Cómo estimar la eficacia de un captor del fósforo / How to assess the efficacy of phosphate binders

Antecedentes y objetivos: Es difícil estimar clínicamente la eficacia de los captores de fósforo (CP). Este estudio analiza los cambios que se producen en la fosfatemia y excreción urinaria de fósforo tras la administración de CP a pacientes con enfermedad renal crónica, y la utilidad de la relación entre la excreción urinaria de fósforo y la tasa de catabolismo proteico (Po/TCP) en la estimación de la eficacia de estos fármacos. Métodos: Estudio retrospectivo de observación en una cohorte de pacientes adultos con enfermedad renal crónica en estadios 4-5. Se compararon parámetros bioquímicos basales y 45-60 días después de un tratamiento con dieta baja en fósforo más CP (subgrupo «captor»=260 pacientes) o solo con los consejos dietéticos (subgrupo «control»=79 pacientes). Resultados: La carga de fósforo (excreción urinaria total) por unidad de función renal (Po/GFR) fue el parámetro mejor relacionado con la fosfatemia (R2=0,61). La cifra media de Po/TCP fue de 8,2±2,3mg de fósforo por gramo de proteína. Tras la administración de CP, la fosfatemia descendió un 11%, la fosfaturia un 22%, la tasa de catabolismo proteico un 7% y la Po/TCP un 15%. En el subgrupo control la Po/TCP se incrementó un 20%. La excreción urinaria de fósforo y de nitrógeno ureico se correlacionaron fuertemente de forma lineal antes y después del tratamiento con CP o tras los consejos dietéticos en el subgrupo control. Conclusiones: La Po/TCP es un parámetro que podría reflejar la absorción intestinal de fósforo y, por tanto, sus variaciones tras la administración de CP podrían servir para estimar la eficacia de estos fármacos (AU)

Background and aims: The efficacy of phosphate binders is difficult to be estimated clinically. This study analyzes the changes in serum phosphate and urinary phosphate excretion after the prescription of phosphate binders (PB) in patients with chronic kidney disease stage 4-5 pre-dialysis, and the usefulness of the ratio between total urinary phosphate and protein catabolic rate (Pu/PCR) for estimating the efficacy of PB. Methods: This retrospective observational cohort study included adult chronic kidney disease patients. Biochemical parameters were determined baseline and after 45-60 days on a low phosphate diet plus PB (‘binder’ subgroup=260 patients) or only with dietary advice (‘control’ subgroup=79 patients). Results: Phosphate load (total urinary excretion) per unit of renal function (Pu/GFR) was the best parameter correlated with serum phosphate levels (R2=0.61). Mean±SD level of Pu/PCR was 8.2±2.3mg of urinary phosphate per each g of estimated protein intake. After treatment with PB, serum phosphate levels decreased by 11%, urinary phosphate 22%, protein catabolic rate 7%, and Pu/PCR 15%. In the control subgroup, Pu/PCR increased by 20%. Urinary phosphate and urea nitrogen excretion correlated strongly, both baseline and after PB or dietary advice. Conclusions: The proposed parameter Pu/PCR may reflect the rate of intestinal phosphate absorption, and therefore, its variations after PB prescription may be a useful tool for estimating the pharmacological efficacy of these drugs (AU)

Phosphorus metabolic disorder of Guizhou semi-fine wool sheep.

Guizhou semi-fine wool sheep are affected by a disease, characterized by emaciation, lameness, stiffness in the gait, enlargement of the costochondral junctions, and abnormal curvature in the long bones. The objective of this study was to determine possible relationships between the disease and mineral deficiencies. Samples of tissue and blood were collected from affected and unaffected sheep. Samples of soil and forage were collected from affected and unaffected areas. The samples were used for biochemical analyses and mineral nutrient measurements. Results showed that phosphorus (P) concentrations in forage samples from affected areas were significantly lower than those from unaffected areas (P < 0.01) and the mean ratio of calcium (Ca) to P in the affected forage was 12:1. Meanwhile, P concentrations of blood, bone, tooth, and wool from the affected sheep were also significantly lower than those from the unaffected group (P < 0.01). Serum P levels of the affected animals were much lower than those of the unaffected ones, whereas serum alkaline phosphatase levels from the affected were significantly higher than those from the unaffected (P < 0.01). Inorganic P levels of the affected sheep were about half of those in the control group. Oral administration of disodium hydrogen phosphate prevented and cured the disease. The study clearly demonstrated that the disease of Guizhou semi-fine wool sheep was mainly caused by the P deficiency in forage, as a result of fenced pasture and animal habitat fragmentation.

