NCT07287982

A Study to Assess the Safety, Tolerability, Efficacy, Pharmacokinetics, and Immunogenicity of Intravenous Administration of ARGX-119 in Pediatric Participants Aged 5 to Less Than 18 Years With Spinal Muscular Atrophy

A Phase 2 Double-Blinded, Randomized, Placebo-Controlled Study to Assess the Safety, Tolerability, Efficacy, Pharmacokinetics, and Immunogenicity of Intravenous Administration of ARGX-119 in Pediatric Participants Aged 5 to Less Than 18 Years With Spinal Muscular Atrophy

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 60 (estimated)
• Sponsor: argenx · Industry
• Sex: All
• Age: 5 Years – 17 Years
• Healthy volunteers: Not accepted

Summary

This study aims to find the correct dose of ARGX-119 for children with SMA. The study will also look at how safe the study drug is, how well it works, how it moves through the body, and how the immune system responds to it. The study consists of a double-blinded treatment period (DBTP) where participants will either receive ARGX-119 IV or placebo IV, in addition to disease-modifying therapy (DMT) for 24 weeks. Participants who complete the DBTP will enter the open-label active-treatment extension period (ATEP) during which all participants will receive ARGX-119 IV up to 100 weeks (approximately 2 years).

Detailed description

This phase 2 study aims to establish proof of concept with the age-appropriate dose of ARGX-119 in ambulant pediatric patients with spinal muscular atrophy (SMA). Despite available treatments, there remains an unmet medical need for patients with SMA. Neuromuscular junction (NMJ) dysfunction contributes to the pathophysiology of SMA, including muscle weakness and fatigability. Activation of muscle-specific kinase (MuSK) by ARGX-119 may stabilize and improve NMJ function in patients with SMA, reducing muscle weakness and fatigability, and improving quality of life.

Conditions

• Spinal Muscular Atrophy (SMA)

Interventions

Type	Name	Description
BIOLOGICAL	ARGX-119 IV	Intravenous infusion of ARGX-119
OTHER	Placebo IV	Intravenous infusion of placebo

Timeline

• Start date: 2025-12-19
• Primary completion: 2029-05-28
• Completion: 2029-05-28
• First posted: 2025-12-17
• Last updated: 2026-03-18

Locations

17 sites across 1 country: United States

Regulatory

• FDA-regulated drug study