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Burosumab and 1-25 (OH) Vitamin D on Human Osteoclasts (HYPO-CLASTE)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT04184661
Recruitment Status : Recruiting
First Posted : December 3, 2019
Last Update Posted : January 22, 2021
Information provided by (Responsible Party):
Hospices Civils de Lyon

Brief Summary:

Fibroblast growth factor 23 (FGF23) is the cornerstone of phosphate / calcium / vitamin D metabolism: it is synthesized mainly by osteocytes and acts as a Phosphating agent, inhibitor of dihydroxyvitamin D, and inhibitor of synthesis and secretion of Parathyroid hormone (PTH) in most tissues.

The specific role of FGF23 on bone has yet to be demonstrated. In some diseases such as hypophosphatemic rickets (HR), the direct role of FGF23 on bone has not yet been studied to our knowledge, whereas these genetic hypophosphatemias are secondary to overexpression of FGF23, whether an activating mutation of FGF23 or inhibitory mutations of its inhibitors (Dentin matrix acidic phosphoprotein 1 (DMP1) and Phosphate-regulating neutral endopeptidase, X-linked (PHEX)). However, patients with X-linked hypophosphatemic rickets (XLH) have higher circulating FGF23 levels than healthy controls and these levels are higher in treated patients.

Management of XLH consists primarily of correcting the native vitamin D defect by prescribing active vitamin D analogs as well as phosphate supplementation to improve bone mineralization and decrease dental complications, growth, and bone deformities. Recently, a new therapeutic option has been developed for XLH, burosumab, a human monoclonal antibody that binds and inhibits FGF23 activity. The use of burosumab is currently authorized in France in some pediatric patients with severe forms of XLH.

Independently of the indirect bone effects of phosphate correction and vitamin D levels, the direct role of burosumab on bone cells has never been studied. The objective of this project is to study the osteoclastic biology of patients with HR compared to control patients, and to evaluate the direct impact of the treatments used in this pathology on human osteoclasts.

Condition or disease Intervention/treatment
Hypophosphatemic Rickets Other: blood sample

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Study Type : Observational
Estimated Enrollment : 15 participants
Observational Model: Case-Control
Time Perspective: Prospective
Official Title: Effect of Burosumab and 1-25 (OH) Vitamin D on Human Osteoclasts From Patients With Hypophosphatemic Rickets (HR)
Actual Study Start Date : January 20, 2021
Estimated Primary Completion Date : January 20, 2023
Estimated Study Completion Date : January 20, 2023

Group/Cohort Intervention/treatment
hypophosphatemic rickets patients
15 hypophosphatemic rickets patients older than 2 years will be included in this study
Other: blood sample
25 mL blood sample will be collected on citrate tubes for osteoclastic analysis.

Primary Outcome Measures :
  1. number of osteoclastic cells obtained after at the end of differentiation [ Time Frame: 1 day ]
    The analysis of osteoclastic differentiation will be obtained from the bone cells from patients with burosumab and/or 1-25 (OH) vitamin D

Biospecimen Retention:   Samples Without DNA
25 mL blood sample will be collected on citrate tubes for osteoclastic analysis.

Information from the National Library of Medicine

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Ages Eligible for Study:   2 Years and older   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
patients with hypophosphatemic rickets

Inclusion Criteria:

  • children from 2 yars-old to 18 years old and adults
  • patients with HR followed in the center of calcium and phosphorus metabolism rare diseases in Lyon-
  • Patients and parent / holder of parental authority who have been informed of the study and do not object to participate

Exclusion Criteria:

  • Patient being treated with oral corticosteroid or having received more than 3 months of corticosteroid treatment before surgery.
  • Patients under tutorship or curatorship
  • Pregnant and / or breastfeeding woman
  • Patient deprived of liberty

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT04184661

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Contact: Justine BACCHETTA, PU,PH 04 27 85 61 30 ext +33
Contact: Sacha FLAMMIER, project Manager 0472681349 ext +33

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Hôpital Femme mère enfant Recruiting
Bron, France, 69677
Contact: Justine BACCHETTA, PU,PH    04 27 85 61 30 ext +33   
Contact: Sacha FLAMMIER, project Manager    0472681349 ext +33   
Principal Investigator: Justine BACCHETTA, PU,PH         
Sponsors and Collaborators
Hospices Civils de Lyon
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Responsible Party: Hospices Civils de Lyon Identifier: NCT04184661    
Other Study ID Numbers: 69HCL19_0725
2019-A02914-53 ( Other Identifier: ID-RCB )
First Posted: December 3, 2019    Key Record Dates
Last Update Posted: January 22, 2021
Last Verified: January 2021

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Rickets, Hypophosphatemic
Familial Hypophosphatemic Rickets
Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Metabolic Diseases
Calcium Metabolism Disorders
Vitamin D Deficiency
Deficiency Diseases
Nutrition Disorders
Phosphorus Metabolism Disorders
Hypophosphatemia, Familial
Renal Tubular Transport, Inborn Errors
Kidney Diseases
Urologic Diseases
Metal Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn