Difelikefalin in Black/African American Hemodialysis Patients with Moderate-to-Severe Pruritus: Post hoc Analysis of KALM-1 and KALM-2.

INTRODUCTION: Black and African American (AA) people are over-represented in the kidney failure population; therefore, the safety and efficacy of difelikefalin in Black/AA patients was evaluated. METHODS: This was a post hoc, pooled exploratory subgroup analysis of the Phase 3 KALM-1 and -2 studies. Patients undergoing hemodialysis (HD) who had moderate-to-severe chronic kidney disease-associated pruritus (CKD-aP) at enrollment were stratified into self-reported Black/AA or White subgroups. Patients were randomized (1:1) to receive intravenous (IV) difelikefalin 0.5 µg/kg or placebo for 12 weeks. Difelikefalin efficacy was assessed with validated patient-reported outcome questionnaires: 24-h Worst Itch Numerical Rating Scale (WI-NRS), 5-D itch, and Skindex­10. RESULTS: There were 249 (29.3%) patients from the KALM studies that self-identified as Black/AA (n = 135 difelikefalin; n = 114 placebo). Clinically meaningful (≥3-point) reduction in WI-NRS score was achieved by 47.9% of Black/AA patients with difelikefalin versus 24.6% with placebo (p < 0.001). More Black/AA patients achieved a ≥5-point 5-D itch total improvement (54.9% vs. 35.7%; p = 0.013) and a ≥15-point Skindex-10 score improvement with difelikefalin versus placebo (49.0% vs. 28.9%; p = 0.006) compared with White patients. Incidence of treatment-emergent adverse events (TEAEs) was higher for Black/AA patients (difelikefalin: 78.5%; placebo: 70.8%) versus White patients (difelikefalin: 64.8%; placebo: 61.8%). CONCLUSION: In this post hoc analysis, difelikefalin was efficacious in the Black/AA population and had an acceptable safety profile.

Clinical impact of suboptimal RAASi therapy following an episode of hyperkalemia.

BACKGROUND: Hyperkalemia (HK) is a barrier to optimization of renin-angiotensin-aldosterone system inhibitor (RAASi) therapy in heart failure (HF) and chronic kidney disease (CKD). We investigated cardiorenal risk associated with changes in RAASi regimen after an episode of HK in patients with HF and/or CKD. METHODS: This observational study utilized data from hospital records, claims, and health registers from the US (Optum's de-identified Market Clarity Data) and Japan (Medical Data Vision). Included patients had an index episode of HK between July 2019 and September 2021 (US), or May 2020 and September 2021 (Japan), with prior diagnosis of HF or CKD (stage 3 or 4), and RAASi use. Risk of a cardiorenal composite outcome (HF emergency visit, HF hospitalization, or progression to end-stage kidney disease) was determined in patients who discontinued RAASi, down-titrated their dose by > 25%, or maintained or up-titrated their dose following the HK episode. RESULTS: A total of 15,488 and 6020 patients were included from the US and Japan, respectively. Prior to the episode of HK, 59% (US) and 27% (Japan) of patients had achieved > 50% target RAASi dose. Following the episode of HK, 33% (US) and 32% (Japan) of patients did not fill a new RAASi prescription. Risk of the cardiorenal outcome at 6 months was higher in patients who discontinued or down-titrated versus maintained or up-titrated RAASi treatment both in the US (17.5, 18.3, and 10.6%; p <  0.001) and in Japan (19.7, 20.0, and 15.1%; p <  0.001). CONCLUSION: HK-related RAASi discontinuation or down-titration was associated with higher risk of cardiorenal events versus maintained or up-titrated RAASi.

Roxadustat Versus Epoetin Alfa for Treating Anemia in Patients with Chronic Kidney Disease on Dialysis: Results from the Randomized Phase 3 ROCKIES Study.

BACKGROUND: Concerns regarding cardiovascular safety with current treatments for anemia in patients with dialysis-dependent (DD)-CKD have encouraged the development of alternatives. Roxadustat, an oral hypoxia-inducible factor prolyl hydroxylase inhibitor, stimulates erythropoiesis by increasing endogenous erythropoietin and iron availability. METHODS: In this open-label phase 3 study, patients with DD-CKD and anemia were randomized 1:1 to oral roxadustat three times weekly or parenteral epoetin alfa per local clinic practice. Initial roxadustat dose depended on erythropoiesis-stimulating agent dose at screening for patients already on them and was weight-based for those not on them. The primary efficacy end point was mean hemoglobin change from baseline averaged over weeks 28‒52 for roxadustat versus epoetin alfa, regardless of rescue therapy use, tested for noninferiority (margin, -0.75 g/dl). Adverse events (AEs) were assessed. RESULTS: Among 2133 patients randomized (n=1068 roxadustat, n=1065 epoetin alfa), mean age was 54.0 years, and 89.1% and 10.8% were on hemodialysis and peritoneal dialysis, respectively. Mean (95% confidence interval) hemoglobin change from baseline was 0.77 (0.69 to 0.85) g/dl with roxadustat and 0.68 (0.60 to 0.76) g/dl with epoetin alfa, demonstrating noninferiority (least squares mean difference [95% CI], 0.09 [0.01 to 0.18]; P<0.001). The proportion of patients experiencing ≥1 AE and ≥1 serious AE was 85.0% and 57.6% with roxadustat and 84.5% and 57.5% with epoetin alfa, respectively. CONCLUSIONS: Roxadustat effectively increased hemoglobin in patients with DD-CKD, with an AE profile comparable to epoetin alfa. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Safety and Efficacy Study of Roxadustat to Treat Anemia in Patients With Chronic Kidney Disease, on Dialysis. CLINICALTRIALS: gov Identifier: NCT02174731.

Potassium responses to sodium zirconium cyclosilicate in hyperkalemic hemodialysis patients: post-hoc analysis of DIALIZE.

BACKGROUND: Sodium zirconium cyclosilicate (SZC) is an effective and well-tolerated treatment for hyperkalemia in maintenance hemodialysis patients. In post-hoc analyses of the phase 3b DIALIZE study, we examined the spectrum of potassium responses to SZC. METHODS: Post-hoc analyses with SZC and placebo included: the number of long interdialytic interval (LIDI) visits during the 4-week evaluation period where patients attained pre-dialysis serum potassium (sK+) concentrations of 4.0-5.0 and 4.0-5.5 mmol/L; potassium gradient (the difference between pre-dialysis sK+ and dialysate potassium) at days 36, 43, 50, and 57, and change from baseline to the end of treatment (EOT) using categories of potassium gradient (1 to < 2, 2 to < 3, 3 to < 4, and ≥ 4 mmol/L). RESULTS: A greater proportion of patients achieved the ranges of pre-dialysis sK+ concentration with SZC versus placebo for ≥1, ≥ 2, ≥ 3, and 4 LIDI visits over 4 weeks; 23.7 and 48.5% of patients in the SZC group achieved pre-dialysis sK+ concentrations of 4.0-5.0 and 4.0-5.5 mmol/L, respectively, at all 4 LIDI visits. Baseline mean potassium gradient was similar with SZC and placebo. At day 57, mean (standard deviation) potassium gradient was 2.78 (0.08) mmol/L with SZC and 3.52 (0.08) mmol/L with placebo; mean difference (95% confidence interval) was - 0.74 mmol/L (- 0.97 to - 0.52). A greater reduction in potassium gradient category from baseline towards lower-risk categories at EOT was observed with SZC versus placebo. CONCLUSIONS: These analyses expand our knowledge of the spectrum of potassium responses with SZC in hyperkalemic hemodialysis patients. TRIAL REGISTRATION: NCT03303521 .

Establishing a Core Outcome Set for Autosomal Dominant Polycystic Kidney Disease: Report of the Standardized Outcomes in Nephrology-Polycystic Kidney Disease (SONG-PKD) Consensus Workshop.

The omission of outcomes that are of relevance to patients, clinicians, and regulators across trials in autosomal dominant polycystic kidney disease (ADPKD) limits shared decision making. The Standardized Outcomes in Nephrology-Polycystic Kidney Disease (SONG-PKD) Initiative convened an international consensus workshop on October 25, 2018, to discuss the identification and implementation of a potential core outcome set for all ADPKD trials. This article summarizes the discussion from the workshops and the SONG-PKD core outcome set. Key stakeholders including 11 patients/caregivers and 47 health professionals (nephrologists, policy makers, industry, and researchers) attended the workshop. Four themes emerged: "Relevance of trajectory and impact of kidney function" included concerns about a patient's prognosis and uncertainty of when they may need to commence kidney replacement therapy and the lack of an early prognostic marker to inform long-term decisions; "Discerning and defining pain specific to ADPKD" highlighted the challenges in determining the origin of pain, adapting to the chronicity and repeated episodes of pain, the need to place emphasis on pain management, and to have a validated measure for pain; "Highlighting ADPKD consequences" encompassed cyst-related complications and reflected patient's knowledge because of family history and the hereditary nature of ADPKD; and "Risk for life-threatening but rare consequences" such as cerebral aneurysm meant considering both frequency and severity of the outcome. Kidney function, mortality, cardiovascular disease, and pain were established as the core outcomes for ADPKD.

