Monoclonal antibody is a relatively new class of drug, and its development is one of the biggest advances in the treatment of non-Hodgkin's lymphoma in recent years. The monoclonal antibody for the treatment of non-Hodgkin's lymphoma is rituximab. Rituximab is effective in the treatment of some of the most common types of non-Hodgkin's lymphoma. It is usually given in combination with chemotherapy, although it is given alone in some circumstances.
In many patients, rituximab increases the effectiveness of other treatments (usually chemotherapy). In follicular lymphoma, it can increase the length of the remission produced by the treatment. In the most common types of aggressive lymphoma, adding rituximab has been shown to increase a patient's chance of cure and to improve survival in comparison with the standard chemotherapy alone.
Importantly, the infusion-related side effects of rituximab generally occur only when the drug is being given and decrease with later doses, and giving it with chemotherapy does not cause any significant increase in the side effects caused by the chemotherapy. Side effects lasting longer than a few minutes or hours are rare. For more detailed information on side effects, please read the patient information leaflet that you can get from your doctor.Mode of action
Dosage and administration
Mode of action
Unlike chemotherapy and radiotherapy, which act in a less specific way, the aim of monoclonal antibody treatment is to destroy the non-Hodgkin's lymphoma cells in a targeted way and to leave other types of cells unharmed.
All cells have protein markers on their surface, known as antigens. Monoclonal antibodies are designed in the laboratory to specifically recognise particular protein markers on the surface of some cancer cells. The monoclonal antibody then 'locks' onto this protein. This either triggers the cell to destroy itself or signals to the body's immune system to attack and kill the cancer cell.
For example, rituximab, the monoclonal antibody that is used in the treatment of non-Hodgkin's lymphoma, recognises a protein marker known as CD20. CD20 is found on the surface of the abnormal B cells that are found in some of the most common types of non-Hodgkin's lymphoma.
When rituximab locks onto CD20 on the surface of a B cell, the cell may be destroyed directly, but also the body's natural defences are alerted. Rituximab effectively targets the lymphoma cells for destruction by the body's immune system, which can now kill the cancer cells.
CD20 is also found on the surface of normal B cells, one of the types of white blood cells that circulate in the body. This means that these normal B cells, too, may be destroyed when rituximab is used. However, the stem cells in the bone marrow that develop into B cells do not have CD20 on their surface.
Stem cells are therefore not destroyed by rituximab and can go on to replenish the body with healthy B cells. Although the number of mature, normal B cells is temporarily reduced by the treatment, they return to previous levels after the treatment.
Dosage and administration
Dosage and administration will vary for each antibody given. For example, rituximab, the monoclonal antibody commonly used in the treatment of NHL, is given intravenously, through a needle inserted into a vein, usually in the arm. It is given as a 'drip', which means that the drug is first injected into a bag of fluid, and the fluid then allowed to drip slowly into the vein using the force of gravity. If monoclonal antibody is being used in combination with chemotherapy, it will usually be given just before the chemotherapy, at the beginning of each treatment cycle.
Before the drip is given, other drugs to prevent some of the side effects of the monoclonal antibody are given - for example, paracetamol to reduce fever and anti-histamines to reduce the chances of an allergic reaction. Even so, the side effects of monoclonal antibodies are usually minor and short-lived and can be easily controlled.
If side effects occur while the drug is being given, the drip can be slowed or even stopped until the side effects pass.
For the first treatment, patients either stay in hospital overnight or spend all day there before going home. Subsequent treatments are likely to be much quicker and usually cause few side effects. Most people can be given these later treatments as outpatients and go home the same day.
Like any medication, monoclonal antibodies can cause side effects. For example, for rituximab, most side effects are minor and short-lived, lasting only during the treatment or for a few hours afterwards. Side effects occur most commonly during the first weekly treatment session, and are usually milder with subsequent doses. This is because there are more lymphoma cells during the first treatment that have to be targeted by the monoclonal antibody and destroyed by the body's immune system.
The most common side effects are fevers, chills and other flu-like symptoms such as muscle aches, headache and tiredness. These usually pass quickly once the treatment session is over. Sometimes, patients have a sudden flushing and feeling of warmth in the face. This sensation is usually very brief.
Some patients experience nausea (feeling sick) or vomiting (being sick). Anti-sickness medications (anti-emetics) are usually very effective at either preventing these symptoms or making them more tolerable.
Sometimes, patients feel some pain in parts of the body where the lymphoma is located. The pain is usually mild and can be relieved by ordinary painkillers.
Rituximab can cause an allergic reaction. Symptoms can include:
Major allergic reactions to rituximab are rare, and patients are monitored throughout the treatment session for these symptoms. Patients should report any of these symptoms as soon as they occur. Often, all that is needed is for the intravenous drip to be slowed down or stopped for a short while until the allergic reaction passes. Patients are usually given anti-histamines before the treatment session to help to avoid or reduce these problems.