Case Report: Suboptimal response to standard-dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosing

Hypophosphatasia (HPP) is a rare, inherited metabolic disorder due to a deficiency of tissue-nonspecific alkaline phosphatase, characterized by defective bone and teeth mineralization with consequent problems, including respiratory failure in severe types of HPP. Severe patients exhibit other diseas...

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Main Authors: Danijela Petković Ramadža, Tamara Žigman, Mislav Čavka, Ivo Barić
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-06-01
Series:Frontiers in Endocrinology
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Online Access:https://www.frontiersin.org/articles/10.3389/fendo.2025.1587807/full
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author Danijela Petković Ramadža
Danijela Petković Ramadža
Tamara Žigman
Tamara Žigman
Mislav Čavka
Mislav Čavka
Ivo Barić
Ivo Barić
author_facet Danijela Petković Ramadža
Danijela Petković Ramadža
Tamara Žigman
Tamara Žigman
Mislav Čavka
Mislav Čavka
Ivo Barić
Ivo Barić
author_sort Danijela Petković Ramadža
collection DOAJ
description Hypophosphatasia (HPP) is a rare, inherited metabolic disorder due to a deficiency of tissue-nonspecific alkaline phosphatase, characterized by defective bone and teeth mineralization with consequent problems, including respiratory failure in severe types of HPP. Severe patients exhibit other disease-related manifestations, including neurological manifestations, which make HPP complex and difficult to manage. Enzyme replacement therapy with asfotase alfa is a disease-specific treatment for skeletal manifestations in pediatric patients. We present a patient with perinatal HPP who had a severe clinical course with respiratory insufficiency during infancy requiring a higher dose of asfotase alfa than recommended (12 mg/kg/week). After improvement of respiratory function and outgrowing the higher dose, the patient was maintained on the standard dose (6 mg/kg/week) from the age of 3 years. At 6 years of age, unexplained clinical and radiographic deterioration occurred while laboratory parameters remained normal. Following a traumatic humerus fracture that occurred after several months, asfotase alfa was increased to 10 mg/kg/week. Remarkable clinical improvement was observed and the patient regained the ability to walk unassisted 3 months after the dose correction. The rickets severity score changed from 10 to 3.5 within 14 months. No side effects from the higher drug dose have been noticed. The remaining challenge in this patient was a neurodevelopmental disorder. In conclusion, the standard dose of asfotase alfa was not sufficient to treat the skeletal manifestations of HPP in our patient, indicating that some perinatal HPP patients should be treated with higher doses to reach treatment goals. Although bone disease and patient outcomes have been improved with tailored drug doses, neurological manifestations of HPP remain challenging.
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spelling doaj-art-4a84c3138d97471ea06d21495fba10452025-08-20T03:31:01ZengFrontiers Media S.A.Frontiers in Endocrinology1664-23922025-06-011610.3389/fendo.2025.15878071587807Case Report: Suboptimal response to standard-dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosingDanijela Petković Ramadža0Danijela Petković Ramadža1Tamara Žigman2Tamara Žigman3Mislav Čavka4Mislav Čavka5Ivo Barić6Ivo Barić7Department of Pediatrics, University Hospital Centre Zagreb, Zagreb, CroatiaSchool of Medicine, University of Zagreb, Zagreb, CroatiaDepartment of Pediatrics, University Hospital Centre Zagreb, Zagreb, CroatiaSchool of Medicine, University of Zagreb, Zagreb, CroatiaSchool of Medicine, University of Zagreb, Zagreb, CroatiaDepartment of Diagnostic and Interventional Radiology, University Hospital Centre, Zagreb, CroatiaDepartment of Pediatrics, University Hospital Centre Zagreb, Zagreb, CroatiaSchool of Medicine, University of Zagreb, Zagreb, CroatiaHypophosphatasia (HPP) is a rare, inherited metabolic disorder due to a deficiency of tissue-nonspecific alkaline phosphatase, characterized by defective bone and teeth mineralization with consequent problems, including respiratory failure in severe types of HPP. Severe patients exhibit other disease-related manifestations, including neurological manifestations, which make HPP complex and difficult to manage. Enzyme replacement therapy with asfotase alfa is a disease-specific treatment for skeletal manifestations in pediatric patients. We present a patient with perinatal HPP who had a severe clinical course with respiratory insufficiency during infancy requiring a higher dose of asfotase alfa than recommended (12 mg/kg/week). After improvement of respiratory function and outgrowing the higher dose, the patient was maintained on the standard dose (6 mg/kg/week) from the age of 3 years. At 6 years of age, unexplained clinical and radiographic deterioration occurred while laboratory parameters remained normal. Following a traumatic humerus fracture that occurred after several months, asfotase alfa was increased to 10 mg/kg/week. Remarkable clinical improvement was observed and the patient regained the ability to walk unassisted 3 months after the dose correction. The rickets severity score changed from 10 to 3.5 within 14 months. No side effects from the higher drug dose have been noticed. The remaining challenge in this patient was a neurodevelopmental disorder. In conclusion, the standard dose of asfotase alfa was not sufficient to treat the skeletal manifestations of HPP in our patient, indicating that some perinatal HPP patients should be treated with higher doses to reach treatment goals. Although bone disease and patient outcomes have been improved with tailored drug doses, neurological manifestations of HPP remain challenging.https://www.frontiersin.org/articles/10.3389/fendo.2025.1587807/fullalkaline phosphatasehypophosphatasiaperinatal formasfotase alfaricketscentral nervous system
spellingShingle Danijela Petković Ramadža
Danijela Petković Ramadža
Tamara Žigman
Tamara Žigman
Mislav Čavka
Mislav Čavka
Ivo Barić
Ivo Barić
Case Report: Suboptimal response to standard-dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosing
Frontiers in Endocrinology
alkaline phosphatase
hypophosphatasia
perinatal form
asfotase alfa
rickets
central nervous system
title Case Report: Suboptimal response to standard-dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosing
title_full Case Report: Suboptimal response to standard-dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosing
title_fullStr Case Report: Suboptimal response to standard-dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosing
title_full_unstemmed Case Report: Suboptimal response to standard-dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosing
title_short Case Report: Suboptimal response to standard-dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosing
title_sort case report suboptimal response to standard dose asfotase alfa in perinatal hypophosphatasia indicates a need for individualized dosing
topic alkaline phosphatase
hypophosphatasia
perinatal form
asfotase alfa
rickets
central nervous system
url https://www.frontiersin.org/articles/10.3389/fendo.2025.1587807/full
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