Impact of Cinacalcet Hydrochloride on the Achievement of the Japanese Society for Dialysis Therapy (JSDT) Guideline Targets: A post-hoc Analysis of the KRN1493 Study

First-in-Human Phase I Study of the Novel Injectable Calcimimetic Agent Upacicalcet in Healthy Adult Japanese Participants

Background and Objective

Upacicalcet sodium hydrate is a novel small-molecule calcimimetic and has potential as a therapeutic agent for secondary hyperparathyroidism. We assessed the pharmacokinetics, pharmacodynamics, safety, and tolerability of a single intravenous dose of upacicalcet in Japanese healthy adults.

Method

This was a single-center, double-blinded, randomized, placebo-controlled, dose-escalation study. For each cohort, eight subjects were randomly assigned at a ratio of 3:1 to receive a single injection of placebo or upacicalcet 0.01, 0.1, 1.0, or 2.5 mg.

Result

The plasma concentration of upacicalcet increased in a dose-dependent manner. Upacicalcet rapidly disappeared from plasma after administration. The half-life of upacicalcet was approximately 1–2 h. The major excretion route of upacicalcet was via urine. Serum intact parathyroid hormone decreased in accordance with the upacicalcet dose, from the lowest dose of 0.01 mg. Gastrointestinal disorders occurred in one patient in the 1.0 mg group and in five patients in the 2.5 mg group. All adverse events were nonserious, and no symptomatic hypocalcemia occurred.

Conclusion

This study showed that upacicalcet acted as a calcimimetic and was excreted in the urine unchanged with little metabolism. Moreover, upacicalcet is a small molecule and has a small volume of distribution. In addition, less than 50% of upacicalcet binds to human plasma proteins. These findings suggest that upacicalcet administered to patients undergoing hemodialysis might be expected to have a long excretion period and sustained pharmacological effect.

Phase 2b study of evocalcet (KHK7580), a novel calcimimetic, in Japanese patients with secondary hyperparathyroidism undergoing hemodialysis: A randomized, double-blind, placebo-controlled, dose-finding study

Background

Evocalcet has been developed as a new calcimimetic agent for hemodialysis (HD) patients with secondary hyperparathyroidism (HDSHPT), eliciting fewer gastrointestinal symptoms and drug interactions. We evaluated the efficacy, safety, and optimal starting dose of evocalcet in HDSHPT.

Methods

In this 3-week, Phase 2b, randomized, double-blind, placebo-controlled, multicenter, parallel-group, dose-finding study, Japanese HDSHPT with intact parathyroid hormone (iPTH) ≥240 pg/mL and serum calcium level corrected for albumin ≥8.4 mg/dL were randomized to evocalcet 0.5, 1, 2 mg/day administered orally or placebo under double-blind conditions, and cinacalcet 25 mg/day (open-label conditions).

Results

In total, 152 HDSHPT were randomized. The mean ± standard deviation (median, interquartile range) of percent changes in iPTH from baseline to end of treatment were −8.40±25.43% (−12.16, 39.60), −10.56±22.86% (−14.24, 27.85), and −20.16±34.23% (−23.83, 39.05) in the evocalcet 0.5, 1, and 2 mg/day groups and 5.44±25.85% (3.52, 35.39) and −25.86±27.76% (−29.79, 34.15) in the placebo and cinacalcet groups, respectively. The dose-response profile for each evocalcet group vs placebo showed statistically significant differences for all contrast patterns. Whole PTH, corrected calcium, ionized calcium, phosphorus, and intact fibroblast growth factor 23 decreased after treatment initiation in the evocalcet and cinacalcet groups. Adverse events were observed in 30%–50% of patients (all groups). Incidence of adverse events was similar among all groups except for decreased calcium, which occurred more frequently in the evocalcet 2 mg and cinacalcet groups.

Conclusions

The dose response and safety of all administered doses of evocalcet were confirmed, as well as the efficacy of evocalcet ≥1 mg in a strictly Japanese sample of HDSHPT. Therefore, evocalcet 1 mg was considered appropriate as an initial dose for HDSHPT.

Pharmacokinetics of evocalcet in secondary hyperparathyroidism patients receiving hemodialysis: first-in-patient clinical trial in Japan

Purpose

Cinacalcet is a positive allosteric modulator of calcium-sensing receptors in the parathyroid gland and an effective treatment for secondary hyperparathyroidism. However, this agent has considerable side effects and dosage limitations, which impair effective treatment. Therefore, we investigated the pharmacokinetics, pharmacodynamics, and safety of the novel calcimimetic, evocalcet.

Patients and methods

This was a multicenter, open-label study of single oral doses of 1, 4, and 12 mg evocalcet using an intrapatient dose escalation protocol in 29 Japanese secondary hyperparathyroidism patients receiving hemodialysis. Pharmacokinetics was assessed by plasma evocalcet concentrations. Pharmacodynamic evaluations consisted of measuring intact parathyroid hormone, serum corrected calcium, and fibroblast growth factor 23 concentrations. Safety and tolerability were evaluated by the analysis of adverse events (AEs).

Results

After a single 1-, 4-, or 12-mg dose, plasma evocalcet levels increased dose proportionally in a linear manner. Pharmacodynamic analyses showed that evocalcet effectively reduced intact parathyroid hormone and serum corrected calcium levels in a dose-dependent manner. AEs occurred in 31.0%, 28.6%, and 38.5% of patients receiving a single dose of 1, 4, or 12 mg, respectively. Most AEs were mild in severity.

Conclusion

Evocalcet is effective in the short term, has linear pharmacokinetics, and is well tolerated as observed by the low incidence of AEs.

