Hyperphosphataemia in 2019: have we made progress?

PURPOSE OF REVIEW: This review describes recent developments in the management of serum phosphate in dialysis patients, with a focus on the development of recent trials which randomize patients to different levels of control. RECENT FINDINGS: We review the uncertainties around clinical benefits of serum phosphate control and alternative approaches to current management, as well as a multinational attempt to conduct randomized controlled trials in this area. We discuss novel methods of limiting oral phosphate absorption. SUMMARY: Although numerous guidelines and target ranges for serum phosphate management exist, they are largely based on observational data and there is no definitive evidence that good control improves the length or quality of life of dialysis patients. New phosphate binders continue to appear on the market with increasing financial cost but without additional meaningful outcome data. Two recently published trials have demonstrated the feasibility of a large-scale study of differing phosphate levels to test the hypothesis that reduction of serum phosphate is beneficial to dialysis patients. Restriction of oral phosphate intake should not be overlooked.

A randomized controlled trial of different serum phosphate ranges in subjects on hemodialysis.

BACKGROUND: Hyperphosphataemia in dialysis subjects is associated with increased mortality. However cause and effect has not been proven, and the ideal phosphate target range is unknown despite KDOQI's call for studies over 12 years ago. The design and conduct of a randomized controlled trial is challenging because maintaining two groups within differing target ranges of serum phosphate has not been achieved over a long follow-up of 1 year, in a trial setting, before. The SPIRiT study examines the subject acceptance, recruitment and retention rates for such a study in which subjects were randomised to two distinct serum phosphate concentrations, then titrated and maintained over 12 months. METHODS: A two center trial of 104 hemodialysis subjects randomized to lower range LRG 0.8-1.4 mmol/L or 2.5-4.3 mg/dL) and higher range (HRG 1.8-2.4 mmol/L or 5.6-7.4 mg/dL) serum phosphate groups. Two months' titration and ten months' maintenance phase. Interventions were non-calcium phosphate binders, self-help questionnaires, with blood tests at specified time intervals. RESULTS: Thirteen percent of the eligible dialysis population were successfully recruited. A mean separation by serum phosphate of 1.1 mg/dL was achieved and maintained between the groups over 10 months. Drop-out rate was 27% with mortality 10%. Nine subjects in the HRG (17.6%) and two subjects in the LRG (3.8%) died during the study, however the study was not powered to detect significant differences in outcomes. CONCLUSION: Randomizing dialysis subjects to separate treatment targets for serum phosphate can achieve a clinically significant sustained separation over 12 months. A large scale longer term study is required to examine outcomes including mortality. TRIAL REGISTRATION: The trial registration number is ISRCTN24741445 - Date of registration 16th January, retrospectively registered.

Lanthanum carbonate: safety data after 10 years.

Despite 10 years of post-marketing safety monitoring of the phosphate binder lanthanum carbonate, concerns about aluminium-like accumulation and toxicity persist. Here, we present a concise overview of the safety profile of lanthanum carbonate and interim results from a 5-year observational database study (SPD405-404; ClinicalTrials.gov identifier: NCT00567723). The pharmacokinetic paradigms of lanthanum and aluminium are different in that lanthanum is minimally absorbed and eliminated via the hepatobiliary pathway, whereas aluminium shows appreciable absorption and is eliminated by the kidneys. Randomised prospective studies of paired bone biopsies revealed no evidence of accumulation or toxicity in patients treated with lanthanum carbonate. Patients treated with lanthanum carbonate for up to 6 years showed no clinically relevant changes in liver enzyme or bilirubin levels. Lanthanum does not cross the intact blood-brain barrier. The most common adverse effects are mild/moderate nausea, diarrhoea and flatulence. An interim Kaplan-Meier analysis of SPD405-404 data from the United States Renal Data System revealed that the median 5-year survival was 51.6 months (95% CI: 49.1, 54.2) in patients who received lanthanum carbonate (test group), 48.9 months (95% CI: 47.3, 50.5) in patients treated with other phosphate binders (concomitant therapy control group) and 40.3 months (95% CI: 38.9, 41.5) in patients before the availability of lanthanum carbonate (historical control group). Bone fracture rates were 5.9%, 6.7% and 6.4%, respectively. After more than 850 000 person-years of worldwide patient exposure, there is no evidence that lanthanum carbonate is associated with adverse safety outcomes in patients with end-stage renal disease.

