Cinacalcet Hydrochloride (Sensipar) in Hemodialysis Patients on Active Vitamin D Derivatives with Controlled PTH and Elevated Calcium × Phosphate

Recommendations of the Spanish Society of Nephrology for the management of mineral and bone metabolism disorders in patients with chronic kidney disease: 2021 (SEN-MM)

As in 2011, when the Spanish Society of Nephrology (SEN) published the Spanish adaptation to the Kidney Disease: Improving Global Outcomes (KDIGO) universal Guideline on Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD), this document contains an update and an adaptation of the 2017 KDIGO guidelines to our setting. In this field, as in many other areas of nephrology, it has been impossible to irrefutably answer many questions, which remain pending. However, there is no doubt that the close relationship between the CKD-MBD/cardiovascular disease/morbidity and mortality complex and new randomised clinical trials in some areas and the development of new drugs have yielded significant advances in this field and created the need for this update. We would therefore highlight the slight divergences that we propose in the ideal objectives for biochemical abnormalities in the CKD-MBD complex compared to the KDIGO suggestions (for example, in relation to parathyroid hormone or phosphate), the role of native vitamin D and analogues in the control of secondary hyperparathyroidism and the contribution of new phosphate binders and calcimimetics. Attention should also be drawn to the adoption of important new developments in the diagnosis of bone abnormalities in patients with kidney disease and to the need to be more proactive in treating them. In any event, the current speed at which innovations are taking place, while perhaps slower than we might like, globally drives the need for more frequent updates (for example, through Nefrología al día).

The effect of evocalcet on vagus nerve activity of the gastrointestinal tract in miniature pigs

Evocalcet is a novel calcimimetic agent with fewer gastrointestinal (GI) adverse effects compared to cinacalcet. Although it is thought that cinacalcet induces GI side effects through the direct stimulation of the calcium receptor (CaR) expressed in the GI tract, the differences in the direct stimulatory effects of these two drugs on the GI tract have not been reported. In this study, we analyzed the difference in the GI effects of these two calcimimetic agents using miniature pigs by detecting vagus nerve stimulation after oral administration of the agents. Although cinacalcet induced vomiting in miniature pigs, evocalcet never induced emetic symptoms. A significant increase in the vagus nerve action potentials was observed after the administration of cinacalcet. Although the increase of that after the administration of evocalcet was mild and not significant in comparison to that in the vehicle group, it was not significantly different from the vagus nerve action potentials after cinacalcet treatment.

Three Therapeutic Strategies: Cinacalcet, Paricalcitol or Both in Secondary Hyperparathyroidism Treatment in Hemodialysed Patients During 1-Year Observational Study-A Comparison

Introduction: Secondary hyperparathyroidism (sHPT) is a common hormonal complication of chronic kidney disease. There are several therapeutic options for sHPT management aiming at calcium-phosphorus balance normalization and decrease of parathormone secretion. Objectives: The aim of this retrospective, observational study was the outcome assessement of three most common therapeutic strategies of secondary hyperparathyroidism treatment with vitamin D receptor activator-paricalcitol, calcimimetic-cinacalcet or both agents administered together during in 12-months period. Methods: One hundred and thirty-one haemodialysed patients with uncontrolled parathyroid hormone secretion have been treated with paricalcitol administered intravenously (group PAR-60 patients) or cinacalcet per os (group CIN-50 patients). The last group (group PAR+CIN-21 patients) received paricalcitol i.v. and oral cinacalcet administered simultaneously. Results: In all groups, the iPTH level decreased significantly, however in group 1 treated with paricalcitol administered intravenously iPTH level decrease was greater than in group 2 treated with cinacalcet and in group 3 treated with paricalcitol and cinacalcet in parallel. The most substantial change of iPTH level was noticed after 3-months of observation. After this period the iPTH level was stabilized and maintained till the end of observation. Safety level of all strategies was comparable. No severe hypercalcemia or hypocalcemia was observed during the whole period of observation. Conclusions: The results of observation show significant advantage of intravenous paricalcitol treatment. Complementing cinacalcet therapy with paricalcitol does not improve treatment outcomes. In case of unsatisfactory results after 3-months treatment, potential continuation should be considered carefully. Among three available therapeutic options, the treatment with paricalcitol i.v. should be considered in all haemodialysed patients with inadequate control of serum PTH level. The second option-with cinacalced administered orally should be considered in PD patients and when severe hypercalcemia occurs.

Overview of the 2017 KDIGO CKD-MBD Update: Practice Implications for Adult Hemodialysis Patients

Renal dietitians play a pivotal role in the ongoing management of chronic kidney disease in patients on hemodialysis. Awareness of changes to clinical practice guidelines that may impact laboratory parameters associated with chronic kidney disease-mineral and bone disorder is important for optimal patient care. In this article, the Kidney Disease: Improving Global Outcomes 2017 Clinical Practice Guideline Update recommendations related to the treatment of secondary hyperparathyroidism in adults on hemodialysis are reviewed and treatment implications for renal dietitians discussed. Specific attention is given to the integration of updated recommendations such as the use of calcimimetics as part of a combination approach to the existing treatment paradigm. Renal dietitians can directly apply the updated clinical recommendations in the evaluation of diet composition; food additives; medication adherence challenges with phosphate binder type and use and serial monitoring of phosphorus, calcium, and parathyroid hormone levels to inform clinical decisions on treatment options for patients.

Case report: Electron microscopic evaluation of bone from a patient treated with cinacalcet hydrochloride, maxacalcitol, and alfacalcidol for hyperparathyroid bone disease with secondary hyperparathyroidism

Evaluation of bone is of great importance in chronic kidney disease patients, as these patients are at an increased risk for fractures. We treated a hemodialysis patient suffering from hyperparathyroid bone disease with cinacalcet hydrochloride and concurrent administration of maxacalcitol and alfacalcidol for a year. Hyperparathyroid bone disease is characterized by cortical thinning, increased cortical porosity, reduced trabecular bone volume, and increased hypomineralized matrix volume, and there is little information to date about the effects of treatment with cinacalcet hydrochloride on the bone fragility in patients with hyperparathyroid bone disease. In the present study, histological and backscattered electron microscopic evaluation of this combination treatment revealed an excellent improvement of both bone volume and bone morphology. This treatment improved cortical thinning, cortical porosity, and trabecular thinning. Furthermore, the treatment also reduced hypomineralized matrix volume, indicative of improved mineralization by osteocytes. We speculate that the intermittent maxacalcitol administration may have effectively stimulated the vitamin D receptors expressed on osteocytes and osteoblasts, resulting in increased mineralization. Our approach for evaluating the bone in patients with chronic kidney disease by backscattered electron microscopy is novel.

