[¹⁸F]PTV-F1 PET for OATP Transporter Imaging of the Liver. -Preclinical and Phase I Clinical Study-

Objectives [¹⁸F]PTV-F1 is a potential tracer for the quantitative evaluation of OATP transporter of the liver. The aim of this study was to assess the feasibility of [¹⁸F]PTV-F1 PET imaging using rats and to assess the phase I clinical PET imaging using healthy volunteers.

Methods For preclinical in-vivo study, [¹⁸F]PTV-F1 PET imaging was conducted using rats. For human study, under the approval of institutional ethical committee, the clinical trial study was conducted with healthy volunteers. All subjects were injected [¹⁸F]PTV-F1 and dynamic PET were acquired, followed by whole body static scans were performed using PET/CT camera.

Results In animal study, [¹⁸F]PTV-F1 rapidly accumulated into the liver then eliminated to the bile, while the uptake of the radiotracer in the liver was significantly inhibited by pretreatment with rifampicin. Clearance of the radiotracer from the liver was 11.0+/-2.08 mL/min/kg, while 2.04+/-0.15 with rifampicin calculated by integration plotting using PET data. In-vivo merabolical stability of [¹⁸F]PTV-F1 was also revealed by radio-TLC analysis. In human dynamic PET imaging demonstrated that the hepatobiliary systems were the principal pathways of clearance of [¹⁸F]PTV-F1. The SUVmean values in the liver reached as 30-40 at 15-20 min after injection. Analysis of radiation dosimetry to assess the radiation exposure due to this PET imaging using OLINDA/EXM 1.1 showed 0.0121 mSv/MBq as the effective dose for the adult model. Also, no adverse event was reported in this phase I study.

Conclusions The biodistribution, radiation dosimetry characteristics and lack of adverse event of [¹⁸F]PTV-F1 determined in phase I clinical study indicated that PET with [¹⁸F]PTV-F1 PET would be suitable and promising imaging for OATP transporter.