Is there a need for new phosphate binders to treat phosphate imbalance associated with chronic kidney disease?

Efficacy and safety of PT20, an iron-based phosphate binder, for the treatment of hyperphosphataemia: a randomized, double-blind, placebo-controlled, dose-ranging, Phase IIb study in patients with haemodialysis-dependent chronic kidney disease

BACKGROUND

Hyperphosphataemia is a common complication of chronic kidney disease (CKD). PT20 (ferric iron oxide adipate) is an investigational molecule engineered to offer enhanced phosphate-binding properties relative to other phosphate binders.

METHODS

In this double-blind, parallel-group, placebo-controlled, dose-ranging study (ClinicalTrials.gov identifier NCT02151643), the efficacy and safety of 28 days of oral PT20 treatment were evaluated in patients with dialysis-dependent CKD. Participants were randomly assigned in an 8:8:8:13:13 ratio to receive PT20 (400, 800, 1600 or 3200 mg) or placebo three times daily.

RESULTS

Among 153 participants, 129 completed treatment [7 discontinued because of adverse events (AEs), 2 because of hyperphosphataemia and 15 for other reasons]. PT20 treatment for 28 days resulted in a statistically significant and dose-dependent reduction in serum phosphate concentration. There were no statistically significant effects of PT20 treatment on changes in haemoglobin or ferritin concentrations or transferrin saturation between Days 1 and 29. The incidence of treatment-emergent AEs was broadly similar across the PT20 and placebo groups (42-59% versus 44%). The most common PT20 treatment-related AEs were gastrointestinal, primarily diarrhoea (13-18%) and discoloured faeces (3-23%). No serious AEs were considered to be related to study treatment. There were no clinically significant changes in laboratory results reflecting acid/base status or increases in ferritin that could indicate the absorption of components of PT20.

CONCLUSIONS

In this first study investigating the efficacy and safety of PT20 in patients with hyperphosphataemia and dialysis-dependent CKD, PT20 significantly lowered serum phosphate concentrations and was generally well tolerated.

Cost-Effectiveness of First-Line Sevelamer and Lanthanum versus Calcium-Based Binders for Hyperphosphatemia of Chronic Kidney Disease

BACKGROUND

Phosphate binders are used to treat hyperphosphatemia among patients with chronic kidney disease (CKD).

OBJECTIVES

To conduct an economic evaluation comparing calcium-free binders sevelamer and lanthanum with calcium-based binders for patients with CKD.

METHODS

Effectiveness data were obtained from a recent meta-analysis of randomized trials. Effectiveness was measured as life-years gained and translated to quality-adjusted life-years (QALYs) using utility weights from the literature. A Markov model consisting of non-dialysis-dependent (NDD)-CKD, dialysis-dependent (DD)-CKD, and death was developed to estimate the incremental costs and effects of sevelamer and lanthanum versus those of calcium-based binders. A lifetime horizon was used and both costs and effects were discounted at 1.5%. All costs are presented in 2015 Canadian dollars from the Canadian public payer perspective. Results of probabilistic sensitivity analysis were presented using cost-effectiveness acceptability curves. Sensitivity analyses were conducted for risk pooling methods, omission of dialysis costs, and persistence of drug effects on mortality.

RESULTS

Sevelamer resulted in an incremental cost-effectiveness ratio of $106,522/QALY for NDD-CKD and $133,847/QALY for DD-CKD cohorts. Excluding dialysis costs, sevelamer was cost-effective in the NDD-CKD cohort ($5,847/QALY) and the DD-CKD cohort ($11,178/QALY). Lanthanum was dominated regardless of whether dialysis costs were included.

CONCLUSIONS

Existing evidence does not clearly support the cost-effectiveness of non-calcium-containing phosphate binders (sevelamer and lanthanum) relative to calcium-containing phosphate binders in DD-CKD patients. Our study suggests that sevelamer may be cost-effective before dialysis onset. Because of the remaining uncertainty in several clinically relevant outcomes over time in DD-CKD and NDD-CKD patients, further research is encouraged.

Phosphate binders for the treatment of chronic kidney disease: role of iron oxyhydroxide

Chronic kidney disease-mineral bone disorder is frequent in patients with renal failure. It is characterized by abnormalities in mineral and bone metabolism with resulting hyperphosphatemia, low serum vitamin D, secondary hyperparathyroidism, altered bone morphology and strength, higher risk of bone fractures, and development of vascular or other soft tissue calcifications. Besides the recommendation to reduce phosphorus dietary intake, many drugs are currently available for the treatment of calcium/phosphate imbalance. Among them, phosphate binders represent a milestone. Calcium-based binders (calcium carbonate, calcium acetate) are effective in lowering serum phosphate, but their use has been associated with an increased risk of hypercalcemia and calcifications. Calcium-free binders (sevelamer hydrochloride, sevelamer carbonate, and lanthanum carbonate) are equally or slightly less effective than calcium-containing compounds. They would not induce an increase in calcium levels but may have relevant side effects, including gastrointestinal symptoms for sevelamer and risk of tissue accumulation for lanthanum. Accordingly, new phosphate binders are under investigation and some of them have already been approved. A promising option is sucroferric oxyhydroxide (Velphoro(®), PA21), an iron-based phosphate binder consisting of a mixture of polynuclear iron(III)-oxyhydroxide, sucrose, and starches. The present review is focused on pharmacology, mode of action, and pharmacokinetics of sucroferric oxyhydroxide, with a discussion on comparative efficacy, safety, and tolerability studies of this drug in chronic kidney disease and patient perspectives such as quality of life, satisfaction, and acceptability. Sucroferric oxyhydroxide has proven to be as effective as sevelamer in reducing phosphatemia with a similar safety profile and lower pill burden. Experimental and clinical studies have documented a minimal percentage of iron absorption without inducing toxicity. In conclusion, the overall benefit-risk balance of sucroferric oxyhydroxide is deemed to be positive, and this new drug may therefore represent a good alternative to traditional phosphate binders for the treatment of hyperphosphatemia in dialysis patients.

Novel iron-containing phosphate binders for treatment of hyperphosphatemia

INTRODUCTION

Hyperphosphatemia is a frequent complication of chronic kidney disease and is associated with increased mortality. Despite side effects, risk of accumulation and high costs, phosphate binders (PBs) have become the crucial cornerstone of therapy. The iron-containing PB sucroferric oxyhydroxide (SO) and ferric citrate hydrate (FCH) have entered the market and other candidates are prior market entry.

AREAS COVERED

A literature search was performed using MEDLINE and EMBASE databases to identify references on iron-containing PB with particular regard to efficacy, safety and potential benefits. Additional hand searches were conducted along with a full-text review of any citation that appeared relevant.

EXPERT OPINION

On the highly competitive market, where the 'ideal' PB is still unknown, novel substances that offer clear benefits over available drugs are desired. Although SO and FCH showed similar efficacy and safety compared to sevelamer, head-to-head studies with lanthanum carbonate are absent. Clinical 1-year data in a limited patient cohort suggested improved adherence for SO and a large randomized controlled trial showed significant reduction in hospitalizations and costs for FCH. Additional large randomized controlled trials have now to prove these possible advantages. Cost-effectiveness in comparison to other PB and the exclusion of significant harms under long-term treatment will determine the future use of both drugs.