Cholecalciferol Additively Reduces Serum Parathyroid Hormone Levels in Severe Secondary Hyperparathyroidism Treated with Calcitriol and Cinacalcet among Hemodialysis Patients

We evaluated the improvement of intact parathyroid hormone (iPTH) levels and bone parameters by supplementing nutritional vitamin D (cholecalciferol) to combined calcimimetic (cinacalcet) and active vitamin D analog (calcitriol) among severe secondary hyperparathyroidism (SHPT) hemodialysis (HD) patients. A randomized, controlled open-label study was undertaken in 60 HD patients with serum iPTH > 1000 pg/mL or persistently high iPTH ≥ 600 pg/mL even after >3 months of calcitriol (3 μg/week). The study group received oral cholecalciferol (5000 IU/ day) and the control group received a placebo. All patients received fixed dose cinacalcet (30 mg/day, orally) and calcitriol. Calcitriol was reduced if iPTH ≤ 300 pg/mL and cinacalcet was withdrawn if serum iPTH was persistently low (iPTH ≤ 300 pg/mL) for 4 weeks after the reduction of calcitriol. A significantly lower iPTH level was noted from the 20th week in the study group compared to the placebo group, and the target iPTH ≤ 300 pg/mL was achieved at the 24th week in the study group. Most patients achieved serum 25-(OH)D₃ ≥ 30 ng/mL in the study group. Nearly 40% of study patients gained >10% improvement in femoral neck (FN) bone mineral density (BMD). We conclude that cholecalciferol additively reduced serum iPTH levels, improved 25-(OH)D₃ levels and improved FN BMD when used together with cinacalcet/calcitriol in severe SHPT HD patients.

Mortality in dialysis patients with cinacalcet use: A large observational registry study

BACKGROUND

Secondary hyperparathyroidism (sHPT) is associated with higher mortality in dialysis patients. The calcimimetic cinacalcet reduces intact parathyroid hormone (iPTH) in dialysis patients. The randomized controlled EVOLVE trial failed to unequivocally prove survival advantage of cinacalcet in dialysis patients. However, recent post hoc analyses suggested a benefit in subgroups of dialysis patients. Large observational cohort studies may represent an option to better determine such subgroups.

METHODS

Data from the nationwide Austrian registry of dialysis patients between January 2004 and December 2009 were analyzed with follow-up until December 2010. All-cause and cardiovascular mortality analyses were performed using the Kaplan-Meier and Cox proportional hazards regression. To reduce confounding effects a propensity score (PS) based method (matching by stratification) was used for group comparison.

RESULTS

The cohort included 7983 dialysis patients, 1572 (19.7%) were prescribed cinacalcet. During a median follow-up of 2.7years, 3574 (44.8%) patients died, including 1342 (16.8%) deaths from cardiovascular causes. Survival analyses in the PS-matched study population (n=6109) showed lower all-cause mortality for cinacalcet-treated as compared to untreated patients only in subsets characterized by younger age, low prevalence of diabetes, iPTH levels between 300 and 599pg/mL, concomitant therapy with vitamin D and phosphate binders.

CONCLUSIONS

Our data suggest that a subgroup of dialysis patients, namely those with moderate sHPT, younger age and without diabetes benefit from cinacalcet with reduced overall and cardiovascular mortality. These findings may help to identify populations for further controlled trials and may allow a more individualized sHPT treatment using cinacalcet in specific patient subgroups.

Clinical and Practical Use of Calcimimetics in Dialysis Patients With Secondary Hyperparathyroidism

CKD and CKD-related mineral and bone disorders (CKD-MBDs) are associated with high cardiovascular and mortality risks. In randomized clinical trials (RCTs), no single drug intervention has been shown to reduce the high mortality risk in dialysis patients, but several robust secondary analyses point toward important potential beneficial effects of controlling CKD-MBD-related factors and secondary hyperparathyroidism. The advent of cinacalcet, which has a unique mode of action at the calcium-sensing receptor, represented an important step forward in controlling CKD-MBD. In addition, new RCTs have conclusively shown that cinacalcet improves achievement of target levels for all of the metabolic abnormalities associated with CKD-MBD and may also attenuate the progression of vascular and valvular calcifications in dialysis patients. However, a final conclusion on the effect of cinacalcet on hard outcomes remains elusive. Tolerance of cinacalcet is limited by frequent secondary side effects such as nausea, vomiting, hypocalcemia and oversuppression of parathyroid hormone, which may cause some management difficulties, especially for those lacking experience with the drug. Against this background, this review aims to summarize the results of studies on cinacalcet, up to and including the publication of the recent ADVANCE and EVOLVE RCTs, as well as recent post hoc analyses, and to offer practical guidance on how to improve the clinical management of the most frequent adverse events associated with cinacalcet, based on both currently available information and personal experience. In addition, attention is drawn to less common secondary effects of cinacalcet treatment and advisable precautions.

Efficacy of early treatment with calcimimetics in combination with reduced doses of vitamin d sterols in dialysis patients

Vitamin D is an important physiologic regulator of bone and mineral metabolism. In chronic kidney disease, reduced renal production of calcitriol contributes to secondary hyperparathyroidism (SHPT). Consequently, supplementation with vitamin D sterols is an important treatment for SHPT and its associated mineral and bone disorders. However, doses of vitamin D sterols required to suppress parathyroid hormone (PTH) secretion often promote hypercalcaemia and hyperphosphataemia. Therefore, there is a trade-off between reduced serum PTH and increased levels of serum calcium, phosphorus and calcium–phosphorus product. It has been suggested that treatment of SHPT with cinacalcet, a type II calcimimetic, with reduced doses of vitamin D sterols could enhance achievement of calcium and phosphorus treatment targets while maintaining goals for PTH. Recent clinical trials have evaluated this hypothesis and demonstrated that treatment with cinacalcet in combination with reduced doses of vitamin D sterols is an effective treatment for the management of SHPT.

Long-term prognosis of parathyroid function in chronic dialysis patients after PEIT-a single-centre trial

Background. Secondary hyperparathyroidism (SHPT) is a common complication observed in long-term dialysis patients. Percutaneous ethanol injection therapy (PEIT) of parathyroid glands (PTGs) is now established in Japan as a treatment option for SHPT. In this study, to elucidate the factors influencing efficacy in 1 year and relapse following PEIT, we analysed the long-term prognosis of parathyroid function that is known to have the greatest effect on therapeutic results.

Methods. The study design was a retrospective cohort study. We studied 104 patients with SHPT, who underwent PEIT at Tokai University Hospital between January 1993 and December 2002, and we followed them up until January 2008. The effective group reached intact parathyroid hormone of 200 pg/ml or less, corrected calcium (Ca) of 10.5 mg/dl or less and phosphate (P) of 6.0 mg/dl or less. The ineffective group failed to achieve these criteria.

Results. Among the 104 patients, 66 patients (63%) fulfilled the criteria for the effective group within the first year of PEIT. Using the multivariate logistic regression analysis, the number of PTGs before PEIT was a significant risk factor to deviate from the criteria. At the end of the surveillance period, 31 patients (30%) fulfilled the criteria, and their SHPT was controlled with PEIT. Using the multivariate logistic regression analysis, more than three PTGs at the beginning, and the increase in PTGs during the observation period were significant risk factors to deviate from the criteria. In conclusion, superior results with PEIT are obtained in terms of efficacy, remission period and risk of relapse, regardless of the size of the gland.

