Emerging drugs for secondary hyperparathyroidism

COMMD5 is involved in the mechanisms of hypotension after parathyroidectomy in patients receiving hemodialysis

BACKGROUND

Secondary hyperparathyroidism (SHPT) is a common complication of end-stage renal disease. Parathyroidectomy (PTx) is often employed for treatment of severe SHPT. However, PTx may cause hypotension via unknown mechanisms. COMM domain-containing protein 5 (COMMD5) in the parathyroid glands has been linked to blood pressure regulation of spontaneously hypertensive rats.

OBJECTIVE

To explore the relationship between COMMD5 levels and reduced BP after PTx in patients receiving hemodialysis (HD).

METHODS AND RESULTS

(1) The study cohort included 31 patients receiving HD who underwent PTx. Serum COMMD5 levels were higher post-PTx vs. pre-PTx. (2) Sprague-Dawley rats (n = 22) were assigned to a 5/6 nephrectomy group or sham surgery group, vascular rings of the thoracic aorta from rats with CKD were incubated with COMMD5, and changes in vascular tension were compared. COMMD5 inhibited vasoconstriction of vascular rings with intact endothelium, but had no effect on vascular rings without the endothelium. (3) Human umbilical vein endothelial cells were stimulated with COMMD5 or small interfering RNA (siRNA). The expression levels of atrial natriuretic peptide (ANP) and endothelial nitric oxide synthase (eNOS) were up-regulated and down-regulated, respectively.

CONCLUSIONS

Serum COMMD5 levels were increased after PTx in SHPT patients. COMMD5 promoted high expression of ANP and eNOS in endothelial cells, leading to vasodilation and resulting in hypotension.

Uremic Leontiasis Ossea: Theoretical Concepts and Practical Considerations

Leontiasis ossea (LO) in chronic kidney disease patients, also known as Sagliker syndrome, is an exceptionally uncommon uremic complication of long-lasting and severe secondary hyperparathyroidism. The prominent features of uremic LO (ULO) encompass the characteristic clinical trial of massive thickening of maxillary and mandibular bones, widening of interdental spaces, and flattening of nasal bridges and nares. Moreover, during the transformation of craniofacial architecture, significant structural and functional consequences may appear, including upper airway patency, visual and hearing acuity, oral phase of swallowing as well as various neurological and psychiatric disorders. Only few cases of ULO have been reported in the literature until now, making challenging not only the traditional diagnostic procedures but also the optimal therapeutic approach. In this narrative review, we aim to explore the underlying pathophysiological mechanisms, summarize the evidence for adverse outcomes, and highlight the current therapeutic strategies for ULO prevention and treatment, given that precise genetic determinants remain elusive.

Evocalcet with vitamin D receptor activator treatment for secondary hyperparathyroidism

This ad hoc analysis of a previously conducted phase 3 head-to-head comparison study of evocalcet and cinacalcet in secondary hyperparathyroidism patients undergoing maintenance hemodialysis evaluated the efficacy and safety of combined once-daily oral evocalcet and intravenous vitamin D receptor activator treatment stratified by weekly vitamin D receptor activator dose (117, 45, and 91 patients in no, low [< 1.5 μg], and high [≥ 1.5 μg] dose groups, respectively). Effects of vitamin D receptor activator were assessed on the basis of intact parathyroid hormone, corrected calcium, phosphorus, and fibroblast growth factor-23 levels; percent changes from baseline; proportions of patients who achieved target intact parathyroid hormone, corrected calcium, and phosphorus at Weeks 28–30; and adverse drug reactions. Intact parathyroid hormone, corrected calcium, phosphorus, and fibroblast growth factor-23 levels decreased in all groups; phosphorus and fibroblast growth factor-23 levels remained high in the high dose group. In the low and high dose groups, greater proportions of patients achieved the corrected calcium target compared with the no dose group (p = 0.043). Ratios of intact-to-C-terminal fibroblast growth factor-23 decreased in all groups. In low and high dose groups, hypocalcemia was less common than in the no dose group (p = 0.014). Evocalcet with concomitant vitamin D receptor activator demonstrated benefits such that more patients achieved the corrected calcium target and exhibited decreased fibroblast growth factor-23 synthesis; the incidence of hypocalcemia also decreased.

