Efficacy and safety of cinacalcet for the treatment of secondary hyperparathyroidism in patients with advanced chronic kidney disease before initiation of regular dialysis

Efficacy and safety of microwave ablation treatment for secondary hyperparathyroidism: systematic review and meta-analysis

Purpose: The present systematic review and meta-analysis was designed to evaluate the efficacy and safety of microwave ablation (MWA) treatment for secondary hyperparathyroidism (SHPT).Materials and methods: The study authors systematically searched the Web of Science, Cochrane Library, PubMed, Embase and Ovid databases for studies published in English prior to 7October 2019. All studies included in the meta-analysis measured levels of parathyroid hormone (PTH), calcium and phosphorus, and included data related to complications following MWA treatment for SHPT.Results: The meta-analysis ultimately included 233 patients from two retrospective cohort studies and six retrospective self-control studies. Compared to PTH level measurements obtained after MWA, measurements obtained at one day (weighted mean differences (WMD): 890.314, 95% confidence interval (CI): 767.121-1013.506, p < 0.01) , one week (WMD: 860.298, 95% CI: 759.401-961.194, p < 0.01), one month (WMD: 800.846, 95% CI: 687.709-913.983, p < 0.01) and six months (WMD: 860.847, 95% CI: 745.214-976.480, p < 0.01) after MWA were significantly lower. Calcium and phosphorus levels at one day and one week after MWA were also significantly lower than those measured before MWA. After MWA, the incidence of nerve injury was 1.2% (3/233; effect size (ES): 0.022, 95% CI: -0.003-0.048, p < 0.01). After MWA, the incidence of hypocalcemia was 15.8% (37/233; ES: 0.449, 95% CI: 0.341-0.556, p < 0.01).Conclusion: The preliminary results of this meta-analysis indicate that MWA may be effective and safe in treating patients with SHPT, and that future prospective research and randomized controlled trials (RCT) are necessary.

Evaluating extended-release calcifediol as a treatment option for chronic kidney disease-mineral and bone disorder (CKD-MBD)

Introduction: Extended-release calcifediol (ERC) is an orally administered prohormone of active vitamin D (1,25-dihydroxyvitamin D [1,25D]) designed to safely and sufficiently increase serum total 25-hydroxyvitamin D (25D) to reduce elevated parathyroid hormone (PTH) in patients with non-dialysis-chronic kidney disease (ND-CKD). ERC is currently approved in the United States and Canada.Areas covered: Herein, key clinical data relating to the pharmacokinetics, pharmacodynamics, efficacy and safety of ERC are reviewed.Expert opinion: Currently available treatment options for secondary hyperparathyroidism (SHPT) in ND-CKD have limitations: the effectiveness of nutritional vitamin D supplements for reduction of PTH levels is unproven and active (1α-hydroxylated) vitamin D analogues elevate serum calcium, which increases the risk of hypercalcemia and vascular calcification. Clinical studies show that ERC is an effective, well tolerated treatment for SHPT in ND-CKD. ERC gradually raises serum 25D levels, resulting in physiologically regulated increases in serum 1,25D and sustained reductions in PTH, while avoiding clinically meaningful increases in serum phosphorus, calcium and fibroblast growth factor 23. ERC offers a new, effective and well tolerated treatment option for the early management of SHPT in patients with ND-CKD.

Long-term effectiveness of cinacalcet in non-dialysis patients with chronic kidney disease and secondary hyperparathyroidism

Background

Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD). Cinacalcet use is controversial in non-dialysis patients.

Methods

This retrospective observational study recruited patients receiving cinacalcet (off-label use) in 2010 and 2011. Patients were followed for three years from the beginning of treatment using an intention-to-treat approach.

