Plasma pharmacokinetics, whole-body distribution, metabolism, and radiation dosimetry of 68Ga bombesin antagonist BAY 86-7548 in healthy men.

UNLABELLED:This first-in-human study investigated the safety, tolerability, metabolism, pharmacokinetics, biodistribution, and radiation dosimetry of (68)Ga-bombesin antagonist (68)Ga-DOTA-4-amino-1-carboxymethylpiperidine-d-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 (BAY 86-7548). METHODS:Five healthy men underwent dynamic whole-body PET/CT after an intravenous injection of BAY 86-7548 (138 ± 5 MBq). Besides total radioactivity, plasma samples were analyzed by radio-high-performance liquid chromatography for metabolism of the tracer. Dosimetry was calculated using the OLINDA/EXM software. RESULTS:Three radioactive plasma metabolites were detected. The proportion of unchanged BAY 86-7548 decreased from 92% ± 9% at 1 min after injection to 19% ± 2% at 65 min. The organs with the highest absorbed doses were the urinary bladder wall (0.62 mSv/MBq) and the pancreas (0.51 mSv/MBq). The mean effective dose was 0.051 mSv/MBq. BAY 86-7548 was well tolerated by all subjects. CONCLUSION:Intravenously injected BAY 86-7548 is safe, and rapid metabolism is demonstrated. A 150-MBq injection of BAY 86-7548 results in an effective dose of 7.7 mSv, which could be reduced to 5.7 mSv with frequent bladder voids.