Ferric citrate for the treatment of hyperphosphatemia and iron deficiency anaemia in patients with NDD-CKD: a systematic review and meta-analysis

Background: The application of ferric citrate therapy has yielded unexpected benefits in recent years for Chronic kidney disease patients suffering from hyperphosphatemia and iron deficiency -anaemia. Despite this, earlier research on the impact of ferric citrate on NDD-CKD has been contentious. Objective: The goal of the meta-analysis is to evaluate the evidence regarding the advantages and dangers of ferric citrate for the treatment of hyperphosphatemia and iron deficiency anaemia in NDD-CKD patients. Methods: Between the start of the study and June 2022, we searched PubMed, Embase, Cochrane, EBSCO, Scopus, Web of Science, Wan Fang Data, CNKI, and VIP databases for randomised controlled trials of iron citrate for hyperphosphatemia and anaemia in patients with NDD-CKD. For binary categorical data, risk ratios (OR) were employed, and for continuous variables, weighted mean differences The effect sizes for both count and measurement data were expressed using 95% confidence intervals Results: The meta-analysis includes eight trials with a total of 1281 NDD-CKD patients. The phosphorus-lowering effect of ferric citrate was greater compared to the control group (WMD, -0.55, 95% CI, -0.81 to -0.28; I2 = 86%, p < 0.001). Calcium (WMD, 0.092; 95% CI, -0.051 to 0.234; p > 0.05; I2 = 61.9%), PTH (WMD, -0.10; 95% CI, -0.44 to 0.23; I2 = 75%, p > 0.05) and iFGF23 (WMD, -7.62; 95% CI, -21.18 to 5.94; I2 = 20%, p > 0.05) levels were not statistically different after ferric citrate treatment compared to control treatment. Furthermore, ferric citrate increased iron reserves and haemoglobin. The ferric citrate group had considerably greater levels than the controls. Ferric citrate, on the other hand, may raise the risk of constipation, diarrhoea, and nausea. Conclusion: This meta-analysis found that ferric citrate had a beneficial effect in the treatment of NDD-CKD, particularly in reducing blood phosphorus levels when compared to a control intervention. It also shown that ferric citrate has a favourable effect on iron intake and anaemia management. In terms of safety, ferric citrate may increase the likelihood of gastrointestinal side effects.

Djulis Hull Enhances the Efficacy of Ferric Citrate Supplementation via Restoring Normal Iron Efflux through the IL-6-Hepcidin-Ferroportin Pathway in High-Fat-Diet-Induced Obese Rats

Obesity-related functional iron disorder remains a major nutritional challenge. We evaluated the effects of djulis hull (DH) on iron metabolism in 50% high-fat-diet-induced obese rats supplemented with ferric citrate (2 g iron/kg diet) for 12 weeks. DH supplementation (5, 10, 15% dry weight/kg diet) significantly increased serum and hepatic iron but decreased appetite hormones, body weight, hepcidin, and liver inflammation (all p < 0.05). The Spearman correlation showed that appetite hormones were negatively associated with iron but positively correlated with liver hepcidin (all p < 0.05). A Western blot analysis showed that DH significantly downregulated hepatic hepcidin through the IL-6-JAK-STAT3 and enhanced ferroportin (Fpn) via the Keap1-Nrf2 and PHD2-HIF-2α. An in vitro study revealed that major bioactive compounds of DH, hexacosanol, and squalene suppressed LPS-induced IL-6 and hepcidin but enhanced Fpn expression in activated THP-1 cells. In conclusion, DH may exert nutraceutical properties for the treatment of functional iron disorder and restoration of iron efflux may have beneficial effects on weight control.

The Role of Iron-Based Phosphate Binder in the Treatment of Hyperphosphatemia

Hyperphosphatemia is a well-known complication of kidney disease. Phosphate binders are a mainstay treatment, but despite the existence of several phosphate binders, there is no one best approach to manage hyperphosphatemia. Phosphate binders are calcium-based, non-calcium- based, and others. While calcium-based phosphate binders are used frequently, they may cause hypercalcemia. Conversely, lanthanum carbonate and sevelamer were not linked to hypercalcemia but are costlier. The most recently developed class of phosphate binders is the ironbased ferric citrate and sucroferric oxyhydroxide. These have an important role in controlling phosphate levels due to their ability to lower the phosphate while concurrently providing iron sources. This review provides pharmacological profiles of different phosphate binders and their clinical usages, and further elaborates on their place in hyperphosphatemia management.

Phosphate-Trapping Liposomes for Long-Term Management of Hyperphosphatemia

Hyperphosphatemia is a typical complication of end-stage renal disease, characterized by elevated and life-threatening serum phosphate levels. Hemodialysis does not enable sufficient clearance of phosphate, due to slow cell-to-plasma kinetics of phosphate ions; moreover, dietary restrictions and conventional treatment with oral phosphate binders have low success rates, together with adverse effects. Here, we developed a new concept of phosphate-trapping liposomes, to improve and prolong the control over serum phosphate levels. We designed liposomes modified with polyethylene glycol and encapsulated with the phosphate binder ferric citrate (FC liposomes). These liposomes were found to trap phosphate ions in their inner core, and thereby lower free phosphate ion concentrations in solution and in serum. The FC liposomes showed higher phosphate binding ability as phosphate concentrations increased. Moreover, these liposomes showed a time-dependent increase in uptake of phosphate, up to 25 h in serum. Thus, our findings demonstrate effective long-term phosphate trapping by FC liposomes, indicating their potential to reduce serum phosphate toxicity and improve current management of hyperphosphatemia.

Effects of ferric citrate and intravenous iron sucrose on markers of mineral, bone, and iron homeostasis in a rat model of CKD-MBD

BACKGROUND

Anemia and chronic kidney disease-mineral and bone disorder (CKD-MBD) are common and begin early in CKD. Limited studies have concurrently compared the effects of ferric citrate (FC) versus intravenous (IV) iron on CKD-MBD and iron homeostasis in moderate CKD.

METHODS

We tested the effects of 10 weeks of 2% FC versus IV iron sucrose in rats with moderate CKD (Cy/+ male rat) and untreated normal (NL) littermates. Outcomes included a comprehensive assessment of CKD-MBD, iron homeostasis and oxidative stress.

RESULTS

CKD rats had azotemia, elevated phosphorus, parathyroid hormone and fibroblast growth factor-23 (FGF23). Compared with untreated CKD rats, treatment with FC led to lower plasma phosphorus, intact FGF23 and a trend (P = 0.07) toward lower C-terminal FGF23. FC and IV iron equally reduced aorta and heart calcifications to levels similar to NL animals. Compared with NL animals, CKD animals had higher bone turnover, lower trabecular volume and no difference in mineralization; these were unaffected by either iron treatment. Rats treated with IV iron had cortical and bone mechanical properties similar to NL animals. FC increased the transferrin saturation rate compared with untreated CKD and NL rats. Neither iron treatment increased oxidative stress above that of untreated CKD.

