title: Early FDG/PET scanning as a pharmacodynamic marker of anti-EGFR antibody activity in colorectal cancer.
abstract: Panitumumab is an anti-EGF receptor (EGFR) antibody approved for use in treatment of chemotherapy-refractory colorectal cancers lacking K-RAS mutations. Despite overall response rates approximating 10%, no marker predictive of clinical benefit has been identified. We describe a chemotherapy-refractory patient whose clinical condition necessitated rapid identification of an effective agent in whom we used (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomographic scanning 48 hours after an initial dose of panitumumab to document a pharmacodynamic response to the antibody. The initial 46% ± 2.7% drop in SUV(max) of four target lesions correlated with a partial response by Response Evaluation Criteria in Solid Tumors and a >90% drop in serum carcinoembryonic antigen at 8 weeks, indicating that an early decrease in FDG uptake may predict subsequent clinical benefit in response to anti-EGFR antibody therapy in colorectal cancer.
authors.affiliation: Hematology/Oncology and 2Radiology and Nuclear Medicine Services, Richmond Veterans Affairs Medical Center and the Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23249, USA. gkrystal@vcu.edu
authors.forename: Geoffrey W
authors.initials: GW
authors.lastname: Krystal
authors.forename: Erin
authors.initials: E
authors.lastname: Alesi
authors.forename: James L
authors.initials: JL
authors.lastname: Tatum
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D000077544:Panitumumab; D049268:Positron-Emission Tomography; D016896:Treatment Outcome
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D019788:Fluorodeoxyglucose F18; D000077544:Panitumumab