Management of Hyperphosphatemia in End-Stage Renal Disease: A New Paradigm.

Bone and mineral metabolism becomes dysregulated with progression of chronic kidney disease (CKD), and increasing levels of parathyroid hormone serve as an adaptive response to maintain normal phosphorus and calcium levels. In end-stage renal disease, this response becomes maladaptive and high levels of phosphorus may occur. We summarize strategies to control hyperphosphatemia based on a systematic literature review of clinical trial and real-world observational data on phosphorus control in hemodialysis patients with CKD-mineral bone disorder (CKD-MBD). These studies suggest that current management options (diet and lifestyle changes; regular dialysis treatment; and use of phosphate binders, vitamin D, calcimimetics) have their own benefits and limitations with variable clinical outcomes. A more integrated approach to phosphorus control in dialysis patients may be necessary, incorporating measurement of multiple biomarkers of CKD-MBD pathophysiology (calcium, phosphorus, and parathyroid hormone) and correlation between diet adjustments and CKD-MBD drugs, which may facilitate improved patient management.

The Difference Between Cystatin C- and Creatinine-Based Estimated GFR and Associations With Frailty and Adverse Outcomes: A Cohort Analysis of the Systolic Blood Pressure Intervention Trial (SPRINT).

RATIONALE & OBJECTIVE: In prior research and in practice, the difference between estimated glomerular filtration rate (eGFR) calculated from cystatin C level and eGFR calculated from creatinine level has not been assessed for clinical significance and relevance. We evaluated whether these differences contain important information about frailty. STUDY DESIGN: A cohort analysis of the Systolic Blood Pressure Intervention Trial (SPRINT). SETTING & PARTICIPANTS: 9,092 hypertensive SPRINT participants who had baseline measurements of serum creatinine, cystatin C, and frailty. EXPOSURE: eGFRs calculated using CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equations (eGFRcys and eGFRcr), and eGFRDiff, calculated as eGFRcys-eGFRcr. OUTCOMES: A validated 35-item frailty index that included questionnaire data for general and physical health, limitations of activities, pain, depression, sleep, energy level, self-care, and smoking status, as well as medical history, cognitive assessment, and laboratory data. We defined frailty as frailty index score>0.21 (range, 0-1). The incidence of injurious falls, hospitalizations, cardiovascular events, and mortality was also recorded. ANALYTICAL APPROACH: We used logistic regression to model the cross-sectional association of baseline eGFRDiff with frailty among all SPRINT participants. Adjusted proportional hazards regression was used to evaluate the association of eGFRDiff with adverse outcomes and mortality. RESULTS: Mean age was 68±9 (SD) years, mean eGFRcys and eGFRcr were 73±23 and 72±20mL/min/1.73m2, and mean eGFRDiff was 0.5±15mL/min/1.73m2. In adjusted models, each 1-SD higher eGFRDiff was associated with 24% lower odds of prevalent frailty (OR, 0.76; 95% CI, 0.71-0.81), as well as with lower incidence rate of injurious falls (HR, 0.84; 95% CI, 0.77-0.92), hospitalization (HR, 0.91; 95% CI, 0.88-0.95), cardiovascular events (HR, 0.89; 95% CI, 0.81-0.97), and all-cause mortality (HR, 0.71; 95% CI, 0.63-0.82); P<0.01. LIMITATIONS: Gold-standard measure of kidney function and assessment of muscle mass were not available. CONCLUSIONS: The difference between eGFRcys and eGFRcr is associated with frailty and health status. Positive eGFRDiff is strongly associated with lower risks for longitudinal adverse outcomes and mortality, even after adjusting for chronic kidney disease stage and baseline frailty.

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

BACKGROUND: The iron-based phosphate binders, sucroferric oxyhydroxide (SFOH) and ferric citrate (FC), effectively lower serum phosphorus in clinical studies, but gastrointestinal iron absorption from these agents appears to differ. We compared iron uptake and tissue accumulation during treatment with SFOH or FC using experimental rat models. METHODS: Iron uptake was evaluated during an 8-h period following oral administration of SFOH, FC, ferrous sulphate (oral iron supplement) or control (methylcellulose vehicle) in rat models of anaemia, iron overload and inflammation. A 13-week study evaluated the effects of SFOH and FC on iron accumulation in different organs. RESULTS: In the pharmacokinetic experiments, there was a minimal increase in serum iron with SFOH versus control during the 8-h post-treatment period in the iron overload and inflammation rat models, whereas a moderate increase was observed in the anaemia model. Significantly greater increases (P < 0.05) in serum iron were observed with FC versus SFOH in the rat models of anaemia and inflammation. In the 13-week iron accumulation study, total liver iron content was significantly higher in rats receiving FC versus SFOH (P < 0.01), whereas liver iron content did not differ between rats in the SFOH and control groups. CONCLUSIONS: Iron uptake was higher from FC versus SFOH following a single dose in anaemia, iron overload and inflammation rat models and 13 weeks of treatment in normal rats. These observations likely relate to different physicochemical properties of SFOH and FC and suggest distinct mechanisms of iron absorption from these two phosphate binders.