A Randomized Trial of Cinacalcet versus Vitamin D Analogs as Monotherapy in Secondary Hyperparathyroidism (PARADIGM)

BACKGROUND AND OBJECTIVES

Direct comparison of cinacalcet and vitamin D analogs as monotherapies to lower parathyroid hormone (PTH) levels has not been undertaken.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a prospective, multicenter, phase 4, randomized, open-label study that enrolled participants from 2010 to 2012. Adult participants (n=312) on hemodialysis with PTH >450 pg/ml were randomized 1:1 to 12 months of treatment with either cinacalcet (n=155) or vitamin D analogs (n=157) to evaluate the mean percentage change in plasma PTH level (primary end point) and the proportion of participants achieving plasma PTH <300 pg/ml or a ≥30% decrease in PTH (secondary end points). A preplanned analysis to determine whether there were important region-by-treatment interactions was also undertaken.

RESULTS

Baseline mean PTH was 846 pg/ml (n=155) for cinacalcet and 816 pg/ml (n=157) for vitamin D analog therapy. The mean (95% confidence interval) percentage change from baseline in PTH was -12.1% (-20.0% to -4.1%) in the cinacalcet arm and -7.0% (-14.9% to 0.8%) in the vitamin D analog arm, a difference of -5.0% (-15.4% to 5.4%) (P=0.35). Similarly, there was no difference in achievement of secondary efficacy end points between arms (19.4% and 15.3% of participants with PTH≤300 pg/ml and 42.6% and 33.8% of participants had a PTH reduction >30% in the cinacalcet and vitamin D analog arms, respectively). A prespecified analysis revealed a large treatment-by-region interaction, with nominally greater response to cinacalcet compared with vitamin D analogs in non-United States participants (US versus non-US participants, P<0.001). Hypocalcemia was more common in the cinacalcet arm, whereas hypercalcemia and hyperphosphatemia occurred more often in the vitamin D analog arm.

CONCLUSIONS

Participants had similar modest reductions in PTH with either cinacalcet or vitamin D analog monotherapy over 52 weeks of treatment, but effects varied by region. Treatments differed with regard to effect on calcium and phosphorus levels.

Calcimimetics for secondary hyperparathyroidism in chronic kidney disease patients

BACKGROUND

Calcimimetic agents lower abnormal serum parathyroid hormone (PTH) levels in people who have chronic kidney disease (CKD), but the benefits and harms on patient-level outcomes are uncertain. Since this review was first published in 2006 showing that evidence for calcimimetics was largely restricted to biochemical outcomes, additional studies have been conducted. This is an update of a review first published in 2006.

OBJECTIVES

To evaluate the benefits and harms of cinacalcet on patient-level outcomes in adults with CKD.

SEARCH METHODS

MEDLINE, EMBASE, CENTRAL and conference proceedings were searched for randomised controlled trials (RCTs) evaluating any calcimimetic against placebo or another agent in adults with CKD (persistent albuminuria > 30 mg/g with or without reduced glomerular filtration rate (GFR) (below 60 mL/min/1.73 m²)). We updated searches to 7 February 2013 including the Cochrane Renal Group's Specialised Register to complete this update.

SELECTION CRITERIA

We included all RCTs of a calcimimetic administered to patients with CKD for the treatment of elevated serum PTH levels.

DATA COLLECTION AND ANALYSIS

Data were extracted on all relevant patient-centred and surrogate outcomes. We summarised treatment estimates using random effects and expressed treatment effects as a risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

Eighteen studies (7446 participants) compared cinacalcet in addition to standard therapy with no treatment or placebo plus standard therapy. In adults with GFR category G5 (GFR below 15 mL/min/1.73 m²) treated with dialysis, routine cinacalcet treatment had little or no effect on all-cause mortality (RR 0.97, 95% CI 0.89 to 1.05), imprecise effects on cardiovascular mortality (RR 0.67, 95% CI 0.16 to 2.87), and prevented surgical parathyroidectomy (RR 0.49, 95% CI 0.40 to 0.59) and hypercalcaemia (RR 0.23, 95% CI 0.05 to 0.97), but increased hypocalcaemia (RR 6.98, 95% CI 5.10 to 9.53), nausea (RR 2.02, 95% CI 1.45 to 2.81) and vomiting (RR 1.97, 95% CI 95% CI 1.73 to 2.24). Cinacalcet decreased serum PTH (MD -281.39 pg/mL, 95% CI -325.84 to -234.94) and calcium (MD -0.87 mg/dL, 95% CI -0.96 to -0.77) levels, but had little or no effect on serum phosphorous levels (MD -0.23 mg/dL, 95% CI -0.58 to 0.12).Data were sparse for adults with GFR categories G3a to G4 (GFR 15 to 60 mL/min/1.73 m²) and kidney transplant recipients.Overall, based on GRADE criteria, evidence for cinacalcet in adults with GFR category G5 treated with dialysis (mortality, parathyroidectomy, hypocalcaemia, and nausea) is of high or moderate quality. High quality evidence suggests "further research is very unlikely to change our confidence in the estimate of treatment effect" and moderate quality evidence is "further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate". Information for adults with less severe CKD GFR category G3a to G4 is of low or very low quality. This means that further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate

AUTHORS' CONCLUSIONS

Routine cinacalcet therapy reduced the need for parathyroidectomy in adults treated with dialysis and elevated PTH levels but does not improve all-cause or cardiovascular mortality. Cinacalcet increases risks of nausea, vomiting and hypocalcaemia, suggesting harms may outweigh benefits in this population.

Long-Term Hypoparathyroidism and Hypophosphatemia in Dialysis Patients

Background and Objectives. Hypoparathyroidism in patients with functioning kidneys leads to hyperphosphatemia. This article reviews data suggesting that hypoparathyroidism in patients on dialysis leads to hypophosphatemia. Design. Clinical data of the following were reviewed: (a) a patient with hypoparathyroidism before and during chronic dialysis; (b) patients on dialysis with surgically created hypoparathyroidism; (c) dialysis patients being treated with Cinacalcet, a calcium-sensing receptor agonist that lowers parathyroid hormone (PTH) levels; and (d) dialysis patients being treated with Velcalcetide, a new calcium-sensing receptor agonist that also lowers PTH. Results. In the patient presented in this study, in patients with surgically created hypoparathyroidism, and those receiving Cinacalcet or Velcalcetide, a fall in PTH was associated with hypophosphatemia or a fall in serum phosphorus. Conclusion. In patients on dialysis, hypoparathyroidism may lead to hypophosphatemia.

Pharmacodynamics of cinacalcet over 48 hours in patients with controlled secondary hyperparathyroidism: useful data in clinical practice

CONTEXT

Cinacalcet induces immediate changes in serum PTH levels, but the pharmacodynamic effect throughout the daily dosing interval in controlled patients is unknown. Also, in patients with reduced PTH, it is unknown what happens in the first 24 hours after withdrawal.

