Sidebar: Using PER.C6 and XD to Increase Volumetric Productivity
According to Crucell, PER.C6® cells are becoming a popular platform for vaccine and recombinant protein manufacture due to the cells’ extremely high productivity, excellent safety record, scalability, and robust performance under high-shear conditions in serum-free media.
Percivia, a joint venture between Crucell and DSM Biologics, works extensively to develop platform technologies using PER.C6, particularly with XD™, an approach to cell culture that reportedly achieves volumetric productivity approaching 30 g/L.
What’s significant about this combination of cells and bioreactor technology is that it uses off-the-shelf media with minimal tweaking. “We really don’t do much in the way of media optimization,” says John H. Chon, Ph.D., director upstream process development at Percivia. “The media you use for your seed train works fine.”
Dr. Chon has instituted one major media improvement: using more concentrated media—about twice the standard concentrations—that is possible because XD is a highly efficient perfusion process and PER.C6 cells tolerate extremely high cell densities and concentrations of nutrients and recombinant mAb products, he says.
As a proponent of PER.C6, Dr. Chon is partial toward innate cell productivity compared with media development as the principal driver of cell culture productivity but recognizes that both are factors. “I’d say that nature and nurture are complimentary.”
Dr. Chon makes two observations on cell culture media markets:
- Every media manufacturer has a flagship medium that serves as a magic elixir for every cell line, but the top vendors provide a strategy for improving and customizing that product for individual customers.
- Cost-conscious end-users, particularly development-stage companies, can rarely afford the high costs of media development. Most, therefore, rely on vendors for such services. “The problem is that a media formulation is intellectual property, and under the terms of agreement it may belong to the vendor and not the drug developer.” Further on, when products reach late-stage testing, these sponsors (or companies that acquire them) may find themselves paying up to $50 per liter for media containing as little as $1 worth of ingredients.