Browsing by Author "Jan de Beur, Suzanne M."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item Burosumab for the Treatment of Tumor‐Induced Osteomalacia(Wiley, 2021-04) Jan de Beur, Suzanne M.; Miller, Paul D.; Weber, Thomas J.; Peacock, Munro; Insogna, Karl; Kumar, Rajiv; Rauch, Frank; Luca, Diana; Cimms, Tricia; Scott Roberts, Mary; Martin, Javier San; Carpenter, Thomas O.; Medicine, School of MedicineTumor-induced osteomalacia (TIO) is caused by phosphaturic mesenchymal tumors producing fibroblast growth factor 23 (FGF23) and is characterized by impaired phosphate metabolism, skeletal health, and quality of life. UX023T-CL201 is an ongoing, open-label, phase 2 study investigating the safety and efficacy of burosumab, a fully human monoclonal antibody that inhibits FGF23, in adults with TIO or cutaneous skeletal hypophosphatemia syndrome (CSHS). Key endpoints were changes in serum phosphorus and osteomalacia assessed by transiliac bone biopsies at week 48. This report focuses on 14 patients with TIO, excluding two diagnosed with X-linked hypophosphatemia post-enrollment and one with CSHS. Serum phosphorus increased from baseline (0.52 mmol/L) and was maintained after dose titration from week 22 (0.91 mmol/L) to week 144 (0.82 mmol/L, p < 0.0001). Most measures of osteomalacia were improved at week 48: osteoid volume/bone, osteoid thickness, and mineralization lag time decreased; osteoid surface/bone surface showed no change. Of 249 fractures/pseudofractures detected across 14 patients at baseline, 33% were fully healed and 13% were partially healed at week 144. Patients reported a reduction in pain and fatigue and an increase in physical health. Two patients discontinued: one to treat an adverse event (AE) of neoplasm progression and one failed to meet dosing criteria (receiving minimal burosumab). Sixteen serious AEs occurred in seven patients, and there was one death; all serious AEs were considered unrelated to treatment. Nine patients had 16 treatment-related AEs; all were mild to moderate in severity. In adults with TIO, burosumab exhibited an acceptable safety profile and was associated with improvements in phosphate metabolism and osteomalacia.Item Global guidance for the recognition, diagnosis, and management of tumor-induced osteomalacia(Wiley, 2023) Jan de Beur, Suzanne M.; Minisola, Salvatore; Xia, Wei-bo; Abrahamsen, Bo; Body, Jean-Jacques; Brandi, Maria Luisa; Clifton-Bligh, Roderick; Collins, Michael; Florenzano, Pablo; Houillier, Pascal; Imanishi, Yasuo; Imel, Erik A.; Khan, Aliya A.; Zillikens, M. Carola; Fukumoto, Seiji; Medicine, School of MedicineTumor-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.Item Healthcare Resource Use Associated With Tumor-Induced Osteomalacia: A Literature Review(Oxford University Press, 2024) Jan de Beur, Suzanne M.; Dahir, Kathryn M.; Imel, Erik A.; Zanchetta, María Belén; Williams, Angela; Li, Zhiyi; Webb, Neil; Crowe, Victoria; Johnson, Ben; Carpenter, Thomas O.; Medicine, School of MedicineContext: Tumor-induced osteomalacia (TIO) is an ultra-rare, paraneoplastic syndrome caused by tumors that secrete fibroblast growth factor 23 (FGF23). Initial signs and musculoskeletal symptoms can be nonspecific and unrecognized, leading to long delays in diagnosis and treatment, and resulting in severe and progressive disability in patients with TIO. Objective: This review aimed to identify published evidence on healthcare resource use in TIO to better understand the burden of the disease. Evidence acquisition: A targeted literature review was conducted to identify publications reporting on disease characteristics and healthcare resource use associated with TIO. Evidence synthesis: In total, 414 publications were included in the review, of which 376 were case reports. From the case reports, data on 621 patients were extracted. These patients had a mean (SD) age of 46.3 (15.8) years; 57.6% were male. Mean time from first symptoms to diagnosis of TIO was 4.6 (4.7) years and, in cases where imaging tests were reported, patients underwent a mean of 4.1 (2.7) procedures. Tumor resection was attempted in 81.0% of patients and successful in 67.0%. Fracture was reported in 49.3% of patients. Results from association analyses demonstrated that longer time to diagnosis was associated with poorer tumor resection outcomes and a higher probability of tumor recurrence. Unfavorable tumor resection outcomes were associated with greater use of pharmacologic treatment and a greater likelihood of orthopedic surgery. Conclusion: TIO is associated with a substantial healthcare resource burden. Improvements in the diagnostic process could lead to better management of TIO, thereby benefiting patients and reducing that burden.Item Nephrocalcinosis and kidney function in children and adults with X-linked hypophosphatemia: baseline results from a large longitudinal study(Oxford University Press, 2024) Portale, Anthony A.; Ward, Leanne; Dahir, Kathryn; Florenzano, Pablo; Ing, Steven W.; Jan de Beur, Suzanne M.; Martin, Regina M.; Meza-Martinez, Adriana I.; Paloian, Neil; Ashraf, Ambika; Dixon, Bradley P.; Khan, Aliya; Langman, Craig; Chen, Angel; Wang, Christine; Scott Roberts, Mary; Tandon, P. K.; Bedrosian, Camille; Imel, Erik A.; Medicine, School of MedicineBackground: In patients with X-linked hypophosphatemia (XLH), conventional therapy with oral phosphate salts and active vitamin D has been associated with nephrocalcinosis. However, the nature of the relationships among XLH, its treatment, nephrocalcinosis, and kidney function remain poorly understood. Methods: Renal ultrasounds were performed and glomerular filtration rates were estimated (eGFR) at baseline in burosumab-naïve patients with XLH who participated in burosumab clinical trials (NCT02181764, NCT02526160, NCT02537431, NCT02163577, NCT02750618, NCT02915705) or enrolled in the XLH Disease Monitoring Program (XLH-DMP; NCT03651505). In this cross-sectional analysis, patient, disease, and treatment characteristics were described among patients with and without nephrocalcinosis. Results: The analysis included 196 children (mean [SD] age 7.6 [4.0] yr) and 318 adults (40.3 [13.1] yr). Mean (SD) height z-score was -1.9 (1.2) for children and -2.3 (1.7) for adults. Nearly all children (97%) and adults (94%) had previously received conventional therapy. Nephrocalcinosis was detected in 22% of children and 38% of adults. In children, reduced eGFR <90 mL/min/1.73 m2 was more prevalent in those with nephrocalcinosis (25%) than in those without (11%), a finding that was not observed in adults. Children with nephrocalcinosis had lower mean values of TmP/GFR (p<.05), serum 1,25(OH)2D (p<.05), and eGFR (p<.001) and higher mean serum calcium concentrations (p<.05) than did those without nephrocalcinosis. Adults with nephrocalcinosis had lower mean serum phosphorus (p<.01) and 1,25(OH)2D (p<.05) concentrations than those without. Exploratory logistic regression analyses revealed no significant associations between the presence of nephrocalcinosis and other described patient or disease characteristics. Conclusions: Nephrocalcinosis was observed in nearly one-quarter of children and more than one-third of adults with XLH. Further study is needed to better understand the predictors and long-term consequences of nephrocalcinosis, with surveillance for nephrocalcinosis remaining important in the management of XLH.Item Reply to: Burosumab for Tumor-Induced Osteomalacia: not Enough of a Good Thing(Wiley, 2021) Jan de Beur, Suzanne M.; Miller, Paul D.; Weber, Thomas J.; Peacock, Munro; Insogna, Karl; Kumar, Rajiv; Rauch, Frank; Luca, Diana; Cimms, Tricia; Scott Roberts, Mary; San Martin, Javier; Carpenter, Thomas O.; Medicine, School of Medicine