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Leifheit-Nestler M, Haffner D. How FGF23 shapes multiple organs in chronic kidney disease. Mol Cell Pediatr 2021; 8:12. [PMID: 34536161 PMCID: PMC8449753 DOI: 10.1186/s40348-021-00123-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/07/2021] [Indexed: 12/13/2022] Open
Abstract
Chronic kidney disease (CKD) is associated with distinct alterations in mineral metabolism in children and adults resulting in multiple organ dysfunctions. Children with advanced CKD often suffer from impaired bone mineralization, bone deformities and fractures, growth failure, muscle weakness, and vascular and soft tissue calcification, a complex which was recently termed CKD-mineral and bone disorder (CKD-MBD). The latter is a major contributor to the enhanced cardiovascular disease comorbidity and mortality in these patients. Elevated circulating levels of the endocrine-acting phosphaturic hormone fibroblast growth factor (FGF) 23 are the first detectable alteration of mineral metabolism and thus CKD-MBD. FGF23 is expressed and secreted from osteocytes and osteoblasts and rises, most likely due to increased phosphate load, progressively as kidney function declines in order to maintain phosphate homeostasis. Although not measured in clinical routine yet, CKD-mediated increased circulating levels of FGF23 in children are associated with pathological cardiac remodeling, vascular alterations, and increased cognitive risk. Clinical and experimental studies addressing other FGF23-mediated complications of kidney failure, such as hypertension and impaired bone mineralization, show partly conflicting results, and the causal relationships are not always entirely clear. This short review summarizes regulators of FGF23 synthesis altered in CKD and the main CKD-mediated organ dysfunctions related to high FGF23 levels.
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Affiliation(s)
- Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
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2
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Bacchetta J, Rothenbuhler A, Gueorguieva I, Kamenicky P, Salles JP, Briot K, Linglart A. X-linked hypophosphatemia and burosumab: Practical clinical points from the French experience. Joint Bone Spine 2021; 88:105208. [PMID: 34102329 DOI: 10.1016/j.jbspin.2021.105208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/14/2021] [Indexed: 10/21/2022]
Abstract
Hereditary hypophosphatemia with increased FGF23 levels are rare inherited metabolic diseases characterized by low serum phosphate because of impaired renal tubular phosphate reabsorption. The most common form is X-linked hypophosphatemia (XLH), secondary to a mutation in the PHEX gene. In children, XLH is often manifested by rickets, delayed development of gait, lower limb deformities, growth retardation, craniosynostosis, and spontaneous dental abscesses. In adults, patients present diffuse musculoskeletal pain (bone and joints), early osteoarthritis, entesopathies, pseudo-fractures, muscular weakness, and severe dental damage. Conventional medical management is based on the combined administration of oral phosphate supplementation with active vitamin D analogs. Treatment with the recently approved anti-FGF23 burosumab is an alternative, especially in severe forms. Burosumab restores phosphate reabsorption in the proximal tubule and stimulates the endogenous synthesis of calcitriol. In Europe, burosumab has been approved for the treatment of XLH with radiographic evidence of bone disease in pediatric patients from one year of age and in adults. This manuscript will discuss the specific management of burosumab in children and adolescents in daily practice.
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Affiliation(s)
- Justine Bacchetta
- Reference Center for Rare Renal Diseases, Department of Pediatric Nephrology, Rheumatology and Dermatology, Nephrogones, Filière ORKiD, HFME, Lyon University Hospital, Lyon, France; Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, Filière OSCAR, HFME, Lyon University Hospital, Lyon, France
| | - Anya Rothenbuhler
- AP-HP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France; AP-HP, Endocrinology and Diabetes for Children, Bicêtre Paris-Sud Hospital, Le Kremlin-Bicêtre, France
| | - Iva Gueorguieva
- Pediatric Department, Endocrinology Unit, Children's Center, Lille University Hospital, Jeanne-de-Flandre Hospital, Lille, France
| | - Peter Kamenicky
- AP-HP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France; AP-HP, Department of Endocrinology and Reproductive Diseases, Bicêtre Paris-Sud Hospital, Paris, France
| | - Jean-Pierre Salles
- Unit of Endocrinology, Bone Diseases, Genetics and Gynecology, Children's Hospital, Toulouse University Hospital, 31059 Toulouse cedex 09, France; Toulouse-Purpan Pathophysiology Center, CPTP, INSERM UMR 1043, Paul-Sabatier University, Toulouse, France
| | - Karine Briot
- AP-HP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France; AP-HP, Department of Rheumatology, Cochin Hospital, Paris, France
| | - Agnès Linglart
- AP-HP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France; AP-HP, Endocrinology and Diabetes for Children, Bicêtre Paris-Sud Hospital, Le Kremlin-Bicêtre, France.
