Research Project
7405800
First generation non-replicative adenoviral vectors show promise as anti-cancer agents and as[unreadable] prophylactic vaccines. Current methods for manufacturing these vectors use either the 293 cell[unreadable] line or the PER.C6 cell line. These producer cells provide complementary E1a and E1b viral[unreadable] function in the cell for disabled adenoviral vectors. The 293 cell line has been very useful and[unreadable] widely used for making relatively small batches of vector for early stage clinical trials. However the[unreadable] frequency with which it generates replication competent adenovirus, which disqualifies from 10 to[unreadable] 50% of batches depending on the vector, means that, as the manufacturing processes are scaled[unreadable] up in later stage clinical trials, or for marketing, it becomes less and less acceptable. As scale[unreadable] increases, increasing numbers of batches exceed the FDA mandated allowable contamination[unreadable] level of 1RCA/3x10e10 viral particles, and such a manufacturing process cannot be claimed to be[unreadable] ?controlled? by FDA standards if the failure rate is greater than ~ 10%. PER.C6 cells use a[unreadable] specifically designed matched vector to eliminate sequence overlap between producer line and[unreadable] vector. The system is not compatible with most current clinical vectors and is not available to[unreadable] academic researchers or small companies. A modest 10 fold reduction in RCA frequency over[unreadable] that seen in 293 cells would provide a robust production system if the vector productivity were[unreadable] equivalent. We have constructed a cell line named c24 based on the human tumor line A549,[unreadable] which is as productive as 293 cells, is stable, is free of mycoplasma and carries 1-2 copies of an[unreadable] E1 expression plasmid with very limited overlap with conventional adenoviral vectors. We propose[unreadable] to rigorously test the RCA frequency in c24 compared to 293 cells, and to adapt it to serum free[unreadable] growth. If the RCA generation can be reduced by >10-fold, and in a serum free environment, then[unreadable] c24 can provide the basis for a reliable vector production system with a further improved safety[unreadable] profile that can be widely used to manufacture adenoviral vector products, including[unreadable] Advantagene?s own late stage pipeline.
