Cancer Treatment with Monoclonal Antibodies
Monoclonal antibody drugs are used to combat various types of cancer. Unfortunately, some monoclonal antibody drugs have severe side effects. But it is also clear that these medications have a bright future because they enhance already existing body defenses, and can be improved dramatically as the new drug-production technologies evolve. There have been many failures (scientists have not had tremendous success in general with regard to cancer treatment), but the prospects are still bright and many scientists are working with mAbs for cancer.
Route of Antibody Administration
MAbs for cancer treatment are usually injected to the bloodstream with a carrier although some clinical studies have involved the use of intraperitoneal administration of mAb where the treatment solution is injected to body cavities. Studies in experimental animals and in humans show that direct cavity injection targets smaller peritoneal tumors more efficiently than intravenous antibody treatment. Larger tumor masses are targeted more efficiently by the intravenous method, leading some researchers to hypothesize that the optimal situation will involve both delivery systems concurrently.
Using antibodies to deliver drugs
Treatment with mAbs often uses them like missiles delivering a warhead. The warhead is the drug intended for the cancerous cell or defective areas of the body; the specitivity of the antibodies makes this a truly targeted treatment. Several toxins have been coupled to mAbs and have been analyzed.
Treatment regimens either involve the induction of antibody by the body or the use of antibodies acting in conjunction with the complement system and/or effector cells (i.e., antibody-directed cell-mediated immunity).
One problem – and it is a big problem – with mABs for cancer treatment is that the antibodies that match the malignant cells tend to not be poisonous to the cell. An antibody molecule might attach to a cell and the cell might go about its cancerous business dividing. Scientists try to build an effective therapy by literally attaching a toxin to the antibody. Such toxins as ricin and diptheria have been tried, as have been radioactive atoms for very precise and up-close radiotherapy. The FDA has approved toxin-laden antibodies for treatment of leukemia.
FDA-approved monoclonal antibodies for cancer treatment
|Alemtuzumab (Campath)||Chronic lymphocytic leukemia|
|Bevacizumab (Avastin)||Breast cancer, colon cancer, lung cancer|
|Cetuximab (Erbitux)||Colon cancer, head and neck cancers|
|Gemtuzumab (Mylotarg)||Acute myelogenous leukemia|
|Ibritumomab (Zevalin)||Non-Hodgkin's lymphoma|
|Panitumumab (Vectibix)||Colon cancer|
|Rituximab (Rituxan)||Non-Hodgkin's lymphoma|
|Tositumomab (Bexxar)||Non-Hodgkin's lymphoma|
|Trastuzumab (Herceptin)||Breast cancer|