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Salles Rosa Neto N, Pereira RMR, Yuki EFN, Souza FHCD, Takayama L, Carneiro MIDS, Lima LGCAD, Ishy A, Elias AJR. Healing of tumor-induced osteomalacia as assessed by high-resolution peripheral quantitative computed tomography is not similar across the skeleton in the first years following complete tumor excision. Bone Rep 2024; 21:101758. [PMID: 38584681 PMCID: PMC10997823 DOI: 10.1016/j.bonr.2024.101758] [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: 11/23/2023] [Revised: 03/24/2024] [Accepted: 03/27/2024] [Indexed: 04/09/2024] Open
Abstract
Tumor-induced osteomalacia is caused by excessive fibroblast growth factor 23 production mainly from phosphaturic mesenchymal tumors. Surgical excision or tumor ablation are the preferred treatment. Information on bone microarchitecture parameters assessed by high-resolution peripheral quantitative computed tomography is limited. We report a woman with hypophosphatemic osteomalacia with generalized pain, weakness and recurrent fractures, and a large thoracic vertebral mass extending to the posterior mediastinum. Detailed radiologic and histopathologic evaluation revealed a phosphaturic mesenchymal tumor. Two surgeries were necessary for complete removal of the mass. Clinical symptoms improved after attaining normophosphatemia. Four-year post-surgical HR-pQCT parameters, compared to baseline, showed in the left distal radius, stable trabecular and cortical volumetric bone mineral density although below reference range. There was stability of trabecular number and thickness. Both stiffness and failure load decreased. A shift in cortical parameters was noted in year 2. In the left distal tibia, trabecular volumetric bone mineral density decreased whereas cortical volumetric bone mineral density markedly increased, as did cortical area. There was stability in the trabecular number and thickness. Both stiffness and failure load improved. Findings from HR-pQCT measurements in this patient disclosed that the healing of osteomalacia is not similar across the peripheral skeletal sites in the first years following tumor removal. Results contrasted low but stable volumetric bone mineral density in the distal radius with increase in the distal tibia at the expense of cortical bone. Our report helps further delineate the pattern of bone healing after treatment of this rare bone disorder.
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Affiliation(s)
- Nilton Salles Rosa Neto
- Center for Rare and Immune Disorders, Hospital Nove de Julho, São Paulo, Brazil
- Universidade Santo Amaro, São Paulo, Brazil
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Liu S, Zhou X, Liu Y, Zhang J, Xia W. Preoperative evaluation and orthopedic surgical strategies for tumor-induced osteomalacia. J Bone Oncol 2024; 45:100600. [PMID: 38577550 PMCID: PMC10990903 DOI: 10.1016/j.jbo.2024.100600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 03/24/2024] [Accepted: 03/27/2024] [Indexed: 04/06/2024] Open
Abstract
Tumor-induced osteomalacia (TIO), also known as oncogenic osteomalacia, is very rare, with about 1000 reported cases globally. Removing most TIO culprit tumors requires the evaluation and intervention of orthopedic doctors. However, orthopedic doctors often have a poor understanding of the optical treatment of TIO due to its rarity. In addition, most TIO patients lack specific clinical manifestations. Also, the clinical localization and qualitative diagnosis of TIO are difficult and thus can easily be misdiagnosed and mistreated. Furthermore, the true incidence rate of TIO may be underestimated. Although many breakthroughs have been made in exploring the pathogenesis, clinical diagnosis, and treatment of TIO, rational and standardized orthopedic surgical treatment experience summary and sorting for TIO patients are lacking. In this article, the recent experience and progress in the field of orthopedic surgical treatment for TIO globally have been summarized, providing a theoretical basis and new clinical practice guidance for the rational treatment of TIO patients.
