Burosumab Improved Histomorphometric Measures of Osteomalacia in Adults with X-Linked Hypophosphatemia : A Phase 3, Single-Arm, International Trial

© 2019 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research..

In adults with X-linked hypophosphatemia (XLH), excess FGF23 impairs renal phosphate reabsorption and suppresses production of 1,25-dihydroxyvitamin D, resulting in chronic hypophosphatemia and persistent osteomalacia. Osteomalacia is associated with poor bone quality causing atraumatic fractures, pseudofractures, delayed fracture healing, and bone pain. Burosumab is a fully human monoclonal antibody against FGF23. UX023-CL304 is an ongoing, open-label, single-arm, phase 3 study investigating the efficacy of subcutaneous burosumab, 1.0 mg/kg administered every 4 weeks, in improving osteomalacia in adults with XLH who have not been treated for at least 2 years before enrollment. The primary endpoint was improvement in osteoid volume/bone volume assessed by transiliac bone biopsies obtained at baseline and week 48. Additional assessments included serum phosphorus, markers of bone turnover, fracture/pseudofracture healing, and safety. Fourteen subjects enrolled, 13 completed 48 weeks, and 11 completed paired biopsies. All osteomalacia-related histomorphometric measures improved significantly at week 48 (mean percent change: osteoid volume/bone volume, -54%, osteoid thickness, -32%, osteoid surface/bone surface, -26%, [median] mineralization lag time, -83%). Mean serum phosphorus concentration averaged across the mid-point of the dose cycle between weeks 0 and 24 was 3.3 mg/dL, a 50% increase from 2.2 mg/dL at baseline. Markers of bone formation and resorption increased at week 48 (least squares [LS] mean increase: P1NP, +77%; CTx, +36%; both p < 0.0001). All subjects had one or more treatment-emergent adverse event (AE). Most AEs were mild to moderate in severity. Two subjects experienced serious AEs (migraine; paresthesia) that were unrelated to treatment and resolved. Eleven subjects had 18 biopsy procedure-related AEs: 14 for pain, two for itch, and one each for headache and bandage irritation. No deaths or incidents of hyperphosphatemia occurred. In conclusion, by normalizing phosphate homeostasis, burosumab significantly improved osteomalacia in adults with XLH, which likely explains the improved fracture healing and amelioration of skeletal complications. © 2019 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Medienart:

E-Artikel

Erscheinungsjahr:

2019

Erschienen:

2019

Enthalten in:

Zur Gesamtaufnahme - volume:34

Enthalten in:

Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research - 34(2019), 12 vom: 15. Dez., Seite 2183-2191

Sprache:

Englisch

Beteiligte Personen:

Insogna, Karl L [VerfasserIn]
Rauch, Frank [VerfasserIn]
Kamenický, Peter [VerfasserIn]
Ito, Nobuaki [VerfasserIn]
Kubota, Takuo [VerfasserIn]
Nakamura, Akie [VerfasserIn]
Zhang, Lin [VerfasserIn]
Mealiffe, Matt [VerfasserIn]
San Martin, Javier [VerfasserIn]
Portale, Anthony A [VerfasserIn]

Links:

Volltext

Themen:

7Q7P4S7RRE
Antibodies, Monoclonal
Antibodies, Monoclonal, Humanized
BIOCHEMICAL MARKERS OF BONE TURNOVER
BONE HISTOMORPHOMETRY
Biomarkers
Burosumab
CLINICAL TRIALS
Clinical Trial, Phase III
FGF23 protein, human
Fibroblast Growth Factor-23
G9WJT6RD29
Journal Article
Multicenter Study
OSTEOMALACIA AND RICKETS
Research Support, Non-U.S. Gov't
THERAPEUTICS > OTHER

Anmerkungen:

Date Completed 10.09.2020

Date Revised 04.12.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1002/jbmr.3843

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM299810984