BAY 1075553 PET/CT in the assessment of prostate cancer: Safety, tolerability and biodistribution - Phase I first in human study results

1125 Objectives Animal studies showed increased uptake of 18F-labeled BAY1075553 (2RS,4S)-2-[18F]Fluoro-4-phosphonomethyl-pentanedioicacid) in prostate cancer cells expressing prostate-specific membrane antigen. The aim of this study was to evaluate the safety, tolerability and biodistribution of this novel PET-tracer. Methods 12 prostate cancer patients were included into this study. All patients were clinically monitored from 24 hrs before to 5-8 days after tracer administration including physical examination, ECG, laboratory parameters of different organs and documentation of adverse events. PET acquisition started 30 sec. post i.v. injection of 300 MBq BAY1075553 with dynamic PET images in the pelvic region followed by semi-whole body acquisition. Results Safety data showed no relevant changes in the sequential blood values, ECGs, urine testing or physical examination up to 5 - 8 days after i.v. administration of BAY 1075553. Physiological BAY 1075553 uptake was observed in salivary glands and urinary tract. Intensive tracer accumulation was noticed in the urinary bladder. In general, remarkable tracer uptake was seen in degenerative bone lesions as well as in sclerotic vessels. Liver, pancreas, spleen, gastrointestinal tract and bone marrow showed no noticeable physiological uptake. Conclusions The results of this study showed that PET/CT imaging with BAY1075553 was safe and well tolerated. However, early renal excretion and intensive tracer accumulation in the urinary tract as well as non-specific increased tracer uptake in degenerative bone lesions could be the main limitations when using this radio tracer for staging and re-staging of prostate cancer patients. Details regarding the tumor uptake of BAY1075553 will be described in a separate abstract