OBJECTIVE

Our aim was to describe the effect over 48 hours of cinacalcet in hemodialysis patients with controlled secondary hyperparathyroidism.

DESIGN

This was a phase 4, open-label, single-arm, single-dose, single-center clinical trial.

SETTING

The study was conducted at a public hospital (Hospital Perpetuo Socorro, Alicante, Spain).

PATIENTS

We included 10 patients on cinacalcet for 6 months or longer with intact PTH (iPTH) levels 100-400 pg/mL [8 men, mean age of 66 years (range 39-82 years)], chronically treated with 30 mg (n = 6), 60 mg (n = 3), or 90 mg (n = 1) of cinacalcet.

INTERVENTION

A single dose (30-90 mg) was administered at baseline.

MAIN OUTCOME MEASURES

iPTH (Duo Kit Scantibodies and Elecsys Roche), PTH 1-84, ionized calcium, phosphorus (P), and calcitonin were determined at baseline and at 1, 3, 6, 12, 24, and 48 hours.

RESULTS

There was a significant reduction in iPTH between 1 and 6 hours, and values returned to baseline at 24 hours [maximum mean (95% confidence interval) percent change from baseline: -50%(-34; -66) at 3 hours]. A transient increase in calcitonin and a decrease in P were also observed, with no changes in calcium. At 48 hours, there was a significant increase in iPTH [+51% (26; 76)] and P. Changes in PTH were similar with the 3 determination methods.

CONCLUSIONS

In hemodialysis patients with secondary hyperparathyroidism controlled by cinacalcet, a transient (1-6 hours) reduction in PTH and P and an increase in calcitonin are observed after each daily dose, with return to baseline at 24 hours. After calcimimetics discontinuation, PTH was significantly increased at 48 hours. The assay used to measure PTH does not influence relative changes induced by cinacalcet.

Efficacy of cinacalcet with low-dose vitamin D in incident haemodialysis subjects with secondary hyperparathyroidism

BACKGROUND

Treatment with cinacalcet improves the control of secondary hyperparathyroidism (SHPT) and the achievement of calcium and phosphorus targets. Most data come from subjects receiving cinacalcet after several years of dialysis treatment. We therefore compared the efficacy of treatment with cinacalcet and low doses of active vitamin D to flexible doses of active vitamin D alone for the management of SHPT in patients recently initiating haemodialysis.

METHODS

This open-label trial randomized subjects (n = 309) with parathyroid hormone (PTH) >300 pg/mL on dialysis for 3-12 months to either cinacalcet with low-dose active vitamin D, if prescribed (cinacalcet); or usual care without cinacalcet (control). Randomized subjects were stratified by PTH at screening (300-450, >450-600, >600 pg/mL) and by the use of active vitamin D at enrolment. Treatment duration was 12 months, with primary efficacy endpoint (mean PTH reduction ≥ 30% from baseline) assessed at 6 months.

RESULTS

The mean [standard deviation (SD)] haemodialysis vintage at enrolment was 7.2 (2.7) months; 53% of subjects were not receiving active vitamin D at enrolment. There was a significant difference in the achievement of the primary endpoint (≥ 30% PTH reduction at 6 months) between cinacalcet-treated subjects and controls in both the entire cohort (63 versus 38%; n = 304; P < 0.0001) and the subgroup of subjects not receiving active vitamin D at enrolment (70 versus 44%; n = 161; P < 0.01). Hypocalcaemia and gastrointestinal adverse events were more commonly observed in cinacalcet-treated subjects.

CONCLUSIONS

These results indicate that cinacalcet with low-dose active vitamin D, if prescribed, provides a more effective treatment approach than usual care without cinacalcet for SHPT in incident haemodialysis patients, even in relatively treatment-naive patients.

An open-label study to evaluate a single-dose of cinacalcet in pediatric dialysis subjects

BACKGROUND

There is limited knowledge of the effectiveness and safety profile of cinacalcet in pediatric patients with secondary hyperparathyroidism (sHPT) treated with dialysis.

METHODS

This was an open-label, single-dose study conducted on 12 pediatric subjects with chronic kidney disease treated with dialysis. Subjects were stratified by four age cohorts and given a single 15-mg oral dose of cinacalcet. Multiple blood samples were collected up to 72 h post-dose for the assessment of serum calcium (Ca), serum intact parathyroid hormone (iPTH), and plasma cinacalcet concentrations.

RESULTS

Overall, cinacalcet was well tolerated with no serious adverse events. Mean (standard deviation) percentage change in serum Ca over the first 12 h post-dose was -2.93 % (5.70 %) with a nadir of -4.34 % (6.04 %) at 8 h; Ca values returned to baseline by 48 h post-dose. Mean percentage change in iPTH over the first 12 h post-dose was 57.94 % (71.82 %) with a nadir of -35.65 % (55.82 %) at 2 h. There was an inverse relationship between peak serum Ca concentration and body surface area (BSA) (r (2) = 0.41), although no relationship was found between area under the curve and age or BSA.

CONCLUSIONS

These data support future analysis to determine the therapeutic starting dose of cinacalcet for pediatric patients with sHPT on dialysis.

Hyperphosphatemia - The Risk Factor for Adverse Outcome in Maintenance Hemodialysis Patients

Hyperphosphatemia is a potent stimulator of vascular and valvular calcifications in hemodialysis patients. To determine the prevalence of hyperphosphatemia and assess its effect on the outcome of hemodialysis patients, a total of 115 chronic hemodialysis patients were studied. Laboratory parameters were determined at baseline, and after 12 and 24 months of follow-up. Valvular calcification was assessed with echocardiography. Laboratory parameters were statistically analyzed with ANOVA. Survival analysis was performed with the Kaplan-Meier test and Log-Rank test. Hyperphosphatemia was present in 31.30% of the patients, high calcium-phosphate (Ca × P) product in 36.52% and valvular calcifications in 48.70%. Patients with serum phosphate >2.10 mmol/L and Ca × P product >5.65 mmol2/L2at baseline were at high risk for all-cause and cardiovascular mortality. Hyperphosphatemia is a risk factor for adverse outcome in patients on regular hemodialysis.

Cinacalcet hydrochloride therapy for secondary hyperparathyroidism in hemodialysis patients

This study compared the efficacy of a cinacalcet-based regimen with unrestricted conventional therapy (vitamin D and phosphate binders) for achieving Kidney Disease Outcome Quality Initiative (K/DOQI) targets for dialysis patients. In this multicenter, prospective study, hemodialysis patients with poorly controlled secondary hyperparathyroidism (SHPT) were randomized to receive a cinacalcet-based regimen (n=55) or a conventional therapy (n=27). Doses of cinacalcet, vitamin D sterols, and phosphate binders were adjusted during a 12-week dose-titration phase to achieve intact parathyroid hormone (iPTH) levels ≤ 31.8 pmol/L. The primary end point was the percentage of patients with values in this range during a 24-week efficacy-assessment phase. The clinical response to 36-week cinacalcet treatment was evaluated. A dual energy X-ray absorptiometry was performed before and after 36 weeks of cinacalcet therapy. Fifty-eight percent of the cinacalcet group reached the primary end point, as compared with 19% of the conventional therapy group (P=0.001). A higher percentage of patients receiving the cinacalcet-based regimen versus conventional therapy achieved the targets for calcium, phosphorus and Ca×P. Achievement of targets was greatest in patients with less severe disease (intact PTH range, 31.8 to 53 pmol/L). Cinacalcet therapy increased proximal femur bone mineral density (BMD), but did not affect the lumbar spine. Itching intensity decreased significantly. Cinacalcet based treatment facilitates achievement of the K/DOQI targets for iPTH and bone mineral metabolism compared with conventional therapy in hemodialysis patients. Suppression of iPTH with cinacalcet reverses bone loss in the proximal femur. Cinacalcet alleviated itching.

