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López-Romero LC, Broseta JJ, Muñoz-Castañeda JR, Hernández-Jaras J. X-Linked hypophosphatemia. Data from a Spanish adult population cohort. J Nephrol 2024:10.1007/s40620-024-01962-3. [PMID: 38837007 DOI: 10.1007/s40620-024-01962-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 04/24/2024] [Indexed: 06/06/2024]
Abstract
BACKGROUND X-linked hypophosphatemia (XLH) represents the most prevalent cause of hereditary hypophosphatemia. X-linked hypophosphatemia causes an elevation of fibroblast growth factor 23 (FGF23), a hormone responsible for inducing hyperphosphaturia, and reduced active vitamin D synthesis. Challenges in diagnosis and the absence of well-defined clinical guidelines have resulted in higher rates of late diagnoses. While numerous reports focus on pediatric X-linked hypophosphatemia patients, studies in adults are limited. METHODS Multicenter, cross-sectional, observational study of a cohort of adult patients diagnosed with X-linked hypophosphatemia. The study identified demographic, clinical, genetic, laboratory variables, treatments used, comorbidities, and complications. RESULTS Twenty patients diagnosed with X-linked hypophosphatemia were collected. The median age at diagnosis was 11 (1-56) years and at data collection was 44 (21-68) years. Fifty percent of cases were diagnosed in adulthood. Main clinical manifestation was osteoarticular pain, in 75% of cases, and no relation to age at diagnosis, height, phosphorus, or parathyroid hormone (PTH) levels was observed (p > 0.05). Lower limb deformities were associated with reduced stature and earlier diagnosis (p < 0.05). Sixty percent of patients reported pain requiring chronic medication and no significant correlation was found with other variables. Anxiety and depression were found in an important number of patients. FGF23 levels were not related to any of the clinical variables studied (p > 0.05). DISCUSSION This is the largest study on adult patients with X-linked hypophosphatemia in southern Europe. It may offer valuable insights into the natural progression and course of the condition in adults, which can aid in better clinical management.
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Affiliation(s)
- Luis Carlos López-Romero
- Department of Nephrology, Consorci Hospital General Universitari de València, Av. de Les Tres Creus, 2, 46014, València, Spain.
| | - José Jesús Broseta
- Department of Nephrology and Renal Transplantation, Hospital Clínic of Barcelona, Barcelona, Spain
| | - Juan R Muñoz-Castañeda
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Nephrology Clinical Management Unit, Reina Sofia University Hospital, University of Cordoba, Córdoba, Spain
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Dodamani MH, Kumar SC, Bhattacharjee S, Barnabas R, Kumar S, Ranjan Lila A, Samad Memon S, Karlekar M, A Patil V, R Bandgar T. Efficacy and safety of burosumab compared with conventional therapy in patients with X-linked hypophosphatemia: A systematic review. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2024; 68:e230242. [PMID: 38788147 PMCID: PMC11156178 DOI: 10.20945/2359-4292-2023-0242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 11/29/2023] [Indexed: 05/26/2024]
Abstract
Burosumab, a monoclonal antibody directed against the fibroblast growth factor 23 (FGF23), has been approved for the treatment of X-linked hypophosphatemia (XLH). We conducted a systematic review to compare the efficacy and safety of burosumab versus conventional therapy (phosphorus and calcitriol) on XLH treatment. After a comprehensive literature search on MEDLINE/PubMed and Embase, we found nine studies for inclusion in the analysis. Risk of bias was assessed, and a random-effects model was used to determine the effect size. Clinical, biochemical, and radiological parameters of disease severity before and after treatment were analyzed and expressed in standardized mean difference (SMD). Burosumab resulted in normalization of phosphate homeostasis with an increase in renal tubular phosphate reabsorption and significant resolution of skeletal lesions (change in Thacher's total rickets severity score SMD: -1.46, 95% confidence interval [CI]: -1.76 to -1.17, p < 0.001, improvement in deformities, and decline in serum alkaline phosphatase levels [SMD: 130.68, 95% CI: 125.26-136.1, p < 0.001)]. Conventional therapy led to similar improvements in all these parameters but to a lower degree. In adults, burosumab normalized phosphorus levels (SMD: 1.23, 95% CI: 0.98-1.47, p < 0.001) with resultant clinical improvement. Burosumab treatment was well tolerated, with only mild treatment-related adverse effects. The present review indicates a potential role for burosumab in improving rickets, deformities, and growth in children with XLH. Given its superior efficacy and safety profile, burosumab could be an effective therapeutic option in children. We suggest further studies comparing burosumab versus conventional therapy in children and adults with XLH.
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Affiliation(s)
| | | | - Samiksha Bhattacharjee
- Department of Clinical Pharmacology, Post-graduate Institute of Medical Education and Research, Chandigarh, India
| | - Rohit Barnabas
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Sandeep Kumar
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Anurag Ranjan Lila
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Saba Samad Memon
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Manjiri Karlekar
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Virendra A Patil
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India
| | - Tushar R Bandgar
- Department of Endocrinology, Seth G.S. Medical College & KEM Hospital, Mumbai, Maharashtra, India,
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Takashi Y, Kawanami D, Fukumoto S. Recent advances in fibroblast growth factor 23-related hypophosphatemic disorders. Curr Opin Endocrinol Diabetes Obes 2024:01266029-990000000-00093. [PMID: 38687287 DOI: 10.1097/med.0000000000000866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
PURPOSE OF REVIEW Fibroblast growth factor 23 (FGF23) is a hormone to reduce blood phosphate concentration. Excessive actions of FGF23 induce FGF23-related hypophosphatemic disorders, such as X-linked hypophosphatemic rickets (XLH) and tumor-induced osteomalacia (TIO). We will summarize recent advances in the diagnosis and treatment of FGF23-related hypophosphatemic disorders. RECENT FINDINGS The measurement of blood FGF23 is useful to make a diagnosis of FGF23-related hypophosphatemic disorders. It was reported that many patients with FGF23-related hypophosphatemic disorders, especially TIO, were misdiagnosed, therefore, it is necessary to enhance the awareness of these diseases. A novel method to inhibit excessive actions of FGF23 by a human monoclonal antibody for FGF23, burosumab, has been approved in several countries. In more long-term observation than clinical trials, burosumab has also been shown to improve biochemical abnormalities and symptoms of rickets/osteomalacia. Following these advances, several registries and consensus recommendations on FGF23-related hypophosphatemic disorders, especially XLH, have been established in each country or region. SUMMARY Further long-term effects of burosumab and the precise mechanism of FGF23 overproduction in patients with FGF23-related hypophosphatemic disorders need to be clarified in the future studies.
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Affiliation(s)
- Yuichi Takashi
- Department of Endocrinology and Diabetes, Fukuoka University School of Medicine
| | - Daiji Kawanami
- Department of Endocrinology and Diabetes, Fukuoka University School of Medicine
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Martínez-Heredia L, Canelo-Moreno JM, García-Fontana B, Muñoz-Torres M. Non-Classical Effects of FGF23: Molecular and Clinical Features. Int J Mol Sci 2024; 25:4875. [PMID: 38732094 PMCID: PMC11084844 DOI: 10.3390/ijms25094875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 04/21/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
This article reviews the role of fibroblast growth factor 23 (FGF23) protein in phosphate metabolism, highlighting its regulation of vitamin D, parathyroid hormone, and bone metabolism. Although it was traditionally thought that phosphate-calcium homeostasis was controlled exclusively by parathyroid hormone (PTH) and calcitriol, pathophysiological studies revealed the influence of FGF23. This protein, expressed mainly in bone, inhibits the renal reabsorption of phosphate and calcitriol formation, mediated by the α-klotho co-receptor. In addition to its role in phosphate metabolism, FGF23 exhibits pleiotropic effects in non-renal systems such as the cardiovascular, immune, and metabolic systems, including the regulation of gene expression and cardiac fibrosis. Although it has been proposed as a biomarker and therapeutic target, the inhibition of FGF23 poses challenges due to its potential side effects. However, the approval of drugs such as burosumab represents a milestone in the treatment of FGF23-related diseases.
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Affiliation(s)
- Luis Martínez-Heredia
- Instituto de Investigación Biosanitaria de Granada, 18014 Granada, Spain;
- Biomedical Research Network in Fragility and Healthy Aging (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | | | - Beatriz García-Fontana
- Instituto de Investigación Biosanitaria de Granada, 18014 Granada, Spain;
- Biomedical Research Network in Fragility and Healthy Aging (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Endocrinology and Nutrition Unit, University Hospital Clínico San Cecilio, 18016 Granada, Spain
- Department of Cell Biology, University of Granada, 18016 Granada, Spain
| | - Manuel Muñoz-Torres
- Instituto de Investigación Biosanitaria de Granada, 18014 Granada, Spain;
- Biomedical Research Network in Fragility and Healthy Aging (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Endocrinology and Nutrition Unit, University Hospital Clínico San Cecilio, 18016 Granada, Spain
- Department of Medicine, University of Granada, 18016 Granada, Spain
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Baroncelli GI, Comberiati P, Aversa T, Baronio F, Cassio A, Chiarito M, Cosci o di Coscio M, De Sanctis L, Di Iorgi N, Faienza MF, Fintini D, Franceschi R, Kalapurackal M, Longhi S, Mariani M, Pitea M, Secco A, Tessaris D, Vierucci F, Wasniewska M, Weber G, Mora S. Diagnosis, treatment, and management of rickets: a position statement from the Bone and Mineral Metabolism Group of the Italian Society of Pediatric Endocrinology and Diabetology. Front Endocrinol (Lausanne) 2024; 15:1383681. [PMID: 38706696 PMCID: PMC11066174 DOI: 10.3389/fendo.2024.1383681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/03/2024] [Indexed: 05/07/2024] Open
Abstract
Rickets results from impaired mineralization of growing bone due to alterations in calcium and phosphate homeostasis. Clinical signs of rickets are related to the age of the patient, the duration of the disease, and the underlying disorder. The most common signs of rickets are swelling of the wrists, knees or ankles, bowing of the legs (knock-knees, outward bowing, or both) and inability to walk. However, clinical features alone cannot differentiate between the various forms of rickets. Rickets includes a heterogeneous group of acquired and inherited diseases. Nutritional rickets is due to a deficiency of vitamin D, dietary calcium or phosphate. Mutations in genes responsible for vitamin D metabolism or function, the production or breakdown of fibroblast growth factor 23, renal phosphate regulation, or bone mineralization can lead to the hereditary form of rickets. This position paper reviews the relevant literature and presents the expertise of the Bone and Mineral Metabolism Group of the Italian Society of Pediatric Endocrinology and Diabetology (SIEDP). The aim of this document is to provide practical guidance to specialists and healthcare professionals on the main criteria for diagnosis, treatment, and management of patients with rickets. The various forms of rickets are discussed, and detailed references for the discussion of each form are provided. Algorithms to guide the diagnostic approach and recommendations to manage patients with rare forms of hereditary rickets are proposed.
