The safety of achieved iron stores and their effect on IV iron and ESA use: post-hoc results from a randomized trial of ferric citrate as a phosphate binder in dialysis
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Iron stores assuring optimal efficacy/safety for erythropoiesis are unknown in the dialysis population. Using multicenter trial data, we related safety profiles, erythropoiesis-stimulating agent (ESA), and intravenous iron dosing to achieved iron stores in 441 subjects randomized 2 : 1 to ferric citrate or active control as their phosphate binder over 52 weeks. Intravenous iron was given at each site's discretion if ferritin ≤ 1,000 ng/mL and transferrin saturation ≤ 30%. Multivariable time-dependent Cox regression jointly related the primary safety outcome (composite of cardiac, infection, gastrointestinal, and hepatobiliary serious adverse events) to moving averages of ferritin and transferrin saturation over the preceding 90 days with covariate adjustment. Multivariable generalized estimating equations related elevated ESA and intravenous iron doses to trailing 90-day averages of ferritin and transferrin saturation with covariate adjustment. The adjusted hazard ratio for the safety composite per 10% increase in transferrin saturation was 0.84 (95% confidence interval 0.68 - 1.02, p = 0.08) and 1.09 (0.86 - 1.35, p = 0.48) per 400 ng/mL increase in ferritin. The adjusted hazard ratio for the safety composite was 0.50 (0.29 - 0.88, p = 0.016) for the highest transferrin saturation tertile vs. the lowest. Adjusted odds ratios for higher intravenous iron dose were lower in the highest (0.23 [0.16 - 0.35], p < 0.001) and middle transferrin saturation tertile (0.42 [0.31 - 0.57], p < 0.001) vs. lowest. Incidence of elevated ESA dose was lower in the highest transferrin saturation tertile (p = 0.01). Ferritin did not predict clinical events or ESA dose. Transferrin saturation may be a better marker than serum ferritin to judge optimal iron stores in dialysis patients. Transferrin saturations > 34% are safe and provide maximal efficacy.
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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 .

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.

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.

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.

Rationale and study design of a three-period, 58-week trial of ferric citrate as a phosphate binder in patients with ESRD on dialysis.

Chronic kidney disease associated mineral and bone disorders arise as a result of aberrant bone mineral metabolism in patients with advancing levels of renal dysfunction and end-stage renal disease. One of the cornerstones of treatment is the use of phosphate-binding agents. We describe the rationale and study design for a clinical trial to assess the safety and efficacy of ferric citrate as a phosphate binder. This trial is a three-period, international, multicenter, randomized, controlled clinical trial to assess the safety and efficacy of ferric citrate as a phosphate binder, consisting of a 2-week washout period, a 52-week safety assessment period in which subjects are randomized to ferric citrate or active control, and a 4-week efficacy assessment period in which subjects randomized to ferric citrate in the safety assessment period are randomized to ferric citrate or placebo. Eligible subjects include end-stage renal disease patients who have been treated with thrice-weekly hemodialysis or peritoneal dialysis for at least 3 months in dialysis clinics in the United States and Israel. Primary outcome measure will be the effect of ferric citrate vs. placebo on the change in serum phosphorus. Safety assessments will be performed by monitoring adverse events, concomitant medication use, and sequential blood chemistries (including iron parameters, phosphorus, and calcium). This three-period trial will assess the efficacy of ferric citrate as a phosphate binder. If proven safe and efficacious, ferric citrate will likely provide an additional phosphate binder to treat chronic kidney disease associated mineral and bone disorders.

Ferric citrate: a novel phosphate-binding agent.

Ferric citrate (KRX-0502; Keryx Biopharmaceuticals, Inc., NY, USA) is a novel phosphate-binding agent presently in Phase III clinical development. Ferric citrate dissociates in the bowel lumen releasing the ferric ion to precipitate with dietary phosphorus, which is then excreted in the stool. Studies to date have shown the agent to be efficacious and safe with only mild gastrointestinal side effects. Absorption of either component of the agent (ferric iron or citrate) has the potential to be of benefit for patients with end-stage renal disease. An ongoing Phase III trial is confirming the safety and efficacy of ferric citrate as a phosphate binder in dialysis patients.