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3
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Constantacos C, Hunter JD, Walsh ET, South AM. Rare PHEX variant with insidious presentation leads to a delayed diagnosis of X-linked hypophosphatemia. BMJ Case Rep 2021; 14:14/5/e240336. [PMID: 34011663 DOI: 10.1136/bcr-2020-240336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
A 7-year-old girl without a significant previous medical history was diagnosed with X-linked hypophosphatemic rickets (XLHR) due to a rare, most likely pathogenic, PHEX gene variant after a 4-year delayed diagnosis due to mild clinical presentation. At 2 years of age, her intoeing and femoral bowing were attributed to physiologic bowing and borderline vitamin D sufficiency, despite phosphorus not being measured. Hypophosphatemia was eventually detected after incomplete improvement of bowing and leg length discrepancy with suboptimal linear growth. This rare PHEX variant (c.1949T>C, p.Leu650Pro) further supported the clinical diagnosis of XLHR. Treatment with burosumab (an anti-FGF23 monoclonal antibody) normalised phosphorus and alkaline phosphatase levels and improved her bowing. The diverse phenotypic presentation of this variant can result in delayed diagnosis and highlights the importance of prompt assessment of phosphorus levels in patients with skeletal deformities to ensure timely recognition and treatment.
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Affiliation(s)
- Cathrine Constantacos
- Pediatrics, Section of Endocrinology, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA
| | - Janel Darcy Hunter
- Pediatrics, Section of Endocrinology, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA
| | - Elizabeth Tharpe Walsh
- Pediatrics, Section of Endocrinology, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA
| | - Andrew Michael South
- Pediatrics, Section of Nephrology, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA.,Epidemiology and Prevention, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA
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Arango Sancho P. Complications of Phosphate and Vitamin D Treatment in X-Linked Hypophosphataemia. Adv Ther 2020; 37:105-112. [PMID: 32236871 DOI: 10.1007/s12325-019-01170-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Indexed: 01/01/2023]
Abstract
Conventional treatment of X-linked hypophosphataemia (XLH) consists in the oral administration of phosphate plus calcitriol supplements. Although this therapy has reduced bone deformities and even achieved adequate patient growth, overtreatment or low adherence could lead to subsequent consequences that may compromise the efficacy of the therapy. Some of the complications associated with phosphate and vitamin D treatment are abdominal discomfort, diarrhoea, hypokalaemia, hyperparathyroidism, hypercalcaemia or hypercalciuria, nephrocalcinosis or nephrolithiasis, and ectopic calcifications. Therefore, constant multidisciplinary monitoring of patients with XLH is necessary to prevent the manifestation of these complications and to deal with them as soon as they appear. The main objective of this article is to review the main complications arising from conventional treatment of XLH and how to deal with them.
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Affiliation(s)
- Pedro Arango Sancho
- Servicio de Nefrología Pediátrica y Trasplante Renal, Hospital Sant Joan de Déu, Barcelona, Spain.
