The safety and tolerability of ferric citrate as a phosphate binder in dialysis patients

Efficacy of oral ferric citrate hydrate treatment for anemia caused by niraparib: a case report

BACKGROUND

Maintenance therapy using poly(adenosine diphosphate-ribose)polymerase inhibitors may have adverse events, including hematological toxicity, and may limit therapeutic potential in patients with cancer. Niraparib-induced anemia negatively impacts one's quality of life. Its amelioration by ferrous iron (for example, sodium ferrous citrate), folic acid, or vitamin B12 has not been supported. Oral ferric citrate hydrate increases circulating levels of iron and hepatic iron accumulation, improving renal anemia in patients with kidney failure receiving hemodialysis. The uptake of ferric iron is considered to be much higher than that of ferrous iron.

CASE PRESENTATION

The admitted patient was a 57-year-old Japanese woman with stage IIIB ovarian cancer who underwent primary debulking surgery and standard carboplatin-paclitaxel chemotherapy combined with bevacizumab, followed by niraparib (200 mg/day) maintenance therapy. The patient started oral SFC (100 mg/day) to treat niraparib-related anemia. However, she required two units of packed red blood cell transfusions three times within 3 months after starting niraparib treatment. The patient was diagnosed with niraparib-related anemia. The blood test results after 1 month from the start of niraparib treatment were as follows: red blood cells, 211 × 10⁴/μL; hemoglobin, 7.0 g/dL; hematocrit, 20.8%; reticulocyte, 0.2%; platelet count, 18.0 × 10⁴/μL. She was switched to oral ferric citrate hydrate with a dose of 500 mg per day and resumed niraparib treatment. She did not experience grade 3 niraparib-related hematological toxicity and achieved blood transfusion independence.

CONCLUSIONS

Ferric citrate hydrate may be a safe, effective, and well-tolerated oral drug for treating patients with niraparib-related anemia.

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.

Mineral Bone Disorders in Kidney Disease Patients: The Ever-Current Topic

Chronic kidney disease (CKD) is a complex and multifactorial disease, and one of the most prevalent worldwide. Chronic kidney disease–mineral bone disorders (CKD–MBD) with biochemical and hormonal alterations are part of the complications associated with the progression of CKD. Pathophysiology of CKD–MBD focused on abnormalities in serum levels of several biomarkers (such as FGF-23, klotho, phosphate, calcium, vitamin D, and PTH) which are discussed in this review. We therefore examine the prognostic association between CKD–MBD and the increased risk for cardiovascular events, mortality, and CKD progression to end-stage kidney disease (ESKD). Lastly, we present specific treatments acting on CKD to prevent and treat the complications associated with secondary hyperparathyroidism (SHPT): control of hyperphosphatemia (with dietary restriction, intestinal phosphate binders, and adequate dialysis), the use of calcimimetic agents, vitamin D, and analogues, and the use of bisphosphonates or denosumab in patients with osteoporosis.

Iron Overload Resulting from the Chronic Oral Administration of Ferric Citrate Impairs Intestinal Immune and Barrier in Mice

Ferric citrate (FC) is an iron-containing phosphate binder used as a food additive for iron supplementation. To explore the potential effect of ferric citrate on intestinal epithelial function, in the present study, we administered the mice orally for 16 weeks with different doses of iron citrate (2.5 mg/day (1.25%), 5 mg/day (2.5%), and 10 mg/day (5.0%)). We found that the iron levels of serum and tissue significantly increased, which caused the body to be in an iron overload state; meanwhile, the villus height, the ratio of villus height to crypt depth, and the number of intraepithelial lymphocytes and goblet cells in jejunum all decreased. Iron overload upregulated the pro-inflammatory cytokines (IL-1β, IL-2, IL-6, TNF-ɑ), while downregulated the anti-inflammatory cytokines (IL-4, IL-10) and sIgA. Moreover, iron overload increased serum D-lactate (D-LA) levels and decreased tight junction proteins (claudin-1, occludin, and ZO-1), MUC-2, and TFF3. In addition, iron overload upregulated the content of MDA and protein carbonyl, while downregulated the activity and content of T-AOC, GSH-PX, SOD, CAT, and GSH. To sum up, the present results showed that long-term oral administration of FC resulted in iron overload, which consequently impaired intestinal immune and barrier function in mice. Meanwhile, the effect on intestinal damage may be highly related to the increase of oxidative stress in the jejunum.

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.

Efficacy and safety of PT20, an iron-based phosphate binder, for the treatment of hyperphosphataemia: a randomized, double-blind, placebo-controlled, dose-ranging, Phase IIb study in patients with haemodialysis-dependent chronic kidney disease

Background

Hyperphosphataemia is a common complication of chronic kidney disease (CKD). PT20 (ferric iron oxide adipate) is an investigational molecule engineered to offer enhanced phosphate-binding properties relative to other phosphate binders.

Methods

In this double-blind, parallel-group, placebo-controlled, dose-ranging study (ClinicalTrials.gov identifier NCT02151643), the efficacy and safety of 28 days of oral PT20 treatment were evaluated in patients with dialysis-dependent CKD. Participants were randomly assigned in an 8:8:8:13:13 ratio to receive PT20 (400, 800, 1600 or 3200 mg) or placebo three times daily.

