X-linked HypophosphatemiaNCT03651505
X-linked Hypophosphatemia Disease Monitoring Program
An observational study of X-linked Hypophosphatemia and Hypophosphatemic Rickets, run by Ultragenyx Pharmaceutical Inc at 38 sites in 6 countries.
Trial summary
The objectives of this observational study are to characterize XLH disease presentation and progression and to assess long-term effectiveness and safety of burosumab. Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- X-linked Hypophosphatemia, Hypophosphatemic Rickets
- How many people
- 782 participants
- Where
- 38 sitesin 6 countries
- Study dates
- 16 Jul 2018to Dec 2032
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Approximately 800 eligible adult and pediatric patients with XLH will be enrolled globally, with a minimum of 200 pediatric patients. Patients can enter the XLH-DMP regardless of how their XLH is being treated. Patients on Crysvita (burosumab) via prescription may begin taking Crysvita, per standard of care before or after enrolling in the XLH DMP.
Who may be able to join
- Willing and able to provide informed consent or, in the case of patients under the age of 18 years (or 16 years, depending on the region), provide assent (if required) and informed consent by a legally authorized representative after the nature of the study has been explained, and prior to any research-related procedures.
- Clinical diagnosis of XLH based on family history, OR confirmed PHEX mutation, OR biochemical profile consistent with XLH.
- Willing and able to comply with the study visit schedule and study procedures.
Who cannot join
- Concurrent enrollment in an Ultragenyx-sponsored clinical trial is NOT permitted.
- Serious medical or psychiatric comorbidity.
- Less than one year of life expectancy.
Trial locations and contacts
38 sites in 6 countries.
38 sites in 6 countries
United States24 sites
Children's Hospital of Colorado
Aurora, Colorado, 80045
Johns Hopkins University
Baltimore, Maryland, 21218
Children's Hospital of Alabama
Birmingham, Alabama, 35233
Boston Children's Hospital
Boston, Massachusetts, 02115
University of Virgina School of Medicine
Charlottesville, Virginia, 22903
Ann & Robert H. Lurie Children's Hospital of Chicago
Chicago, Illinois, 60611
Cincinnati Children's Hospital
Cincinnati, Ohio, 45229
Nationwide Children's Hospital
Columbus, Ohio, 43205
The Ohio State University Wexner Medical Center
Columbus, Ohio, 43205
Duke University
Durham, North Carolina, 27708
Houston Methodist Research Institute
Houston, Texas, 77030
University of Texas, Health Science Center
Houston, Texas, 77030
Indiana University School of Medicine
Indianapolis, Indiana, 46202-5167
Children's Hospital Los Angeles
Los Angeles, California, 90027
American Family Children's Hospital
Madison, Wisconsin, 53792
Vanderbilt University - Department of Medicine
Nashville, Tennessee, 37212
Vanderbilt University - Department of Pediatrics
Nashville, Tennessee, 37232
Yale University School of Medicine
New Haven, Connecticut, 06520
Children's Hospital of The King's Daughter
Norfolk, Virginia, 23507
Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, 19104
Rady Children's Hospital San Diego
San Diego, California, 92123
University of California San Francisco
San Francisco, California, 94158
Seattle Children's Hospital
Seattle, Washington, 98105
Washington University School of Medicine
St Louis, Missouri, 63110
Brazil4 sites
CETI - Centro de Estudos em Terapias Inovadoras
Curitiba, 80030-110
Hospital Universitário Alcides Carneiro (HUAC)
São José, Campina Grande - PB, 58400-398
Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo
São Paulo, São Paulo, 05403-000
Instituto de Medicina Avancada (IMA Brasil)
São Paulo, São Paulo, 05437-000
Canada4 sites
Shiner's Hospital for Children - Canada
Montreal, Quebec, H4A 0A9
Bone Research and Education Centre
Oakville, Ontario, ON L6M 1M1
Children's Hospital Eastern Ontario Research Institute
Ottawa, K1H 5B2
British Columbia Children's Hospital
Vancouver, British Columbia, V6H 3N1
Argentina3 sites
Hospital de Niños Dr. Ricardo Gutierrez
Buenos Aires, Buenos Aires, C1425EFD
Hospital General de Niños Pedro de Elizalde
Buenos Aires, Buenos Aires F.D., C1270AAN
Hospital Privado Universitario de Córdoba
Córdoba
Colombia2 sites
Hospital Infantil Universitario de San José
Bogotá, Cundinamarca
Hospital Universitario de San Vicente Fundación
Medellín, Antioquia
Chile1 site
Pontificia Universidad Católica de Chile
Santiago, Santiago Metropolitan
About this study
Official title: X-linked Hypophosphatemia Disease Monitoring Program (XLH-DMP)
The objectives of this observational study are to characterize XLH disease presentation and progression and to assess long-term effectiveness and safety of burosumab.