Novel phosphate binders: plus ça change, plus c'est la même chose.

Sucroferric oxyhydroxide is a new calcium-free polynuclear iron(III)-oxyhydroxide compound that binds phosphate by ligand exchange. Floege et al. report equivalent phosphate control with a mean dose of three pills daily compared with eight of sevelamer, and suggest that a reduced pill burden may represent an aid to improved adherence. However, there is still no prospective interventional study to demonstrate that reduction in serum phosphate improves patient outcomes for any oral phosphate binder.

Profiling patient attitudes to phosphate binding medication: a route to personalising treatment and adherence support.

OBJECTIVE: Nonadherence to phosphate binding medication (PBM) compromises the efficacy of treatment for chronic kidney disease, but its causes are poorly understood. This study sought to explore patient attitudes towards PBM and to evaluate the utility of the necessity-concerns framework for understanding adherence to PBM. DESIGN: A sample of 221 dialysis patients currently prescribed PBM were surveyed from eight UK renal units. MAIN OUTCOME MEASURES: Demographic data and clinical information, alongside the Beliefs about Medicines Questionnaire and the medication adherence report scale were reported. RESULTS: Low adherence to PBM was predicted by reduced beliefs in personal need for PBM (OR = .34; 95% CI: .14-.83; p < .05), and increased concerns about PBM (OR = 3.17; 95% CI: 1.87-5.37; p < .001). Patients were categorised into attitudinal groups based on their beliefs about PBM and being 'skeptical' of PBM (low necessity beliefs and high concerns) was most associated with low adherence. CONCLUSION: Strategies to improve adherence to PBM should aim to elicit and address patients' beliefs about their personal need for PBM and their concerns about this medication.

Incidence and consequence of acute kidney injury in unselected emergency admissions to a large acute UK hospital trust.

BACKGROUND: AKI is common among hospital in-patients and places a huge financial burden on the UK National Health Service, causing increased length of hospital stay and use of critical care services, with increased requirement for complex interventions including dialysis. This may account for up to 0.6% of the total Health Service budget. To investigate the incidence and consequences of AKI, all unselected emergency admissions to a large acute UK single centre University Teaching Hospital over two separate 7 day periods were reviewed. METHODS: A retrospective audit of 745 case records was undertaken (54.6% male) including laboratory data post-discharge or death, with classification of AKI by RIFLE, AKIN and AKIB criteria. Participants were included whether admitted via their general practitioners, the emergency department, or as tertiary specialty transfers. Outcome measures were presence or absence of AKI recorded using each of the three AKI criteria, length of hospital stay (LOS), admission to, and LOS in critical care, and mortality. The most severe grade of AKI only, at any time during the admission, was recorded to prevent double counting. Renal outcome was determined by requirement for renal replacement therapy (RRT), and whether those receiving RRT remained dialysis dependent or not. RESULTS: AKI incidence was 25.4% overall. With approximately one third present on admission and two thirds developing post admission. The AKI group had LOS almost three times higher than the non AKI group (10 vs 4 days). Requirement for critical care beds was 8.1% in the AKI group compared to 1.7% in non AKI group. Overall mortality was 5.5%, with the AKI group at 11.4% versus 3.3% in the non AKI group. CONCLUSIONS: AKI in acute unselected hospital admissions is more common than existing literature suggests, affecting 25% of unselected admissions. In many this is relatively mild and may resolve spontaneously, but is associated with increased LOS, likelihood of admission to critical care, and risk of death. If targeted effective interventions can be developed it seems likely that substantial clinical benefits for the patient, as well as financial and structural benefits for the healthcare organisation may accrue.

