CNS 18 - 35 
SUMMARY STATEMENT (Chart 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 . 
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Recombinant DNA Research, Volume 18 
