Histology independent therapies (HITs)
Histology independent therapies (HITs) are a type of cancer treatment called targeted therapy. They target gene changes and treat different cancer types with different drugs.
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What are HITs?
Histology independent therapies (HITs) are a type of cancer treatment called targeted therapy.
Targeted therapy drugs find and attack cancer cells. They target something in or around the cancer cell that is helping it grow and survive.
There are many types of targeted therapy. Different drugs are used to treat different cancer types. Some targeted therapy drugs are only effective if the cancer cell has a certain gene change (see ‘Gene changes’ heading below).
Cancers are usually treated based on where they start in the body. For example, bowel cancer is treated with drugs that work on bowel cancer cells. Even if the bowel cancer cells have spread to other parts of the body, such as the lungs or liver, they are still bowel cancer cells. So you would be given drugs that treat bowel cancer.
Using HITS to treat cancers with a gene change
HITs are different from other targeted therapy drugs. This is because they can treat any type of cancer that has a certain gene change. For example, there is a gene change called the NTRK gene fusion, which can be found in over 20 different types of cancer.
HIT drugs can treat any cancer with this gene change. Doctors will choose HIT drugs based on the gene change, rather than on where in the body the cancer started. If the cancer cells have the NTRK gene fusion, the drugs may be used in adults or children.
Other HIT drugs are being developed that may be effective for cancers that have different gene changes.
To help you understand HITs and gene changes, it is useful to know what genes are and what they do.
Booklets and resources
What are genes?
Our bodies are made up of tiny building blocks called cells. Inside nearly every cell is a set of genes. These are the instructions the cell needs to work properly. Different genes instruct different cells. For example, you have a gene that instructs your eyes about eye colour.
Genes are made up of a chemical called DNA (deoxyribonucleic acid). Your DNA is unique to you.
Genes are organised into structures called chromosomes. Chromosomes are arranged in pairs. They are contained in the centre (nucleus) of nearly every cell in your body.
You can learn more about genes, genomes and DNA at the Genomics Education Programme.
Cells, chromosomes and genes
Gene changes
Cells in your body divide to make new cells all the time. Sometimes when the cell divides, something goes wrong and a gene changes. A change in a gene is called a gene variant or mutation.
If a gene is changed, it may not give the correct instructions any more. Cancer may develop if cells are not working properly because of gene changes. The cells may multiply in an abnormal way and grow out of control.
Different gene variants affect different types of cancer cell. The histology independent therapy (HIT) drugs larotrectinib (Vitrakvi®) and entrectinib (Rozlytrek®) could work on any cancers that have a gene variant called NTRK gene fusion.
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Who are HITs for?
Histology independent therapies (HITs) can treat certain cancers that start in the organs of the body. HITs are not currently used to treat blood cancers such as leukaemia or lymphoma. This is because they are not effective at treating these types of cancer.
You may be offered treatment with a HIT drug if you have a cancer that has a gene change called the NTRK gene fusion.
Testing for a gene change
If your cancer doctor thinks an HIT drug is a possible treatment for you, they will test the cancer cells. This is to check whether you have the NTRK gene change.
Your doctors may be able to test a sample of the tissue they took from the cancer when you were first diagnosed. This is called a biopsy. Sometimes they need to take another sample. They will explain if they need to do this and how they will take the sample.
The NTRK gene fusion has been found in some very rare cancers. It is only found very occasionally in more common cancers. Your cancer doctor can tell you more about this.
HIT drugs
There are currently 2 histology independent therapy (HIT) drugs available. They are both used to treat a number of different types of cancer:
- larotrectinib (Vitrakvi®)
- entrectinib (Rozlytrek®).
They may be used when the cancer has tested positive for the NTRK gene fusion. One of the following will also usually apply:
- the cancer has begun to spread from where it started to the surrounding area (locally advanced cancer)
- the cancer has spread to other parts of the body further away from where it started (metastatic cancer)
- surgery to remove the cancer is likely to cause complications
- other treatment has not worked or is not suitable.
