A Randomized Trial of Tenapanor and Phosphate Binders as a Dual-Mechanism Treatment for Hyperphosphatemia in Patients on Maintenance Dialysis (AMPLIFY).

BACKGROUND: Hyperphosphatemia is associated with cardiovascular morbidity and mortality in patients receiving maintenance dialysis. It is unknown whether combining two therapies with different mechanisms of action-tenapanor, an inhibitor of paracellular phosphate absorption, and phosphate binders-is safe and effective for the management of hyperphosphatemia in patients receiving maintenance dialysis. METHODS: This double-blind phase 3 trial enrolled 236 patients undergoing maintenance dialysis with hyperphosphatemia (defined in this trial as serum phosphorus 5.5-10 mg/dl inclusive) despite receiving phosphate binder therapy (sevelamer, nonsevelamer, sevelamer plus nonsevelamer, or multiple nonsevelamer binders). These participants were randomly assigned to receive oral tenapanor 30 mg twice daily or placebo for 4 weeks. The primary efficacy end point was the change in serum phosphorus concentration from baseline to week 4. RESULTS: Of the 236 randomized patients, 235 (99.6%) were included in the full analysis set; this included 116 in the tenapanor plus binder group and 119 in the placebo plus binder group. A total of 228 patients (96.6%) completed the 4-week treatment period. In the full analysis set (mean age 54.5 years, 40.9% women), patients treated with tenapanor plus binder achieved a larger mean change in serum phosphorus concentration from baseline to week 4 compared with placebo plus binder (-0.84 versus -0.19 mg/dl, P<0.001). Diarrhea was the most commonly reported adverse event, resulting in study drug discontinuation in four of 119 (3.4%) and two of 116 (1.7%) patients receiving tenapanor plus binder or placebo plus binder, respectively. CONCLUSIONS: A dual-mechanism treatment using both tenapanor and phosphate binders improved control of hyperphosphatemia in patients undergoing maintenance dialysis compared with phosphate binders alone. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: AMPLIFY, NCT03824587.

Iron Deficiency in Chronic Kidney Disease: Updates on Pathophysiology, Diagnosis, and Treatment.

Anemia is a complication that affects a majority of individuals with advanced CKD. Although relative deficiency of erythropoietin production is the major driver of anemia in CKD, iron deficiency stands out among the mechanisms contributing to the impaired erythropoiesis in the setting of reduced kidney function. Iron deficiency plays a significant role in anemia in CKD. This may be due to a true paucity of iron stores (absolute iron deficiency) or a relative (functional) deficiency which prevents the use of available iron stores. Several risk factors contribute to absolute and functional iron deficiency in CKD, including blood losses, impaired iron absorption, and chronic inflammation. The traditional biomarkers used for the diagnosis of iron-deficiency anemia (IDA) in patients with CKD have limitations, leading to persistent challenges in the detection and monitoring of IDA in these patients. Here, we review the pathophysiology and available diagnostic tests for IDA in CKD, we discuss the literature that has informed the current practice guidelines for the treatment of IDA in CKD, and we summarize the available oral and intravenous (IV) iron formulations for the treatment of IDA in CKD. Two important issues are addressed, including the potential risks of a more liberal approach to iron supplementation as well as the potential risks and benefits of IV versus oral iron supplementation in patients with CKD.

Economic Burden and Health-Related Quality of Life Associated with Current Treatments for Anaemia in Patients with CKD not on Dialysis: A Systematic Review.

BACKGROUND: The cost and health-related quality of life (HRQoL) burden associated with treatments for anaemia of chronic kidney disease (CKD) is not well characterized among non-dialysis-dependent (NDD) patients. OBJECTIVE: Our objective was to review the literature on costs and HRQoL associated with current treatments for anaemia of CKD among NDD patients. METHODS: The Cochrane Library, MEDLINE, Embase, NHS EED, and NHS HTA databases were searched for original studies published in English between 1 January 2000 and 17 March 2017. The following inclusion criteria were applied: adult population; primary focus was anaemia of CKD; patients received iron supplementation, red blood cell transfusion, or erythropoiesis-stimulating agents (ESAs); and reported results on HRQoL and/or costs. Studies that included NDD patients, did not compare different treatments, and had relevant designs were retained. HRQoL and cost outcomes were summarized in a narrative synthesis. RESULTS: In total, 16 studies met the inclusion criteria: six randomized controlled trials, four prospective single-arm trials, three retrospective studies, one prospective observational study, one simulation study, and one cross-sectional survey. All included ESAs. Treatment of anaemia (compared with no treatment) was associated with HRQoL improvements in five of six studies and lower costs in four of four studies. Treatment aiming for higher haemoglobin targets (compared with lower targets) resulted in modest HRQoL improvements, higher healthcare resource utilization (HRU), and higher costs. CONCLUSIONS: In NDD patients, untreated anaemia of CKD leads to higher costs, higher HRU, and lower HRQoL compared with initiating anaemia treatment. Relative to aiming for lower haemoglobin targets with ESAs, higher targets conferred modest HRQoL improvements and were associated with higher HRU.