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Affiliation(s)
- Giampiero I. Baroncelli
- Pediatric and Adolescent Endocrinology, Division of Pediatrics, Department of Obstetrics, Gynecology and Pediatrics, University Hospital, Pisa, Italy
| | - Pasquale Comberiati
- Pediatric and Adolescent Endocrinology, Division of Pediatrics, Department of Obstetrics, Gynecology and Pediatrics, University Hospital, Pisa, Italy
- Department of Clinical and Experimental Medicine, Section of Paediatrics, University of Pisa, Pisa, Italy
| | - Tommaso Aversa
- Department of Human Pathology of Adulthood and Childhood, University of Messina, Messina, Italy
- Pediatric Unit, University Hospital “G. Martino”, Messina, Italy
| | - Federico Baronio
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Alessandra Cassio
- Pediatric Unit, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
- Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
| | - Mariangela Chiarito
- Pediatric Unit, Department of Precision and Regenerative Medicine and Ionian Area, University “A. Moro” of Bari, Bari, Italy
| | - Mirna Cosci o di Coscio
- Pediatric and Adolescent Endocrinology, Division of Pediatrics, Department of Obstetrics, Gynecology and Pediatrics, University Hospital, Pisa, Italy
| | - Luisa De Sanctis
- Division of Pediatric Endocrinology, Department of Public Health and Pediatrics, University of Turin, Regina Margherita Children’s Hospital, Turin, Italy
| | - Natascia Di Iorgi
- Department of Pediatrics, IRCCS Istituto Giannina Gaslini, Genova, Italy
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
| | - Maria Felicia Faienza
- Pediatric Unit, Department of Precision and Regenerative Medicine and Ionian Area, University “A. Moro” of Bari, Bari, Italy
| | - Danilo Fintini
- Endocrinology and Diabetology Unit, Bambino Gesù Children Hospital, IRCCS, Rome, Italy
| | - Roberto Franceschi
- Department of Pediatrics, Santa Chiara Hospital of Trento, APSS, Trento, Italy
| | - Mila Kalapurackal
- Department of Pediatrics, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Silvia Longhi
- Department of Pediatrics, Hospital of Bolzano (SABES-ASDAA), Teaching Hospital of Paracelsus Medical University (PMU), Bolzano, Italy
| | - Michela Mariani
- Endocrinology and Diabetology Unit, Bambino Gesù Children Hospital, IRCCS, Rome, Italy
| | - Marco Pitea
- Pediatric Endocrinology Unit, Department of Pediatrics, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Andrea Secco
- Pediatric and Pediatric Emergency Unit, Children Hospital, Azienda Ospedaliera SS Antonio e Biagio e C. Arrigo, Alessandria, Italy
| | - Daniele Tessaris
- Division of Pediatric Endocrinology, Department of Public Health and Pediatrics, University of Turin, Regina Margherita Children’s Hospital, Turin, Italy
| | | | - Malgorzata Wasniewska
- Department of Human Pathology of Adulthood and Childhood, University of Messina, Messina, Italy
| | - Giovanna Weber
- Pediatric Endocrinology Unit, Department of Pediatrics, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Stefano Mora
- Laboratory of Pediatric Endocrinology, Department of Pediatrics, IRCCS Ospedale San Raffaele, Milan, Italy
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Wagner E, Bertholet-Thomas A, Romier M, Loin L, Lemoine S, Vignot E, Flammier S, Garnier C, De-Mul A, Feutrier C, Juillard S, Thivichon-Prince B, Lienhart G, Bacchetta J. X-linked hypophosphatemia: The value of feedback focus groups to assess patient and caregiver needs. Eur J Med Genet 2024; 68:104912. [PMID: 38296036 DOI: 10.1016/j.ejmg.2024.104912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 11/22/2023] [Accepted: 01/20/2024] [Indexed: 02/09/2024]
Abstract
X-linked hypophosphatemia (XLH) is a rare, multi-systemic, invalidating disease requiring a multi-disciplinary approach. No specific action in XLH, neither for the patients' specific needs nor for the methodology for the evaluation of these were found. Thus, to identify the needs of XLH patients and their caregivers, we organised focus groups in our reference centre with a view to build educational sessions. Focus groups including either XLH children, XLH adults, or caregivers ran in parallel. Each group was led by a person trained in therapeutic education (nurse, paediatric nephrologist) with another healthcare provider specialised in XLH (rheumatologist, nephrologist). One additional person with knowledge of XLH (clinical research associate, paediatric resident) took minutes. The duration of each session was 1.5h; XLH patients/caregivers were asked to answer age-adapted "open questions" on their daily life and quality of life. At the end, a global restitution was made. The needs identified were later grouped and analysed, which allowed us to build the educational sessions. The XLH children group included 5 children, the XLH adults group included 10 adults, and the caregivers group included 6 parents or partners. Major needs were identified: knowledge of XLH, treatment, dental care and adapted physical activity, with additional questions on socio-professional adaptations and financial support in adults. Partner patients were also identified to co-build the support programme. The study allowed us to identify the needs of XLH patients and their caregivers using the focus group method and then, using these needs, to build educational sessions and a therapeutic education programme for XLH patients.
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Affiliation(s)
- Estelle Wagner
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France.
| | - Aurélia Bertholet-Thomas
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France; INSERM 1033, LYOS, Prévention des Maladies Osseuses, Lyon, France
| | - Mélanie Romier
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France
| | - Laure Loin
- Transversal Unit of Therapeutic Patient Education of Department of Rhône, Hospices Civils de Lyon, Lyon, France
| | - Sandrine Lemoine
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France; Faculté de Médecine Lyon Est, Université Claude Bernard Lyon 1, Lyon, France
| | - Emmanuelle Vignot
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France; Rheumatology, Edouard Herriot Hospital, Lyon, France
| | - Sacha Flammier
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France
| | - Charlotte Garnier
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France
| | - Aurélie De-Mul
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France
| | - Corinne Feutrier
- Transversal Unit of Therapeutic Patient Education of Department of Rhône, Hospices Civils de Lyon, Lyon, France
| | - Sandrine Juillard
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France
| | - Béatrice Thivichon-Prince
- Centre de Compétence Maladies Rares Orales et dentaires, Pôle d'odontologie de Lyon, Hospices Civils de Lyon, Lyon, France
| | - Guillemette Lienhart
- Centre de Compétence Maladies Rares Orales et dentaires, Pôle d'odontologie de Lyon, Hospices Civils de Lyon, Lyon, France
| | - Justine Bacchetta
- Centre de Référence des Maladies Rares du Calcium et du Phosphore, Centre de Référence des Maladies Rénales Rares, Filières OSCAR et ORKID, Filières Européennes Bond et ERKNet, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Lyon, France; INSERM 1033, LYOS, Prévention des Maladies Osseuses, Lyon, France; Faculté de Médecine Lyon Est, Université Claude Bernard Lyon 1, Lyon, France.
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Goyal A, Tandon N. Burosumab: Current status and future prospects. Best Pract Res Clin Endocrinol Metab 2024; 38:101826. [PMID: 37858479 DOI: 10.1016/j.beem.2023.101826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Hypophosphatemic rickets/osteomalacia caused by FGF23 excess is conventionally treated with multiple doses of inorganic phosphate salts and active vitamin D analogs. However, conventional therapy targets the consequences of elevated FGF23 and not the elevated FGF23 itself and is associated with poor adherence and long-term complications such as nephrocalcinosis and secondary/tertiary hyperparathyroidism. Burosumab is a fully human IgG1 monoclonal antibody that binds to and neutralises FGF-23, thereby leading to improvement in phosphate homeostasis and healing of rickets and osteomalacia. Data from phase 2 and 3 trials report overall safety and efficacy and Burosumab is now FDA approved for treatment of XLH and TIO in children and adults. Cost and absence of long-term data are major issues with Burosumab which should be addressed in near future. At present, experts recommend Burosumab use in patients with severe disease or those with mild-moderate disease and a failed response to a trial of conventional therapy.
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Affiliation(s)
- Alpesh Goyal
- Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, Convergence Block, Room no 7002, Seventh Floor, New Delhi 110029, India.
| | - Nikhil Tandon
- Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, Convergence Block, Room no 7002, Seventh Floor, New Delhi 110029, India.
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Serra AL, Russmann S, Henschkowski-Serra J. [Significance of phosphate in internal medicine]. Dtsch Med Wochenschr 2024; 149:93-100. [PMID: 38262403 DOI: 10.1055/a-2047-3665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
Phosphate is essential for bone metabolism and for energy provision. Phosphate homeostasis is achieved by hormonal feedback mechanisms, predominantly parathyroid hormone, fibroblast growth factor 23 and calcitriol, with renal phosphate absorption taking on a special role. Although even large deviations from the serum normal range are rarely symptomatic, the health consequences can be significant. Essentially, the clinically relevant disturbances in phosphate balance can be attributed to three mechanisms: 1. shifts of phosphate between the extracellular space and the cytosol; 2. inadequate phosphate reabsorption in the kidney; 3. decreased intestinal phosphate absorption. Knowledge of physiology enables diagnosis and therapy of phosphate disorders.
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Jurina A, Kasumović D, Delimar V, Filipec Kanižaj T, Japjec M, Dujmović T, Vučić Lovrenčić M, Starešinić M. Fibroblast growth factor 23 and its role in bone diseases. Growth Factors 2024; 42:1-12. [PMID: 37906060 DOI: 10.1080/08977194.2023.2274579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 10/18/2023] [Indexed: 11/02/2023]
Abstract
Fibroblast growth factor 23 (FGF23) has been casually linked to numerous hypophosphatemic bone diseases, however connection with bone loss or fragility fractures is still a matter of debate. The purpose of this review is to explore and summarise the known actions of FGF23 in various pathological bone conditions. Besides implication in bone mineralisation, elevated FGF23 showed a pathological effecton bone remodelling, primarily by inhibiting osteoblast function. Unlike the weak association with bone mineral density, high values of FGF23 have been connected with fragility fracture prevalence. This review shows that its effects on bone are concomitantly present on multiple levels, affecting both qualitative and quantitative part of bone strength, eventually leading to impaired bone strength and increased tendency of fractures. Recognising FGF23 as a risk factor for the development of bone diseases and correcting its levels could lead to the reduction of morbidity and mortality in specific groups of patients.
