Ethnic comparison of pharmacokinetics of 18F-florbetaben, a PET tracer for beta-amyloid imaging, in healthy Caucasian and Japanese subjects

Abstract

Purpose: 18F-Florbetaben is a positron emission tomography (PET) tracer indicated for imaging cerebral beta-amyloid deposition in adult patients with cognitive impairment who are being evaluated for Alzheimer’s disease and other causes of cognitive decline. The present study examined ethnic comparability of the plasma pharmacokinetics, which is the input to the brain, between Caucasian and Japanese subjects. Methods: Two identical phase I trials were performed in 18 German and 18 Japanese healthy volunteers to evaluate the plasma pharmacokinetics of a single dose of 300 MBq 18F-florbetaben, either of low (≤5 μg, LD) or high (50–55 μg, HD) mass dose. Pharmacokinetic parameters were evaluated based on the total 18F radioactivity measurements in plasma followed by metabolite analysis using radio-HPLC. Results: The pharmacokinetics of 18F-florbetaben was characterized by a rapid elimination from plasma. The dose-normalized areas under the curve of 18F-florbetaben in plasma as an indicator of the input to the brain were comparable between Germans (LD: 0.38 min/l, HD: 0.55 min/l) and Japanese (LD: 0.35 min/l, HD: 0.45 min/l) suggesting ethnic similarity, and the mass dose effect was minimal. A polar metabolite fraction was the main radiolabelled degradation product in plasma and was also similar between the doses and the ethnic groups. Conclusion: Absence of a difference in the pharmacokinetics of 18F-florbetaben in Germans and Japanese has warranted further global development of the PET imaging agent.