Antibody imaging as biomarker in early cancer drug development and treatment

Over the last decades many key pathways in cancer were identified, which raised interest in development of targeted drugs including antibodies. This process benefits of reliable companion biomarkers to enrich the patient population that may benefit of these drugs and to determine drug effects already in early stages of drug development. Traditional biomarker analysis relies on tumor biopsies, which cannot always be collected due to limited accessibility and procedural risks. Moreover, biopsies provide only static information while tumor heterogeneity, including intra-patient and intra-tumor heterogeneity are disregarded.
Molecular imaging with positron emission tomography (PET) and antibodies labeled with a radionuclide is a potential complementary molecular analysis technique and biomarker. This allows to noninvasively visualize whole body tumor uptake and biodistribution of (modified) therapeutic antibodies. In this thesis the feasibility of this approach for several antibodies and for different cancer types is shown.
Another potential form of molecular imaging in this setting is optical imaging with a fluorescent labeled antibody. This is of potential interest for intraoperative guidance and to provide detailed insight in drug localization in the tumor.
These findings, when further verified in larger trials, might support prediction of treatment efficacy and guide decision making in early clinical drug development next to use for tumor detection during surgery.