Iron-related parameters in dialysis patients treated with sucroferric oxyhydroxide

Efficacy and safety of sucroferric oxyhydroxide versus sevelamer carbonate: A systematic review and meta-analysis

INTRODUCTION

Phosphate binders are commonly used in patients receiving kidney replacement therapy (KRT), aiming to reduce and maintain serum phosphorus. Chronic kidney disease-mineral and bone disorder has been linked to reduced lifespan and worsened quality of life. This study aims to examine the efficacy and safety of sucroferric oxyhydroxide versus sevelamer carbonate in patients receiving KRT.

METHODS

The data sources examined were MEDLINE (PubMed), Scopus, and the Cochrane Central Register of Controlled Clinical Trials with a search deadline of October 2023. We examined randomized controlled trials that compared sucroferric oxyhydroxide versus sevelamer carbonate in the adult population receiving KRT. We performed a meta-analysis combining the data from trials, using R-studio.

FINDINGS

Inclusion criteria were met by five randomized trials. There was no statistically significant difference in the reduction of serum phosphorus between the two groups (MD: -0.07 mmol/L, 95% CI-random effects: -0.15 to 0.02). In the same line, a non-statistically significant difference was observed in serum i-PTH reduction between the two drugs (MD = -1.53 mg/dL, 95% CI = (-4.45, 1.4), p = 0.26, random effects model). No statistically significant difference was observed in all adverse events between the two groups (odds ratio: 1.11, 95% CI: 0.65-1.88, random effects model). Further analysis of gastrointestinal adverse events revealed that sevelamer carbonate increases gastrointestinal adverse events by up to 60% (odds ratio: 1.60, 95% CI: 1.31-1.97, common (fixed) effect model).

DISCUSSION

This meta-analysis of randomized trials showed that both drugs, sucroferric oxyhydroxide and sevelamer equally and effectively controlled serum phosphorus levels, whereas sucroferric oxyhydroxide revealed a better profile in terms of gastrointestinal adverse events. Sucroferric oxyhydroxide is a valuable option for patients receiving KRT when sevelamer carbonate is more difficult to tolerate.

Regulatory effects of nutritional and metabolic disorders on vascular calcification in chronic kidney disease: a narrative review

Background and Objective

Vascular calcification (VC) is common in chronic kidney disease (CKD) patients and is associated with poor cardiovascular outcomes. This study aims to review nutritive pro-calcifying factors of CKD.

Methods

Electronic databases (PubMed, Embase, and the Cochrane Central Register of Controlled Trials) were searched from 2001 as at July 26, 2022, to select and summarize the basic and clinical studies reporting the effects of malnutrition or metabolic disorders on VC in CKD and the evolving treatments for these nutrient metabolic disorders.

Key Content and Findings

Hyperphosphatemia, calcium load, hypomagnesemia, iron deficiency, lipoprotein(a) abnormalities, protein malnutrition, and vitamin K deficiency secondary to CKD were closely associated with the occurrence and development of VC. Elevated phosphate and calcium levels were essential contributors to VC, yet current phosphate binders with good phosphate-lowering effects had not been shown to delay VC progression in CKD, and it remained challenging on how to identify and prevent calcium overload. Magnesium supplementation was the most promising treatment for mitigating VC, as supported by in vitro and in vivo studies and clinical trials. Correction of iron and vitamin K deficiency might contribute to VC attenuation, yet there was a lack of clinical evidence on CKD patients.

Conclusions

This review highlighted the effects of nutrient metabolism disorders on CKD-VC, and additional studies are needed to further address optimal nutrition strategies for mitigating VC in CKD.

Efficacy and Safety of Sucroferric Oxyhydroxide Compared with Sevelamer Carbonate in Chinese Dialysis Patients with Hyperphosphataemia: A Randomised, Open-Label, Multicentre, 12-Week Phase III Study

INTRODUCTION

This study aimed to investigate the efficacy and safety of sucroferric oxyhydroxide (SFOH) versus sevelamer carbonate in controlling serum phosphorus (sP) in adult Chinese dialysis patients with hyperphosphataemia (sP >1.78 mmol/L).

METHODS

Open-label, randomised (1:1), active-controlled, parallel group, multicentre, phase III study of SFOH and sevelamer at starting doses corresponding to 1,500 mg iron/day and 2.4 g/day, respectively, with 8-week dose titration and 4-week maintenance (NCT03644264). Primary endpoint was non-inferiority analysis of change in sP from baseline to week 12. Secondary endpoints included sP over time and safety.

RESULTS

415 patients were screened; 286 were enrolled and randomised (142 and 144 to SFOH and sevelamer, respectively). Mean (SD) baseline sP: 2.38 (0.57) and 2.38 (0.52) mmol/L, respectively. Mean (SD) change in sP from baseline to week 12: - 0.71 (0.60) versus -0.63 (0.52) mmol/L, respectively; difference (sevelamer minus SFOH) in least squares means (95% CI): 0.08 mmol/L (-0.02, 0.18) with the lower limit of 95% CI above the non-inferiority margin of -0.34 mmol/L. The SFOH group achieved target sP (1.13-1.78 mmol/L) earlier than the sevelamer group (56.5% vs. 32.8% at week 4) and with a lower pill burden (mean 3.7 vs. 9.1 tablets/day over 4 weeks of maintenance, respectively). Safety and tolerability of SFOH was consistent with previous studies, and no new safety signals were observed.

CONCLUSION

SFOH effectively reduced sP from baseline and was non-inferior to sevelamer after 12 weeks of treatment but had a lower pill burden in Chinese dialysis patients with hyperphosphataemia; SFOH benefit-risk profile is favourable in Chinese patients.

