The combination of erlotinib and bevacizumab represents an effective therapeutic strategy in NSCLC with the highest response rates ever reported for relapsed NSCLC having been observed recently in a phase II trial. Early differentiation of patients profiting and of patients not profiting from this therapy is of major relevance for further improving this targeted therapy approach and to develop more effective, personalized treatment strategies. We aim at this early identification by the combination of molecular and functional imaging tools (FDG-, FLT-PET, DCE-MRI), molecular marker analyses in tissue and peripheral blood (EGFR- and KRAS mutational status and high throughput mutational profiling in tumor tissue, angiogenesis-associated biomarkers and expression profiling in peripheral blood) and pharmokokinetic analyses. From the combined analyses of these tools we expect a better understanding of the host-drug interaction as a precondition for further improvement of erlotinib-bevacizumab combination therapy in NSCLC