Study of Gemcitabine and Erlotinib Plus Sorafenib (GES) in Metastatic Pancreatic Cancer

Until very recently, additional therapies in pancreatic cancer have targeted either the vascular endothelial growth factor (VEGF) or epidermal growth factor (EGF) pathways, a strategy which has shown variable clinical efficacy. This inconsistency is not surprising, given the knowledge that tumors have a certain level of signal redundancy which may limit the effectiveness of any one single-targeted therapy. The dual blockade of the EGF and VEGF pathways takes aim at two of the most active cascades in tumorigenesis. Preliminarily, a phase II study done in pancreatic cancer with gemcitabine, bevacizumab and erlotinib or cetuximab has shown promising results and will most likely proceed to phase III study for definitive efficacy assessment (Kindler et al, 2006). In this study, targeted blockade is carried one step further with the inhibition of the signaling cascade downstream of receptor tyrosine kinases at the level of raf. Given the fact that the majority of pancreatic tumors display constitutive activation of the Ras/Raf/MEK/ERK pathway, it is hoped that the addition of sorafenib to gemcitabine and erlotinib will obtain a more complete blockade of the signal transduction cascade responsible for pancreatic tumor growth and progression.