A computerized treatment algorithm trial to optimize mineral metabolism in ESRD

BACKGROUND AND OBJECTIVES

Achievement of mineral targets in patients receiving dialysis remains challenging. This study sought to evaluate outcomes for phosphorus, calcium, and parathyroid hormone when a dialysis population was switched from a predominantly active vitamin D analogue treatment regimen to a computerized algorithm incorporating both cinacalcet and active vitamin D as potential first-line therapies.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This longitudinal prospective trial enrolled 92 patients undergoing maintenance hemodialysis. Baseline measures (the average of the 3 months before computerized algorithm implementation) were compared with the proportion of patients achieving the prespecified targets at 6 and 12 months.

RESULTS

After 6 months there was a statistically significant improvement in the percentage of patients achieving the primary and secondary phosphorus targets (primary: phosphorus ≤ 5.5 mg/dl, increase from 41% to 75%, P<0.001; secondary: phosphorus 3.0-4.6 mg/dl, increase from 16% to 38%; P=0.005). These improvements were sustained at 12 months. There was a statistically significant improvement in the percentage of patients achieving all three prespecified secondary endpoints (an increase from 12.8% to 25.6% at 12 months; P=0.04); however, this was mainly driven by improved phosphorus control. The proportion of patients achieving the primary or secondary parathyroid hormone targets did not improve.

CONCLUSIONS

A greater proportion of dialysis patients achieved improved phosphorus but not parathyroid hormone control by switching from a predominantly active vitamin D analogue-based treatment regimen for mineral and bone disorder to a computer-driven algorithm that incorporated cinacalcet and low-dose active vitamin D analogues as first-line therapy.

Therapeutic management of post-kidney transplant hyperparathyroidism

Left uncontrolled, persistent post-kidney transplant hyperparathyroidism (HPT) may lead to or exacerbate pre-existing bone and cardiovascular disease. Parathyroidectomy has long been the primary treatment option for long-term uncontrolled HPT in post-kidney transplant patients. However, patients with contraindications for surgery and parathyroidectomy-associated complications, including graft loss, highlight the need for other approaches. Conventional medical therapies have limited impact on serum calcium (Ca) and parathyroid hormone (PTH) levels. Bisphosphonates and calcitonin, used to spare bone loss, and phosphorus supplementation, to correct hypophosphatemia, do not directly regulate PTH or Ca. Although vitamin D supplementation can reduce PTH, it is often contraindicated because of hypercalcemia. Studies of the calcimimetic cinacalcet in patients with post-kidney transplant HPT suggest that it can rapidly reduce serum PTH and Ca concentrations while increasing serum phosphorus concentrations toward the normal range. Although the clearest application for cinacalcet is the non-surgical treatment of hypercalcemic patients with persistent HPT, current indications for other transplant patients are as yet uncertain. Further studies are needed to determine the utility of cinacalcet in patients with spontaneous resolution of HPT or low bone turnover. This review discusses the pathophysiology of post-kidney transplant HPT, associated complications, and current options for clinical management.

Mineral metabolism and vitamin D in chronic kidney disease--more questions than answers

Patients with chronic kidney disease (CKD) are at increased risk of total and cardiovascular morbidity and mortality. The underlying pathophysiology of this association remains largely unexplained and there is currently no clear interventional pathway. Emphasis has been placed on measuring serum levels of calcium, phosphate and parathyroid hormone (PTH) to monitor disease progression, driven by the assumption that achieving values within the 'normal' range will translate into improved outcomes. Retrospective studies have provided a body of evidence that abnormal levels of mineral biomarkers, and phosphate in particular, are associated with clinical events. Disturbances in vitamin D metabolism are also likely to contribute to the pathophysiology of CKD. Designing studies that yield useful information has proved to be difficult, partly owing to conceptual and financial limitations, but also because of the tight interdependency of calcium, phosphate and PTH, and the potential impact of vitamin D on these mineral metabolites. An intervention that perturbs any one of these factors is likely to exert effects on the others, making isolation of the individual variables almost impossible. However, some therapies in current use have the potential to act as probes to answer questions relating to the association between mineral biomarkers and outcomes in CKD.

Secondary hyperparathyroidism: Risk factor for development of cardiovascular complications in patients on hemodialysis

Introduction. Cardiovascular disease is a leading cause of death among hemodialysis patients. Secondary hyperparathyroidism. Secondary hyperparathyroidism is one of the main factors for the development of cardiovascular complications among these patients. A high concentration of parathormone, hypercalcemia, hyperphosphatemia and high calcium x phosphate product among dialysis patients play a crucial role in the development of vascular (calcification of coronary artery) and valvular calcifications. Discussion and conclusion. With every new patient on hemodialysis it is necessary to see if there is a vascular/valvular calcification in order to single out the patients at risk of progression of coronary artery calcification and to use non-calcium containing binder phosphate in due time. Noncalcium containing binder phosphate, new active vitamin D agents and calcimimetics prevent the development of secondary hyperparathyroidism as well as cardiovascular complications and decrease the rate of cardiovascular morbidity and mortality of these patients.

Calcimimetics in the chronic kidney disease-mineral and bone disorder

Mineral and bone disorders (MBD) are both an early and very common complication of chronic kidney disease (CKD). It is now accepted that they represent a significant risk factor, explaining the high cardiovascular morbidity and mortality in CKD patients. During the last decade, we have been witnessing many advances in the nomenclature, classification, pathophysiology, diagnosis, and treatment of CKD and some of its complications, such as CKD-MBD. The identification of the calcium-sensing receptor (CaSR) involvement in the pathogenesis of primary and secondary hyperparathyroidism (SHPT) and the availability of a new class of drugs called calcimimetics are two outstanding examples. Cinacalcet, the only available calcimimetic, has been shown to be a very effective therapeutic tool in CKD-MBD. Many clinical trials with cinacalcet in hemodialysis patients with SHPT have shown a reduction in parathyroid hormone, calcium (Ca), phosphate (P) and Ca x P product levels, allowing far greater success in reaching therapeutic goals as recommended by international guidelines. Additionally, some studies have shown that the use of cinacalcet may improve other aspects of CKD-MBD, reducing the risk of vascular calcification and parathyroidectomy, among others. Prospective studies on dialysis patients, with hard endpoint data, are currently underway. This review summarizes the most significant aspects of calcimimimetics based on both experimental and clinical results, underlining their possibilities not only for the treatment of isolated SHPT but also for other CKD-MBD related conditions.

