Technetium (99mTc) arcitumomab is an immunoconjugate. Arcitumomab is a Fab' fragment of IMMU-4, a murineIgG1 monoclonal antibody extracted from the ascites of mice. The enzyme pepsin cleaves the F(ab')2 fragment off the antibody. From this, the Fab' fragment is prepared by mild reduction.
Before application, arcitumomab is reconstituted with a solution of the radioactive agent sodium pertechnetate (99mTc) from a technetium generator.[1]
Technetium (99mTc) arcitumomab is contraindicated for patients with known allergies or hypersensitivity to mouse proteins, as well as during pregnancy. Women should pause breast feeding for 24 hours after application of the drug.[1]
Adverse effects and overdose
Only mild and transient side effects have been observed, mostly immunological reactions like eosinophilia, itching and fever. Some patients develop human anti-mouse antibodies, so there is the theoretical possibility of anaphylactic reactions. High doses of IMMU-4 (up to 20-fold diagnostic arcitumomab dose) have not led to any serious events. One patient has been reported to develop a grand mal after application.[1]
Radioactivity can lead to radiation poisoning. Since the dose of an arcitumomab application is about 10 mSv,[1] such an overdose is unlikely.
^Behr T, Becker W, Hannappel E, Goldenberg DM, Wolf F (December 1995). "Targeting of liver metastases of colorectal cancer with IgG, F(ab')2, and Fab' anti-carcinoembryonic antigen antibodies labeled with 99mTc: the role of metabolism and kinetics". Cancer Research. 55 (23 Suppl): 5777s–5785s. PMID7493346.
Further reading
Primus FJ, Newell KD, Blue A, Goldenberg DM (February 1983). "Immunological heterogeneity of carcinoembryonic antigen: antigenic determinants on carcinoembryonic antigen distinguished by monoclonal antibodies". Cancer Research. 43 (2): 686–92. PMID6184152.
Hansen HJ, Jones AL, Sharkey RM, Grebenau R, Blazejewski N, Kunz A, et al. (February 1990). "Preclinical evaluation of an "instant" 99mTc-labeling kit for antibody imaging". Cancer Research. 50 (3 Suppl): 794s–798s. PMID2297726.
Hughes K (1995). "Use of radioimmunodetection with CEAScan in planning for resection of recurrent colorectal cancer". Proc Amer Soc Clin Oncol. 14: 544.
Moffat FL, Pinsky CM, Hammershaimb L, Petrelli NJ, Patt YZ, Whaley FS, Goldenberg DM (August 1996). "Clinical utility of external immunoscintigraphy with the IMMU-4 technetium-99m Fab' antibody fragment in patients undergoing surgery for carcinoma of the colon and rectum: results of a pivotal, phase III trial. The Immunomedics Study Group". Journal of Clinical Oncology. 14 (8): 2295–305. doi:10.1200/JCO.1996.14.8.2295. PMID8708720.