Surgically accessible lesions will then be debulked (7 days after stereotaxic 
injection), and the tumor bed will be infiltrated with the HS-tk vector producer cells. The 
removed tumor will be evaluated for the efficiency of transduction. GCV will be 
administered beginning on the fifth postoperative day at 5mg/kg/dose BID for 14 days. 
The surgically inaccessible lesions will receive an MRI-guided stereotaxic 
intra-tumoral injection of the retroviral HS-tk vector-producer cells. 7 days later, the 
patients will undergo intravenous therapy with GCV at 5mg/kg/dose BID for 14 days. 
Patients who will exhibit a partial response to therapy will be considered for 
repeated treatments (cell injection and GCV administration) based on their clinical 
status, antibody production to PA317 cells, and the radiographical evaluation of their 
tumors. 
Preliminary Phase: The first stage of the study will be limited to treatment of 3 patients 
with recurrent malignant brain tumors who are considered to have an especially poor 
prognosis with a very short life expectancy (less than 2-3 months). These patients will 
undergo treatment according to the study design proposal and will be particularly 
observed for the development of a significant toxicity which is unresponsive to available 
therapeutic measures. If such a toxicity is not observed, the study will continue to 
include the study population described. 
- Qb je.cilye.s 
1. To determine if intratumoral delivery of a vector-producer cell line into human brain 
tumors will result in in vivo transduction of the brain tumor. 
2. To determine if ganciclovir administration to the HS-tk-transduced tumor will result in 
eradication of the tumor. 
3. To evaluate the short and long term consequences of the implantation of xenogeneic 
vector-producing cells. 
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Recombinant DNA Research, Volume 15 