Outcomes of peritoneal dialysis patients and switching to hemodialysis: a competing risks analysis.

BACKGROUND: We performed a review of a large incident peritoneal dialysis cohort to establish the impact of current practice and that of switching to hemodialysis. METHODS: Patients starting peritoneal dialysis between 2004 and 2010 were included and clinical data at start of dialysis recorded. Competing risk analysis and Cox proportional hazards model with time-varying covariate (technique failure) were used. RESULTS: Of 286 patients (median age 57 years) followed for a median of 24.2 months, 76 were transplanted and 102 died. Outcome probabilities at 3 and 5 years respectively were 0.69 and 0.53 for patient survival (or transplantation) and 0.33 and 0.42 for technique failure. Peritonitis caused technique failure in 42%, but ultrafiltration failure accounted only for 6.3%. Davies comorbidity grade, creatinine and obesity (but not residual renal function or age) predicted technique failure. Due to peritonitis deaths, technique failure was an independent predictor of death hazard. When successful switch to hemodialysis (surviving more than 60 days after technique failure) and its timing were analyzed, no adverse impact on survival in adjusted analysis was found. However, hemodialysis via central venous line was associated with an elevated death hazard as compared to staying on peritoneal dialysis, or hemodialysis through a fistula (adjusted analysis hazard ratio 1.97 (1.02 - 3.80)). CONCLUSIONS: Once the patients survive the first 60 days after technique failure, the switch to hemodialysis does not adversely affect patient outcomes. The nature of vascular access has a significant impact on outcome after peritoneal dialysis failure.

Variability in parathyroid hormone assays confounds clinical practice in chronic kidney disease patients.

BACKGROUND: Intact parathyroid hormone (iPTH) measurements are used to guide therapy in renal patients, but variability in results can occur depending on the assay used. This study has investigated iPTH assay variation in North West England and paired data with regional audit data to determine clinical relevance of assay variability. METHODS: Thirty-seven haemodialysis patients had blood taken (EDTA plasma, and serum), and samples were processed at 17 laboratories that analyse iPTH for North West dialysis patients. Correction factors were calculated and applied to the iPTH assay results to enable direct comparisons. These correction factors were also applied to Regional Audit data to determine if iPTH assay variability explains the variation in unit performance in achieving PTH targets. RESULTS: The iPTH results from the 37 patients were significantly different when either analysed by different assays and/or different laboratories (P < 0.001). The Abbott Architect method consistently produced the highest iPTH results. Of the 37 patients, between 49% and 65% would achieve the Kidney Disease: Improving Global Outcomes (KDIGO) iPTH target depending on the assay used. When results were adjusted using correction factors, 21% of the patients would require a change of management according to guidelines. Data from all haemodialysis units submitted for the regional audit were adjusted to the Roche assay and this led to a small change in achievement of KDIGO iPTH targets in individual units when compared to each other. CONCLUSIONS: A combination of iPTH assay variability and diversity in clinical management leads to variation in achieving iPTH targets. Both need to be improved and/or standardized to improve patient care.

Lanthanum carbonate versus placebo for management of hyperphosphatemia in patients undergoing peritoneal dialysis: a subgroup analysis of a phase 2 randomized controlled study of dialysis patients.

