A study looking at dactinomycin and vincristine in children and young people with Wilms' tumour (PK 2003 08)

The researchers found that there were variations in the levels of dactinomycin found in the children’s blood. These are results from 2 studies known as PK 2006 07 and PK 2003 08.

Over 100 children and young people up to the age of 21 took part. The researchers collected blood samples from everybody over a period of 8 years and measured the amount of dactinomycin their blood. They also measured the amount of vincristine in a smaller group of children. The medical name for this kind of study is pharmacokinetics .

The researchers took blood samples before the children had dactinomycin, then every few hours after having the drug and a final sample after 26 hours. The study team have the results for over 100 children. When they looked at the level of dactinomycin in the blood, the samples showed that bigger children tended to have lower levels of dactinomycin than smaller children. Currently doctors cap the dose of dactinomycin they give to bigger children over a certain weight. The researchers suggest that bigger children may benefit from a slightly higher dose than the capped dose that they currently have but this needs to be further investigated.

The researchers also took blood samples from a smaller group of children before and every few hours after having vincristine. They concluded that these children had satisfactory levels of vincristine in their blood.

The most common side effects of dactinomycin were

• A high temperature (fever)
• A drop in blood cells causing an increased risk of infection, bleeding problems and tiredness.

The trial team concluded that a slightly higher dose of dactinomycin in bigger children should be looked at further in future clinical trials.

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 ) and published in a medical journal. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.