Targeted cancer drugs and immunotherapy for hairy cell leukaemia

Targeted cancer drugs work by targeting the differences in cancer cells that help them to grow and survive. Other drugs help the immune system to attack the cancer (immunotherapy). 

Some drugs work in more than one way and actually do both. They target a protein on the leukaemia cells, as well as helping the immune system to recognise the cancer.  

You might have the targeted drug rituximab for hairy cell leukaemia. Or you might have the drug interferon, but this is less common.

When you might have targeted and immunotherapy drugs

Chemotherapy is the main treatment for hairy cell leukaemia.

But if chemotherapy doesn't control the leukaemia or if it comes back after chemotherapy, your doctor might suggest that you have rituximab with chemotherapy.

Doctors don’t often use interferon for hairy cell leukaemia any more. But you might have interferon if:

• you are pregnant or have very low levels of neutrophil blood cells

• you can't have chemotherapy or rituximab

• the leukaemia is no longer responding to chemotherapy or rituximab

Rituximab

Rituximab is a type of targeted drug called a monoclonal antibody. It works by seeking out a protein called CD20 found on normal and leukaemic white blood cells (lymphocytes).

Rituximab sticks to the protein and the immune system can then target the cells and kill them. Normal lymphocytes then grow to replace those that are destroyed.

You might have rituximab, or a biosimilar of rituximab, such as Truxima. A biosimilar is not exactly the same as the original drug. But it is very similar and has undergone strict testing to check they work just as well as the original drug. 

Interferon alpha

Interferon alpha 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 really used much any more to treat hairy cell leukaemia. If you cannot have chemotherapy for some reason, then you may have interferon treatment with the drug peginterferon alfa 2a. 

Other targeted drugs

Targeted drugs are constantly in development. Doctors occasionally use other drugs for hairy cell leukaemia including:

• Vemurafenib
• Dabrafenib
• Trametinib
• Ibrutinib

How you have targeted and immunotherapy drugs for hairy cell leukaemia

You have rituximab through a drip into your bloodstream (infusion) once a week or every 2 weeks. You have the treatment in hospital as an inpatient, or as an outpatient at the cancer day clinic. You usually have rituximab with a chemotherapy drug.

You have interferon as an injection just under the skin (subcutaneously), usually 3 times a week. The treatment usually lasts for about a year but you might have it for longer. A nurse can teach you, or someone who cares for you, how to give these injections at home. 

Into the blood stream

You have this treatment through a drip into your arm. A nurse puts a small tube (a cannula) into one of your veins and connects the drip to it.

You may need a central line. This is a long plastic tube that gives the drugs into a large vein, either in your chest or through a vein in your arm. It stays in while you’re having treatment, which may be for a few months.

Injection under your skin

You usually have injections under the skin (subcutaneous injection) into the stomach, thigh or top of your arm.

You might have stinging or a dull ache for a short time after this type of injection but they don't usually hurt much. The skin in the area may go red and itchy for a while.

Side effects

Everyone is different and the side effects vary from person to person. The side affects you have depended on:

• which drug you have
• whether you have it alone or with other drugs
• the amount of drug you have (the dose)
• your general health

A side effect may get better or worse during your course of treatment. Or more side effects may develop as the treatment goes on. For more information about the side effects of your treatment, go to the individual drug pages.

Research into hairy cell leukaemia

Researchers are looking at:

• new targeted and immunotherapy drugs
• different combinations of these drugs with other treatments