Results

Among 153 participants, 129 completed treatment [7 discontinued because of adverse events (AEs), 2 because of hyperphosphataemia and 15 for other reasons]. PT20 treatment for 28 days resulted in a statistically significant and dose-dependent reduction in serum phosphate concentration. There were no statistically significant effects of PT20 treatment on changes in haemoglobin or ferritin concentrations or transferrin saturation between Days 1 and 29. The incidence of treatment-emergent AEs was broadly similar across the PT20 and placebo groups (42–59% versus 44%). The most common PT20 treatment-related AEs were gastrointestinal, primarily diarrhoea (13–18%) and discoloured faeces (3–23%). No serious AEs were considered to be related to study treatment. There were no clinically significant changes in laboratory results reflecting acid/base status or increases in ferritin that could indicate the absorption of components of PT20.

Conclusions

In this first study investigating the efficacy and safety of PT20 in patients with hyperphosphataemia and dialysis-dependent CKD, PT20 significantly lowered serum phosphate concentrations and was generally well tolerated.

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.

Mechanism of Action and Clinical Attributes of Auryxia® (Ferric Citrate)

Chronic kidney disease (CKD) is a major cause of morbidity and premature mortality and represents a significant global public health issue. Underlying this burden are the many complications of CKD, including mineral and bone disorders, anemia, and accelerated cardiovascular disease. Hyperphosphatemia and elevated levels of fibroblast growth factor 23 (FGF23) have been identified as key independent risk factors for the adverse cardiovascular outcomes that frequently occur in patients with CKD. Auryxia^® (ferric citrate; Keryx Biopharmaceuticals, Inc., Boston, MA, USA) is an iron-based compound with distinctive chemical characteristics and a mechanism of action that render it dually effective as a therapy in patients with CKD; it has been approved as a phosphate binder for the control of serum phosphate levels in adult CKD patients treated with dialysis and as an iron replacement product for the treatment of iron deficiency anemia in adult CKD patients not treated with dialysis. This review focuses on Auryxia, its mechanism of action, and the clinical attributes that differentiate it from other, non-pharmaceutical-grade, commercially available forms of ferric citrate and from other commonly used phosphate binder and iron supplement therapies for patients with CKD. Consistent with the chemistry and mechanism of action of Auryxia, multiple clinical studies have demonstrated its efficacy in both lowering serum phosphate levels and improving iron parameters in patients with CKD. Levels of FGF23 decrease significantly with Auryxia treatment, but the effects associated with the cardiovascular system remain to be evaluated in longer-term studies.

Novel Oral Iron Therapies for Iron Deficiency Anemia in Chronic Kidney Disease

Iron deficiency anemia (IDA) is a frequent complication of chronic kidney disease (CKD) and is associated with adverse outcomes in these patients. Patients with CKD and IDA remain largely undertreated. Conventional oral iron agents are insufficiently effective due to poor absorption and cause gastrointestinal side effects; thus, novel oral iron preparations are needed. This article covers current treatment guidelines for patients with anemia and CKD and clinical trial data for iron-repletion agents currently in use, as well as for novel oral iron therapies in development. Ferric citrate, a novel oral iron-repletion agent approved for patients with non-dialysis-dependent CKD and IDA, demonstrated improvements in hemoglobin levels and iron parameters, with good tolerability in patients with non-dialysis-dependent CKD. When used as a phosphate binder, ferric citrate also improves hemoglobin and iron parameters in dialysis-dependent CKD, but additional trials are needed to evaluate its efficacy as an iron-repletion agent in this setting. Other novel oral iron preparations in development for IDA in patients with CKD include ferric maltol, which is approved in Europe and the United States for IDA in adult patients, and sucrosomial iron, which has been evaluated in IDA associated with CKD and several other clinical settings.

Iron-based phosphate binders: a paradigm shift in the treatment of hyperphosphatemic anemic CKD patients?

The partial correction of anemia and the normalization of phosphate and blood pressure are the mainstay of treatment of patients with chronic kidney disease (CKD). Available anti-hypertensive drugs, erythropoiesis stimulating agents (ESAs) and iron supplements have resolved quite satisfactorily the goal of controlling hypertension and partially correcting anemia. Unfortunately, the treatment of hyperphosphatemia is still far from resolved. Phosphate binders have poor tolerability and/or limited efficacy, leading to the prescription of many tablets that achieve only a mild-to-moderate effect. Moreover, increased consumption of tablets is associated with increased low tolerability, thus jeopardizing patient compliance and, in turn, the efficacy of phosphate binding. Compared to calcium-free binders, the cheaper calcium salts increase the risk of hypercalcemia, calciphylaxis and vascular calcification and possibly all-cause mortality. Calcium-free phosphate binders decrease serum phosphate levels without increasing the serum calcium concentration. The higher phosphate-binding efficacy of lanthanum carbonate compared to sevelamer should be balanced against its lack of pleiotropic effects on lipid metabolism and inflammation and the accumulation in bones. New iron-based phosphate binders are available. In addition to their phosphate binding capacity, they could also be useful to treat anemia. Iron citrate is seeking for such an indication because its iron absorption is significant. This could be of clinical importance, particularly in CKD patients not on dialysis, obviating the need for extra oral iron administration and possibly favoring compliance. In conclusion, the use of iron-based phosphate binders with significant iron absorption properties could represent a novel paradigm for correcting anemia and hyperphosphatemia in CKD patients.

Net Budgetary Impact of Ferric Citrate as a First-Line Phosphate Binder for the Treatment of Hyperphosphatemia: A Markov Microsimulation Model

Ferric citrate (FC) has demonstrated efficacy as a phosphate binder and reduces the requirements for erythropoiesis-stimulating agents (ESAs) and intravenous (IV) iron in dialysis patients. We developed a net budgetary impact model to evaluate FC vs. other phosphate binders from the vantage of a large dialysis provider. We used a Markov microsimulation model to simulate mutually referential longitudinal effects between serum phosphate and phosphate binder dose; categories of these defined health states. Health states probabilistically determined treatment attendance and utilization of ESA and IV iron. We derived model inputs from a retrospective analysis of incident phosphate binder users from a large dialysis organization (January 2011-June 2013) and incorporated treatment effects of FC from a phase III trial. The model was run over a 1-year time horizon. We considered fixed costs of providing dialysis; costs of administering ESA and IV iron; and payment rates for dialysis, ESAs, and IV iron. In the base-case model, FC had a net budgetary impact (savings) of +US$213,223/year per 100 patients treated vs. standard of care. One-way sensitivity analyses showed a net budgetary impact of up to +US$316,296/year per 100 patients treated when higher hemoglobin levels observed with FC translated into a 30% additional ESA dose reduction, and up to +US$223,281/year per 100 patients treated when effects on missed treatment rates were varied. Two-way sensitivity analyses in which acquisition costs for ESA and IV iron were varied showed a net budgetary impact of +US$104,840 to +US$213,223/year per 100 patients treated. FC as a first-line phosphate binder would likely yield substantive savings vs. standard of care under current reimbursement.

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.

Vascular calcification: When should we interfere in chronic kidney disease patients and how?

Chronic kidney disease (CKD) patients are endangered with the highest mortality rate compared to other chronic diseases. Cardiovascular events account for up to 60% of the fatalities. Cardiovascular calcifications affect most of the CKD patients. Most of this calcification is related to disturbed renal phosphate handling. Fibroblast growth factor 23 and klotho deficiency were incriminated in the pathogenesis of vascular calcification through different mechanisms including their effects on endothelium and arterial wall smooth muscle cells. In addition, deficient klotho gene expression, a constant feature of CKD, promotes vascular pathology and shares in progression of the CKD. The role of gut in the etio-pathogenesis of systemic inflammation and vascular calcification is a newly discovered mechanism. This review will cover the medical history, prevalence, pathogenesis, clinical relevance, different tools used to diagnose, the ideal timing to prevent or to withhold the progression of vascular calcification and the different medications and medical procedures that can help to prolong the survival of CKD patients.

We Give Too Much Intravenous Iron

Dialysis patients have absolute and functional iron deficiencies. Traditionally, oral iron preparations have been insufficient to maintain iron stores to support erythropoiesis, especially in the setting of the ubiquitous use of erythropoiesis-stimulating agents. This has led to the widespread adoption of intravenous iron protocols designed to maintain iron stores at levels that are much higher than for patients not on dialysis. These protocols are often developed by dialysis providers and may be largely independent of the treating nephrologist. Concerns about multiple risks associated with the use of intravenous iron persist. Despite this, mean ferritin levels in the United States have risen, partly due to more intravenous iron use and partly due to reduced erythropoiesis-stimulating agent use. Questions about the relationship of intravenous iron to infection, cardiac, and hepatobiliary risks remain. The failure of oral iron preparations to maintain iron stores continues to prompt the use of intravenous iron. Recently, studies with oral ferric citrate as a phosphate binder have shown improved iron stores and maintenance of hemoglobin, and studies with soluble ferric pyrophosphate added to dialysate have shown both maintenance of iron stores and hemoglobin. With new iron options that affect iron stores in dialysis patients, the use of intravenous iron and its potential risks may wane.

Patient-Reported Factors Associated With Poor Phosphorus Control in a Maintenance Hemodialysis Population

OBJECTIVE

The purpose of this study was to determine the influence of patient-reported medication adherence and phosphorus-related knowledge on phosphorus control and pharmacy-reported adherence to phosphorus binding medication among patients on maintenance hemodialysis.

DESIGN

Retrospective, cross-sectional cohort study.

SUBJECTS

Seventy-nine hemodialysis patients (mean age 64.2 years, SD = 14 years; 46.8% female) in a stand-alone hemodialysis unit within an integrated learning healthcare system. Ten percent (10%) of subjects were Caucasian, 42% Latino, 19% African American, and 29% Asian. Forty-eight percent had diabetes; 72% had BMI ≥ 30. Inclusion criteria included the provision of survey data and having medication refill data available in the pharmacy system. 77.2% had mean phosphorus levels ≤ 5.5 mg/dL; 22.8% had mean phosphorus levels > 5.5 mg/dL.

INTERVENTION

Subjects were administered the 8-item Morisky Medication Adherence Scale (MMAS-8) and also reported on their phosphorus-related knowledge.

MAIN OUTCOME MEASURE

Phosphorus levels within an adequate range.

