scholarly journals Favorable Effects of Burosumab on Fibroblast Growth Factor 23-Related Osteomalacia: A Case Report

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A194-A194
Author(s):  
Yuki Oe ◽  
Hiraku Kameda ◽  
Hiroshi Nomoto ◽  
Keita Sakamoto ◽  
Takeshi Soyama ◽  
...  

Abstract Background: Fibroblast growth factor 23 (FGF23) decreases serum phosphate levels by inhibiting proximal tubular phosphate reabsorption and intestinal phosphate absorption by decreasing serum 1,25-dihydroxyvitamin D level, thereby regulating phosphate metabolism. Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by FGF23 overproduction by tumor tissue. Resecting the responsible tumor is a radical treatment for TIO. When the responsible tumor is undetectable, phosphate and active vitamin D administration is recommended. However, supplementation alone is frequently insufficient to maintain phosphate levels and it is difficult to prevent the complications associated with medical therapy, including hypercalciuria and nephrocalcinosis. Recently, burosumab, a human monoclonal anti-FGF23 antibody, has been approved in Japan as a therapeutic agent for FGF23-related hypophosphatemia. Here, we present a patient with TIO effectively treated with burosumab in the absence of identification of tumour location. Clinical case: A 47-year-old female developed pain and edema of the feet; however, the cause could not be determined at local hospitals. Afterwards, she developed marked bone atrophy in the feet and was referred to our hospital. Her age at symptom onset, hypophosphatemia (serum P, 1.9 mg/dl, 2.7 mg/dl < n < 4.6 mg/dl), high serum FGF23 level (630 pg/ml, 16 pg/ml < n < 69 pg/ml), and decreased 1,25-dihydroxyvitamin D level (12.9 pg/ml, 20 pg/ml < n < 60 pg/ml) indicated FGF23-related osteomalacia. She was not having any medication at the time of diagnosis, including saccharified iron oxide or iron polymaltose. Urinary phosphate excretion increased without renal tubular defect; therefore, hypophosphatemic osteomalacia was diagnosed. MRI showed high signal intensity in the talus, sacral, and L5 vertebral regions, indicating multiple pseudofractures. Comprehensive imaging studies, including systemic CT scan and 111In-pentetreotide scintigraphy, did not reveal any tumors despite the suspicion of TIO. Next, we performed systemic venous sampling, which revealed high FGF23 level in the left external iliac vein. Second venous sampling limited to the left lower limb exhibited high FGF23 level in the posterior tibial vein. However, an additional imaging study limited to the left foot could not identify any tumors. Genetic variation was negative for potentially responsible genes, including PHEX and FGF23. We decided to administer burosumab to normalize serum phosphate level without phosphate supplementation. Within 2 months, pain was relieved and the visual analog scale scores also improved from 10 to 6. Moreover, bone MRI showed improved pseudofractures. Conclusion: Burosumab administration was effective for TIO of unknown origin, and it improved not only laboratory findings but also clinical symptoms in this case.

2012 ◽  
Vol 28 (1) ◽  
pp. 46-55 ◽  
Author(s):  
Justine Bacchetta ◽  
Jessica L Sea ◽  
Rene F Chun ◽  
Thomas S Lisse ◽  
Katherine Wesseling-Perry ◽  
...  

2009 ◽  
Vol 23 (3) ◽  
pp. 368-374 ◽  
Author(s):  
Tetsuhiko Sato ◽  
Masafumi Fukagawa ◽  
Kazuharu Uchida ◽  
Akio Katayama ◽  
Takaharu Nagasaka ◽  
...  

2019 ◽  
Vol 14 (10) ◽  
pp. 1475-1483 ◽  
Author(s):  
Wan-Chuan Tsai ◽  
Hon-Yen Wu ◽  
Yu-Sen Peng ◽  
Shih-Ping Hsu ◽  
Yen-Ling Chiu ◽  
...  