Sucroferric oxyhydroxide for hyperphosphatemia: a review of real-world evidence

Hyperphosphatemia is a common complication in dialysis-dependent patients with chronic kidney disease. Most dialysis-dependent patients need oral phosphate binder therapy to control serum phosphorus concentrations. Most phosphate binders have a high daily pill burden, which may reduce treatment adherence and impair phosphorus control. Sucroferric oxyhydroxide is a potent iron-based phosphate binder approved for use in dialysis-dependent patients in 2013. A randomized controlled trial of sucroferric oxyhydroxide demonstrated its efficacy for reduction of serum phosphorus with a lower pill burden than sevelamer carbonate. Clinical trials carefully select patients, monitor adherence, and routinely titrate medications to a protocol-defined goal. Consequently, trials may not reflect real-world use of medications. Since its approval, we and others have performed retrospective and prospective analyses of sucroferric oxyhydroxide in real-world clinical practice in > 6400 hemodialysis and approximately 500 peritoneal dialysis patients in the USA and Europe. Consistent with the clinical trial data, real-world observational studies have demonstrated that sucroferric oxyhydroxide can effectively reduce serum phosphorus with a lower daily pill burden than most other phosphate binders. These studies have also shown sucroferric oxyhydroxide provides effective serum phosphorus control in different treatment settings, including as monotherapy in phosphate binder-naïve patients, in patients switching from other phosphate binders, or when used in combination with other phosphate binders. These observational studies indicate a favorable safety and tolerability profile, and minimal, if any, systemic iron absorption. This article reviews the key results from these observational studies of sucroferric oxyhydroxide and evaluates its role in the management of hyperphosphatemia in clinical practice.

Gut microbiome in hemodialysis patients treated with calcium acetate or treated with sucroferric oxyhydroxide: a pilot study

PURPOSE

It has been proved that the gut microbiome is altered in patients with chronic kidney disease. This contributes to chronic inflammation and increases cardiovascular risk and mortality, especially in those undergoing hemodialysis. Phosphate binders may potentially induce changes in their microbiome. This trial aimed to compare the changes in the gut microbiome of hemodialysis patients treated with calcium acetate to those treated with sucroferric oxyhydroxide.

METHODS

Twelve hemodialysis patients were distributed to receive calcium acetate or sucroferric oxyhydroxide for 5 months. Blood samples (for biochemical analysis) and stool samples (for microbiome analysis) were collected at baseline, 4, 12, and 20 weeks after treatment initiation. Fecal DNA was extracted and a 16S rRNA sequencing library was constructed targeting the V3 and V4 hypervariable regions.

RESULTS

Regarding clinical variables and laboratory parameters, no statistically significant differences were observed between calcium acetate or sucroferric oxyhydroxide groups. When analyzing stool samples, we found that all patients were different (p = 0.001) among themselves and these differences were kept along the 20 weeks of treatment. The clustering analysis in microbial profiles grouped the samples of the same patient independently of the treatment followed and the stage of the treatment.

CONCLUSION

These results suggest that a 5-month treatment with either calcium acetate or sucroferric oxyhydroxide did not modify baseline diversity or baseline bacterial composition in hemodialysis patients, also about the high-variability profiles of the gut microbiome found among these patients.

Crosstalk of fibroblast growth factor 23 and anemia-related factors during the development and progression of CKD (Review)

Fibroblast growth factor 23 (FGF23) plays an important role in the development of chronic kidney disease-mineral bone disorder (CKD-MBD). Abnormally elevated levels of 1,25-dihydroxyvitamin D cause osteocytes to secrete FGF23, which subsequently induces phosphaturia. Recent studies have reported that iron deficiency, erythropoietin (EPO) and hypoxia regulate the pathways responsible for FGF23 production. However, the molecular mechanisms underlying the interactions between FGF23 and anemia-related factors are not yet fully understood. The present review discusses the associations between FGF23, iron, EPO and hypoxia-inducible factors (HIFs), and their impact on FGF23 bioactivity, focusing on recent studies. Collectively, these findings propose interactions between FGF23 gene expression and anemia-related factors, including iron deficiency, EPO and HIFs. Taken together, these results suggest that FGF23 bioactivity is closely associated with the occurrence of CKD-related anemia and CKD-MBD.

The Importance of Phosphate Control in Chronic Kidney Disease

A series of problems including osteopathy, abnormal serum data, and vascular calcification associated with chronic kidney disease (CKD) are now collectively called CKD-mineral bone disease (CKD-MBD). The pathophysiology of CKD-MBD is becoming clear with the emerging of αKlotho, originally identified as a progeria-causing protein, and bone-derived phosphaturic fibroblast growth factor 23 (FGF23) as associated factors. Meanwhile, compared with calcium and parathyroid hormone, which have long been linked with CKD-MBD, phosphate is now attracting more attention because of its association with complications and outcomes. Incidentally, as the pivotal roles of FGF23 and αKlotho in phosphate metabolism have been unveiled, how phosphate metabolism and hyperphosphatemia are involved in CKD-MBD and how they can be clinically treated have become of great interest. Thus, the aim of this review is reconsider CKD-MBD from the viewpoint of phosphorus, its involvement in the pathophysiology, causing complications, therapeutic approach based on the clinical evidence, and clarifying the importance of phosphorus management.

