Clinical outcomes in secondary hyperparathyroidism and the potential role of calcimimetics

Etelcalcetide Inhibits the Progression of Left Atrial Volume Index Compared to Alfacalcidol in Hemodialysis Patients

INTRODUCTION

Increased left atrial (LA) size is a risk factor for cardiovascular events and all-cause mortality. It is closely related to left ventricular hypertrophy and chronic volume overload, both of which are common in hemodialysis. Calcimimetic treatment with etelcalcetide (ETL) previously showed an inhibitory effect on left ventricular mass index (LVMI) progression in this population.

METHODS

This is a post hoc analysis of the EtECAR-HD trial, where 62 patients were randomized to ETL or alfacalcidol (ALFA) for 1 year. LA volume index (LAVI) was measured using cardiac magnetic resonance imaging. The aim of the study was to investigate whether ETL was associated with a change of LAVI.

RESULTS

Median baseline levels of LAVI were 40 mL/m2 (31, 54 IQR) in the ETL group and 36 mL/m2 (26, 46 IQR) in the ALFA group. In the ITT population, the change of LAVI was 5.0 mL/m2 [95% CI: -0.04, 10] lower under ETL, compared to ALFA (p = 0.052, R2adj = 0.259). In the PP population, the difference in LAVI changes widened to 5.8 [95% CI: 0.36, 11], p = 0.037, R2adj = 0.302). Secondary analysis showed that the study delta of LVMI was correlated with the LAVI delta (r = 0.387) and that an inclusion of LVMI delta in the ANCOVA model mediated the effect on LAVI delta to β = 3.3 [95% CI: -0.04, 10] (p = 0.2, R2adj = 0.323). The same could not be observed for parameters assessing the volume status.

CONCLUSIONS

The analysis indicates that ETL could inhibit LAVI progression compared with ALFA. This effect was mediated by the change of LVMI.

Health state utilities associated with major clinical events in the context of secondary hyperparathyroidism and chronic kidney disease requiring dialysis

BACKGROUND

Patients with chronic kidney disease (CKD) and secondary hyperparathyroidism (SHPT) who require dialysis are at increased risk for cardiovascular events and bone fractures. To assist in economic evaluations, this study aimed to estimate the disutility of these events beyond the impact of CKD and SHPT.

METHODS

A basic one-year health state was developed describing CKD and SHPT requiring dialysis. Further health states added acute events (cardiovascular events, fractures, and surgical procedures) or chronic post-event effects. Acute health states described a year including an event, and chronic health states described a year subsequent to an event. General population participants in Canada completed time trade-off interviews from which utilities were derived. Pairwise comparisons were made between the basic state and event, and between comparable health states.

RESULTS

A total of 199 participants (54.8% female; mean age = 46.3 years) completed interviews. Each health state had ≥130 valuations. The mean (SD) utility of the basic health state was 0.60 (0.34). For acute events, mean utility differences versus the basic state were: myocardial infarction, -0.06; unstable angina, -0.05; peripheral vascular disease (PVD) with amputation, -0.33; PVD without amputation, -0.11; heart failure, -0.14; stroke, -0.30; hip fracture, -0.14; arm fracture, -0.04; parathyroidectomy, +0.02; kidney transplant, +0.06. Disutilities for chronic health states were: stable angina, -0.09; stroke, -0.27; PVD with amputation, -0.30; PVD without amputation, -0.12; heart failure, -0.14.

CONCLUSIONS

Cardiovascular events and fractures were associated with lower utility scores, suggesting a perceived decrease in quality of life beyond the impact of CKD and SHPT.

Cinacalcet: a pharmacoeconomic review of its use in secondary hyperparathyroidism in end-stage renal disease

This article provides an overview of the clinical profile of the calcimimetic agent cinacalcet (Mimpara®, Sensipar®) in the treatment of patients with secondary hyperparathyroidism (SHPT) undergoing dialysis for end-stage renal disease (ESRD), followed by a comprehensive review of pharmacoeconomic analyses with cinacalcet in this patient population. Most patients with ESRD undergoing dialysis develop SHPT, which is associated with disturbances in bone mineral metabolism and the development of fractures, cardiovascular disease and other clinical events. Standard treatment of SHPT includes phosphate binders and active vitamin D derivatives. However, standard treatment alone seldom achieves recommended target plasma or serum levels of parathyroid hormone (PTH), calcium and phosphorous. The addition of cinacalcet to standard therapy in patients with SHPT undergoing dialysis for ESRD improves the likelihood of achieving target biochemical levels compared with standard therapy alone. On the basis of association studies, improvements in these intermediate endpoints are likely to reduce the risk of clinical events, such as fractures and cardiovascular disease. Therefore, part of the acquisition cost of cinacalcet is likely to be offset by reductions in other healthcare resource use, such as reductions in costs associated with a lower likelihood of clinical events, as well as potential reductions in dosages of standard treatment. A number of pharmacoeconomic analyses across various country settings indicate that cinacalcet plus standard therapy is cost effective relative to standard therapy alone if dialysis costs are excluded, or that early initiation of cinacalcet is cost effective compared with delaying cinacalcet treatment until PTH levels become very uncontrolled. However, across analyses with cinacalcet, results were variable and not always favourable. This wide range of results stems from differences in selection of data sources used to populate the models, regional differences in healthcare resource use and costs, as well as other factors. Future cost-effectiveness analyses with cinacalcet should incorporate data on hard clinical outcomes from the EVOLVE study once this information becomes available.

Secondary hyperparathyroidism: pathogenesis, disease progression, and therapeutic options

Secondary hyperparathyroidism (SHPT) is a challenge frequently encountered in the management of patients with chronic kidney disease (CKD). Downregulation of the parathyroid vitamin D and calcium-sensing receptors represent critical steps that lead to abnormalities in mineral metabolism: high phosphate, low calcium, and vitamin D deficiency. These imbalances result in parathyroid hyperplasia and contribute to vascular calcification. New studies have established a central role for fibroblast growth factor 23 (FGF-23) in the regulation of phosphate-vitamin D homeostasis. FGF-23 concentration increases in CKD and contributes to SHPT. Achieving current targets for the key mineral parameters in the management of SHPT set by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines can be challenging. This review summarizes the current understanding and evidence supporting strategies for SHPT treatment in CKD patients. Treatment should include a combination of dietary phosphorus restriction, phosphate binders, vitamin D sterols, and calcimimetics. Parathyroidectomy is effective in suitable candidates refractory to medical therapy and the standard against which new approaches should be measured. Future strategies may focus on the stimulation of apoptotic activity of hyperplastic parathyroid cells.