RESULTS

The mean serum phosphorus level was 4.96 mg/dL (SD = 1.21). In the well-controlled group, mean phosphorus was 4.44 mg/dL (SD = 0.76). In the poorly controlled group, mean phosphorus was 6.69 mg/dL (SD = 0.74). A total of 61% of patients reported at least some unintentional medication nonadherence, and 48% reported intentional medication nonadherence. Phosphorus-specific knowledge was low, with just under half of patients reporting that they could not name two high-phosphorus foods or identify a phosphorus-related health risk. Phosphorus binder-related nonadherence was substantially higher in the uncontrolled than the controlled group. Adjusting for age, individuals with poorer self-reported binder adherence were less likely to have controlled phosphorus levels (odds ratio = 0.71, P = .06).

CONCLUSION

Phosphorus-related non-adherence, but not low phosphorus-specific knowledge, was associated with poorer phosphorus control. Such findings provide important information for the development of evidence-based strategies for improving phosphorus control among patients on dialysis.

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.

Ferric Citrate, an Iron-Based Phosphate Binder, Reduces Health Care Costs in Patients on Dialysis Based on Randomized Clinical Trial Data

BACKGROUND

Patients with end-stage renal disease (ESRD) require phosphate binders for hyperphosphatemia and erythropoiesis-stimulating agents (ESAs) and intravenous (i.v.) iron for anemia. Ferric citrate (FC) is a novel, iron-based phosphate binder that increases iron stores and decreases i.v. iron and ESA usage while maintaining hemoglobin levels, and may decrease the cost of ESRD care. The study objectives were to (1) quantify differences in ESA and i.v. iron usage among ESRD patients receiving FC compared with active control (AC) (sevelamer carbonate and/or calcium acetate) on the basis of data from a 52-week phase III clinical trial and (2) standardize trial data to the general United States (US) ESRD population and calculate the potential impact of FC on ESRD cost/patient/year in the USA.

STUDY DESIGN

The study was a randomized, controlled clinical trial.

SETTING AND POPULATION

A total of 441 adult subjects with ESRD who received FC or AC for 52 weeks were included.

MODEL, PERSPECTIVE, AND TIMELINE

Differences in ESA and i.v. iron usage between the treatment groups were modeled over time using generalized linear mixed models and zero-inflated Poisson models. Trends were modeled via logarithmic curves, and utilization patterns were applied to the general dialysis population to estimate expected resource savings.

OUTCOMES

Study outcomes were costs saved/patient/year using FC versus AC (US dollars).

RESULTS

Our model suggests an annual decrease of 129,106 U of ESAs and 1960 mg of i.v. iron per patient in the second year after a switch from AC to FC. Applying 2013 Medicare pricing, this would save $1585 in ESAs and $516 in i.v. iron: a total of $2101/patient/year; these savings would be expected to double for managed care plans.

LIMITATIONS

The projections were made on 1 year of trial data.

CONCLUSIONS

Phosphate binding with FC reduces i.v. iron and ESA usage. Given the high cost burden of ESRD, our model demonstrates significant potential cost savings.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01191255) http://clinicaltrials.gov/ct2/show/NCT01191255 .

Novel iron-containing phosphate binders for treatment of hyperphosphatemia

INTRODUCTION

Hyperphosphatemia is a frequent complication of chronic kidney disease and is associated with increased mortality. Despite side effects, risk of accumulation and high costs, phosphate binders (PBs) have become the crucial cornerstone of therapy. The iron-containing PB sucroferric oxyhydroxide (SO) and ferric citrate hydrate (FCH) have entered the market and other candidates are prior market entry.

AREAS COVERED

A literature search was performed using MEDLINE and EMBASE databases to identify references on iron-containing PB with particular regard to efficacy, safety and potential benefits. Additional hand searches were conducted along with a full-text review of any citation that appeared relevant.

EXPERT OPINION

On the highly competitive market, where the 'ideal' PB is still unknown, novel substances that offer clear benefits over available drugs are desired. Although SO and FCH showed similar efficacy and safety compared to sevelamer, head-to-head studies with lanthanum carbonate are absent. Clinical 1-year data in a limited patient cohort suggested improved adherence for SO and a large randomized controlled trial showed significant reduction in hospitalizations and costs for FCH. Additional large randomized controlled trials have now to prove these possible advantages. Cost-effectiveness in comparison to other PB and the exclusion of significant harms under long-term treatment will determine the future use of both drugs.

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.

Ferric citrate

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are sent in print and are also available on-line. Monographs can be customized to meet the needs of a facility. A drug class review is now published monthly with The Formulary Monograph Service. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service, call The Formulary at 800-322-4349. The February 2015 monograph topics are netupitant/palonosetron, naltrxone SR/bupropion SR, nintedanib, pirfenidone, and ivabradine. The Safety MUE is on netupitant/palonosetron.

Iron-based phosphate binders: do they offer advantages over currently available phosphate binders?