Optimal Phosphate Control Related to Coronary Artery Calcification in Dialysis Patients

BACKGROUND

In patients on maintenance dialysis, cardiovascular mortality risk is remarkably high, which can be partly explained by severe coronary artery calcification (CAC). Hyperphosphatemia has been reported to be associated with the severity of CAC. However, the optimal phosphate range in patients on dialysis remains unknown. This study was planned to compare the effects on CAC progression of two types of noncalcium-based phosphate binders and of two different phosphate target ranges.

METHODS

We conducted a randomized, open-label, multicenter, interventional trial with a two by two factorial design. A total of 160 adults on dialysis were enrolled and randomized to the sucroferric oxyhydroxide or lanthanum carbonate group, with the aim of reducing serum phosphate to two target levels (3.5-4.5 mg/dl in the strict group and 5.0-6.0 mg/dl in the standard group). The primary end point was percentage change in CAC scores during the 12-month treatment.

RESULTS

The full analysis set included 115 patients. We observed no significant difference in percentage change in CAC scores between the lanthanum carbonate group and the sucroferric oxyhydroxide group. On the other hand, percentage change in CAC scores in the strict group (median of 8.52; interquartile range, -1.0-23.9) was significantly lower than that in the standard group (median of 21.8; interquartile range, 10.0-36.1; P=0.006). This effect was pronounced in older (aged 65-74 years) versus younger (aged 20-64 years) participants (P value for interaction =0.003). We observed a similar finding for the absolute change in CAC scores.

CONCLUSIONS

Further study with a larger sample size is needed, but strict phosphate control shows promise for delaying progression of CAC in patients undergoing maintenance hemodialysis.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Evaluate the New Phosphate Iron-Based Binder Sucroferric Oxyhydroxide in Dialysis Patients with the Goal of Advancing the Practice of EBM (EPISODE), jRCTs051180048.

Real-world safety and effectiveness of sucroferric oxyhydroxide for treatment of hyperphosphataemia in dialysis patients: a prospective observational study

Background

The iron-based phosphate binder (PB), sucroferric oxyhydroxide (SFOH), is indicated to control serum phosphorus levels in patients with chronic kidney disease on dialysis.

Methods

This non-interventional, prospective, multicentre, cohort study conducted in seven European countries evaluated the safety and effectiveness of SFOH in dialysis patients with hyperphosphataemia in routine practice. Safety outcomes included adverse drug reactions (ADRs) and changes in iron-related parameters. SFOH effectiveness was evaluated by changes-from-baseline (BL) in serum phosphorus and percentage of patients achieving in-target phosphorus levels.

Results

The safety analysis set included 1365 patients (mean observation: 420.3 ± 239.3 days). Overall, 682 (50.0%) patients discontinued the study. Mean SFOH dose during the observation period was 1172.7 ± 539.9 mg (2.3 pills/day). Overall, 617 (45.2%) patients received concomitant PB(s) during SFOH treatment. ADRs and serious ADRs were observed for 531 (38.9%) and 26 (1.9%) patients. Most frequent ADRs were diarrhoea (194 patients, 14.2%) and discoloured faeces (128 patients, 9.4%). Diarrhoea generally occurred early during SFOH treatment and was mostly mild and transient. Small increases from BL in serum ferritin were observed (ranging from +12 to +75 µg/L). SFOH treatment was associated with serum phosphorus reductions (6.3 ± 1.6 mg/dL at BL versus 5.3 ± 1.8 mg/dL at Month 30; ΔBL: −1.0 mg/dL, P < 0.01). Percentage of patients achieving serum phosphorus ≤4.5 mg/dL increased from 12.0% at BL to 34.8% at Month 30, while the percentage achieving serum phosphorus ≤5.5 mg/dL increased from 29.9% to 63.0%.

Conclusions

SFOH has a favourable safety and tolerability profile in a real-world setting, consistent with results of the Phase 3 study. Moreover, SFOH improved serum phosphorus control with a low daily pill burden.

Real-world management of hyperphosphataemia with sucroferric oxyhydroxide: the VELREAL multicentre study

BACKGROUND

The efficacy and safety of sucroferric oxyhydroxide (SO) have been reported in clinical trials. However, real-life data are scarce. This study presents data on the use, efficacy and safety of SO in real clinical practice.

METHODS

We performed a retrospective multicentre study, without any influence on the prescription decisions, that included 220 patients from 11 Spanish centres. Demographic, treatment, analytical and nutritional parameters and adherence, side effects and dropout rates were collected during 6 months.

RESULTS

SO was initiated due to inadequate control of serum phosphate (P) in 70% of participants and in 24.5% to reduce the number of tablets. Monotherapy with SO increased from 44% to 74.1%, with a reduction in the average daily number of sachets/tablets from six to two. Serum P decreased by 20% (4.6 ± 1.2 versus 5.8 ± 1.3 mg/dL; P < 0.001), with a significant reduction in intact parathyroid hormone levels (P < 0.01). The percentage of patients with adequate serum P control at threshold levels of 5 and 4.5 mg/dL increased by 45.4% and 35.9%, respectively. Serum ferritin was not modified, while the transferrin saturation index increased significantly (P = 0.04). Serum albumin and normalized protein catabolic rate, when normalized by serum P, increased, averaging 37% and 39%, respectively (P < 0.001). Adherent patients increased from 28.2% to 52.7%. Adverse effects were reported by 14.1% of participants, with abandonment of treatment in 9.5%.

CONCLUSIONS

The use of SO in real-life results in better control of serum P, a reduction in the number of tablets and an improvement in therapeutic adherence. In addition, it may be beneficial with regards to secondary hyperparathyroidism and nutritional status.