BACKGROUND: This short-term study assessed the efficacy and safety of lanthanum carbonate in the treatment of hyperphosphatemia in dialysis patients; here, we report a prespecified subgroup analysis of patients undergoing peritoneal dialysis. METHODS: Men and women (n=39) who had received continuous ambulatory peritoneal dialysis for chronic kidney disease for 6 months or more were enrolled in eight renal medicine departments in the United Kingdom. A 2-week washout period was followed by a 4-week dose-titration phase during which patients received lanthanum carbonate titrated up to 2250 mg/day. This was followed by a 4-week, randomized, placebo-controlled, parallel-group phase during which patients continued to receive either lanthanum carbonate at the titrated dose, or a matched dose of placebo. The main outcome measure was control of serum phosphate levels (1.3-1.8 mmol/l) at the end of the parallel-group phase. RESULTS: Serum phosphate was controlled in 3/39 (8%) patients at the beginning of the dose-titration phase (after washout) and in 18/31 (58%) patients treated with lanthanum carbonate at its end. After the parallel-group phase, 60% of lanthanum carbonate-treated patients and 10% of those receiving placebo had controlled serum phosphate. There was no difference in mean (95% confidence interval) serum phosphate levels between groups at randomization: lanthanum carbonate, 1.57 (1.34-1.81) mmol/l; placebo, 1.58 (1.40-1.76) mmol/l (p=0.96). However, a difference was seen at the end of the parallel-group phase: lanthanum carbonate, 1.56 (1.33-1.79) mmol/l; placebo, 2.25 (1.81-2.68) mmol/l (p=0.0015). There were no clinically important changes in nutritional parameters and no serious treatment-related adverse events were recorded. CONCLUSIONS: At doses up to 2250 mg/day, lanthanum carbonate is well tolerated and controls hyperphosphatemia effectively. Treatment with higher doses of lanthanum carbonate may allow patients undergoing peritoneal dialysis the potential to increase their dietary protein intake without compromising their phosphate control.

Use of magnesium as a drug in chronic kidney disease.

From chronic kidney disease (CKD) Stage 4 onwards, phosphate binders are needed in many patients to prevent the development of hyperphosphataemia, which can result in disturbed bone and mineral metabolism, cardiovascular disease and secondary hyperparathyroidism. In this review, we re-examine the use of magnesium-containing phosphate binders for patients with CKD, particularly as their use circumvents problems such as calcium loading, aluminum toxicity and the high costs associated with other agents of this class. The use of magnesium hydroxide in the 1980s has been superseded by magnesium carbonate, as the hydroxide salt was associated with poor gastrointestinal tolerability, whereas studies with magnesium carbonate show much better gastrointestinal profiles. The use of combined magnesium- and calcium-based phosphate binder regimens allows a reduction in the calcium load, and magnesium and calcium regimen comparisons show that magnesium may be as effective a phosphate binder as calcium. A large well-designed trial has recently shown that a drug combining calcium acetate and magnesium carbonate was non-inferior in terms of lowering serum phosphate to sevelamer-HCl and had an equally good tolerability profile. Because of the high cost of sevelamer and lanthanum carbonate, the use of magnesium carbonate could be advantageous and drug acquisition cost savings would compensate for the cost of introducing routine magnesium monitoring, if this is thought to be necessary and not performed anyway. Moreover, given the potential cost savings, it may be time to re-investigate magnesium-containing phosphate binders for CKD patients with further well-designed clinical research using vascular end points.

Pharmacology, efficacy and safety of oral phosphate binders.

The ideal serum level of phosphate in patients on dialysis, and the benefits of controlling levels of phosphate in serum remain unclear despite observational studies that associate phosphate levels with mortality. In the absence of robust data from trials, current guidelines are necessarily based on opinion. Oral phosphate binders are required by the majority of patients on dialysis, and all of these binders can control serum levels of phosphate to similar degrees. Patient preference and adherence to prescribed therapy is at least as important as the efficacy of the prescribed binder. Avoidance of calcium-containing binders has become accepted practice where the alternatives are affordable, but incontrovertible evidence in favor of this approach is lacking. Use of sevelamer and lanthanum avoids calcium loading, but at considerable financial cost and with no reliable patient outcome data to prove their value. Additional approaches to aid control of serum levels of phosphate include blockade of gastrointestinal phosphate absorption and possibly binding of salivary phosphate. Importantly, the role of phosphate control in determining patient outcomes must be quantified, which is likely to require a large randomized, controlled study of two levels of phosphate control. Without such a study we will continue to rely on observational data with all its uncertainties and potential to mislead.

Enabling self-management: selecting patients for home dialysis?