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Affiliation(s)
- Andrija Jurina
- Department of Surgery, Division of General and Sport Traumatology and Orthopaedics, Merkur University Hospital, Zagreb, Croatia
| | - Dino Kasumović
- Department of Internal Medicine, Division of Nephrology and Dialysis, Dubrava University Hospital, Zagreb, Croatia
| | - Valentina Delimar
- Special Hospital for Medical Rehabilitation KrapinskeToplice, KrapinskeToplice, Croatia
| | - Tajana Filipec Kanižaj
- Department of Internal Medicine, Division of Gastroenterology, Merkur University Hospital, Zagreb, Croatia
- School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Mladen Japjec
- Department of Surgery, Division of General and Sport Traumatology and Orthopaedics, Merkur University Hospital, Zagreb, Croatia
| | - Tomislav Dujmović
- Department of Surgery, Division of General and Sport Traumatology and Orthopaedics, Merkur University Hospital, Zagreb, Croatia
| | - Marijana Vučić Lovrenčić
- Department of Clinical Chemistry and Laboratory Medicine, Merkur University Hospital, Zagreb, Croatia
| | - Mario Starešinić
- Department of Surgery, Division of General and Sport Traumatology and Orthopaedics, Merkur University Hospital, Zagreb, Croatia
- School of Medicine, University of Zagreb, Zagreb, Croatia
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10
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Ward LM, Högler W, Glorieux FH, Portale AA, Whyte MP, Munns CF, Nilsson O, Simmons JH, Padidela R, Namba N, Cheong HI, Sochett E, Muroya K, Tanaka H, Pitukcheewanont P, Gottesman GS, Biggin A, Perwad F, Chen A, Lawrence Merritt II J, Imel EA. Burosumab vs conventional therapy in children with X-linked hypophosphatemia: results of the open-label, phase 3 extension period. JBMR Plus 2024; 8:ziad001. [PMID: 38690124 PMCID: PMC11059996 DOI: 10.1093/jbmrpl/ziad001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/06/2023] [Indexed: 05/02/2024] Open
Abstract
In a randomized, open-label phase 3 study of 61 children aged 1-12 years old with X-linked hypophosphatemia (XLH) previously treated with conventional therapy, changing to burosumab every 2 weeks (Q2W) for 64 weeks improved the phosphate metabolism, radiographic rickets, and growth compared with conventional therapy. In this open-label extension period (weeks 64-88), 21 children continued burosumab Q2W at the previous dose or crossed over from conventional therapy to burosumab starting at 0.8 mg/kg Q2W with continued clinical radiographic assessments through week 88. Efficacy endpoints and safety observations were summarized descriptively for both groups (burosumab continuation, n = 6; crossover, n = 15). At week 88 compared with baseline, improvements in the following outcomes were observed in the burosumab continuation and crossover groups, respectively: mean (SD) RGI-C rickets total score (primary outcome), +2.11 (0.27) and +1.89 (0.35); mean (SD) RGI-C lower limb deformity score, +1.61 (0.91) and +0.73 (0.82); and mean (SD) height Z-score + 0.41 (0.50) and +0.08 (0.34). Phosphate metabolism normalized rapidly in the crossover group and persisted in the continuation group. Mean (SD) serum alkaline phosphatase decreased from 169% (43%) of the upper limit of normal (ULN) at baseline to 126% (51%) at week 88 in the continuation group and from 157% (33%) of the ULN at baseline to 111% (23%) at week 88 in the crossover group. During the extension period, treatment-emergent adverse events (AEs) were reported in all 6 children in the burosumab continuation group and 14/15 children in the crossover group. The AE profiles in the randomized and extension periods were similar, with no new safety signals identified. Improvements from baseline in radiographic rickets continued in the extension period among children with XLH who remained on burosumab. Children who crossed over from conventional therapy to burosumab demonstrated a rapid improvement in phosphate metabolism and improved rickets healing over the ensuing 22 weeks.
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Affiliation(s)
- Leanne M Ward
- Department of Pediatrics, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, K1H 8L1, Canada
| | - Wolfgang Högler
- Department of Paediatrics and Adolescent Medicine, Johannes Kepler University Linz, 4040 Linz, Austria
- Institute of Metabolism and Systems Research, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom
| | - Francis H Glorieux
- Department of Surgery, Pediatrics, and Human Genetics, Shriners Hospitals for Children and McGill University, Montreal, Quebec, H4A 0A9, Canada
| | - Anthony A Portale
- Department of Pediatrics, University of California, San Francisco, CA, 94158, United States
| | - Michael P Whyte
- Shriners Hospitals for Children St Louis, St Louis, MO, 63110, United States
| | - Craig F Munns
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, 4072, Australia
- Faculty of Medicine, Child Health Research Centre, The University of Queensland, Brisbane, Queensland, 4072, Australia
- Department of Endocrinology and Diabetes, Queensland Children’s Hospital, Brisbane, Queensland, 4072, Australia
| | - Ola Nilsson
- Division of Pediatric Endocrinology, Department of Women’s and Children’s Health, Center for Molecular Medicine, Karolinska Institutet and University Hospital, SE-17176 Stockholm, Sweden
- Department of Pediatrics, School of Medical Sciences, Örebro University and University Hospital, S-701 82 Örebro, Sweden
| | - Jill H Simmons
- Division of Endocrinology and Diabetes, Department of Pediatrics, Vanderbilt University School of Medicine, Vanderbilt University, Nashville, TN, 37232, United States
| | - Raja Padidela
- Department of Paediatric Endocrinology, Royal Manchester Children’s Hospital, Manchester, M13 9WL, United Kingdom
| | - Noriyuki Namba
- Department of Pediatrics, Osaka Hospital, Japan Community Healthcare Organization, Osaka, 553-0003, Japan
- Osaka University Graduate School of Medicine, Osaka, 565-0871, Japan
| | - Hae Il Cheong
- Department of Pediatrics, Hallym University Sacred Heart Hospital, Dongan-gu, Anyang, 14068, South Korea
| | - Etienne Sochett
- Department of Pediatrics, Hospital for Sick Children, Toronto, Ontario, M5G 1E8, Canada
| | - Koji Muroya
- Department of Endocrinology, Kanagawa Children’s Medical Center, Yokohama, Kanagawa 232-0066, Japan
| | - Hiroyuki Tanaka
- Division of Pediatrics, Okayama Saiseikai General Hospital Outpatient Center, Kita-ku, Okayama, 700-8511, Japan
| | - Pisit Pitukcheewanont
- Center of Endocrinology, Diabetes and Metabolism, Children’s Hospital of Los Angeles, Los Angeles, CA, 90027, United States
| | - Gary S Gottesman
- Shriners Hospitals for Children St Louis, St Louis, MO, 63110, United States
| | - Andrew Biggin
- Department of Endocrinology, The University of Sydney Children’s Hospital Westmead Clinical School, The Children’s Hospital at Westmead, Westmead, New South Wales, 2145, Australia
| | - Farzana Perwad
- Department of Pediatrics, University of California, San Francisco, CA, 94158, United States
| | - Angel Chen
- Ultragenyx Pharmaceutical Inc., Novato, CA, 94949, United States
| | | | - Erik A Imel
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, 46202, United States
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11
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Wang S, Wang X, He M, Li Y, Xiao M, Ma H. Efficacy and Safety of Burosumab in X-linked Hypophosphatemia. J Clin Endocrinol Metab 2023; 109:293-302. [PMID: 37497620 DOI: 10.1210/clinem/dgad440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/06/2022] [Accepted: 07/25/2023] [Indexed: 07/28/2023]
Abstract
CONTEXT Burosumab is approved for the treatment of X-linked hypophosphatemia (XLH). OBJECTIVE To assess the efficacy and safety of burosumab in XLH patients, we conducted a systematic review and meta-analysis. METHODS We searched PubMed, the Cochrane Library, Embase, ClinicalTrials.gov, and Web of Science for studies on the use of burosumab in patients with XLH. Meta-analysis of randomized controlled trials (RCTs) and single-arm trials (SATs) was done to explore burosumab treatment on the efficacy and safety of XLH. RESULTS Of the 8 eligible articles, 5 were from RCTs and 3 were from SATs. Compared with the control group in RCTs, serum phosphorus level was significantly increased in the burosumab group (0.52 mg/dL, 95% CI 0.24-0.80 mg/dL). A meta-analysis of the burosumab arms in all trials revealed significant increase in serum phosphorus levels (0.78 mg/dL, 95% CI 0.61-0.96 mg/dL), TmP/GFR (0.86 mg/dL, 95% CI 0.60-1.12 mg/dL), and 1,25-dihydroxyvitamin D level (13.23 pg/mL, 95% CI 4.82-21.64 pg/mL) as well. Changes in secondary events also validated the effects of burosumab treatment. Compared with the control group, in RCTs, the safety profile of burosumab is not much different from the control group. Data of the single-arm combined group demonstrated the incidence of any treatment emergency adverse event (TEAE) and the related TEAE rate were high, but the severity of most adverse events is mild to moderate, and the rate of serious TEAE is low. CONCLUSION This study suggests that burosumab can be an option for patients with XLH and did not significantly increase the incidence of adverse events.
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Affiliation(s)
- Sen Wang
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Xiaoqin Wang
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Miao He
- Department of Neurology, The Ninth Clinical Medical College Affiliated to Shanxi Medical University, Taiyuan 030000, China
| | - Yuanfen Li
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Minghui Xiao
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Houxun Ma
- Department of Geriatrics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
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12
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Abdullah A, Wuersching SN, Kollmuss M, Poxleitner P, Dewenter I, Brandenburg LS, Steybe D, Fegg FN, Smolka W, Otto S, Obermeier KT. X-Linked Hypophosphatemia: Does Targeted Therapy Modify Dental Impairment? J Clin Med 2023; 12:7546. [PMID: 38137614 PMCID: PMC10744150 DOI: 10.3390/jcm12247546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/22/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
X-linked hypophosphatemia is a rare, hereditary disorder that significant influences teeth and alveolar bone. The first clinical sign leading to the diagnosis of X-linked hypophosphatemia is often dental impairment with dental abscesses and dentin mineralization defects. Genetic analysis helped find the responsible gene and therefore opened up new ways of therapeutically managing X-linked hypophosphatemia. The human monoclonal antibody Burosumab represents a milestone in the targeted therapy of this hereditary disease by directly addressing its pathophysiology. Targeted therapy has been shown to improve skeletal impairment, pain, and phosphate metabolism. However, the influence of this new therapy on dental impairment has only been addressed in a few recent studies with varying results. Therefore, in this review, we aim to summarize the dental phenotype and analyze the different treatment modalities with a focus on dental impairment.
