On the use of change in tumor size to predict survival in clinical oncology studies: toward a new paradigm to design and evaluate phase II studies.

Drug-independent models that link biomarker response to clinical end points are critical to support early (end of phase II) clinical decisions. In oncology, change in tumor size (a biomarker of drug effect evaluated in phase II) is linked to survival (a phase III end point) in some solid tumors. Change in tumor size can be used as a primary end point in the design and evaluation of phase II studies and in supporting go/no-go decisions and phase III study design.