A Decision-Analytic Model to Assess the Cost-Effectiveness of Etelcalcetide vs. Cinacalcet

Pharmacogenetic and safety analysis of cinacalcet hydrochloride in healthy Chinese subjects

BACKGROUND

Our study aims to explore the effect of genetics on the pharmacodynamics (PD) and pharmacokinetics (PK) of cinacalcet in healthy Chinese subjects; to investigate the effect of dietary factors on cinacalcet, and to evaluate the safety of cinacalcet under fasting and non-fasting conditions using a bioequivalence trial.

METHODS

We investigated the relationship of cinacalcet PK with single nucleotide polymorphisms (SNPs) of CYP3A4, CYP1A2 and CYP2D6, and of cinacalcet PD with SNPs of calcium-sensitive receptors (CASR) and vitamin D receptors (VDR) in 65 healthy Chinese subjects recruited to participate in this study. Our study was a phase I, open-label, randomized, two-period, two-sequence crossover, a single-center clinical study designed under both fasting and non-fasting conditions to investigate the effect of dietary factors on cinacalcet. Plasma cinacalcet concentrations were analyzed using a validated HPLC-MS/MS assay. Clinical laboratory tests evaluated safety. Thirteen SNPs of CASR, VDR, and CYP genes were selected for pharmacogenetic analysis.

RESULTS

CYP3A4 rs4646437 was found to be associated with the PK of cinacalcet under fasting conditions (P<0.01). Subjects carrying T alleles of rs4646437 appeared to metabolize cinacalcet poorly. The C_max and AUC of subjects in the non-fasting group were significantly higher (P<0.0001) than those in the fasting group. The T_max, CL/F, and Vd/F in the fasting group were significantly higher (P<0.0001) than those in the non-fasting group. In the fasting group, the geometric least square mean ratios (T/R) of the C_max and AUC_0-t were 109.89% and 105.33%, and the corresponding 90% CIs were 98.36-122.79% and 98.04-113.15%, respectively. In the non-fasting group, the T/R of the C_max and AUC_0-t were 100.74% and 99.09%, and the corresponding 90% CIs were 92.65-109.54% and 94.79-103.58%, respectively. All adverse events (AEs) were mild, and no serious adverse events (SAEs) occurred during the bioequivalence trial.

CONCLUSIONS

Following our investigation, we reached the following conclusions: CYP3A4 rs4646437 may affect cinacalcet PK; the reference and test preparations of cinacalcet were bioequivalent under fasting and non-fasting conditions and were safe to use; and dietary factors had a significant effect on the PK of cinacalcet, in that exposure to the drug increased when cinacalcet was taken after eating.

New Intravenous Calcimimetic Agents: New Options, New Problems. An Example on How Clinical, Economical and Ethical Considerations Affect Choice of Treatment

BACKGROUND

Dialysis treatment is improving, but several long-term problems remain unsolved, including metabolic bone disease linked to chronic kidney disease (CKD-MBD). The availability of new, efficacious but expensive drugs (intravenous calcimimetic agents) poses ethical problems, especially in the setting of budget limitations.

METHODS

Reasons of choice, side effects, biochemical trends were discussed in a cohort of 15 patients (13% of the dialysis population) who stared treatment with intravenous calcimimetics in a single center. All patients had previously been treated with oral calcimimetic agents; dialysis efficacy was at target in 14/15; hemodiafiltration was employed in 10/15. Median Charlson Comorbidity Index was 8. The indications were discussed according to the principlist ethics (beneficience, non maleficience, justice and autonomy). Biochemical results were analyzed to support the clinical-ethical choices.

RESULTS

In the context of a strict clinical and biochemical surveillance, the lack of side effects ensured "non-maleficence"; efficacy was at least similar to oral calcimimetic agents, but tolerance was better. Autonomy was respected through a shared decision-making model; all patients appreciated the reduction of the drug burden, and most acknowledged better control of their biochemical data. The ethical conflict resides in the balance between the clinical "beneficience, non-maleficience" advantage and "justice" (economic impact of treatment, potentially in attrition with other resources, since the drug is expensive and included in the dialysis bundle). The dilemma is more relevant when a patient's life expectancy is short (economic impact without clear clinical advantages), or when non-compliance is an issue (unclear advantage if the whole treatment is not correctly taken).

CONCLUSIONS

In a context of person-centered medicine, autonomy, beneficence and non-maleficence should weight more than economic justice. While ethical discussions are not aimed at finding "the right answer" but asking "the right questions", this example can raise awareness of the importance of including an ethical analysis in the choice of "economically relevant" drugs.

Secondary and Tertiary Hyperparathyroidism: A Narrative Review

End-stage renal disease is often complicated by the occurrence of secondary and eventually tertiary hyperparathyroidism, characterized by increased parathormone, calcium, and phosphate concentrations. Related symptoms include pruritus and osteodynia, concentration difficulties, and feelings of depression may be present. In the long-term, end-stage renal disease patients with hyperparathyroidism have an increased risk of all-cause and cardiovascular mortality. Among treatment options are vitamin D supplements, phosphate binders, calcimimetics, and surgical parathyroidectomy. Determining the optimal treatment for the individual patient is challenging for nephrologists and endocrine surgeons. This review resumes the pathogenesis of hyperparathyroidism, clinical presentation, required diagnostic work-up, and discusses indications for the available treatment options for patients with secondary and tertiary hyperparathyroidism.

