Population Pharmacokinetics of the Novel Adenosine A2A Antagonist/Inverse Agonist KW-6356 and Its Active Metabolite Following Single and Multiple Oral Administration in Healthy Individuals and Patients with Parkinson's Disease

KW-6356 is a selective antagonist and inverse agonist of the adenosine A2A receptor. The primary aim of the present analysis was to characterize the pharmacokinetics (PK) of KW-6356 and its active metabolite M6 in healthy subjects and patients with Parkinson's disease (PD). We pooled concentration-time data from healthy subjects and patients with PD who were administered KW-6356. Using these data, we developed a population PK model by sequentially fitting the KW-6356 parameters followed by the M6 parameters. A first-order absorption with a 1-compartment model for KW-6356 and a 1-compartment model for M6 best described the profiles. The covariates included in the final models were food status (fed/fasted/unknown) on first-order absorption rate constant, baseline serum albumin level on apparent clearance of KW-6356, and baseline body weight on apparent volume of distribution of KW-6356 and apparent clearance of M6. No covariate had a clinically meaningful impact on KW-6356 or M6 exposure.

Influence of hemodialysis on regadenoson clearance in an in vitro hemodialysis model

BACKGROUND

Regadenoson is a novel pharmacological stress agent whose disposition during hemodialysis is not known. The purpose of this study was to determine the clearance of regadenoson under varying dialytic conditions using an in vitro hemodialysis model.

METHODS AND RESULTS

Whole human blood was used to analyze the effect of hemodialysis on the clearance of regadenoson. Regadenoson transmembrane clearance (CLD) was assessed for both a standard permeability and a high permeability polysulfone hemodialyzer with blood/dialysate flow rates of 300/600 and 400/800 mL/min. A two-tailed, paired Student's t test was used to compare regadenoson CLD between hemodialyzer types and flow rates. The mean ± SD regadenoson CLD values ranged between 62.5 ± 11.8 and 89.1 ± 24.0 mL/min for all dialytic conditions. There was no significant difference in regadenoson CLD between hemodialyzer types and flow rates (p > .05).

CONCLUSIONS

Hemodialysis enhances the clearance of regadenoson independent of hemodialyzer permeability and blood/dialysate flow rate. This clearance is modest relative to total body clearance and is unlikely to produce a clinically significant outcome.

Regadenoson use in chronic kidney disease and end-stage renal disease: A focused review

Regadenoson is a selective A2A adenosine receptor agonist that has been approved as a vasodilator stress agent with single-photon emission-computed tomography (SPECT) myocardial perfusion imaging (MPI). Since its approval by the Food and Drug Administration (FDA) in 2008, it has become the most commonly used pharmacologic stress agent with SPECT-MPI. Given that it is predominantly renally excreted, its use in patients with chronic kidney disease has been the subject of active post-marketing clinical research. Until recently, prescribing information regarding the use of regadenoson in patients with end-stage renal disease (ESRD) was not defined in the package insert. Based on accumulating data since its initial approval, the FDA has recently outlined the use of regadenoson in patients with ESRD in a label update on January 17, 2017. In this review, we discuss the evidence leading to the recent label update, focusing on the pharmacokinetics of regadenoson in patients with impaired kidney function, the safety and tolerability of regadenoson in patients with chronic kidney disease and ESRD, and the prognostic value of regadenoson stress MPI in this patient population.