The role of sulodexide in the treatment of diabetic nephropathy.

Diabetic nephropathy is an important cause of morbidity and mortality in patients with either type 1 or type 2 diabetes mellitus. The pathogenesis and natural history of diabetic nephropathy, characterised by a progressive decline in glomerular function, were initially described in patients with type 1 diabetes. Reports that describe the glomerulopathy and progression of renal disease in patients with type 2 diabetes suggest that the disease process is similar to that observed in patients with type 1 diabetes with diabetic nephropathy. An emerging body of evidence supports the notion that glomerular capillary wall and mesangial alterations in diabetic nephropathy involve pathobiochemical alterations of glycoproteins in these structures. Evidence in experimental animals rendered diabetic, reveal that the administration of heparin and other anionic glycoproteins can effectively prevent the biochemical alterations that promote albuminuria. Clinical reports of the use of sulodexide, a preparation of low molecular weight glycosaminoglycan polysaccharides, have shown that proteinuria is significantly diminished in patients with diabetic nephropathy, even when these patients are receiving either an ACE inhibitor or angiotensin receptor antagonist.

Pharmacokinetics and dose proportionality of extended-release metformin following administration of 1000, 1500, 2000 and 2500 mg in healthy volunteers.

The pharmacokinetics and dose-exposure relationship of an extended-release formulation of metformin (ER-metformin) was investigated in a randomized, single-dose, four-period crossover study in 24 healthy male volunteers. During each study period, subjects received a randomly assigned dose containing 1000, 1500, 2000 or 2500 mg metformin. Blood samples were drawn 0-72 h after dosing for pharmacokinetic and dose-proportionality assessment. Although several pairwise comparisons between dose groups were significant (p<0.05) with respect to dose-normalized C(max), AUC(0-72 h), and AUC( infinity ), the magnitude of the difference across the dose range was <20% for AUC(0-72 h) and AUC( infinity ), and was < or = 30% for C(max). The results indicate a consistent and predictable increase in metformin exposure with an extended-release formulation of metformin over 1000 to 2500 mg.

Pharmacokinetics of lovastatin extended-release dosage form (Lovastatin XL) in healthy volunteers.

The purpose of this study was to evaluate pharmacokinetics and dose proportionality of lovastatin extended-release dosage form (ER-lovastatin) in the dosage levels of 10, 20 and 40 mg in 9 healthy male subjects. Each subject was randomized to receive a single oral dose of ER-lovastatin either 10, 20 or 40 mg in a three-way crossover design with a washout period of 7 days between the treatments. Subjects were served dinner at approximately 5:30 PM followed by dosing at approximately 10:00 PM in each study period. Serial plasma samples were collected up to 48 h after dosing and assayed for lovastatin and its active metabolite lovastatin acid using an LC/MS/MS method. The plasma concentration-time profiles of lovastatin and its active metabolite lovastatin acid exhibited delayed- and extended-release characteristics at each dose. Mean (+/-) values for the C(max) of lovastatin were 1.04+/-0.43, 2.03+/-0.65 and 4.03+/-3.02 ng/ml for the 10, 20 and 40 mg dosage, respectively. The corresponding values for the AUC(0-48 h) of lovastatin were 14.6+/-7.8, 34.1 +/-13.7, and 53.9+/-35.6 ng h/ml. The same tendency was also found for C(max) and AUC(0-48 h) values of lovastatin acid. Results from this study demonstrated as the dose of ER-lovastatin increased from 10 to 40 mg, the C(max) and AUC(0-48 h) values of lovastatin as well as lovastatin acid appeared to increase linearly.

A multiple-dose pharmacodynamic, safety, and pharmacokinetic comparison of extended- and immediate-release formulations of lovastatin.