Enhanced dissolution and oral bioavailbility of cinacalcet hydrochlorde nanocrystals with no food effect

This study was aimed at improving oral bioavailbility and reducing the food effect of cinacalcet hydrochlorde (CINA), a poorly soluble drug for the treatment of chronic kidney disease, by preparing its nanocrystals (NCs) utilizing the precipitation-ultrasonication method. Based on the single factor method and Box-Behnken design, with the particle size and polydispersity index (PDI) as indexes, the optimal formulation was achieved. It was investigated that the particle size and PDI of the NCs prepared on the basis of optimal formulation were 244 ± 2 nm and 0.168 ± 0.001, respectively. The NCs were solidificated by lyophilization. Scanning electron microscopy, differential scanning calorimetry and x-ray powder diffraction were used to characterize the CINA-NCs, and there was no crystalline change during preparation and lyophilization. The CINA-NCs capsules prepared with 30% (w/v) MCC, 8% (w/v) CCNa and 2% (w/v) talcum powder by orthogonal experimental design presented an enhanced in vitro dissolution rate in four media compared with commercial tablets Sensipar® and raw material. The raw material, blank NCs and CINA-NCs were confirmed to be non-toxic to Caco-2 cells when the drug concentration was below 250 μg ml^-1. In the in vivo pharmacokinetic study, the C_max (the peak concentration of CINA in plasma) and AUC_0-t (area under curve by trapezoidal area method) of the CINA-NCs capsules were approximately 1.90-fold and 1.64-fold greater than that of Sensipar® in the fasted state. Overall, this nanotechnology is a promising way to optimize the dosage form of CINA oral administration.

Treatment of secondary hyperparathyroidism in patients on hemodialysis using a novel synthetic peptide calcimimetic, etelcalcetide: a short-term clinical study

Objective

Secondary hyperparathyroidism (SHPT) is a major complication in patients with chronic kidney disease (CKD). SHPT is related to chronic kidney disease-mineral bone disorder, leading to increased morbidity and mortality. Etelcalcetide is intravenously administered at the end of hemodialysis (HD). Etelcalcetide differs from the oral calcimimetic cinacalcet because it reduces gastrointestinal adverse events, thereby improving therapeutic effects. Etelcalcetide has only been approved by the U.S. Food and Drug Administration for several months. Therefore, there have only been a few reports regarding treatment of SHPT using etelcalcetide. This study aimed to evaluate the efficacy of etelcalcetide in patients on HD with SHPT.

Methods

Nine patients on HD (four men and five women, aged 58 ± 10 years) were enrolled in this study. All of the patients received etelcalcetide (5–10 mg, three times a week after HD). The observation period was 4.4 ± 1.0 months.

Results

All of the patients showed a significant reduction in serum parathyroid hormone levels during the observation period (−59% ± 20%). No significant adverse effects were observed.

Conclusions

Although this study had an uncontrolled small group and a short observation period, our results suggest that etelcalcetide could be a promising agent for SHPT treatment.

Role of etelcalcetide in the management of secondary hyperparathyroidism in hemodialysis patients: a review on current data and place in therapy

Secondary hyperparathyroidism (sHPT) is a frequently occurring severe complication of advanced kidney disease. Its clinical consequences include extraskeletal vascular and valvular calcifications, changes in bone metabolism resulting in renal osteodystrophy, and an increased risk of cardiovascular morbidity and mortality. Calcimimetics are a cornerstone of parathyroid hormone (PTH)-lowering therapy, as confirmed by the recently updated 2017 Kidney Disease: Improving Global Outcomes chronic kidney disease – mineral and bone disorder clinical practice guidelines. Contrary to calcitriol or other vitamin D-receptor activators, calcimimetics reduce PTH without increasing serum-calcium, phosphorus, or FGF23 levels. Etelcalcetide is a new second-generation calcimimetic that has been approved for the treatment of sHPT in adult hemodialysis patients. Whereas the first-generation calcimimetic cinacalcet is taken orally once daily, etelcalcetide is given intravenously thrice weekly at the end of the hemodialysis session. Apart from improving drug adherence, etelcalcetide has proven to be more effective in lowering PTH when compared to cinacalcet, with an acceptable and comparable safety profile. The hope for better gastrointestinal tolerance with intravenous administration did not come true, as etelcalcetide did not significantly mitigate the adverse gastrointestinal effects associated with cinacalcet. Enhanced adherence and strong reductions in PTH, phosphorus, and FGF23 could set the stage for a future large randomized controlled trial to demonstrate that improved biochemical control of mineral metabolism with etelcalcetide in hemodialysis patients translates into cardiovascular and survival benefits and better health-related quality of life.