Pre-emptive living donor transplantation should always be promoted as the first-line treatment for kidney failure. Where that is not possible, patients must receive timely information and advice regarding all dialysis options available, including home-based peritoneal dialysis and haemodialysis. Where a dialysis unit enables and actively encourages self-management, patients will tend to select themselves, and if well motivated may overcome significant difficulties to exceed the expectations or predictions of dialysis staff. Patients then become advocates themselves and can provide other patients with the necessary motivation to consider a home treatment, such that they approach staff, rather than vice versa. For staff to be able to talk to patients with confidence requires direct experience of home dialysis, but in units which do not have a full range of home therapies, this may initially be difficult. Visiting patients in their home environment is an essential part of training for both medical and nursing staff. Before a patient is able to begin to engage in discussion about any dialysis therapy, they must have reached a point of acceptance that dialysis is necessary. If they are not at this point, then any attempt at 'education' will be largely futile. Once a patient has arrived at the point of choosing a home therapy, the pathway to their first dialysis at home must be as smooth and problem-free as possible.

Update and critical appraisal of sevelamer in the management of chronic renal failure.

Sevelamer (Renagel and Renvela), is an orally administered weakly basic anion exchange resin that binds dietary phosphate in the gastrointestinal tract, and is approved for use in the US, Europe and many other countries for the treatment of hyperphosphatemia in adult patients on hemodialysis or peritoneal dialysis. Clinical evidence shows that sevelamer is at least as effective as calcium-based oral phosphate binders in controlling serum phosphate, but with a lower incidence of hypercalcemia. Whilst sevelamer hydrochloride is associated with mild acidosis, sevelamer carbonate does not have this drawback. Use of sevelamer and avoidance of calcium-based binders may slow the progression of vascular calcification in hemodialysis patients, and it also reduces serum low-density lipoprotein-cholesterol levels. There was no between-group difference in all-cause mortality between sevelamer and calcium-based phosphate binder therapy in the primary efficacy analysis of the large (n >2100), 3-year DCOR trial. In the smaller (n = 109) nonblind RIND trial in patients new to hemodialysis, data suggest there may be an overall survival benefit with sevelamer versus calcium-based phosphate binder treatment but the evidence on the efficacy of sevelamer in reducing mortality and hospitalization is not strong. The balance of evidence, however, does not strongly support the use of sevelamer over the much less costly calcium-based binders except in patients at risk of hypercalcemic episodes. Further research into cardiovascular and all-cause mortality over a longer time period would be needed to settle this issue, and the relative survival benefits and cost effectiveness of all phosphate binder therapies remains to be fully determined. Despite the relative paucity of data available, sevelamer has established itself as the most widely used binder in the United States and the most widely used noncalcium-based binder worldwide. However, affordability is a major issue for most health economies and in the light of recent economic events is likely to become more prominent.

Calcium and magnesium flux in automated peritoneal dialysis.

BACKGROUND: Calcium and magnesium balance in continuous ambulatory peritoneal dialysis (CAPD) has been extensively studied with several of the different formulations of fluid available. Calcium and magnesium balance in automated PD (APD) is less well studied and the effect on Ca and Mg flux is unknown. Data on glucose polymer solutions are also lacking. This prospective observational study was undertaken to examine mass transfer of Ca and Mg in APD patients. METHODS: 12 patients on APD were studied for two 24-hour periods using, alternately, 1.75 mmol/L and 1.25 mmol/L Ca (Dianeal PD1 and Dianeal PD4; Baxter Healthcare, Newbury, UK) 1.36% glucose-based dialysis fluid for the 9-hour overnight dialysis, followed by a 15-hour daytime dwell of glucose polymer-based fluid (icodextrin). Serum ionized Ca, serum Mg, and dialysate Ca and Mg concentrations were measured at the beginning and end of each period. Mass transfer was calculated as millimoles per exchange. RESULTS: During rapid overnight exchanges with Dianeal PD1 and PD4, mass transfer of Mg and Ca did not show significant correlations with serum levels when using PD1 fluid; however, mass transfer of Mg, but not Ca, was significantly correlated to serum levels when using PD4 fluid. During the long dwell with icodextrin, dialysate drain volume was the most significant factor determining the flux of both Ca and Mg. CONCLUSION: Mass transfer of Ca and Mg in APD patients using conventional dialysis fluid was not related to drain volume in this study, which differs to studies in CAPD. Flux of Ca and Mg during icodextrin use was found to be dependent on ultrafiltration rate and not dialysate or serum concentration.