CONCLUSIONS

Oral FC improved phosphorus homeostasis, some iron-related parameters and the production and cleavage of FGF23. The intermittent effect of low-dose IV iron sucrose on cardiovascular calcification and bone should be further explored in moderate-advanced CKD.

Segregating the effects of ferric citrate-mediated iron utilization and FGF23 in a mouse model of CKD

Ferric citrate (FC) is an approved therapy for chronic kidney disease (CKD) patients as a phosphate (Pi) binder for dialysis-dependent CKD, and for iron deficiency anemia (IDA) in non-dialysis CKD. Elevated Pi and IDA both lead to increased FGF23, however, the roles of iron and FGF23 during CKD remain unclear. To this end, iron and Pi metabolism were tested in a mouse model of CKD (0.2% adenine) ± 0.5% FC for 6 weeks, with and without osteocyte deletion of Fgf23 (flox-Fgf23/Dmp1-Cre). Intact FGF23 (iFGF23) increased in all CKD mice but was lower in Cre+ mice with or without FC, thus the Dmp1-Cre effectively reduced FGF23. Cre+ mice fed AD-only had higher serum Pi than Cre- pre- and post-diet, and the Cre+ mice had higher BUN regardless of FC treatment. Total serum iron was higher in all mice receiving FC, and liver Tfrc, Bmp6, and hepcidin mRNAs were increased regardless of genotype; liver IL-6 showed decreased mRNA in FC-fed mice. The renal 1,25-dihydroxyvitamin D (1,25D) anabolic enzyme Cyp27b1 had higher mRNA and the catabolic Cyp24a1 showed lower mRNA in FC-fed mice. Finally, mice with loss of FGF23 had higher bone cortical porosity, whereas Raman spectroscopy showed no changes in matrix mineral parameters. Thus, FC- and FGF23-dependent and -independent actions were identified in CKD; loss of FGF23 was associated with higher serum Pi and BUN, demonstrating that FGF23 was protective of mineral metabolism. In contrast, FC maintained serum iron and corrected inflammation mediators, potentially providing ancillary benefit.

Enteral ferric citrate absorption is dependent on the iron transport protein ferroportin

Ferric citrate is approved as an iron replacement product in patients with non-dialysis chronic kidney disease and iron deficiency anemia. Ferric citrate-delivered iron is enterally absorbed, but the specific mechanisms involved have not been evaluated, including the possibilities of conventional, transcellular ferroportin-mediated absorption and/or citrate-mediated paracellular absorption. Here, we first demonstrate the efficacy of ferric citrate in high hepcidin models, including Tmprss6 knockout mice (characterized by iron-refractory iron deficiency anemia) with and without adenine diet-induced chronic kidney disease. Next, to assess whether or not enteral ferric citrate absorption is dependent on ferroportin, we evaluated the effects of ferric citrate in a tamoxifen-inducible, enterocyte-specific ferroportin knockout murine model (Villin-Cre-ER^T2, Fpn^flox/flox). In this model, ferroportin deletion was efficient, as tamoxifen injection induced a 4000-fold decrease in duodenum ferroportin mRNA expression, with undetectable ferroportin protein on Western blot of duodenal enterocytes, resulting in a severe iron deficiency anemia phenotype. In ferroportin-deficient mice, three weeks of 1% ferric citrate dietary supplementation, a dose that prevented iron deficiency in control mice, did not improve iron status or rescue the iron deficiency anemia phenotype. We repeated the conditional ferroportin knockout experiment in the setting of uremia, using an adenine nephropathy model, where three weeks of 1% ferric citrate dietary supplementation again failed to improve iron status or rescue the iron deficiency anemia phenotype. Thus, our data suggest that enteral ferric citrate absorption is dependent on conventional enterocyte iron transport by ferroportin and that, in these models, significant paracellular absorption does not occur.

The Ferric Citrate Uptake System Encoded in a Novel bla CTX-M-3- and bla TEM-1-Harboring Conjugative Plasmid Contributes to the Virulence of Escherichia coli

Escherichia coli is one major cause of bacterial infections and can horizontally acquire antimicrobial resistance and virulence genes through conjugation. Because conjugative plasmids can rapidly spread among bacteria of different species, the plasmids carrying both antimicrobial resistance and virulence genes may pose a significant threat to public health. Therefore, the identification and characterization of these plasmids may facilitate a better understanding of E. coli pathogenesis and the development of new strategies against E. coli infections. Because iron uptake ability is a potential virulence trait of bacteria, we screened for E. coli conjugative plasmids able to confer both iron uptake ability and ampicillin resistance. The plasmid pEC41, which was derived from the bacteremia clinical isolate EC41, was identified. EC41, which carried the fimH27 allele, belonged to sequence type (ST) 405 and phylogroup D. According to the sequencing analyses, pEC41 was 86 kb in size, and its backbone structure was almost identical to that of another highly conjugative plasmid, pCTX-M3, in which the extended-spectrum β-lactamase gene bla_CTX–M–3 was originally identified. pEC41 carried bla_CTX–M–3 and bla_TEM–1. The ferric citrate uptake (fec) system was identified in pEC41 and was responsible for conferring iron uptake ability. The fec system contributes to the pathogenesis of EC41 in systemic infections but not in urinary tract infections (UTIs). However, this system promoted competitive fitness of a cystitis-associated clinical isolate to colonize urinary tracts. Additionally, the distribution of the fec system was related to E. coli isolates associated with human bacteremia and UTIs. In summary, the present study identified a novel conjugative plasmid, pEC41, which conferred both antimicrobial resistance and an extra iron uptake ability to E. coli. The iron uptake ability was encoded in the fec system and contributed to E. coli pathogenesis. This study is the first to show that the fec system is a virulence factor in E. coli.

Iron Therapy in Chronic Kidney Disease: Days of Future Past

Anemia affects millions of patients with chronic kidney disease (CKD) and prompt iron supplementation can lead to reductions in the required dose of erythropoiesis-stimulating agents, thereby reducing medical costs. Oral and intravenous (IV) traditional iron preparations are considered far from ideal, primarily due to gastrointestinal intolerability and the potential risk of infusion reactions, respectively. Fortunately, the emergence of novel iron replacement therapies has engendered a paradigm shift in the treatment of iron deficiency anemia in patients with CKD. For example, oral ferric citrate is an efficacious and safe phosphate binder that increases iron stores to maintain hemoglobin levels. Additional benefits include reductions in fibroblast growth factor 23 levels and the activation of 1,25 dihydroxyvitamin D. The new-generation IV iron preparations ferumoxytol, iron isomaltoside 1000, and ferric carboxymaltose are characterized by a reduced risk of infusion reactions and are clinically well tolerated as a rapid high-dose infusion. In patients undergoing hemodialysis (HD), ferric pyrophosphate citrate (FPC) administered through dialysate enables the replacement of ongoing uremic and HD-related iron loss. FPC transports iron directly to transferrin, bypassing the reticuloendothelial system and avoiding iron sequestration. Moreover, this paper summarizes recent advancements of hypoxia-inducible factor prolyl hydroxylase inhibitors and future perspectives in renal anemia management.

