CNS 18 - 38 
SUMMARY STATEMENT (Parent Copy) 
GENE THERAPY IN RECURRENT BRAIN TUMORS 
You/your child has a brain tumor which has come back despite having had 
chemotherapy, radiation or both. The chance for a cure is now highly unlikely using 
conventional approaches such as surgery or other chemotherapy. 
We are asking you/your child to take part in a new and very experimental approach. 
We hope to find out if a special gene (a piece of DNA) can be transferred into brain tumors, 
and if a drug can then be given so that the transferred gene can then be used to help kill the 
tumor. Surgery is used to place mouse cells that make a special mouse virus (one that can 
enter dividing cells but cannot cause disease) into the tumor. This special mouse virus 
carries a gene called thymidine kinase which comes from a human virus. Tumor cells, but 
not normal brain cells, take up the special virus and the new gene it carries. We think any 
cells which carry the new gene will be damaged or killed when you/your child are given an 
antivirus drug called ganciclovir. The mouse cells should also be killed by this drug. 
Because only the mouse cells and you/your childs tumor cells will carry this target, we think 
that normal brain cells will not be hurt by ganciclovir. 
This approach has been used in animals and the results are encouraging. A few 
adults have also been treated in this way and have not been harmed. However, this is the 
first time that this experimental therapy is to be used in children. 
Pretreatment Evaluation 
You/your child will have a spinal tap to check for malignant cells, and magnetic 
resonance images (MRI) (of both the brain and spine) with and without a dye to make the 
picture clearer. A special procedure like MRI . called MR spectroscopy (MRS) will also be 
done at that time if you/your child agree. You/your child will also have blood tests 
including blood counts, liver and kidney function tests and blood chemistries. We will also 
do blood studies for HIV, the virus which causes AIDS. If you/your child are positive, we 
will not be able to give you/your child this treatment. In teenage women having regular 
menses a pregnancy test will be done. If this shows pregnancy, we will not be able to give 
you/your child this treatment. 
TREATMENT 
You/your child will have an operation during which the mouse cells that make the 
special virus are directly injected into the tumor. This operation will be done while you/your 
child is under general anesthesia. The neurosurgeon will guide a needle to the tumor 
location(s) through a hole drilled in the skull. We will use an MRI scanner and a computer 
to guide the injection and to try not to do damage to normal brain. The cells will be slowly 
injected. Several separate injections will be made to place the mouse cells into different 
areas of the tumor. The total number of injections will depend on the size of the tumor. 
Some tumors may require more than one hole in the skull. Following surgery, you/your 
child will be monitored in an intensive care unit. 
You/your child will begin to receive ganciclovir (Cytovene) 7 days after surgery. 
This will be given over 1 hour, twice a day for 14 days. MRI scans will be done several 
times during the following days to weeks to see if the treatment is working. 
All patients will be followed as an outpatient with serial blood tests, MRI scans and 
neurologic examinations done at each visit. At first, you/your child will be seen every two 
weeks for two months and then monthly for 10 months. Visits after the first year will be 
scheduled at 3-6 month intervals until 5 years, and then annually . 
Recombinant DNA Research, Volume 18 
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