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PARP inhibitors

PARP inhibitors are a type of targeted cancer drug. They are a treatment for some women with ovarian cancer. They are also in trials as a treatment for other types of cancer.

How they work

PARP is a protein found in our cells, it stands for poly-ADP ribose polymerase. It helps damaged cells to repair themselves.

As a cancer treatment, PARP inhibitors stop the PARP from doing its repair work in cancer cells and the cell dies.

Researchers first looked at these drugs in cancers that already had problems repairing cell damage. They focused on cancers with a change (or fault) in genes called BRCA.

Normally, BRCA1 and BRCA2 genes play a part in cell repair in the body. Cells are less likely to repair themselves if there is a fault in one or both of these genes. People who have faulty BRCA genes have an increased risk of certain cancers including:

  • breast cancer
  • ovarian cancer
  • prostate cancer

Cancer cells with BRCA gene faults already have a poor repair system. So blocking PARP with a PARP inhibitor drug means that the cells are not able to repair themselves and they die.

When you might have PARP inhibitors

PARP inhibitors are a treatment for some women who have a fault in one of the BRCA genes and one of the following types of cancer:

  • ovarian cancer
  • fallopian tube cancer
  • peritoneal cancer

Researchers think that they might work in cancers that have weaknesses in the cell similar to the BRCA gene fault. There are trials trying to find whether they are useful in other types of cancer. And trials trying to find out if they work in ovarian and breast cancers that do not have the BRCA gene fault. 

In some of these trials you have a PARP inhibitor on its own. Or you might have it in combination with other treatments, such as chemotherapy and radiotherapy.  

How you have them

You usually take PARP inhibitors as tablets or capsules once or twice a day. How often you have them and how long you have treatment will depend on:

  • which drug you have
  • the type of cancer you have

Types of PARP inhibitors

Olaparib (also called Lynparza) is a type of PARP inhibitor for some women with one of the following types of cancer:

  • ovarian cancer
  • fallopian tube cancer
  • peritoneal cancer

Your doctor might suggest olaparib if you have one of these cancers and all of the following:

  • you have a change (fault) in the BRCA1 or BRCA2 gene (BRCA positive cancer)
  • a group of chemotherapy drugs called platinum drugs (such as cisplatin or carboplatin) have worked for your cancer in the past
  • you have had at least 3 courses of platinum drugs

Researchers are also looking at olaparib in trials for other types of cancer, including:

  • lung cancer
  • pancreatic cancer
  • head and neck cancer
  • a type of brain tumour called glioblastoma multiforme
  • prostate cancer
  • cancer of the foodpipe (oesophagus)

Other PARP inhibitors in clinical trials include:

  • rucaparib
  • veliparib
  • niraparib

Side effects

All treatments can cause side effects. While there are general side effects for a type of treatment, they vary for each individual drug.

Tell your doctor or nurse if you have any of these side effects. You might be able to have medicines to help control them.

Common side effects of PARP inhibitors include:

  • an increased risk of infection, bleeding problems, tiredness and breathlessness due to a drop in the number of blood cells
  • feeling or being sick
  • tiredness
  • diarrhoea
  • indigestion and taste changes
  • headaches and dizziness
  • changes to the way your liver and kidneys works – you have regular blood tests to check for this

For more information about the side effects of your treatment, go to the individual drug pages.

Information and help

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