State-of-the-Art Management of Hyperphosphatemia in Patients With CKD: An NKF-KDOQI Controversies Perspective

Phosphate binders are among the most common medications prescribed to patients with kidney failure receiving dialysis and are often used in advanced chronic kidney disease (CKD). In patients with CKD glomerular filtration rate category 3a (G3a) or worse, including those with kidney failure who are receiving dialysis, clinical practice guidelines suggest "lowering elevated phosphate levels towards the normal range" with possible strategies including dietary phosphate restriction or use of binders. Additionally, guidelines suggest restricting the use of oral elemental calcium often contained in phosphate binders. Nutrition guidelines in CKD suggest<800-1,000mg of calcium daily, whereas CKD bone and mineral disorder guidelines do not provide clear targets, but<1,500mg in maintenance dialysis patients has been previously recommended. Many different classes of phosphate binders are now available and clinical trials have not definitively demonstrated the superiority of any class of phosphate binders over another with regard to clinical outcomes. Use of phosphate binders contributes substantially to patients' pill burden and out-of-pocket costs, and many have side effects. This has led to uncertainty regarding the use and best choice of phosphate binders for patients with CKD or kidney failure. In this controversies perspective, we discuss the evidence base around binder use in CKD and kidney failure with a focus on comparisons of available binders.

Comparative Gut Microbiome Differences between Ferric Citrate and Calcium Carbonate Phosphate Binders in Patients with End-Stage Kidney Disease

Gut dysbiosis in patients with chronic kidney disease (CKD) may induce chronic inflammation and increase morbidity. Phosphate-binding agents, generally used in patients with CKD, may potentially change the composition of the gut microbiota. This study aimed to compare the microbiota composition in hemodialysis patients treated with ferric citrate or calcium carbonate. The stool microbiota was investigated in hemodialysis patients treated with ferric citrate (n = 8) and calcium carbonate (n = 46) using 16S rRNA gene amplicon sequencing profiling using linear discriminant analysis of effect size. Further predictive functional profiling of microbial communities was obtained with Tax4Fun in R. Hemodialysis patients treated with calcium carbonate had a significantly reduced microbial species diversity (Shannon index and Simpson index) and an increased microbial alteration ratio compared with patients treated with ferric citrate. A distinct microbial community structure was found in patients treated with ferric citrate, with an increased abundance of the Bacteroidetes phylum and a decreased abundance of the phylum Firmicutes. Members of the order Lactobacillales were enriched in patients treated with calcium carbonate, whereas taxa of the genera Ruminococcaceae UCG-004, Flavonifractor, and Cronobacter were enriched in patients treated with ferric citrate phosphate binder. In conclusion, Ferric citrate therapy results in a more diverse microbiome community compared to calcium carbonate therapy in hemodialysis patients with phosphate binder treatment. The gut microbiome reflects the phosphate binder choice in hemodialysis patients, further affecting the physiological environment in the gastrointestinal tract.

The effects of feeding ferric citrate on ruminal bacteria, methanogenic archaea and methane production in growing beef steers

Methane produced by cattle is one of the contributors of anthropogenic greenhouse gas. Methods to lessen methane emissions from cattle have been met with varying success; thus establishing consistent methods for decreasing methane production are imperative. Ferric iron may possibly act to decrease methane by acting as an alternative electron acceptor. The objective of this study was to assess the effect of ferric citrate on the rumen bacterial and archaeal communities and its impact on methane production. In this study, eight steers were used in a repeated Latin square design with 0, 250, 500 or 750 mg Fe/kg DM of ferric iron (as ferric citrate) in four different periods. Each period consisted of a 16 day adaptation period and 5 day sampling period. During each sampling period, methane production was measured, and rumen content was collected for bacterial and archaeal community analyses. Normally distributed data were analysed using a mixed model ANOVA using the GLIMMIX procedure of SAS, and non-normally distributed data were analysed in the same manner following ranking. Ferric citrate did not have any effect on bacterial community composition, methanogenic archaea nor methane production (P>0.05). Ferric citrate may not be a viable option to observe a ruminal response for decreases in enteric methane production.

Iron kinetics following treatment with sucroferric oxyhydroxide or ferric citrate in healthy rats and models of anaemia, iron overload or inflammation

Background

The iron-based phosphate binders, sucroferric oxyhydroxide (SFOH) and ferric citrate (FC), effectively lower serum phosphorus in clinical studies, but gastrointestinal iron absorption from these agents appears to differ. We compared iron uptake and tissue accumulation during treatment with SFOH or FC using experimental rat models.

Methods

Iron uptake was evaluated during an 8-h period following oral administration of SFOH, FC, ferrous sulphate (oral iron supplement) or control (methylcellulose vehicle) in rat models of anaemia, iron overload and inflammation. A 13-week study evaluated the effects of SFOH and FC on iron accumulation in different organs.

Results

In the pharmacokinetic experiments, there was a minimal increase in serum iron with SFOH versus control during the 8-h post-treatment period in the iron overload and inflammation rat models, whereas a moderate increase was observed in the anaemia model. Significantly greater increases (P < 0.05) in serum iron were observed with FC versus SFOH in the rat models of anaemia and inflammation. In the 13-week iron accumulation study, total liver iron content was significantly higher in rats receiving FC versus SFOH (P < 0.01), whereas liver iron content did not differ between rats in the SFOH and control groups.

Conclusions

Iron uptake was higher from FC versus SFOH following a single dose in anaemia, iron overload and inflammation rat models and 13 weeks of treatment in normal rats. These observations likely relate to different physicochemical properties of SFOH and FC and suggest distinct mechanisms of iron absorption from these two phosphate binders.

Effect of Ferric Citrate versus Ferrous Sulfate on Iron and Phosphate Parameters in Patients with Iron Deficiency and CKD: A Randomized Trial

BACKGROUND AND OBJECTIVES

Ferric citrate is an oral medication approved for treatment of iron deficiency anemia in patients with CKD not requiring dialysis. The relative efficacy of ferric citrate versus ferrous sulfate in treating iron deficiency in patients with CKD is unclear.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We randomized 60 adults with moderate to severe CKD (eGFR 15-45 ml/min per 1.73 m2) and iron deficiency (transferrin saturation [TSAT] ≤30% and ferritin ≤300 ng/ml) to ferric citrate (2 g three times a day with meals, n=30) or ferrous sulfate (325 mg three times a day, n=30) for 12 weeks. Primary outcomes were change in TSAT and ferritin from baseline to 12 weeks. Secondary outcomes were change in hemoglobin, fibroblast growth factor 23 (FGF23), and hepcidin.