One-year safety and efficacy of intravenous etelcalcetide in patients on hemodialysis with secondary hyperparathyroidism.

BACKGROUND: Secondary hyperparathyroidism (sHPT), a common complication of chronic kidney disease, is characterized by elevated serum parathyroid hormone (PTH). Etelcalcetide is an intravenous calcimimetic that increases sensitivity of the calcium-sensing receptor to calcium and decreases PTH secretion. This open-label extension (OLE) trial evaluated the long-term effects of etelcalcetide for sHPT treatment in patients receiving hemodialysis. METHODS: This 52-week, multicenter, single-arm OLE enrolled patients from three parent trials: two randomized, double-blind, placebo-controlled trials and one open-label, single-arm, 'switch' study from cinacalcet to etelcalcetide. The primary endpoint was to investigate the nature, frequency, severity and relation to treatment of all adverse events (AEs) reported throughout the trial. Secondary endpoints included the proportion of patients with >30% reduction from baseline in PTH and the percentage change from baseline in PTH, albumin-corrected calcium (Ca), phosphate (P) and the calcium-phosphate product (Ca × P).ClinicalTrials.gov identifier: NCT01785875; Amgen study: 20120231. RESULTS: Overall, 89.8% of the patients experienced one or more treatment-emergent AE. The most common were decreased blood Ca (43.3%), diarrhea (10.8%), vomiting (10.4%) and nausea (9.6%); symptomatic hypocalcemia occurred in 3.7% of the patients. Approximately 68% of patients achieved >30% reduction in PTH, and ∼56% achieved PTH ≤300 pg/mL. Mean percent changes from baseline ranged from -25.4% to -26.1% for PTH, -8.3% to -9.1% for Ca, -3.6% to -4.1% for P and -12.0% to -12.6% for Ca × P. CONCLUSIONS: Etelcalcetide effectively lowered PTH and its effect was sustained, while no new safety concerns emerged over a 1-year treatment period.

Arterial stiffness and kidney disease progression in the systolic blood pressure intervention trial
.

AIMS: Arterial stiffness increases with both advancing age and chronic kidney disease (CKD) and may contribute to kidney function decline, but evidence is inconsistent. We hypothesized that greater baseline arterial stiffness (assessed as pulse pressure (PP) and carotid-femoral pulse-wave velocity CFPWV)) was independently associated with kidney disease progression over the follow-up period (3.8 years) in the Systolic Blood Pressure Intervention Trial (SPRINT). MATERIALS AND METHODS: 8,815 SPRINT participants were included in the analysis of PP. 592 adults who participated in a SPRINT ancillary study that measured CFPWV were included in subgroup analyses. Cox proportional hazards analysis was used to examine the association between PP and time to kidney disease progression endpoints: (A) incident estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73m2 in non-CKD participants at baseline; (B) 50% decline in eGFR, initiation of dialysis, or transplant in those with baseline CKD. Mixed model analyses examined the association of baseline PP/CFPWV with follow-up eGFR. RESULTS AND CONCLUSION: Mean ± SD age was 68 ± 10 years, baseline PP was 62 ± 14 mmHg, and CFPWV was 10.8 ± 2.7 m/s. In the fully adjusted model, PP ≥ median was associated with an increased hazard of kidney disease progression endpoints (HR: 1.93 (1.43 - 2.61)). The association remained significant in individuals without (2.05 (1.47 - 2.87)) but not with baseline CKD (1.28 (0.55 - 2.65)). In fully adjusted models, higher baseline PP associated with eGFR decline (p < 0.0001 (all, CKD, non-CKD)), but baseline CFPWV did not. Among older adults at high risk for cardiovascular events, baseline PP was associated with kidney disease progression.

A Phase 3b, Randomized, Double-Blind, Placebo-Controlled Study of Sodium Zirconium Cyclosilicate for Reducing the Incidence of Predialysis Hyperkalemia.

