Burosumab in Children and Adolescents With X-linked Hypophosphatemia

Study Overview
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Brief Summary
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In this prospective longitudinal cohort study we studied the efficacy and safety of burosumab in real-clinical practice for <13- and >13-years old children affected with X-linked hypophosphatemia. 57 children with XLH were switched from conventional treatment to burosumab. After 12 months we assessed the efficacy and safety of treatment with burosumab on the whole cohort and separately on the cohort of >13-years old adolescents.

Official Title
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12-months of Treatment With Burosumab in Children and Adolescents With X-linked Hypophosphatemia: a Prospective Longitudinal Cohort Study

Conditions
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Rare Diseases, X-linked Hypophosphatemia

Intervention / Treatment
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* Drug: Burosumab Injection


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: insufficient response or refractory to conventional therapy; complications of conventional therapy: hypercalciuria and/or nephrocalcinosis, and/or persistent secondary hyperparathyroidism; need for rapid restoration of phosphate metabolism, e.g., late diagnosis (aged >8 years) and/or preparation for planned orthopaedic surgery.

Ages Eligible for Study
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Minimum Age: 1 Year
Maximum Age: 20 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: The whole cohort<br>Children affected with X-linked hypophosphatemia of average age of 9.8 years were switch from conventional therapy to burosumab | Drug: Burosumab Injection<br>* Children affected with X-linked hypophosphatemia were switched from conventional therapy to burosumab<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Radiological changes in rachitic lesions evaluated with knee MRI | maximum width of the physis and transverse extent of widening | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| serum phosphate | mmol/l | 12 months | 
| renal phosphate reabsorption | mmol/l | 12 months | 
| alkaline phosphatase | U/l | 12 months | 
| 1,25(OH)vitaminD | pg/ml | 12 months | 
| parathyroid hormone | ng/l | 12 months | 
| height | standard deviation score | 12 months | 
| functional capacity | 6-minute walk test, standard deviation score | 12 months | 
| incidence of dental abcesses | dental examination | 12 months | 
| incidence of hearing problems | ORL examination, audiogramm | 12 months | 
| incidence of neurological problems (craniosynostosis, Chiari I malformation) | neurosurgical examination and brain MRI | 12 months | 
| incidence of nephrocalcinosis | renal ultrasound | 12 months | 
| incidence of hyperparathyroidism | blood levels of parathyroid hormone | 12 months | 
| incidence of any side effects | registration of any side effects during the treatment by telephone call | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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X-linked hypophosphataemia, fibroblast growth factor 23, burosumab, hyperparathyroidism