A trial looking at AT9283 for children and young people with solid tumours

The researchers found the best dose of AT9283 to give to children and young people with solid tumours.

This was a phase 1 trial. 33 children and young people took part and everyone had at least one dose of AT9283.

The first few children and young people taking part in this trial had the lowest dose of AT9283. The next few people taking part had a higher dose. And so on, until the trial team found the best dose to give. This is called ‘dose escalation’.

The children and young people were put into 6 groups. Each group had a higher dose of AT9283 than the group before.

• group 1 (6 children and young people) had the lowest dose of AT9283
• group 6 (2 children and young people) had the highest dose of AT9283

The children and young people had AT9283 through their central line into a vein for 72 hours (3 days), once every 3 weeks. 

Each 3 week period was one cycle of treatment.

They had up to 6 cycles if they remained well enough for treatment and didn’t have any serious side effects. Then if tests showed that the treatment was working well they were able to have more than 6 cycles while they were still on the trial. 

2 children and young people had 6 cycles. One child or young person had more than 6 cycles of AT9283. And they are still receiving AT9283.

The researchers were able to look at scan and test results of 22 children or young people at different points during the trial. 8 of them had a time where their cancer did not get better or worse (doctors call this stable disease). For 3 this was for 4 or more cycles of treatment.

Overall

• 27 children and young people stopped the trial early because their cancer had started to grow again. So they did not have any further treatment with AT9283.
• 2 stopped the trial early because of bad side effects. 
• Of the 33 children and young people who took part 8 died during the trial. 3 died during treatment with AT9283 and the other 5 died within 28 days of their last dose of AT9283.

The trial team looked at the side effects of AT9283. The most common side effects included:

• a drop in blood cells causing an increased risk of infection, bleeding problems, tiredness and breathlessness
• pain – this includes headaches, pain in the tummy (abdomen) and pain in the arms or legs
• feeling or being sick
• tiredness (fatigue)

The research team found the best dose to give children and young people. This was not the highest dose AT9283 given to group 6, but a slightly lower dose given to group 5. The researchers also concluded AT9283 was safe to use for this group of children and young people. 

They also learned more about what happens to AT9283 in the body (pharmacokinetics ) and how it works in the body (pharmacodynamics ).

The researchers suggest further trials looking at AT9283, possibly in combination with different treatments.