BACKGROUND: Patients with ESRD have minimal renal potassium excretion and, despite hemodialysis, often have persistent predialysis hyperkalemia. The DIALIZE study (NCT03303521) evaluated sodium zirconium cyclosilicate (SZC) in the management of hyperkalemia in hemodialysis patients. METHODS: In the DIALIZE study, a double-blind, placebo-controlled, phase 3b multicenter study, we randomized adults with ESRD who were managed by three-times weekly hemodialysis and had predialysis hyperkalemia to receive placebo or SZC 5 g once daily on non-dialysis days, and titrated towards maintaining normokalemia over 4 weeks, in 5 g increments to a maximum of 15 g. The primary efficacy outcome was proportion of patients during the 4-week stable-dose evaluation period who maintained predialysis serum potassium of 4.0-5.0 mmol/L during at least three of four hemodialysis treatments after the long interdialytic interval and did not require urgent rescue therapy to reduce serum potassium. RESULTS: In total, 196 patients (mean [standard deviation (SD)] age =58.1 [13.7] years old) were randomized to sodium zirconium cyclosilicate or placebo. Of 97 patients receiving sodium zirconium cyclosilicate, 41.2% met the primary end point and were deemed treatment responders compared with 1.0% of 99 patients receiving placebo (P<0.001). Rescue therapy to reduce serum potassium during the treatment period was required by 2.1% of patients taking sodium zirconium cyclosilicate versus 5.1% taking placebo. Serious adverse events occurred in 7% and 8% of patients in sodium zirconium cyclosilicate and placebo groups, respectively. The two groups displayed comparable interdialytic weight gain. There were few episodes of hypokalemia. CONCLUSIONS: Sodium zirconium cyclosilicate is an effective and well-tolerated treatment for predialysis hyperkalemia in patients with ESRD undergoing adequate hemodialysis.

The SPRINT trial suggests that markers of tubule cell function in the urine associate with risk of subsequent acute kidney injury while injury markers elevate after the injury.

Urine markers can quantify tubular function including reabsorption (α-1 microglobulin [α1m]) and ß-2-microglobulin [ß2m]) and protein synthesis (uromodulin). Individuals with tubular dysfunction may be less able to compensate to insults than those without, despite similar estimated glomerular filtration rate (eGFR) and albuminuria. Among Systolic Blood Pressure Intervention Trial (SPRINT) participants with an eGFR under 60 ml/min/1.73m2, we measured urine markers of tubular function and injury (neutrophil gelatinase-associated lipocalin [NGAL], kidney injury molecule-1 [KIM-1], interleukin-18 [IL-18], monocyte chemoattractant protein-1, and chitinase-3-like protein [YKL-40]) at baseline. Cox models evaluated associations with subsequent acute kidney injury (AKI) risk, adjusting for clinical risk factors, baseline eGFR and albuminuria, and the tubular function and injury markers. In a random subset, we remeasured biomarkers after four years, and compared changes in biomarkers in those with and without intervening AKI. Among 2351 participants, 184 experienced AKI during 3.8 years mean follow-up. Lower uromodulin (hazard ratio per two-fold higher (0.68, 95% confidence interval [0.56, 0.83]) and higher α1m (1.20; [1.01, 1.44]) were associated with subsequent AKI, independent of eGFR and albuminuria. None of the five injury markers were associated with eventual AKI. In the random subset of 947 patients with repeated measurements, the 59 patients with intervening AKI versus without had longitudinal increases in urine NGAL, IL-19, and YKL-40 and only 1 marker of tubule function (α1m). Thus, joint evaluation of tubule function and injury provided novel insights to factors predisposing to AKI, and responses to kidney injury.

Effects of sucroferric oxyhydroxide and sevelamer carbonate on chronic kidney disease-mineral bone disorder parameters in dialysis patients.

BACKGROUND: Treatment of hyperphosphataemia is the primary goal of chronic kidney disease-mineral and bone disorder (CKD-MBD) management. This post hoc analysis of a randomized, Phase 3 study evaluated the effects of 1-year treatment with the phosphate binders sucroferric oxyhydroxide or sevelamer carbonate ('sevelamer') on CKD-MBD indices among dialysis patients with hyperphosphataemia. METHODS: After a 2- to 4-week washout from previous phosphate binders, 1059 patients were randomized 2:1 to sucroferric oxyhydroxide 1.0-3.0 g/day (n = 710) or sevelamer 2.4-14.4 g/day (n = 349) for up to 24 weeks. Eligible patients enrolled in a 28-week extension. This post hoc analysis was performed for patients who completed ≥1 year of continuous treatment (n = 549). As the treatment groups showed similar CKD-MBD outcomes, the data were pooled for this analysis. RESULTS: Phosphate-binder therapy was associated with significant and sustained 30% reductions in serum phosphorus (P < 0.001). Median intact fibroblast growth factor-23 (FGF-23) also significantly decreased (P < 0.001) by 64% over 1 year. Intact parathyroid hormone decreased significantly after 24 weeks (P < 0.001), but levels returned to near baseline values by Week 52; minimal changes in serum calcium were observed. Of the bone resorption markers evaluated, tartrate-resistant acid phosphatase 5b (TRAP5b) decreased significantly (P < 0.001), whereas CTx increased transiently but returned to baseline levels by Week 52. The bone formation markers bone-specific alkaline phosphatase and osteocalcin both increased over 1 year of treatment. CONCLUSIONS: Overall, 1 year of sucroferric oxyhydroxide or sevelamer treatment significantly reduced serum FGF-23, which has been associated with clinical benefit in patients with CKD. The trend towards increased bone formation marker levels indicates a beneficial effect on bone metabolism.