Captores del fósforo: preferencias de los pacientes en hemodiálisis y su repercusión sobre el cumplimiento del tratamiento y el control del fósforo / Phosphorus binders: preferences of patients on haemodialysis and its impact on treatment compliance and phosphorus control

Introducción: En la actualidad disponemos de un amplio abanico de captores del fósforo (CF), pero sabemos poco acerca de las preferencias de los pacientes y de su repercusión sobre el cumplimiento del tratamiento y el control de los niveles de fósforo. Objetivo: Estudiar las preferencias y creencias de los pacientes respecto a los CF, y su influencia sobre el cumplimiento del tratamiento y el control de los niveles de fósforo. Pacientes y métodos: Estudio observacional transversal. Se incluyeron 121 pacientes que respondieron un cuestionario genérico de cumplimiento del tratamiento (SMAQ) y a un cuestionario específico sobre cumplimiento del tratamiento con CF, tipo de CF preferido y razones de dicha preferencia. Todos los pacientes entrevistados habían probado dos o tres CF. Las consecuencias de la falta de cumplimiento del tratamiento con CF se estimaron indirectamente analizando los valores promedio de fósforo sérico. Resultados: El 40% de los pacientes era incumplidor según el cuestionario SMAQ; se encontró una asociación estadísticamente significativa entre la falta de cumplimiento en general y no alcanzar el objetivo de fósforo sérico promedio <5,5 mg/dl (OR = 4,8; IC 95%, 1,0-6,6; p = 0,02). El 21,4% de los pacientes reconocía un incumplimiento específico para los CF; estos pacientes presentaban una mayor probabilidad de tener cifras medias de fósforo >5,5 mg/dl (OR = 4,7; IC 95%, 1,1-6,5; p = 0,03). Un 43,8% de los pacientes no refirió tener preferencias entre los diferentes tipos de CF; para el resto de pacientes, el CF preferido fue Royen(R), seguido de Fosrenol(R), Renagel(R) y Pepsamar(R). Las razones expresadas para el desagrado con el Renagel® fueron las siguientes: incomodidad en la toma por su gran tamaño (28,8%), necesidad de tomar muchos comprimidos y gran consumo de agua (57,7%) e intolerancia gástrica (13,3%). En el caso del Fosrenol(R) incómodo de tomar (72,7%) e intolerancia gástrica (27,2%); para el Pepsamar(R): mal sabor (54,5%) e intolerancia gástrica (45,4%). Sólo al 9,4% no le gustaba el Royen(R). Al analizar los conocimientos de los pacientes respecto a la utilidad de los CF, un 42% sabía que servían para controlar el fósforo; un 52% no lo sabía y un 6% tenía ideas equivocadas. En cuanto a su importancia: un 47% no conocía por qué son importantes; un 2% tenía ideas erróneas; un 9% creía que era beneficioso para la salud; un 11% creía que era bueno «porque lo dice el medico»; un 26% porque controla el fósforo y un 5% lo relacionaba con el hueso. Ningún paciente relacionó los CF con la enfermedad cardiovascular. Un 24,4% no se llevaba los CF cuando salía fuera de casa o estaba con los amigos; eran pacientes más jóvenes a quienes se les habían prescrito un mayor número de comprimidos de CF y que presentaban un mayor riesgo de no cumplir el objetivo de fósforo (OR = 10,5; IC 95%, -1,8 a -16,4; p <0,001). El porcentaje de pacientes a quienes no les gustaba el CF prescrito fue del 54,5%; dichos pacientes presentaban un mayor riesgo de tener niveles séricos de fósforo >5,5 mg/dl (OR = 13.3; IC 95%, 1,1-1,5; p = 0,0001). Paradójicamente, los pacientes que no cumplían con el tratamiento demostraban un mejor conocimiento de su uso (OR = 17,3; IC 95%, 2,2-10,1; p <0.0001) e importancia (OR = 10,4; IC 95%, 1,5-6,6; p = 0,001). Conclusión: Los pacientes a los que se les habían prescrito CF que no les gustaban tenían un peor control de los niveles de fósforo sérico y se les habían recomendado dosis más altas de los fármacos. El conocimiento de las preferencias de los pacientes acerca de las medicaciones que se les prescriben puede ser un factor esencial para conseguir un mayor cumplimiento del tratamiento y, por ende, lograr mejores resultados en la consecución de los objetivos terapéuticos (AU)

