In vivo diagnostics
In vivo diagnostics are agents that are used in living patients or animals ( in vivo ) for the purpose of medical diagnosis .
A well-known example are contrast media , which are used, for example, in x-ray fluoroscopy, computed tomography , magnetic resonance tomography - and in ultrasound examinations . The contrast agent is administered to the patient before or during an examination using an imaging method . Contrast media improve the diagnostic informative value of these imaging procedures.
Legal classification
Unless they are pharmacologically , immunologically or metabolically effective, in vivo diagnostics fall under the definition of Directive 93/42 / EEC on medical devices in EU countries , which also provides for their statutory regulation. Many countries have adopted this classification in their national legislation. Notwithstanding this, physically effective in-vivo diagnostics in Germany are not considered medical devices , but rather pharmaceuticals and are therefore not subject to medical device law .
Risk-benefit ratio
Since in vivo diagnostics are very often used in healthy patients, or the state of health of the patient is often not determined before administration, completely different criteria are relevant for approval than for a drug . If a drug has to be proven to be clearly effective in the clinical studies for the approval applied for, in which - depending on the indication, more or less severe side effects can be tolerated (see: benefit-risk ratio ), then for approval of an indoor Vivo diagnostic agent side effects as good as not tolerated.
Product examples
The in vivo diagnostics include:
- Contrast media in the imaging process
- X-ray , computed tomography (X-ray)
- Magnetic resonance tomography ("nuclear spin")
- Sonography (ultrasound)
- Radioisotopes (such as 2-FDG (fluorodeoxyglucose) or 99m Tc ) for the imaging process
Current developments
A research focus for future in vivo diagnostics is currently in the field of nanotechnology. To improve the imaging process, antibodies or other biomolecules such as oligonucleotides, aptamers, short protein sequences, etc., can be bound to nanoparticles that induce fluorescent, magnetic or acoustic signals.
With the targeted connection of nanoparticulate contrast media to diseased cells, it is hoped to improve early detection, for example in the case of cardiovascular diseases , and in the case of tumors, to specify risk classification and therapy control . The long-term goal is the early detection of diseases at the cellular level.
A number of monoclonal antibodies are already used in in vivo diagnostics. The recognition regions of these antibodies are directed against epitopes and neoepitopes , which are usually associated with certain tumors or inflammatory cells. Currently, all antibodies are labeled with radioisotopes that emit hard gamma rays. The metastable radioisotope 99m Tc is used very often . Various research programs are running in order to be able to carry out this form of diagnosis without ionizing radiation sources, for example by means of magnetic resonance tomography.
- Arcitumomab , is a Fab fragment of a murine monoclonal antibody that recognizes an epitope of the carcinoembryonic antigen (CEA). This protein is particularly strongly synthesized in the embryonic intestinal mucosa and in carcinomas of the gastrointestinal tract . CEA is suitable as a recognition molecule for the representation of metastatic carcinomas.
- Sulesomab , is also a Fab fragment of a murine monoclonal antibody that recognizes an epitope on the surface of granulocytes . It can be used to visualize sources of infection and inflammation, for example in patients with osteomyelitis .
- Votumumab , is a human monoclonal antibody. The antibody was isolated from a human lymphoblastoid cell line that was immortalized by infection with Epstein-Barr virus . The antibody can be used to detect recurrences of colorectal tumors .
- Igovomab , an F (ab ') 2 fragment of a murine monoclonal antibody that recognizes the CA 125 antigen. CA 125 is an oncofetal protein that is expressed in more than 90 percent of ovarian serous adenocarcinomas . Igovomab is used for the immunoscintigraphic detection of recurrences of ovarian adenocarcinoma.
Some of the antibodies listed in the examples are also approved for therapy. This eliminates the traditional distinction between diagnostics and therapy , or there is a clear overlap between the two areas of work. The suitcase word Theranostik was formed as a standing term.
See also
literature
- G. Schäffner, D. Kabelitz: Approved monoclonal antibodies for in vivo diagnostics . In: German Medical Weekly . tape 126 , 2001, p. 819-822 .
Individual evidence
- ↑ Schering AG, accessed on August 1, 2007
- ↑ "[...] which are intended by the manufacturer for use in humans for the following purposes: - detection, prevention, monitoring [...] of diseases; [...] and their intended main effect in or on the human body is not achieved either by pharmacological or immunological means or metabolically, [...] "cf. Directive 93/42 / EEC in the consolidated version of October 11, 2007 , Article 1 Paragraph 2 a)
- ↑ § 2 Paragraph 1 No. 2 b) and Paragraph 3 No. 7 AMG
- ↑ Federal Institute for Drugs and Medical Devices: Medical Devices , accessed on August 1, 2007 ( Memento from September 26, 2007 in the Internet Archive )
- ↑ Innovationsstiftung Schleswig-Holstein: Nanotechnology Development Strategy for Hamburg and Schleswig-Holstein , (September 2004), accessed on August 1, 2007 ( Memento from May 17, 2006 in the Internet Archive )
- ↑ Krüger-Brand HE, Nanotechnology: Many Chances, Unknown Risks , in Deutsches Ärzteblatt , 104/2007, pp. A-548 / B-480 / C-464.
- ↑ CEA-Scan ® (Arcitumomab) 8/99 , accessed on August 2, 2007 ( Memento from September 29, 2007 in the Internet Archive )
- ↑ Pharmazeutische Zeitung: MONOCLONALE ANTIBÖRPER - Targeted therapy with high-tech drugs , accessed on August 1, 2007