To begin to evaluate this question, cotton rats were administered AvlCFl 
(intratracheal 10 9 pfu/kg) . Ten days later, the animals were challenged 
with the same dose of intratracheal AvlCFl, and 4 days later the animals 
were sacrificed (AvlCFl followed by AvlCFl n-*8 ; vehicle followed by vehicle 
n-8) CRCC.002. No deaths were observed. The morphology of the lungs in the 
AvlCFl/AvlCFl group showed a mononuclear cell inflammatory response, but 
somewhat milder than that of the animals evaluated at the beginning of the 
challenge period (i.e., 10 days after a single administration of AvlCFl, 
see Section 4.4). The animals receiving the vehicle had no inflammation. 
These studies suggest that the intratracheal challenge with the vector 
would not result in an adverse reaction with severe acute clinical conse- 
quences. Studies are ongoing to determine if the observed inflammatory 
response will persist or it will disappear over time. 
Evaluation of an ongoing challenge study of rhesus suggests that the in- 
flammation response may disappear over time. Four rhesus (5. 1-8. 3 kg) were 
administered the AdRSV./Jgal vector to the lung (2-8xl0 9 pfu/kg via a bron- 
choscope to the large airways) (rhesus study 1C and 2C) . Animals were fol- 
lowed for 21 to 28 days and then re-challenged with the same vector, same 
dose, in the same location. Two control animals (vehicle followed by vehi- 
cle 21 or 28 days later) were evaluated in parallel. These 6 animals (4 
with repeat treatment, 2 control) have been followed for 180 to 187 days to 
date. No deaths or complications have occurred. Animals were followed with 
all of the parameters described in section 4.4; no abnormalities were 
observed in any parameter including the chest X-ray, arterial blood gases 
and lung compliance. Bronchoalveolar lavage of the 2 control animals showed 
no changes in total cells recovered or cell differential. In the 4 animals 
treated with vector and then challenged with the vector, the challenge was 
followed by an increase in cell number and proportion of lymphocytes. The 
data to date suggest the inflammatory response is resolved or resolving 
with return to baseline cell number, although the proportion of lymphocytes 
remain elevated. 
From these data, it can be concluded that re -challenge with the same recom- 
binant vector (should it be necessary) , will not be expected to have se- 
vere, acute clinical consequences. Studies are ongoing to determine the 
long term status of these animals. 
4.7 Is the Vector Shed Following Respiratory Administration of the Vector? 
A series of studies have been carried out which demonstrate that shedding 
occurs infrequently, and only at early times after administration of El - E3 - 
recombinant adenovirus administration. 
First, in cotton rats, intranasal administration of AvlCFl (10 10 pfu/kg) 
followed by wild type Ad5 (10 9 /pfu/kg) one week later (CRCW.003), evalua- 
tion of pharyngeal and rectal swabs for the presence of adenovirus revealed 
that : 
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Recombinant DNA Research, Volume 16 
