Rare Diseases Clinical Trials Update: Week 13, 2026

Published March 29, 2026 — 5 trials covered

By Victor Lafforgue, Founder of TrialsAlert. Blog posts are AI-drafted from ClinicalTrials.gov source data and reviewed by the editorial team. See our editorial policy for details.

A Study Evaluating the Efficacy, Safety, Pharmacokinetics and Pharmacodynamics of Crovalimab in Pediatric Participants With Atypical Hemolytic Uremic Syndrome (aHUS)

This Phase III study is exploring crovalimab as a new treatment option for children with atypical hemolytic uremic syndrome (aHUS), a rare disease that affects the blood and kidneys. If successful, crovalimab could help improve disease control and reduce complications, offering hope for better health outcomes in pediatric patients. The study is active but not recruiting, with results expected after all participants complete the trial.

A Study of Sepiapterin in Participants With Phenylketonuria (PKU)

This Phase 3b trial is testing the drug sepiapterin in children with phenylketonuria (PKU), a rare genetic disorder that can affect brain function. The study aims to find out if long-term treatment with sepiapterin can help preserve cognitive abilities in these children. Currently recruiting in several countries, this trial could lead to new options that support brain health for young patients with PKU.

Study to Evaluate Efficacy and Safety of Romosozumab Compared With Bisphosphonates in Children and Adolescents With Osteogenesis Imperfecta

This study is comparing romosozumab to standard bisphosphonate treatments in children and teens with osteogenesis imperfecta, a rare condition that causes fragile bones. The trial seeks to determine if romosozumab can strengthen bones and reduce the risk of fractures more effectively. Recruitment is ongoing worldwide, and the results may offer new ways to improve bone health and quality of life for young patients.

A Trial to Investigate Benralizumab in Children With Eosinophilic Diseases

This Phase 3 trial is testing benralizumab in children with eosinophilic diseases, including eosinophilic granulomatosis with polyangiitis (EGPA) and hypereosinophilia syndrome (HES). These are rare conditions marked by high levels of certain white blood cells that cause inflammation and tissue damage. The study aims to see if benralizumab can safely reduce symptoms and help manage these diseases. It is currently recruiting at multiple international sites.

To Investigate the Efficacy of Treatment With Oral NA-921 (Bionetide) Versus Placebo in Females With Rett Syndrome

This Phase 3 study is evaluating an oral medication called Bionetide for girls and women with Rett syndrome, a rare neurodevelopmental disorder. The trial hopes to determine whether Bionetide can improve symptoms and help with communication challenges faced by those with this condition. Recruiting in the United States and Australia, the study plans to enroll up to 210 participants, offering a potential new treatment avenue.

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