1. From the Gastrointestinal Oncology Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY; Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, PA; Indiana University Cancer Center and the Walther Cancer Institute, Indianapolis, IN; Imclone Systems Inc, Somerville, NJ; Bristol Myers Squibb Inc, Wallingford, CT; and the Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA