| 1. |
- Ariceta, Gema, et al.
(författare)
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The International X-Linked Hypophosphatemia (XLH) Registry : first interim analysis of baseline demographic, genetic and clinical data
- 2023
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Ingår i: Orphanet Journal of Rare Diseases. - : BioMed Central (BMC). - 1750-1172. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: X-linked hypophosphatemia (XLH) is a rare, hereditary, progressive, renal phosphate-wasting disorder characterized by a pathological increase in FGF23 concentration and activity. Due to its rarity, diagnosis may be delayed, which can adversely affect outcomes. As a chronic disease resulting in progressive accumulation of musculoskeletal manifestations, it is important to understand the natural history of XLH over the patient's lifetime and the impact of drug treatments and other interventions. This multicentre, international patient registry (International XLH Registry) was established to address the paucity of these data. Here we present the findings of the first interim analysis of the registry.RESULTS: The International XLH Registry was initiated in August 2017 and includes participants of all ages diagnosed with XLH, regardless of their treatment and management. At the database lock for this first interim analysis (29 March 2021), 579 participants had entered the registry before 30 November 2020 and are included in the analysis (360 children [62.2%], 217 adults [37.5%] and 2 whose ages were not recorded [0.3%]; 64.2% were female). Family history data were available for 319/345 (92.5%) children and 145/187 (77.5%) adults; 62.1% had biological parents affected by XLH. Genetic testing data were available for 341 (94.7%) children and 203 (93.5%) adults; 370/546 (67.8%) had genetic test results; 331/370 (89.5%) had a confirmed PHEX mutation. A notably longer time to diagnosis was observed in adults ≥ 50 years of age (mean [median] duration 9.4 [2.0] years) versus all adults (3.7 [0.1] years) and children (1.0 [0.2] years). Participants presented with normal weight, shorter length or height and elevated body mass index (approximately - 2 and + 2 Z-scores, respectively) versus the general population. Clinical histories were collected for 349 participants (239 children and 110 adults). General data trends for prevalence of bone, dental, renal and joint conditions in all participants were aligned with expectations for a typical population of people with XLH.CONCLUSION: The data collected within the International XLH Registry, the largest XLH registry to date, provide substantial information to address the paucity of natural history data, starting with demographic, family history, genetic testing, diagnosis, auxology and baseline data on clinical presentation.
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| 2. |
- Beck-Nielsen, Signe Sparre, et al.
(författare)
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FGF23 and its role in X-linked hypophosphatemia-related morbidity
- 2019
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Ingår i: Orphanet Journal of Rare Diseases. - : BioMed Central (BMC). - 1750-1172. ; 14:1
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: X-linked hypophosphatemia (XLH) is an inherited disease of phosphate metabolism in which inactivating mutations of the Phosphate Regulating Endopeptidase Homolog, X-Linked (PHEX) gene lead to local and systemic effects including impaired growth, rickets, osteomalacia, bone abnormalities, bone pain, spontaneous dental abscesses, hearing difficulties, enthesopathy, osteoarthritis, and muscular dysfunction. Patients with XLH present with elevated levels of fibroblast growth factor 23 (FGF23), which is thought to mediate many of the aforementioned manifestations of the disease. Elevated FGF23 has also been observed in many other diseases of hypophosphatemia, and a range of animal models have been developed to study these diseases, yet the role of FGF23 in the pathophysiology of XLH is incompletely understood.METHODS: The role of FGF23 in the pathophysiology of XLH is here reviewed by describing what is known about phenotypes associated with various PHEX mutations, animal models of XLH, and non-nutritional diseases of hypophosphatemia, and by presenting molecular pathways that have been proposed to contribute to manifestations of XLH.RESULTS: The pathophysiology of XLH is complex, involving a range of molecular pathways that variously contribute to different manifestations of the disease. Hypophosphatemia due to elevated FGF23 is the most obvious contributor, however localised fluctuations in tissue non-specific alkaline phosphatase (TNAP), pyrophosphate, calcitriol and direct effects of FGF23 have been observed to be associated with certain manifestations.CONCLUSIONS: By describing what is known about these pathways, this review highlights key areas for future research that would contribute to the understanding and clinical treatment of non-nutritional diseases of hypophosphatemia, particularly XLH.
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| 3. |
- Brandi, Maria Luisa, et al.
(författare)
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Post-authorisation safety study of burosumab use in paediatric, adolescent and adult patients with X-linked hypophosphataemia : rationale and description
- 2022
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Ingår i: Therapeutic advances in chronic disease. - : Sage Publications. - 2040-6223 .- 2040-6231. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Background: X-linked hypophosphataemia (XLH) is a rare, inherited, phosphate-wasting disorder that elevates fibroblast growth factor 23 (FGF23), causing renal phosphate-wasting and impaired active vitamin D (1,25(OH)2D) synthesis. Disease characteristics include rickets, osteomalacia, odontomalacia, and short stature. Historically, treatment has been oral phosphate and 1,25(OH)2D supplements. However, these treatments do not correct the primary pathogenic mechanism or treat all symptoms and can be associated with adverse effects. Burosumab is a recombinant human immunoglobulin G1 monoclonal antibody against FGF23, approved for treating XLH in several geographical regions, including Europe and Israel. Burosumab restores normal serum phosphate levels, minimising the clinical consequences of XLH. Safety data on long-term treatment with burosumab are lacking owing to the rarity of XLH. This post-authorisation safety study (PASS) aims to evaluate the safety outcomes in patients aged >1 year.Methods: The PASS is a 10-year retrospective and prospective cohort study utilising data from the International XLH Registry (NCT03193476), which includes standard diagnostic and monitoring practice data at participating centres. The PASS aims to evaluate frequency and severity of safety outcomes, frequency and outcomes of pregnancies in female patients, and safety outcomes in patients with mild to moderate kidney disease at baseline, in children, adolescents and adults treated with burosumab for XLH. It is expected that there will be at least 400 patients who will be administered burosumab.Results: Data collection started on 24 April 2019. The expected date of the final study report is 31 December 2028, with two interim reports.Conclusion: This PASS will provide data on the long-term safety of burosumab treatment for XLH patients and describe safety outcomes for patients receiving burosumab contrasted with those patients receiving other XLH treatments, to help inform the future management of XLH patients. The PASS will be the largest real-world safety study of burosumab.Registry identification: The International XLH Registry is registered with clinicaltrials.gov as NCT03193476 (https://clinicaltrials.gov/ct2/show/NCT03193476), and the PASS is registered with the European Union electronic Register of Post-Authorisation Studies as EUPAS32190 (http://www.encepp.eu/encepp/viewResource.htm?id=32191).
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| 4. |
- M. Boot, Annemieke, et al.
(författare)
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Real-world non-interventional post-authorization safety study of long-term use of burosumab in children and adolescents with X-linked hypophosphatemia : first interim analysis
- 2024
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Ingår i: Therapeutic advances in chronic disease. - : Sage Publications. - 2040-6223. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: X-linked hypophosphatemia (XLH) is a rare, progressive disorder characterized by excess fibroblast growth factor 23 (FGF23), causing renal phosphate-wasting and impaired active vitamin D synthesis. Burosumab is a recombinant human monoclonal antibody that inhibits FGF23, restoring patient serum phosphate levels. Safety data on long-term burosumab treatment are currently limited.OBJECTIVES: This post-authorization safety study (PASS) aims to monitor long-term safety outcomes in children and adolescents (1-17 years) treated with burosumab for XLH. This first interim analysis reports the initial PASS safety outcomes.DESIGN: A 10-year retrospective and prospective cohort study. METHODS: This PASS utilizes International XLH Registry (NCT03193476) data, which includes standard diagnostic and monitoring practice data at participating European centers.RESULTS: At data cut-off (13 May 2021), 647 participants were included in the International XLH Registry; 367 were receiving burosumab, of which 67 provided consent to be included in the PASS. Mean (SD) follow-up time was 2.2 (1.0) years. Mean (SD) age was 7.3 (4.3) years (range 1.0-17.5 years). Mean duration of burosumab exposure was 29.7 (25.0) months. Overall, 25/67 participants (37.3%) experienced ⩾1 adverse event (AE) during follow-up; 83 AEs were reported. There were no deaths, no AEs leading to treatment withdrawal, nor serious AEs related to treatment. The most frequently reported AEs were classified as 'musculoskeletal and connective tissue disorders', with 'pain in extremity' most frequently reported, followed by 'infections and infestations', with 'tooth abscess' the most frequently reported.CONCLUSION: In this first interim analysis of the PASS, covering the initial 2 years of data collection, the safety profile of burosumab is consistent with previously reported safety data. The PASS will provide long-term safety data over its 10-year duration for healthcare providers and participants with XLH that contribute to improvements in the knowledge of burosumab safety.TRIAL REGISTRATION: European Union electronic Register of Post-Authorisation Studies: EUPAS32190.
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| 5. |
- Mughal, M. Zulf, et al.
(författare)
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Burosumab for X-linked hypophosphatemia in children and adolescents : Opinion based on early experience in seven European countries
- 2022
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Ingår i: Frontiers in Endocrinology. - : Frontiers Media S.A.. - 1664-2392. ; 13
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Forskningsöversikt (refereegranskat)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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| 6. |
- Padidela, Raja, et al.
