Research into hairy cell leukaemia

Researchers are looking at the causes and treatment of hairy cell leukaemia (HCL). 

HCL is rare and so there are fewer trials compared to some types of cancer. Some of the trials mentioned on this page are international. They are not recruiting people from the UK. Some of these trials have now stopped recruiting people. It takes time before the results are available. This is because the trial team follow the patients for a period of time and collect and analyse the results. 

We have included this ongoing research to give examples of the type of research being carried out in HCL.

Go to Cancer Research UK’s clinical trials database if you are looking for a trial in the UK. You need to talk to your specialist if there are any trials that you think you might be able to take part in. 


We don’t know what causes HCL. So doctors want to understand more about how and why it develops.

Researchers have found a genetic change (mutation) in people with HCL. It's called BRAF V600E.  They know that this genetic change is important in the development of HCL. But it is not clear why this change happens.

Identifying this genetic change has provided new treatment options. There are drugs available that target this genetic change. Read more about these treatments below.

Looking for gene changes

Scientists are looking at cell samples from people with conditions like HCL. They are collecting samples of blood, bone marrow, tissue and spit (saliva.) They want to discover more about the causes and possible future treatments.


Researchers are looking at:

  • how to improve current treatments
  • new drugs

Improving current treatments

Researchers are always looking for ways to improve treatment.

Chemotherapy is the main treatment for HCL. Doctors sometimes combine it with a targeted drug called rituximab. Researchers know that several chemotherapy drugs work well for people with HCL. These include:

  • cladribine
  • pentostatin

Some trials are also looking at another chemotherapy drug called bendamustine.

Researchers are looking at these chemotherapy drugs combined with rituximab. There are also studies looking at different ways of giving the drugs. And looking at the timing of treatment.

The researchers want to find out more about the best way to treat people with HCL.

New drugs

Researchers are looking at new targeted and immunotherapy drugs. They are looking at how much of the drug is safe to give (the dose).  And they are finding out more about the side effects.

For example, they are looking at:

  • moxetumomab and rituximab for people whose HCL are come back (relapsed)
  • ibrutinib for people with relapsed HCL 
  • a combination of vemurafenib and obinutuzumab for people who have not yet had any treatment
  • binimetinib
  • encorafenib

Collecting information about people with hairy cell leukaemia

The Hairy Cell Leukemia Foundation is based in the United States. It funds a number of treatment trials for people with HCL. They run a Patient Data Registry that is open to researchers across the world. This registry helps them gather information about as many people as possible with HCL. This should help them understand more about the disease. And understand why treatments may or may not work and more about the side effects.

Last reviewed: 
17 Aug 2021
Next review due: 
16 Aug 2024
  • Cancer Research UK Clinical Trials Database
    Accessed August 2021

    Accessed August 2021

  • New treatment options in hairy cell leukemia with focus on BRAF inhibitors
    B Falini and E Tiacci
    Haematological Oncology, 2019. 37 Supplement, pages 30 to 37

  • Vemurafenib Plus Rituximab in Hairy Cell Leukemia: A Promising Chemotherapy-Free Regimen for Relapsed or Refractory Patients
    E Tiacci and other
    Blood, 2016. Volume 128, issue 22, page 1214

  • Hairy cell leukemia: Update on molecular profiling and therapeutic advances
    M Grever and others
    Blood Reviews, 2014. Volume 28, Issue 5

  • The information on this page is based on literature searches and specialist checking. We used many references and there are too many to list here. Please contact with details of the particular issue you are interested in if you need additional references for this information.



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