Background and objectivesThe short-term effects of low-phosphate diets on fibroblast growth factor 23 (FGF23) level and the optimal amount of dietary phosphate restriction in patients undergoing hemodialysis remain unknown.Design setting, participants, & measurementsThis was a randomized, active-controlled trial with a crossover design that included 35 adults with ESKD undergoing thrice-weekly hemodialysis and with a serum phosphate level >5.5 mg/dl or between 3.5 and 5.5 mg/dl with regular phosphate binder use at a hemodialysis unit of tertiary teaching hospital in Taiwan. Subjects were randomized 1:1 to receive a very-low-phosphate diet, with a phosphate-to-protein ratio of 8 mg/g, or a low-phosphate diet, with a phosphate-to-protein ratio of 10 mg/g for 2 days, each with a 5-day washout during which subjects adhered to their usual diet. The primary outcome measure was mean difference in change-from-baseline intact FGF23 level between intervention groups. Secondary outcomes included difference in change-from-baseline serum phosphate, intact parathyroid hormone (PTH), and C-terminal FGF23 level between intervention groups.ResultsThere was no significant difference in the mean change-from-baseline in intact FGF23 levels between the two study diets. The very-low-phosphate diet significantly lowered serum phosphate (mean difference, 0.6 mg/dl; 95% confidence interval [95% CI], 0.2 to 1.0; P=0.002). There were no significant differences in change-from-baseline intact PTH and C-terminal FGF23 levels between the two study diets.ConclusionsOver the 2-day period, the FGF23-lowering effect of the very-low-phosphate diet is similar to that of the low-phosphate diet. The very-low-phosphate diet has an additional phosphate-lowering effect compared with the low-phosphate diet.


2018 ◽  
Vol 47 (6) ◽  
pp. 406-414 ◽  
Author(s):  
Noriaki Maruyama ◽  
Tomoyasu Otsuki ◽  
Yoshinori Yoshida ◽  
Chinami Nagura ◽  
Maki Kitai ◽  
...  

Background: Serum phosphate and vitamin D receptor activator regulate fibroblast growth factor 23 (FGF23), and iron may modulate FGF23 metabolism. The aim of the present study was to elucidate the effects of ferric citrate hydrate and lanthanum carbohydrate on serum FGF23 levels in hemodialysis patients. Methods: This prospective, open-label, multicenter study enrolled 60 patients on hemodialysis treated with lanthanum carbonate. Patients were randomly assigned to 2 groups: those switching from lanthanum carbonate to ferric citrate hydrate (ferric citrate group, n = 30) or those continuing lanthanum carbonate (control group, n = 30). Patients were monitored for 24 weeks. Endpoints included changes in FGF23, phosphate, and the dose of erythropoiesis stimulating agent (ESA), erythropoietin responsiveness index (ERI), and adverse events. Results: FGF-23 levels were significantly lower in the ferric citrate group compared with the levels in the control group (change from baseline –6,160 vs. –1,118 pg/mL; p = 0.026). There were no significant changes in serum calcium, phosphate, and intact parathyroid hormone levels in either group. The ferric citrate group had significantly increased serum iron, ferritin, and transferrin saturation. Hemoglobin levels were significantly elevated, and the dose of ESA was significantly decreased in the ferric citrate group but not in the control group. ERI and the dose of intravenous saccharated ferric oxide were significantly lower in the ferric citrate group compared with those of the control group (p = 0.015 and p = 0.002). Conclusion: In patients on hemodialysis, 24-week treatment with ferric citrate hydrate resulted in significant reduction in FGF23 and ERI independently of serum phosphate level.


Biomedika ◽  
2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Intan Herlina ◽  
Bambang Purwanto ◽  
Sugiarto Sugiarto

