Rare Diseases Clinical Trials Update: Week 16, 2026

Published April 17, 2026 — 5 trials covered

By Victor Lafforgue, Founder of TrialsAlert

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 Phase 4 study is exploring the safety of pozelimab, an immunotherapy drug, in young children aged 1 to 5 with CHAPLE disease. CHAPLE is a rare condition that causes serious immune system problems and symptoms affecting the gut and heart. If pozelimab proves safe, it may become a new treatment option for managing this challenging disease and improving children's quality of life. The trial is currently recruiting participants in Turkey while closely monitoring safety and immune response.

A Study of NNZ-2591 in Pediatric Participants With Phelan-McDermid Syndrome

This Phase 3 clinical trial is testing NNZ-2591, an oral drug, in children affected by Phelan-McDermid Syndrome, a rare genetic disorder that impacts development and communication. The trial aims to see if the medication can help improve behavioral and communication skills in these children. Currently recruiting across the United States, the study plans to enroll 160 pediatric participants and could provide a much-needed treatment option where few exist today.

Nedosiran in Pediatric Patients From Birth to 11 Years of Age With PH and Relatively Intact Renal Function

This Phase 2 study has completed testing the drug nedosiran in children from birth up to 11 years who have primary hyperoxaluria, a rare kidney disease. The treatment aims to lower harmful oxalate levels in the body, which can damage the kidneys over time. Results from this international trial may offer hope for new ways to protect kidney function and reduce disease complications in young patients.

A Study of Intrathecal SHP611 in Children With Metachromatic Leukodystrophy

This Phase 2 trial involves an injection treatment called SHP611 for children with Metachromatic Leukodystrophy, a rare disease that causes progressive loss of movement and speech. The goal is to slow down the worsening of symptoms and give families more time with their children’s abilities. The study included about 36 children globally and has published results that could inform future care strategies.

Oxygen as an Acute Treatment in Alternating Hemiplegia of Childhood

This Phase 2 trial tested high-flow oxygen therapy to treat sudden motor attacks in children with Alternating Hemiplegia of Childhood, a rare neurological disorder. The treatment was given during disabling episodes to see if it could quickly reduce symptoms like paralysis and muscle stiffness. Completed in France with 24 participants, the study’s findings may lead to faster and more effective relief options for affected children.

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