Combretastatin for advanced cancer

Combretastatin is an experimental treatment that has been tested in the UK, as well as in other countries. It is also called CA4P. It makes the cells that line the smallest blood vessels (capillaries) swell up. This blocks the blood flow to the cancer. All cancers need a blood supply so that they can get the oxygen and food they need to survive. So if we can block the blood flow to a cancer, we might be able to stop it growing.

Combretastatin will only affect blood vessels that supply cancer cells. Cells lining normal blood vessels contain a protein called actin. This protects the blood vessels from combretastatin. Cells lining blood vessels that supply a cancer don’t have actin.

Combretastatin is sometimes called a vascular targeting agent. Some people class this as a type of anti angiogenic drug. But this isn't entirely accurate. The growth of new blood vessels is called angiogenesis so anti angiogenic drugs stop the growth of new blood vessels rather than blocking the existing blood supply to a cancer.

So far, combretastatin trials have been at a fairly early stage. This includes testing the drug on people with advanced cancers, to find out the best dose to give and about side effects. The next stage is to test the drug in particular types of cancer. This work has started to be done and there are a couple of trials on our clinical trials database that have reported on combretastatin for cancers affecting the ovary, and bowel or pancreas.  

So far, combretastatin has shown some promise in treating ovarian cancer that has become resistant to platinum chemotherapy drugs. This is the type of chemotherapy doctors use most for this type of cancer. About a third of the women taking part had some response to the treatment. This was a very small trial and so much more work needs to be done. But researchers said the results were promising.

The main side effect of combretastatin seems to be high blood pressure. In the ovarian cancer trial, this was controlled with medication.  

To find these trials on our clinical trials database, type 'combretastatin' into the freetext search.  But remember to tick the boxes for closed trials and trials with results, as we are not aware of any UK combretastatin trials that are recruiting patients at the time of writing.