Biologic agents
Chemotherapy, however, is not the only treatment option, and the rise of biologic therapy has opened new horizons in the management of multiple diseases, including autoimmune disease and cancers. The basic principle of such treatment is stimulating the immune system to act against cancer cells. This can theoretically be used by administering viruses or bacteria and using them as a stimulant for the immune system, but practically the main method of immunotherapy is through monoclonal antibodies. Monoclonal antibodies are antibodies directed towards a single antigen or protein.
To fully understand how can an antibody help you fight cancer, consider this: your body has an army called the immune system, capable to fight bacteria, viruses and any intruder. However, cancer is smart, and blocks itself from detection hiding in plain sight through mimicking normal cells. Your body can fight cancer but can’t see it clearly. Monoclonal antibodies serve to flag these abnormal cells and let your immune system do the rest. Other monoclonal antibodies directly kill cancer or even stop its replication. The potential of immunotherapy are limitless.
But what do monoclonal antibodies target? The answer is actually simple. While they replicate, cancers maintain a fragment of their mother cell, known as clusters of differentiation or CDs. Those clusters are used for the diagnosis of the type of leukemia, its origin and predict its outcome. Monoclonal antibodies are designed to target certain CDs, making them highly specific. Drugs of this family include rituximab, duvelisib and ibrutinib. Most immunotherapies are used in combination with chemotherapy to achieve best results and can be used as a second-line treatment after chemotherapies fail because, unfortunately, they are much more expensive and less effective than chemotherapy, especially if used alone.
The combination of chemotherapy with immunotherapy may not be tolerated by the elderly, which usually make up most patients of chronic lymphocytic leukemia. Instead, chlorambucil is used with rituximab in fragile patients who can’t tolerate conventional regimens.
Some biologic therapies are termed targeted therapy. Although terms may be interchangeable, the concept is still the same. Targeted therapy aims to target a specific molecule on cancer cells that is not present on normal cells, be it an enzyme, a surface protein or a DNA sequence. Advances in this type of therapy are being made on a daily basis as it promises better result and lesser side effects in comparison to traditional therapies.