Increased cardiovascular morbidity and mortality has been associated with the hyperphosphatemia seen in patients with end-stage chronic kidney disease (CKD). Oral phosphate binders are prescribed in these patients to prevent intestinal absorption of dietary phosphate and reduce serum phosphate. In prospective observational cohorts they have shown to decrease all-cause and cardiovascular mortality risk. Different problems have been associated with currently available phosphate binders as positive calcium balance and impaired outcomes with calcium-based phosphate binders or increased costs with non-calcium-based phosphate binders. Iron-based phosphate binders represent a new class of phosphate binders. Several iron-based phosphate binders have undergone testing in clinical trials. Ferric citrate (JTT-751) and sucroferric oxyhydroxide (PA21) are the two iron-based binders that have passed to the clinical field after being found safe and effective in decreasing serum phosphate. Iron from ferric citrate is partially absorbed compared to sucroferric oxyhydroxide. Ferric citrate usage could result in an important reduction in erythropoiesis-stimulating agent (ESA) and IV iron usage, resulting in significant cost savings. Sucroferric oxyhydroxide was effective in lowering serum phosphorus in dialysis patients with similar efficacy to sevelamer carbonate, but with lower pill burden, and better adherence. Ferric citrate may be more suited for the treatment of chronic hyperphosphatemia in CKD patients requiring iron supplements but its use may have been hampered by potential aluminum overload, as citrate facilitates its absorption; sucroferric oxyhydroxide may be more suited for hyperphosphatemic CKD patients not requiring iron supplementation, with low pill burden.

JTT-751 for treatment of patients with hyperphosphatemia on peritoneal dialysis

BACKGROUND/AIMS

JTT-751 (ferric citrate hydrate) is a novel iron-based phosphate approved in Japan for the treatment of hyperphosphatemia in dialysis and nondialysis patients with chronic kidney disease.

METHODS

In this phase 3, multicenter, open-label, dose-adjusted study, we investigated the efficacy and safety of JTT-751 in peritoneal dialysis patients. A total of 56 patients with serum phosphate ≥5.6 and <10.0 mg/dl were enrolled in the study. The dose of JTT-751 was adjusted to between 1.5 and 6.0 g/day, according to the target range of serum phosphate (3.5-5.5 mg/dl), for 12 weeks. The primary endpoint was change in serum phosphate from baseline to end of treatment. Secondary endpoints included the percentage of patients achieving target serum phosphate levels and changes in intact parathyroid hormone.

RESULTS

Serum phosphate was significantly reduced by 2.26 mg/dl (p < 0.001). The percentage of patients achieving target serum phosphate levels was 76.8%. Intact parathyroid hormone decreased significantly (p < 0.001). The most common adverse drug reactions were diarrhea and constipation. Most of the events were considered to be mild. Treatment with JTT-751 resulted in significant increases in serum ferritin and transferrin saturation (p < 0.001).

CONCLUSION

In peritoneal dialysis patients with hyperphosphatemia, 12-week treatment with JTT-751 resulted in significant reductions in serum phosphate while simultaneously increasing serum iron parameters. JTT-751 was well tolerated.

Effects and safety of iron-based phosphate binders in dialysis patients: a systematic review and meta-analysis

AIM

To assess the effects and safety of iron-based phosphate binders in adult patients receiving dialysis.

METHODS

We electronically searched MEDLINE, EMBASE, CENTRAL, and CBM for randomized controlled trials about iron-based phosphate binders in adult dialysis patients. Study quality was assessed using the criteria outlined in the Cochrane Handbook for Systematic Reviews of intervention. Meta-analysis was conducted by RevMan 5.3.

RESULTS

Eight studies with 2018 participants were eligible for our meta-analysis. Iron-based phosphate binders were superior to placebo (MD = -2.43 mg/dL, 95% CI: -3.18 to -1.68, p < 0.00001) and as efficient as sevelamer (MD = 0.04 mg/dL, 95% CI: -0.29 to 0.36, p = 0.83) in reducing serum phosphorus in dialysis patients. No significant differences were found in all adverse events (OR = 1.30, 95% CI: 0.77 to 2.20, p = 0.32) between iron-based phosphate binders and placebo. Iron-based phosphate binders were associated with significant higher serum iron (MD = 9.39 ng/mL, 95% CI 1.48 to 17.30, p = 0.02), higher serum transferring saturation (MD = 6.29%, 95% CI 2.72 to 9.87, p = 0.0006) and lower serum total iron binding capacity (MD = -23.13 µg/dL, 95% CI -35.69 to -10.58, p = 0.0003) in comparison to placebo.

CONCLUSION

Iron-based phosphate binders are as effective as sevelamer and well tolerated for hyperphosphatemia in dialysis patients. Iron-based phosphate binders appear to have a beneficial effect on renal anemia in patients receiving dialysis. Therefore, iron-based phosphate binders may represent a new treatment option for dialysis patients.

Ferric citrate spans mineral metabolism and anemia domains in ESRD: a review of efficacy and safety data

Ferric citrate (Zerenex™, Keryx Biopharmaceuticals, Inc.), a phosphate binder drug candidate, recently completed a Phase III program confirming efficacy and demonstrating safety when used to treat hyperphosphatemia in patients with end-stage renal disease. Results of these trials demonstrate that ferric citrate effectively controls serum phosphorus and is well tolerated. Additionally, these studies demonstrate that ferric citrate improves iron parameters and reduces IV iron and erythropoietin stimulating agent utilization while maintaining hemoglobin levels. These unique features may further benefit the management of end-stage renal disease-related anemia.