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5
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Haffner D, Emma F, Eastwood DM, Duplan MB, Bacchetta J, Schnabel D, Wicart P, Bockenhauer D, Santos F, Levtchenko E, Harvengt P, Kirchhoff M, Di Rocco F, Chaussain C, Brandi ML, Savendahl L, Briot K, Kamenicky P, Rejnmark L, Linglart A. Clinical practice recommendations for the diagnosis and management of X-linked hypophosphataemia. Nat Rev Nephrol 2020; 15:435-455. [PMID: 31068690 PMCID: PMC7136170 DOI: 10.1038/s41581-019-0152-5] [Citation(s) in RCA: 252] [Impact Index Per Article: 63.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
X-linked hypophosphataemia (XLH) is the most common cause of inherited phosphate wasting and is associated with severe complications such as rickets, lower limb deformities, pain, poor mineralization of the teeth and disproportionate short stature in children as well as hyperparathyroidism, osteomalacia, enthesopathies, osteoarthritis and pseudofractures in adults. The characteristics and severity of XLH vary between patients. Because of its rarity, the diagnosis and specific treatment of XLH are frequently delayed, which has a detrimental effect on patient outcomes. In this Evidence-Based Guideline, we recommend that the diagnosis of XLH is based on signs of rickets and/or osteomalacia in association with hypophosphataemia and renal phosphate wasting in the absence of vitamin D or calcium deficiency. Whenever possible, the diagnosis should be confirmed by molecular genetic analysis or measurement of levels of fibroblast growth factor 23 (FGF23) before treatment. Owing to the multisystemic nature of the disease, patients should be seen regularly by multidisciplinary teams organized by a metabolic bone disease expert. In this article, we summarize the current evidence and provide recommendations on features of the disease, including new treatment modalities, to improve knowledge and provide guidance for diagnosis and multidisciplinary care. In this Evidence-Based Guideline on X-linked hypophosphataemia, the authors identify the criteria for diagnosis of this disease, provide guidance for medical and surgical treatment and explain the challenges of follow-up.
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Affiliation(s)
- Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany. .,Center for Congenital Kidney Diseases, Center for Rare Diseases, Hannover Medical School, Hannover, Germany.
| | - Francesco Emma
- Department of Pediatric Subspecialties, Division of Nephrology, Children's Hospital Bambino Gesù - IRCCS, Rome, Italy
| | - Deborah M Eastwood
- Department of Orthopaedics, Great Ormond St Hospital for Children, Orthopaedics, London, UK.,The Catterall Unit Royal National Orthopaedic Hospital NHS Trust, Stanmore, UK
| | - Martin Biosse Duplan
- Dental School, Université Paris Descartes Sorbonne Paris Cité, Montrouge, France.,APHP, Department of Odontology, Bretonneau Hospital, Paris, France.,APHP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France
| | - Justine Bacchetta
- Department of Pediatric Nephrology, Rheumatology and Dermatology, University Children's Hospital, Lyon, France
| | - Dirk Schnabel
- Center for Chronic Sick Children, Pediatric Endocrinology, Charitè, University Medicine, Berlin, Germany
| | - Philippe Wicart
- APHP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France.,APHP, Department of Pediatric Orthopedic Surgery, Necker - Enfants Malades University Hospital, Paris, France.,Paris Descartes University, Paris, France
| | - Detlef Bockenhauer
- University College London, Centre for Nephrology and Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Fernando Santos
- Hospital Universitario Central de Asturias (HUCA), University of Oviedo, Oviedo, Spain
| | - Elena Levtchenko
- Department of Pediatric Nephrology and Development and Regeneration, University Hospitals Leuven, University of Leuven, Leuven, Belgium
| | - Pol Harvengt
- RVRH-XLH, French Patient Association for XLH, Suresnes, France
| | - Martha Kirchhoff
- Phosphatdiabetes e.V., German Patient Association for XLH, Lippstadt, Germany
| | - Federico Di Rocco
- Pediatric Neurosurgery, Hôpital Femme Mère Enfant, Centre de Référence Craniosténoses, Université de Lyon, Lyon, France
| | - Catherine Chaussain
- Dental School, Université Paris Descartes Sorbonne Paris Cité, Montrouge, France.,APHP, Department of Odontology, Bretonneau Hospital, Paris, France.,APHP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France
