CNS 18 - 41 
ASSENT FORM: GENE THERAPY FOR RECURRENT PEDIATRIC BRAIN TUMORS 
You have a brain tumor that has not gotten better with standard treatment. We would like you 
to be in a study of a very new type of treatment called gene therapy. For this treatment, a 
special virus will be used to carry a "target gene" (a piece of DNA) into the tumor cells. Tumor 
cells with the target gene should die when they come in contact with an anti-virus drug called 
"ganciclovir." Because the gene should only go into the tumor cells, normal brain cells should 
not be hurt. This treatment has been done in some adults with brain tumors, but this is the first 
study in children. 
We will need to do several tests before the treatment is given. We need to check for tumor cells 
in the spinal fluid (spinal tap) and test for HIV (the virus that causes AIDS). If these tests are 
positive, gene therapy can’t be used. Also, pregnant patients can’t have this treatment. 
TREATMENT: 
An operation will be done to put the special gene into the tumor cells. While you are asleep 
(general anesthesia), the neurosurgeon will guide a needle to the tumor through a small hole 
drilled in the skull. The cells with the target gene will be injected into the tumor. This may 
be done in more than one place if the tumor is large. Seven days later you will begin to get the 
ganciclovir. It will be given by vein (IV) twice a day for 14 days. You will be in the hospital 
for the treatment. We will do MRI scans several times after treatment to see if the tumor is 
getting smaller. You will need to be seen often in the clinic after the treatment for scans and 
blood tests. 
RISKS AND SIDE EFFECTS 
The operation to put the target gene in the tumor can cause severe bleeding, worsening of 
strength or feeling, and problems talking and remembering things. There is also risk of 
infection. The neurosurgeon will talk to you about the chances of these bad effects. 
The special virus that carries the gene has been used in many patients before and has not caused 
problems. There is a very small chance that the virus could cause infection, but we don’t think 
this will happen. If the target gene gets into normal brain cells, those cells could be killed too. 
We do not think this will happen, but we can’t be sure. 
Gancyclovir has been used to treat viral infections in many people. Its main bad effect is low 
blood counts, which can lead to infection and bleeding. We will stop the drug if counts go too 
low. 
Because this therapy is so new, there may be other bad effects that we do not yet know about. 
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