Results

Forty-one patients were studied: 14 CKD stage 3 (34.1%), 21 CKD stage 4 (51.2%), and 6 CKD stage 5 (14.6%). Median baseline parathyroid hormone (PTH) was 396 (101–1,300) pg/mL. Upon cinacalcet treatment (22 ± 12 months), PTH levels decreased by ≥ 30% in 73.2% of patients (P < 0.001; 95% confidence interval [CI], 59–87%), with a mean time for response of 18.7 months (95% CI, 15.4–22.1). Sixteen patients were followed for 36 months and treated for 32 ± 9 months. Mean reduction in their PTH levels was 50.1% (P < 0.001; 95% CI, 33.8–66.4%) at 36 months, with 62.5% of patients (P < 0.001; 95% CI, 35.9–89.1%) presenting reductions of ≥ 30%. Serum calcium levels decreased from 9.95 ± 0.62 mg/dL to 9.21 ± 0.83 and 9.12 ± 0.78 mg/dL at 12 and 36 months, respectively (P < 0.001). Serum phosphorus levels increased from 3.59 ± 0.43 to 3.82 ± 0.84 at 12 months (P = 0.180), remaining so at 36 months (P = 0.324). At 12 and 36 months, 2 (12.5%) patients experienced hypocalcemia. Meanwhile, 1 (6.3%) and 4 (25.0%) patients reported hyperphosphatemia at 12 and 36 months, respectively.

Conclusion

Cinacalcet remained effective for at least 36 months in non-dialysis patients with SHPT. Electrolytic disturbances were managed with concurrent use of vitamin D and its analogs or phosphate binders.

Parathyroidectomy in the Management of Secondary Hyperparathyroidism

Secondary hyperparathyroidism develops in CKD due to a combination of vitamin D deficiency, hypocalcemia, and hyperphosphatemia, and it exists in nearly all patients at the time of dialysis initiation. There is insufficient data on whether to prefer vitamin D analogs compared with calcimimetics, but the available evidence suggests advantages with combination therapy. Calcium derangements, patient adherence, side effects, and cost limit the use of these agents. When parathyroid hormone level persists >800 pg/ml for >6 months, despite exhaustive medical interventions, monoclonal proliferation with nodular hyperplasia is likely present along with decreased expression of vitamin D and calcium-sensing receptors. Hence, surgical parathyroidectomy should be considered, especially if concomitant disorders exist, such as persistent hypercalcemia or hyperphosphatemia, tissue or vascular calcification including calciphylaxis, and/or worsening osteodystrophy. Parathyroidectomy is associated with 15%-57% greater survival in patients on dialysis, and it also improves hypercalcemia, hyperphosphatemia, tissue calcification, bone mineral density, and health-related quality of life. The parathyroidectomy rate in the United States declined to approximately seven per 1000 dialysis patient-years between 2002 and 2011 despite an increase in average parathyroid hormone levels, reflecting calcimimetics introduction and uncertainty regarding optimal parathyroid hormone targets. Hospitalization rates are 39% higher in the first postoperative year. Hungry bone syndrome occurs in approximately 25% of patients on dialysis, and profound hypocalcemia requires high doses of oral and intravenous calcium along with calcitriol supplementation. Total parathyroidectomy with autotransplantation carries a higher risk of permanent hypocalcemia, whereas risk of hyperparathyroidism recurrence is higher with subtotal parathyroidectomy. Given favorable long-term outcomes from observational parathyroidectomy cohorts, despite surgical risk and postoperative challenges, it is reasonable to consider parathyroidectomy in more patients with medically refractory secondary hyperparathyroidism.

Prospective cohort study: Cinacalcet-mediated lowering of PTH level and cardiovascular disease mortality in younger Korean patients with stage 5 CKD at a Korean secondary hospital

WHAT IS KNOWN AND OBJECTIVES

Cinacalcet may reduce cardiovascular disease (CVD) mortality in elderly patients with chronic kidney disease (CKD). However, previous studies of the clinical responses to cinacalcet have exhibited discrepancies due to highly variable baseline levels of parathyroid hormone (PTH), kidney function and age. Little is known about the true effect of cinacalcet on stage 5 CKD. The objective of the current observational study was to evaluate whether cinacalcet-mediated lowering of PTH levels improves all-cause mortality and cardiovascular disease mortality in younger stage 5 CKD patients (mean age <55 years).

METHODS

This prospective, cohort study reviewed the electronic medical records (EMRs) of CKD patients (n=540) with secondary hyperparathyroidism (SHPT) for a period of 36 months. Of 540 patients, 104 subjects met the inclusion criteria and were included in the final evaluation (mean serum iPTH 688.7 pg/mL). Patients were divided into a cinacalcet group (n=43) and a non-cinacalcet group (n=61).