| | - Maria Louisa Brandi
- Metabolic Bone Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Florence, Italy
| | - Lars Savendahl
- Pediatric Endocrinology Unit, Karolinska University Hospital, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Karine Briot
- APHP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France.,Paris Descartes University, Paris, France.,APHP, Department of Rheumatology, Cochin Hospital, Paris, France.,INSERM UMR-1153, Paris, France
| | - Peter Kamenicky
- APHP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France.,APHP, Department of Endocrinology and Reproductive Diseases, Bicêtre Paris-Sud Hospital, Paris, France.,INSERM U1185, Bicêtre Paris-Sud, Paris-Sud - Paris Saclay University, Le Kremlin-Bicêtre, France
| | - Lars Rejnmark
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Agnès Linglart
- APHP, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, and Filière OSCAR, Paris, France.,INSERM U1185, Bicêtre Paris-Sud, Paris-Sud - Paris Saclay University, Le Kremlin-Bicêtre, France.,APHP, Platform of Expertise of Paris-Sud for Rare Diseases and Filière OSCAR, Bicêtre Paris-Sud Hospital (HUPS), Le Kremlin-Bicêtre, France.,APHP, Endocrinology and Diabetes for Children, Bicêtre Paris-Sud Hospital, Le Kremlin-Bicêtre, France
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6
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Lecoq AL, Brandi ML, Linglart A, Kamenický P. Management of X-linked hypophosphatemia in adults. Metabolism 2020; 103S:154049. [PMID: 31863781 DOI: 10.1016/j.metabol.2019.154049] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 10/23/2019] [Accepted: 11/25/2019] [Indexed: 11/27/2022]
Abstract
X-linked hypophosphatemia (XLH) is caused by mutations in the PHEX gene which result in Fibroblast Growth Factor-23 (FG-F23) excess and phosphate wasting. Clinically, XLH children present with rickets, bone deformities and short stature. In adulthood, patients may still be symptomatic with bone and joint pain, osteomalacia-related fractures or pseudofractures, precocious osteoarthrosis, enthesopathy, muscle weakness and severe dental anomalies. Besides these musculoskeletal and dental manifestations, adult XLH patients are also prone to secondary and tertiary hyperparathyroidism, cardiovascular and metabolic disorders. Pathophysiology of hyperparathyroidism is only partially understood but FGF23 excess and deficient production of calcitriol likely contributes to its development. Similarly, the pathophysiological mechanisms of potential cardiovascular and metabolic involvements are not clear, but FGF-23 excess may play an essential role. Treatment should be considered in symptomatic patients, patients undergoing orthopedic or dental surgery and women during pregnancy and lactation. Treatment with oral phosphate salts and active vitamin D analogs has incomplete efficacy and potential risks. Burosumab, a recombinant human monoclonal antibody against FGF-23, has proven its efficacy in phase 2 and phase 3 clinical trials in adult patients with XLH, but currently its position as first line or second line treatment differ among the countries.
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Affiliation(s)
- Anne-Lise Lecoq
- AP-HP, Department of Endocrinology and Reproductive Diseases, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, and Platform of Expertise for Rare Disorders, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France
| | - Maria Luisa Brandi
- Department of Surgery and Translational Medicine, University of Florence, University Hospital of Florence, Florence, Italy
| | - Agnès Linglart
- AP-HP, Endocrinology and Diabetes for Children, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, and Platform of Expertise for Rare Disorders, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France; Université Paris-Saclay, INSERM, Physiologie et Physiopathologie Endocriniennes, Le Kremlin-Bicêtre, France
| | - Peter Kamenický
- AP-HP, Department of Endocrinology and Reproductive Diseases, Reference Center for Rare Disorders of Calcium and Phosphate Metabolism, filière OSCAR, and Platform of Expertise for Rare Disorders, Bicêtre Paris Saclay Hospital, Le Kremlin-Bicêtre, France; Université Paris-Saclay, INSERM, Physiologie et Physiopathologie Endocriniennes, Le Kremlin-Bicêtre, France.