Impact of cinacalcet hydrochloride on bone histology in patients with secondary hyperparathyroidism

Serum parathyroid hormone (PTH) levels are effectively decreased by cinacalcet hydrochloride (HCl) in patients with secondary hyperparathyroidism. We assessed the impact of cinacalcet HCl on bone histology in these patients. Four hemodialysis patients with secondary hyperparathyroidism (intact PTH > or = 300 pg/mL) were treated with cinacalcet HCl with low-doses of vitamin D sterols as well as calcium-based phosphate binders for 52 weeks. Patients 1, 2, 3 and 4 were aged 55, 65, 61 and 70 years old, and the duration of hemodialysis in the patients was 84, 176, 125 and 216 months, respectively. Serum intact PTH, serum bone metabolism markers and bone histomorphometric parameters were determined before and after 52 weeks of the treatment. Serum intact PTH decreased from 1110, 880, 330 and 980 pg/mL to 233, 80, 88 and 116 pg/mL, respectively, in the four patients after 52 weeks of treatment with cinacalcet HCl. Serum levels of bone metabolism markers and all of the histomorphometric resorption parameters decreased in these patients. In particular, fibrosis volume decreased to 0% in all of the patients. Static formation parameters, including osteoblast surface and osteoid-related parameters, all decreased after the treatment, indicating an increase of mineralized bone volume during the treatment. Dynamic parameters except for activation frequency decreased after the treatment, indicating significant suppression of bone turnover. Cinacalcet HCl with low-doses of vitamin D sterols suppressed serum PTH with no significant changes of serum calcium levels. In addition, long-term administration of cinacalcet HCl improved hyperparathyroid bone diseases in patients with secondary hyperparathyroidism.

A randomized, double-blind, placebo-controlled study to assess the efficacy and safety of cinacalcet HCl in participants with CKD not receiving dialysis

BACKGROUND

Secondary hyperparathyroidism is observed in patients with early chronic kidney disease (CKD). This study investigated the safety and efficacy of cinacalcet for secondary hyperparathyroidism in participants with CKD not receiving dialysis.

STUDY DESIGN

Double-blind, randomized, 32-week, phase 3 study.

SETTING & PARTICIPANTS

404 participants with stage 3 or 4 CKD from 73 centers in 9 countries.

INTERVENTIONS

Cinacalcet:placebo (3:1 ratio).

OUTCOMES & MEASUREMENTS

Proportion of participants with a mean decrease of 30% or greater in intact parathyroid hormone (iPTH) level, proportion with iPTH level of 70 or less or 110 or less pg/mL (stage 3 and 4 CKD, respectively), and mean percentage of iPTH change from baseline, all during the efficacy-assessment phase.

RESULTS

A greater proportion of cinacalcet than placebo participants achieved a 30% or greater decrease in iPTH level (74% versus 28%; P < 0.001), corresponding to a 43.1% decrease in iPTH level from baseline (cinacalcet) compared with a 1.1% increase (placebo). At week 32, serum calcium levels were 8.9 +/- 0.8 mg/dL (-8.9%; cinacalcet) and 9.9 +/- 0.6 mg/dL (+0.8%; placebo), phosphorus levels were 4.5 +/- 1.0 mg/dL (+21.4%) and 4.0 +/- 0.7 mg/dL (+6.8%), and calcium-phosphorus product values were 40.1 +/- 8.3 mg(2)/dL(2) (+18.9%) and 38.9 +/- 6.9 mg(2)/dL(2) (+17.1%), respectively. During the study course, 62% (cinacalcet) and 1% (placebo) of participants experienced 2 consecutive serum calcium concentrations less than 8.4 mg/dL. They generally were asymptomatic and without significant clinical consequences. Treatment generally was well tolerated, and most adverse events were mild to moderate in severity.

LIMITATIONS

The study was not designed to assess the effects of cinacalcet on vascular calcification, bone histomorphometric parameters, or other clinical outcomes. It is not known whether the observed differences in changes in iPTH levels are clinically more important than observed differences in changes in serum calcium or phosphorus levels or dosages of vitamin D sterols and phosphate binders.

CONCLUSIONS

These data show that cinacalcet treatment in patients with CKD not receiving dialysis can decrease plasma iPTH levels, but with frequent (albeit generally asymptomatic) serum calcium levels less than 8.4 mg/dL and increases in serum phosphorus levels.

Treatment of secondary hyperparathyroidism in CKD patients with cinacalcet and/or vitamin D derivatives

The discovery of the calcium-sensing receptor (CaR) 15 yr ago was rapidly followed by the development of drugs modulating its activity, the so-called calcimimetics (increasing the CaR signal) and calcilytics (decreasing the CaR signal). The indication for calcimimetics is treatment of primary and secondary hyperparathyroidism, whereas calcilytics have potential for treatment of osteoporosis. A large number of clinical studies has shown that cinacalcet, the only presently available calcimimetic, effectively reduces serum parathyroid hormone in dialysis patients with secondary hyperparathyroidism. In contrast to the effect of active vitamin D derivatives, it simultaneously decreases serum calcium and phosphorus. Experimental studies showed a concomitant decrease in parathyroid hyperplasia. In the treatment of secondary hyperparathyroidism of dialysis patients, important questions remain unresolved, for example, whether there are reasons to prefer calcimimetics to active vitamin D derivatives and whether combined administration offers advantages compared with calcimimetics or active vitamin D given in isolation. For lowering parathyroid hormone, available evidence from recent studies suggests that combination therapy should be preferred to single drug treatment because of less side-effects and greater efficacy in controlling parathyroid overfunction. Future randomized controlled trial must answer whether calcimimetics impact on cardiovascular events or survival and whether in this respect there are differences between vitamin D sterols and calcimimetics.

Treatment of secondary hyperparathyroidism in kidney disease: what we know and do not know about use of calcimimetics and vitamin D analogs

There is a growing understanding of the pathophysiology of secondary hyperparathyroidism (SHPT) and a recent emergence of new agents for SHPT treatment in patients with advanced kidney disease. At the same time, appreciation that mineral metabolic derangements promote vascular calcification and contribute to excess mortality, along with recognition of potentially important “non-classical” actions of vitamin D, have prompted the nephrology community to reexamine the use of various SHPT treatments, such as activated vitamin D sterols, phosphate binders, and calcimimetics. In this review, the evidence for treatment of SHPT with calcimimetics and vitamin D analogs is evaluated, with particular consideration given to recent clinical trials that have reported encouraging findings with cinacalcet use. Additionally, several controversies in the pathogenesis and treatment of SHPT are explored. The proposition that calcitriol deficiency is a true pathological state is challenged, the relative importance of the vitamin D receptor and the calcium sensing receptor in parathyroid gland function is summarized, and the potential relevance of non-classical actions of vitamin D for patients with advanced renal disease is examined. Taken collectively, the balance of evidence now supports a treatment paradigm in which calcimimetics are the most appropriate primary treatment for SHPT in the majority of end stage renal disease patients, but which nevertheless acknowledges an important role for modest doses of activated vitamin D sterols.