Pharmacodynamics of evocalcet for secondary hyperparathyroidism in Japanese hemodialysis patients

BACKGROUND

This study investigated the pharmacokinetics, pharmacodynamics, and safety of multiple doses of evocalcet in Japanese secondary hyperparathyroidism (SHPT) patients receiving hemodialysis.

METHODS

In this multicenter, open-label study, conducted between August 2013 and March 2014, 27 patients received multiple doses of 1 and 4 mg evocalcet for 14 days, followed by an extension period of multiple doses of 8 and 12 mg evocalcet for 7 days using an intra-patient dose escalation protocol. Pharmacodynamic parameters consisted of measurement of intact parathyroid hormone (PTH), serum-corrected calcium, serum phosphorus and intact fibroblast growth factor 23 concentrations. Safety was assessed by analysis of adverse events.

RESULTS

Plasma evocalcet levels reached steady state 3 days after the first day of administration. Pharmacodynamic analyses showed that evocalcet effectively reduced intact PTH and serum-corrected calcium levels. Adverse events (AEs) occurred in 29.6 and 62.5% of patients receiving multiple doses of 1 or 4 mg, respectively. The AE 'blood calcium decreased' occurred in eight patients (33.0%) after multiple doses of 4 mg. All events were mild, except for one patient with a moderate AE (abnormal liver function) and one patient with a severe adverse drug reaction (blood calcium decreased).

CONCLUSION

Multiple doses of evocalcet reduced intact PTH levels with a concomitant decrease in serum calcium levels. Evocalcet was well tolerated in SHPT patients receiving hemodialysis.

A Japanese approach for CKD-MBD

Disturbances in mineral and bone metabolism have a critical role in the pathogenesis of cardiovascular complications in patients with chronic kidney disease (CKD). The term ‘renal osteodystrophy' has recently been replaced by ‘CKD-mineral and bone disorder (CKD-MBD)', which includes abnormalities in bone and mineral metabolism and vascular calcification. The Japanese Society for Dialysis Therapy clinical practice guideline for the management of secondary hyperparathyroidism in chronic dialysis patients was originally published in Japanese in 2006, then in English in 2008. During the past 5 years, this first guideline has contributed to a considerably better understanding and control of secondary hyperparathyroidism in CKD patients by physicians, other medical professionals, and the patients themselves. However, since its publication several new therapeutic modalities have become available for Japanese dialysis patients, which added more evidence to this area. Thus, we revised the guideline to include several new policies, and the new guideline was published in Japanese in 2012. This article contains the new guideline text, and clinical significance of CKD-MBD in Japan.

Decreases in PTH in Japanese hemodialysis patients with secondary hyperparathyroidism: associations with changing practice patterns

BACKGROUND AND OBJECTIVES

Control of serum concentrations of calcium (Ca), phosphorus (P), and parathyroid hormone (PTH) is essential for management of secondary hyperparathyroidism (SHPT).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a planned interim analysis of a longitudinal cohort study. The settings are dialysis facilities in Japan. Eligible patients comprise all those who were receiving hemodialysis at one of 86 participating facilities and who have SHPT. Using data from a random sample (n = 3276) of the participants from January 2008 through June 2009, we measured changes in the percentages of patients who were within the national guideline-specified target ranges of Ca (8.4 to 10 mg/dl), P (3.5 to 6.0 mg/dl), and intact PTH (iPTH) (60 to 180 pg/ml), and changes in prescriptions of drugs targeting SHPT. We used regression models to identify factors affecting the achievement of the guideline-specified targets.

RESULTS

There were no notable changes in the percentage of patients who were within the guideline for Ca, P, or both. The percentage who were within the iPTH guideline increased from 14.5% to 43.3% (P < 0.001). There were no remarkable changes in the percentage of patients receiving vitamin D or phosphate binders. The percentage who received cinacalcet increased from 0% to 29%. Prescription of cinacalcet was associated with improvement or target-achievement for iPTH and for Ca by 16.8 percentage points (95% CI: 8.1 to 17.0) and by 12.6 percentage points (13.7 to 19.9), respectively.

CONCLUSIONS

In the routine care of hemodialysis patients, increasing use of cinacalcet was associated with better control of SHPT.

Cinacalcet effectively reduces parathyroid hormone secretion and gland volume regardless of pretreatment gland size in patients with secondary hyperparathyroidism

BACKGROUND AND OBJECTIVES

Cinacalcet is effective in reducing serum parathyroid hormone (PTH) in patients with secondary hyperparathyroidism. However, it has not been proven whether parathyroid gland size predicts response to therapy and whether cinacalcet is capable of inducing a reduction in parathyroid volume.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This 52-week, multicenter, open-label study enrolled hemodialysis patients with moderate to severe secondary hyperparathyroidism (intact PTH >300 pg/ml). Doses of cinacalcet were adjusted between 25 and 100 mg to achieve intact PTH <180 pg/ml. Ultrasonography was performed to measure the parathyroid gland size at baseline, week 26, and week 52. Findings were also compared with those of historical controls.

RESULTS

Of the 81 subjects enrolled, 56 had parathyroid glands smaller than 500 mm(3) (group S) and 25 had at least one enlarged gland larger than 500 mm(3) (group L). Treatment with cinacalcet effectively decreased intact PTH by 55% from baseline in group S and by 58% in group L. A slightly greater proportion of patients in group S versus group L achieved an intact PTH <180 pg/ml (46 versus 32%) and a >30% reduction from baseline (88 versus 78%), but this was not statistically significant. Cinacalcet therapy also resulted in a significant reduction in parathyroid gland volume regardless of pretreatment size, which was in sharp contrast to historical controls (n = 87) where parathyroid gland volume progressively increased with traditional therapy alone.

CONCLUSIONS

Cinacalcet effectively decreases serum PTH levels and concomitantly reduces parathyroid gland volume, even in patients with marked parathyroid hyperplasia.