Economic and quality of life burden of anemia on patients with CKD on dialysis: a systematic review.

Aims: The overall cost and health-related quality of life (HRQoL) associated with current treatments for chronic kidney disease (CKD)-related anemia are not well characterized. A systematic literature review (SLR) was conducted on the costs and HRQoL associated with current treatments for CKD-related anemia among dialysis-dependent (DD) patients. Materials and methods: The authors searched the Cochrane Library, MEDLINE, EMBASE, NHS EED, and NHS HTA for English-language publications. Original studies published between January 1, 2000 and March 17, 2017 meeting the following criteria were included: adult population; study focus was CKD-related anemia; included results on patients receiving iron supplementation, red blood cell transfusion, or erythropoiesis stimulating agents (ESAs); reported results on HRQoL and/or costs. Studies which included patients with DD-CKD, did not directly compare different treatments, and had designs relevant to the objective were retained. HRQoL and cost outcomes, including healthcare resource utilization (HRU), were extracted and summarized in a narrative synthesis. Results: A total of 1,625 publications were retrieved, 15 of which met all inclusion criteria. All identified studies included ESAs as a treatment of interest. Two randomized controlled trials reported that ESA treatment improves HRQoL relative to placebo. Across eight studies comparing HRQoL of patients achieving high vs low hemoglobin (Hb) targets, aiming for higher Hb targets with ESAs generally led to modest HRQoL improvements. Two studies reported that ESA-treated patients had lower costs and HRU compared to untreated patients. One study found that aiming for higher vs lower Hb targets led to reduced HRU, while two other reported that this led to a reduction in cost-effectiveness. Limitations: Heterogeneity of study designs and outcomes; a meta-analysis could not be performed. Conclusions: ESA-treated patients undergoing dialysis incurred lower costs, lower HRU, and had better HRQoL relative to ESA-untreated patients. However, treatment to higher Hb targets led to modest HRQoL improvements compared to lower Hb targets.

Ferric citrate controls serum phosphorus in dialysis patients: retrospective data
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Ferric citrate is an approved phosphate binder for use in patients with chronic kidney disease on dialysis. Clinical trials demonstrated that ferric citrate controlled serum phosphorus levels and increased iron stores. The aim of this retrospective chart review was to evaluate real-world bone mineral and anemia parameter data from patients treated with ferric citrate. 92 adult dialysis patients taking ferric citrate (average starting dose of 6 tablets/day) for at least 6 months were included. Bone mineral, anemia, and iron biomarker levels were extracted from patient medical records before and during the first 6 months of ferric citrate treatment; 21 (23%) patients were phosphate binder naïve, and 71 (77%) patients had been on other phosphate binders. Before starting ferric citrate, 22% of patients had serum phosphorus ≤ 5.5 mg/dL, increasing to 65% of patients at 6 months of treatment (month 6). Mean (standard error of the mean (SEM)) baseline serum phosphorus was 6.55 ± 0.17 mg/dL decreasing to 5.40 ± 0.17 mg/dL at month 6. Mean (SEM) baseline hemoglobin, ferritin, and transferrin saturation were 10.6 ± 0.2 g/dL, 734 ± 65 ng/mL, and 27.1 ± 1.6%, respectively, and 11.1 ± 0.2 g/dL, 947 ± 66 ng/mL, and 37 ± 1.9%, respectively, at month 6. The serum phosphorus and anemia biomarker levels observed in this retrospective chart review were similar to those seen in clinical trials.
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Effects of Ferric Citrate in Patients with Nondialysis-Dependent CKD and Iron Deficiency Anemia.

Iron deficiency anemia is common and consequential in nondialysis-dependent CKD (NDD-CKD). Efficacy and tolerability of conventional oral iron supplements are mixed; intravenous iron administration associates with finite but important risks. We conducted a randomized double-blind clinical trial in adults with NDD-CKD and iron deficiency anemia to compare the safety and efficacy of oral ferric citrate (n=117) and placebo (n=115). The primary end point was the proportion of patients who achieved a ≥1.0 g/dl increase in hemoglobin at any time during a 16-week randomized period. Patients who completed the 16-week period could also participate in an 8-week open-label extension period. Significantly more patients randomized to ferric citrate achieved the primary end point (61 [52.1%] versus 22 [19.1%] with placebo; P<0.001). All secondary end points reached statistical significance in the ferric citrate group, including the mean relative change in hemoglobin (0.84 g/dl; 95% confidence interval, 0.58 to 1.10 g/dl; P<0.001) and the proportion of patients who achieved a sustained increase in hemoglobin (≥0.75 g/dl over any 4-week period during the randomized trial; 57 [48.7%] versus 17 [14.8%] with placebo; P<0.001). Rates of serious adverse events were similar in the ferric citrate (12.0%) and placebo groups (11.2%). Gastrointestinal disorders were the most common adverse events, with diarrhea reported in 24 (20.5%) and 19 (16.4%) and constipation in 22 (18.8%) and 15 (12.9%) patients treated with ferric citrate and placebo, respectively. Overall, in patients with NDD-CKD, we found oral ferric citrate to be a safe and efficacious treatment for iron deficiency anemia.