Clinical trial registration: ClinicalTrials.gov (NCT02549391) and JAPIC (JapicCTI-153013).

Health Care Costs in Patients with and without Secondary Hyperparathyroidism in Spain

OBJECTIVE

To analyze the economic burden of secondary hyperparathyroidism (sHPT) in Spain by quantifying differences in costs of pharmacological treatments and associated cardiovascular events (CVE) between renal patients with and without sHPT.

METHODS

We used data collected in the NEFRONA cohort study and obtained treatment and CVE costs from the BOT PLUS database and Hospital Discharge Records in the Spanish Health System (CMBD-H), respectively. We examined data from 2445 renal patients followed during 2 years for chronic kidney disease (CKD) progression and 4 years for CVE, stratifying by presence of sHPT. Patient characteristics, administered treatments and CVE were directly extracted from NEFRONA registries. Dosage for each treatment regimen was assumed based on guidelines and multiplied by official unit costs to obtain treatment costs. Costs of CVE were based on ICD-9-CM.

RESULTS

Prevalence of sHPT in the cohort was 65.6% (63.6; 67.6). Average yearly pharmacological costs for patients without sHPT were 610.33€, while costs were 1483.17€ for sHPT patients (average increase of 143.0%). Two hundred three patients registered CVE, resulting in 4-year average costs of 582.57€ for non-sHPT patients compared to 941.87€ for sHPT patients (61.7% average increase). Bivariate analyses considering presence of dialysis, hypercalcemia or hyperphosphatemia and stratified by sHPT showed higher costs for sHPT patients.

CONCLUSIONS

These results show that sHPT is associated with substantially higher costs of both, pharmacological treatments and associated CVEs. Preventing the development of sHPT with early management in the course of CKD could possibly lead to better health outcomes and cost balance for health care systems.

Paricalcitol versus Calcitriol + Cinacalcet for the Treatment of Secondary Hyperparathyroidism in Chronic Kidney Disease in China: A Cost-Effectiveness Analysis

Background: Chronic Kidney Disease (CKD) is a global chronic disease with increasing prevalence in recent years, particularly CKD accompanied by Secondary Hyperparathyroidism (SHPT) leads to reduced quality of life, increased mortality, a considerable economic burden for patients and society. The aim of this study was to investigate the cost-effectiveness analysis of paricalcitol vs. calcitriol + cinacalcet for CKD patients with SHPT in China in 2020.

Methods: A Markov model was conducted employing data derived from published literature, clinical trials, official sources, and tertiary public hospital data in China, based on a 10-year horizon from the perspective of the healthcare system. Calcitriol + Cinacalcet was used as the reference group. CKD stage 5 (CKD-5) dialysis patients suffering from SHPT were included in the study. Effectiveness was measured in quality-adjusted life years (QALYs). The discount rate (5%) was applied to costs and effectiveness. Sensitivity analysis was performed to confirm the robustness of the findings.

Results: The base case analysis demonstrated that Patients treated with paricalcitol could gain an increase in utility (0.183 QALYs) and require fewer expenditures (6925.612 yuan). One-way sensitivity analysis was performed to showed that impact factors were the price of cinacalcet, the hospitalization costs of patients with paricalcitol and calcitriol, the costs and utilities of hemodialysis and the costs of calcitriol, the costs of paricalcitol regardless of period. Probabilistic simulation analysis displayed when willingness-to-pay was ¥217113, the probability that Paricalcitol was dominant is 96.20%.

Conclusion: The results showed that paricalcitol administrated to treat patients diagnosed with Secondary hyperparathyroidism in Chronic Kidney Disease, compared to calcitriol and cinacalcet, might be dominant in China.

New scenarios in secondary hyperparathyroidism: etelcalcetide. Position paper of working group on CKD-MBD of the Italian Society of Nephrology

Bone mineral abnormalities (defined as Chronic Kidney Disease Mineral Bone Disorder; CKD-MBD) are prevalent and associated with a substantial risk burden and poor prognosis in CKD population. Several lines of evidence support the notion that a large proportion of patients receiving maintenance dialysis experience a suboptimal biochemical control of CKD-MBD. Although no study has ever demonstrated conclusively that CKD-MBD control is associated with improved survival, an expanding therapeutic armamentarium is available to correct bone mineral abnormalities. In this position paper of Lombardy Nephrologists, a summary of the state of art of CKD-MBD as well as a summary of the unmet clinical needs will be provided. Furthermore, this position paper will focus on the potential and drawbacks of a new injectable calcimimetic, etelcalcetide, a drug available in Italy since few months ago.

