Less Than 18 Years of Age With Chronic ITP

Overview

The main purpose of this study is to confirm the correct dose of efgartigimod IV for treating patients aged 12 to younger than 18 years with chronic immune thrombocytopenia (ITP). The study consists of a double-blinded treatment period (DBTP) in which the participants will be randomized in a 2:1 ratio to receive either efgartigimod IV or placebo IV. At the end of the treatment period (up to 24 weeks), all participants will receive efgartigimod IV during the first year open-label treatment period (OLTP1). At the end of the first OLTP1, participants may begin a second year (OLTP2). After the OLTP2, the participants will enter a follow-up period (approximately 8 weeks) while off study drug. The participants will be in the study for up to 138 weeks. More information can be found here: https://clinicaltrials.argenx.com/advancejunior

Interventions

• Biological Efgartigimod IV
  Intravenous infusion of efgartigimod
• Other Placebo IV
  Intravenous infusion of placebo

Primary outcome measures

• Efgartigimod serum concentrations in the DBTP [Time frame: Up to 24 weeks]
• Total IgG levels in the DBTP [Time frame: Up to 24 weeks]

Secondary outcome measures (11)

• Efgartigimod serum concentrations over time during the DBTP [Time frame: Up to 24 weeks]
• Percent change from baseline in total IgG levels in serum over time during the DBTP [Time frame: Up to 24 weeks]
• Incidence of AEs, SAEs and AEs leading to IMP discontinuation [Time frame: Up to 136 weeks]
• Sustained platelet count response between study weeks 19 and 24 of the DBTP and in OLTP1 for participants receiving placebo in the DBTP [Time frame: Up to 48 weeks]
• Extent of disease control during the DBTP and during the first 24 weeks of OLTP1 for those participants receiving placebo in the DBTP [Time frame: Up to 48 weeks]
• Changes from baseline for platelet counts over time [Time frame: Up to 76 weeks]
• Incidence of bleeding, assessed by the Modified Buchanan and Adix Bleeding Score for pediatric ITP [Time frame: Up to 76 weeks]
• Incidence of ADA and Nab against efgartigimod in serum [Time frame: Up to 76 weeks]
• Change from baseline in EQ-5D-5L [Time frame: Up to 76 weeks]
• Change from baseline in KIT Child Self-Report and KIT Parent Impact Report [Time frame: Up to 76 weeks]
• Change from baseline in peds FACIT-F [Time frame: Up to 76 weeks]

Eligibility criteria

Inclusion criteria

• Is aged 12 to less than 18 years when completing the informed consent process
• Has a documented duration of primary ITP of more than 12 months on the date the informed consent process is complete
• Has documented prior ITP treatment with at least 1 of the following treatments: corticosteroids, IVIg, anti-D immunoglobulin, thrombopoietin receptor agonist (TPO-RAs), or rituximab.
• Has documented prior response, defined as 1 platelet count of ≥50 × 10\^9/L to at least 1 of the following ITP treatments: prednisone, other or nonspecified corticosteroids, IVIg, or anti-D immunoglobulin
• Has documented insufficient response to a prior ITP treatment with corticosteroids, IVIg, anti-D immunoglobulin, TPO-RAs, rituximab, or splenectomy
• Has documented mean platelet count of less than 30 x10\^9/L

Exclusion criteria

• Secondary ITP according to the following definition by the International Working Group (IWG): all forms of immune-mediated thrombocytopenia except primary ITP
• Nonimmune thrombocytopenia
• ITP-associated critical or severe bleeding
• History of hereditary thrombocytopenia

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Quadruple blind

Primary purpose

Treatment

Study locations

Spain · 5 centers

• Hospital Universitari Vall d'Hebron — Barcelona
• Hospital Sant Joan de Deu Barcelona — Esplugues de Llobregat
• Hospital Infantil Universitario Nino Jesus (HIUNJS) — Madrid
• Hospital Materno-Infantil Universitario Gregorio Maranon — Madrid
• Hospital Universitario 12 de Octubre — Madrid

Italy · 4 centers

• Gaslini Children's Hospital — Genoa
• Fondazione IRCCS San Gerardo dei Tintori — Monza
• Bambino Gesu Children's Hospital — Roma
• A.O.U. Citta della Salute e della Scienza di Torino - Ospedale Infantile Regina Margherita — Torino

United Kingdom · 3 centers

• Cardiff and Vale NHS Trust - University Hospital of Wales (UHW) — Cardiff
• The Royal Hospital for Children - Glasgow Health Board — Glasgow
• Royal Manchester Children's Hospital - Manchester University NHS Foundation Trust — Manchester

Poland · 2 centers

• Samodzielny Publiczny Zaklad Opieki Zdrowotnej Uniwersytecki Szpital Kliniczny nr 4 — Lodz
• Uniwersytecki Szpital Dzieciecy w Lublinie — Lublin

Serbia · 2 centers

• Institute Of Mother And Child Healthcare Of Serbia Dr Vukan Cupic — Belgrade
• University Clinical Centre of Kragujevac — Kragujevac

France · 1 center

• Centre Hospitalier Universitaire de Bordeaux Groupe Hospitalier Pellegrin Hopital des Enfa — Bordeaux

Germany · 1 center

• Charite - Universitaetsmedizin Berlin - Campus Virchow-Klinikum (CVK) — Berlin

Lithuania · 1 center

• Vilnius University Hospital Santaros Klinikos, Children's Hospital — Vilnius

Romania · 1 center

• Institutul Clinic Fundeni — Bucharest

Identifiers

NCT: NCT07194850 · ARGX-113-2409 · 2025-521055-23-00

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