title: Safety and efficacy of arcitumomab imaging in colorectal cancer after repeated administration.
abstract: In pivotal phase III clinical trials for detecting recurrent or metastatic colorectal cancer, most patients received a single arcitumomab injection. However, the early detection of postsurgical recurrence or metastases with arcitumomab will necessitate serial studies for surveillance. We present immunogenicity, safety, and imaging data supporting the use of multiple administrations of arcitumomab.
  
  
  METHODS
  Human antimouse antibody (HAMA) response, adverse events, clinical laboratory values, and diagnostic imaging results were evaluated in 44 patients (24 men, 20 women; age range, 2878 y) after repeated arcitumomab administration (44 second and 3 third injections). Most patients initially had Dukes' class B or C colorectal cancer and had known or occult disease recurrence and elevated serum carcinoembryonic antigen levels at the time of the repeated injection.
  
  
  RESULTS
  At the repeated injection, in no patient did elevated HAMA titers develop, hematology and serum chemistry changes were clinically insignificant, and only 1 adverse event (eosinophilia) was judged at least possibly related to arcitumomab. Arcitumomab imaging results at the second injection were comparable with those obtained in phase III trials after a single injection of arcitumomab, having a 78% per-lesion concordance with CT in the abdomen and pelvis and a 73% sensitivity and 94% specificity based on 9 patients with cancer confirmed surgically at 11 anatomic sites and excluded at 16 sites.
  
  
  CONCLUSIONS
  These data indicate that at least 2 injections of arcitumomab can be given safely to patients with colorectal cancer, without increased immunogenicity and with imaging efficacy equivalent to the first administration.
authors.affiliation: Department of Clinical Research, Immunomedics, Inc, Morris Plains, New Jersey 07950, USA.
authors.forename: W A
authors.initials: WA
authors.lastname: Wegener
authors.forename: N
authors.initials: N
authors.lastname: Petrelli
authors.forename: A
authors.initials: A
authors.lastname: Serafini
authors.forename: D M
authors.initials: DM
authors.lastname: Goldenberg
mesh_terms: D000230:Adenocarcinoma / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D000818:Animals; D000910:Antibodies, Heterophile / Q000097:blood; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000009:adverse effects; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000008:administration & dosage / Q000009:adverse effects; D016719:Radioimmunodetection; D012680:Sensitivity and Specificity; D013667:Technetium; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D000910:Antibodies, Heterophile; D000911:Antibodies, Monoclonal; D015609:Organotechnetium Compounds; C114976:technetium Tc-99m arcitumomab; D013667:Technetium