Introduction: Non-adherence to phosphate binding (PB) medication may play a role in the difficulty in achieving the targets for phosphorus. We have a wide spectrum of PB but preferences of patients are poorly understood. Objective: to study the patients’ preferences and beliefs regarding PB and their influence on adherence and serum phosphate. Methods: A cross-sectional cohort study was performed. A total of 121 hemodialysis patients answered a specific questionnaire in which they were questioned about adherence, the type of PB they preferred and the reasons for their choice. All patients questioned tasted two or three PB. The consequence of non-adherence to PB was estimated indirectly by determination of serum phosphorus. Results: Specific noncompliance with PB medication was recognized by 21.4% of patients. Patients non-adherent specifically to PB were more likely to have P levels >5.5 mg/dl (χ2: 4.7; 95% CI 1.07-6.5; p = 0.03). Paradoxically, non-adherent patients showed greater knowledge of the use (χ2: 17.3; 95% CI -2.2-10.1; p <0.0001) and importance of the drug (χ2: 10.4; 95% CI -1.5-6.6; p = 0.001). The percentage of patients prescribed binders that they did not like was 54.5%. Patients who were taking PB that they did not like had a greater risk of having P levels >5.5 mg/dl) (χ2: 13.3; 95% CI -1.1-1.5; p = 0.0001). Calcium acetate was the prefered PB in 47.1% of patients, lanthanum carbonate in 40%, sevelamer in 20.6% and aluminum hydroxide in 19.4%. The reasons claimed by patients for their negative ratings of PB were the type of dosage form, the taste, the number of tablets and gastric intolerance. Gastric intolerance and bad taste were more frequent in aluminum hydroxide patients (19.4% and 22.2%, respectively). Sevelamer received complaints about its dosage form because the tablets were too large and a large number of tablets were required (27.2%). 17.7% of patient who were taking lanthanum carbonate did not like the chewable tablets. Conclusion: patients who were taking binders that they did not like had worse serum P levels and were prescribed higher doses of binders. Knowing patients' preferences about the drugs prescribed may be a key factor in achieving adequate adherence to treatment (AU)

Avances experimentales en metabolismo mineral / No disponible

Uno de los problemas más importantes a los que se enfrentan los nefrólogos es el alto grado de mortalidad cardiovascular de los pacientes en diálisis. Este aumento de la enfermedad cardiovascular se ha asociado a varios factores, pero entre ellos, la hiperfosfatemia brilla con luz propia. Los ni-veles plasmáticos de fósforo considerados normales en estos pacientes se han ido bajando paulatinamente en los últimos años. Por tanto, el control del fósforo en el paciente con enfermedad renal crónica se ha convertido en un retoque ha incentivado la investigación básica en los últimos años. La siguiente revisión pretende reunir los resultados más novedosos presentados en el último año, haciendo énfasis en los métodos de control de la absorción de fósforo, de su eliminación renal y en las calcificaciones vasculares, que son una de las consecuencias directas más graves de la hiperfosfatemia (AU)

One of the most important problems faced by nephrologists is the high degree of cardiovascular mortality in patients on dialysis. This increase in cardiovascular disease has been associated with various factors, but, among them, hyperphosphatemia stands out particularly. The serum phosphate levels considered normal in these patients have gradually decreased in recent years. Therefore, phosphate control in the chronic kidney disease patient has become a challenge that has stimulated basic research in recent years. The aim of the following review is to bring together the most novel results presented in the last year, with emphasis on the methods for control of phosphate absorption, its elimination by the kidneys and vascular calcifications, which are one of the most serious direct consequences of hyperphosphatemia (AU)

Magnesium carbonate is an effective phosphate binder for chronic hemodialysis patients: a pilot study.