Ferric citrate controls phosphorus and delivers iron in patients on dialysis

Patients on dialysis require phosphorus binders to prevent hyperphosphatemia and are iron deficient. We studied ferric citrate as a phosphorus binder and iron source. In this sequential, randomized trial, 441 subjects on dialysis were randomized to ferric citrate or active control in a 52-week active control period followed by a 4-week placebo control period, in which subjects on ferric citrate who completed the active control period were rerandomized to ferric citrate or placebo. The primary analysis compared the mean change in phosphorus between ferric citrate and placebo during the placebo control period. A sequential gatekeeping strategy controlled study-wise type 1 error for serum ferritin, transferrin saturation, and intravenous iron and erythropoietin-stimulating agent usage as prespecified secondary outcomes in the active control period. Ferric citrate controlled phosphorus compared with placebo, with a mean treatment difference of -2.2±0.2 mg/dl (mean±SEM) (P<0.001). Active control period phosphorus was similar between ferric citrate and active control, with comparable safety profiles. Subjects on ferric citrate achieved higher mean iron parameters (ferritin=899±488 ng/ml [mean±SD]; transferrin saturation=39%±17%) versus subjects on active control (ferritin=628±367 ng/ml [mean±SD]; transferrin saturation=30%±12%; P<0.001 for both). Subjects on ferric citrate received less intravenous elemental iron (median=12.95 mg/wk ferric citrate; 26.88 mg/wk active control; P<0.001) and less erythropoietin-stimulating agent (median epoetin-equivalent units per week: 5306 units/wk ferric citrate; 6951 units/wk active control; P=0.04). Hemoglobin levels were statistically higher on ferric citrate. Thus, ferric citrate is an efficacious and safe phosphate binder that increases iron stores and reduces intravenous iron and erythropoietin-stimulating agent use while maintaining hemoglobin.

Effect of oral ferric citrate on serum phosphorus in hemodialysis patients: multicenter, randomized, double-blind, placebo-controlled study

BACKGROUND

Hyperphosphatemia is a common complication in dialysis patients that can be treated by oral phosphate binders. We investigated the efficacy and safety of oral ferric citrate as a phosphate binder for Taiwanese patients with end stage renal disease and with hyperphosphatemia who were undergoing hemodialysis.

METHODS

This was a prospective, double-blind, placebo-controlled, randomized trial carried out in 5 hospitals in Taiwan. Ferric citrate (4 or 6 g/day) or placebo was administered for 56 days. Serum calcium, phosphorous levels, calcium × phosphorus product, serum ferritin level, transferrin saturation, and adverse events were recorded.

RESULTS

A total of 166 patients completed the trial. The placebo group had relatively constant serum data. Serum phosphorus declined significantly in the 6 g/day group (p < 0.05 for 4 and 8 weeks) and the 4 g/day group (p < 0.05 for 4 and 8 weeks). There were similar changes in the calcium × phosphorus product. The serum ferritin level increased significantly in the 6 g/day group (p < 0.05) and the 4 g/day group (p < 0.05). There were similar changes in transferrin saturation. Most adverse events were mild to moderate and were comparable among the three groups.

CONCLUSIONS

A 56-day treatment with ferric citrate effectively controlled hyperphosphatemia and was well tolerated in maintenance hemodialysis patients. There were also moderate increases in serum ferritin and transferrin saturation.

Long-term safety and efficacy of a novel iron-containing phosphate binder, JTT-751, in patients receiving hemodialysis

OBJECTIVE

JTT-751 is a novel phosphate binder containing ferric citrate as the active ingredient. This study investigated long-term safety and efficacy of JTT-751 for hyperphosphatemia in patients receiving hemodialysis.

DESIGN AND METHODS

This was 52-week, phase 3, multicenter, open-label, dose titration, long-term study. All patients were receiving thrice-weekly hemodialysis for ≥3 months before the initiation of the study. JTT-751 was given at titrated doses between 1.5 and 6.0 g/day.

MAIN OUTCOME MEASURES

Safety endpoints were adverse events and adverse drug reactions. Efficacy outcomes were the change in serum phosphate, corrected serum calcium, and intact parathyroid hormone. Changes in ferritin, transferrin saturation, and doses of erythropoiesis-stimulating agents (ESAs) and intravenous iron formulations were additional outcomes.

RESULTS

One hundred and eighty patients were included in the trial. Dose-titrated JTT-751 decreased mean serum phosphate after administration and satisfactorily maintained serum phosphate concentrations throughout the entire duration of the 52-week trial. Mean serum phosphate concentrations were kept lower than 5.5 mg/dL from weeks 5 to 52. The most common adverse events were gastrointestinal disorders, which were mild to moderate in intensity. Serum ferritin concentrations rose to a peak around week 28 and stabilized thereafter. The mean intravenous iron dose decreased from 57.3 mg/4 weeks (weeks 0-12) to 3.6 mg/4 weeks (weeks 28-52); weekly ESA dose declined by 25% over the same time frame, while mean hemoglobin concentrations remained stable.

CONCLUSION

JTT-751 1.5-6.0 g/day controls serum phosphorus concentrations and reduces the need for ESAs and intravenous iron in patients receiving hemodialysis.