Read the detailed description
The XLH-DMP is a global, prospective, multicenter, longitudinal, long-term outcomes program for subjects on or off any treatment designed to characterize XLH disease presentation and progression, assess long-term safety and effectiveness of burosumab, as well as prospectively investigate longitudinal change over time across biomarker(s), clinical assessments, and patient/caregiver-reported outcome measures in a representative population. The XLH-DMP will collect demographic, biochemical, physiologic, disease severity, and progression data in patients taking burosumab and those not taking burosumab. In this DMP, patients will only have access to burosumab through authorized prescribed use. The Sponsor will not provide any treatments as part of the DMP.
- Being tested
- No intervention
- Keywords
- X-linked Hypophosphatemia, Fibroblast growth factor 23 (FGF23), KRN23, XLH, Hypophosphatemia, Familial Hypophosphatemic Rickets, FGF23, Crysvita
- Medical subject headings
- Familial Hypophosphatemic Rickets, Rickets, Hypophosphatemic, Hypophosphatemia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
No interventionOther
Access to any treatment is through authorized commercial use and not as a part of this DMP
| Study group | Role | What they receive |
|---|---|---|
| Prior Burosumab Clinical Trial Participants | Patients who participated in burosumab clinical trials and continue to receive burosumab via prescription from their physician. Receives: Other: No intervention | |
| Not from Prior Burosumab Clinical Trial | Patients may take other treatments for XLH and may start burosumab treatment at any time as prescribed by a physician. Receives: Other: No intervention |
What is being measured
The primary outcome is the main question the study is designed to answer.
Long-Term Safety of Burosumab
To assess the long-term safety of burosumab treatment in adult and pediatric patients with XLH, including overall renal health, the presence and/or progression of nephrocalcinosis and spinal stenosis, and pregnancy outcomes.
Measured: 10 years
Long-Term Effectiveness of Burosumab
To evaluate the long-term effectiveness of burosumab treatment on key manifestations of XLH, including skeletal health, stiffness, mobility and physical functioning.
Measured: 10 years
Clinical Course of XLH Disease
To illustrate the clinical, radiological, biochemical manifestations and progression of XLH over time in both untreated and treated patients with XLH.
Measured: 10 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Aug 2018
- Study start16 Jul 2018
- Primary completionDec 2032 (estimated)
- Study completionDec 2032 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (2)Papers the sponsor has linked to this study.
- Other trials for X-linked HypophosphatemiaStudies of the same condition, open and under way.
- More trials run by Ultragenyx Pharmaceutical IncThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 782 participants (actual)
Sponsor and investigators
- Lead sponsor
- Ultragenyx Pharmaceutical Inc
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Kyowa Kirin Co., Ltd.
- Responsible party
- Sponsor
- Investigators
- Ultragenyx Medical Director, Study director, Ultragenyx Pharmaceuticals Inc.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03651505
- Sponsor's protocol ID
- UX023-CL401
- Status last verified
- Aug 2026
- First submitted
- 24 Aug 2018
- Last updated
- 28 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Publications
Carpenter TO, Fukumoto S, Haffner D, Imel EA, Ozono K, Ishii H, Li Z, Sandilands K, Joos-Vandewalle P, Lee C, Kanematsu M, McCullough KP, Brandi ML. Advancing Patient Evidence in XLH (APEX): Baseline analysis of a global data unification program. Bone. 2025 Dec;201:117649. doi: 10.1016/j.bone.2025.117649. Epub 2025 Sep 15.
PubMed 40962182Portale AA, Ward L, Dahir K, Florenzano P, Ing SW, Jan de Beur SM, Martin RM, Meza-Martinez AI, Paloian N, Ashraf A, Dixon BP, Khan A, Langman C, Chen A, Wang C, Roberts MS, Tandon PK, Bedrosian C, Imel EA. Nephrocalcinosis and kidney function in children and adults with X-linked hypophosphatemia: baseline results from a large longitudinal study. J Bone Miner Res. 2024 Sep 26;39(10):1493-1502. doi: 10.1093/jbmr/zjae127.
PubMed 39151033
Study at a glance
From the registry record, last updated by the sponsor on 28 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- X-linked Hypophosphatemia Disease Monitoring Program (XLH-DMP)
- ClinicalTrials.gov ID
- NCT03651505
- Acronym / sponsor ID
- UX023-CL401
- Keywords
- X-linked Hypophosphatemia, Fibroblast growth factor 23 (FGF23), KRN23, XLH, Hypophosphatemia, Familial Hypophosphatemic Rickets, FGF23, Crysvita
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 782 participants (actual)
- Lead sponsor
- Ultragenyx Pharmaceutical IncIndustry (pharma, biotech, devices)
- Collaborators
- Kyowa Kirin Co., Ltd.