RESULTS

Baseline characteristics were well balanced between study arms. There was a greater increase in TSAT (between-group difference in mean change, 8%; 95% confidence interval [95% CI], 1 to 15; P=0.02) and ferritin (between-group difference in mean change, 37 ng/ml; 95% CI, 10 to 64; P=0.009) from baseline to 12 weeks in participants randomized to ferric citrate as compared with ferrous sulfate. Similarly, as compared with ferrous sulfate, treatment with ferric citrate resulted in a greater increase in hepcidin from baseline to 12 weeks (between-group difference, 69 pg/ml; 95% CI, 8 to 130). There were no between-group differences in mean change for hemoglobin (0.3 g/dl; 95% CI, -0.2 to 0.8), intact FGF23 (-29 pg/ml; 95% CI, -59 to 0.1), or C-terminal FGF23 (61 RU/ml; 95% CI, -181 to 58). The incidence of adverse events did not differ between treatment arms.

CONCLUSIONS

As compared with ferrous sulfate, treatment with ferric citrate for 12 weeks resulted in a greater mean increase in TSAT and ferritin concentrations in individuals with moderate to severe CKD and iron deficiency.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Impact of Ferric Citrate vs Ferrous Sulfate on Iron Parameters and Hemoglobin in Individuals With Moderate to Severe Chronic Kidney Disease (CKD) With Iron Deficiency, NCT02888171.

Route of intestinal absorption and tissue distribution of iron contained in the novel phosphate binder ferric citrate

BACKGROUND

Anemia of chronic kidney disease (CKD) is, in part, caused by hepcidin-mediated impaired iron absorption. However, phosphate binder, ferric citrate (FC) overcomes the CKD-induced impairment of iron absorption and increases serum iron, transferrin saturation, and iron stores and reduces erythropoietin requirements in CKD/ESRD patients. The mechanism and sites of intestinal absorption of iron contained in FC were explored here.

METHODS

Eight-week old rats were randomized to sham-operated or 5/6 nephrectomized (CKD) groups and fed either regular rat chow or rat chow containing 4% FC for 6 weeks. They were then euthanized, and tissues were processed for histological and biochemical analysis using Prussian blue staining, Western blot analysis to quantify intestinal epithelial tight junction proteins and real-time PCR to measure Fatty Acid receptors 2 (FFA2) and 3 (FFA3) expressions.

RESULTS

CKD rats exhibited hypertension, anemia, azotemia, and hyperphosphatemia. FC-treated CKD rats showed significant reductions in blood pressure, serum urea, phosphate and creatinine levels and higher serum iron and blood hemoglobin levels. This was associated with marked increase in iron content of the epithelial and subepithelial wall of the descending colon and modest iron deposits in the proximal tubular epithelial cells of their remnant kidneys. No significant difference was found in hepatic tissue iron content between untreated and FC-treated CKD or control groups. Distal colon's epithelial tight Junction proteins, Occludin, JAM-1 and ZO-1 were markedly reduced in the CKD groups. The FFA2 expression in the jejunum and FFA3 expression in the distal colon were significantly reduced in the CKD rats and markedly increased with FC administration.

CONCLUSION

Iron contained in the phosphate binder, FC, is absorbed by the distal colon of the CKD animals via disrupted colonic epithelial barrier and upregulation of short chain fatty acid transporters.

Ferric citrate in the management of hyperphosphataemia and iron deficiency anaemia: A meta-analysis in patients with chronic kidney disease

AIMS

Phosphate-lowering effects of ferric citrate were reported in several clinical trials, but mostly in small-scale studies. The aim of this meta-analysis was to investigate the efficacy and safety of ferric citrate in controlling hyperphosphataemia and iron-deficiency anaemia in chronic kidney disease (CKD) patients.

METHODS

PubMed, Embase and Cochrane Library were searched for clinical trials that enrolled CKD patients receiving ferric citrate for hyperphosphataemia. Two investigators performed systematic literature search to identify eligible studies, evaluated risk of bias and extracted relevant data.

RESULTS

Sixteen studies were included in the meta-analysis. Phosphate-lowering effects of ferric citrate were greater compared to no active treatment (standardized mean difference [SMD] = -1.15; P < 0.001) and comparable to other phosphate binders (SMD = 0.03; P = 0.61). Calcium concentrations post ferric citrate treatment did not differ compared to no active treatment (SMD = 0.15; P = 0.21) but were significantly lower compared to other phosphate binders (SMD = -0.14; P = 0.01). These led to significant reductions in calcium-phosphorus product with ferric citrate versus no active control (SMD = -1.02; P < 0.001) but no difference versus active control (SMD = -0.01; P = 0.93). Intact parathyroid hormone showed no substantial between-group difference in both comparison against no active and active controls. Ferric citrate improved iron stores and anaemia parameters, but increased risk of diarrhoea, abdominal pain and discoloured faeces.

CONCLUSION

Ferric citrate was effective in lowering phosphorus and phosphorus-calcium product versus no active treatment and had comparable effects versus other phosphate binders. Calcium levels were significantly lower with ferric citrate than with other phosphate-lowering treatment. Ferric citrate had additive effects on iron repletion and anaemia control and was associated with mostly gastrointestinal side effects.

Conventional and novel impacts of ferric citrate on iron deficiency anemia and phosphorus metabolism in rats

Ferric citrate is an oral iron-based phosphate binder, being known to affect iron status and improve iron deficiency anemia (IDA) in chronic kidney disease (CKD) patients. We examined whether oral administration of ferric citrate could change iron status and improve anemia without affecting phosphorus metabolism in iron deficiency anemia rats. In Normal rat study, normal rats were fed a diet containing 0.3 or 3% ferric citrate for 11 days for setting the dose and administration period of ferric citrate. The effects of ferric citrate on iron status- and phosphorus metabolism-related parameters were evaluated using blood and urine samples. Next, an iron deficiency anemia was induced by feeding iron-depleted diet in rats. After 7 days of starting the iron-depleted diet, 0.3% ferric citrate was administered for 7 days by dietary admixture. Iron status- and phosphorus metabolism-related parameters were evaluated with blood and urine samples. In Normal rat study, 3% ferric citrate treatment increased serum iron level and transferrin saturation (TSAT), and decreased serum phosphorus level, intact fibroblast growth factor 23 (iFGF23) level, and urinary phosphorus excretion, but 0.3% ferric citrate treatment showed no effects. On the other hand, in Iron deficiency anemia rat study, 0.3% ferric citrate treatment increased iron status-related parameters and improved anemia, but did not show any apparent changes in phosphorus metabolism-related parameters. In conclusion, ferric citrate could have hematopoietic effects without affecting phosphorus metabolism, and could be a potential option for the treatment of IDA in patients without CKD.

Effect of ferric citrate on serum phosphate and fibroblast growth factor 23 among patients with nondialysis-dependent chronic kidney disease: path analyses

Background

Among patients with nondialysis-dependent chronic kidney disease (NDD-CKD) and iron-deficiency anemia (IDA), ferric citrate increases hemoglobin and iron parameters and reduces serum phosphate and fibroblast growth factor 23 (FGF23), a key phosphate-regulating hormone. We conducted post hoc analyses of a phase 3 trial to explore associations between iron replacement, serum phosphate changes and FGF23 regulation.

