Monoclonal antibody therapies
Monoclonal antibodies are a type of cancer drug that targets certain proteins in cancer cells. The drug ‘sticks’ to the proteins, which can trigger your body’s immune system to help destroy the cancer cells.
You may hear monoclonal antibodies referred to as ‘immunotherapy’ as they are using your own immune system to kill the cancer cells. When it used alongside chemotherapy, this is often called ‘chemoimmunotherapy’.
Rituximab is a type of monoclonal antibody that is common in treatment for Waldenstrom's macroglobulinaemia and has been in use for over 20 years. Rituximab specifically targets and sticks to a protein called CD20. CD20 is found on most of the abnormal B-cells that cause WM, as well as some healthy cells. It triggers the body to destroy these CD20 cells – both abnormal and healthy. Your body will replace the healthy cells when you have finished treatment.
Rituximab is usually given alongside other drugs as part of a chemotherapy regimen, and has shown to be effective at treating WM. It can be used by itself, but this is only recommended in people who are very frail and whose bodies might not be able to cope with a full chemotherapy regimen.
Rituximab is not given if the level of the abnormal IgM is very high, as occasionally rituximab can cause it to rise further. Although this is temporary it makes the blood much thicker. Therefore, sometimes your doctor will give you rituximab later on, after chemotherapy has brought down your IgM levels.
Rituximab is most commonly given intravenously for patients with Waldenstrom's macroglobulinaemia although it can be given under the skin (subcutaneously) for some other types of lymphoma.
What are the side effects?
Due to rituximab causing a reaction, the first dose is given very slowly. Drugs are given to prevent and treat this reaction.
Usually, this reaction lessens or disappears over time. However, some people cannot tolerate the treatment and it has to be stopped permanently.
Rituximab can increase your risk of getting infections. This is because as well as targeting the abnormal cells in your body, it also targets the healthy B-cells that fight infection. On occasion, the treatment can lower the number of neutrophils – white blood cells that fight infection – in your body, again raising your risk of getting infections.
When it is first given, rituximab can cause a reaction such as:
difficulty in breathing
low blood pressure