The substance will be used as iv injection due to the protein nature of the antibody and, to ensure a fast distribution within the body. The study will be performed as an open clinical trial due to the fact that the applied radiation has to be documented; the use of "placebo" radiation would be unethical.
It is expected, that the new antibody fragment with its radioactive linkage will display an image of the activity distribution of the disease. Due to the fact that only patients with active disease have to be imaged and, to allow for comparison of the activity and the clinical distribution of the disease, this proof of concept study (phase I study) will be performed in patients with active disease. Healthy volunteers could not display an activity pattern of the disease. Furthermore, it seems to be unethical to use volunteers for studies with radioactivity with such a risk/benefit ratio (radiation risks vs. missing chance of display of tissue distribution) in a proof of concept study.