Penyebab utama morbiditas dan mortalitas pada pasien Penyakit Ginjal Kronik adalah insiden kardiovaskuler yang didasari oleh proses aterosklerosis yang menyebabkan meningkatnya morbiditas dan mortalitas. Ginjal merupakan tempat utama sintesa 1,25 Dihydroxyvitamin D (Calcitriol), sehingga dengan adanya kerusakan ginjal menyebabkan defisiensi 1,25 Dihydroxyvitamin D (Calcitriol). Pada pasien Penyakit Ginjal Kronik terjadi peningkatan Fibroblast Growth Factor-23 dan Albuminuria akibat dari aktifitas Renin Angiotensin Aldosteron Sistem. Aktifitas RAAS mempengaruhi 1,25 Dihydroxy vitamin D (Calcitriol), Fibroblast Growth Factor-23 melalui Angiotensin 2 dengan cara menghambat reseptor Angiotensin I (AT1) melalui Nicotinmide Adenine Dinucleotide Phosphate Oxidase (NADPH Oksidase) dan Stress Oxidativ. Beberapa penelitian menyimpulkan pemberian 1,25 Dihydroxyvitamin D (Calcitriol) mempunyai efek renoprotektif, anti inflamasi dan antiproteinuric dengan cara menghambat reseptor Angoitensin I (AT1) sehingga mengakibatkan menurunnya albuminuria. Tujuan Penelitian ini adalah untuk membuktikan pemberian 1,25 Dihydroxyvitamin D (Calcitriol) dapat menurunkan kadar Fibroblas Growth Factor-23 dan albuminuria pada pasien Penyakit Ginjal Kronik stadium V yang menjalani hemodialisis. Penelitian ini merupakan penelitian eksperimen dengan randomisasi, subyek penelitian 30 orang, dibagi dalam dua kelompok sampel, kelompok plasebo 15 orang dan kelompok perlakuan 15 orang. Dalam perjalanan, kelompok placebo drop out 4 pasien karena keluarga pasien tidak menyetujui untuk melanjutkan penelitian dan satu lagi mengalami perburukan, sehingga jumlah sampel menjadi 26 orang, terbagi menjadi kelompok placebo sebanyak 11 orang yang diberi placebo dan kelompok perlakuan 15 orang diberi calcitriol 1x0,5 μg peroral selama 4 minggu. Karakteristik penelitian yang berupa variabel kualitatif, uji homogenitas dilakukan menggunakan uji Chi Square. Uji beda dua Rerata menggunakan uji t pada p<0.005. Pada kelompok plasebo (n=11) ; Kadar Fibroblast Growth Factor-23 sebelum dan sesudah perlakuan (876,24±795,93 RU/mL vs 1235,69±791,71 RU/mL; p=0,059) dan Albuminuria (72,30±195,06 μg/ mg vs 320,14±208,90 μg/mg; p=0,001). Pada kelompok perlakuan (n=15); Kadar Fibroblast Growth Factor-23 sebelum dan sesudah perlakuan (1210,96±845,97 RU/mL vs 612,33±487,32 RU/mL; p=0,002) dan Albuminuria (206,63±327,25 μg/mg vs 192,89±316,00 μg/mg; p=0,001). Terdapat perbedaan yang bermakna pada selisih ratarata kadar Fibroblast Growth Factor-23 (Delta-FGF-23) sebelum dan sesudah perlakuan pada kelompok placebo vs kelompok perlakuan (-359,45±560,23 RU/mL vs 598,63±608,27 RU/mL; p=0,001) dan selisih rata-rata Albuminuria (Delta-albuminuria) sebelum dan sesudah perlakuan pada kelompok placebo vs kelompok perlakuan (-247,84±189,48 μg/mg vs 13,73±23,15μg/mg;p=0,001. Pemberian suplementasi 1,25 Dihydroxyvitamin D (calcitriol) menurunkan kadar FGF-23 albuminuria secara bermakna pada pasien penyakit ginjal kronik stadium V yang menjalani hemodialisisKata Kunci: Penyakit Ginjal Kronis Stadium V, 1,25 Dihydroxyvitamin D (Calcitriol), Fibroblast Growth Factor-23, Albuminuria


2007 ◽  
Vol 92 (5) ◽  
pp. 1943-1947 ◽  
Author(s):  
Shoji Ichikawa ◽  
Vincent Guigonis ◽  
Erik A. Imel ◽  
Mélanie Courouble ◽  
Sophie Heissat ◽  
...  

Abstract Context: Hyperostosis-hyperphosphatemia syndrome (HHS) is a rare metabolic disorder characterized by hyperphosphatemia and localized hyperostosis. HHS is caused by mutations in GALNT3, which encodes UDP-N-acetyl-α-d-galactosamine:polypeptide N- acetylgalactosaminyltransferase 3. Familial tumoral calcinosis (TC), characterized by ectopic calcifications and hyperphosphatemia, is caused by mutations in the GALNT3 or fibroblast growth factor 23 (FGF23) genes. Objective: Our objective was to identify mutations in FGF23 or GALNT3 and determine serum FGF23 levels in an HHS patient. Design: Mutation detection in FGF23 and GALNT3 was performed by DNA sequencing, and serum FGF23 concentrations were measured by ELISA. Patients or Other Participants: A 5-year-old French boy with HHS and his family members participated. Results: The patient presented with painful cortical lesions in his leg. Radiographs of the affected bone showed diaphyseal hyperostosis. The lesional tissue comprised trabeculae of immature, woven bone surrounded by fibrous tissue. Biochemistry revealed elevated phosphate, tubular maximum rate for phosphate reabsorption per deciliter of glomerular filtrate, and 1,25-dihydroxyvitamin D levels. The patient was a compound heterozygote for two novel GALNT3 mutations. His parents and brother were heterozygous for one of the mutations and had no biochemical abnormalities. Intact FGF23 level in the patient was low normal, whereas C-terminal FGF23 was elevated, a pattern similar to TC. Conclusion: The presence of GALNT3 mutations and elevated C-terminal, but low intact serum FGF23, levels in HHS resemble those seen in TC, suggesting that HHS and TC are different manifestations of the same disorder. The absence of biochemical abnormalities in the heterozygous individuals suggests that one normal allele is sufficient for secretion of intact FGF23.


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