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Affiliation(s)
- Shuzhong Liu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Xi Zhou
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Yong Liu
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Jianguo Zhang
- Department of Orthopaedic Surgery, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Weibo Xia
- Department of Endocrinology, National Health Commission Key Laboratory of Endocrinology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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Cancarevic I, Ilyas U, Nassar M. Hypophosphatemia in Patients With Multiple Myeloma. Cureus 2023; 15:e40487. [PMID: 37342302 PMCID: PMC10279409 DOI: 10.7759/cureus.40487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2023] [Indexed: 06/22/2023] Open
Abstract
Hypophosphatemia is among the most common electrolyte abnormalities, especially among patients with underlying malignancies, and is frequently associated with adverse prognoses. Phosphorus levels are regulated through a number of mechanisms, including parathyroid hormone (PTH), fibroblast growth factor-23 (FGF-23), vitamin D, and other electrolyte levels themselves. Clinically, the findings are nonspecific, and the diagnosis is frequently delayed. This article is a narrative literature review. The PubMed database was searched for relevant articles pertaining to hypophosphatemia causes and consequences in patients suffering from multiple myeloma. We found a variety of causes of hypophosphatemia in patients with multiple myeloma. Tumor-induced osteopenia, although more common among patients with small squamous cell carcinomas, can occur with multiple myeloma as well. Additionally, both light chains themselves and medications can trigger Fanconi syndrome, which leads to phosphorus wasting by the kidney. Bisphosphonates, in addition to being a possible cause of Fanconi syndrome, lead to a decrease in calcium levels, which then stimulates parathyroid hormone (PTH) release, predisposing the patient to significant hypophosphatemia. Additionally, many of the more modern medications used to manage multiple myeloma have been associated with hypophosphatemia. A better understanding of those mechanisms may give clinicians a clearer idea of which patients may need more frequent screening as well as what the potential triggers in the individual patient may be.
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Affiliation(s)
- Ivan Cancarevic
- Internal Medicine, Icahn School of Medicine at Mount Sinai, Queens Hospital Center, New York, USA
| | - Usman Ilyas
- Internal Medicine, Icahn School of Medicine at Mount Sinai, Queens Hospital Center, New York, USA
| | - Mahmoud Nassar
- Internal Medicine, Icahn School of Medicine at Mount Sinai, NYC Health + Hospitals/Queens, New York, USA
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Ni X, Guan W, Jiang Y, Li X, Chi Y, Pang Q, Liu W, Jiajue R, Wang O, Li M, Xing X, Wu H, Huo L, Liu Y, Jin J, Zhou X, Lv W, Zhou L, Xia Y, Gong Y, Yu W, Xia W. High prevalence of vertebral deformity in tumor-induced osteomalacia associated with impaired bone microstructure. J Endocrinol Invest 2023; 46:487-500. [PMID: 36097315 DOI: 10.1007/s40618-022-01918-z] [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: 08/06/2022] [Accepted: 09/02/2022] [Indexed: 10/14/2022]
Abstract
PURPOSE Patients with tumor-induced osteomalacia (TIO) often suffer from irreversible height loss due to vertebral deformity. However, the prevalence of vertebral deformity in TIO patients varies among limited studies. In addition, the distribution and type of vertebral deformity, as well as its risk factors, remain unknown. This study aimed to identify the prevalence, distribution, type and risk factors for vertebral deformity in a large cohort of TIO patients. METHODS A total of 164 TIO patients were enrolled in this retrospective study. Deformity in vertebrae T4-L4 by lateral thoracolumbar spine radiographs was evaluated according to the semiquantitative method of Genant. Bone microstructure was evaluated by trabecular bone score (TBS) and high-resolution peripheral QCT (HR-pQCT). RESULTS Ninety-nine (99/164, 60.4%) patients had 517 deformed vertebrae with a bimodal pattern of distribution (T7-9 and T11-L1), and biconcave deformity was the most common type (267/517, 51.6%). Compared with patients without vertebral deformity, those with vertebral deformity had a higher male/female ratio, longer disease duration, more height loss, lower serum phosphate, higher bone turnover markers, lower TBS, lower areal bone mineral density (aBMD), lower peripheral volumetric BMD (vBMD) and worse microstructure. Lower trabecular vBMD and worse trabecular microstructure in the peripheral bone and lower spine TBS were associated with an increased risk of vertebral deformity independently of aBMD. After adjusting for the number of deformed vertebrae, we found little difference in clinical indexes among the patients with different types of vertebral deformity. However, we found significant correlations of clinical indexes with the number of deformed vertebrae and the spinal deformity index. CONCLUSION We reported a high prevalence of vertebral deformity in the largest cohort of TIO patients and described the vertebral deformity in detail for the first time. Risk factors for vertebral deformity included male sex, long disease duration, height loss, abnormal biochemical indexes and bone impairment. Clinical manifestation, biochemical indexes and bone impairment were correlated with the number of deformed vertebrae and degree of deformity, but not the type of deformity.
