Panitumumab and Bortezomib for Patients With Advanced Colorectal Cancer

This study is for patients with colon cancer that cannot be fully removed by surgery and has come back after or not responded to standard chemotherapy treatment. Subjects will be enrolled to either the first part of the study (Phase I) or the second part of the study (Phase II). Phase I will be completed before Phase II will start. The purpose of the Phase I part is to find the highest dose of bortezomib that can be given with panitumumab without causing severe side effects. The purpose of the Phase II part is to test the effects the two drugs have on subjects with colorectal cancer. Panitumumab is a drug that targets a protein important for the growth of cancer cells known as EGFR. By blocking the activity of the protein, panitumumab can block cancer cell growth and even lead to their death. Panitumumab is given intravenously once every two weeks. Panitumumab is approved by the FDA for patients with colorectal cancer. Bortezomib is a drug that targets a part of the cancer cell known as the proteosome. By inhibiting the proteosome, bortezomib can inhibit cancer cell growth and even lead to their death. Bortezomib is given intravenously, once a week, 3 out of every 4 weeks. Bortezomib is not FDA approved for the treatment of colorectal cancer. As part of this study the investigators will be taking biopsies of patients' tumors before any treatment, after starting with the panitumumab alone, and after receiving both the panitumumab and bortezomib. The investigators want to investigate what markers inside tumors may relate to how well these two medications work. These biopsies are required as part of the study.