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Affiliation(s)
- Anusha Abdullah
- Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, Ludwig Maximilians University, 80337 Munich, Germany
| | - Sabina Noreen Wuersching
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Maximilian Kollmuss
- Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Philipp Poxleitner
- Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, Ludwig Maximilians University, 80337 Munich, Germany
| | - Ina Dewenter
- Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, Ludwig Maximilians University, 80337 Munich, Germany
| | - Leonard Simon Brandenburg
- Medical Center—University of Freiburg, Center for Dental Medicine, Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Freiburg, Hugstetter Str. 55, 79106 Freiburg, Germany
| | - David Steybe
- Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, Ludwig Maximilians University, 80337 Munich, Germany
| | - Florian Nepomuk Fegg
- Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, Ludwig Maximilians University, 80337 Munich, Germany
| | - Wenko Smolka
- Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, Ludwig Maximilians University, 80337 Munich, Germany
| | - Sven Otto
- Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, Ludwig Maximilians University, 80337 Munich, Germany
| | - Katharina Theresa Obermeier
- Department of Oral and Maxillofacial Surgery and Facial Plastic Surgery, Ludwig Maximilians University, 80337 Munich, Germany
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13
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Lira Dos Santos EJ, Nakajima K, Po J, Hanai A, Zhukouskaya V, Biosse Duplan M, Linglart A, Shimada T, Chaussain C, Bardet C. Dental impact of anti-fibroblast growth factor 23 therapy in X-linked hypophosphatemia. Int J Oral Sci 2023; 15:53. [PMID: 38052774 DOI: 10.1038/s41368-023-00259-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 11/03/2023] [Accepted: 11/05/2023] [Indexed: 12/07/2023] Open
Abstract
Elevated fibroblast growth factor 23 (FGF23) in X-linked hypophosphatemia (XLH) results in rickets and phosphate wasting, manifesting by severe bone and dental abnormalities. Burosumab, a FGF23-neutralizing antibody, an alternative to conventional treatment (phosphorus and active vitamin D analogs), showed significant improvement in the long bone phenotype. Here, we examined whether FGF23 antibody (FGF23-mAb) also improved the dentoalveolar features associated with XLH. Four-week-old male Hyp mice were injected weekly with 4 or 16 mg·kg-1 of FGF23-mAb for 2 months and compared to wild-type (WT) and vehicle (PBS) treated Hyp mice (n = 3-7 mice). Micro-CT analyses showed that both doses of FGF23-mAb restored dentin/cementum volume and corrected the enlarged pulp volume in Hyp mice, the higher concentration resulting in a rescue similar to WT levels. FGF23-mAb treatment also improved alveolar bone volume fraction and mineral density compared to vehicle-treated ones. Histology revealed improved mineralization of the dentoalveolar tissues, with a decreased amount of osteoid, predentin and cementoid. Better periodontal ligament attachment was also observed, evidenced by restoration of the acellular cementum. These preclinical data were consistent with the retrospective analysis of two patients with XLH showing that burosumab treatment improved oral features. Taken together, our data show that the dentoalveolar tissues are greatly improved by FGF23-mAb treatment, heralding its benefit in clinics for dental abnormalities.
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Affiliation(s)
- Elis J Lira Dos Santos
- Université Paris Cité, Institut des maladies musculo-squelettiques, Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d'Imagerie du Vivant (PIV), Montrouge, France
| | - Kenta Nakajima
- R&D Division, Kyowa Kirin, Co., Ltd, 3-6-6 Asahi-machi, Machida-shi, Tokyo, Japan
| | - Julien Po
- Université Paris Cité, Institut des maladies musculo-squelettiques, Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d'Imagerie du Vivant (PIV), Montrouge, France
| | - Ayako Hanai
- R&D Division, Kyowa Kirin, Co., Ltd, 3-6-6 Asahi-machi, Machida-shi, Tokyo, Japan
| | - Volha Zhukouskaya
- Université Paris Cité, Institut des maladies musculo-squelettiques, Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d'Imagerie du Vivant (PIV), Montrouge, France
| | - Martin Biosse Duplan
- Université Paris Cité, Institut Imagine, INSERM UMR 1163, Paris, France
- AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Dental Medicine Department, Bretonneau Hospital, GHN-Université Paris Cité, Paris, France
| | - Agnès Linglart
- Paris-Saclay University, AP-HP, INSERM U1185, DMU SEA, Endocrinology and Diabetes for Children, Reference Center for Rare Diseases of the Calcium and Phosphate Metabolism, OSCAR filière, EndoRare, and BOND ERNs, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France
| | - Takashi Shimada
- Medical Affairs Department, Kyowa Kirin, Co., Ltd, 1-9-2 Otemachi, Chiyoda-ku, Tokyo, Japan
| | - Catherine Chaussain
- Université Paris Cité, Institut des maladies musculo-squelettiques, Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d'Imagerie du Vivant (PIV), Montrouge, France
- AP-HP, Reference Center for Rare Disorders of the Calcium and Phosphate Metabolism, Dental Medicine Department, Bretonneau Hospital, GHN-Université Paris Cité, Paris, France
| | - Claire Bardet
- Université Paris Cité, Institut des maladies musculo-squelettiques, Laboratory Orofacial Pathologies, Imaging and Biotherapies URP2496 and FHU-DDS-Net, Dental School, and Plateforme d'Imagerie du Vivant (PIV), Montrouge, France.
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14
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Levy-Shraga Y, Levi S, Regev R, Gal S, Brener A, Lebenthal Y, Gillis D, Strich D, Zung A, Cleper R, Borovitz Y, Bello R, Tenenbaum A, Zadik Z, Davidovits M, Zeitlin L, Tiosano D. Linear growth of children with X-linked hypophosphatemia treated with burosumab: a real-life observational study. Eur J Pediatr 2023; 182:5191-5202. [PMID: 37707589 DOI: 10.1007/s00431-023-05190-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/30/2023] [Accepted: 09/02/2023] [Indexed: 09/15/2023]
Abstract
To assess the long-term efficacy of burosumab for pediatric patients with X-linked hypophosphatemia, focusing on linear growth. This multi-center retrospective study included 35 pediatric patients who began treatment with burosumab between January 2018 and January 2021. We collected clinical data, anthropometric measurements, laboratory results, and Rickets Severity Score (RSS), from 2 years prior to treatment initiation and up to 4 years after. Burosumab was initiated at a mean age of 7.5 ± 4.4 years (range 0.6-15.9), with a mean initial dose of 0.8 ± 0.3 mg/kg, which was subsequently increased to 1.1 ± 0.4 mg/kg. The patients were followed for 2.9 ± 1.4 years (range 1-4) after initiating burosumab. Serum phosphorus levels increased from 2.7 ± 0.8 mg/dl at burosumab initiation to 3.4 ± 0.6 mg/dl after 3 months and remained stable (p < 0.001). Total reabsorption of phosphorus increased from 82.0 ± 6.8 to 90.1 ± 5.3% after 12 months of treatment (p = 0.041). The RSS improved from 1.7 ± 1.0 at burosumab initiation to 0.5 ± 0.6 and 0.3 ± 0.6 after 12 and 24 months, respectively (p < 0.001). Both height z-score and weight z-score improved from burosumab initiation to the end of the study: from - 2.07 ± 1.05 to - 1.72 ± 1.04 (p < 0.001) and from - 0.51 ± 1.12 to - 0.11 ± 1.29 (p < 0.001), respectively. Eight children received growth hormone combined with burosumab treatment. Height z-score improved among those who received growth hormone (from - 2.33 ± 1.12 to - 1.94 ± 1.24, p = 0.042) and among those who did not (from - 2.01 ± 1.01 to - 1.66 ± 1.01, p = 0.001). CONCLUSION Burosumab treatment in a real-life setting improved phosphate homeostasis and rickets severity and enhanced linear growth. WHAT IS KNOWN • Compared to conventional therapy, burosumab treatment has been shown to increase serum phosphate levels and reduce the severity of rickets. • The effect of burosumab on growth is still being study. WHAT IS NEW • Height z-score improved between the start of burosumab treatment and the end of the study (-2.07 ± 1.05 vs. -1.72 ± 1.04, p < 0.001). • Eight children received burosumab combined with growth hormone treatment without side effects during the concomitant treatments.
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Affiliation(s)
- Yael Levy-Shraga
- Pediatric Endocrinology Unit, The Edmond and Lily Safra Children's Hospital, Chaim Sheba Medical Center, Tel Hashomer, 52621, Israel.
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Shelly Levi
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Institute of Pediatric Nephrology, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Ravit Regev
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Shoshana Gal
- Division of Pediatric Endocrinology, Ruth Rappaport Children's Hospital, Rambam Medical Center, Haifa, Israel
- Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Avivit Brener
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yael Lebenthal
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Endocrinology and Diabetes Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - David Gillis
- Pediatric Endocrinology Unit, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
- Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
| | - David Strich
- Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
- Department of Pediatrics, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Amnon Zung
- Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
- Pediatrics Department, Kaplan Medical Center, Rehovot, Israel
| | - Roxana Cleper
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Nephrology Unit, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yael Borovitz
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Institute of Pediatric Nephrology, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Rachel Bello
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Shafer Institute for Endocrinology and Diabetes, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Ariel Tenenbaum
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Shafer Institute for Endocrinology and Diabetes, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Zvi Zadik
- Faculty of Medicine, Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
- Pediatrics Department, Kaplan Medical Center, Rehovot, Israel
| | - Miriam Davidovits
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Institute of Pediatric Nephrology, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Leonid Zeitlin
- The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Pediatric Orthopedic Department, Dana-Dwek Children's Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Dov Tiosano
- Division of Pediatric Endocrinology, Ruth Rappaport Children's Hospital, Rambam Medical Center, Haifa, Israel
- Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
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15
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Seefried L, Alzahrani A, Arango Sancho P, Bacchetta J, Crowley R, Emma F, Gibbins J, Grandone A, Javaid MK, Mindler G, Raimann A, Rothenbuhler A, Tucker I, Zeitlin L, Linglart A. XLH Matters 2022: Insights and recommendations to improve outcomes for people living with X-linked hypophosphataemia (XLH). Orphanet J Rare Dis 2023; 18:333. [PMID: 37885021 PMCID: PMC10604503 DOI: 10.1186/s13023-023-02883-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023] Open
Affiliation(s)
- Lothar Seefried
- Orthopedic Institute, König-Ludwig Haus, University of Würzburg, Würzburg, Germany
| | - Ali Alzahrani
- King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Pedro Arango Sancho
- Department of Pediatric Nephrology, Hospital Sant Joan de Déu, Barcelona, Spain
- Department of Onco-Nephrology, Pediatric Cancer Center, Barcelona, Spain
| | - Justine Bacchetta
- Pediatric Nephrology, Reference Center for Rare Diseases of Calcium and Phosphate, Filières OSCAR et ORKID, INSERM1033, Hospices Civils de Lyon, Lyon, France
| | - Rachel Crowley
- St Vincent's University Hospital and Rare Disease Clinical Trial Network, University College Dublin, Dublin, Ireland
| | - Francesco Emma
- Division of Nephrology, Children's Hospital Bambino Gesù-IRCCS, Rome, Italy
| | | | - Anna Grandone
- Department of Woman, Child, General and Specialized Surgery, University of Campania L. Vanvitelli, Naples, Italy
| | - Muhammad Kassim Javaid
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Gabriel Mindler
- Department of Pediatric Orthopaedics, Orthopaedic Hospital Speising, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | | | - Anya Rothenbuhler
- APHP, Endocrinology and Diabetology for Children, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Filière OSCAR, Paris, France
- APHP, Platform of Expertise for Rare Disorders Paris Saclay, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France
| | - Ian Tucker
- Bristol Royal Hospital for Children, University Hospitals Bristol and Weston NHS Foundation Trust, Bristol, UK
| | - Leonid Zeitlin
- Pediatric Bone Clinic, Orthopedic Department, Dana-Dwek Children's Hospital, Tel-Aviv Medical Center, Tel Aviv-Yafo, Israel
| | - Agnès Linglart
- APHP, Endocrinology and Diabetology for Children, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France.
- APHP, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Filière OSCAR, Paris, France.
- APHP, Platform of Expertise for Rare Disorders Paris Saclay, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France.
