Microdosing of protein drugs

Poor pharmacokinetics (PK) can seriously limit clinical utility. Knowing early whether a new compound is likely to have the desired PK profile at therapeutic doses is therefore important. One approach, microdosing, has shown high success with small molecular weight compounds, despite early skepticism. Vlaming et al . report the first, and successful, clinical application of a microdose of a humanized recombinant protein. But what is the likely success for this class of drugs more generally?