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7
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Imel EA, Zhang X, Ruppe MD, Weber TJ, Klausner MA, Ito T, Vergeire M, Humphrey JS, Glorieux FH, Portale AA, Insogna K, Peacock M, Carpenter TO. Prolonged Correction of Serum Phosphorus in Adults With X-Linked Hypophosphatemia Using Monthly Doses of KRN23. J Clin Endocrinol Metab 2015; 100:2565-73. [PMID: 25919461 PMCID: PMC4495171 DOI: 10.1210/jc.2015-1551] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
CONTEXT In X-linked hypophosphatemia (XLH), elevated fibroblast growth factor 23 (FGF23) decreases the renal tubular maximum reabsorption rate of phosphate/glomerular filtration rate (TmP/GFR) and serum inorganic phosphorus (Pi), resulting in rickets and/or osteomalacia. OBJECTIVE The objective was to test the hypothesis that monthly KRN23 (anti-FGF23 antibody) would safely improve serum Pi in adults with XLH. DESIGN Two sequential open-label phase 1/2 studies were done. SETTING Six academic medical centers were used. PARTICIPANTS Twenty-eight adults with XLH participated in a 4-month dose-escalation study (0.05-0.6 mg/kg); 22 entered a 12-month extension study (0.1-1 mg/kg). INTERVENTION KRN23 was injected sc every 28 days. MAIN OUTCOME MEASURE The main outcome measure was the proportion of subjects attaining normal serum Pi and safety. RESULTS At baseline, mean TmP/GFR, serum Pi, and 1,25-dihydroxyvitamin D [1,25(OH)2D] were 1.6 ± 0.4 mg/dL, 1.9 ± 0.3 mg/dL, and 36.6 ± 14.3 pg/mL, respectively. During dose escalation, TmP/GFR, Pi, and 1,25(OH)2D increased, peaking at 7 days for TmP/GFR and Pi and at 3-7 days for 1,25(OH)2D, remaining above (TmP/GFR, Pi) or near [1,25(OH)2D] pre-dose levels at trough. After each of the four escalating doses, peak Pi was between 2.5 and 4.5 mg/dL in 14.8, 37.0, 74.1, and 88.5% of subjects, respectively. During the 12-month extension, peak Pi was in the normal range for 57.9-85.0% of subjects, and ≥25% maintained trough Pi levels within the normal range. Serum Pi did not exceed 4.5 mg/dL in any subject. Although 1,25(OH)2D levels increased transiently, mean serum and urinary calcium remained normal. KRN23 treatment increased biomarkers of skeletal turnover and had a favorable safety profile. CONCLUSIONS Monthly KRN23 significantly increased serum Pi, TmP/GFR, and 1,25(OH)2D in all subjects. KRN23 has potential for effectively treating XLH.
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Affiliation(s)
- Erik A Imel
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Xiaoping Zhang
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Mary D Ruppe
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Thomas J Weber
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Mark A Klausner
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Takahiro Ito
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Maria Vergeire
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Jeffrey S Humphrey
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Francis H Glorieux
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Anthony A Portale
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Karl Insogna
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Munro Peacock
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
| | - Thomas O Carpenter
- Indiana University School of Medicine (E.A.I., M.P.), Indianapolis, Indiana 46202; Kyowa Hakko Kirin Pharma Inc (X.Z., M.A.K., T.I., M.V., J.S.H.), Princeton, New Jersey 08540; Houston Methodist Hospital (M.D.R.), Houston, Texas 77030; Duke University Medical Center (T.J.W.), Durham, North Carolina 27710; Shriners Hospital for Children (F.H.G.), Montreal, Quebec H3G 1A6, Canada; University of California (A.A.P.), San Francisco, California 94143; and Yale Center for X-Linked Hypophosphatemia (K.I., T.O.C.), Yale University School of Medicine, New Haven, Connecticut 06520
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Carpenter TO, Olear EA, Zhang JH, Ellis BK, Simpson CA, Cheng D, Gundberg CM, Insogna KL. Effect of paricalcitol on circulating parathyroid hormone in X-linked hypophosphatemia: a randomized, double-blind, placebo-controlled study. J Clin Endocrinol Metab 2014; 99:3103-11. [PMID: 25029424 PMCID: PMC4154090 DOI: 10.1210/jc.2014-2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
CONTEXT Hyperparathyroidism occurs frequently in X-linked hypophosphatemia (XLH) and may exacerbate phosphaturia, potentially affecting skeletal abnormalities. OBJECTIVE The objective of the study was to suppress elevated PTH levels in XLH patients. DESIGN This was a prospective, randomized, placebo-controlled, double-blind, 1-year trial of paricalcitol, with outcomes measured at entry and 1 year later. SETTING PATIENTS were recruited from the investigators' clinics or referred from throughout the United States. Data were collected in an in-patient hospital research unit. PATIENTS Subjects with a clinical diagnosis of XLH and hyperparathyroidism were offered participation and were eligible if they were 9 years old or older and not pregnant, and their serum calcium level was less than 10.7 mg/dL, their 25-hydroxyvitamin D level was 20 ng/mL or greater, and their creatinine level was 1.5 mg/dL or less. INTERVENTION The intervention for this study was the use of paricalcitol or placebo for 1 year. MAIN OUTCOME MEASURES Determined prior to trial onset was the change in PTH area under the curve. Secondary outcomes included renal phosphate threshold per glomerular filtration rate, serum phosphorus, serum alkaline phosphatase activity, and (99m)Tc-methylenediphosphonate bone scans. RESULTS PTH area under the curve decreased 17% with paricalcitol, differing (P = .007) from the 20% increase with placebo. The renal phosphate threshold per glomerular filtration rate increased 17% with paricalcitol and decreased 21% with placebo (P = .05). Serum phosphorus increased 12% with paricalcitol but did not differ from placebo. Paricalcitol decreased alkaline phosphatase activity in adults by 21% (no change with placebo, P = .04). Bone scans improved in 6 of 17 paricalcitol subjects, whereas no placebo-treated subject improved. Hypercalciuria developed in six paricalcitol subjects and persisted from baseline in one placebo subject. CONCLUSIONS Suppression of PTH may be a useful strategy for skeletal improvement in XLH patients with hyperparathyroidism, and paricalcitol appears to be an effective adjunct to standard therapy in this setting. Although paricalcitol was well tolerated, urinary calcium and serum calcium and creatinine should be monitored closely with its use.
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Affiliation(s)
- Thomas O Carpenter
- Departments of Pediatrics (Endocrinology) (T.O.C., E.A.O., B.K.E.), Internal Medicine (Endocrinology) (C.A.S., K.L.I.), Orthopaedics and Rehabilitation (T.O.C., C.M.G.), and Diagnostic Radiology (Nuclear Medicine) (D.C.), Yale University School of Medicine, New Haven, Connecticut 06520; and the Veterans Administration Cooperative Studies Program Coordinating Center (JHZ), Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516
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Carpenter TO, Imel EA, Ruppe MD, Weber TJ, Klausner MA, Wooddell MM, Kawakami T, Ito T, Zhang X, Humphrey J, Insogna KL, Peacock M. Randomized trial of the anti-FGF23 antibody KRN23 in X-linked hypophosphatemia. J Clin Invest 2014; 124:1587-97. [PMID: 24569459 DOI: 10.1172/jci72829] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 12/17/2013] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND X-linked hypophosphatemia (XLH) is the most common heritable form of rickets and osteomalacia. XLH-associated mutations in phosphate-regulating endopeptidase (PHEX) result in elevated serum FGF23, decreased renal phosphate reabsorption, and low serum concentrations of phosphate (inorganic phosphorus, Pi) and 1,25-dihydroxyvitamin D [1,25(OH)2D]. KRN23 is a human anti-FGF23 antibody developed as a potential treatment for XLH. Here, we have assessed the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of KRN23 following a single i.v. or s.c. dose of KRN23 in adults with XLH. METHODS Thirty-eight XLH patients were randomized to receive a single dose of KRN23 (0.003-0.3 mg/kg i.v. or 0.1-1 mg/kg s.c.) or placebo. PK, PD, immunogenicity, safety, and tolerability were assessed for up to 50 days. RESULTS KRN23 significantly increased the maximum renal tubular threshold for phosphate reabsorption (TmP/GFR), serum Pi, and 1,25(OH)2D compared with that of placebo (P<0.01). The maximum serum Pi concentration occurred later following s.c. dosing (8-15 days) compared with that seen with i.v. dosing (0.5-4 days). The effect duration was dose related and persisted longer in patients who received s.c. administration. Changes from baseline in TmP/GFR, serum Pi, and serum 1,25(OH)2D correlated with serum KRN23 concentrations. The mean t1/2 of KRN23 was 8-12 days after i.v. administration and 13-19 days after s.c. administration. Patients did not exhibit increased nephrocalcinosis or develop hypercalciuria, hypercalcemia, anti-KRN23 antibodies, or elevated serum parathyroid hormone (PTH) or creatinine. CONCLUSION KRN23 increased TmP/GFR, serum Pi, and serum 1,25(OH)2D. The positive effect of KR23 on serum Pi and its favorable safety profile suggest utility for KRN23 in XLH patients. Trial registration. Clinicaltrials.gov NCT00830674. Funding. Kyowa Hakko Kirin Pharma, Inc.
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10
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Sun GEC, Suer O, Carpenter TO, Tan CD, Li-Ng M. Heart failure in hypophosphatemic rickets: complications from high-dose phosphate therapy. Endocr Pract 2013. [PMID: 23186962 DOI: 10.4158/ep12184.cr] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To report a rare case of hypophosphatemic rickets (HR) leading to extensive cardiac complications. METHODS We present the clinical course and autopsy findings of a patient with HR, treated with chronic phosphate-only therapy as a child, who subsequently developed tertiary hyperparathyroidism leading to extensive cardiac calcifications and complications. We also review the literature on the pathophysiology of calcifications from HR. RESULTS A 34-year-old man was diagnosed with HR at 4 years of age after presenting with growth delay and leg bowing. Family history was negative for the disease. He was initiated on high-dose phosphate therapy (2-6 g of elemental phosphorus/day) with sporadic calcitriol use between 4-18 years of age. For 6 years he received phosphate-only therapy. Subsequently, he developed nephrocalcinosis, heart valve calcifications, severe calcific coronary artery disease, heart block, and congestive heart failure. At a young age, he required an aortic valve replacement and a biventricular pacemaker that was subsequently upgraded to an implantable cardioverter defibrillator. Autopsy showed extensive endocardial, myocardial, and coronary artery calcifications. CONCLUSION Cardiac calcification is a known sequela of tertiary hyperparathyroidism when it occurs in patients with renal failure, but it is rarely seen in HR due to high phosphate therapy. Phosphate alone should never be used to treat HR; high doses, even with calcitriol, should be avoided. It is important to be cognizant of high-dose phosphate effects and to consider parathyroidectomy for autonomous function, if needed. This case emphasizes the importance of appropriate therapy, monitoring, and management of patients with HR.
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Affiliation(s)
- Grace E Ching Sun
- Endocrinology and Metabolism Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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Zaidi AN, Ceneviva GD, Phipps LM, Dettorre MD, Mart CR, Thomas NJ. Myocardial calcification caused by secondary hyperparathyroidism due to dietary deficiency of calcium and vitamin D. Pediatr Cardiol 2005; 26:460-3. [PMID: 15690240 DOI: 10.1007/s00246-004-0765-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A 6-year-old girl presented with respiratory distress. Chest radiographs exhibited calcifications in the mediastinum. Further imaging revealed extensive cardiac calcifications on computed tomography of the chest. The laboratory parameters were consistent with findings of secondary hyperparathyroidism. Detailed review of her dietary history revealed a prolonged history of dietary deficiency of calcium and vitamin D. Treatment consisted of adequate daily replacement of calcium and ergocalciferol. On follow-up, her parathyroid hormone level was significantly reduced and substantially reduced cardiac calcifications were seen on echocardiogram. Pediatric cardiologists must be aware of this potentially fatal but treatable disease in children with cardiac calcifications unexplained by other causes.
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Affiliation(s)
- A N Zaidi
- Department of Internal Medicine and Pediatrics, Penn State Children's Hospital, Penn State University College of Medicine, Hershey, PA 17033, USA
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Abstract
Primary hyperparathyroidism (pHPT) is a common endocrine disorder that predominantly affects postmenopausal women. It is mostly caused by solitary tumours within the parathyroid glands. Although the pathophysiology of pHPT is still incompletely understood, recent studies provide new clues on the development and cellular growth of tumours within the parathyroids associated with hypersecretion of parathyroid hormone and hypercalcaemia. The natural course of pHPT is rather benign. Nowadays, it has become an oligo- or asymptomatic disease often only detected by routine blood tests. These facts raise the question whether to perform parathyroidectomy on oligo- and asymptomatic patients with pHPT or whether it is possible to monitor these patients without surgery. The aim of this article is to review the literature as regards (i) the pathophysiological mechanisms that underlie parathyroid neoplasia and (ii) the defective calcium-sensing in patients with pHPT (iii) environmental and/or genetic risk factors that predispose to or promote parathyroid neoplasia, as well as (iv) alternative approaches to treat oligo- and asymptomatic patients with pHPT medically.
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Affiliation(s)
- S Miedlich
- IIIrd Medical Department, University of Leipzig, Germany
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