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16
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Kocijan R, Mindler GT, Hartmann MA, Kraus DA, Raimann A, Zwerina J. Dissociation of clinical, laboratory, and bone biopsy findings in adult X-linked hypophosphatemia: a case report. Wien Med Wochenschr 2023; 173:339-345. [PMID: 36695943 DOI: 10.1007/s10354-022-01000-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/15/2022] [Indexed: 01/26/2023]
Abstract
X‑linked hypophosphatemia (XLH) is a phosphate wasting disorder. Typical serum constellations include low serum phosphate as well as high alkaline phosphatase (ALP) and fibroblast growth factor 23 (FGF-23 ) levels. Adult XLH patients usually suffer from (pseudo)fractures, enthesopathies, impaired mobility, and osteoarthritis. We report the case of a middle-aged woman with clinically mild disease, relatively balanced laboratory values, but bone non-healing of the femur post-surgery. Transiliac bone biopsy revealed pronounced osteomalacia and severe deterioration of bone microstructure. Due to the lack of XLH-typical symptoms, the patient was not substituted with calcitriol and phosphate in adulthood. Thus, laboratory findings and radiological examinations do not necessarily reflect bone metabolism in XLH. Bone biopsies should be considered in unclear cases or prior to surgery in adults with XLH.
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Affiliation(s)
- Roland Kocijan
- 1st Medical Department Hanusch Hospital, Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA; Trauma Centre Meidling, Heinrich-Collin-Straße 30, 1140, Vienna, Austria.
- Vienna Bone and Growth Center, Vienna, Austria.
- School of medicine, Metabolic bone diseases unit, Sigmund Freud University Vienna, Vienna, Austria.
| | - Gabriel Tilmann Mindler
- Vienna Bone and Growth Center, Vienna, Austria
- Department of Pediatric Orthopaedics, Orthopaedic Hospital Speising, Vienna, Austria
| | - Markus Alexander Hartmann
- 1st Medical Department Hanusch Hospital, Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA; Trauma Centre Meidling, Heinrich-Collin-Straße 30, 1140, Vienna, Austria
| | - Danial Arian Kraus
- 1st Medical Department Hanusch Hospital, Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA; Trauma Centre Meidling, Heinrich-Collin-Straße 30, 1140, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Adalbert Raimann
- Vienna Bone and Growth Center, Vienna, Austria
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Pulmonology, Allergology and Endocrinology, Medical University Vienna, Vienna, Austria
| | - Jochen Zwerina
- 1st Medical Department Hanusch Hospital, Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA; Trauma Centre Meidling, Heinrich-Collin-Straße 30, 1140, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
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Ewert A, Rehberg M, Schlingmann KP, Hiort O, John-Kroegel U, Metzing O, Wühl E, Schaefer F, Kemper MJ, Derichs U, Richter-Unruh A, Patzer L, Albers N, Dunstheimer D, Haberland H, Heger S, Schröder C, Jorch N, Schmid E, Staude H, Weitz M, Freiberg C, Leifheit-Nestler M, Zivicnjak M, Schnabel D, Haffner D. Effects of Burosumab Treatment on Mineral Metabolism in Children and Adolescents With X-linked Hypophosphatemia. J Clin Endocrinol Metab 2023; 108:e998-e1006. [PMID: 37097907 DOI: 10.1210/clinem/dgad223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/05/2023] [Accepted: 04/13/2023] [Indexed: 04/26/2023]
Abstract
CONTEXT Burosumab has been approved for the treatment of children and adults with X-linked hypophosphatemia (XLH). Real-world data and evidence for its efficacy in adolescents are lacking. OBJECTIVE To assess the effects of 12 months of burosumab treatment on mineral metabolism in children (aged <12 years) and adolescents (aged 12-18 years) with XLH. DESIGN Prospective national registry. SETTING Hospital clinics. PATIENTS A total of 93 patients with XLH (65 children, 28 adolescents). MAIN OUTCOME MEASURES Z scores for serum phosphate, alkaline phosphatase (ALP), and renal tubular reabsorption of phosphate per glomerular filtration rate (TmP/GFR) at 12 months. RESULTS At baseline, patients showed hypophosphatemia (-4.4 SD), reduced TmP/GFR (-6.5 SD), and elevated ALP (2.7 SD, each P < .001 vs healthy children) irrespective of age, suggesting active rickets despite prior therapy with oral phosphate and active vitamin D in 88% of patients. Burosumab treatment resulted in comparable increases in serum phosphate and TmP/GFR in children and adolescents with XLH and a steady decline in serum ALP (each P < .001 vs baseline). At 12 months, serum phosphate, TmP/GFR, and ALP levels were within the age-related normal range in approximately 42%, 27%, and 80% of patients in both groups, respectively, with a lower, weight-based final burosumab dose in adolescents compared with children (0.72 vs 1.06 mg/kg, P < .01). CONCLUSIONS In this real-world setting, 12 months of burosumab treatment was equally effective in normalizing serum ALP in adolescents and children, despite persistent mild hypophosphatemia in one-half of patients, suggesting that complete normalization of serum phosphate is not mandatory for substantial improvement of rickets in these patients. Adolescents appear to require lower weight-based burosumab dosage than children.
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Affiliation(s)
- Annika Ewert
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover 30625, Germany
| | - Mirko Rehberg
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne 50937, Germany
| | - Karl Peter Schlingmann
- Department of General Pediatrics, Pediatric Nephrology, University Children's Hospital, Münster 48149, Germany
| | - Olaf Hiort
- Division of Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University of Lübeck, Lübeck 23562, Germany
| | | | | | - Elke Wühl
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg 69120, Germany
| | - Franz Schaefer
- Division of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg 69120, Germany
| | - Markus J Kemper
- Asklepios Children's Hospital Hamburg-Heidberg, Hamburg-Heidberg 22417, Germany
| | - Ute Derichs
- University Children's Hospital, Mainz 55131, Germany
| | | | - Ludwig Patzer
- St. Elisabeth and St. Barbara Children's Hospital, Halle/Saale 06110, Germany
| | - Norbert Albers
- Christliches Kinderhospital Osnabrück, Osnabrück 49074, Germany
| | | | - Holger Haberland
- Children's Hospital, Sana Klinikum Lichtenberg, Berlin Lichtenberg 10365, Germany
| | - Sabine Heger
- Kinderkrankenhaus auf der Bult, Hannover 30173, Germany
| | - Carmen Schröder
- University Children's Hospital Greifswald, Greifswald 17475, Germany
| | - Norbert Jorch
- University Children's Hospital, Evangelisches Klinikum Bethel, Bielefeld 33617, Germany
| | - Elmar Schmid
- Clinic for Pediatric Nephrology Hirschaid, Hirschaid 96114, Germany
| | - Hagen Staude
- University Children's Hospital Rostock, Rostock 18057, Germany
| | - Marcus Weitz
- Department of General Pediatrics and Hematology/Oncology, University Children's Hospital, University Hospital Tübingen, Tübingen 72076, Germany
| | - Clemens Freiberg
- Department of Pediatrics and Adolescent Medicine, University Medical Center Göttingen, Göttingen 37075, Germany
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover 30625, Germany
| | - Miroslav Zivicnjak
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover 30625, Germany
| | - Dirk Schnabel
- Center for Chronically Sick Children, Pediatric Endocrinology, University Medicine, Charité, Berlin 13353, Germany
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover 30625, Germany
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18
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Abseyi SN, Şıklar Z. Approach to Rickets: Is It Calciopenic or Phosphopenic? Turk Arch Pediatr 2023; 58:458-466. [PMID: 37427438 PMCID: PMC10543743 DOI: 10.5152/turkarchpediatr.2023.23050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/04/2023] [Indexed: 07/11/2023]
Abstract
Rickets is a childhood disorder of decreased mineralization of bone tissue. It is either calciopenic or phosphopenic, according to the deficient mineral. Calcium, phosphate, and vitamin D metabolism should be known to understand the pathophysiology of rickets. A deficiency of calcium or vitamin D can be caused by several conditions. These conditions lead to defective osteoid mineralization, impaired chondrocyte differentiation, and apoptosis in the growth plate, resulting in clinical and radiological findings of rickets. Rickets developing as a result of vitamin D deficiency is the most frequently encountered form. Vitamin D-dependent rickets classification is made according to genetic abnormalities of enzymes that are involved in vitamin D metabolism. Phosphopenic rickets is divided mainly into 2 categories that are FGF23 related or not. A systemic approach that includes a detailed history, physical examination, and laboratory evaluation is required when performing a diagnostic evaluation. Vitamin D and calcium supplementation should be used to treat nutritional rickets. To prevent rickets and its morbidities, vitamin D prophylaxis in the newborn period is suggested. High dose of vitamin D3, 1.25(OH)2D, and calcium are treatment choices in vitamin D-dependent rickets according to its subgroup. If conventional treatment consisting of phosphate and calcitriol is ineffective in the treatment of phosphopenic rickets, Burosumab is the new treatment option.
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Affiliation(s)
- Sema Nilay Abseyi
- Department of Pediatric Endocrinology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Zeynep Şıklar
- Department of Pediatric Endocrinology, Ankara University Faculty of Medicine, Ankara, Turkey
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19
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Legare JM, Basel D. What the pediatric endocrinologist needs to know about skeletal dysplasia, a primer. Front Pediatr 2023; 11:1229666. [PMID: 37675393 PMCID: PMC10477785 DOI: 10.3389/fped.2023.1229666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/07/2023] [Indexed: 09/08/2023] Open
Abstract
Children with skeletal dysplasia are frequently referred to pediatric endocrinologists due to short stature. These children may present with disproportionate growth or medical histories that point to a skeletal dysplasia. This primer will discuss when to be concerned about skeletal dysplasia, the initial steps in evaluation for a skeletal dysplasia, and new therapies that are either recently approved or in development.
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Affiliation(s)
- Janet M. Legare
- Department of Pediatrics, University of Wisconsin School of Medicineand Public Health, Madison, WI, United States
| | - Donald Basel
- Department of Pediatrics, Medical Collegeof Wisconsin, Milwaukee, WI, United States
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20
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Arboleya L, Braña I, Pardo E, Loredo M, Queiro R. Osteomalacia in Adults: A Practical Insight for Clinicians. J Clin Med 2023; 12:jcm12072714. [PMID: 37048797 PMCID: PMC10094844 DOI: 10.3390/jcm12072714] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/26/2023] [Accepted: 04/01/2023] [Indexed: 04/14/2023] Open
Abstract
The term osteomalacia (OM) refers to a series of processes characterized by altered mineralization of the skeleton, which can be caused by various disorders of mineral metabolism. OM can be genetically determined or occur due to acquired disorders, among which the nutritional origin is particularly relevant, due to its wide epidemiological extension and its nature as a preventable disease. Among the hereditary diseases associated with OM, the most relevant is X-linked hypophosphatemia (XLH), which manifests in childhood, although its consequences persist into adulthood where it can acquire specific clinical characteristics, and, although rare, there are XLH cases that reach the third or fourth decade of life without a diagnosis. Some forms of OM present very subtle initial manifestations which cause both considerable diagnosis and treatment delay. On occasions, the presence of osteopenia and fragility fractures leads to an erroneous diagnosis of osteoporosis, which may imply the prescription of antiresorptive drugs (i.e., bisphosphonates or denosumab) with catastrophic consequences for OM bone. On the other hand, some radiological features of OM can be confused with those of axial spondyloarthritis and lead to erroneous diagnoses. The current prevalence of OM is not known and is very likely that its incidence is much higher than previously thought. Moreover, OM explains part of the therapeutic failures that occur in patients diagnosed with other bone diseases. Therefore, it is essential that clinicians who treat adult skeletal diseases take into account the considerations provided in this practical review when focusing on the diagnosis and treatment of their patients with bone diseases.