Nano-lanthanum hydroxide, a novel phosphate binder, for treating hyperphosphatemia: A preclinical study

This study is to determine the pharmacological effects of nano-lanthanum hydroxide (nano-LH) in the treatment of hyperphosphatemia, in comparison with other phosphate binders. Rat models of chronic renal failure and hyperphosphatemia were induced by adenine, which were treated with nano-LH (0.15, 0.10, and 0.05 g/Kg/d), lanthanum carbonate (0.30 g/Kg/d), and normal-size lanthanum hydroxide (0.10 g/Kg/d), respectively. To investigate the therapeutic effects, the serum levels of phosphorus, Scr, Ucr, BUN, UUN, PTH, and other hyperphosphatemia-related biochemical indicators were determined. A novel phosphorus-binding agent, nano-LH, was synthesized herein, which was rod-like particle with the length of 30-50 nm, width of 10-20 nm, and diameter of 5-10 nm. In vitro phosphorus binding experiments showed that nano-LH had better binding rate. Pharmacodynamic experiments confirmed that the therapeutic effects of lanthanum-hydroxide (0.10 g/kg/d) were superior to other existing phosphate binders in rat models of hyperphosphatemia, in lowering the blood phosphate level and improving the renal function. In the term of drug safety, our preliminary results showed that the nano-LH at appropriate dose did not cause death cases in mice, and the serum levels of alkaline phosphatase and lactate dehydrogenase were not significantly changed, indicating good oral safety. Nano-LH has high potency compared with several phosphate binders, which might be a promising therapeutic agent for the treatment of hyperphosphatemia in clinic.

Association of Medicare's Bundled Payment Reform With Changes in Use of Vitamin D Among Patients Receiving Maintenance Hemodialysis: An Interrupted Time-Series Analysis

BACKGROUND & RATIONALE

Medicare's 2011 prospective payment system (PPS) was introduced to curb overuse of separately billable injectable drugs. After epoietin, intravenous (IV) vitamin D analogues are the biggest drug cost drivers in hemodialysis (HD) patients, but the association between PPS introduction and vitamin D therapy has been scarcely investigated.

STUDY DESIGN

Interrupted time-series analyses.

SETTING & PARTICIPANTS

Adult US HD patients represented in the US Renal Data System between 2008 and 2013.

EXPOSURES

PPS implementation.

OUTCOMES

The cumulative dose of IV vitamin D analogues (paricalcitol equivalents) per patient per calendar quarter in prevalent HD patients. The average starting dose of IV vitamin D analogues and quarterly rates of new vitamin D use (initiations/100 person-months) in incident HD patients within 90 days of beginning HD therapy.

ANALYTICAL APPROACH

Segmented linear regression models of the immediate change and slope change over time of vitamin D use after PPS implementation.

RESULTS

Among 359,600 prevalent HD patients, IV vitamin D analogues accounted for 99% of the total use, and this trend was unchanged over time. PPS resulted in an immediate 7% decline in the average dose of IV vitamin D analogues (average baseline dose = 186.5 μg per quarter; immediate change = -13.5 μg [P < 0.001]; slope change = 0.43 per quarter [P = 0.3]) and in the starting dose of IV vitamin D analogues in incident HD patients (average baseline starting dose = 5.22 μg; immediate change = -0.40 μg [P < 0.001]; slope change = -0.03 per quarter [P = 0.03]). The baseline rate of vitamin D therapy initiation among 99,970 incident HD patients was 44.9/100 person-months and decreased over time, even before PPS implementation (pre-PPS β = -0.46/100 person-months [P < 0.001]; slope change = -0.19/100 person-months [P = 0.2]). PPS implementation was associated with an immediate change in initiation levels (by -4.5/100 person-months; P < 0.001).

LIMITATIONS

Incident HD patients were restricted to those 65 years or older.

CONCLUSION

PPS implementation was associated with a 7% reduction in the average dose and starting dose of IV vitamin D analogues and a 10% reduction in the rate of vitamin D therapy initiation.