Methods

We employed multivariable regression and longitudinal mixed-effects models to identify and confirm, respectively, whether baseline demographic and laboratory variables were associated with ferric citrate-induced changes in serum phosphate or FGF23 concentrations. We employed path analyses to determine whether changes in FGF23 concentrations were mediated via changes in serum phosphate and/or transferrin saturation (TSAT).

Results

We analyzed a total of 117 and 115 ferric citrate-treated and placebo-treated patients, respectively. At 16 weeks, ferric citrate significantly reduced serum phosphate versus placebo (P = 0.006) only among patients with elevated baseline serum phosphate (≥4.5 mg/dL) and did not reduce serum phosphate among patients with baseline serum phosphate within the population reference range. Ferric citrate reduced intact FGF23 and C-terminal FGF23 partially via changes in TSAT (for C-terminal FGF23) and serum phosphate (for intact FGF23) and partially via unknown/unmeasured mechanisms.

Conclusions

Ferric citrate reduced serum FGF23 concentrations (partially via effects on serum phosphate and iron balance) and did not reduce serum phosphate among patients with baseline serum phosphate concentrations within the population reference range.

Iron overload resulting from the chronic oral administration of ferric citrate induces parkinsonism phenotypes in middle-aged mice

Iron homeostasis is critical for maintaining normal brain physiological functions, and its mis-regulation can cause neurotoxicity and play a part in the development of many neurodegenerative disorders. The high incidence of iron deficiency makes iron supplementation a trend, and ferric citrate is a commonly used iron supplement. In this study, we found that the chronic oral administration of ferric citrate (2.5 mg/day and 10 mg/day) for 16 weeks selectively induced iron accumulation in the corpus striatum (CPu), substantia nigra (SN) and hippocampus, which typically caused parkinsonism phenotypes in middle-aged mice. Histopathological analysis showed that apoptosis- and oxidative stress-mediated neurodegeneration and dopaminergic neuronal loss occurred in the brain, and behavioral tests showed that defects in the locomotor and cognitive functions of these mice developed. Our research provides a new perspective for ferric citrate as a food additive or in clinical applications and suggests a new potential approach to develop animal models for Parkinson's disease (PD).

A Pilot Randomized Trial of Ferric Citrate Coordination Complex for the Treatment of Advanced CKD

BACKGROUND

Researchers have yet to determine the optimal care of patients with advanced CKD. Evidence suggests that anemia and CKD-related disordered mineral metabolism (including abnormalities in phosphate and fibroblast growth factor 23 [FGF23]) contribute to adverse outcomes in this population.

METHODS

To investigate whether fixed-dose ferric citrate coordination complex favorably affects multiple biochemical parameters in patients with advanced CKD, we randomly assigned 203 patients with eGFR≤20 ml/min per 1.73 m² 2:1 to receive a fixed dose of ferric citrate coordination complex (two tablets per meal, 210 mg ferric iron per tablet) or usual care for 9 months or until 3 months after starting dialysis. No single biochemical end point was designated as primary; sample size was determined empirically.

RESULTS

The two groups had generally similar baseline characteristics, although diabetes and peripheral vascular disease were more common in the usual-care group. Ferric citrate coordination complex significantly increased hemoglobin, transferrin saturation, and serum ferritin, and it significantly reduced serum phosphate and intact FGF23 (P<0.001 for all). Of the 133 patients randomized to ferric citrate coordination complex, 31 (23%) initiated dialysis during the study period, as did 32 of 66 (48%) patients randomized to usual care (P=0.001). Compared with usual care, ferric citrate coordination complex treatment resulted in significantly fewer annualized hospital admissions, fewer days in hospital, and a lower incidence of the composite end point of death, provision of dialysis, or transplantation (P=0.002).

CONCLUSIONS

The beneficial effects of fixed-dose ferric citrate coordination complex on biochemical parameters, as well as the exploratory results regarding the composite end point and hospitalization, suggest that fixed-dose ferric citrate coordination complex has an excellent safety profile in an unselected population with advanced CKD and merits further study.

Structural characterization of polysaccharide-coated iron oxide nanoparticles produced by Staphylococcus warneri, isolated from a thermal spring

The biocompatible-coated iron oxide nanoparticles (IONs) have attracted a great interest because of their various applications in biological science and medicine. In most cases, the toxic effect of naked iron oxide nanoparticles is completely cleared by adding a biocompatible coating, such as polysaccharides, polyethylene glycol (PEG), or biosynthesis of biocompatible-coated IONs using microorganisms such as bacteria. In the present study, polysaccharide-coated iron oxide nanoparticles were produced by a strain of Staphylococcus warneri isolated from a thermal spring. For identification of the isolated bacterium, 16S rRNA gene sequencing was done. Characterization of the nanoparticles was performed for the first time, using transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), X-ray crystallography (XRD), Fourier-transform infrared (FTIR) spectroscopy, vibrating sample magnetometer (VSM), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results indicated that the spherical iron oxide nanoparticles were coated by a polysaccharide (13.6%), which provided a large negative charge of -91 mV and very low saturation magnetization of around 0.28 emu/g. The result of MTT assay on MOLT-4 cell lines showed that the percentage of viability was between 95.6% and 68.9% in the 10-100 µM of nanoparticle concentrations with a high IC ₅₀ value, which makes it appropriate for biomedical applications such as cancer therapy.

Characterization of biogenic Fe (III)-binding exopolysaccharide nanoparticles produced by Ralstonia sp. SK03

A new technological approach to nanoparticle synthesis is using microorganisms, such as bacteria, which have the ability to synthesize nontoxic nanoparticles with high biocompatibility. In addition, bacteria have strict control over size, structure, shape, and dimension of produced nanoparticles. In the present work, Fe (III)-binding exopolysaccharide (Fe-EPS) nanoparticles were biosynthesized by Ralstonia pickettii sp. SK03, a bacterium isolated from a mineral spring. 16S rRNA gene sequencing and biochemical tests were done for identification of the isolated bacterium. For the first time, critical biological and physicochemical properties of this iron oxide nanoparticle were characterized using Fourier Transform Infrared (FTIR) Spectroscopy, Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM), Dynamic Light Scattering (DLS), Thermogravimetric analysis (TGA), X-ray crystallography (XRD), Atomic absorption spectroscopy (AAS), and cell viability assays (MTT assay). The characterization results showed that Fe-EPS nanoparticles were composed of spherical ferrihydrite nanoparticles (with a size range of 1.2-2 nm), trapped in a polysaccharide matrix. The TGA analysis demonstrated that Fe-EPS nanoparticles contained ∼25.2% polysaccharide. Therefore, this polysaccharide matrix showed a very low magnetic saturation value (0.25 emu/g) and a large negative charge of -93.8 mV. In addition, treatment of hepatocarcinoma cell line (Hep-G2) with 1-500 µg/mL concentrations of Fe-EPS nanoparticles caused 40% increase in the cell viability, which indicated that the biosynthesized nanoparticles were nontoxic and biocompatible. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018 © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1167-1176, 2018.