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Affiliation(s)
- Luis Arboleya
- Rheumatology Division, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain
| | - Ignacio Braña
- Rheumatology Division, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain
| | - Estefanía Pardo
- Rheumatology Division, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain
| | - Marta Loredo
- Rheumatology Division, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain
| | - Rubén Queiro
- Rheumatology Division, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain
- ISPA Translational Immunology Division, Biohealth Research Institute of the Principality of Asturias (ISPA), 33011 Oviedo, Spain
- School of Medicine, Oviedo University, 33011 Oviedo, Spain
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21
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Pons-Belda OD, Alonso-Álvarez MA, González-Rodríguez JD, Mantecón-Fernández L, Santos-Rodríguez F. Mineral Metabolism in Children: Interrelation between Vitamin D and FGF23. Int J Mol Sci 2023; 24:ijms24076661. [PMID: 37047636 PMCID: PMC10094813 DOI: 10.3390/ijms24076661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 03/29/2023] [Accepted: 04/01/2023] [Indexed: 04/05/2023] Open
Abstract
Fibroblast growth factor 23 (FGF23) was identified at the turn of the century as the long-sought circulating phosphatonin in human pathology. Since then, several clinical and experimental studies have investigated the metabolism of FGF23 and revealed its relevant pathogenic role in various diseases. Most of these studies have been performed in adult individuals. However, the mineral metabolism of the child is, to a large extent, different from that of the adult because, in addition to bone remodeling, the child undergoes a specific process of endochondral ossification responsible for adequate mineralization of long bones’ metaphysis and growth in height. Vitamin D metabolism is known to be deeply involved in these processes. FGF23 might have an influence on bones’ growth as well as on the high and age-dependent serum phosphate concentrations found in infancy and childhood. However, the interaction between FGF23 and vitamin D in children is largely unknown. Thus, this review focuses on the following aspects of FGF23 metabolism in the pediatric age: circulating concentrations’ reference values, as well as those of other major variables involved in mineral homeostasis, and the relationship with vitamin D metabolism in the neonatal period, in vitamin D deficiency, in chronic kidney disease (CKD) and in hypophosphatemic disorders.
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Affiliation(s)
| | | | | | | | - Fernando Santos-Rodríguez
- Hospital Universitario Central de Asturias, 33011 Oviedo, Spain
- Department of Medicine, Faculty of Medicine, University of Oviedo, 33003 Oviedo, Spain
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22
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Portales-Castillo I, Rieg T, Khalid SB, Nigwekar SU, Neyra JA. Physiopathology of Phosphate Disorders. ADVANCES IN KIDNEY DISEASE AND HEALTH 2023; 30:177-188. [PMID: 36868732 PMCID: PMC10565570 DOI: 10.1053/j.akdh.2022.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/24/2022] [Accepted: 12/29/2022] [Indexed: 03/05/2023]
Abstract
Intracellular phosphate is critical for cellular processes such as signaling, nucleic acid synthesis, and membrane function. Extracellular phosphate (Pi) is an important component of the skeleton. Normal levels of serum phosphate are maintained by the coordinated actions of 1,25-dihydroxyvitamin D3, parathyroid hormone and fibroblast growth factor-23, which intersect in the proximal tubule to control the reabsorption of phosphate via the sodium-phosphate cotransporters Npt2a and Npt2c. Furthermore, 1,25-dihydroxyvitamin D3 participates in the regulation of dietary phosphate absorption in the small intestine. Clinical manifestations associated with abnormal serum phosphate levels are common and occur as a result of genetic or acquired conditions affecting phosphate homeostasis. For example, chronic hypophosphatemia leads to osteomalacia in adults and rickets in children. Acute severe hypophosphatemia can affect multiple organs leading to rhabdomyolysis, respiratory dysfunction, and hemolysis. Patients with impaired kidney function, such as those with advanced CKD, have high prevalence of hyperphosphatemia, with approximately two-thirds of patients on chronic hemodialysis in the United States having serum phosphate levels above the recommended goal of 5.5 mg/dL, a cutoff associated with excess risk of cardiovascular complications. Furthermore, patients with advanced kidney disease and hyperphosphatemia (>6.5 mg/dL) have almost one-third excess risk of death than those with phosphate levels between 2.4 and 6.5 mg/dL. Given the complex mechanisms that regulate phosphate levels, the interventions to treat the various diseases associated with hypophosphatemia or hyperphosphatemia rely on the understanding of the underlying pathobiological mechanisms governing each patient condition.
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Affiliation(s)
- Ignacio Portales-Castillo
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, MA; Endocrine Unit, Massachusetts General Hospital, and Harvard Medical School, Boston, MA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL; James A. Haley Veterans' Hospital, Tampa, FL; Center for Hypertension and Kidney Research, University of South Florida, Tampa, FL
| | - Sheikh B Khalid
- Department of Internal Medicine, The Indus Hospital, Lahore Pakistan
| | - Sagar U Nigwekar
- Division of Nephrology, Department of Medicine, Massachusetts General Hospital, and Harvard Medical School, Boston, MA
| | - Javier A Neyra
- Department of Internal Medicine, Division of Nephrology, University of Alabama at Birmingham, Birmingham, AL.
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23
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Root AW, Levine MA. One half-century of advances in the evaluation and management of disorders of bone and mineral metabolism in children and adolescents. J Pediatr Endocrinol Metab 2023; 36:105-118. [PMID: 36636022 PMCID: PMC10406614 DOI: 10.1515/jpem-2022-0624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 01/14/2023]
Abstract
The past 50 years of research in pediatric bone and mineral metabolism have led to remarkable progress in the identification and characterization of disorders that affect the developing skeleton. Progress has been facilitated through advances in both technology and biology and this paper provides a brief description of some but not all of the key findings, including identification of the calcium sensing receptor and the polypeptides parathyroid hormone and parathyroid hormone-related protein as well as their shared receptor and signal generating pathways; the elucidation of vitamin D metabolism and actions; discovery of fibroblast growth factor 23 (FGF23), the sodium-phosphate co-transporters and the other components that regulate phosphate metabolism. Moreover, the past half-century of research has led to the delineation of the molecular bases for genetic forms of hypoparathyroidism, pseudohypoparathyroidism, and primary hyperparathyroidism as well as the determination of the genetic causes of osteogenesis imperfecta, osteopetrosis, hypophosphatasia, and other disorders of mineral/bone homeostasis. During the next decade we expect that many of these fundamental discoveries will lead to the development of innovative treatments that will improve the lives of children with these disorders.
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Affiliation(s)
- Allen W. Root
- Johns Hopkins All Children’s Hospital, St. Petersburg, FL, USA
| | - Michael A. Levine
- Corresponding author: Michael A. Levine, MD, The Center for Bone Health at the Children’s Hospital of Philadelphia, Philadelphia, PA, USA,
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24
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Walker EYX, Lindsay TAJ, Allgrove J, Marlais M, Bockenhauer D, Hayes W. Burosumab in management of X-linked hypophosphataemia: a retrospective cohort study of growth and serum phosphate levels. Arch Dis Child 2023; 108:379-384. [PMID: 36717209 DOI: 10.1136/archdischild-2022-324962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 01/09/2023] [Indexed: 02/01/2023]
Abstract
BACKGROUND Burosumab, an antifibroblast growth factor 23 monoclonal antibody, improves rickets severity, symptoms and growth in children with X-linked hypophosphataemia (XLH) followed up to 64 weeks in clinical trials. International dosing guidance recommends targeting normal serum phosphate concentration; however, some children may not achieve this despite maximal dosing. This study compares clinical outcomes in children with XLH on long-term burosumab treatment who achieved normal phosphate versus those who did not. METHODS Single-centre retrospective review of a large paediatric cohort with XLH treated with burosumab. We evaluated growth and biochemical markers of bone health in those who did compared with those who did not achieve normal plasma phosphate concentration. RESULTS Fifty-five children with XLH with median age of 11.7 (IQR 6.8-15.5) years were included. 27 (49%) had low plasma phosphate concentration, and 27 (49%) had normal phosphate after a median burosumab treatment duration of 3.3 (IQR 2.6-3.7) years. 1 (2%) did not have a recent phosphate level recorded. No difference in growth was found between normal and abnormal phosphate groups (p=0.9). CONCLUSIONS Young children with XLH experience sustained growth on long-term burosumab treatment, although without normal plasma phosphate concentration in many. Consideration should be made to changing burosumab dosing recommendations to target normalisation of alkaline phosphatase, as opposed to plasma phosphate concentration.
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Affiliation(s)
- Emma Yi Xiu Walker
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | | | - Jeremy Allgrove
- Department of Endocrinology, Great Ormond Street Hospital For Children NHS Foundation Trust, London, UK
| | - Matko Marlais
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.,Institute of Child Health, University College London, London, UK
| | - Detlef Bockenhauer
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.,Department of Renal Medicine, University College London, London, UK
| | - Wesley Hayes
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK .,Institute of Child Health, University College London, London, UK
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Weber TJ, Imel EA, Carpenter TO, Peacock M, Portale AA, Hetzer J, Merritt JL, Insogna K. Long-term Burosumab Administration Is Safe and Effective in Adults With X-linked Hypophosphatemia. J Clin Endocrinol Metab 2022; 108:155-165. [PMID: 36072994 PMCID: PMC9759172 DOI: 10.1210/clinem/dgac518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 08/24/2022] [Indexed: 02/03/2023]
Abstract
CONTEXT Burosumab was developed as a treatment option for patients with the rare, lifelong, chronically debilitating, genetic bone disease X-linked hypophosphatemia (XLH). OBJECTIVE Collect additional information on the safety, immunogenicity, and clinical response to long-term administration of burosumab. METHODS UX023-CL203 (NCT02312687) was a Phase 2b, open-label, single-arm, long-term extension study of adult subjects with XLH who participated in KRN23-INT-001 or KRN23-INT-002 studies. The long-term UX023-CL203 study (January 5, 2015 through November 30, 2018) provided data up to 184 weeks. Participants in UX023-CL203 received burosumab based on the last dose in the prior KRN23-INT-001 or KRN23-INT-002 studies (0.3, 0.6, or 1.0 mg/kg given by subcutaneous injection every 4 weeks). At Week 12, burosumab could be titrated upward/downward to achieve fasting serum phosphate levels within the normal range. Primary objectives included long-term safety, the proportion of subjects achieving fasting serum phosphate in the normal range, changes in bone turnover markers, patient-reported outcomes for pain and stiffness, and measures of mobility. RESULTS Fasting serum phosphate levels at the midpoint of the dosing interval (2 weeks postdose, the time of peak effect) were within the normal range in 85% to 100% of subjects. Measures of phosphate metabolism and bone biomarkers generally improved with burosumab therapy, approaching or reaching their respective normal ranges by study end. Improvements in patient-reported outcomes and mobility were sustained throughout the observation period. No new safety findings emerged with longer-term burosumab treatment. CONCLUSION These data support the conclusion that burosumab therapy may be a safe and effective long-term treatment option for adult patients with XLH.
