Biological therapy for hairy cell leukaemia

Biological therapy is treatment with substances that are made naturally in the body or that change the way particular substances work in the body. Doctors use a type of biological therapy called rituximab to treat hairy cell leukaemia. Rarely they may use another biological therapy drug called interferon.

Rituximab is a type of biological therapy called a monoclonal antibody. Rituximab works by seeking out a protein called CD20 found on normal and leukaemic white blood cells (lymphocytes). Once it has found the lymphocytes, it sticks to them and the immune system then targets the cells and kills them. Normal lymphocytes then grow to replace those that are destroyed.

Chemotherapy is the main treatment for hairy cell leukaemia. But if chemotherapy doesn't control the leukaemia or if it comes back after chemotherapy treatment your doctor may suggest that you have rituximab with chemotherapy.

You are most likely to have side effects when you first have rituximab. You may have one or more of the following

• Fever, chills and shivering
• Feeling sick
• An itchy rash
• A headache
• Low blood pressure leading to feeling faint
• Wheezing

You usually have medicines before the rituximab (paracetamol, an antihistamine and a steroid) to try and prevent an allergic reaction and these usually work well. If you do have a reaction, your nurse may slow down your rituximab drip to help control it.

There is detailed information about rituximab and coping with side effects in the cancer drug section.

Interferon is a natural substance that our bodies produce as part of our immune response. Interferon therapy can boost our immune system and help fight cancer. It helps to stop the leukaemia cells growing. Interferon is not commonly used for hairy cell leukaemia but your doctor might prescribe interferon in the following situations.

• You can't have chemotherapy or rituximab
• Your HCL is no longer responding to chemotherapy or rituximab

You have interferon as an injection just under the skin (subcutaneously), usually 3 times a week. The treatment usually lasts for about a year. A nurse can teach you, or someone who cares for you, how to give these injections at home. You have a syringe that comes ready filled, or an injection device that looks like a pen, which makes injecting easier to manage. If you don’t think you can do the injections, your practice nurse or a district nurse can give them instead. The nurse can also give you advice on managing any side effects.

The main side effects of interferon are flu symptoms during the first week or two of treatment, including

• Chills
• Fever
• Headaches
• Backache
• Pain in the joints and muscles

Taking paracetamol half an hour before your injection can help to prevent or reduce these side effects. You should continue to take paracetamol every 6 hours until the side effects wear off. This is usually within 6 to 12 hours of having the injection. Many people prefer to have the injection just before they go to bed. That way, they sleep through the side effects. Interferon can also make you

• Feel sick
• Lose your appetite
• Feel particularly tired

Although these side effects are uncomfortable at the time, they tend to improve as the treatment progresses. Some people find that interferon can make them feel sad or even depressed.

You can find detailed information about interferon treatment and its side effects, in our cancer treatment section.

You can read about the immune system on this website. There is also information about the different types of biological therapies, including monoclonal antibodies in the cancer treatment section.