Can you tell me about olaparib?
Olaparib is a type of biological therapy called a PARP-1 inhibitor. This means it blocks a protein called PARP-1. PARP is short for Poly (ADP-ribose) polymerase. This is an enzyme which helps to repair DNA which is damaged. Cancer cells have damaged DNA and rely on PARP to repair it. So when olaparib stops PARP from repairing DNA damage, the cancer cells die. If the treatment works, the cancer should either stop growing or shrink.
Olaparib is a new drug in development for a number of cancers. Its other names are AZD2281 and KU-0059436. You take it as a tablet. Researchers think that it can help fight cancer by stopping cancer cells from repairing themselves.
All new drugs go through a detailed research process. Research in the laboratory finds out if a potential new drug harms cancer cells in any way. Then researchers look at whether it is safe to give to people, what the dose should be, and which side effects it causes. So far olaparib has been used to treat people with advanced cancer. We need more trials involving many more people to find out how well olaparib really works, and for which cancer types.
Most of the research so far into olaparib has been looking at breast and ovarian cancers which have a faulty gene called the BRCA gene. This gene relies on PARP to keep its DNA healthy. About 5% of breast cancers and 10% of ovarian cancers have a BRCA gene fault. Other cancers that sometimes have a faulty BRCA gene include prostate cancer, bowel cancer and lung cancer.
An international phase 2 trial looked at a group of 54 women with advanced breast cancer, who had already had chemotherapy. Half the women had a lower dose of olaparib and the other half had a higher dose. In the women taking the higher dose, 4 out of 10 of the cancers shrank (40%). Researchers say side effects were generally fairly mild and included tiredness and feeling sick. Another phase 2 trial looked at ovarian cancer. Half the women had a lower dose of olaparib and the other half had a higher dose. In the women taking the higher dose, just over 3 out of 10 of the cancers shrank (30%).
In a European phase 1 trial, doctors treated 60 patients with olaparib, including 22 people with faulty BRCA genes. All the people taking part had advanced cancer. They had already had several standard treatments. In almost half of the patients with BRCA gene faults the tumours shrank with olaparib treatment. In people who did not have the gene fault, the cancers did not shrink or stop growing. The researchers say side effects were generally mild, and included feeling sick, tiredness, taste changes, lowered blood cell levels, and loss of appetite.
The results of these trials are promising, but we still need more trials to confirm how well this treatment works.
There is a trial looking at a new tablet form of AZD2281 compared to AZD2281 capsules for advanced cancers, including breast or ovarian cancer in people with BRCA gene faults.
Doctors and researchers hope that olaparib may also work for some people who do not have a BRCA gene fault. There is research looking at using olaparib for people with other types of cancer. There is a clinical trial called PICLLE looking at how well olaparib works for people with chronic lymphocytic leukaemia or mantle cell lymphoma when other treatment is no longer working. And there is a trial looking at giving olaparib with another drug called temozolomide for people with a type of brain tumour called glioblastoma.
You can find the details of these trials on our clinical trials database. Some of the trials are still recruiting people and others are closed and we are waiting for results.Type in 'olaparib' or 'AZD2281' into the search and your choose your cancer type to find out more.
Olaparib is not widely available in the UK at the moment. It is only available as part of clinical trials. Olaparib is still going through the early stages of research to find out how well it works and to get more information about possible side effects.
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