A Practical Guide for Treatment of Rapidly Progressive ADPKD with Tolvaptan.

In the past, the treatment of autosomal dominant polycystic kidney disease (ADPKD) has been limited to the management of its symptoms and complications. Recently, the US Food and Drug Administration (FDA) approved tolvaptan as the first drug treatment to slow kidney function decline in adults at risk of rapidly progressing ADPKD. Full prescribing information approved by the FDA provides helpful guidelines but does not address practical questions that are being raised by nephrologists, internists, and general practitioners taking care of patients with ADPKD, and by the patients themselves. In this review, we provide practical guidance and discuss steps that require consideration before and after prescribing tolvaptan to patients with ADPKD to ensure that this treatment is implemented safely and effectively. These steps include confirmation of diagnosis; identification of rapidly progressive disease; implementation of basic renal protective measures; counseling of patients on potential benefits and harms; exclusions to use; education of patients on aquaresis and its expected consequences; initiation, titration, and optimization of tolvaptan treatment; prevention of aquaresis-related complications; evaluation and management of liver enzyme elevations; and monitoring of treatment efficacy. Our recommendations are made on the basis of published evidence and our collective experiences during the randomized, clinical trials and open-label extension studies of tolvaptan in ADPKD.

Effects of Intensive Systolic Blood Pressure Control on Kidney and Cardiovascular Outcomes in Persons Without Kidney Disease: A Secondary Analysis of a Randomized Trial.

BACKGROUND: The public health significance of the reported higher incidence of chronic kidney disease (CKD) with intensive systolic blood pressure (SBP) lowering is unclear. OBJECTIVE: To examine the effects of intensive SBP lowering on kidney and cardiovascular outcomes and contrast its apparent beneficial and adverse effects. DESIGN: Subgroup analyses of SPRINT (Systolic Blood Pressure Intervention Trial). (ClinicalTrials.gov: NCT01206062). SETTING: Adults with high blood pressure and elevated cardiovascular risk. PARTICIPANTS: 6662 participants with a baseline estimated glomerular filtration rate (eGFR) of at least 60 mL/min/1.73 m2. INTERVENTION: Random assignment to an intensive or standard SBP goal (120 or 140 mm Hg, respectively). MEASUREMENTS: Differences in mean eGFR during follow-up (estimated with a linear mixed-effects model), prespecified incident CKD (defined as a >30% decrease in eGFR to a value <60 mL/min/1.73 m2), and a composite of all-cause death or cardiovascular event, with surveillance every 3 months. RESULTS: The difference in adjusted mean eGFR between the intensive and standard groups was -3.32 mL/min/1.73 m2 (95% CI, -3.90 to -2.74 mL/min/1.73 m2) at 6 months, was -4.50 mL/min/1.73 m2 (CI, -5.16 to -3.85 mL/min/1.73 m2) at 18 months, and remained relatively stable thereafter. An incident CKD event occurred in 3.7% of participants in the intensive group and 1.0% in the standard group at 3-year follow-up, with a hazard ratio of 3.54 (CI, 2.50 to 5.02). The corresponding percentages for the composite of death or cardiovascular event were 4.9% and 7.1% at 3-year follow-up, with a hazard ratio of 0.71 (CI, 0.59 to 0.86). LIMITATION: Long-term data were lacking. CONCLUSION: Intensive SBP lowering increased risk for incident CKD events, but this was outweighed by cardiovascular and all-cause mortality benefits. PRIMARY FUNDING SOURCE: National Institutes of Health.

Iron-related parameters in dialysis patients treated with sucroferric oxyhydroxide.