Postgenomics Characterization of an Essential Genetic Determinant of Mammary Pathogenic Escherichia coli

Escherichia coli are major bacterial pathogens causing bovine mastitis, a disease of great economic impact on dairy production worldwide. This work aimed to study the virulence determinants of mammary pathogenic E. coli (MPEC). By whole-genome sequencing analysis of 40 MPEC and 22 environmental (“dairy-farm” E. coli [DFEC]) strains, we found that only the fec locus (fecIRABCDE) for ferric dicitrate uptake was present in the core genome of MPEC and that it was absent in DFEC genomes (P < 0.05). Expression of the FecA receptor in the outer membrane was shown to be citrate dependent by mass spectrometry. FecA was overexpressed when bacteria were grown in milk. Transcription of the fecA gene and of the inner membrane transport component fecB gene was upregulated in bacteria recovered from experimental intramammary infection. The presence of the fec system was shown to affect the ability of E. coli to grow in milk. While the rate of growth in milk of fec-positive (fec⁺) DFEC was similar to that of MPEC, it was significantly lower in DFEC lacking fec. Furthermore, deletion of fec reduced the rate of growth in milk of MPEC strain P4, whereas fec-transformed non-mammary gland-pathogenic DFEC strain K71 gained the phenotype of the level of growth in milk observed in MPEC. The role of fec in E. coli intramammary pathogenicity was investigated in vivo in cows, with results showing that an MPEC P4 mutant lacking fec lost its ability to induce mastitis, whereas the fec⁺ DFEC K71 mutant was able to trigger intramammary inflammation. For the first time, a single molecular locus was shown to be crucial in MPEC pathogenicity.

Bovine mastitis is the major infectious disease in dairy cows and the leading cause of economic loss to the global dairy industry, directly contributing to the price of dairy products on supermarket shelves and the financial hardships suffered by dairy farmers. Mastitis is also the leading reason for the use of antibiotics in dairy farms. Good farm management practices in many countries have dramatically reduced the incidence of contagious mastitis; however, the problems associated with the incidence of environmental mastitis caused by bacteria such as Escherichia coli have proven intractable. E. coli bacteria cause acute mastitis, which affects the health and welfare of cows and in extreme cases may be fatal. Here we show for the first time that the pathogenicity of E. coli causing mastitis in cows is highly dependent on the fecIRABCDE ferric citrate uptake system that allows the bacterium to capture iron from citrate. The Fec system is highly expressed during infection in the bovine udder and is ubiquitous in and necessary for the E. coli bacteria that cause mammary infections in cattle. These results have far-reaching implications, raising the possibility that mastitis may be controllable by targeting this system.

Ferric citrate and ferric EDTA but not ferrous sulfate drive amphiregulin-mediated activation of the MAP kinase ERK in gut epithelial cancer cells

Ferric chelates may be used as oral iron supplements or phosphate binders but both ferric citrate and ferric EDTA have been shown to promote tumor burden in murine models of colon cancer. Here we studied their effects on cancer cell growth, at typical supplemental iron levels encountered in the gastrointestinal tract (0.01-0.2 mM). Caco-2 and/or Hutu-80 cells were exposed to these forms of chelated iron or to ferrous sulfate and outcomes were assessed using cell proliferation assays, proteome profiler arrays, western blot, and ELISA. Ferric EDTA and ferric citrate increased cellular levels of the onco-protein amphiregulin and its receptor (EGFr) which in turn stimulated the activation of the MAP kinase ERK. Simultaneously, the expression of the negative Wnt regulator, DKK-1, increased suggesting that cell proliferation through the Wnt pathway may be less pronounced in the presence of ferric EDTA and ferric citrate, unlike for ferrous sulfate. Moreover, ferrous sulfate did not increase levels of cellular amphiregulin or EGFr. We conclude that specific iron compounds affect cell signaling differently and some may increase the risk of colon cancer advancement in an amphiregulin-dependent fashion. Further scrutiny of safe oral iron use is merited.

Biosynthesis of xanthangum‐coated INPs by using Xanthomonas campestris

Synthesis of iron nanoparticles (INPs) with a biocompatible coating usually is a multistep process which requires harsh, special and protected reaction conditions. In the current experiment, the authors used Xanthomonas campestris cells to develop a facile method for fabrication of biocompatible INPs. Bacterial cells were supplied with ferric citrate as an iron precursor. Transmission electron microscopy micrographs exhibited that xanthan gum‐coated INPs are synthesised and deposited on the surface of X. campestris cells and produced nanoparticles were 20–80 nm in diameter with 41.7 nm mean particle size. Xanthan gum coating with about 7 nm thickness formed a clear hollow around each nanoparticle. According to thermogravimetric analysis, the coating was about 13.4% of the total INPs weight. Prepared particles had a zeta potential of −114 mv which is an ideal surface charge to make particles colloidally stable in aqueous matrixes. Xanthan gum‐coated INPs were non‐crystalline with low saturation magnetisation value of about 0.26 emu/g.

Safety and efficacy of ferric citrate in phosphate reduction and iron supplementation in patients with chronic kidney disease

Ferric citrate has been reported to have the potential to reduce phosphate and increase iron availability in patients with chronic kidney disease. In the present study, we evaluated its safety and efficacy in phosphate reduction and iron supplementation in chronic kidney disease stage 3-5 requiring dialysis patients. We systematically searched for clinical trials published in PubMed, Medline, and Cochrane databases. Only randomized controlled trials on the effects of ferric citrate in chronic kidney disease stage 3–5 requiring dialysis patients were selected. The primary outcomes were changes in serum phosphate, calcium, and anemia-related parameters. The secondary outcomes were the adverse effects of ferric citrate. Nine studies providing data on 1755 patients were included in the meta-analysis. Ferric citrate significantly reduced serum phosphate compared with placebo (mean difference, –1.39; 95% confidence interval, –2.12 to –0.66) and had a non-inferior effect compared with active treatment. Furthermore, ferric citrate significantly improved hemoglobin, transferrin saturation and ferritin. Adverse effects of constipation did not differ significantly between ferric citrate and placebo or active treatment. This review provides evidence that ferric citrate effectively alleviates hyperphosphatemia and iron deficiency in patients with chronic kidney disease stage 3–5 requiring dialysis patients. However, the included studies did not have cardiovascular complications or mortality information and could not assess whether ferric citrate affected the risk of all-cause death or cardiovascular complications in patients with chronic kidney disease. Further studies are required to assess whether the long-term use of ferric citrate can reduce the risk of cardiovascular events and all-cause mortality.