Intestinal Chelators, Sorbants, and Gut-Derived Uremic Toxins

Chronic kidney disease (CKD) is a highly prevalent condition and is associated with a high comorbidity burden, polymedication, and a high mortality rate. A number of conventional and nonconventional risk factors for comorbidities and mortality in CKD have been identified. Among the nonconventional risk factors, uremic toxins are valuable therapeutic targets. The fact that some uremic toxins are gut-derived suggests that intestinal chelators might have a therapeutic effect. The phosphate binders used to prevent hyperphosphatemia in hemodialysis patients act by complexing inorganic phosphate in the gastrointestinal tract but might conceivably have a nonspecific action on gut-derived uremic toxins. Since phosphorous is a major nutrient for the survival and reproduction of bacteria, changes in its intestinal concentration may impact the gut microbiota’s activity and composition. Furthermore, AST-120 is an orally administered activated charcoal adsorbent that is widely used in Asian countries to specifically decrease uremic toxin levels. In this narrative review, we examine the latest data on the use of oral nonspecific and specific intestinal chelators to reduce levels of gut-derived uremic toxins.

Renoprotective effects of sucroferric oxyhydroxide in a rat model of chronic renal failure

Introduction

Sucroferric oxyhydroxide (PA21) is an efficacious, well-tolerated iron-based phosphate binder and a promising alternative to existing compounds. We compared the effects of PA21 with those of a conventional phosphate binder on renal function, mineral homeostasis and vascular calcification in a chronic kidney disease–mineral and bone disorder (CKD-MBD) rat model.

Methods

To induce stable renal failure, rats were administered a 0.25% adenine diet for 8 weeks. Concomitantly, rats were treated with vehicle, 2.5 g/kg/day PA21, 5.0 g/kg/day PA21 or 3.0 g/kg/day calcium carbonate (CaCO₃). Renal function and calcium/phosphorus/iron metabolism were evaluated during the study course. Renal fibrosis, inflammation, vascular calcifications and bone histomorphometry were quantified.

Results

Rats treated with 2.5 or 5.0 g/kg/day PA21 showed significantly lower serum creatinine and phosphorus and higher ionized calcium levels after 8 weeks of treatment compared with vehicle-treated rats. The better preserved renal function with PA21 went along with less severe anaemia, which was not observed with CaCO₃. Both PA21 doses, in contrast to CaCO₃, prevented a dramatic increase in fibroblast growth factor (FGF)-23 and significantly reduced the vascular calcium content while both compounds ameliorated CKD-related hyperparathyroid bone.

Conclusions

PA21 treatment prevented an increase in serum FGF-23 and had, aside from its phosphate-lowering capacity, a beneficial impact on renal function decline (as assessed by the renal creatinine clearance) and related disorders. The protective effect of this iron-based phosphate binder on the kidney in rats, together with its low pill burden in humans, led us to investigate its use in patients with impaired renal function not yet on dialysis.

The real-world effectiveness of sucroferric oxyhydroxide in European hemodialysis patients: a 1-year retrospective database analysis

BACKGROUND

The iron-based phosphate binder (PB), sucroferric oxyhydroxide (SFOH), demonstrated its effectiveness for lowering serum phosphate levels, with low daily pill burden, in clinical trials of dialysis patients with hyperphosphatemia. This retrospective database analysis evaluated the real-world effectiveness of SFOH for controlling serum phosphate in European hemodialysis patients.

METHODS

De-identified patient data were extracted from a clinical database (EuCliD®) for adult hemodialysis patients from France, Italy, Portugal, Russia and Spain who were newly prescribed SFOH for up to 1 year as part of routine clinical care. Serum phosphate and pill burden were compared between baseline (3-month period before starting SFOH) and four consecutive quarterly periods of SFOH therapy (Q1-Q4; 12 months) in the overall cohort and three subgroups: PB-naïve patients treated with SFOH monotherapy (mSFOH), and PB-pretreated patients who were either switched to SFOH monotherapy (PB → mSFOH), or received SFOH in addition to another PB (PB + SFOH).

RESULTS

1096 hemodialysis patients (mean age: 60.6 years; 65.8% male) were analyzed, including 796, 188 and 53 patients in, respectively, the PB + SFOH, mSFOH, and PB → mSFOH groups. In the overall cohort, serum phosphate decreased significantly from 1.88 mmol/L at baseline to 1.77-1.69 mmol/L during Q1-Q4, and the proportion of patients achieving serum phosphate ≤1.78 mmol/L increased from 41.3% at baseline to 56.2-62.7% during SFOH treatment. Mean PB pill burden decreased from 6.3 pills/day at baseline to 5.0-5.3 pills/day during Q1-Q4. The subgroup analysis found the proportion of patients achieving serum phosphate ≤1.78 mmol/L increased significantly from baseline during SFOH treatment in the PB + SFOH group (from 38.1% up to 60.9% [Q2]) and the mSFOH group (from 49.5% up to 75.2% [Q2]), but there were no significant changes in the PB → mSFOH group. For the PB + SFOH group, serum phosphate reductions were achieved with a similar number of PB pills prescribed at baseline prior to SFOH treatment (6.5 vs 6.2 pills/day at Q4). SFOH daily pill burden was low across all 3 subgroups (2.1-2.8 pills/day).

CONCLUSION

In this real-world study of European hemodialysis patients, prescription of SFOH as monotherapy to PB-naïve patients, or in addition to existing PB therapy, was associated with significant improvements in serum phosphate control and a low daily pill burden.

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.

