Decorative image

About targeted cancer drugs and immunotherapy

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 have it

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 a rituximab with chemotherapy.

You might have interferon if:

  • you can't have chemotherapy or rituximab
  • the leukaemia is no longer responding to chemotherapy or rituximab
  • you are pregnant or have very low levels of neutrophil blood cells


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.

Diagram showing a monoclonal antibody attached to a cancer cell

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 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 undergo strict testing to check they work just as well as the original drug. 

Side effects

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

  • high temperatures (fever), chills and shivering
  • feeling sick
  • an itchy rash
  • a headache

You might have a steroid and antihistamine to try to prevent some of these side effects.

A few people have wheezing and feel faint because their blood pressure drops. You are most likely to have one or more of these side effects in the first 2 hours after having the drug.

If you do have a reaction, your nurse might slow down your rituximab drip to help control it.


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.

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. 

Side effects

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

  • chills
  • high temperatures (fever)
  • headaches
  • backache
  • pain in the joints and muscles

When you go home

This treatment can be difficult to cope with. Your nurse will give you numbers to call if you have any problems at home.

Tell your doctor or nurse about any problems or side effects you have.