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Affiliation(s)
- X Ni
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - W Guan
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Y Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - X Li
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - Y Chi
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - Q Pang
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - W Liu
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - R Jiajue
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - O Wang
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - M Li
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - X Xing
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China
| | - H Wu
- Department of Pathology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - L Huo
- Department of Nuclear Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Y Liu
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - J Jin
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - X Zhou
- Department of Orthopedic Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - W Lv
- Department of Ear, Nose, and Throat, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - L Zhou
- Department of Stomatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Y Xia
- Department of Ultrasound Diagnosis, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Y Gong
- Medical Research Center, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - W Yu
- Department of Radiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China.
| | - W Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, National Commission of Health, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Shuaifuyuan No. 1, Wangfujing Street, Dongcheng District, Beijing, 100730, China.
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Jan de Beur SM, Minisola S, Xia WB, Abrahamsen B, Body JJ, Brandi ML, Clifton-Bligh R, Collins M, Florenzano P, Houillier P, Imanishi Y, Imel EA, Khan AA, Zillikens MC, Fukumoto S. Global guidance for the recognition, diagnosis, and management of tumor-induced osteomalacia. J Intern Med 2023; 293:309-328. [PMID: 36511653 PMCID: PMC10108006 DOI: 10.1111/joim.13593] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by mesenchymal tumors that secrete fibroblast growth factor 23 (FGF23). Patients present with progressive bone pain, muscle weakness, and fragility fractures. TIO is characterized by hypophosphatemia, excess renal phosphate excretion, and low/inappropriately normal 1,25-dihydroxyvitamin D (1,25(OH)2 D) levels. Rarity and enigmatic clinical presentation of TIO contribute to limited awareness among the medical community. Accordingly, appropriate diagnostic tests may not be requested, leading to delayed diagnosis and poorer patient outcomes. We have developed a global guidance document to improve the knowledge of TIO in the medical community, enabling the recognition of patients with TIO and appropriate referral. We provide recommendations aiding diagnosis, referral, and treatment, helping promote a global standard of patient management. We reviewed the literature and conducted a three-round Delphi survey of TIO experts. Statements were drafted based on published evidence and expert opinions (≥70% consensus required for final recommendations). Serum phosphate should be measured in patients presenting with chronic muscle pain or weakness, fragility fractures, or bone pain. Physical examination should establish features of myopathy and identify masses that could be causative tumors. Priority laboratory evaluations should include urine/serum phosphate and creatinine to assess renal tubular reabsorption of phosphate and TmP/GFR, alkaline phosphatase, parathyroid hormone, 25-hydroxyvitamin D, 1,25(OH)2 D, and FGF23. Patients with the clinical/biochemical suspicion of TIO should be referred to a specialist for diagnosis confirmation, and functional imaging should be used to localize causative tumor(s). Recommended treatment is tumor resection or, with unresectable/unidentifiable tumors, phosphate salts plus active vitamin D, or burosumab.
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Affiliation(s)
- Suzanne M Jan de Beur
- Division of Endocrinology and Metabolism, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Salvatore Minisola
- Department of Clinical, Internal, Anesthesiology and Cardiovascular Sciences, Sapienza University, Rome, Italy
| | - Wei-Bo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, State Key Laboratory of Complex Severe and Rare Diseases, NHC, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Bo Abrahamsen
- Open Patient data Explorative Network (OPEN), Department of Clinical Research, University of Southern Denmark and Odense University Hospital, Odense, Denmark.,Department of Medicine, Holbaek Hospital, Holbaek, Denmark.,Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Jean-Jacques Body
- Department of Medicine, CHU Brugmann, Université Libre de Bruxelles, Brussels, Belgium
| | - Maria Luisa Brandi
- Department of Surgery and Translational Medicine, University of Florence, University Hospital of Florence, Florence, Italy
| | - Roderick Clifton-Bligh
- Department of Endocrinology and Diabetes, Royal North Shore Hospital, Sydney, Australia.,Cancer Genetics Unit, Kolling Institute, Sydney, Australia.,Sydney Medical School, University of Sydney, Sydney, Australia
| | - Michael Collins
- Skeletal Diseases and Mineral Homeostasis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - Pablo Florenzano
- Centro Traslacional de Endocrinología UC (CETREN-UC), Endocrinology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pascal Houillier
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Département des Maladies Rénales et Métaboliques, Hôpital Européen Georges-Pompidou, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Yasuo Imanishi
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan
| | - Erik A Imel
- Division of Endocrinology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Aliya A Khan
- Division of Endocrinology and Metabolism, Calcium Disorders Clinic, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - M Carola Zillikens
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Seiji Fukumoto
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
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Crotti C, Zucchi F, Alfieri C, Caporali R, Varenna M. Reply to: appropriate dosing of burosumab in tumor-induced osteomalacia. Osteoporos Int 2023; 34:423-424. [PMID: 36454247 DOI: 10.1007/s00198-022-06618-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 11/18/2022] [Indexed: 12/04/2022]
Affiliation(s)
- C Crotti
- Department of Rheumatology, ASST-Pini-CTO, Milan, Italy
| | - F Zucchi
- Department of Rheumatology, ASST-Pini-CTO, Milan, Italy
| | - C Alfieri
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
- Department of Nephrology, Dialysis and Renal Transplant, Foundation Ca' Granda IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - R Caporali
- Department of Rheumatology, ASST-Pini-CTO, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - M Varenna
- Department of Rheumatology, ASST-Pini-CTO, Milan, Italy.
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7
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Crotti C, Zucchi F, Alfieri C, Caporali R, Varenna M. Long-term use of burosumab for the treatment of tumor-induced osteomalacia. Osteoporos Int 2023; 34:201-206. [PMID: 35925260 PMCID: PMC9361946 DOI: 10.1007/s00198-022-06516-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/22/2022] [Indexed: 01/07/2023]
Abstract
UNLABELLED Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by tumoral overproduction of FGF-23. Due to local recurrence, we describe the long-term efficacy and safety profile of burosumab, an anti-FGF-23 monoclonal antibody, in a TIO patient after three unsuccessfully surgical attempts. INTRODUCTION TIO is a rare paraneoplastic syndrome caused by tumoral overproduction of fibroblast growth factor 23 (FGF23), resulting in hyperphospaturia, hypophosphatemia, and osteomalacia. Surgery is the only definitive treatment, but tumor can locally recur, even after years from primary surgery. Furthermore, some tumors cannot be removed by surgery due to their location. METHODS We describe the case of a 54-year-old woman affected by recurrent TIO who, after three unsuccessful surgical attempts of tumor removal, was treated with burosumab, an anti-FGF-23 monoclonal antibody. RESULTS The patient was referred to our Bone Unit after experiencing several fractures in different sites, both traumatic and non-traumatic. At the time of first evaluation, at the age of 46, serum-phosphate (SP) was 1.2 mg/dL (reference range (RR) 2.5-4.5), 24-h urinary phosphate was 842 mg (RR 400-1000), and intact-FGF-23 was 117 pg/mL (RR 25-45). Imaging showed a metabolic pre-sacral lesion that firstly underwent to exploratory laparotomy. Then, patient underwent to surgical excision of tumor. After 18 months of well-being, tumor relapsed and even the subsequent surgery was not able to completely remove it. Since 2015, patient was maintained in phosphorus supplements and 1,25(OH)2vitamin D3, but SP levels never normalized. In September 2019, she was started on burosumab, initially at the dose of 0.3 mg/kg/month, progressively increased to the current 0.8 mg/kg/month, with great improvement of pain, physical performance, and normalization of SP levels. Burosumab was temporary and cautionary discontinued for COVID-19 pneumonia, with a worsening of SP. After restart of burosumab, biochemistry returned to normal. CONCLUSIONS To our knowledge, this is the first European patient affected by TIO treated with burosumab for more than 2 years. Burosumab is a promising therapy in the medical treatment of TIO refractory or not eligible for definitive surgery, with good efficacy and safety profile.
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Affiliation(s)
- C Crotti
- Department of Rheumatology, ASST-Pini-CTO, Milan, Italy
| | - F Zucchi
- Department of Rheumatology, ASST-Pini-CTO, Milan, Italy
| | - C Alfieri
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
- Department of Nephrology, Dialysis and Renal Transplant, Foundation Ca' Granda IRCCS Ospedale Maggiore Policlinico, Milan, Italy
| | - R Caporali
- Department of Rheumatology, ASST-Pini-CTO, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - M Varenna
- Department of Rheumatology, ASST-Pini-CTO, Milan, Italy.