Calcimimetics or vitamin D analogs for suppressing parathyroid hormone in end-stage renal disease: time for a paradigm shift?

Considerable advances have been made in the understanding of the pathogenesis and treatment of secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD). These include the discovery that the calcium-sensing receptor has an important role in the regulation of parathyroid gland function, the development of calcimimetics to target this receptor, the recognition that vitamin D receptor activation has important functions beyond the regulation of mineral metabolism, the identification of the phosphaturic factor fibroblast growth factor 23 and the contribution of this hormone to disordered phosphate and vitamin D metabolism in CKD. However, despite the availability of calcimimetics, phosphate binders, and vitamin D analogs, control of SHPT remains suboptimal in many patients with advanced kidney disease. In this Review, we explore several unresolved issues regarding the pathogenesis and treatment of SHPT. Specifically, we examine the significance of elevated circulating fibroblast growth factor 23 levels in CKD, question the proposition that calcitriol deficiency is truly a pathological state, explore the relative importance of the vitamin D receptor and the calcium-sensing receptor in parathyroid gland function and evaluate the evidence to support the treatment of SHPT with calcimimetics and vitamin D analogs. Finally, we propose a novel treatment framework in which calcimimetics are the primary therapy for suppressing parathyroid hormone production in patients with end-stage renal disease.

Cinacalcet is efficacious in pediatric dialysis patients

Secondary hyperparathyroidism (high-turnover bone disease, or HTBD) is manifested by elevated parathyroid hormone (PTH) levels. Control of HTBD may be achieved by maintaining low serum phosphorous levels and administering vitamin D therapy, although some patients continue to exhibit high PTH levels. We report the results of the efficacy of the calcimimetic cinacalcet in six hemodialysis (HD) and three peritoneal dialysis (PD) pediatric patients with HTBD, age 14.5 +/- 1.0 (range 7.5-17.5) years. Six patients received 30 mg/day, one required 60 mg/day, and two received 120 mg/day. Treatment with cinacalcet resulted in a 61% decline in intact PTH (iPTH) levels (1,070 +/- 171.5 pretreatment to 417.6 +/- 97.8 posttreatment pg/ml, p = 0.005). Serum alkaline phosphatase also declined (561.8 +/- 169.6 U/L pretreatment to 390.3 +/- 110.3 U/L posttreatment pg/ml). During therapy, serum calcium (p = 0.9) and phosphorous (p = 0.9) levels, calcium-phosphorous product (p = 0.8), systolic blood pressure (BP) (p = 1.0), diastolic BP (p = 0.8), and hemoglobin (p = 0.9) remained unchanged. The dose of oral calcitriol for the three patients on PD while receiving cinacalcet trended downward (0.8 +/- 0.2 pretreatment vs. 0.5 +/- 0.0 microg/day posttreatment pg/ml), as did the dose of paracalcitol for those receiving HD (6.6 +/- 2.3 pretreatment vs. 4.3 +/- 1.7 micrograms/day posttreatment pg/ml). We conclude that short-term treatment with the calcimimetic cinacalcet is efficacious in adolescent dialysis patients.

Cinacalcet for secondary hyperparathyroidism in children with end-stage renal disease

The efficacy and acceptability of cinacalcet for treatment of secondary hyperparathyroidism (SHPT) was assessed in seven pediatric patients suffering from end-stage renal disease (ESRD) presenting with inadequately controlled SHPT despite conventional management. Patients received daily treatment with cinacalcet (dosage 0.25 mg/kg body weight) for a total of 4 weeks. Within 4 h after application of the first dose, median levels of serum parathyroid hormone (PTH) had decreased from 932 pg/ml (range 511-1,938 pg/ml) to 584 pg/ml (88-937 pg/ml), and final pre-dose values after 4 weeks were 199 pg/ml (121-940 pg/ml; each P < 0.05 versus baseline). Median concentrations of serum calcium (Ca) decreased within 4 h of the first administration, from 2.56 mmol/l to 2.38 mmol/l, returning to 2.58 mmol/l at 24 h, and they remained slightly decreased compared to baseline values thereafter (each P < 0.05 versus baseline). Both the median levels of serum phosphorus (P) and the Ca x P ion product decreased significantly during the 4-week period. Cinacalcet was well tolerated and without drug-related adverse effects. Thus, even with approximately half of the dose usually given to adult dialysis patients, PTH and the Ca x P ion product were markedly reduced in pediatric ESRD patients presenting with inadequately controlled SHPT. Therefore, our results support the initiation of a randomized, controlled, long-term trial in children.

Long-term cinacalcet HCl treatment improved bone metabolism in Japanese hemodialysis patients with secondary hyperparathyroidism

BACKGROUND/AIMS

Few clinical trials conducted with cinacalcet have thoroughly addressed its effects of on bone metabolism. We assessed the effects of cinacalcet on bone markers in Japanese hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT).

METHODS

200 Japanese HD patients with intact PTH (iPTH) levels > or = 300 pg/ml were enrolled. The dose of cinacalcet was titrated from 25 up to 100 mg/day to achieve iPTH levels < or = 250 pg/ml for 52 weeks.

RESULTS

At the end of the study visit, 57.8% of patients (115/199) had achieved iPTH levels < or = 250 pg/ml. Serum Ca, phosphorus (P) and Ca x P levels decreased rapidly and were maintained throughout the study. At week 52, all bone metabolic markers levels had decreased significantly from baseline. Although bone resorption markers gradually decreased throughout the study period, bone alkaline phosphatase significantly increased during the first 4 weeks and then gradually decreased.

CONCLUSIONS

The time courses of changes in bone markers after cinacalcet treatment resembled those observed after surgical parathyroidectomy (PTx), sometimes described as the hungry bone syndrome, indicating that cinacalcet treatment induces a rapid recovery in bone response to calcium. In addition, long-term efficacy and safety of cinacalcet were also observed in Japanese patients undertaking long-term hemodialysis (167.0 +/- 81.4 months).

New strategies for the treatment of hyperparathyroidism incorporating calcimimetics

BACKGROUND

Hyperparathyroidism (HPT), characterised by increased parathyroid hormone (PTH) secretion and parathyroid hyperplasia, can be caused by physiologic defects in the parathyroid gland (primary HPT [PHPT]) or as a consequence of declining renal function (secondary HPT [SHPT]).

OBJECTIVE

To review the safety and efficacy of cinacalcet in the treatment of SHPT and PHPT.

METHODS

Studies indexed in NLM/PubMed investigating the safety, efficacy, and pharmacokinetics of cinacalcet for PHPT and SHPT and supporting preclinical evidence.

RESULTS/CONCLUSION

Recent evidence has demonstrated the efficacy of the calcimimetic cinacalcet in the treatment of PHPT and SHPT. Compared with traditional therapies such as vitamin D sterols and phosphate binders, cinacalcet treatment can allow an increased proportion of patients with SHPT to improve Kidney Disease Outcomes Quality Initiative (KDOQI) Bone Metabolism and Disease laboratory parameter target attainment. Recent evidence suggests that improvements in these biochemical parameters with cinacalcet can translate into improved morbidity and mortality. Cinacalcet lowers PTH and calcium in patients following renal transplantation, and also normalises serum calcium in patients with PHPT. Ongoing studies are focusing and future studies are likely to focus on the effect of cinacalcet on clinical outcomes and on novel strategies for the integration of cinacalcet with traditional therapies to improve serum PTH and mineral metabolism control.

Combined therapy with cinacalcet and low doses of vitamin D sterols in patients with moderate to severe secondary hyperparathyroidism

BACKGROUND

Adequate control of all four KDOQI biochemical targets for chronic kidney disease, bone and mineral disorder (CKD-MBD), which include parathyroid hormone (PTH), calcium (Ca), phosphorus (P) and Ca x P, remains difficult and is accomplished in <6% of patients receiving haemodialysis. The objective of the current study was to determine whether treatment with cinacalcet combined with low doses of vitamin D sterols improves control of both PTH and Ca x P among haemodialysis patients with secondary hyperparathyroidism (sHPT).

METHODS

This multicentre, open-label study enrolled haemodialysis subjects (N = 444) with moderate to severe sHPT (mean serum biPTH > 160-430 pg/mL) (approximately iPTH 300-800 pg/mL or ng/L). Cinacalcet was titrated sequentially (30-180 mg/day) during an 8-week dose-titration phase to achieve biPTH <or=160 pg/mL (approximately iPTH 300 pg/mL or ng/L) and efficacy was assessed over 8 weeks. At week 2 of the study, subjects receiving vitamin D sterols had doses reduced to the equivalent of 2 mcg of paricalcitol three times a week or 6 mcg/week. Among the efficacy endpoints were the proportion of subjects with mean biPTH <or=160 pg/mL (approximately iPTH 300 pg/mL or ng/L), with mean Ca x P <or=55 mg(2)/dL(2) (4.4 mmol(2)/L(2)) and with both simultaneously during the assessment phase.

RESULTS

The majority of subjects (n = 375) reached the assessment phase of the study and were included in efficacy analyses; 39 subjects withdrew due to adverse events. Sixty-two percent of subjects achieved the biPTH target, 83% achieved the Ca x P target and 54% reached both targets. Treatment reduced biPTH by 35% (P < 0.0001), calcium by 11% (P < 0.0001), phosphorus by 7% (P < 0.0001) and Ca x P by 17% (P < 0.0001). The proportion of subjects with values for biPTH, for Ca x P and for both biPTH and Ca x P within the target range during the assessment phase did not differ between subjects who received cinacalcet together with vitamin D sterols, and those who received cinacalcet alone.

CONCLUSION

Among subjects with moderate to severe sHPT undergoing haemodialysis, combined therapy with cinacalcet and low doses of vitamin D sterols improved achievement of the biochemical targets for CKD-MBD recommended by the KDOQI guidelines.

Calcimimetics as an adjuvant treatment for familial hypophosphatemic rickets

BACKGROUND AND OBJECTIVES

The treatment for X-linked hypophosphatemia (XLH) with phosphate and calcitriol can be complicated by secondary hyperparathyroidism and nephrocalcinosis. Furthermore, vitamin D and phosphate stimulate FGF23 production, the pathogenic factor causing XLH. We investigated in XLH patients: 1) whether treatment with the calcimimetic agent, cinacalcet, will block the rise in parathyroid hormone (PTH) caused by phosphate administration; and 2) whether treatment with oral phosphate and calcitriol increases FGF23 levels.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Eight subjects with XLH were given a single oral dose of phosphate, followed the next day by combined treatment with phosphate and cinacalcet. Serum measurements of ionized calcium (Ca), phosphate, creatinine, intact PTH, 1,25(OH)(2)D, FGF23, and tubular threshold for phosphate/glomerular filtration rate (TP/GFR) were assessed in response to short-term treatment with phosphate and cinacalcet and compared with long-term administration of phosphate and calcitriol.

RESULTS

Oral phosphate load increased serum phosphate, decreased ionized calcium, and increased PTH. Twenty-four hours later, FGF23 significantly increased and 1,25(OH)(2)D decreased. The concomitant administration of phosphate and cinacalcet resulted in further decrease in serum Ca(2+) but suppression of PTH and greater increase in serum phosphate and TP/GFR. Chronic treatment with phosphate and calcitriol resulted in a smaller increment in serum phosphate and high serum FGF23.

CONCLUSIONS

Traditional therapy of XLH with phosphate and calcitriol elevates FGF23 and has the potential to stimulate PTH. Short-term treatment with cinacalcet suppresses PTH, leading to increase in TP/GFR and serum phosphate. Thus, long-term clinical studies are needed to investigate whether cinacalcet may be a useful adjuvant in the treatment of XLH, allowing the use of lower doses of phosphate and calcitriol.

Long-term outcomes of cinacalcet and paricalcitol titration protocol for treatment of secondary hyperparathyroidism

Long-term outcomes of combined cinacalcet and paricalcitol therapy for secondary hyperparathyroidism (SHPT) in patients failing traditional therapies with phosphate binders and active vitamin D compound analogs are not well described. We implemented a titration protocol for cinacalcet and paricalcitol and assessed its long-term effects on bone metabolism and disease in hemodialysis (HD) patients. Thirty-five patients were started on 30 mg of cinacalcet daily. After 12 months, median cinacalcet dose was 60 mg. There was a 33% increase in number of patients receiving paricalcitol. Average corrected serum calcium (Ca) decreased from 9.5 to 8.8 mg/dl (p = 0.003, 95% CI 0.34-1.04); phosphorus (P) from 6.2 to 5.5 mg/dl (p = 0.047, 95% CI 0.01-1.34); Ca x P product from 58 to 48 (p = 0.001, 95% CI 4.2-15.7); and intact PTH (iPTH) from 426 +/- 274 to 300 +/- 228 pg/ml (p = 0.03, 95% CI 19.3-401.7). Number of patients achieving three or more K/DOQI criteria increased by 29% (p = 0.009).

Medical therapy of secondary hyperparathyroidism in chronic kidney disease: old and new drugs

Secondary hyperparathyroidism (SHPT), a common complication of chronic kidney disease, is characterised by elevated serum levels of parathyroid hormone, parathyroid hyperplasia, excessive bone resorption and increased risk for cardiovascular morbidity. The stringent metabolic targets proposed by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) for patients with SHPT are difficult to achieve using conventional treatment regimens. Several new agents, including new vitamin D sterols and phosphate binders, as well as a novel class of compounds--the calcimimetics--have been developed in recent years. This review examines new and traditional therapies for SHPT and how these can best be utilised in order to achieve the new K/DOQI targets.