Adherence rates to ferric citrate as compared to active control in patients with end stage kidney disease on dialysis

INTRODUCTION

Oral phosphate binders are the main stay of treatment of hyperphosphatemia. Adherence rates to ferric citrate, a recently approved phosphate binder, are unknown.

METHODS

We conducted a post-hoc analysis to evaluate whether adherence rates were different for ferric citrate vs. active control in 412 subjects with end stage kidney disease (ESKD) who were randomized to ferric citrate vs. active control (sevelamer carbonate and/or calcium acetate). Adherence was defined as percent of actual number of pills taken to total number of pills prescribed.

FINDINGS

There were no significant differences in baseline characteristics including gender, race/ethnicity, and age between the ferric citrate and active control groups. Baseline phosphorus, calcium, and parathyroid hormone levels were similar. Mean (SD) adherence was 81.4% (17.4) and 81.7% (15.9) in the ferric citrate and active control groups, respectively (P = 0.88). Adherence remained similar between both groups after adjusting for gender, race/ethnicity, age, cardiovascular disease (CVD), and diabetic nephropathy (mean [95% CI]: 81.4% [78.2, 84.6] and 81.5% [77.7, 85.2] for ferric citrate and active control, respectively). Gender, race/ethnicity, age, and diagnosis of diabetic nephropathy did not influence adherence to the prescribed phosphate binder. Subjects with CVD had lower adherence rates to phosphate binder; this was significant only in the active control group.

DISCUSSION

Adherence rates to the phosphate binder, ferric citrate, were similar to adherence rates to active control. Similar adherence rates to ferric citrate are notable since tolerance to active control was an entry criteria and the study was open label. Gender, race/ethnicity, nor age influenced adherence.

Ferric Citrate in Patients With Chronic Kidney Disease

Ferric citrate (FC) is an iron-containing phosphate binder that has been shown to effectively decrease serum phosphate, increase hemoglobin, and replete iron stores in patients with chronic kidney disease. Intestinal absorption of iron from FC results in increases in serum iron, ferritin, and transferrin saturation, effects that occur over 12 to 24 weeks and subsequently appear to plateau. As a result, use of erythropoiesis-stimulating agents and intravenous iron is reduced significantly and in clinical trials in patients receiving hemodialysis, the majority of subjects were able to discontinue intravenous iron use completely. One-year safety data have indicated that FC-treated subjects have reduced rates of hospitalization and reduced serious adverse events related to gastrointestinal, infectious, and cardiovascular causes, although the mechanism for this finding is unclear. The large doses of oral iron administered and lack of precise information on relative absorption over time or on the potential effect of FC on intestinal epithelial function should prompt continued clinical investigation. Although not yet approved for use in the United States for patients with non-dialysis-dependent chronic kidney disease, FC is a welcome addition to the available treatment options for decreasing phosphate concentrations. The multifaceted favorable effects on anemia and phosphate in combination with the erythropoiesis-stimulating agent and intravenous iron-sparing data support the use of FC as a first-line treatment option when phosphate-decreasing therapy is indicated.

New Options for Iron Supplementation in Maintenance Hemodialysis Patients

End-stage renal disease results in anemia caused by shortened erythrocyte survival, erythropoietin deficiency, hepcidin-mediated impairment of intestinal absorption and iron release, recurrent blood loss, and impaired responsiveness to erythropoiesis-stimulating agents (ESAs). Iron malabsorption renders oral iron products generally ineffective, and intravenous (IV) iron supplementation is required in most patients receiving maintenance hemodialysis (HD). IV iron is administered at doses far exceeding normal intestinal iron absorption. Moreover, by bypassing physiologic safeguards, indiscriminate use of IV iron overwhelms transferrin, imposing stress on the reticuloendothelial system that can have long-term adverse consequences. Unlike conventional oral iron preparations, ferric citrate has recently been shown to be effective in increasing serum ferritin, hemoglobin, and transferrin saturation values while significantly reducing IV iron and ESA requirements in patients treated with HD. Ferric pyrophosphate citrate is a novel iron salt delivered by dialysate; by directly reaching transferrin, its obviates the need for storing administered iron and increases transferrin saturation without increasing serum ferritin levels. Ferric pyrophosphate citrate trials have demonstrated effective iron delivery and stable hemoglobin levels with significant reductions in ESA and IV iron requirements. To date, the long-term safety of using these routes of iron administration in patients receiving HD has not been compared to IV iron and therefore awaits future investigations.

Iron-based phosphate binders--a new element in management of hyperphosphatemia

INTRODUCTION

Management of serum phosphorus in patients with chronic kidney disease remains a significant clinical challenge. A pivotal component of the clinical approach to maintaining serum phosphorus concentrations towards the normal range is the use of phosphate binding agents in addition to comprehensive dietary counseling. The available agents work similarly by capitalizing on a cation within the agent to bind negatively charged phosphorus, forming an insoluble complex and reducing ingested phosphorus absorption. Despite several effective options for phosphate binder therapies, patient adherence remains an issue, mainly due to adverse effect profiles and large daily pill burdens.

AREAS COVERED

Two new iron-based phosphate binder therapies have recently become available in the United States, sucroferric oxyhydroxide and ferric citrate. These agents have both been shown to effectively reduce serum phosphorus comparably to widely used calcium-based binders and sevelamer salts.

EXPERT OPINION

The two new iron-based binders differ substantially with regard to phosphate binding chemistry and iron absorption profiles. Their place in therapy is still evolving and the impact of pill burden, gastrointestinal adverse effect profiles, potential cost reduction of anemia therapies and physiologic effects of long-term iron exposure need to be further evaluated.

Ferric Citrate Reduces Intravenous Iron and Erythropoiesis-Stimulating Agent Use in ESRD

Ferric citrate (FC) is a phosphate binder with shown efficacy and additional effects on iron stores and use of intravenous (iv) iron and erythropoiesis-stimulating agents (ESAs). We provide detailed analyses of changes in iron/hematologic parameters and iv iron/ESA use at time points throughout the active control period of a phase 3 international randomized clinical trial. In all, 441 subjects were randomized (292 to FC and 149 to sevelamer carbonate and/or calcium acetate [active control (AC)]) and followed for 52 weeks. Subjects on FC had increased ferritin and transferrin saturation (TSAT) levels compared with subjects on AC by week 12 (change in ferritin, 114.1±29.35 ng/ml; P<0.001; change in TSAT, 8.62%±1.57%; P<0.001). Change in TSAT plateaued at this point, whereas change in ferritin increased through week 24, remaining relatively stable thereafter. Subjects on FC needed less iv iron compared with subjects on AC over 52 weeks (median [interquartile range] dose=12.9 [1.0-28.9] versus 26.8 [13.4-47.6] mg/wk; P<0.001), and the percentage of subjects not requiring iv iron was higher with FC (P<0.001). Cumulative ESA over 52 weeks was lower with FC than AC (median [interquartile range] dose=5303 [2023-9695] versus 6954 [2664-12,375] units/wk; P=0.04). Overall, 90.3% of subjects on FC and 89.3% of subjects on AC experienced adverse events. In conclusion, treatment with FC as a phosphate binder results in increased iron parameters apparent after 12 weeks and reduces iv iron and ESA use while maintaining hemoglobin over 52 weeks, with a safety profile similar to that of available binders.

