NCT03651505

Brief 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.

Trial Health

82
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
782

participants targeted

Target at P75+ for all trials

Timeline
80mo left

Started Jul 2018

Longer than P75 for all trials

Geographic Reach
6 countries

38 active sites

Status
active not recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress54%
Jul 2018Dec 2032

Study Start

First participant enrolled

July 16, 2018

Completed
1 month until next milestone

First Submitted

Initial submission to the registry

August 24, 2018

Completed
5 days until next milestone

First Posted

Study publicly available on registry

August 29, 2018

Completed
14.3 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 1, 2032

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 1, 2032

Last Updated

February 17, 2026

Status Verified

February 1, 2026

Enrollment Period

14.4 years

First QC Date

August 24, 2018

Last Update Submit

February 12, 2026

Conditions

Keywords

X-linked HypophosphatemiaFibroblast growth factor 23 (FGF23)KRN23XLHHypophosphatemiaFamilial Hypophosphatemic RicketsFGF23Crysvita

Outcome Measures

Primary Outcomes (3)

  • 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.

    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.

    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.

    10 years

Study Arms (2)

Prior Burosumab Clinical Trial Participants

Patients who participated in burosumab clinical trials and continue to receive burosumab via prescription from their physician.

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.

Other: No intervention

Interventions

Access to any treatment is through authorized commercial use and not as a part of this DMP

Not from Prior Burosumab Clinical TrialPrior Burosumab Clinical Trial Participants

Eligibility Criteria

Sexall
Healthy VolunteersNo
Age GroupsChild (0-17), Adult (18-64), Older Adult (65+)
Sampling MethodNon-Probability Sample
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.

You may qualify if:

  • 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.

You may not qualify if:

  • Concurrent enrollment in an Ultragenyx-sponsored clinical trial is NOT permitted.
  • Serious medical or psychiatric comorbidity.
  • Less than one year of life expectancy.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (38)

Children's Hospital of Alabama

Birmingham, Alabama, 35233, United States

Location

Children's Hospital Los Angeles

Los Angeles, California, 90027, United States

Location

Rady Children's Hospital San Diego

San Diego, California, 92123, United States

Location

University of California San Francisco

San Francisco, California, 94158, United States

Location

Children's Hospital of Colorado

Aurora, Colorado, 80045, United States

Location

Yale University School of Medicine

New Haven, Connecticut, 06520, United States

Location

Ann & Robert H. Lurie Children's Hospital of Chicago

Chicago, Illinois, 60611, United States

Location

Indiana University School of Medicine

Indianapolis, Indiana, 46202-5167, United States

Location

Johns Hopkins University

Baltimore, Maryland, 21218, United States

Location

Boston Children's Hospital

Boston, Massachusetts, 02115, United States

Location

Washington University School of Medicine

St Louis, Missouri, 63110, United States

Location

Duke University

Durham, North Carolina, 27708, United States

Location

Cincinnati Children's Hospital

Cincinnati, Ohio, 45229, United States

Location

Nationwide Children's Hospital

Columbus, Ohio, 43205, United States

Location

The Ohio State University Wexner Medical Center

Columbus, Ohio, 43205, United States

Location

Children's Hospital of Philadelphia

Philadelphia, Pennsylvania, 19104, United States

Location

Vanderbilt University - Department of Medicine

Nashville, Tennessee, 37212, United States

Location

Vanderbilt University - Department of Pediatrics

Nashville, Tennessee, 37232, United States

Location

Houston Methodist Research Institute

Houston, Texas, 77030, United States

Location

University of Texas, Health Science Center

Houston, Texas, 77030, United States

Location

University of Virgina School of Medicine

Charlottesville, Virginia, 22903, United States

Location

Children's Hospital of The King's Daughter

Norfolk, Virginia, 23507, United States

Location

Seattle Children's Hospital

Seattle, Washington, 98105, United States

Location

American Family Children's Hospital

Madison, Wisconsin, 53792, United States

Location

Hospital General de Niños Pedro de Elizalde

Buenos Aires, Buenos Aires F.D., C1270AAN, Argentina

Location

Hospital de Niños Dr. Ricardo Gutierrez

Buenos Aires, C1425EFD, Argentina

Location

Hospital Privado Universitario de Córdoba

Córdoba, Argentina

Location

Hospital Universitário Alcides Carneiro (HUAC)

São José, Campina Grande - PB, 58400-398, Brazil

Location

Instituto de Medicina Avancada (IMA Brasil)

São Paulo, São Paulo, 05437-000, Brazil

Location

CETI - Centro de Estudos em Terapias Inovadoras

Curitiba, 80030-110, Brazil

Location

Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo

São Paulo, 05403-000, Brazil

Location

British Columbia Children's Hospital

Vancouver, British Columbia, V6H 3N1, Canada

Location

Bone Research and Education Centre

Oakville, Ontario, ON L6M 1M1, Canada

Location

Shiner's Hospital for Children - Canada

Montreal, Quebec, H4A 0A9, Canada

Location

Children's Hospital Eastern Ontario Research Institute

Ottawa, K1H 5B2, Canada

Location

Pontificia Universidad Católica de Chile

Santiago, Santiago Metropolitan, Chile

Location

Hospital Universitario de San Vicente Fundación

Medellín, Antioquia, Colombia

Location

Hospital Infantil Universitario de San José

Bogotá, Cundinamarca, Colombia

Location

Related Publications (1)

  • 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.

Related Links

MeSH Terms

Conditions

Familial Hypophosphatemic RicketsRickets, HypophosphatemicHypophosphatemia

Condition Hierarchy (Ancestors)

RicketsBone Diseases, MetabolicBone DiseasesMusculoskeletal DiseasesHypophosphatemia, FamilialRenal Tubular Transport, Inborn ErrorsKidney DiseasesUrologic DiseasesFemale Urogenital DiseasesFemale Urogenital Diseases and Pregnancy ComplicationsUrogenital DiseasesMale Urogenital DiseasesMetal Metabolism, Inborn ErrorsMetabolism, Inborn ErrorsGenetic Diseases, InbornCongenital, Hereditary, and Neonatal Diseases and AbnormalitiesMetabolic DiseasesNutritional and Metabolic DiseasesCalcium Metabolism DisordersPhosphorus Metabolism DisordersVitamin D DeficiencyAvitaminosisDeficiency DiseasesMalnutritionNutrition Disorders

Study Officials

  • Ultragenyx Medical Director

    Ultragenyx Pharmaceuticals Inc.

    STUDY DIRECTOR

Study Design

Study Type
observational
Observational Model
COHORT
Time Perspective
PROSPECTIVE
Sponsor Type
INDUSTRY
Responsible Party
SPONSOR

Study Record Dates

First Submitted

August 24, 2018

First Posted

August 29, 2018

Study Start

July 16, 2018

Primary Completion (Estimated)

December 1, 2032

Study Completion (Estimated)

December 1, 2032

Last Updated

February 17, 2026

Record last verified: 2026-02

Locations