Finding the right burosumab dose for children with XLH
A Retrospective Observational Study of the Effect of Dosing Regimen of Burosumab on Biochemical Control of Serum Phosphate Levels in Patients With X-linked Hypophosphataemia (XLH)
This project tests whether children with X-linked hypophosphataemia can achieve good phosphate control on starting burosumab doses below 0.8 mg/kg.
Quick facts
| Study type | Observational |
|---|---|
| Enrollment | 120 (estimated) |
| Ages | 2 Years to 18 Years |
| Sex | All |
| Sponsor | University of Nottingham Academic / other |
| Drugs / interventions | Burosumab |
| Locations | 1 site (Nottingham) |
| Trial ID | NCT07183579 on ClinicalTrials.gov |
What this trial studies
This is a multi-centre, pragmatic retrospective observational review of paediatric metabolic bone centre records in England. The study will include children with genetically confirmed PHEX-related XLH who received at least 12 months of continuous burosumab under paediatric dosing criteria. Investigators will describe dosing variation across centres and compare biochemical control, growth and rickets-related outcomes for patients started on lower versus standard dosages. The goal is to determine how often lower starting doses maintain target phosphate levels and to inform real-world dosing practice.
Who should consider this trial
Good fit: Ideal candidates are paediatric patients with genetically confirmed XLH who began burosumab under paediatric criteria and have at least 12 months of continuous treatment before their 18th birthday.
Not a fit: Adults managed under adult dosing criteria, patients without genetic confirmation of XLH, very young children below paediatric initiation age, or those with severe disease requiring higher doses are unlikely to benefit from lower-dose recommendations.
Why it matters
Potential benefit: If successful, the results could support using lower burosumab starting doses for some children, reducing drug exposure, injection burden, and treatment costs while keeping phosphate under control.
How similar studies have performed: Randomised and open-label trials have shown burosumab normalises phosphate and improves rickets at recommended doses, but real-world evidence on routine success with lower starting doses is limited.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * A diagnosis of x-linked hypophosphataemia (XLH) including genetic confirmation of a PHEX mutation. * Has received at least 12 months of continuous Burosumab treatment under paediatric criteria (given Burosumab is not started till a child is 12 months old in England, the minimum age will, therefore, be 2 years old) prior to their 18th birthday. Exclusion Criteria: * Burosumab received under adult criteria (patients who have received both Burosumab under paediatric arrangements and, subsequently, adult arrangements, can have data obtained during paediatric dosing included).
Where this trial is running
Nottingham
- Nottingham University Hospitals NHS Trust — Nottingham, United Kingdom (Recruiting)
Study contacts
- Principal investigator: James Law, BMBS, PhD, MRCPCH — University of Nottingham
- Study coordinator: James M Law, BMBS, PhD, MRCPCH
- Email: james.law@nottingham.ac.uk
- Phone: 01159249924
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.