Sucroferric Oxyhydroxide in Maintenance Hemodialysis: A Retrospective, Comparative Cohort Study

Rationale & Objective

High pill burden associates with reduced phosphate-binder adherence among dialysis patients, contributing to elevated serum phosphorus levels. We compared the real-world effectiveness of sucroferric oxyhydroxide (SO) versus other phosphate binders in hemodialysis patients over 2 years.

Study Design

Retrospective cohort study.

Setting & Participants

Adult in-center hemodialysis patients prescribed 2 years of uninterrupted SO therapy (maintenance SO; n = 222) compared with patients who discontinued SO therapy (discontinued SO; n = 596) within 90 days of first prescription and switched to other phosphate binder(s) for 2 years.

Exposures

Phosphate binders.

Outcomes

Achievement of serum phosphorus levels ≤ 5.5 mg/dL, pill burden, and hospitalizations.

Analytical Approach

Comparisons were made quarterly (Q1-Q8) between maintenance SO and discontinued SO using Poisson and mixed-effects linear regression.

Results

Patients achieving serum phosphorus levels ≤ 5.5 mg/dL increased from baseline in maintenance SO (46 [20.7%] to a maximum of 104 [46.8%; P < 0.001]) and discontinued SO (96 [16.1%] to a maximum of 201 [33.7%]; P < 0.001). 100 (45%) maintenance SO patients achieved target serum phosphorus levels at Q8 with 3.1 fewer pills per day from baseline (7.5 to 4.4 pills per day; P < 0.001), and 190 (31.9%) discontinued SO patients achieved serum phosphorus levels ≤ 5.5 mg/dL at Q8 with pill burden unchanged (9.1 to 9.3 pills per day; P = 0.3). Among all patients during 2 years, mean serum phosphorus levels decreased by -0.66 mg/dL and -0.45 mg/dL (maintenance SO vs discontinued SO; P = 0.014), and mean pill burden decreased in maintenance SO (8.5 to 5.1 pills per day; P < 0.001), but not in discontinued SO (11.6 to 10.9 pills per day; P = 0.2). The serum phosphorus level decrease with SO was confirmed in a sensitivity analysis including patients with SO therapy for 2 or fewer years. Compared with discontinued SO, maintenance SO patients had 35.6 fewer hospitalizations per 100 patient-years (incidence rate ratio, 0.75 [95% CI, 0.58-0.96]).

Limitations

No data for treatment indication, tolerance, or adherence.

Conclusions

Patients maintained on SO therapy were more likely to achieve target serum phosphorus levels, use 50% fewer phosphate-binder pills per day, and have fewer hospital admissions than patients switched to treatment with other binders.

One-Year Historical Cohort Study of the Phosphate Binder Sucroferric Oxyhydroxide in Patients on Maintenance Hemodialysis

OBJECTIVE

The high pill burden of many phosphate binders (PBs) may contribute to increased prevalence of hyperphosphatemia and poor nutritional status observed among patients undergoing maintenance hemodialysis therapy. We examined the real-world effectiveness of sucroferric oxyhydroxide (SO), a PB with low pill burden, in managing serum phosphorus in patients with prevalent hemodialysis over a 1-year period.

DESIGN

Historical cohort analyses of de-identified electronic medical records.

SUBJECTS

In-center hemodialysis patients switched from another PB to SO therapy as part of routine care with 12 months of uninterrupted SO prescriptions recorded, and documented serum phosphorus levels were eligible for inclusion. Clinical data were extracted from a pharmacy service, FreseniusRx, database and Fresenius Kidney Care clinical data warehouse.

MAIN OUTCOME MEASURES

Comparisons were made between the 91-day period before SO initiation (i.e., baseline) and the 4 consecutive 91-day intervals of SO treatment (Q1-Q4). Clinical measures included achievement of target phosphorus levels (≤5.5 mg/dL) and mean number of PB pills/day.

RESULTS

Among 530 analyzed patients, the proportion achieving target serum phosphorus levels increased by >100% 1 year after switching to SO therapy, that is, from 17.7% at baseline to 24.5%, 30.5%, 36.4%, and 36.0% at Q1 through Q4, respectively (P < .0001 for all). Reductions in serum phosphorus were observed at all follow-up timepoints (P < .0001), irrespective of baseline PB. From a mean baseline PB pill burden of 8.5 pills/day, patients experienced an average 50% pill burden reduction during SO treatment (P < .0001). Phosphorus-attuned albumin and phosphorus-attuned protein intake (normalized protein catabolic rate) improved significantly after transition to SO (P < .0001). The effectiveness of SO was evident in prespecified subgroups of interest (i.e., black/African-American patients, Hispanic/Latino patients, and women).

CONCLUSION

Among patients on hemodialysis, switching to SO resulted in a 2-fold greater likelihood of achieving target phosphorus levels while halving daily PB pill burden. Increases in phosphorus-attuned albumin and protein intake suggest improved nutritional status.

Strategies for Phosphate Control in Patients With CKD

Hyperphosphatemia is a common complication in patients with chronic kidney disease (CKD), particularly in those requiring renal replacement therapy. The importance of controlling serum phosphate has long been recognized based on observational epidemiological studies that linked increased phosphate levels to adverse outcomes and higher mortality risk. Experimental data further supported the role of phosphate in the development of bone and cardiovascular diseases. Recent advances in our understanding of the mechanisms involved in phosphate homeostasis have made it clear that the serum phosphate concentration depends on a complex interplay among the kidneys, intestinal tract, and bone, and is tightly regulated by a complex endocrine system. Moreover, the source of dietary phosphate and the use of phosphate-based additives in industrialized foods are additional factors that are of particular importance in CKD. Not surprisingly, the management of hyperphosphatemia is difficult, and, despite a multifaceted approach, it remains unsuccessful in many patients. An additional issue is the fact that the supposedly beneficial effect of phosphate lowering on hard clinical outcomes in interventional trials is a matter of ongoing debate. In this review, we discuss currently available treatment approaches for controlling hyperphosphatemia, including dietary phosphate restriction, reduction of intestinal phosphate absorption, phosphate removal by dialysis, and management of renal osteodystrophy, with particular focus on practical challenges and limitations, and on potential benefits and harms.