Drug-drug interactions between sucroferric oxyhydroxide and losartan, furosemide, omeprazole, digoxin and warfarin in healthy subjects

Background

The novel iron-based phosphate binder sucroferric oxyhydroxide is being investigated for the treatment of hyperphosphatemia. Patients with chronic kidney disease often have multiple comorbidities that may necessitate the daily use of several types of medication. Therefore, the potential pharmacokinetic drug–drug interactions between sucroferric oxyhydroxide and selected drugs commonly taken by dialysis patients were investigated.

Methods

Five Phase I, single-center, open-label, randomized, three-period crossover studies in healthy volunteers investigated the effect of a single dose of sucroferric oxyhydroxide 1 g (based on iron content) on the pharmacokinetics of losartan 100 mg, furosemide 40 mg, omeprazole 40 mg, digoxin 0.5 mg and warfarin 10 mg. Pharmacokinetic parameters [including area under the plasma concentration–time curve (AUC) from time 0 extrapolated to infinite time (AUC_0–∞) and from 0 to 24 h (AUC_0–24)] for these drugs were determined: alone in the presence of food; with sucroferric oxyhydroxide in the presence of food; 2 h after food and sucroferric oxyhydroxide administration.

Results

Systemic exposure based on AUC_0–∞ for all drugs, and AUC_0–24 for all drugs except omeprazole (for which AUC 0–8 h was measured), was unaffected to a clinically significant extent by the presence of sucroferric oxyhydroxide, irrespective of whether sucroferric oxyhydroxide was administered with the drug or 2 h earlier.

Conclusions

There is a low risk of drug–drug interactions between sucroferric oxyhydroxide and losartan, furosemide, digoxin and warfarin. There is also a low risk of drug–drug interaction with omeprazole (based on AUC_0–∞ values). Therefore, sucroferric oxyhydroxide may be administered concomitantly without the need to adjust the dosage regimens of these drugs.

Renal osteodystrophy in children: pathogenesis, diagnosis and treatment

PURPOSE OF REVIEW

Disturbances in calcium-phosphate homeostasis play an important role in children with chronic kidney disease, and not only cause renal osteodystrophy but also result in increased cardiovascular morbidity and mortality. This review outlines the current aspects in the pathogenesis, diagnostic approach and treatment of renal osteodystrophy.

RECENT FINDINGS

The pathogenesis of renal osteodystrophy is under strong influence of the fibroblast growth factor 23/Klotho system, which is able to enhance phosphate excretion and reduce calcitriol synthesis in the kidney. Fibroblast growth factor 23 increases tissue calcinosis and is cardiotoxic, and is independently associated with mortality. Despite improvement in diagnostic imaging (bone density measurements), determination of biomarkers, mainly parathyroid hormone, still plays a central role. New treatment options resulted in improved bone health and also a reduction in mortality was achieved in adults with calcium-free phosphate binders. Substitution of active and inactive vitamin D is important and also has a beneficial effect on proteinuria.

SUMMARY

Knowledge about the biochemical and molecular mechanisms of renal osteodystrophy is increasing dramatically and has an impact not only to bone health but also overall morbidity and mortality. This will ultimately translate into further improved diagnostic approaches and novel treatment options.

A phase III study of the efficacy and safety of a novel iron-based phosphate binder in dialysis patients

Efficacy of PA21 (sucroferric oxyhydroxide), a novel calcium-free polynuclear iron(III)-oxyhydroxide phosphate binder, was compared with that of sevelamer carbonate in an open-label, randomized, active-controlled phase III study. Seven hundred and seven hemo- and peritoneal dialysis patients with hyperphosphatemia received PA21 1.0–3.0 g per day and 348 received sevelamer 4.8–14.4 g per day for an 8-week dose titration, followed by 4 weeks without dose change, and then 12 weeks maintenance. Serum phosphorus reductions at week 12 were −0.71 mmol/l (PA21) and −0.79 mmol/l (sevelamer), demonstrating non-inferiority of, on average, three tablets of PA21 vs. eight of sevelamer. Efficacy was maintained to week 24. Non-adherence was 15.1% (PA21) vs. 21.3% (sevelamer). The percentage of patients that reported at least one treatment-emergent adverse event was 83.2% with PA21 and 76.1% with sevelamer. A higher proportion of patients withdrew owing to treatment-emergent adverse events with PA21 (15.7%) vs. sevelamer (6.6%). Mild, transient diarrhea, discolored feces, and hyperphosphatemia were more frequent with PA21; nausea and constipation were more frequent with sevelamer. After 24 weeks, 99 hemodialysis patients on PA21 were re-randomized into a 3-week superiority analysis of PA21 maintenance dose in 50 patients vs. low dose (250 mg per day (ineffective control)) in 49 patients. The PA21 maintenance dose was superior to the low dose in maintaining serum phosphorus control. Thus, PA21 was effective in lowering serum phosphorus in dialysis patients, with similar efficacy to sevelamer carbonate, a lower pill burden, and better adherence.