Oral phosphate binders.

Hyperphosphatemia is an inevitable consequence of end-stage chronic kidney disease and is present in the majority of dialysis patients. Hyperphosphatemia is observationally and statistically associated with increased cardiovascular mortality among dialysis patients. Dietary restriction of phosphate and current dialysis modalities are not sufficiently effective to maintain serum phosphate levels within the recommended range, so the majority of dialysis patients require oral phosphate binders. However, the benefits of achieving the recommended range have yet to be shown prospectively. Unfortunately, conventional phosphate binders are not reliably effective and are associated with a range of limitations and side effects. Aluminum-containing agents are highly efficient but no longer widely used because of proven toxicity. Calcium-based salts are inexpensive, effective, and most widely used, but there is now concern about their association with hypercalcemia and vascular calcification. Sevelamer hydrochloride is associated with fewer adverse effects, but a large pill burden and high cost are limiting factors to its wider use. Lanthanum carbonate is another non-aluminum, calcium-free phosphate binder. Preclinical and clinical studies have shown a good safety profile, and it appears to be well tolerated and effective in reducing phosphate levels in dialysis patients; however, it is similarly expensive. Data on its safety profile over 6 years of treatment are now published. Achievement of opinion-based guidelines appears to have become an end in itself. Dialysis patient outcomes are worse than outcomes for many types of cancer, yet prospective, outcome-based randomized controlled trials are not being undertaken for reasons that are difficult to explain.

Oral phosphate binders for the management of serum phosphate levels in dialysis patients.

Hyperphosphataemia is an inevitable consequence of end stage chronic kidney disease and is present in the majority of dialysis patients. Hyperphosphataemia is statistically associated with increased cardiovascular mortality among dialysis patients. Dietary restriction of phosphate and current dialysis modalities are not sufficiently effective to maintain serum phosphate levels within the recommended range so that the majority of dialysis patients require oral phosphate binders. However, benefits of achieving the recommended range have yet to be demonstrated prospectively. Unfortunately, conventional phosphate binders are not reliably effective and are associated with a range of limitations and side effects. Aluminium containing agents are highly efficient but no longer widely used because of well-established and proven toxicity. Calcium-based salts are inexpensive, effective and most widely used but there is now concern about their association with hypercalcaemia and vascular calcification. Sevelamer hydrochloride and lanthanum carbonate are non-aluminium, calcium-free phosphate binders. They are effective and reasonably well tolerated, but still do not control phosphate levels in all patients. Patient education programmes have been shown to be a useful and effective method of improving achievement of serum phosphate targets.

Iron-magnesium hydroxycarbonate (fermagate): a novel non-calcium-containing phosphate binder for the treatment of hyperphosphatemia in chronic hemodialysis patients.

BACKGROUND AND OBJECTIVES: This phase II study tested the safety and efficacy of fermagate, a calcium-free iron and magnesium hydroxycarbonate binder, for treating hyperphosphatemia in hemodialysis patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A randomized, double-blind, three-arm, parallel-group study compared two doses of fermagate (1 g three times daily or 2 g three times daily with placebo). Sixty-three patients who had been on a stable hemodialysis regimen for > or =3 mo were randomized to the treatment phase. Study medication was administered three times daily just before meals for 21 d. The primary endpoint was reduction in serum phosphate over this period. RESULTS: In the intention-to-treat analysis, mean baseline serum phosphate was 2.16 mmol/L. The fermagate 1- and 2-g three-times-daily treatment arms were associated with statistical reductions in mean serum phosphate to 1.71 and 1.47 mmol/L, respectively. Adverse event (AE) incidence in the 1-g fermagate arm was statistically comparable to the placebo group. The 2-g arm was associated with a statistically higher number of patients reporting AEs than the 1-g arm, particularly gastrointestinal AEs, as well as a higher number of discontinuations, complicating interpretation of this dose's efficacy. Both doses were associated with elevations of prehemodialysis serum magnesium levels. CONCLUSIONS: The efficacy and tolerability of fermagate were dose dependent. Fermagate showed promising efficacy in the treatment of hyperphosphatemia in chronic hemodialysis patients as compared with placebo in this initial phase II study. The optimal balance between efficacy and tolerability needs to be determined from future dose-titration studies, or fixed-dose comparisons of more doses.