Regulation of Fibroblast Growth Factor 23 by Iron, EPO, and HIF

Purpose of review

Fibroblast growth factor-23 (FGF23) is the key hormone produced in bone critical for phosphate homeostasis. Elevated serum phosphorus and 1,25dihydroxyvitaminD stimulates FGF23 production to promote renal phosphate excretion and decrease 1,25dihydroxyvitaminD synthesis. Thus completing the feedback loop and suppressing FGF23. Unexpectedly, studies of common and rare heritable disorders of phosphate handling identified links between iron and FGF23 demonstrating novel regulation outside the phosphate pathway.

Recent Findings

Iron deficiency combined with an FGF23 cleavage mutation was found to induce the autosomal dominant hypophosphatemic rickets phenotype. Physiological responses to iron deficiency, such as erythropoietin production as well as hypoxia inducible factor activation, have been indicated in regulating FGF23. Additionally, specific iron formulations, used to treat iron deficiency, alter post-translational processing thereby shifting FGF23 protein secretion.

Summary

Molecular and clinical studies revealed that iron deficiency, through several mechanisms, alters FGF23 at the transcriptional and post-translational level. This review will focus upon the novel discoveries elucidated between iron, its regulators, and their influence on FGF23 bioactivity.

Evaluation of changes in ferritin levels during sucroferric oxyhydroxide treatment

Background

A sub-analysis of a Phase III study was conducted to identify factors that might predict increased ferritin levels during long-term sucroferric oxyhydroxide (SO) treatment in hemodialysis patients.

Methods

The open-label, multicenter, Phase III study assessed the efficacy and safety of SO 750–3000 mg/day for 52 weeks in Japanese patients with chronic renal failure and hyperphosphatemia. A total of 125 of 161 patients from the Phase III trial, and who had data for ferritin levels after 28 weeks of SO treatment, were evaluated.

Results

Baseline ferritin was the strongest contributor (P < 0.0001) to ferritin increases during SO treatment. By Week 28, there were significant differences (P < 0.05/3) in ferritin increases between patients with higher [quartile 4 (Q4)] versus lower (Q1, Q2 and Q3) baseline ferritin. An erythropoiesis-stimulating agent dosage reduction was observed in patients with the lowest baseline ferritin level (Q1), and only slight reductions were noted in the other patient subsets. SO dosages administered to patients in baseline ferritin quartiles Q2, Q3 and Q4 were comparable throughout the study with slight fluctuations. SO dosages in Q1 were considerably lower than those in the other quartiles.

Conclusions

In summary, of the baseline variables found to predict increased ferritin, and changes in iron-related parameters, during SO treatment in Japanese chronic kidney disease patients undergoing hemodialysis, baseline ferritin was the most relevant variable.

Phosphate binders for preventing and treating chronic kidney disease-mineral and bone disorder (CKD-MBD)

BACKGROUND

Phosphate binders are used to reduce positive phosphate balance and to lower serum phosphate levels for people with chronic kidney disease (CKD) with the aim to prevent progression of chronic kidney disease-mineral and bone disorder (CKD-MBD). This is an update of a review first published in 2011.

OBJECTIVES

The aim of this review was to assess the benefits and harms of phosphate binders for people with CKD with particular reference to relevant biochemical end-points, musculoskeletal and cardiovascular morbidity, hospitalisation, and death.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 12 July 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs of adults with CKD of any GFR category comparing a phosphate binder to another phosphate binder, placebo or usual care to lower serum phosphate. Outcomes included all-cause and cardiovascular death, myocardial infarction, stroke, adverse events, vascular calcification and bone fracture, and surrogates for such outcomes including serum phosphate, parathyroid hormone (PTH), and FGF23.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies for inclusion and extracted study data. We applied the Cochrane 'Risk of Bias' tool and used the GRADE process to assess evidence certainty. We estimated treatment effects using random-effects meta-analysis. Results were expressed as risk ratios (RR) for dichotomous outcomes together with 95% confidence intervals (CI) or mean differences (MD) or standardised MD (SMD) for continuous outcomes.