Managing hyperphosphatemia in patients with chronic kidney disease on dialysis with ferric citrate: latest evidence and clinical usefulness

Ferric citrate is a novel phosphate binder that allows the simultaneous treatment of hyperphosphatemia and iron deficiency in patients being treated for end-stage renal disease with hemodialysis (HD). Multiple clinical trials in HD patients have uniformly and consistently demonstrated the efficacy of the drug in controlling hyperphosphatemia with a good safety profile, leading the US Food and Drug Administration in 2014 to approve its use for that indication. A concurrent beneficial effect, while using ferric citrate as a phosphate binder, is its salutary effect in HD patients with iron deficiency being treated with an erythropoietin-stimulating agent (ESA) in restoring iron that becomes available for reversing chronic kidney disease (CKD)-related anemia. Ferric citrate has also been shown in several studies to diminish the need for intravenous iron treatment and to reduce the requirement for ESA. Ferric citrate is thus a preferred phosphate binder that helps resolve CKD-related mineral bone disease and iron-deficiency anemia.

The Phosphate Binder Ferric Citrate and Mineral Metabolism and Inflammatory Markers in Maintenance Dialysis Patients: Results From Prespecified Analyses of a Randomized Clinical Trial

BACKGROUND

Phosphate binders are the cornerstone of hyperphosphatemia management in dialysis patients. Ferric citrate is an iron-based oral phosphate binder that effectively lowers serum phosphorus levels.

STUDY DESIGN

52-week, open-label, phase 3, randomized, controlled trial for safety-profile assessment.

SETTING & PARTICIPANTS

Maintenance dialysis patients with serum phosphorus levels ≥6.0 mg/dL after washout of prior phosphate binders.

INTERVENTION

2:1 randomization to ferric citrate or active control (sevelamer carbonate and/or calcium acetate).

OUTCOMES

Changes in mineral bone disease, protein-energy wasting/inflammation, and occurrence of adverse events after 1 year.

MEASUREMENTS

Serum calcium, intact parathyroid hormone, phosphorus, aluminum, white blood cell count, percentage of lymphocytes, serum urea nitrogen, and bicarbonate.

RESULTS

There were 292 participants randomly assigned to ferric citrate, and 149, to active control. Groups were well matched. For mean changes from baseline, phosphorus levels decreased similarly in the ferric citrate and active control groups (-2.04±1.99 [SD] vs -2.18±2.25 mg/dL, respectively; P=0.9); serum calcium levels increased similarly in the ferric citrate and active control groups (0.22±0.90 vs 0.31±0.95 mg/dL; P=0.2). Hypercalcemia occurred in 4 participants receiving calcium acetate. Parathyroid hormone levels decreased similarly in the ferric citrate and active control groups (-167.1±399.8 vs -152.7±392.1 pg/mL; P=0.8). Serum albumin, bicarbonate, serum urea nitrogen, white blood cell count and percentage of lymphocytes, and aluminum values were similar between ferric citrate and active control. Total and low-density lipoprotein cholesterol levels were lower in participants receiving sevelamer than those receiving ferric citrate and calcium acetate. Fewer participants randomly assigned to ferric citrate had serious adverse events compared with active control.

LIMITATIONS

Open-label study, few peritoneal dialysis patients.

CONCLUSIONS

Ferric citrate was associated with similar phosphorus control compared to active control, with similar effects on markers of bone and mineral metabolism in dialysis patients. There was no evidence of protein-energy wasting/inflammation or aluminum toxicity, and fewer participants randomly assigned to ferric citrate had serious adverse events. Ferric citrate is an effective phosphate binder with a safety profile comparable to sevelamer and calcium acetate.

Phosphorus binding with ferric citrate is associated with fewer hospitalizations and reduced hospitalization costs

BACKGROUND

Ferric citrate (FC) is a new phosphorus binder shown to increase serum iron stores while reducing intravenous iron and erythropoiesis-stimulating agent usage. Such reductions could lower hospitalization rates and associated costs.

METHODS

Hospitalizations during a Phase III trial were compared between FC and active control (AC). Hospitalization costs were estimated using the 2013 US Renal Data System Annual Data Report.

RESULTS

34.6% of FC patients were hospitalized at least once versus 45.6% of the AC group (risk reduction 24.2%; p = 0.02). There were 181 unique hospitalizations in the FC group versus 239 in the AC group, for a difference of 58 hospitalizations. Total potential savings was US$ 867,622 in hospitalization costs in the FC group. If the hospitalization reduction in our study was applied to the general end-stage renal disease population, this could translate into a savings of US$ 3002/patient/year.

CONCLUSIONS

Patients receiving FC experienced fewer hospitalizations with the potential for significant savings.

A randomized trial of JTT-751 versus sevelamer hydrochloride in patients on hemodialysis

BACKGROUND

JTT-751 is a novel phosphate binder containing ferric citrate as the active ingredient.

METHODS

In this Phase 3, multicenter, randomized, open-label, parallel-group study, we compared the efficacy and safety of JTT-751 and sevelamer hydrochloride in patients undergoing hemodialysis. A total of 230 patients with a serum phosphate ≥1.97 and <3.23 mmol/L were randomized to JTT-751 (dose adjusted between 1.5 and 6.0 g/day) or sevelamer hydrochloride (dose adjusted between 3.0 and 9.0 g/day) for 12 weeks. The primary outcome was change in serum phosphate from baseline to end of treatment. Secondary outcomes included the changes in corrected serum calcium and intact parathyroid hormone (PTH). The changes in ferritin, transferrin saturation and erythropoiesis-stimulating agent dose were additional outcomes.

RESULTS

Changes in serum phosphate at the end of treatment were -0.82 mmol/L in the JTT-751 group and -0.78 mmol/L in the sevelamer group, establishing non-inferiority of JTT-751 compared with sevelamer (least squares mean, -0.03 mmol/L; 95% confidence interval, -0.13 to 0.07 mmol/L). Corrected serum calcium increased and PTH decreased from baseline within both groups; changes between groups were similar. Gastrointestinal disorders were the most common adverse events in both groups; the incidence of diarrhea was higher in the JTT-751 group, while constipation occurred frequently in the sevelamer group. Treatment with JTT-751 resulted in significant relative increases in serum ferritin and transferrin saturation.

CONCLUSIONS

Efficacy and safety of JTT-751 was comparable to sevelamer in patients on hemodialysis with hyperphosphatemia. Differential adverse effects were observed; biochemical markers of iron status increased in patients treated with JTT-751.

TRIAL REGISTRATION NUMBER

CTI-111433 (The Japan Pharmaceutical Information Center at: http//www.clinicaltrials.jp). Date of registration: 7 March 2011.