Ferric citrate hydrate for the treatment of hyperphosphatemia in nondialysis-dependent CKD

BACKGROUND AND OBJECTIVES

Ferric citrate hydrate is a novel iron-based phosphate binder being developed for hyperphosphatemia in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A phase 3, multicenter, randomized, double blind, placebo-controlled study investigated the efficacy and safety of ferric citrate hydrate in nondialysis-dependent patients with CKD. Starting in April of 2011, 90 CKD patients (eGFR=9.21±5.72 ml/min per 1.73 m(2)) with a serum phosphate≥5.0 mg/dl were randomized 2:1 to ferric citrate hydrate or placebo for 12 weeks. The primary end point was change in serum phosphate from baseline to the end of treatment. Secondary end points included the percentage of patients achieving target serum phosphate levels (2.5-4.5 mg/dl) and change in fibroblast growth factor-23 at the end of treatment.

RESULTS

The mean change in serum phosphate was -1.29 mg/dl (95% confidence interval, -1.63 to -0.96 mg/dl) in the ferric citrate hydrate group and 0.06 mg/dl (95% confidence interval, -0.20 to 0.31 mg/dl) in the placebo group (P<0.001 for difference between groups). The percentage of patients achieving target serum phosphate levels was 64.9% in the ferric citrate hydrate group and 6.9% in the placebo group (P<0.001). Fibroblast growth factor-23 concentrations were significantly lower in patients treated with ferric citrate hydrate versus placebo (change from baseline [median], -142.0 versus 67.0 pg/ml; P<0.001). Ferric citrate hydrate significantly increased serum iron, ferritin, and transferrin saturation compared with placebo (P=0.001 or P<0.001). Five patients discontinued active treatment because of treatment-emergent adverse events with ferric citrate hydrate treatment versus one patient with placebo. Overall, adverse drug reactions were similar in patients receiving ferric citrate hydrate or placebo, with gastrointestinal disorders occurring in 30.0% of ferric citrate hydrate patients and 26.7% of patients receiving placebo.

CONCLUSION

In patients with nondialysis-dependent CKD, 12-week treatment with ferric citrate hydrate resulted in significant reductions in serum phosphate and fibroblast growth factor-23 while simultaneously increasing serum iron parameters.

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.

Hyperparathyroidism in chronic kidney disease patients: an update on current pharmacotherapy

INTRODUCTION

Secondary hyperparathyroidism is the most common abnormalities of mineral metabolism in chronic kidney disease (CKD), which causes bone disease and vascular calcification, leading to increased risk of mortality.

AREAS COVERED

The aim of this review is to provide an overview of pharmacological therapies for secondary hyperparathyroidism, based on current understanding of the disease.

EXPERT OPINION

The initial event in the pathogenesis of secondary hyperparathyroidism is the phosphorus overload per nephron that lead to the secretion of a new phosphaturic hormone, fibroblast growth factor 23 from the bone. Such an abnormality develops very early in CKD, even without hyperphosphatemia. When hyperphosphatemia develops, phosphate binders are prescribed in many CKD patients. Non-calcium containing binders are gaining popularity because of less risk of excess calcium load; however, no specific superiority in patient-level outcomes has been fully established yet. For the direct control of parathyroid hormone secretion, cinacalcet hydrochloride has become widespread in addition to vitamin D receptor activators. As adverse events related to these therapeutic agents occur occasionally, however, and better adherence is one of the most important determinants of the benefits of the drugs, fewer adverse events as well as more potent therapeutic effects should be aimed in the development of new agents in future.

Ferric citrate hydrate, a new phosphate binder, prevents the complications of secondary hyperparathyroidism and vascular calcification

BACKGROUND/AIMS

Ferric citrate hydrate (JTT-751) is being developed as a treatment for hyperphosphatemia in chronic kidney disease patients, and shows serum phosphorus-reducing effects on hyperphosphatemia in hemodialysis patients. We examined whether JTT-751 could reduce phosphorus absorption in normal rats and prevent the progression of ectopic calcification, secondary hyperparathyroidism and bone abnormalities in chronic renal failure (CRF) rats.

METHODS

Normal rats were fed a diet containing 0.3, 1 or 3% JTT-751 for 7 days. The effects of JTT-751 on phosphorus absorption were evaluated with fecal and urinary phosphorus excretion. Next, a CRF model simulating hyperphosphatemia was induced by feeding rats a 0.75% adenine diet. After 21 days of starting the adenine diet feeding, 1 or 3% JTT-751 was administered for 35 days by dietary admixture. The serum phosphorus levels and mineral parameters were measured. Calcification in the aorta was examined biochemically and histopathologically. Hyperparathyroidism and bone abnormalities were evaluated by histopathological analysis of the parathyroid and femur, respectively.

RESULTS

In normal rats, JTT-751 increased fecal phosphorus excretion and reduced phosphorus absorption and urinary phosphorus excretion. In CRF rats, JTT-751 reduced serum phosphorus levels, the calcium-phosphorus product and calcium content in the aorta. Serum intact parathyroid hormone levels and the incidence and severity of parathyroid hyperplasia were also decreased. JTT-751 reduced femoral bone fibrosis, porosity and osteoid formation.

CONCLUSIONS

JTT-751 could bind with phosphate in the gastrointestinal tract, increase fecal phosphorus excretion and reduce phosphorus absorption. JTT-751 could prevent the progression of ectopic calcification, secondary hyperparathyroidism and bone abnormalities in rats.