Review Of mRNA Vaccines & Therapeutics Manufacturing Challenges: Plasmid DNA Manufacturing

By Dr. Catherine Jomary, Technology Lead ATMPs, IPS

The development and deployment of mRNA-based vaccines for SARS-CoV-2 have revolutionized mRNA therapeutics, and with ongoing advancements, mRNA technology holds immense promise for developing other vaccines and addressing unmet needs in non-viral gene and cell therapy applications. The mRNA manufacturing process involves the production of plasmid DNA (pDNA) as a critical starting material.

mRNA manufacturing challenges:

There are several challenges in manufacturing large-sized pDNAs, such as high viscosity, sensitivity to shearing, and similarity with impurities. These challenges can impact the mRNA manufacturing process. To overcome these challenges in mRNA manufacturing from plasmids, different strategies can be employed. For instance, centrifugation during E. coli harvest can induce DNA shearing, so microfiltration combined with tangential flow filtration (TFF) is recommended. Alkaline cell lysis can damage the supercoiled pDNA due to high viscosity, but controlling pH and mixing rate can mitigate this damage. Clarification steps can be improved using flow filtration with size exclusion and adsorption mechanisms, and an additional TFF step can be added for diafiltration. Chromatographic purification of pDNA can utilize either resins or membranes, with membranes being more suitable for large plasmids. Lastly, process development, single-use technology, and automation are crucial for reproducible and scalable manufacturing of pure pDNA.