OBJECTIVE: This study was designed to evaluate the efficacy of magnesium carbonate as a phosphate binder in hemodialysis patients. DESIGN: This study was a prospective, randomized, open-label trial comparing magnesium carbonate/calcium carbonate versus calcium acetate as a sole phosphate binder. SETTING: This study involved outpatient hemodialysis. PARTICIPANTS: We recruited 30 stable hemodialysis patients without a history of frequent diarrhea. INTERVENTION: After receiving informed consent, we randomized patients 2:1 to magnesium carbonate versus calcium acetate. The dose of each binder was titrated to achieve the Kidney Disease Outcomes Quality Initiative (K/DOQI) phosphate target of <5.5 mg/dL. MAIN OUTCOME MEASURE: The efficacy-phase serum phosphorus concentration and the percentage of patients meeting K-DOQI targets for phosphorus, along with the daily elemental calcium intake, were the primary outcome measures. RESULTS: Magnesium carbonate provided equal control of serum phosphorus (70.6% of the magnebind group and 62.5% of the calcium acetate group had their average serum phosphorus within the K-DOQI target during the efficacy phase), while significantly reducing daily elemental calcium ingestion from phosphate binders (908 +/- 24 vs. 1743 +/- 37 mg/day, P < .0001). CONCLUSION: Magnesium carbonate was generally well-tolerated in this selected patient population, and was effective in controlling serum phosphorus while reducing elemental calcium ingestion.

The role of magnesium binders in chronic kidney disease.

Magnesium is predominantly an intracellular cation that plays a critical role in cellular physiology. Serum levels are often slightly elevated in patients on chronic hemodialysis and older reports suggests that total body stores may also be increased, based on bone biopsies in patients treated with higher dialysate magnesium levels than are currently in use today. Several studies have shown that magnesium, particularly in the form of magnesium carbonate, is an effective phosphate binder and can decrease patients' exposure to calcium. Retrospective studies suggest that magnesium may prevent vascular calcification in dialysis patients, although this remains controversial and has not been evaluated prospectively. Magnesium may reduce arrhythmias postoperatively and, while it may theoretically reduce arrhythmic death in dialysis patients, this hypothesis has never been tested. While short-term or adjuvant use of magnesium carbonate appears safe and effective as a phosphate binder, more studies are needed to evaluate the long-term effects on vascular calcification, bone histology, and mortality.

Practical approaches to management of hyperphosphatemia: can we improve the current situation?

Despite advanced technology and regular and efficient dialysis treatment, the prevalence of hyperphosphatemia still is unacceptably high. Nevertheless, a neutral phosphorus balance level can generally be achieved by optimization of dialysis prescription in combination with individualized dietary and medical strategies. Besides increasing the fraction of inorganic phosphate (iP) removed by convection through the application of hemodiafiltration, extension of daily or weekly treatment time is the most promising way to neutralize phosphorus balance. Dietary phosphate restriction, the second corner stone of phosphate management, bears the risk of development of protein malnutrition. Phosphate binders (PBs) effectively reduce intestinal iP absorption, but are mostly dosed inadequately in relation to meal phosphorus content. Phosphate management may be substantially improved by enabling patients to self-adjust the PB dose to individual meal phosphate content, similar to self-adjusting insulin dose to carbohydrate intake by diabetics. A recently developed Phosphate Education Program (PEP) provides simple training tools to instruct patients to eye-estimate meal phosphorus content based on newly defined phosphorus units instead of milligrams. PEP is the first approach applying the concept of patient empowerment in the management of hyperphosphatemia in dialysis patients.

