Arcitumomab is a drug used for diagnosis in cancer medicine. Approximately 95 percent of all colorectal cancers can be diagnosed by intravenous administration of arcitumomab in an imaging procedure. This approach is necessary in part because colorectal cancer is usually very difficult to diagnose in any other way. This is because this type of cancer spreads throughout the body largely free of clear symptoms.
What is arcitumomab?
About 95 percent of colorectal cancers can be diagnosed by intravenous administration of arcitumomab in an imaging procedure. Arcitumomab is a so-called monoclonal antibody, which is used in cancer medicine for diagnostic purposes. This antibody is a color fragment that can be obtained from the bellies of mice. In order to obtain Arcitumomab, the mice are first injected with the digestive enzyme pepsin, which has the task in the human digestive system of processing the proteins ingested through food. Once the peptin is administered, Arcitumomab is obtained in two further intermediate steps. The active ingredient falls under the group of immunoconjugates because the antibody is linked to a second, functional molecule. This is the radioactive isotope technetium, which is assigned to the group of transition metals. The preparation was marketed by the company Immunomedics under the trademark CEA-Scan until 2005.
Pharmacological action
The preparation Arcitumomab can be used to diagnose various types of colorectal cancer with the aid of an imaging procedure. The compound is used in combination with single-photon emission computed tomography as an in vivo diagnostic agent to produce high-resolution images. This makes it possible to localize the tumor and determine whether metastasis has already occurred. However, it is necessary to enrich the agent with the element technetium before intravenous administration, because this element is not present in the agent in its pure form. The radioactive preparation is then diluted with a saline solution and injected. Because the element technetium has a half-life of around six hours, there is sufficient time to evaluate the gamma quanta produced during decay and convert them into images. This provides the treating physicians with a relatively reliable finding of the extent and progress of the cancer, and subsequently allows them to prescribe appropriate therapy for treatment. Single photon emission computed tomography is one of the imaging techniques that can be used to examine a wide variety of metabolic processes within the human body. Thus, the procedure is not only used in the diagnosis of cancerous diseases.
Medical application and use
The preparation has been used exclusively for diagnosis by imaging in cancer medicine. This is possible because the carcinomas in colorectal cancer in particular secrete the carcionoembryonic antigen by pressure on the surface of the cell structures. Therefore, about 95 percent of colorectal carcinomas can be diagnosed with Arcitumomab. The vast majority of these are malignant tumors. Overall, colorectal cancer is the second most common cancer in Germany. On average, about six percent of all adult men and women develop colorectal cancer in the course of their lives. Diagnosis is often difficult because colorectal cancer usually develops from benign intestinal polyps. These are fungus-shaped growths that form on the mucosa in the colon. The polyps can range in size from a few millimeters to several centimeters. Particularly in the case of larger polyps, there is a risk that they will develop into colon cancer, which in the rarest cases manifests itself through further symptoms. The chances of cure for colorectal carcinoma are between 40 and 60 percent, and treatment can be by surgery or chemotherapy. However, the success of the cure depends very much on the stage at which the colorectal cancer is detected. In order to detect the disease in time, health insurance companies in Germany have been covering the costs of a colonoscopy every ten years for insured persons from the age of 55 since 2002, provided that there is no suspicion of colorectal cancer after the first colonoscopy.
Risks and side effects
Side effects resulting from the administration of arcitumomab are not known.