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8
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Kritmetapak K, Kumar R. Phosphatonins: From Discovery to Therapeutics. Endocr Pract 2023; 29:69-79. [PMID: 36210014 DOI: 10.1016/j.eprac.2022.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/22/2022] [Accepted: 09/23/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Phosphate is crucial for cell signaling, energy metabolism, nucleotide synthesis, and bone mineralization. The gut-bone-parathyroid-kidney axis is influenced by parathyroid hormone, 1,25-dihydroxyvitamin D, and phosphatonins, especially fibroblast growth factor 23 (FGF23). These hormones facilitate maintenance of phosphate homeostasis. This review summarizes current knowledge regarding the phosphate homeostasis, phosphatonin pathophysiology, and clinical implications of FGF23-related hypophosphatemic disorders, with specific focus on burosumab treatment. METHOD A focused literature search of PubMed was conducted. RESULTS Phosphatonins including FGF23, secreted frizzled-related protein 4, matrix extracellular phosphoglycoprotein, and fibroblast growth factor 7 play a pathogenic role in several hypophosphatemic disorders. Excess FGF23 inhibits sodium-dependent phosphate cotransporters (NaPi-2a and NaPi-2c), resulting in hyperphosphaturia and hypophosphatemia. Additionally, FGF23 suppresses 1,25-dihydroxyvitamin D synthesis in the proximal renal tubule, and thus, it indirectly inhibits intestinal phosphate absorption. Disorders of FGF23-related hypophosphatemia include X-linked hypophosphatemia (XLH), autosomal dominant hypophosphatemic rickets, autosomal recessive hypophosphatemic rickets, fibrous dysplasia/McCune-Albright syndrome, and tumor-induced osteomalacia (TIO). Complications of conventional therapy with oral phosphate and vitamin D analogs comprise gastrointestinal distress, hypercalcemia, nephrocalcinosis, and secondary/tertiary hyperparathyroidism. In both children and adults with XLH and TIO, the anti-FGF23 antibody burosumab exhibits a favorable safety profile and is associated with healing of rickets in affected children and improvement of osteomalacia in both children and adults. CONCLUSION The treatment paradigm for XLH and TIO is changing based on data from recent clinical trials. Research suggest that burosumab is effective and safe for pediatric and adult patients with XLH or TIO.
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Affiliation(s)
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota.
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9
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Roumpou A, Yavropoulou MP, Chronopoulos E, Kassi E. Novel Therapeutic Agents for Rare Diseases of Calcium and Phosphate Metabolism. Horm Metab Res 2022; 54:645-657. [PMID: 36049757 DOI: 10.1055/a-1917-0519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The last decade has been revolutionary regarding the management of rare bone diseases caused by impaired calcium and phosphate metabolism. Elucidation of the underlying genetic basis and pathophysiologic alterations has been the determinant factor for the development of new, disease-specific treatment agents. The phosphaturic hormone Fibroblast Growth Factor 23 (FGF23) possesses a critical role in the pathogenesis of various hypophosphatemic disorders. Among them, the genetic disorder of X-linked hypophosphatemia and the acquired syndrome of tumor-induced osteomalacia, although very rare, have attracted the scientific community's attention towards designing an FGF23-inhibitor as a potential specific therapy. The monoclonal antibody burosumab was approved for the treatment of children and adult patients with X-linked hypophosphatemia and recently for tumor-induced osteomalacia patients, demonstrating benefits regarding their symptoms, biochemical profile and bone mineralization status. Asfotase alfa is a hydroxyapatite-targeted recombinant alkaline phosphatase, an enzymatic replacement therapy, substituting the defective activity of tissue non-specific alkaline phosphatase, in patients suffering from hypophosphatasia. Promising data regarding its favorable effect on survival rate, bone quality, fracture healing, muscle strength, mobility, respiratory function, and general quality of life have led to the approval of the drug for the treatment of childhood-onset hypophosphatasia. Given the high costs of treatment for both agents and their limited clinical use until now, more data are needed to define patients' characteristics that make them ideal candidates for therapy. Long-term safety issues also need to be clarified.
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Affiliation(s)
- Afroditi Roumpou
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, "Aghia Sofia" Children's Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
- Laboratory for Research of the Musculoskeletal System, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
| | - Maria P Yavropoulou
- Centre of Expertise for Rare Endocrine Diseases, C.E.R.E.D. Disorders of Calcium & Phosphate Metabolism, First Department of Propaedeutic and Internal Medicine, Laiko Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
| | - Efstathios Chronopoulos
- Laboratory for Research of the Musculoskeletal System, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
| | - Eva Kassi
- Laboratory for Research of the Musculoskeletal System, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
- Centre of Expertise for Rare Endocrine Diseases, C.E.R.E.D. Disorders of Calcium & Phosphate Metabolism, First Department of Propaedeutic and Internal Medicine, Laiko Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece
- Department of Biological Chemistry, National and Kapodistrian University of Athens, Athens, Greece
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