RESULTS AND DISCUSSION

Comparing the cinacalcet group to the non-cinacalcet group, Cox proportional hazard modelling found that all-cause mortality was five (31.3%) in the cinacalcet group and three (15.8%) in the non-cinacalcet group for patients with serum levels of PTH>600 pg/mL [P=.277, hazard ratio 2.213, 95% confidence interval (CI): 0.529-9.262]. Cardiovascular disease mortality (CVD: heart disease) occurred in two (5.3%) in the cinacalcet group and one (2.1%) in the non-cinacalcet group [P=.425, HR 2.611, 95% CI: 0.228-9.939]. Overall, there were no significant differences in CVD mortality between the two groups.

WHAT IS NEW AND CONCLUSION

Cinacalcet was not associated with decreases in all-cause mortality or CVD mortality in younger stage 5 CKD patients with high PTH levels (>600 pg/mL). This could be explained by the diversity of the population in terms of the patient's age, health insurance policies, target serum level of biochemical and PTH, and glomerular filtration rate (GFR) at admission. These data, although based on an observational study, indicate that adding cinacalcet to the current standard care for younger stage 5 CKD patients should be re-evaluated.

Recurrent primary hyperparathyroidism due to Type 1 parathyromatosis

Parathyromatosis is a rare condition consisting of multiple nodules of benign hyperfunctioning parathyroid tissue scattered throughout the neck and superior mediastinum. As a potential cause of recurrent or persistent hyperparathyroidism, parathyromatosis is a challenging condition to diagnose and treat. The optimal evaluation and management of patients with parathyromatosis is not well established. The reported case involves a patient who was initially diagnosed with primary hyperparathyroidism. The diagnosis of Type 1 parathyromatosis was made after the patient developed recurrent hyperparathyroidism with hypercalcemia and osteoporosis 17 years after the initial operation and underwent two additional operations. The majority of parathyromatosis cases are diagnosed in the setting of secondary hyperparathyroidism. Consensus regarding the preoperative diagnosis and evaluation is lacking due to the paucity of cases of this rare clinical entity. Management involves complete surgical extirpation of all identifiable rests of parathyroid tissue. Intra-operative parathyroid hormone level monitoring and frozen section examination are excellent tools that could increase the rates of initial operative success. Despite this, long-term disease remission is rare, and medical therapy, including calcimimetics and bisphosphonates, may be required for postoperative or non-operative management.

Effectiveness of Cinacalcet in Patients with Chronic Kidney Disease and Secondary Hyperparathyroidism Not Receiving Dialysis

Background

Secondary hyperparathyroidism (SHPT) is a common complication in chronic kidney disease (CKD) patients. Cinacalcet could be a therapeutic option although its use is controversial in patients not receiving dialysis. Thus, the aim of this study is to assess the effectiveness and safety of cinacalcet in patients with CKD and SHPT without renal replacement treatment (RRT) and without renal transplantation (RT).

Methods

A retrospective observational study was conducted. Patients were included if they had collected cinacalcet, under off-label use, during 2010 and 2011. Patients selected were followed from the beginning of cinacalcet therapy for one year of treatment.

Results

A total of 37 patients were included with CKD stage 3 (38%), 4 (51%) and 5 (11%). Baseline mean PTH value was 400.86 ± 168.60 mg/dl. At 12 months, a 67% of patients achieved at least a 30% reduction in their PTH value (p<0.001; CI 49.7–83.6), and the overall mean reduction of PTH values was 38% (p< 0.001; IC -49.1, -27.5). A 28% of the patients achieved KDOQI PTH goals (p = 0.003, CI 12%-50%). At 12 months, mean serum calcium values decreased by 6% and mean serum phosphorus values increased by 13%. A 19% of patients experienced hypocalcemia episodes while an increase of 24% in hyperphosphatemia episodes was observed. A 25% of patients finished cinacalcet before a year of treatment. Main withdrawal reasons were: gastrointestinal and other discomfort (8%), hypocalcaemia (8%), non-compliance (3%), interactions (3%) and excess of efficacy (3%).

Conclusions

Cinacalcet was effective in patients with CKD and SHPT not receiving dialysis. Electrolytic imbalances could be managed with administration of vitamin D and analogues or phosphate binders.

Pharmacogenetic analysis of cinacalcet response in secondary hyperparathyroidism patients

Background

Secondary hyperparathyroidism (SHPT) is one of the major risk factors of morbidity and mortality in end-stage renal disease. Cinacalcet effectively controls SHPT without causing hypercalcemia and hyperphosphatemia. However, there is significant inter-individual response variance to cinacalcet treatment. Therefore, we aimed to evaluate the genetic effects related with parathyroid hormone regulation as factors for cinacalcet response variance.