Efecto hipolipemiante de Sevelamer en el paciente urémico / Hypolipidemic effect of sevelamer in the uremic patient

Antecedentes. Sevelarmer es un quelante de fósforo indicado en el tratamiento de la hiperfosforemia urémica. Estudios recientes reportan un efecto hipolipemiante que añade un valor adicional a esta molécula. Con este estudio pretendemos evaluar el efecto de sevelamer sobre el perfil lipídico y su seguridad. Métodos. Estudiamos de manera retrospectiva pacientes urémicos estables en hemodiálisis. Cada paciente participó con uno o más registros, clasificados en tres grupos según el tratamiento recibido: grupo 1, registro de pacientes tratados con sevelamer durante más de 3 meses; grupo 2, registro de pacientes no tratados con estatina ni sevelamer, y aquellos registro procedentes de pacientes antes de iniciar tratamiento con sevelamer; y grupo 3, registros de pacientes tratados con alguna estatina durante más de 3 meses. Recogimos los efectos adversos achacables a sevelamer. Trimestralmente registramos datos relativos al tratamiento fosfo-cálcico, perfil lipídico sérico, y un amplio perfil de seguridad de laboratorio. Resultados. Los valores medios de colesterol total y colesterol LDL séricos fueron significativamente inferiores en el grupo 1 respecto a los grupos 2 y3. El nivel sérico medio de triglicéridos fue semejante en los tres grupos y la variación en valor absoluto de colesterol HDL medio resultó pequeña. No registramos efectos adversos por sevelamer. El perfil de seguridad de laboratorio fue favorable y semejante en los tres grupos, si bien el valor medio de proteína C reactiva sérica en el grupo 1 fue significativamente inferior respecto a los otros. Conclusiones. Este estudio confirma el valor hipolipemiante de sevelamer en pacientes urémicos y sugiere un perfil pleiotrópico de efectos beneficiosos sobre la enfermedad arteriosclerótica de los pacientes en diálisis

Background. Sevelamer is a phosphorus binder indicated in the treatment of uremic hyperphosphoremia. Recent studies report a hypolipidemic effect adding futher value to this molecule. With this study, we aim to assess the effect of sevelamer on the lipid profile and its safety. Methods. We retrospectively studied stable uremic patients in hemodialysis. Each patient participated with one or more record entries, classified in three groups according to the treatment received: group 1, record entries of patients treated with sevelamer for more than 3 months; group 2, record entries of patients not treated with statin or sevelamer, and those record entries of patients prior to beginning treatment with sevelamer; and group 3, record entries of patients treated with any statin for more than 3 months. Adverse effects attributable to sevelamer were collected. On a quarterly basis, data relating to phosphocalcium treatment, serum lipid profile, and a broad laboratory safety profile were recorded. Results. Mean serum total cholesterol and LDL cholesterol values were significantly lower in group 1 with regard to groups 2 and 3. The mean serum triglyceride level was similar in the three groups, and the change in the mean HDL cholesterol absolute value was minute. No adverse effects due to sevelamer were recorded. The laboratory safety profile was favorable and similar in the three groups, although the mean serum C-reactive protein in group 1 was significantly lower with regard to the other groups. Conclusions. This study confirms the hypolipidemic value of sevelamer in uremic patients and suggests a pleiotropic profile of beneficial effects on arteriosclerotic diseases of patients in dialysis

Lanthanum carbonate.

Controlling hyperphosphatemia in patients with chronic renal failure on renal dialysis is a major problem. None of the available calcium- or aluminum-based phosphate binders match the requirements for an ideal agent, each having its own limitations. The introduction of sevelamer hydrochloride represented a step change in management. Lanthanum carbonate is an alternative nonaluminium, noncalcium phosphate binder. Taken with food, it is well tolerated. It is poorly absorbed and does not require functioning kidneys to be removed from the body. There is no evidence from current studies that it accumulates to biologically significant levels in tissues, but despite the large numbers of patients included in clinical trials, experience with long-term dosing is limited and, as with every new drug used in this type of clinical setting, patients should be carefully monitored as experience with the drug increases. Lanthanum carbonate binds phosphate effectively across the physiological pH range of the upper gastrointestinal tract, and has no detrimental effect on calcium, vitamin D or parathyroid hormone metabolism. From the extensive trial data it seems that lanthanum carbonate is an effective and practical phosphate binder. Lanthanum carbonate and sevelamer are two new oral phosphate binding agents that with others currently in preclinical trials, such as stabilized polynuclear iron idroxide, could well represent a significant breakthrough in the management of hyperphosphatemia in patients with chronic renal failure in whom dietary phosphate restriction and cheaper oral phosphate binding agents prove unsatisfactory. Comparative trials and enhanced clinical experience are needed before the exact place of these competing and complementary therapies can be properly identified in patient management.

The case against calcium-based phosphate binders.

Disturbances of mineral metabolism are associated with significant morbidity and mortality in patients with chronic kidney disease. Unfortunately, some of the treatments for these disturbances also have been found to be associated with morbidity. More recently, there is increasing evidence in the form of prospective, randomized trials that the use of calcium-based phosphate binders contributes to progressive coronary artery and aorta calcification compared with the non-calcium-containing binder sevelamer. Moreover, there is compelling biologic plausibility that hyperphosphatemia and excess exogenous calcium administration can accelerate vascular calcification. Unfortunately, there is no bedside test that can determine whether there is a dose of calcium salts (either as maintenance or as cumulative dose) that can be administered safely, and, unfortunately, the serum calcium concentration does not reflect calcium balance. Therefore, calcium-based phosphate binders should be avoided in many, if not most, patients who are undergoing dialysis.

Calcium-based phosphate binders are appropriate in chronic renal failure.

Many nephrologists feel threatened by the allegation that, in patients with chronic renal failure, treatment with calcium-based phosphate binders (calcium acetate and calcium carbonate) may induce coronary artery and cardiac calcification, thereby imposing a greater risk for death compared with sevelamer, a non-calcium-based binder. Acknowledging that drug manufacturers are not unaware of the marketing advantage to their product consequent to destabilizing demand for competing drugs, the case for and against abandoning calcium-based phosphate binders in favor of sevelamer is reviewed in this study. The case for continuing prescription of calcium-based phosphate binders stands on the following: (1) flawed clinical trials that favor sevelamer as a replacement; (2) weak evidence that oral calcium intake modulates vascular and/or cardiac calcification; (3) clinical trials that reinforce the safety and efficacy of calcium-based phosphate binders; and (4) the inordinate relative cost of sevelamer. Recognizing that established as well as novel phosphate binders are currently undergoing clinical evaluation, an open mind and an awareness of developing literature are necessary when deciding how to manage hyperphosphatemia in renal failure.

Hyperphosphatemia and phosphate binders.

PURPOSE: The pathophysiology of hyperphosphatemia associated with end-stage renal disease and treatment with phosphate binders are discussed. SUMMARY: Phosphorus is an essential element necessary for the normal function of the human body, required for skeletal construction and synthesis of DNA, proteins, and adenosine triphosphate. In healthy individuals, serum phosphorus concentrations are maintained between 2.5 and 4.5 mg/dL through diet and renal excretion. In renal insufficiency, phosphorus excretion declines and hyperphosphatemia develops. The body's compensation mechanisms cause secondary hyperparathyroidism and renal osteodystrophy. Phosphate binders provide an effective means for managing serum phosphate. Commercially available phosphate binders include calcium carbonate, calcium acetate, sevelamer, lanthanum, and, rarely, aluminum hydroxide. Because of aluminum's known toxicities, aluminum-based phosphate binders have a limited place in therapy. Calcium carbonate's benefits are seen over a narrow gastric pH range, thereby limiting the drug's utility. Calcium acetate is effective over a wide pH range. Other phosphate binders, including sevelamer hydrochloride and lanthanum carbonate, have recently entered the market, but their use remains controversial. CONCLUSION: If left untreated, hyperphosphatemia can result in secondary hyperparathyroidism, renal osteodystrophy, and metastatic calcification of blood vessels and soft tissue. The treatment of hyperphosphatemia in patients with chronic renal failure includes dialysis, dietary phosphorus restrictions, phosphate-binding medications, and vitamin D analogs. Selection of phosphate binders should be based on patient characteristics, including serum phosphate, serum calcium, and intact parathyroid hormone concentrations, and patient tolerability.

[Defining the role of sevelamer chloride as a therapeutic agent for management of phosphate in patient with hemodialysis].

It has been about 18 months after the commercial release of sevelamer hydrochloride. I examined the phosphorus management in patient with hemodialysis with the use sevelamer hydrochloride. The phosphorus reduction of sevelamer hydrochloride was weaker than the precipitated calcium carbonate. Patients on artificial dialysis must undergo dietary therapy for the sevelamer hydrochloride to be effective. However, by switching from precipitated calcium carbonate to sevelamer hydrochloride, the calcium level dropped, and as a result the intact PTH rose. It was possible to subdue the rise of intact PTH with vitamin D. The usefulness of vitamin D dramatically increased with the decrease and the eventual cancellation of precipitated calcium carbonate. Furthermore, the calcium load lightened and the product of calcium and phosphorus decreased. At this point, I do not expect substantial phosphorus reduction from sevelamer hydrochloride. It must be recognized that the basis of phosphorus management is proper diet. Only with that can sevelamer hydrochloride be used to its fullest potential.

Blast from the past: the aluminum's ghost on the lanthanum salts.

Hyperphosphatemia is a common serious complication of chronic renal diseases, which needs appropriate continuous treatment in order to avoid ominous side effects. Therefore, oral chelating agents able to avoid phosphate absorption by the gut are mandatory. In the past, Aluminium salts, and more recently Calcium and Magnesium salts, and a synthetic resin polyallylamine hydrochloride have been employed, but Aluminium was later abandoned, because it has been a silent killer of many uremic patients, due to subtle absorption eventually leading to toxicity on Central Nervous System and bone, with allucinations, seizures, dementia, and osteomalacia, bone pain, fracturing osteodystrophy, and death. Recently, a new chelating agent able to bind dietary phosphate, namely Lanthanum carbonate has been introduced, with a proven efficacy profile for short-term treatment. However, after careful examination of the very few scientific papers available to date, we strongly advise caution before adopting, at present, lanthanum carbonate as a phosphate binder in uremic patients. In fact, notwithstanding minimized, some data are worrying: first, Lanthanum ions are absorbed, though at a minimal extent, by human gut; 2) pharmacokinetic evaluations show a greater exposure to Lanthanum in uremic patients;3) Lanthanum concentration is increased tenfold in blood and fivefold in bone after short-term supplementation in uremic patients; 4) there is no proofs that Lanthanum cannot cross the blood brain barrier in uremic patients; 5)Lanthanum has many biological effects and is potentially highly toxic. The Aluminum story should serve as cautionary tale when considering the use of new metal ions.

A long-term, open-label extension study on the safety of treatment with lanthanum carbonate, a new phosphate binder, in patients receiving hemodialysis.

BACKGROUND: Lanthanum carbonate, a new phosphate binder, is effective in reducing serum phosphorus levels in patients with end-stage renal disease. A 1-year extension study to two randomized controlled studies was conducted to evaluate the long-term safety of lanthanum carbonate in patients who received hemodialysis. RESEARCH DESIGN AND METHODS: Patients from two previous lanthanum carbonate studies were eligible to continue treatment in a 1-year open-label extension. A total of 77 patients (N = 77; 11 from Study 1, 66 from Study 2) were enrolled in this extension. The mean age of patients was 60.9 years (SD +/- 12.5 years); 65% were male and 35% were female. All patients received lanthanum carbonate at the optimal dose for phosphorus control, determined in their previous study. Safety and tolerability were assessed by monitoring adverse events, laboratory parameters, and vital signs. The number of patients who maintained serum phosphorus levels at < or = 5.9 mg/dL (1.9 mmol/L) was recorded, along with serum calcium, calcium x phosphorus product, and parathyroid hormone levels. RESULTS: Lanthanum carbonate was well tolerated and was associated with few treatment-related adverse events. The most commonly reported adverse events were nausea (26.0%), peripheral edema (23.4%), and myalgia (20.8%). No treatment-related serious adverse events occurred. By Week 4, the mean serum phosphorus level had decreased by approximately 1 mg/dL to 5.7 +/- 2.0 mg/dL (1.84 +/- 0.7 mmol/L). At the end of the study, the mean pre-dialysis serum phosphorus level was 5.7 +/- 1.4 mg/dL (1.84 +/- 0.5 mmol/L); 53% of patients had controlled phosphorus levels. Calcium x phosphorus product decreased during Week 1 and remained within a clinically acceptable range thereafter. There were no clinically significant changes in serum calcium, or parathyroid hormone levels. CONCLUSION: Lanthanum carbonate is well tolerated and is effective for the long-term maintenance of serum phosphorus control in patients with end-stage renal disease.