(författare)
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BUR-CL207 : An Open-label, Multicenter, Non-randomized Study to Assess the Safety, Tolerability, Pharmacokinetics and Efficacy of Burosumab in Pediatric Patients from Birth to Less than 1 Year of Age with XLH
- 2021
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Ingår i: Hormone Research in Paediatrics. - : S. Karger. - 1663-2818 .- 1663-2826. ; 94:Suppl. 1, s. 226-226
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: X-linked hypophosphatemia (XLH) is caused by mutations in PHEX which increases serum Fibroblast Growth Factor 23 (FGF23) concentrations leading to phosphate wast-ing and osteomalacia. Burosumab is a recombinant fully human IgG1 monoclonal antibody which selectively inhibits the activity of FGF23. In clinical trials burosumab demonstrated significant clinical improvements in radiological rickets severity, growth, and biochemistry among XLH children aged 1-12 years compared to those continuing on conventional therapy (Imel 2019). Buro-sumab is licensed by the European Medicines Agency for manage-ment of XLH in children >1 year. Early initiation of treatment in XLH improves height (Makitie 2003) and effective and sustained treatment improves dental and musculoskeletal outcomes. Study BUR-CL207 has been designed to evaluate the safety, tolerability, pharmacology and efficacy of burosumab in pediatric patients <12 months.Methods: This study is enrolling and will include approxi-mately 20 XLH infants (<12 months old) with a confirmed PHEXmutation. Baseline fasted serum phosphate below the age-adjusted normal range is required for inclusion. Infants receiving conven-tional therapy will discontinue medications >1 week before com-mencing burosumab treatment and for the duration of study. This study comprises three cohorts with a total treatment period of up to 48 weeks. Subjects will be enrolled into a cohort dependent on their age. Cohorts 1 and 2 for subjects aged: ≥6 months to <12 months, and cohort 3 for subjects <6 months. Burosumab starting doses of 0.4 mg/kg (Cohorts 1 and 3) and 0.8 mg/kg (Cohort 2), administered every two weeks, will be studied in each subgroup in a staggered manner with up to 3 subjects per cohort (final num-ber per cohort will depend on age of eligible patients as enrolled). Burosumab dose adjustments will be determined by serum phos-phate levels. A Data Safety Monitoring Board will review data accrued in each cohort.Outcome Measurements: The primary endpoint is the safety of burosumab in pediatric patients <12 months. The secondary endpoints include: PK assessments and change from baseline in serum phosphate and 1,25(OH)2D, the clinical effects of buro-sumab on growth and prevention and/or healing of rickets and skeletal deformities. Exploratory endpoints include presence and appearance of bone and skeletal XLH related abnormalities in pediatric subjects starting treatment <12 months, anthropometric and motor development in pediatric subjects with XLH and char-acterizing the immunogenicity of burosumab following adminis-tration to pediatric subjects with XLH.BUR-CL207 is conducted in Austria, France, Germany, Italy, Spain, Sweden, UK.
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| 7. |
- Padidela, Raja, et al.
(författare)
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The international X-linked hypophosphataemia (XLH) registry (NCT03193476) : rationale for and description of an international, observational study
- 2020
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Ingår i: Orphanet Journal of Rare Diseases. - : BioMed Central (BMC). - 1750-1172. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: X-linked hypophosphataemia (XLH) is a rare, hereditary, progressive and lifelong phosphate wasting disorder characterised by pathological elevations in fibroblast growth factor (FGF) 23 concentration and activity; XLH has an incidence of approximately 1 in 20-25,000 individuals. Excess FGF23 activity leads to increased phosphate excretion in the kidneys - mediated by downregulation of renal tubular phosphate transporters - and reduced phosphate absorption in the intestines - due to impaired vitamin D activation. This results in impaired bone growth and mineralisation, short and disproportionate stature, leg bowing, musculoskeletal pain, spontaneous dental abscesses, rickets, and osteomalacia. The spectrum of manifestations differs between paediatric and adult patients. Those involved in the treatment of this condition face many challenges, including a lack of robust natural history and demographic data. This multicentre, international, rare-disease patient registry (XLH Registry) was established to address the paucity of data in XLH and to help inform future clinical practice.Results: The XLH Registry collects standard diagnostic and monitoring practice data, including (where applicable) diagnosis and disease progression history, treatment regimens and family history; the protocol does not mandate any interventions or clinical assessments. The XLH Registry aims to recruit 1200 paediatric and adult patients with XLH over 10 years, and several data analyses and peer-reviewed publications are expected to be generated throughout this period. A post-authorisation safety study for Bburosumab, for which the registry Sponsor is the marketing authorisation holder, will be nested as a sub-study within the XLH Registry via a subsequent protocol amendment.Conclusion: The data collected within this rare-disease patient registry will be utilised to synthesise real-world evidence to inform the management of XLH, to improve the quality of life and standard of care of patients living with this rare debilitating disease.
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