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Affiliation(s)
- Thomas J Weber
- Correspondence: Thomas J. Weber, MD, Division of Endocrinology, Metabolism and Nutrition, 303 Baker House, DUMC 3470, Duke University Medical Center, Durham, NC 27710, USA.
| | - Erik A Imel
- Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | | | - Munro Peacock
- Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | | | - Joel Hetzer
- Ultragenyx Pharmaceutical Inc., Novato, CA 94949, USA
| | | | - Karl Insogna
- Yale University School of Medicine, New Haven, CT 06520, USA
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Huynh C, Gillis A, Fazendin J, Abdullatif H. A case report to assess the safety and efficacy of Burosumab, an investigational antibody to FGF23, in a single pediatric patient with Epidermal Nevus Syndrome and associated hypophosphatemic rickets. Bone Rep 2022; 17:101605. [PMID: 35899095 PMCID: PMC9309659 DOI: 10.1016/j.bonr.2022.101605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/12/2022] [Accepted: 07/15/2022] [Indexed: 11/20/2022] Open
Abstract
Epidermal Nevus Syndrome (ENS), also known as Cutaneous Skeletal Hypophosphatemia Syndrome or Linear Sebaceous Nevus Syndrome, is caused by a mosaic somatic mutation of RAS (Rat Sarcoma genes) which leads to abnormally elevated levels of fibroblast growth factor 23 (FGF23). FGF23 is a major regulator in phosphate homeostasis. There are multiple disorders, along with Epidermal Nevus Syndrome (ENS), that result in unusually high circulating levels of FGF23. This increase ultimately leads to renal phosphate wasting and reduced levels of 1,25-dihydroxy vitamin D. Across these disorders, the clinical symptoms are similar and often include osteomalacia (hypophosphatemic rickets in children), muscle weakness, fatigue, joint deformities, bone pain, and fractures. Burosumab (KRN23), is an IgG1 monoclonal antibody that binds to the FGF23 receptor and inhibits the activity of FGF23. This leads to an increase in serum phosphate levels. Burosumab emerged as a potential therapy in FGF23 overactivity disorders. Burosumab was successful in the treatment of X-linked hypophosphatemia (XLH) and is now FDA-approved for its treatment. Studies have indicated that Burosumab therapy in subjects with XLH consistently increases and sustains serum phosphorus levels and tubular reabsorption of phosphate without a major impact on urine calcium levels or vitamin D metabolism. We studied the effect of Burosumab treatment in a single pediatric patient with Epidermal Nevus Syndrome. Serum phosphorus rose gradually as we titrated the dose of Burosumab upwards. During treatment, a persistent elevation of parathyroid hormone levels was noted along with a persistent elevation of serum calcium. We presumed the patient had tertiary hyperparathyroidism. However, after the removal of three parathyroid glands, the pathology came back with a single enlarged parathyroid adenoma. Subsequently, his calcium and PTH, and phosphorus levels stabilized while taking only Burosumab. ClinicalTrials.gov NCT04320316. Burosumab was superior to conventional therapy in our subject with ENS. The subject had persistent hyperparathyroidism during treatment. Hyperparathyroidism corrected with removal of parathyroid adenoma
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Affiliation(s)
- Carson Huynh
- Corresponding author at: University of Alabama at Birmingham Department of Pediatrics, United States of America.
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Marques JVO, Moreira CA, Borba VZC. New treatments for rare bone diseases: hypophosphatemic rickets/osteomalacia. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2022; 66:658-665. [PMID: 36382755 PMCID: PMC10118827 DOI: 10.20945/2359-3997000000555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phosphorus is one of the most abundant minerals in the human body; it is required to maintain bone integrity and mineralization, in addition to other biological processes. Phosphorus is regulated by parathyroid hormone, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and fibroblast growth factor 23 (FGF-23) in a complex set of processes that occur in the gut, skeleton, and kidneys. Different molecular mechanisms - overproduction of FGF-23 by tumors responsible for oncogenic osteomalacia, generation of an FGF-23 mutant that is resistant to cleavage by enzymes, and impaired FGF-23 degradation due to a reduction in or loss of the PHEX gene - can lead to FGF-23-stimulating activity and the consequent waste of urinary phosphate and low levels of 1,25(OH)2D3. Conventional treatment consists of multiple daily doses of oral phosphate salts and vitamin D analogs, which may improve radiographic rickets but do not normalize growth. Complications of the conventional long-term treatment consist of hypercalcemia, hypercalciuria, nephrolithiasis, nephrocalcinosis, impaired renal function, and potentially chronic kidney disease. Recently, burosumab, an antibody against FGF-23, was approved as a novel therapy for children and adults with X-linked hypophosphatemia and patients with tumor-induced osteomalacia. Burosumab showed good performance in different trials in children and adults. It increased and sustained the serum phosphorus levels, decreased the rickets severity and pain scores, and improved mineralization. It offers a new perspective on the treatment of chronic and disabling diseases.
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Newey PJ, Hannan FM, Wilson A, Thakker RV. Genetics of monogenic disorders of calcium and bone metabolism. Clin Endocrinol (Oxf) 2022; 97:483-501. [PMID: 34935164 PMCID: PMC7614875 DOI: 10.1111/cen.14644] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/24/2021] [Accepted: 11/07/2021] [Indexed: 12/19/2022]
Abstract
Disorders of calcium homeostasis are the most frequent metabolic bone and mineral disease encountered by endocrinologists. These disorders usually manifest as primary hyperparathyroidism (PHPT) or hypoparathyroidism (HP), which have a monogenic aetiology in 5%-10% of cases, and may occur as an isolated endocrinopathy, or as part of a complex syndrome. The recognition and diagnosis of these disorders is important to facilitate the most appropriate management of the patient, with regard to both the calcium-related phenotype and any associated clinical features, and also to allow the identification of other family members who may be at risk of disease. Genetic testing forms an important tool in the investigation of PHPT and HP patients and is usually reserved for those deemed to be an increased risk of a monogenic disorder. However, identifying those suitable for testing requires a thorough clinical evaluation of the patient, as well as an understanding of the diversity of relevant phenotypes and their genetic basis. This review aims to provide an overview of the genetic basis of monogenic metabolic bone and mineral disorders, primarily focusing on those associated with abnormal calcium homeostasis, and aims to provide a practical guide to the implementation of genetic testing in the clinic.
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Affiliation(s)
- Paul J Newey
- Division of Molecular and Clinical Medicine, Ninewells Hospital & Medical School, University of Dundee, Scotland, UK
| | - Fadil M Hannan
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, UK
| | - Abbie Wilson
- Division of Molecular and Clinical Medicine, Ninewells Hospital & Medical School, University of Dundee, Scotland, UK
| | - Rajesh V Thakker
- Academic Endocrine Unit, Oxford Centre for Diabetes, Endocrinology & Metabolism (OCDEM), Churchill Hospital, University of Oxford, Oxford, UK
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Fratzl-Zelman N, Hartmann MA, Gamsjaeger S, Rokidi S, Paschalis EP, Blouin S, Zwerina J. Bone Matrix Mineralization and Response to Burosumab in Adult Patients With X-Linked Hypophosphatemia: Results From the Phase 3, Single-Arm International Trial. J Bone Miner Res 2022; 37:1665-1678. [PMID: 35775373 DOI: 10.1002/jbmr.4641] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/20/2022] [Accepted: 06/25/2022] [Indexed: 11/06/2022]
Abstract
X-linked hypophosphatemia (XLH) is characterized by excess fibroblast growth factor 23 (FGF23) secretion, renal phosphate wasting, and low 1,25(OH)2 D3 . Adult patients present with osteomalacia, hypomineralized periosteocytic lesions, bone fragility, and pain. Burosumab is a fully human monoclonal FGF23 antibody approved for XLH treatment. UX023-CL304 was an open-label, phase 3 study investigating the effects of burosumab on osteomalacia in adults with XLH, who remained untreated at least 2 years prior enrollment. Here, we present the effect of burosumab on bone material properties. We analyzed transiliac bone biopsy samples from 11 individuals before and after 48 weeks of subcutaneous burosumab treatment (1.0 mg/kg administered every 4 weeks). We used quantitative backscattered electron imaging (qBEI) and Fourier transform infrared imaging (FTIRI) to assess bone mineralization density distribution (BMDD), mineralized bone volume, properties of the organic matrix, and size of periosteocytic lesions. The outcomes were compared with reference values from healthy adults and with four XLH patients either untreated or treated by conventional therapy. Prior to burosumab, the average mineralization in cancellous bone was lower than in healthy reference. CaLow, the fraction of lowly mineralized matrix, and CaHigh, the fraction of highly mineralized matrix, were both elevated resulting in a broad heterogeneity in mineralization (CaWidth). Burosumab resulted in a decrease of CaHigh toward normal range, whereas CaLow and CaWidth remained elevated. The mineralized bone volume was notably increased (+35.9%). The size of the periosteocytic lesions was variable but lower than in untreated XLH patients. FTIRI indicated decreased enzymatic collagen crosslink ratio heterogeneity. In summary, matrix mineralization in XLH is very heterogeneous. Highly mineralized regions represent old bone packets, probably protected from osteoclastic resorption by osteoid seams. The concomitant decrease of highly mineralized matrix, persistence of lowly mineralized matrix, and increase in mineralized bone volume after burosumab suggest a boost in mineralization of preexisting unmineralized or very lowly mineralized matrix, providing a potential explanation for previously observed improved osteomalacia. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Nadja Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Markus A Hartmann
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Sonja Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria
| | - Stamatia Rokidi
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria
| | - Eleftherios P Paschalis
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Stéphane Blouin
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Jochen Zwerina
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
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30
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Treatment of X-Linked Hypophosphatemia in Children. ENDOCRINES 2022. [DOI: 10.3390/endocrines3030042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The conventional treatment for X-linked hypophosphatemia (XLH), consisting of phosphorus supplementation and a biologically active form of vitamin D (alfacalcidol or calcitriol), is used to treat rickets and leg deformities and promote growth. However, patients’ adult height often remains less than −2 SD. Moreover, adverse events, such as renal calcification and hyperparathyroidism, may occur. The main pathology in XLH is caused by excessive production of fibroblast growth factor 23 (FGF23). Several studies have demonstrated that treatment with burosumab, a blocking neutralizing antibody against FGF23, is better than conventional therapy for severe XLH and has no serious, short-term side effects. Thus, treatment with burosumab may be an option for severe XLH. The present article reviews the conventional and burosumab therapies. In addition to the fact that the long-term efficacy of antibody-based treatment has not been demonstrated, there are other, unresolved issues concerning the burosumab treatment of XLH.