- Study start
- 16 Jul 2018 (actual)
- Primary completion
- Dec 2032 (estimated)
- Study completion
- Dec 2032 (estimated)
- First posted
- 29 Aug 2018 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The objectives of this observational study are to characterize XLH disease presentation and progression and to assess long-term effectiveness and safety of burosumab.
Detailed description
The XLH-DMP is a global, prospective, multicenter, longitudinal, long-term outcomes program for subjects on or off any treatment designed to characterize XLH disease presentation and progression, assess long-term safety and effectiveness of burosumab, as well as prospectively investigate longitudinal change over time across biomarker(s), clinical assessments, and patient/caregiver-reported outcome measures in a representative population. The XLH-DMP will collect demographic, biochemical, physiologic, disease severity, and progression data in patients taking burosumab and those not taking burosumab. In this DMP, patients will only have access to burosumab through authorized prescribed use. The Sponsor will not provide any treatments as part of the DMP.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Prior Burosumab Clinical Trial Participants | – | Other: No interventionPatients who participated in burosumab clinical trials and continue to receive burosumab via prescription from their physician. |
| Not from Prior Burosumab Clinical Trial | – | Other: No interventionPatients may take other treatments for XLH and may start burosumab treatment at any time as prescribed by a physician. |
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Approximately 800 eligible adult and pediatric patients with XLH will be enrolled globally, with a minimum of 200 pediatric patients. Patients can enter the XLH-DMP regardless of how their XLH is being treated. Patients on Crysvita (burosumab) via prescription may begin taking Crysvita, per standard of care before or after enrolling in the XLH DMP.
Key inclusion criteria (3 listed)
- Willing and able to provide informed consent or, in the case of patients under the age of 18 years (or 16 years, depending on the region), provide assent (if required) and informed consent by a legally authorized representative after the nature of the study has been explained, and prior to any research-related procedures.
- Clinical diagnosis of XLH based on family history, OR confirmed PHEX mutation, OR biochemical profile consistent with XLH.
- Willing and able to comply with the study visit schedule and study procedures.
Key exclusion criteria (3 listed)
- Concurrent enrollment in an Ultragenyx-sponsored clinical trial is NOT permitted.
- Serious medical or psychiatric comorbidity.
- Less than one year of life expectancy.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| No interventionAccess to any treatment is through authorized commercial use and not as a part of this DMP | Other | Not from Prior Burosumab Clinical Trial, Prior Burosumab Clinical Trial Participants |
Primary outcome
Long-Term Safety of Burosumab
Time frame: 10 years
To assess the long-term safety of burosumab treatment in adult and pediatric patients with XLH, including overall renal health, the presence and/or progression of nephrocalcinosis and spinal stenosis, and pregnancy outcomes.
Long-Term Effectiveness of Burosumab
Time frame: 10 years
To evaluate the long-term effectiveness of burosumab treatment on key manifestations of XLH, including skeletal health, stiffness, mobility and physical functioning.
Clinical Course of XLH Disease
Time frame: 10 years
To illustrate the clinical, radiological, biochemical manifestations and progression of XLH over time in both untreated and treated patients with XLH.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Aug 2026.
- Derived from this study: PubMed 40962182Carpenter TO, Fukumoto S, Haffner D, Imel EA, Ozono K, Ishii H, Li Z, Sandilands K, Joos-Vandewalle P, Lee C, Kanematsu M, McCullough KP, Brandi ML. Advancing Patient Evidence in XLH (APEX): Baseline analysis of a global data unification program. Bone. 2025 Dec;201:117649. doi: 10.1016/j.bone.2025.117649. Epub 2025 Sep 15.
- Derived from this study: PubMed 39151033Portale AA, Ward L, Dahir K, Florenzano P, Ing SW, Jan de Beur SM, Martin RM, Meza-Martinez AI, Paloian N, Ashraf A, Dixon BP, Khan A, Langman C, Chen A, Wang C, Roberts MS, Tandon PK, Bedrosian C, Imel EA. Nephrocalcinosis and kidney function in children and adults with X-linked hypophosphatemia: baseline results from a large longitudinal study. J Bone Miner Res. 2024 Sep 26;39(10):1493-1502. doi: 10.1093/jbmr/zjae127.
- Ultragenyx Transparency CommitmentLink provided by the sponsor.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Ultragenyx Medical Director study director
Ultragenyx Pharmaceuticals Inc.
38 sites in 6 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of X-linked Hypophosphatemia and Hypophosphatemic Rickets, run by Ultragenyx Pharmaceutical Inc at 38 sites in 6 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 28 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 38 sites in United States, Brazil, Canada, Argentina, Colombia and 1 more country. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Long-Term Safety of Burosumab (time frame: 10 years). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03651505, which also lists 2 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 28 Aug 2026.