MAIN RESULTS

We included 104 studies involving 13,744 adults. Sixty-nine new studies were added to this 2018 update.Most placebo or usual care controlled studies were among participants with CKD G2 to G5 not requiring dialysis (15/25 studies involving 1467 participants) while most head to head studies involved participants with CKD G5D treated with dialysis (74/81 studies involving 10,364 participants). Overall, seven studies compared sevelamer with placebo or usual care (667 participants), seven compared lanthanum to placebo or usual care (515 participants), three compared iron to placebo or usual care (422 participants), and four compared calcium to placebo or usual care (278 participants). Thirty studies compared sevelamer to calcium (5424 participants), and fourteen studies compared lanthanum to calcium (1690 participants). No study compared iron-based binders to calcium. The remaining studies evaluated comparisons between sevelamer (hydrochloride or carbonate), sevelamer plus calcium, lanthanum, iron (ferric citrate, sucroferric oxyhydroxide, stabilised polynuclear iron(III)-oxyhydroxide), calcium (acetate, ketoglutarate, carbonate), bixalomer, colestilan, magnesium (carbonate), magnesium plus calcium, aluminium hydroxide, sucralfate, the inhibitor of phosphate absorption nicotinamide, placebo, or usual care without binder. In 82 studies, treatment was evaluated among adults with CKD G5D treated with haemodialysis or peritoneal dialysis, while in 22 studies, treatment was evaluated among participants with CKD G2 to G5. The duration of study follow-up ranged from 8 weeks to 36 months (median 3.7 months). The sample size ranged from 8 to 2103 participants (median 69). The mean age ranged between 42.6 and 68.9 years.Random sequence generation and allocation concealment were low risk in 25 and 15 studies, respectively. Twenty-seven studies reported low risk methods for blinding of participants, investigators, and outcome assessors. Thirty-one studies were at low risk of attrition bias and 69 studies were at low risk of selective reporting bias.In CKD G2 to G5, compared with placebo or usual care, sevelamer, lanthanum, iron and calcium-based phosphate binders had uncertain or inestimable effects on death (all causes), cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification. Sevelamer may lead to constipation (RR 6.92, CI 2.24 to 21.4; low certainty) and lanthanum (RR 2.98, CI 1.21 to 7.30, moderate certainty) and iron-based binders (RR 2.66, CI 1.15 to 6.12, moderate certainty) probably increased constipation compared with placebo or usual care. Lanthanum may result in vomiting (RR 3.72, CI 1.36 to 10.18, low certainty). Iron-based binders probably result in diarrhoea (RR 2.81, CI 1.18 to 6.68, high certainty), while the risks of other adverse events for all binders were uncertain.In CKD G5D sevelamer may lead to lower death (all causes) (RR 0.53, CI 0.30 to 0.91, low certainty) and induce less hypercalcaemia (RR 0.30, CI 0.20 to 0.43, low certainty) when compared with calcium-based binders, and has uncertain or inestimable effects on cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification. The finding of lower death with sevelamer compared with calcium was present when the analysis was restricted to studies at low risk of bias (RR 0.50, CI 0.32 to 0.77). In absolute terms, sevelamer may lower risk of death (all causes) from 210 per 1000 to 105 per 1000 over a follow-up of up to 36 months, compared to calcium-based binders. Compared with calcium-based binders, lanthanum had uncertain effects with respect to all-cause or cardiovascular death, myocardial infarction, stroke, fracture, or coronary artery calcification and probably had reduced risks of treatment-related hypercalcaemia (RR 0.16, CI 0.06 to 0.43, low certainty). There were no head-to-head studies of iron-based binders compared with calcium. The paucity of placebo-controlled studies in CKD G5D has led to uncertainty about the effects of phosphate binders on patient-important outcomes compared with placebo.It is uncertain whether the effects of binders on clinically-relevant outcomes were different for patients who were and were not treated with dialysis in subgroup analyses.

AUTHORS' CONCLUSIONS

In studies of adults with CKD G5D treated with dialysis, sevelamer may lower death (all causes) compared to calcium-based binders and incur less treatment-related hypercalcaemia, while we found no clinically important benefits of any phosphate binder on cardiovascular death, myocardial infarction, stroke, fracture or coronary artery calcification. The effects of binders on patient-important outcomes compared to placebo are uncertain. In patients with CKD G2 to G5, the effects of sevelamer, lanthanum, and iron-based phosphate binders on cardiovascular, vascular calcification, and bone outcomes compared to placebo or usual care, are also uncertain and they may incur constipation, while iron-based binders may lead to diarrhoea.

Sucroferric oxyhydroxide decreases serum phosphorus level and fibroblast growth factor 23 and improves renal anemia in hemodialysis patients

Objective

Sucroferric oxyhydroxide, a novel iron-based phosphate-binder, has been shown to have beneficial effects in lowering serum phosphorus levels and improving renal anemia in clinical studies. Although an effect of this agent on fibroblast growth factor 23 (FGF23) has been reported in an animal study, there is little clinical data supporting this finding. This study aimed to evaluate the effect on chronic kidney disease-mineral and bone disorder, FGF23, renal anemia, iron-related parameters, adverse events of sucroferric oxyhydroxide in hemodialysis patients.

Results

Hemodialysis patients, receiving existing hyperphosphatemia drugs with insufficient benefit, were administered sucroferric oxyhydroxide with/without calcium carbonate for 16 weeks. Serum phosphorus level declined rapidly in Week 8 (p < 0.0001) and this decrease persisted until Week 16 (p < 0.0001). FGF23 decreased (p = 0.0412, Week 16), and hemoglobin increased (p < 0.0001, Week 16). Cumulative dose of erythropoiesis-stimulating agents (p = 0.0122, Week 16), and intravenous iron (p = 0.0233, Week 12) decreased. All adverse reactions were mild, and diarrhea was the most frequently observed adverse reaction (16.7%). Therefore, hyperphosphatemia treatment with sucroferric oxyhydroxide may safely improve serum phosphorus level, renal anemia, FGF23, and other factors that affect the prognosis of hemodialysis patients.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3483-6) contains supplementary material, which is available to authorized users.

Current and potential treatment options for hyperphosphatemia

INTRODUCTION

Hyperphosphatemia is common in late stages of chronic kidney disease and is often associated with elevated parathormone levels, abnormal bone mineralization, extra-osseous calcification, and increased risk of cardiovascular events and death. Several classes of oral phosphate binders are available to help control plasma phosphorus levels. Although effective at lowering serum phosphorus, they all have safety, tolerability, and compliance issues that need to be considered when selecting which one to use.

