II. B. 9 Recombinant Adenovirus Vectors In Human Gene Therapy Trials. 
Recombinant adenovirues are being employed in gene therapy trials at several institutions. Human 
clinical studies ar underway to determine their efficacy and safety in treating cystic fibrosis. From the 
limited data available at this time, it appears that the vector itself is likely to induce some degree of 
inflammatory response that is independant of the transgene employed. Zabner and colleagues [41] 
observed mild inflammation in the nasal epithelium of patients treated by nasal application of an 
Ad2.CFTR vector. This was thought to be secondary to procedure-related trauma as similar nasal 
epithelial changes were seen in normal volunteers sham treated with saline rather than virus 
containing solutions. Intrabronchial administration of Ad.CFTR has been noted to cause pulmonary 
infiltrates in cystic fibrosis patients receiving greater than 10 9 pfu of virus (unpublished 
observations, Ronald Crystal). These changes are similar to inflammatory lesions induced in non- 
human primates in preclinical toxicity studies. Simon et. al. [42] noted the development of a 
mononuclear cell inflammatory response in baboons who received 10 9 and 10 10 pfu/ml. While not 
clinically apparent, this did result in radiographic changes on chest radiographs that were consistent 
with the alveolar wall damage and intra-alveolar edema [42]. A detailed account of the University of 
Pennsylvania Cystic Fibrosis Gene Therapy protocol is provided in Appendix VI.C, page 27. 
III. Clinical Design 
III. A Summary 
Gene therapy with the transfer of the drug susceptibility gene Herpes virus thymidine kinase (HSV-TK) 
has shown promise in a number of animal models, including CNS tumors. Given the extremely poor 
prognosis of patient with recurrent brain tumors and the development of new gene transfer technology, 
we wish to undertake a study of HSV-TK gene transfer for the treatment of adult patients with glioma. 
This study will evaluate the use of adenovirus-mediated transfer of the HSV-TK gene into primary 
human brain tumors followed by systemic treatment with ganciclovir. The goals of this phase I study is 
to evaluate the overall safety and efficacy of this treatment and to gain insight into the parameters that 
may limit the general applicability of this approach. 
Adult patients with glioma that have recurred despite the standard dose of radiation therapy will be 
considered for treatment if they: 1) present with tumor volumes less than 50 cm 3 by MRI scan, 
(tumors must not be adjacent to the chiasm or brainstem, and must not demonstrate subependymal 
spread), 2) exhibit minimal cerebral edema by MRI scan, and 3) have a performance status of at least 
70% by the Karnofsky scale. Eighteen patients will be entered into one of two phase I trials. Nine 
patients with tumors amenoble to pallioline resection (Phase IA study group), and nine with surgically 
unresectable lesions (Phase IB study group) will be sought (figure 4). Three patients from each group 
will be treated at each of three virus dose levels. The adenovirus will be stereotactically injected into 
multiple sites of the tumor. Two days later, GCV treatments will be initiated (intravenously, twice a 
day). MRI scans will be performed on the day of stereotactic injection, and on days 2, 7, and 28. The day 
2 MRI study will detect any post-procedure bleeding and will serve as a baseline for subsequent studies. 
Minimal procedure induced inflammation is anticipated at this early time point. PET scans will be 
performed preoperatively and on days 14 and 28. Seven days postoperatively, the patients in group IA 
will again be taken to the operating room for tumor debulking. A second injection of virus into the tumor 
bed will be performed introoperatively under direct visualization with a dose of virus equal to the 
patient’s initial dose. GCV will be administered for another 14 days. Histologic and PCR studies will be 
performed on the resected tissue to assess the amount of viable tumor, the presence of transgene 
(HS Wtk) and HS Mtk protein and the degree of lymphocytic infiltration. The patients in the inoperable 
group (phase IB study group) will be treated for a total of 14 days with GCV, and then followed clinically 
and by MRI and PET scans for evidence of tumor response or toxicity. The phase I studies will provide 
information on the systemic toxicity associated with stereotactically and intraoperatively delivered 
recombinant virus expressing thymidine kinase. Additionally, by examining the resected tissue 
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Recombinant DNA Research, Volume 20 