CKD-MBD management: what is the role of parathyroidectomy? Results from a nationwide survey in Italy

We herein report on a nationwide survey conducted in Italy to investigate the use of parathyroidectomy (PTX). In spite of the availability of newer and more effective drugs to control chronic kidney disease mineral bone disorder (CKD-MBD) biochemical abnormalities, PTX still remains a resource for nephrologists to use. However, observational analyses suggest that in recent years there has been a constant decline in the number of patients undergoing PTX. The reasons are not clear, though the increasing age and number of comorbidities of dialysis patients may partly explain this trend. Poor adherence to guidelines and/or geographical as well as logistic factors may also contribute to the lower use of PTX. The working group on CKD-MBD of the Italian Society of Nephrology launched a nationwide survey to investigate clinical practice patterns for PTX in Italy and identify modifiable factors that may limit accessibility to surgery.

Pharmacokinetics, Biotransformation, and Excretion of [14C]Etelcalcetide (AMG 416) Following a Single Microtracer Intravenous Dose in Patients with Chronic Kidney Disease on Hemodialysis

Etelcalcetide (AMG 416) is a novel synthetic peptide calcium-sensing receptor activator in clinical development as an intravenous calcimimetic for the treatment of secondary hyperparathyroidism in patients with chronic kidney disease (CKD) on hemodialysis. Etelcalcetide is composed of seven d-aminoacids with an l-cysteine linked to a d-cysteine by a disulfide bond. A single intravenous dose of [¹⁴C]etelcalcetide (10 mg; 26.3 kBq; 710 nCi) was administered to patients with CKD on hemodialysis to elucidate the pharmacokinetics, biotransformation, and excretion of etelcalcetide in this setting. Blood, dialysate, urine, and feces were collected to characterize the pharmacokinetics, biotransformation product profiles, mass balance, and formation of anti-etelcalcetide antibodies. Accelerator mass spectrometry was necessary to measure the microtracer quantities of C-14 excreted in the large volumes of dialysate and other biomatrices. An estimated 67 % of the [¹⁴C]etelcalcetide dose was recovered in dialysate, urine, and feces 176 days after dose administration. Etelcalcetide was primarily cleared by hemodialysis, with approximately 60 % of the administered dose eliminated in dialysate. Minor excretion was observed in urine and feces. Biotransformation resulted from disulfide exchange with endogenous thiols, and preserved the etelcalcetide d-amino acid backbone. Drug-related radioactivity circulated primarily as serum albumin peptide conjugate (SAPC). Following removal of plasma etelcalcetide by hemodialysis, re-equilibration occurred between SAPC and l-cysteine present in blood to partially restore the etelcalcetide plasma concentrations between dialysis sessions. No unanticipated safety signals or anti-etelcalcetide or anti-SAPC antibodies were detected.

Treatment of secondary hyperparathyroidism: the clinical utility of etelcalcetide

Secondary hyperparathyroidism (SHPT), a very frequent, severe, and worsening complication of chronic kidney disease, is characterized by high serum parathyroid hormone (PTH), parathyroid gland hyperplasia, and disturbances in mineral metabolism. Clinically, SHPT shows renal osteodystrophy, vascular calcification, cardiovascular damage, and fatal outcome. Calcium-sensing receptor (CaSR) is the main physiological regulator of PTH secretion; its activation by calcium rapidly inhibits PTH. Another important player in regulating mineral metabolism is vitamin D receptor (VDR), which is under the influence of vitamin D and influences the intestinal absorption of calcium and phosphate, PTH gene expression, and bone calcium mobilization. Serum phosphate levels influence fibroblast growth factor 23 (FGF-23) production, a phosphatonin that modulates serum phosphate reabsorption, PTH synthesis, and vitamin D production. Current therapeutic approaches consist of 1) phosphate intake control by diet or phosphate binders, 2) vitamin D by VDR activation, and 3) calcimimetic agents that activate CaSR. Recently, a new long-acting peptide (etelcalcetide) belonging to the calcimimetics class was approved for intravenous use in hemodialysis patients with SHPT. Etelcalcetide binds directly to CaSR, by a sulfide bond, inhibiting the production and secretion of PTH by parathyroid glands. After intravenous administration in rats, etelcalcetide is quickly distributed to the tissues and eliminated by kidneys, while in uremic animals the nonrenal excretion is only 1.2%. In hemodialysis patients, the treatment itself is the main route of elimination. Etelcalcetide in hemodialysis patients with SHPT was more effective than placebo and cinacalcet, with a PTH reduction of >30% in 76% of patients with etelcalcetide versus 10% with placebo. Particular attention was paid to the safety of the drug; the most common adverse event was asymptomatic blood calcium reduction, similar to cinacalcet, while gastrointestinal symptoms were less frequent. This promising new drug available for better control of SHPT will, together with drugs already in use, optimize the treatment to normalize the biochemical parameters.