Methods

Patients with a diagnosis of SHPT based on intact parathyroid hormone (iPTH) >300 pg/mL on dialysis were included in this study. They were over 18 years and have been treated by cinacalcet for more than 3 months. Responders and nonresponders were grouped by the serum iPTH changes. Twenty-four single nucleotide polymorphisms of CASR, VDR, FGFR1, KL, ALPL, RGS14, NR4A2, and PTHLH genes were selected for the pharmacogenetic analysis.

Results

After adjusting for age, sex, and calcium level, CASR rs1042636 (odds ratio [OR]: 0.066, P=0.027) and rs1802757 (OR: 10.532, P=0.042) were associated with cinacalcet response. The association of haplotypes of CASR rs1042636, rs10190, and rs1802757; GCC (OR: 0.355, P=0.015); and ATT (OR: 2.769, P=0.014) with cinacalcet response was also significant.

Conclusion

We obtained supporting information of the associations between cinacalcet response and CASR polymorphisms. CASR single nucleotide polymorphisms (SNPs) rs1802757, rs1042636, and haplotypes of rs1042636, rs10190, and rs1802757 were significantly associated with cinacalcet response variance.

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.

Antialbuminuric actions of calcilytics in the remnant kidney

Hyperphosphatemia accelerates the progression of chronic kidney diseases. In the present study, the effects of ronacaleret, a calcilytic agent, on renal injury were assessed in the following four groups of rats: 5/6-nephrectomized Wistar rats as a control (C group), rats treated with ronacaleret (3 mg·kg(-1)·day(-1); R group), rats treated with calcitriol (30 ng·kg(-1)·day(-1); V group), and rats treated with both ronacaleret and calcitriol (R + V group). Three months later, rats were euthanized under anesthesia, and the remnant kidneys were harvested for analysis. Albuminuria was lower in the R and V groups than in the C group (P < 0.05). Creatinine clearance was elevated in the R and V groups compared with the C group (P < 0.05). Serum Ca(2+) and renal ANG II were higher in the R + V group than in the C group (P < 0.05 for each), and serum phosphate was reduced in the R group compared with the C group (P < 0.05). Fibroblast growth factor-23 was lower in the R group and higher in the V and R + V groups than in the C group. However, parathyroid hormone did not differ significantly among the four groups. Renal klotho expression was elevated in the R and V groups compared with the C group (P < 0.05). The present data indicate that ronacaleret preserves klotho expression and renal function with reductions in serum phosphate and albuminuria in 5/6-nephrectomized rats. Our findings demonstrate that vitamin D prevents declines in klotho expression and renal function, suppressing albuminuria.

Cinacalcet attenuates hypercalcemia observed in mice bearing either Rice H-500 Leydig cell or C26-DCT colon tumors

Excessive secretion of parathyroid hormone-related protein (PTHrP) by tumors stimulates bone resorption and increases renal tubular reabsorption of calcium, resulting in hypercalcemia of malignancy. We investigated the ability of cinacalcet, an allosteric modulator of the calcium-sensing receptor, to attenuate hypercalcemia by assessing its effects on blood ionized calcium, serum PTHrP, and calcium-sensing receptor mRNA in mice bearing either Rice H-500 Leydig cell or C26-DCT colon tumors. Cinacalcet effectively decreased hypercalcemia in a dose- and enantiomer-dependent manner; furthermore, cinacalcet normalized phosphorus levels, but did not affect serum PTHrP. Ribonuclease protection assay results demonstrated presence of PTHrP receptor, but not calcium-sensing receptor mRNA in C26-DCT tumors. The mechanism by which cinacalcet lowered serum calcium was investigated in parathyroidectomized rats (i.e., without PTH) made hypercalcemic by PTHrP. Cinacalcet attenuated PTHrP-mediated elevations in blood ionized calcium, which were accompanied by increased plasma calcitonin. Taken together these results suggest that the cinacalcet-mediated decrease in serum calcium is not the result of a direct effect on tumor cells, but rather is the result of increased calcitonin release. In summary, cinacalcet effectively reduced tumor-mediated hypercalcemia and corrected hypophosphatemia in mice. Further investigation of cinacalcet for treatment of hypercalcemia of malignancy is warranted.