Dataset Information

Fibroblast growth factor-23 in early chronic kidney disease: additional support in favor of a phosphate-centric paradigm for the pathogenesis of secondary hyperparathyroidism.

ABSTRACT: The discovery of fibroblast growth factor-23 (FGF-23) and the elucidation of its function as a phosphaturic and 1,25(OH)2VitD counter-regulatory hormone provides a new conceptual framework for the understanding of the pathogenesis of secondary hyperparathyroidism. This study aims to elucidate the complex associations between FGF-23, parathyroid hormone (PTH), 1,25(OH)2D, and phosphate in patients with early-stage chronic kidney disease (CKD) and to provide clinical evidence in favor of the new phosphate-centric paradigm for the pathogenesis of secondary hyperparathyroidism.Serum biointact PTH and FGF-23, 25(OH)D, 1,25(OH)2D, calcium, phosphate, 24-hour urine excretion of phosphate and calcium, and urinary fractional excretion of phosphate were determined in a cross-sectional study including 125 patients with CKD stages 1 to 3.Serum phosphate levels showed an inverse association with estimated GFR (eGFR), but were within the normal range in all but one patient. FGF-23 and PTH were inversely associated with eGFR, even in the subgroup of patients with CKD stages 1 and 2. High FGF-23 levels were significantly more prevalent than high PTH levels. The urinary fractional excretion of phosphate was highest in patients with both a high serum FGF-23 and PTH level. Increased FGF-23 and phosphate and decreased 25(OH)D were independently associated with decreased 1,25(OH)2D.Our data are in favor of the new paradigm for the pathogenesis of secondary hyperparathyroidism according to which a reduced phosphate excretion capacity is the principal abnormality that initiates secondary hyperparathyroidism.

SUBMITTER: Evenepoel P

PROVIDER: S-EPMC2893066 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature

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Fibroblast growth factor-23 in early chronic kidney disease: additional support in favor of a phosphate-centric paradigm for the pathogenesis of secondary hyperparathyroidism.

Evenepoel Pieter P Meijers Björn B Viaene Liesbeth L Bammens Bert B Claes Kathleen K Kuypers Dirk D Vanderschueren Dirk D Vanrenterghem Yves Y

Clinical journal of the American Society of Nephrology : CJASN 20100506 7

<h4>Background and objectives</h4>The discovery of fibroblast growth factor-23 (FGF-23) and the elucidation of its function as a phosphaturic and 1,25(OH)2VitD counter-regulatory hormone provides a new conceptual framework for the understanding of the pathogenesis of secondary hyperparathyroidism. This study aims to elucidate the complex associations between FGF-23, parathyroid hormone (PTH), 1,25(OH)2D, and phosphate in patients with early-stage chronic kidney disease (CKD) and to provide clini ...[more]

PMID: 20448073

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Project description:Background and objectivesDirect comparison of cinacalcet and vitamin D analogs as monotherapies to lower parathyroid hormone (PTH) levels has not been undertaken.Design, setting, participants, & measurementsThis was a prospective, multicenter, phase 4, randomized, open-label study that enrolled participants from 2010 to 2012. Adult participants (n=312) on hemodialysis with PTH >450 pg/ml were randomized 1:1 to 12 months of treatment with either cinacalcet (n=155) or vitamin D analogs (n=157) to evaluate the mean percentage change in plasma PTH level (primary end point) and the proportion of participants achieving plasma PTH <300 pg/ml or a ≥30% decrease in PTH (secondary end points). A preplanned analysis to determine whether there were important region-by-treatment interactions was also undertaken.ResultsBaseline mean PTH was 846 pg/ml (n=155) for cinacalcet and 816 pg/ml (n=157) for vitamin D analog therapy. The mean (95% confidence interval) percentage change from baseline in PTH was -12.1% (-20.0% to -4.1%) in the cinacalcet arm and -7.0% (-14.9% to 0.8%) in the vitamin D analog arm, a difference of -5.0% (-15.4% to 5.4%) (P=0.35). Similarly, there was no difference in achievement of secondary efficacy end points between arms (19.4% and 15.3% of participants with PTH≤300 pg/ml and 42.6% and 33.8% of participants had a PTH reduction >30% in the cinacalcet and vitamin D analog arms, respectively). A prespecified analysis revealed a large treatment-by-region interaction, with nominally greater response to cinacalcet compared with vitamin D analogs in non-United States participants (US versus non-US participants, P<0.001). Hypocalcemia was more common in the cinacalcet arm, whereas hypercalcemia and hyperphosphatemia occurred more often in the vitamin D analog arm.ConclusionsParticipants had similar modest reductions in PTH with either cinacalcet or vitamin D analog monotherapy over 52 weeks of treatment, but effects varied by region. Treatments differed with regard to effect on calcium and phosphorus levels.

Project description:Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome caused by ectopic production of fibroblast growth factor 23 (FGF23) by phosphaturic mesenchymal tumors (PMTs). Acting on renal tubule cells, excess FGF23 decreases phosphate reabsorption and 1,25-dihydroxy-vitamin D (1,25D) production, leading to hypophosphatemia, impaired bone mineralization, pain, and fractures. Fibronectin 1-fibroblast growth factor receptor 1 (FN1-FGFR1) gene fusions have been identified as possible drivers in up to 40% of resected PMTs. Based on the presumptive role of FGFR1 signaling by chimeric FN1-FGFR1 proteins, the effectiveness of infigratinib, a FGFR1-3 tyrosine kinase inhibitor, was studied in an open-label, single-center, phase 2 trial. The primary endpoint was persistent normalization of blood phosphate and FGF23 after discontinuation. Four adults with TIO (two nonlocalized, two nonresectable PMTs) were treated with daily infigratinib for up to 24 weeks. All patients had a favorable biochemical response that included reduction in intact FGF23, and normalization of blood phosphate and 1,25D. However, these effects disappeared after drug discontinuation with biochemistries returning to baseline; no patients entered biochemical remission. In the two patients with identifiable tumors, 68Gallium (68Ga)-DOTATATE and 18Fluoride (18F)-Fluorodeoxyglucose (FDG) PET/CT scans showed a decrease in PMT activity without change in tumor size. Patients experienced mild to moderate, treatment-related, dose-limiting adverse events (AEs), but no serious AEs. Three patients had dose interruptions due to AEs; one patient continued on a low dose for the entire 24 weeks and one patient stopped therapy at 17 weeks due to an AE. The study closed early due to a failure to meet the primary endpoint and a higher-than-expected incidence of ocular AEs. Infigratinib treatment lowered FGF23, increased blood phosphate, and suppressed PMT activity, confirming the role of FGFR signaling in PMT pathogenesis. However, treatment-related AEs at efficacy doses and disease persistence on discontinuation support restricting the use of infigratinib to patients with life-limiting metastatic PMTs. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Dataset Information

Fibroblast growth factor-23 in early chronic kidney disease: additional support in favor of a phosphate-centric paradigm for the pathogenesis of secondary hyperparathyroidism.

Publications

Fibroblast growth factor-23 in early chronic kidney disease: additional support in favor of a phosphate-centric paradigm for the pathogenesis of secondary hyperparathyroidism.

Similar Datasets

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