1 
I 
I 
A. Surgical Procedures 
1. Surgically accessible group: Single lesion. Patients will undergo an MRI-guided 
stereotaxic injection of the HS-tk vector-producer cells into their brain tumor. The 
procedure will be performed under general anesthesia. Multiple injections will be 
performed into the tumor as determined by the size of the tumor. Each injection will be 
done using a volumetric pump over 10-30 minutes duration (based on the injected 
volume). 
Seven days following the procedure, the patient will be taken to the 
operating room and under general anesthesia, a craniotomy will be performed and 
complete tumor removal will be attempted. The lining of the cavity will then be infiltrated 
at multiple sites with the HS-tk vector-producer cells. Ganciclovir will be administered 
starting on the fifth post-operative day for 14 days. 
2. Surgically accessible group: Multiple lesions: Patients with multiple lesions 
(metastases) will be considered candidates for removal of multiple lesions according to 
the surgical feasibility of such procedures. In a selected group with multiple surgically 
accessible lesions, a staged surgical excision may be performed. Tumor transduction 
will be performed in two stages: the first will include stereotaxic injection of the lesions 
with the HS-tk-producer cells. Seven days later, the tumors will be removed via open 
j 
surgery and intra-operative infiltration of the tumor lining will proceed as described in 
A.1 . GCV will be administered as in A.1 . ■! 
3. Surgically inaccessible tumors: Single lesion. Patients assessed as having a 
surgically inaccessible tumor will undergo an MRI-guided stereotaxic injection of the 
HS-tk vector-producer cells into their brain tumor. The procedure will be performed 
under general anesthesia. Multiple injections will be performed into each tumor as will 
be determined by the size of the tumor. Each injection will be done using a volumetric 
pump over 10-30 minutes duration (based on the injected volume). Ganciclovir 
administration will begin on the seventh day after the procedure for 14 days. 
4. Surgically inaccessible: Multiple lesions: Patients harboring multiple surgically 
inaccessible lesions will have up to two stereotaxic injections performed in one single 
session. The number of procedures will be determined by the condition of the patient, 
[808] 
Recombinant DNA Research, Volume 15 