Lanthanum carbonate for the treatment of hyperphosphataemia in renal failure and dialysis patients.

Hyperphosphataemia is a usual accompaniment of end stage renal disease and dialysis, in the absence of dietary phosphate restriction or supplemental phosphate binders. It is associated with renal osteodystrophy, metastatic calcification and increased mortality and morbidity. Despite dietary restriction and dialysis, most patients will require a phosphate-binding agent to treat this condition. However, phosphate control has not significantly improved over the last two decades, mainly because of the lack of an ideal oral phosphate-binding agent. Aluminium- and calcium-based agents are associated with major side effects, despite their undoubted efficacy. Although sevel-amer hydrochloride represents a step forward in the management of hyperphosphataemia, it is not an ideal phosphate binder due to its cost and tablet burden. Lanthanum carbonate is the most recent non-calcium, non-aluminium, phosphate-binding agent. It is effective and well-tolerated, and no negative effects on bone histology have been observed.

Effect of MCI-196 (colestilan) as a phosphate binder on hyperphosphataemia in aemodialysis patients: a double-blind, placebo-controlled, short-term trial.

BACKGROUND: MCI-196 (colestilan), an anion exchange resin, is widely used as an anti-hypercholesterolaemic drug in Japan. To evaluate the efficacy and safety of MCI-196 as a phosphate binder, a double-blind, randomized, placebo-controlled prospective trial was conducted in Japanese end-stage renal disease patients with hyperphosphataemia on intermittent haemodialysis treatment. METHODS: Phosphate binders were discontinued during a 2-week washout period. Subsequently, patients whose serum phosphorus levels were > or =6.5 mg/dl, but <10 mg/dl were eligible to enter the treatment protocol. Patients were randomized to either MCI-196 6 g/day or placebo for 2 weeks. The efficacy and safety of MCI-196 were assessed in 33 and 46 patients, respectively. RESULTS: Serum phosphorus in the placebo group increased by 0.84+/-0.95 mg/dl (mean+/-SD), while serum phosphorus in the MCI-196 group decreased by 0.55+/-1.23 mg/dl. The difference between the two groups was statistically significant (P = 0.002). A reduction of > or =1 mg/dl in serum phosphorus was observed in 43% in the MCI-196 group and 0% of patients in the placebo group (P = 0.0122). Calcium-phosphorus (Ca x P) product, intact parathyroid hormone (iPTH) and low-density lipoprotein (LDL)-cholesterol in the MCI-196 group also decreased significantly compared with the placebo group, while serum calcium was unchanged. Adverse reactions were observed in 51.7% of the MCI-196 group and 29.4% of the placebo group (P = 0.2186). The most frequent adverse reactions in the MCI-196 group were gastrointestinal symptoms and signs, including constipation. CONCLUSIONS: The present findings suggest that the short-term administration of MCI-196 is effective in decreasing serum phosphorus in haemodialysis patients. Its long-term efficacy needs to be evaluated.

Phosphorus management in end-stage renal disease.

Chronic kidney disease is an important public health problem, with an increasing number of patients worldwide. One important outcome of renal failure is disordered mineral metabolism, most notably involving calcium and phosphorus balance. Of importance is that increased serum phosphorus levels are associated with increased mortality rates. Despite dietary restrictions, patients receiving dialysis invariably experience hyperphosphatemia and require treatment with phosphate binders. Existing phosphate binders are effective in reducing serum phosphorus levels, but are associated with a number of important disadvantages. Lanthanum carbonate, a new noncalcium, nonaluminum phosphate binder, represents a promising treatment for hyperphosphatemia.