A Randomized, Multicenter, Open-label, Phase 3 Study to Compare the Efficacy and Safety of Panitumumab and Cetuximab in Subjects with Previously Treated, Wild-type KRAS, Metastatic Colorectal Cancer

In this study, the study medication Panitumumab is evaluated for the treatment
of patients with metastatic colorectal cancer in compare to Cetuximab.
Panitumumab is a manufactured antibody. Antibodies are proteins that can be
found circulating in your blood stream. The growth of metastatic colorectal
cancer may be affected by the interaction of a growth factor known as
*epidermal growth factor* (EGF) with its receptor. Panitumumab is an antibody
directed against the receptor for EGF and has been shown to turn off the
activity of the receptor and to stop the growth of cancer cells in several
laboratory tests. If the same effect is observed in people that receive
panitumumab as a treatment, it is possible that their cancer will improve or
resolve.
Panitumumab (marketed as Vectibix®) has been approved in the United States by
the Food and Drug Administration for the treatment of patients with colorectal
cancer whose tumor contains EGF receptors and whose cancer has worsened while
receiving or after receiving treatment with standard chemotherapy.
Panitumumab has been approved by regulatory agencies in Europe, Canada,
Switzerland, and Australia for the treatment of patients with metastatic
colorectal cancer whose tumor status is wild-type KRAS, contains EGF receptors,
and whose cancer has worsened while receiving or after receiving treatment with
standard chemotherapy.
Even though panitumumab has been approved by regulatory agencies, it is
considered experimental in this study.
Approximately 250 centers will participate in this study from North America,
Europe, Asia, and South America. If needed, sites in other countries may also
participate.
Approximately 1000 subjects will be enrolled.

The purpose of this clinical research study is to compare the effect of
panitumumab to cetuximab (Erbitux®) in treating metastatic colorectal cancer
in patients whose tumor contains the wild-type (unchanged) KRAS gene and who
have previously been treated. This study is also designed to collect more
information about the safety of these two drugs.

The study consists of a screening period, a treatment period, a safety
follow-up visit and a long-term follow-up period.
If you are suitable, the treatment visits will then take place once every week
or bi-weekly., depending on the treatment you receive. These visits will be
continued until your disease progresses, after which a safety follow-up visit
will take place. After completion of the treatment your doctor will continue to
monitor your disease by means of a three-monthly visit (or contact by
telephone), until completion of the entire study (approximately 4 years).

You will be selected at random to receive panitumumab or cetuximab. Your
changes of receiving Panitumumab are the same as your changes of receiving
cetuximab.

• Completion of 3 questionnaires related to overall health
• (previously obtained) tumor tissue for KRAS testing
• Infusion of assigned study drugs (cetuximab/panitumumab 1:1). The infusions
will be given through an IV line. Each infusion will take about 30-120 minutes
or more.

• Review of medical history
• Vital signs (blood pressure, pulse, respiration rate, temperature)
• Physical exam including height, weight, and physical status
• Electrocardiogram (ECG).
• Completion of 3 questionnaires related to overall health
• Review of current symptoms and medications
• (previously obtained) tumor tissue for KRAS testing
• Different blood samples will be collected
• CT or MRI scan of chest, abdomen, and pelvis
• Infusion of assigned study drugs (cetuximab/panitumumab 1:1). The infusions
will be given through an IV line. Each infusion will take about 30-120 minutes
or more.