BACKGROUND: Sucroferric oxyhydroxide is a non-calcium, iron-based phosphate binder indicated for the treatment of hyperphosphataemia in adult dialysis patients. This post hoc analysis of a randomized, 24-week Phase 3 study and its 28-week extension was performed to evaluate the long-term effect of sucroferric oxyhydroxide on iron parameters. METHODS: A total of 1059 patients were randomized to sucroferric oxyhydroxide 1.0-3.0 g/day (n = 710) or sevelamer carbonate ('sevelamer') 2.4-14.4 g/day (n = 349) for up to 52 weeks. The current analysis only included patients who completed 52 weeks of continuous treatment (n = 549). Changes in iron-related parameters and anti-anaemic product use during the study were measured. RESULTS: Some changes in iron-related parameters across both treatment groups were observed during the first 24 weeks of the study, and to a lesser extent with longer-term treatment. There were small, but significantly greater increases in mean transferrin saturation (TSAT) and haemoglobin levels with sucroferric oxyhydroxide versus sevelamer during the first 24 weeks (change in TSAT: +4.6% versus +0.6%, P = 0.003; change in haemoglobin: +1.6 g/L versus -1.1 g/L, P = 0.037). Mean serum ferritin concentrations also increased from Weeks 0 to 24 with sucroferric oxyhydroxide and sevelamer (+119 ng/mL and +56.2 ng/mL respectively; no statistically significant difference between groups). In both treatment groups, ferritin concentrations increased to a greater extent in the overall study population [>70% of whom received concomitant intravenous (IV) iron], compared with the subset of patients who did not receive IV iron therapy during the study. The pattern of anti-anaemic product use was similar in both treatment groups, with a trend towards higher use of IV iron and erythropoiesis-stimulating agents with sevelamer. CONCLUSIONS: Initial increases in some iron-related parameters were observed in both treatment groups but were more pronounced with sucroferric oxyhydroxide. These differences between treatment groups with respect to changes in iron parameters are likely due to minimal iron absorption from sucroferric oxyhydroxide.

One-year efficacy and safety of the iron-based phosphate binder sucroferric oxyhydroxide in patients on peritoneal dialysis.

BACKGROUND: Sucroferric oxyhydroxide is a noncalcium, iron-based phosphate binder that demonstrated sustained serum phosphorus control, good tolerability and lower pill burden compared with sevelamer carbonate (sevelamer) in a Phase 3 study conducted in dialysis patients. This subanalysis examines the efficacy and tolerability of sucroferric oxyhydroxide and sevelamer in the peritoneal dialysis (PD) patient population. METHODS: The initial study (NCT01324128) and its extension (NCT01464190) were multicenter, Phase 3, open-label, randomized (2:1), active-controlled trials comparing sucroferric oxyhydroxide (1.0-3.0 g/day) with sevelamer (2.4-14.4 g/day) in dialysis patients over 52 weeks in total. RESULTS: In the overall study, 84/1055 (8.1%) patients received PD and were eligible for efficacy analysis (sucroferric oxyhydroxide, n = 56; sevelamer, n = 28). The two groups were broadly comparable to each other and to the overall study population. Serum phosphorus concentrations decreased comparably with both phosphate binders by week 12 (mean change from baseline - 0.6 mmol/L). Over 52 weeks, sucroferric oxyhydroxide effectively reduced serum phosphorus concentrations to a similar extent as sevelamer; 62.5% and 64.3% of patients, respectively, were below the Kidney Disease Outcomes Quality Initiative target range (≤1.78 mmol/L). This was achieved with a lower pill burden (3.4 ± 1.3 versus 8.1 ± 3.7 tablets/day) with sucroferric oxyhydroxide compared with sevelamer. Treatment adherence rates were 91.2% with sucroferric oxyhydroxide and 79.3% with sevelamer. The proportion of patients reporting at least one treatment-emergent adverse event was 86.0% with sucroferric oxyhydroxide and 93.1% with sevelamer. The most common adverse events with both treatments were gastrointestinal: diarrhea and discolored feces with sucroferric oxyhydroxide and nausea, vomiting and constipation with sevelamer. CONCLUSIONS: Sucroferric oxyhydroxide is noninferior to sevelamer for controlling serum phosphorus in patients undergoing PD, while providing a relatively low pill burden and a high rate of adherence.

Four-Week Studies of Oral Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitor GSK1278863 for Treatment of Anemia.

