Monoclonal antibodies are used in medicine as a form of immunotherapy, a therapy aimed at utilizing a person’s immune system response to treat a disease. More specifically, therapeutic monoclonal antibodies are typically used to treat some forms of cancer. Monoclonal antibody therapy can have potentially serious side effects, however, including allergic reactions, low blood pressure, fever, nausea, and respiratory concerns.
The human immune system uses antibodies to detect and neutralize antigens, such as bacteria, viruses, and other disease causing agents. Immune system antibodies are proteins capable of recognizing and attacking various antigens. A targeted form of immunotherapy, therapeutic monoclonal antibodies generally have an affinity for a specific antigen or type of cell. They are typically used to treat certain types of cancer, including non-Hodgkin’s lymphoma and breast cancer. They are also sometimes used in the treatment of autoimmune disorders, such as severe forms of systemic lupus erythematosus.
There are two different categories of monoclonal antibodies, and drugs that belong to each category work in different ways. Some therapeutic monoclonal antibodies like rituximab, act by detecting specific disease-causing antigens in the body and attaching themselves to them. In the case of rituximab, the drug attaches itself to a protein called CD20. This substance is found on all mature B cells in the body — B cells being a type of immune system cell. The patient’s immune system is triggered through this process and proceeds to attack all cells on which the therapeutic monoclonal antibodies are attached.
The second category of monoclonal antibodies includes a range of medications used to treat different types of cancer. Antibodies in this category generally target specific proteins that help malignant cells multiply in the body. The monoclonal antibodies attach to these proteins and block communication between them and cancerous cells. In some cases, this means malignant cells may stop multiplying and in others that cancers may decrease in size as they are starved of their blood and nutrient supplies. Drugs in this category include cetuximab, bevacizumab, and trastuzumab.
The use of medications with a high degree of antigen specificity, like therapeutic monoclonal antibodies, to treat malignancies may offer a degree of protection for cells not involved in the disease process and therefore not targeted by the medications. Like with all drugs, there are a number of side effects associated with monoclonal antibodies and these include low red blood cell counts, low blood pressure, irregular heartbeat, breathing difficulties, and nausea. Monoclonal antibody therapy is typically given via an intravenous infusion. Side effects that can arise during an infusion may be rate related and lowering the speed at which the drug is given may help decrease the strength of infusion reactions.