Drug disposition model of radiolabeled etelcalcetide in patients with chronic kidney disease and secondary hyperparathyroidism on hemodialysis

Etelcalcetide (AMG 416) is an allosteric activator of the calcium-sensing receptor for treatment of secondary hyperparathyroidism in patients with chronic kidney disease (CKD) on hemodialysis. To characterize the time course of etelcalcetide in different matrices (plasma, dialysate, urine, and feces), a drug disposition model was developed. Nonlinear mixed-effect modeling was used to describe data from six adults with CKD on hemodialysis who received a single intravenous dose of [¹⁴C]etelcalcetide (10 mg; 710 nCi) after hemodialysis (study NCT02054572). A three-compartment model with the following attributes adequately described the observed concentration-time profiles of etelcalcetide in the different matrices: biotransformation in the central compartment; elimination in dialysate, urine, and feces; and a nonspecific elimination process. The terminal half-life of total C-14 in plasma was approximately 56 days. The ratio of conjugation-deconjugation rate constants between etelcalcetide and biotransformed products was 11.3. Simulations showed that three hemodialysis sessions per week for 52 weeks would contribute to 60.1% of the total clearance of etelcalcetide following single-dose intravenous etelcalcetide administration. Minimal amounts were eliminated in urine (2.5%) and feces (5.7%), whereas nonspecific elimination accounted for 31.2% of total elimination. In addition to removal of etelcalcetide, ~10% of small-molecular weight biotransformed products was estimated to have been removed through hemodialysis and in urine. This model provided a quantitative approach to describe biotransformation, distribution, and elimination of etelcalcetide, a unique synthetic D-amino acid peptide, in the relevant patient population.

Clinicopathological correlates of hyperparathyroidism

Hyperparathyroidism is a common endocrine disorder with potential complications on the skeletal, renal, neurocognitive and cardiovascular systems. While most cases (95%) occur sporadically, about 5% are associated with a hereditary syndrome: multiple endocrine neoplasia syndromes (MEN-1, MEN-2A, MEN-4), hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH-1, FHH-2, FHH-3), familial hypercalciuric hypercalcaemia, neonatal severe hyperparathyroidism and isolated familial hyperparathyroidism. Recently, molecular mechanisms underlying possible tumour suppressor genes (MEN1, CDC73/HRPT2, CDKIs, APC, SFRPs, GSK3β, RASSF1A, HIC1, RIZ1, WT1, CaSR, GNA11, AP2S1) and proto-oncogenes (CCND1/PRAD1, RET, ZFX, CTNNB1, EZH2) have been uncovered in the pathogenesis of hyperparathyroidism. While bi-allelic inactivation of CDC73/HRPT2 seems unique to parathyroid malignancy, aberrant activation of cyclin D1 and Wnt/β-catenin signalling has been reported in benign and malignant parathyroid tumours. Clinicopathological correlates of primary hyperparathyroidism include parathyroid adenoma (80-85%), hyperplasia (10-15%) and carcinoma (<1-5%). Secondary hyperparathyroidism generally presents with diffuse parathyroid hyperplasia, whereas tertiary hyperparathyroidism reflects the emergence of autonomous parathyroid hormone (PTH)-producing neoplasm(s) from secondary parathyroid hyperplasia. Surgical resection of abnormal parathyroid tissue remains the only curative treatment in primary hyperparathyroidism, and parathyroidectomy specimens are frequently encountered in this setting. Clinical and biochemical features, including intraoperative PTH levels, number, weight and size of the affected parathyroid gland(s), are crucial parameters to consider when rendering an accurate diagnosis of parathyroid proliferations. This review provides an update on the expanding knowledge of hyperparathyroidism and highlights the clinicopathological correlations of this prevalent disease.