BACKGROUND: Because lovastatin is efficiently extracted by the liver and because its administration in divided doses is associated with increased efficacy, an extended-release (ER) formulation may have the potential for a dose-sparing advantage relative to the immediate-release (IR) formulation in the treatment of hypercholesterolemia. OBJECTIVE: This study compared the short-term pharmacodynamics, safety, and pharmacokinetics of multiple doses of lovastatin ER with those of lovastatin IR in patients with fasting low-density lipoprotein cholesterol (LDL-C) levels between 130 and 250 mg/dL and fasting triglyceride levels < 350 mg/dL. METHODS: The study had a randomized, single-blind, positive-controlled, 2-way crossover design, with a 4-week diet/placebo run-in period and two 4-week active-treatment periods. During period 1, patients received either lovastatin ER or lovastatin IR (both 40 mg OD). After 4 weeks of the initial study treatment and a 2-week washout period, patients were switched to the alternate treatment (period 2). Pharmacodynamic parameters (LDL-C, high-density lipoprotein cholesterol, total cholesterol, and triglyceride levels) were evaluated by combining data from weeks 3 and 4 of treatment. In a pharmacokinetic substudy, maximum plasma concentrations (C(max)) and area under the plasma concentration-time curve from zero to 24 hours (AUC(024)) were determined for lovastatin, lovastatin acid, and total and active inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase on days 1 and 28 of active treatment. The geometric mean ratio of AUC(0-24) (lovastatin ER/lovastatin IR) was also calculated for each of these substances. RESULTS: Of 76 patients who entered the run-in period, 26 (12 men, 14 women; mean age, 56.2 years) were randomized to receive active treatment and 24 were included in the efficacy analysis; 13 patients were included in the pharmacokinetic substudy, 12 of whom had complete pharmacokinetic data. Compared with lovastatin IR, lovastatin ER produced a 3.9% greater reduction in LDL-C (P = 0.044). Changes in other lipid parameters were not statistically significant. In the pharmacokinetic substudy, C(max) values for lovastatin, lovastatin acid, and in hibitors of HMG-CoA reductase were lower at day 28 with lovastatin ER than with lovastatin IR. The AUC(0-24) ratio for lovastatin was 1.91 (90% CI, 1.77 - 3.35), reflecting higher bioavailability of the prodrug with lovastatin ER; in contrast, the ratios for lovastatin acid and active and total inhibitors of HMG-CoA reductase were < 1. CONCLUSIONS: In this short-term study in a small number of patients, lovastatin ER 40 mg produced significantly greater LDL-C lowering than did an equal dose of lovastatin IR, with a relatively low C(max) and comparable systemic exposure to lovastatin acid and active and total inhibitors of HMG-CoA reductase. Lovastatin ER was well tolerated, with no discontinuations due to adverse events.

Comparative pharmacokinetics of lovastatin extended-release tablets and lovastatin immediate-release tablets in humans.

The pharmacokinetics of lovastatin and its active metabolite lovastatin acid was evaluated in 9 healthy subjects in a three-period crossover study following a single oral dose of lovastatin extended-release (ER) tablets and lovastatin immediate-release (IR) tablets. Participants were dosed with lovastatin IR 40 mg tablets following a standard breakfast, lovastatin ER 40 mg tablets following a standard breakfast, and lovastatin ER 40 mg tablets underfasting conditions. Serial plasma samples were collected for up to 48 hours postdose and assayed for lovastatin and lovastatin acid using a liquid chromatography/mass spectroscopy/mass spectroscopy method. Lovastatin ER tablets, unlike lovastatin IR tablets, exhibited delayed- and extended-release characteristics. The relative bioavailability, in terms of area under the curve values, of lovastatin (156%) and lovastatin acid (124%) was greater from lovastatin ER tablets as compared with lovastatin IR tablets when given with breakfast. An even greater increase in the bioavailability of lovastatin (261%) and lovastatin acid (231%) was observed when the lovastatin ER tablets were administered under fasting conditions. Thus, greater gastrointestinal tract drug absorption of lovastatin from lovastatin ER tablets was demonstrated. Ingestion of a standard breakfast prior to administration of lovastatin ER tablets decreased absorption of lovastatin by approximately 40%, relative to lovastatin ER tablets under fasting conditions.