A trial looking at the drug GSAO in people with advanced cancer (PH1 109)

The research team found that GSAO didn’t cause too many side effects, and they found safe doses to use.

This trial recruited 34 people with an advanced solid tumour (not a leukaemia or a lymphoma). This included people with bowel cancer, ovarian cancer, womb cancer and lung cancer.

Everyone taking part had GSAO though a drip into a vein 5 days a week, for 2 weeks out of every 3.

The first people taking part had the lowest dose of GSAO. As they didn’t have any serious side effects, the next few people had a higher dose. And so on, until they found the best dose to give. This is called a dose escalation trial.

The trial team found that the most serious side effects were a change in how the liver works, a fast heart beat (tachycardia) and inflammation of the brain (encephalopathy). These side effects were rare, and they went away when treatment stopped.

The most common side effects were

• Tiredness (fatigue)
• Constipation and diarrhoea
• Feeling or being sick
• A drop in red and white blood cells
• Dizziness
• Changes to heart rhythm

The research team looked at a number of things in blood samples they took from people taking part in the trial. They found that

• The amount of GSAO in the blood was low, but it was higher with the higher doses
• GSAO didn’t seem to have an effect on some of the markers in the blood which are used to measure the formation of blood vessels
• GSAO didn’t seem to have an effect on some of the markers in the blood which are used to suggest cancer cells are dying

The research team were able to assess how 19 people’s cancer responded to treatment. They found that the cancer

• Stayed the same in 8 out of 19 people
• Continued to grow in 11 out of 19 people

The research team also used a scan called a DCE-MRI scan to look at how blood flow in cancers changed with different doses of GSAO. They found that the different doses of GSAO didn’t seem to affect the blood flow.

The trial team concluded that they had found the best doses to use. And that GSAO did have some side effects, but it is safe to look at in other trials. At the time this trial was completed, a new treatment based on GSAO (called PENAO) was being developed in Australia.

We have based this summary on information from the team who ran the trial. The information they sent us has been reviewed by independent specialists (peer reviewed ) but may not have been published in a medical journal.  The figures we quote above were provided by the trial team. We have not analysed the data ourselves.