First-line Therapy of Stage IV Colorectal Cancer

The monoclonal anti-VEGF antibody bevacizumab has been approved for the treatment of stage IV colorectal cancer. The tyrosine kinase inhibitor imatinib mesylate has been shown to efficiently target PDGF-signalling. Blocking PDGFR-signalling leads to disruption of pericytes from the endothelium and reverses the maturation status thereby enhancing the sensitivity to anti-VEGF therapy.This background forms a rationale for a combined therapeutic PDGF and VEGF inhibition. Since bevacizumab shows best activity when used in combination with chemotherapy, capecitabine and oxaliplatin are included in this protocol. Patients with stage IV colorectal cancer and no prior chemotherapy can enter the study. Patients receive oral imatinib once a day on days 1-21. Oral Capecitabine is given on days 1-14 bid, Oxaliplatin and Bevacizumab are given on day 1. Courses are repeated every 22 days in the absence of disease progression or unacceptable toxicity.