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31
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The regulation of FGF23 under physiological and pathophysiological conditions. Pflugers Arch 2022; 474:281-292. [PMID: 35084563 PMCID: PMC8837506 DOI: 10.1007/s00424-022-02668-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 12/18/2022]
Abstract
Fibroblast growth factor 23 (FGF23) is an important bone hormone that regulates phosphate homeostasis in the kidney along with active vitamin D (1,25(OH)2D3) and parathyroid hormone (PTH). Endocrine effects of FGF23 depend, at least in part, on αKlotho functioning as a co-receptor whereas further paracrine effects in other tissues are αKlotho-independent. Regulation of FGF23 production is complex under both, physiological and pathophysiological conditions. Physiological regulators of FGF23 include, but are not limited to, 1,25(OH)2D3, PTH, dietary phosphorus intake, and further intracellular and extracellular factors, kinases, cytokines, and hormones. Moreover, several acute and chronic diseases including chronic kidney disease (CKD) or further cardiovascular disorders are characterized by early rises in the plasma FGF23 level pointing to further mechanisms effective in the regulation of FGF23 under pathophysiological conditions. Therefore, FGF23 also serves as a prognostic marker in several diseases. Our review aims to comprehensively summarize the regulation of FGF23 in health and disease.
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Haffner D, Leifheit-Nestler M, Grund A, Schnabel D. Rickets guidance: part II-management. Pediatr Nephrol 2022; 37:2289-2302. [PMID: 35352187 PMCID: PMC9395459 DOI: 10.1007/s00467-022-05505-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 02/08/2022] [Accepted: 02/09/2022] [Indexed: 11/28/2022]
Abstract
Here, we discuss the management of different forms of rickets, including new therapeutic approaches based on recent guidelines. Management includes close monitoring of growth, the degree of leg bowing, bone pain, serum phosphate, calcium, alkaline phosphatase as a surrogate marker of osteoblast activity and thus degree of rickets, parathyroid hormone, 25-hydroxyvitamin D3, and calciuria. An adequate calcium intake and normal 25-hydroxyvitamin D3 levels should be assured in all patients. Children with calcipenic rickets require the supplementation or pharmacological treatment with native or active vitamin D depending on the underlying pathophysiology. Treatment of phosphopenic rickets depends on the underlying pathophysiology. Fibroblast-growth factor 23 (FGF23)-associated hypophosphatemic rickets was historically treated with frequent doses of oral phosphate salts in combination with active vitamin D, whereas tumor-induced osteomalacia (TIO) should primarily undergo tumor resection, if possible. Burosumab, a fully humanized FGF23-antibody, was recently approved for treatment of X-linked hypophosphatemia (XLH) and TIO and shown to be superior for treatment of XLH compared to conventional treatment. Forms of hypophosphatemic rickets independent of FGF23 due to genetic defects of renal tubular phosphate reabsorption are treated with oral phosphate only, since they are associated with excessive 1,25-dihydroxyvitamin D production. Finally, forms of hypophosphatemic rickets caused by Fanconi syndrome, such as nephropathic cystinosis and Dent disease require disease-specific treatment in addition to phosphate supplements and active vitamin D. Adjustment of medication should be done with consideration of treatment-associated side effects, including diarrhea, gastrointestinal discomfort, hypercalciuria, secondary hyperparathyroidism, and development of nephrocalcinosis or nephrolithiasis.
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Affiliation(s)
- Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. .,Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany ,Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Andrea Grund
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany ,Pediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Dirk Schnabel
- Center for Chronically Sick Children, Pediatric Endocrinology, Charitè, University Medicine, Berlin, Germany
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33
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Mughal MZ, Baroncelli GI, de Lucas-Collantes C, Linglart A, Magnolato A, Raimann A, Santos F, Schnabel D, Shaw N, Nilsson O. Burosumab for X-linked hypophosphatemia in children and adolescents: Opinion based on early experience in seven European countries. Front Endocrinol (Lausanne) 2022; 13:1034580. [PMID: 36798486 PMCID: PMC9928183 DOI: 10.3389/fendo.2022.1034580] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/11/2022] [Indexed: 02/03/2023] Open
Abstract
Given the relatively recent introduction of burosumab in the management of X-linked hypophosphatemia (XLH), there is limited real-world data to guide its use in clinical practice. As a group of European physicians experienced with burosumab treatment in clinical practice, we convened with the objective of sharing these practice-based insights on the use of burosumab in children and adolescents with XLH. We attended two virtual meetings, then discussed key questions via Within3, a virtual online platform. Points of discussion related to patient selection criteria, burosumab starting dose, dose titration and treatment monitoring. Our discussions revealed that criteria for selecting children with XLH varied across Europe from all children above 1 year to only children with overt rickets despite conventional treatment being eligible. We initiated burosumab dosing according to guidance in the Summary of Product Characteristics, an international consensus statement from 2019 and local country guidelines. Dose titration was primarily guided by serum phosphate levels, with some centers also using the ratio of tubular maximum reabsorption of phosphate to glomerular filtration rate (TmP/GFR). We monitored response to burosumab treatment clinically (growth, deformities, bone pain and physical functioning), radiologically (rickets and deformities) and biochemically (serum phosphate, alkaline phosphatase, 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D, urine calcium-creatinine ratio and TmP/GFR). Key suggestions made by our group were initiation of burosumab treatment in children as early as possible, from the age of 1 year, particularly in those with profound rickets, and a need for clinical studies on continuation of burosumab throughout adolescence and into adulthood.
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Affiliation(s)
- M. Zulf Mughal
- Department of Paediatric Endocrinology and Metabolic Bone Diseases, Royal Manchester Children’s Hospital, Manchester, United Kingdom
- The Faculty of Biology, Medicine, and Health, University of Manchester, Manchester, United Kingdom
- *Correspondence: M. Zulf Mughal,
| | - Giampiero I. Baroncelli
- Division of Pediatrics, Endocrine Unit, ERN-BOND Representative, Department of Obstetrics, Gynecology and Pediatrics, University-Hospital, Pisa, Italy
| | - Carmen de Lucas-Collantes
- Servicio Nefrología, Hospital Infantil Universitario Niño Jesús, Universidad Autónoma de Madrid, Madrid, Spain
| | - Agnès Linglart
- AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, Filière OSCAR, Bicêtre Paris Saclay Hospital, Paris, France
- Platform of Expertise for Rare Disorders, INSERM, Physiologie et Physiopathologie Endocriniennes, Paris Saclay University, Paris, France
| | - Andrea Magnolato
- Department of Pediatrics, Institute for Maternal and Child Health – IRCCS “Burlo Garofolo”, Trieste, Italy
| | - Adalbert Raimann
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Pulmonology, Allergology and Endocrinology, Medical University of Vienna, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Fernando Santos
- Hospital Universitario Central de Asturias (HUCA), University of Oviedo, Oviedo, Spain
| | - Dirk Schnabel
- Center for Chronic Sick Children, Pediatric Endocrinology, Charitè, University Medicine, Berlin, Germany
| | - Nick Shaw
- Department of Endocrinology and Diabetes, Birmingham Women’s and Children’s NHS Foundation Trust, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, United Kingdom
| | - Ola Nilsson
- Division of Pediatric Endocrinology, Department of Women’s and Children’s Health , Karolinska Institutet and University Hospital, Stockholm, Sweden
- School of Medical Sciences, Department of Pediatrics, Örebro University and University Hospital, Örebro, Sweden
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34
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Mindler GT, Stauffer A, Kranzl A, Penzkofer S, Ganger R, Radler C, Haeusler G, Raimann A. Persistent Lower Limb Deformities Despite Amelioration of Rickets in X-Linked Hypophosphatemia (XLH) - A Prospective Observational Study. Front Endocrinol (Lausanne) 2022; 13:866170. [PMID: 35399930 PMCID: PMC8987359 DOI: 10.3389/fendo.2022.866170] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 02/22/2022] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Gait deviations, lower limb pain and joint stiffness represent key symptoms in patients with X-linked hypophosphatemia (XLH, OMIM 307800), a rare disorder of mineral homeostasis. While the pathomechanism for rickets is well understood, the direct role of PHEX (Phosphate-regulating neutral endopeptidase) deficiency in non-rachitic features including complex deformities, skull and dental affections remains unclear. FGF23-inhibiting antibody treatment can normalize serum phosphate levels and to improve rickets in XLH patients. However, linear growth remains impaired and effects on lower limb deformity and gait are insufficiently studied. AIMS To characterize and evaluate the course of lower limb deformity in a case series of pediatric XLH patients receiving Burosumab therapy. METHODS Comparative assessment of planar radiographs, gait analysis, biochemical and clinical features of pediatric patients before and ≥12 months after initiation of FGF23-inhibiting was performed prospectively. Lower limb maltorsion was quantified by torsional MRI and gait analysis. Standardized deformity analysis of lower limb anteroposterior radiographs was conducted. RESULTS Seven patients (age 9.0 +/-3.6 years) were eligible for this study. All patients received conventional treatment before onset of antibody treatment. Maltorsion of the femur was observed in 8/14 legs using torsional MRI (mean antetorsion 8.79°). Maltorsion of the tibia was observed in 9/14 legs (mean external torsion 2.8°). Gait analysis confirmed MRI findings with femoral external malrotation prior to and one year after onset of Burosumab therapy. Internal foot progression (intoeing gait) remained pathological in all cases (mean 2.2°). Knee rotation was pathologically internal 10/14 legs. Mean mechanical axis deviation (MAD) of 16.1mm prior to Burosumab changed in average by 3.9mm. Three children underwent guided growth procedures within the observation period. Mild postprocedural rebound of frontal axis deviation was observed under Burosumab treatment in one patient. CONCLUSIONS This is the first study to investigate lower limb deformity parameters quantitatively in children with XLH receiving Burosumab. One year of Burosumab therapy was associated with persistent maltorsion and frontal axis deviation (varus/valgus) despite improved rickets in this small, prospective uncontrolled study.
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Affiliation(s)
- Gabriel T. Mindler
- Department of Pediatric Orthopaedics, Orthopaedic Hospital Speising, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Alexandra Stauffer
- Department of Pediatric Orthopaedics, Orthopaedic Hospital Speising, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Andreas Kranzl
- Vienna Bone and Growth Center, Vienna, Austria
- Laboratory for Gait and Movement Analysis, Orthopaedic Hospital Speising, Vienna, Austria
| | - Stefan Penzkofer
- MRI Institute Bader, Orthopaedic Hospital Speising, Vienna, Austria
| | - Rudolf Ganger
- Department of Pediatric Orthopaedics, Orthopaedic Hospital Speising, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Christof Radler
- Department of Pediatric Orthopaedics, Orthopaedic Hospital Speising, Vienna, Austria
- Vienna Bone and Growth Center, Vienna, Austria
| | - Gabriele Haeusler
- Vienna Bone and Growth Center, Vienna, Austria
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Pulmonology, Allergology and Endocrinology, Medical University of Vienna, Vienna, Austria
| | - Adalbert Raimann
- Vienna Bone and Growth Center, Vienna, Austria
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Pulmonology, Allergology and Endocrinology, Medical University of Vienna, Vienna, Austria
- *Correspondence: Adalbert Raimann,
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