Hypoxia-inducible factor prolyl hydroxylase inhibitors stabilize levels of hypoxia-inducible factor that upregulate transcription of multiple genes associated with the response to hypoxia, including production of erythropoietin. We conducted two phase 2a studies to explore the relationship between the dose of the hypoxia-inducible factor-prolyl hydroxylase inhibitor GSK1278863 and hemoglobin response in patients with anemia of CKD (baseline hemoglobin 8.5-11.0 g/dl) not undergoing dialysis and not receiving recombinant human erythropoietin (nondialysis study) and in patients with anemia of CKD (baseline hemoglobin 9.5-12.0 g/dl) on hemodialysis and being treated with stable doses of recombinant human erythropoietin (hemodialysis study). Participants were randomized 1:1:1:1 to a once-daily oral dose of GSK1278863 (0.5 mg, 2 mg, or 5 mg) or control (placebo for the nondialysis study; continuing on recombinant human erythropoietin for the hemodialysis study) for 4 weeks, with a 2-week follow-up. In the nondialysis study, GSK1278863 produced dose-dependent effects on hemoglobin, with the highest dose resulting in a mean increase of 1 g/dl at week 4. In the hemodialysis study, treatment with GSK1278863 in the 5-mg arm maintained mean hemoglobin concentrations after the switch from recombinant human erythropoietin, whereas mean hemoglobin decreased in the lower-dose arms. In both studies, the effects on hemoglobin occurred with elevations in endogenous erythropoietin within the range usually observed in the respective populations and markedly lower than those in the recombinant human erythropoietin control arm in the hemodialysis study, and without clinically significant elevations in plasma vascular endothelial growth factor concentrations. GSK1278863 was generally safe and well tolerated at the doses and duration studied. GSK1278863 may prove an effective alternative for managing anemia of CKD.

Pharmacodynamic Effects of Sucroferric Oxyhydroxide and Sevelamer Carbonate on Vitamin D Receptor Agonist Bioactivity in Dialysis Patients.

BACKGROUND: Many patients with chronic kidney disease are prescribed vitamin D receptor agonists (VDRAs) for the management of secondary hyperparathyroidism. Oral phosphate binders may interact with, and potentially reduce the therapeutic activity of, oral VDRAs. This post hoc analysis of a Phase 3 study evaluated the pharmacodynamic effects of the iron-based phosphate binder sucroferric oxyhydroxide (SFOH) and sevelamer (SEV) carbonate on VDRA activity in dialysis patients. METHODS: One thousand and fifty nine patients were randomized to SFOH 1.0-3.0 g/day (n = 710) or SEV 2.4-14.4 g/day (n = 349) for up to 52 weeks. Potential interactions of SFOH and SEV with VDRAs were assessed using serum intact parathyroid hormone (iPTH) concentrations as a pharmacodynamic biomarker. Three populations of SFOH- and SEV-treated patients were analyzed: Population 1 (n = 187), patients taking concomitant stable doses of oral VDRAs only; Population 2 (n = 250), patients taking no concomitant VDRAs; Population 3 (n = 68), patients taking concomitant stable doses of intravenous paricalcitol only. Populations were compared using a mixed-effects model to obtain the least squares mean change in iPTH from baseline to Week 52. Differences between treatment groups were also compared. RESULTS: In Population 1, iPTH decreased from baseline to Week 52 in the SFOH group (-25.3 pg/ml) but increased in the SEV group (89.8 pg/ml) (p = 0.02). In Population 2, iPTH increased to a similar extent in both treatment groups. In Population 3, iPTH concentrations in both treatment groups decreased to a similar degree (-29.6 and -11.4 pg/ml for SFOH and SEV, respectively; p = 0.87). CONCLUSIONS: In contrast with SEV, SFOH did not appear to impact the iPTH-lowering effect of oral VDRAs.

New Agents in Treatment of Hyperkalemia: an Opportunity to Optimize Use of RAAS Inhibitors for Blood Pressure Control and Organ Protection in Patients with Chronic Kidney Disease.

PURPOSE OF REVIEW: The overactive renin-angiotensin-aldosterone system (RAAS) plays an important part in many pathologic conditions including hypertension, heart failure, and renal disease. Hyperkalemia, a potentially life-threatening side effect of RAAS inhibitors, limits their use. The recent introduction of new hyperkalemia treatments provides opportunities to take full benefit of RAAS inhibitors. RECENT FINDINGS: Optimizing RAAS inhibition is an important therapeutic goal, particularly in chronic kidney disease. Different strategies have been investigated to achieve this goal, including inhibiting the pathway at multiple steps and using maximum or even supramaximal doses. Hyperkalemia is one of the most significant barriers to all of the strategies mentioned above. Up until the recent past, there have been limited therapeutic options available for the prevention and treatment of hyperkalemia in the long term. New promising agents to treat hyperkalemia in outpatient settings, namely, patiromer and sodium zirconium, may provide a solution. This article will review the benefits and risks of RAAS inhibitors, strategies to optimize their use, and the new hyperkalemia treatments that can lower the risk associated with RAAS inhibiting therapies.