AREAS COVERED

This paper reviews the most established treatment options for hyperphosphatemia, in patients with chronic kidney disease, focusing on the new inhibitors of active phosphate absorption.

EXPERT OPINION

The prevention and the treatment of hyperphosphatemia is today far to be satisfactory. Nonetheless, an extending range of phosphate binders are now available. Aluminum has potentially serious toxic risks. Calcium-based binders are very effective but can lead to hypercalcemia and/or positive calcium balance and progression of cardiovascular calcification. No long-term data are available for the new calcium acetate/magnesium combination product. Lanthanum is an effective phosphate binder, and long-term effects of tissue deposition seem clinically irrelevant. Sevelamer, appear to have profiles that would lead to pleiotropic effects and reduced progression of vascular calcification, and the main adverse events seen with these agents are gastrointestinal. Iron has a powerful capability of binding phosphate, thus numerous preparations are available, both with and without significant systemic absorption of the iron component. The inhibitors of active intestinal phosphate transport, with their very selective mechanism of action and low pill burden seem the most interesting approach; however, do not seem at present to be effective alone, in reducing serum phosphorus levels.

Real-World Scenario Improvements in Serum Phosphorus Levels and Pill Burden in Peritoneal Dialysis Patients Treated with Sucroferric Oxyhydroxide

BACKGROUND

A database analysis was conducted to assess the effectiveness of sucroferric oxyhydroxide (SO) on lowering serum phosphorus and phosphate binder (PB) pill burden among adult peritoneal dialysis (PD) patients prescribed SO as part of routine care.

METHODS

Adult PD patients (n = 258) prescribed SO through a renal pharmacy service were analyzed. Baseline was 3 months before SO prescription. SO-treated follow-up was for 6 months or until either a new PB was prescribed, SO was not refilled, PD modality changed, or patient was discharged. In-range serum phosphorus was defined as ≤5.5 mg/dL.

RESULTS

At baseline, mean serum phosphorus was 6.59 mg/dL with 10 prescribed PB pills/day. The proportion of patients achieving in-range serum phosphorus increased by 72% from baseline to month 6. Prescribed PB pills/day decreased by 57% (10 at baseline to 4.3 at SO follow-up, p < 0.0001). The mean length of SO follow-up was 5.1 months; SO follow-up ended for 38, 27, and 50 patients at months 4, 5, and 6, respectively, due to no further PB fills, and for 10, 11, and 4 patients at months 4, 5, and 6, respectively, due to another PB prescribed. In patients with baseline serum phosphorus >5.5 mg/dL who achieved in-range serum phosphorus during SO follow-up for ≥1 quarter, a notable improvement in serum phosphorus (6.54 to 5.10 mg/dL, p < 0.0001) was observed, and there was a 53% reduction in PB pill burden (9.9 to 4.7, p < 0.0001).

CONCLUSION

Among PD patients prescribed SO as part of routine care, improvements in serum phosphorus control and >50% reduction in PB pills/day were observed.

Pharmacotherapy in chronic kidney disease hyperphosphatemia – effects on vascular calcification and bone health

Hyperphosphatemia (HP) in patients with chronic kidney disease (CKD) leads to complications such as renal osteodistrophy, cardiovascular calcification and hemodynamic abnormalities, all of them having a serious impact on the survival rate and quality of life. Also, HP is a key pathogenic factor in the development of secondary hyperparathyroidism (SHPT) in CKD. Having in regard the significance of controlling serum phosphorus levels (Pi), in this paper, the needs and obstacles to successful pharmacological management of HP in CKD are presented, with an overview of major classes of phosphate binders (PBs) and other drugs affecting Pi level, such as active vitamin D sterols and calcimimetics (CMs). In addition, their effects on progression of cardiovascular calcification and bone health are elaborated. In this regard, a PubMed search was carried out to capture all abstracts and articles relevant to the topic of CKD, HP and mineral metabolism, bone disorders and vascular/valvular calcification (VC), published from January 2007 to August 2017. The search was limited to English language, with the search terms including drug name AND hyperphosphatemia or cardiovascular calcification or bone disorder. Comparative studies, clinical studies/trials and meta-analyses related to different classes/representatives of PBs, vitamin D analogues and CMs were reviewed and research data related to their efficacy and safety compared. Keywords: chronic kidney disease, hyperphosphatemia, phosphate binders, active vitamin D sterols, calcimimetics, bone disorders, cardiovascular calcification

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.

[Sucroferric oxyhydroxide, a novel iron-based phosphate binder. Which current use in dialysis patients?]

International guidelines suggest lowering elevated phosphorus level to the normal range in patients on dialysis. Among the phosphate-lowering strategies, phosphate binder is frequently used in addition to dietary phosphate restriction and an adequate dialysis strategy. However, serum phosphate concentration higher than 1.78mmol/L is observed in more than 40% of patients justifying the quest for new drugs. Sucroferric oxyhydroxide is one of the new iron-based agents and is available in France since May 2016. A recent international multicentre study showed this new drug to be as efficacious and non-inferior to sevelamer carbonate in magnitude of serum phosphate control. The serum phosphorus-lowering effect was maintained over 1year. When compared to carbonate sevelamer, the pill-burden was half with sucroferric oxyhydroxide because of its high phosphate binding capacity. As previously shown by experimental studies, no risk of iron accumulation was observed since iron absorption is negligible. Discolored feces and diarrhea were fairly frequent side effects. When diarrhea subsides, the tolerability of this new phosphate binder is excellent on a long-term basis.