First-in-human phase 0 imaging studies are also known as microdosing proof-of-concept studies and are designed to speed up the development of promising drugs or imaging agents by establishing very early on whether the drug or agent behaves in human subjects as was expected from preclinical studies. Distinctive features of phase 0 studies include the administration of single subtherapeutic doses of the study drug to typically a small number of subjects to gather preliminary human in vivo data on pharmacokinetics, pharmacodynamics, and the target. They enable go/no-go decisions to be based on relevant human models instead of relying on animal data, which can be unpredictive and vary between species. A phase 0 study gives no data on safety or efficacy to cause any therapeutic effect and less risk to human toxicity (USFDA, CDER Guidance, August 2018).
The recent advancements and the great potential of Theranostics technology has allowed the utilization of radioimmune conjugates for diagnosis and treating various diseases in humans. To this end, the use of radiopharmaceutical drugs in phase 0 human studies and prior to early-phase human clinical trials are poised to become more mainstream and strategic regulatory guidance toward rapid, safer, cheaper, and more informed developmental decision in 2024 and beyond. GBI Biomanufacturing is a U.S.-based CDMO with about 20 years of experience and expertise in the radioimmune conjugate (and bioconjugation) arena.
