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Published in: Clinical Pharmacokinetics 9/2023

Open Access 28-06-2023 | Pharmacokinetics | Original Research Article

Pharmacokinetics, Metabolism, and Excretion of Intravenous [14C]Difelikefalin in Healthy Subjects and Subjects on Hemodialysis

Authors: Jeffrey G. Stark, Patrick K. Noonan, Robert H. Spencer, Sarbani Bhaduri, Stephen J. O’Connor, Frédérique Menzaghi

Published in: Clinical Pharmacokinetics | Issue 9/2023

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Abstract

Background and Objective

Difelikefalin, a selective kappa-opioid receptor agonist, is the first approved treatment for moderate-to-severe pruritus in patients with end-stage renal disease (ESRD) on hemodialysis (HD) in the USA and Europe. The purpose of this open-label study was to investigate the pharmacokinetics and disposition of [14C]difelikefalin following a single intravenous dose in subjects with normal renal function and subjects on HD.

Methods

Twelve adult males (n = 6 healthy subjects; n = 6 subjects on HD) received single intravenous doses of [14C]difelikefalin containing 100 µCi (total doses of 1.7–3.0 μg/kg difelikefalin). Blood, urine, feces, and dialysate samples (when applicable) were collected after dosing.

Results

The median time to maximum concentration was similar for HD and healthy subjects, occurring at 5 min post-dose. The mean area under the concentration–time curve (AUC) was approximately 11-fold higher in HD versus healthy subjects; mean plasma half-life was 38.0 h and 2.6 h, respectively. In healthy subjects, 80.5% of the dose was recovered in urine, and 11.3% was recovered in feces. In subjects on HD, 58.8% of the dose was recovered in feces, and 19.5% was recovered in dialysate [for subjects on HD with residual kidney function (n = 3), 11.2% was recovered in urine]. Based on plasma AUClast, parent [14C]difelikefalin was the most abundant analyte in systemic circulation (> 99% of total exposure) for both cohorts. Metabolite profiles in urine and feces suggested minimal metabolism of the parent compound.

Conclusion

In subjects on HD, difelikefalin total exposure was higher and plasma half-life was longer compared with subjects with intact renal function. Metabolism was low in both healthy subjects and subjects on HD, with unchanged drug representing > 99% of systemic circulation; however, the route of excretion was primarily into urine versus feces in healthy subjects, and feces versus dialysate in subjects on HD.

Registration

ClinicalTrials.gov NCT03947970.
Appendix
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Literature
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go back to reference Wooldridge TD, Mccafferty K, Schoemig M, Szabolcs Csiky B, Zwiech R, Wen W, et al. Efficacy and safety of difelikefalin for moderate-to-severe CKD–associated pruritus: a global phase 3 study in hemodialysis patients (KALM-2) [abstract FR-OR24]. J Am Soc Nephrol. 2020;31(suppl):22–3. Wooldridge TD, Mccafferty K, Schoemig M, Szabolcs Csiky B, Zwiech R, Wen W, et al. Efficacy and safety of difelikefalin for moderate-to-severe CKD–associated pruritus: a global phase 3 study in hemodialysis patients (KALM-2) [abstract FR-OR24]. J Am Soc Nephrol. 2020;31(suppl):22–3.
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Metadata
Title
Pharmacokinetics, Metabolism, and Excretion of Intravenous [14C]Difelikefalin in Healthy Subjects and Subjects on Hemodialysis
Authors
Jeffrey G. Stark
Patrick K. Noonan
Robert H. Spencer
Sarbani Bhaduri
Stephen J. O’Connor
Frédérique Menzaghi
Publication date
28-06-2023
Publisher
Springer International Publishing
Published in
Clinical Pharmacokinetics / Issue 9/2023
Print ISSN: 0312-5963
Electronic ISSN: 1179-1926
DOI
https://doi.org/10.1007/s40262-023-01262-2

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