It can help to read this information about HIT drugs alongside information about the type of cancer you have.
Side effects of HITs
Like other cancer treatments, histology independent therapies (HITs) can cause side effects. You may have side effects while you are taking the drugs.
The side effects you have will depend on which drug you are taking. Different drugs cause different side effects. The drugs may also affect different people in different ways. Talk to your cancer doctor, specialist nurse or pharmacist if you have any side effects.
Some side effects are mild and can be easily treated. Other side effects can be harder to manage. But these can often be reduced or controlled in some way. Your doctor, nurse or pharmacist may prescribe drugs to help control them.
Side effects may include:
- An increased risk of infection – this is because the drugs may reduce the number of white blood cells in your blood. Your healthcare team will give you advice about this.
- Feeling sick (nausea) – your doctor can give you anti-sickness drugs to help.
- Constipation – your healthcare team can advise you about how to manage this.
- Feeling tired (fatigue) – try to pace yourself and allow time to rest.
- Effects on the nervous system – the drugs may make you feel dizzy or unsteady. Some people have mood changes, memory problems or feel confused. Contact the hospital straight away if you have any of these effects.
Some cancer treatments may cause long-term side effects. HIT drugs have not been used for as long as some other types of cancer treatment. This means doctors do not know yet what any long-term side effects might be.
Your doctors and nurses will monitor you regularly. You should tell them about any new symptoms or side effects you have.
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Making treatment decisions
You and your cancer doctor will decide together the best treatment for you. There are a few things to consider when you are making a decision about treatment. You might want to think about:
- the aim of the treatment
- how successful the treatment is likely to be
- the possible side effects
- how often you will need to go to the hospital, and for how long.
Treatment can be given for different reasons and the potential benefits will depend on your situation.
People make different choices for different reasons. There is no right or wrong decision. The most important thing to remember is that you are making a decision that is right for you at the time.
Your doctors will not be able to give you any treatment until you have given your consent.
Talking about HITs
Before you go to an appointment, it can help to prepare any questions you would like to ask. You may also find it helpful to do the following:
- Take notes during your appointments so you can read them later.
- Record the conversation so you can listen to it later. You should always ask for permission before recording a conversation.
- Ask your healthcare team for a copy of any letters that have the details of your conversations.
- Ask someone to come with you to your hospital appointments, such as a family member or friend. They can support you by making notes or asking questions.
Questions to ask about HITs
Here are some questions that you may want to ask your cancer doctor or specialist nurse:
- What tests do I need?
- Am I eligible for this treatment? If not, are there other treatments I can have?
- How often will I have this treatment?
- Will I need any other tests before or after treatment?
- What are the possible side effects of this treatment?
- Are there possible long-term effects of this treatment?
- What can I do to support myself?
Your feelings
If you have a rare cancer or are having a new type of treatment, it can be harder to connect with other people in the same situation. You may feel lonely and isolated.
You could ask your cancer doctor or specialist nurse if they know other people in the same situation. They may be able to help you contact someone.
It can also help to:
- talk to family or friends
- join a self-help or support group
- contact a support organisation.
Different things work for different people. You may need to try a few things to find out what is most helpful.
Some people find online support groups or communities helpful. You can use online communities to:
- talk to people in chat rooms
- blog (write) about your experiences
- make friends
- join support groups.
You can share your experiences and talk to other people with cancer on the Macmillan Cancer Support Online Community.
Cancer Research UK also has an online forum called Cancer Chat. Here you can talk to others affected by cancer, share experiences and get support.
You can also call the following organisations for support:
- Macmillan Support Line – call for free on 0808 808 00 00
- Cancer Research UK Nurse Helpline on 0808 800 4040
- Sarcoma UK Support Line on 0808 801 0401 – this is for everyone affected by sarcoma.
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About our information
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.
Reviewer
Strategic Adviser for Treatment, New Medicines and Genomics
Macmillan Cancer Support
Date reviewed
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