Collaboration Aims to Address Large DNA Plasmid Scale-Up Issues

CDMO Biomay has teamed with BIA Separations to tackle bottlenecks in the cell lysis and purification stages of large DNA plasmid production.

Chromatographic column maker BIA Separations will work with Biomay to develop a high yield and purity manufacturing process for ‘large’ plasmid DNA used for therapeutic application.

Large plasmids are commonly used as starting materials for manufacturing of viral gene therapy vectors, said Hans Huber, COO of Biomay.

“For instance, manufacturing of the adeno-associated viral vector system (AAV) requires three types of gene: the coding gene of interest, the structural rep/cap genes of the AAV virus and the adenovirus helper genes,” Huber told BioProcess Insider.

“All these genes are delivered via plasmid vectors, and especially the 2-plasmid system result in big plasmids of more than 20 kbp. For manufacturing of the starting plasmids for AAV – or other viral systems as well – monoliths are therefore a predestined chromatography mode.”

‘Normal’ or ‘regular’ sized DNA Plasmids – with a size of 4-8 kilo base pairs (kbp) – usually contain one gene of interest (plus replication origin and selection marker), and can be manufactured routinely with resin/column based chromatography methods, Huber said.

Production Bottlenecks

But ‘large’ plasmids with a size beyond 15 kbp contain more than one gene of interest, and as many as four, are difficult to manufacture, with cell lysis and chromatographic purification representing potential scale-up bottlenecks.

“Classical resin-based chromatography lacks in poor plasmid binding capacity, resulting in big columns and large resin volumes, and the issue of low flow rates and high back pressure. Eventually longer processing times may result in poor plasmid homogeneity (supercoiled) due to degradation.

“All of these effects during scale-up are enforced particularly for large plasmids. In particular, large plasmids have significantly different binding and elution properties compared to moderate sized plasmids.”

Collaboration

The new process looks to overcome these issues. Biomay has developed the specific process parameters using BIA Separations’ platforms specifically with respect to manufacturing of large plasmids.

The process consists of E. coli high cell density fermentation, cell lysis and lysate conditioning optimized and targeted for convective interaction media (CIM), and a combination of monoliths / CIM operated at optimized conditions through load/binding, flow rates, elution profiles, and regeneration.

Huber told us this results in short processing time, high yield, and high quality in the case of large plasmids.

The developed process for large plasmids is being offered exclusively by Biomay to third party clients.