A trial looking at pazopanib and fosbretabulin for ovarian cancer that has come back (PAZOFOS)

Cancer type:

Ovarian cancer




Phase 1/2

This trial is looking at using pazopanib and fosbretabulin together for women with ovarian cancer that has come back. It is for women who have

These cancers are treated in a similar way. When we use the term ovarian cancer in this summary, we are referring to all 3. This trial is supported by Cancer Research UK.

Doctors usually treat ovarian cancer with surgery and chemotherapy.  If the cancer comes back it is possible to have more chemotherapy, but sometimes this stops working.  Doctors are trying to find new ways to treat women in this situation.

Pazopanib is already used to treat some types of cancer.  It is a type of biological therapy. It is a cancer growth blocker. It stops cancer cells forming blood vessels that they need in order to grow.

Fosbretabulin is also called CA4P, combretastatin or Zybrestat.  It is also a biological therapy that targets the blood vessels, but it works in a different way.

Fosbretabulin is quite good at destroying the new blood vessels that form in the centre of a cancer.  But it does not work so well on the more established blood vessels on the outside, so the cancer continues to grow. Researchers think that these 2 drugs may work well together because pazopanib destroys the blood vessels that fosbretabulin cannot reach.

The aims of this trial are to

  • Find the highest safe dose of pazopanib and fosbretabulin when the 2 drugs are given together
  • Learn more about the side effects
  • See whether pazopanib and fosbretabulin together work better than pazopanib alone

Who can enter

You may be able to join this trial if you have one of the following

As well as the above, all the following must apply

  • Your cancer came back or got worse during treatment or within 3 to 12 months of finishing platinum chemotherapy Open a glossary item (this does not need to be your most recent cancer treatment before you join this trial)
  • You have at least one area of cancer that can be measured on a scan or your CA125 levels show that your cancer has continued to grow
  • You have satisfactory blood and urine test results
  • You are well enough to carry out your normal activities, apart from heavy physical work (performance status 0, or 1)
  • You are willing to use reliable contraception for 4 weeks before treatment, during treatment and for 6 months afterwards if there is any chance that you could become pregnant

You cannot join this trial if any of these apply. You

  • Have cancer that has spread to your brain or spinal cord (central nervous system Open a glossary item) and this hasn’t been treated or is causing symptoms. You can take part if you have had treatment, it is not getting worse and you have not had steroids or drugs to prevent fits in the last 6 weeks
  • Have cancer that has spread to your lungs
  • Have had radiotherapy, surgery, biological therapy or hormone therapy or treatment in a trial in the last 4 weeks
  • Have not recovered full from major chest or abdominal surgery
  • Have had the chemotherapy drug mitomycin C or any drug belonging to a group of chemotherapy drugs called nitrosoureas Open a glossary item in the last 6 weeks
  • Have had treatment with a drug called bevacizumab in the last 6 months
  • Are still having side effects from any anti cancer treatment, apart from hair loss, mild or moderate nerve problems as a result of treatment with paclitaxel and some other mild side effects (the trial team can explain this to you more)
  • Have any other medical condition that the trial doctor thinks could affect your taking part
  • Are known to be HIV, hepatitis B or hepatitis C positive
  • Have already had treatment with pazopanib or fosbretabulin
  • Are allergic to the drugs used in this trial, anything they contain, or to similar drugs
  • Have had another type of cancer in the last 2 years, apart from carcinoma in situ of the cervix or non melanoma skin cancer

Trial design

This phase 1/2 trial is in two parts. The researchers need between 9 and 18 people to join the first part of the trial and 110 to join the second part.

In the first part of the trial, the researchers are trying to find the highest safest dose of both drugs when given together.

The first few patients taking part will have a low dose of pazopanib and fosbretabulin. If they don’t have any serious side effects, the next few patients will have a higher dose. And so on, until they find the best dose to give. This is called a dose escalation study. The most suitable dose of each drug will be the dose used in the second part of the trial.

You have fosbretabulin through a drip into a vein once a week for 3 weeks out of 4. This takes about 10 minutes. You have pazopanib tablets once a day every day. If you have bad side effects, the trial doctor may reduce the dose of your drugs.

You have treatment with pazopanib and fosbretabulin for 6 months. As long as you don't have bad side effects, you can carry on with treatment for as long as it is helping you.

In the 2nd part of the trial, the researchers want to compare pazopanib and fosbretabulin treatment with pazopanib alone. This part is randomised. The people taking part are put into 2 different treatment groups by a computer. Neither you nor your doctor will be able to decide which group you are in.

Half the women taking part have pazopanib and fosbretabulin. The other half have pazopanib on its own.

PAZOFOS trial diagram

You have fosbretabulin through a drip into a vein and you have pazopanib as tablets as explained in part 1.  You have treatment in either group for as long as it is helping you.

After 6 months, if you are still benefitting from treatment, you can continue treatment for as long as it is helping you.

Hospital visits

You will see the doctors and have some tests before you start treatment. The tests include

  • Blood tests
  • Physical examination
  • Heart trace (ECG Open a glossary item)
  • CT scan of you cancer

You may also have a test to measure how well your kidneys are working. This is called a glomerular filtration rate test (GFR test) Open a glossary item.

During your treatment on this trial you go to hospital once a week nearly every week. Sometimes you may only need to go every week for 3 weeks, with no hospital visit on the 4th week. At these visits, you see a doctor and have regular blood tests and ECGs.

You have fosbretabulin treatment as an out patient and you pick up your pazopanib tablets every 4 weeks.

You have a CT scan every 2 months for 6 months to find out whether the treatment is working. You can continue treatment as long as your cancer has shrunk or stayed the same.

After 6 months, and while you continue pazopanib treatment, you go to hospital every 4 weeks. A doctor will check how you are and you have further blood tests. You have a CT scan every 3 months.

You have a final hospital appointment as part of this trial about 4 weeks after your last dose of pazopanib or pazopanib and fosbretabulin. You see a doctor, have blood tests and you may have a CT scan.

Side effects

Fosbretabulin is quite a new drug so there may be side effects that we don't know about yet. Possible side effects include

The most common side effects of pazopanib include

  • Loss of appetite
  • Taste changes or loss of taste
  • Headaches
  • Raised blood pressure (hypertension) – you can have treatment to lower this
  • Diarrhoea
  • Feeling or being sick
  • Stomach pain
  • Hair colour changes, Hair loss or thinning
  • An effect on the liver which is unlikely to cause symptoms, and usually goes back to normal after the treatment ends – you will have regular blood tests to check how your liver is working
  • Tiredness (fatigue)
  • Skin rash
  • Hand foot syndrome – soreness and redness of the palms of the hands and soles of the feet

We have more information about pazopanib.



Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Professor Gordon Jayson
Professor Gordon Rustin

Supported by

Cancer Research UK
Cancer Treatment and Research Trust (Mount Vernon Cancer Research)
The Christie NHS Foundation Trust

Other information

This is Cancer Research UK trial number CRUKE/13/022.

Questions about cancer? Contact our information nurses

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Around 1 in 5 people take part in clinical trials

3 phases of trials

Around 1 in 5 people diagnosed with cancer in the UK take part in a clinical trial.

Last reviewed:

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