Demand for plasmid production growing says Cobra Biologics
Jerusalem, Israel-based BioCancell contracted Cobra to make its plasmid DNA drug candidate, BC-819, last week in preparation for Phase I clinical trials that are expected to start in 2015. Cobra will manufacture clinical batches at its microbial and virus production facility in Keele, UK.
Like viral vectors, plasmid DNA therapeutics are based on the concept of introducing selected genes into cells, rather than delivering the gene’s protein product, and fall under the concept of gene therapy.
BC-819 penetrates cancerous cells, under the control of the target genes H19 and P4-IGF2, activates the synthesis of Diphtheria Toxin A (DTA), killing the targeted cancer cell without damaging healthy cells.
The initial batches will be made at 50L scale, Cobra CEO Peter Coleman told Biopharma-Reporter.com, however, if the trials are successful there is scope for larger scale production at the firm's microbial fill/finish facility in Matfors, Sweden.
“The Keele site in particular has seen as resurgence in DNA activity in the last 12 months, with five new clients - including BioCancell - to add to our existing client base,” he told us. “To accommodate these new programs our team at Keele completed a major upgrade to GMP facilities and we are actively recruiting experienced scientists in both the UK and Sweden.”
Tony Hitchcock, Cobra’s Technical Director, added whilst the firm has been manufacturing this sort of technology for over 16 years, “plasmid therapeutics and DNA vaccines can be used to treat a broad range of therapeutic indications and so the market is likely to grow.”
Production Difficulties
Manufacturing any plasmid DNA vector is a challange according to Hitchcock, who cited such molecules' large size, relative physical and chemical fragility, and its chemical similarity to key contaminating molecules such as the cellular DNA, RNA and lipopolysaccharide (endotoxin) among the key hurdles.
“It is therefore essential to develop manufacturing processes to address these challenges and to exploit its properties with regards to separation are purification processes,” he told us.
“The issue of fragility is addressed by using low shear extraction approaches that allow for the extraction of the plasmid DNA molecule from the bacterial production cells in an intact manner, avoid shear and chemical damage, and then to use the properties of size, charge and hydrophobicity to separate this plasmid from key contaminants.”
Equipment
Hitchcock also spoke to us about the equipment Cobra used for such production: “Whilst the initial production in bacterial cultures are performed in classical stirred tank bioreactors, the chemical extraction of the plasmid from the cells is performed in custom mixing systems.”
“The subsequent purification operations are performed using standard chromatography and membrane based systems,” he added.
