Pre-Banking And Avoiding Manufacturing Challenges For GMP Plasmids Containing Unstable Sequence Regions

By Luke Kroger, Director, GMP-Source Manufacturing and Pre-Production Planning, Aldevron

Ensuring consistent replication and proper retention of plasmid DNA sequence is vital to the economics and efficiency in generating starting materials used for production of adeno-associated virus (AAV) delivered gene therapy and messenger RNA (mRNA) vaccines and therapeutics. Plasmid DNA sequences often present challenges with certain notorious regions, such as inverted terminal repeats (ITRs) in constructs containing transgene sequences and long poly-A tail contents in mRNA template plasmids. Developers often struggle to maintain intact sequences when cloning into bacterial host cell strains, causing program delays and added cost to the pipeline.

Sponsors seeking a CDMO partner to manufacture plasmids are not always aware of the technical acumen required to overcome the stability complications these sequences inherently present.

Whether a client is focused on the investigation of potential mRNA vaccines or therapeutics or viral vector delivered therapies, their manufacturing partner must be able to provide and use cell strains that can reliably maintain the fidelity of the entire plasmid through the course of replication and scale-up growth.

One possible solution to this challenge includes identifying and transforming plasmid into multiple cell strains containing the necessary genetic characteristics required to improve the odds that the plasmids will properly maintain the structures enabling best performance in downstream applications. Effective clonal optimization relies upon a CDMO’s ability to create screening panels that incorporate the most critical elements of host design and plasmid in combination. Aldevron has developed a new approach to bacterial cell bank generation designed to benefit clients by ensuring optimal clone selection prior to and throughout the cell banking selection process.