In addition, there is a pharmacokinetic companion protocol which will determine the trough and peak levels of cetuximab in 25 patients enrolled in the study at four to eight centers. A pharmacologic serum sample for the determination of levels of cetuximab will be obtained prior to the initial, fourth and sixth cetuximab infusions and 1 hour following the completion of the initial, fourth and sixth cetuximab infusions in the first course; and prior to and 1 hour post the completion of the first cetuximab infusion of each subsequent course of therapy. A course of therapy is defined as six weekly infusions of cetuximab monotherapy. ImClone will perform the pharmacokinetic analyses.