Lanthanum and phosphate: science, policy, and survival.

Mineral metabolism in chronic kidney disease is attracting intense interest and unprecedented levels of research. The pharmaceutical industry has responded by developing various new agents. Bervoets et al. report the use of an unusual combination of basic-science techniques to increase understanding of the kinetics of one such agent--lanthanum carbonate--in the gastrointestinal tract and liver. However, do we need to answer more fundamental clinical questions before we can definitively identify the role of similar new and expensive drugs?

Long-term efficacy and safety profile of lanthanum carbonate: results for up to 6 years of treatment.

BACKGROUND/AIMS: Lanthanum carbonate (LC, FOSRENOL) is an effective phosphate binder for which tolerability and a safety profile have been reported in haemodialysis patients. Patients from previous studies entered a 2-year extension, enabling assessment of efficacy and safety for up to 6 years of LC monotherapy. METHODS: Patients from four previous trials entered this study. RESULTS: Ninety-three patients started the extension, with 22 entering a sixth year of LC treatment. Two-thirds of all patients received LC doses of 2,250 or 3,000 mg/day. Reductions in serum phosphate and calcium x phosphate product were maintained for up to 6 years. There were no new or unexpected adverse events (AEs), and no increase in the incidence of events with increasing treatment exposure. Over the complete duration of therapy, treatment-related AEs occurred in 25.8% of patients and were primarily gastrointestinal in nature. No clinically relevant changes in liver function tests were observed and there was no evidence of adverse effects on the liver, bone or the central nervous system. CONCLUSIONS: LC monotherapy was effective and well tolerated for up to 6 years with no evidence of safety concerns or increased frequency of AEs.

Switching to lanthanum carbonate monotherapy provides effective phosphate control with a low tablet burden.

BACKGROUND: Despite recognized risks associated with hyperphosphataemia in patients with chronic kidney disease (CKD) Stage 5 on dialysis, the achievement of target levels of serum phosphate is poor. It is likely that this is partly due to poor adherence by patients to their phosphate-binder treatment regimens, which often comprise large daily tablet burdens. METHODS: In this multicentre, open-label trial, patients on a stable dialysis regimen were screened while receiving phosphate-binder therapy, then entered into a washout phase. Patients with serum phosphate > 1.78 mmol/L after washout entered into the main 12-week treatment phase (N = 367), during which they were treated to target [Kidney Disease Outcomes Quality Initiative (K/DOQI)]: 1.13-1.78 mmol/L; 3.5-5.5 mg/dL) with lanthanum carbonate monotherapy. Efficacy variables included serum phosphate levels and the percentage of patients with serum phosphate control. Safety and tolerability assessments were also conducted. RESULTS: Mean serum phosphate levels were significantly reduced following 12 weeks of lanthanum carbonate monotherapy versus previous phosphate-binder therapy. The mean number of phosphate-binder tablets being taken per day at screening was 7.6, but during treatment with lanthanum carbonate, most patients were taking doses of up to 3000 mg/day, achievable with 3 x 1000 mg tablets per day (maximum of 6). CONCLUSION: These findings suggest that lanthanum carbonate monotherapy offers effective control of serum phosphate and, due to a low tablet burden, may help to simplify the management of hyperphosphataemia in patients with CKD Stage 5.